65 files changed, 27067 insertions, 0 deletions

diff --git a/crates/ide_assists/src/assist_config.rs b/crates/ide_assists/src/assist_config.rs
new file mode 100644
index 000000000..9cabf037c
--- /dev/null
+++ b/crates/ide_assists/src/assist_config.rs
@@ -0,0 +1,16 @@
+//! Settings for tweaking assists.
+//!
+//! The fun thing here is `SnippetCap` -- this type can only be created in this
+//! module, and we use to statically check that we only produce snippet
+//! assists if we are allowed to.
+
+use ide_db::helpers::{insert_use::InsertUseConfig, SnippetCap};
+
+use crate::AssistKind;
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct AssistConfig {
+    pub snippet_cap: Option<SnippetCap>,
+    pub allowed: Option<Vec<AssistKind>>,
+    pub insert_use: InsertUseConfig,
+}
diff --git a/crates/ide_assists/src/assist_context.rs b/crates/ide_assists/src/assist_context.rs
new file mode 100644
index 000000000..bba6c08e0
--- /dev/null
+++ b/crates/ide_assists/src/assist_context.rs
@@ -0,0 +1,253 @@
+//! See `AssistContext`
+
+use std::mem;
+
+use hir::Semantics;
+use ide_db::{
+    base_db::{AnchoredPathBuf, FileId, FileRange},
+    helpers::SnippetCap,
+};
+use ide_db::{
+    label::Label,
+    source_change::{FileSystemEdit, SourceChange},
+    RootDatabase,
+};
+use syntax::{
+    algo::{self, find_node_at_offset, SyntaxRewriter},
+    AstNode, AstToken, SourceFile, SyntaxElement, SyntaxKind, SyntaxToken, TextRange, TextSize,
+    TokenAtOffset,
+};
+use text_edit::{TextEdit, TextEditBuilder};
+
+use crate::{assist_config::AssistConfig, Assist, AssistId, AssistKind, GroupLabel};
+
+/// `AssistContext` allows to apply an assist or check if it could be applied.
+///
+/// Assists use a somewhat over-engineered approach, given the current needs.
+/// The assists workflow consists of two phases. In the first phase, a user asks
+/// for the list of available assists. In the second phase, the user picks a
+/// particular assist and it gets applied.
+///
+/// There are two peculiarities here:
+///
+/// * first, we ideally avoid computing more things then necessary to answer "is
+///   assist applicable" in the first phase.
+/// * second, when we are applying assist, we don't have a guarantee that there
+///   weren't any changes between the point when user asked for assists and when
+///   they applied a particular assist. So, when applying assist, we need to do
+///   all the checks from scratch.
+///
+/// To avoid repeating the same code twice for both "check" and "apply"
+/// functions, we use an approach reminiscent of that of Django's function based
+/// views dealing with forms. Each assist receives a runtime parameter,
+/// `resolve`. It first check if an edit is applicable (potentially computing
+/// info required to compute the actual edit). If it is applicable, and
+/// `resolve` is `true`, it then computes the actual edit.
+///
+/// So, to implement the original assists workflow, we can first apply each edit
+/// with `resolve = false`, and then applying the selected edit again, with
+/// `resolve = true` this time.
+///
+/// Note, however, that we don't actually use such two-phase logic at the
+/// moment, because the LSP API is pretty awkward in this place, and it's much
+/// easier to just compute the edit eagerly :-)
+pub(crate) struct AssistContext<'a> {
+    pub(crate) config: &'a AssistConfig,
+    pub(crate) sema: Semantics<'a, RootDatabase>,
+    pub(crate) frange: FileRange,
+    source_file: SourceFile,
+}
+
+impl<'a> AssistContext<'a> {
+    pub(crate) fn new(
+        sema: Semantics<'a, RootDatabase>,
+        config: &'a AssistConfig,
+        frange: FileRange,
+    ) -> AssistContext<'a> {
+        let source_file = sema.parse(frange.file_id);
+        AssistContext { config, sema, frange, source_file }
+    }
+
+    pub(crate) fn db(&self) -> &RootDatabase {
+        self.sema.db
+    }
+
+    // NB, this ignores active selection.
+    pub(crate) fn offset(&self) -> TextSize {
+        self.frange.range.start()
+    }
+
+    pub(crate) fn token_at_offset(&self) -> TokenAtOffset<SyntaxToken> {
+        self.source_file.syntax().token_at_offset(self.offset())
+    }
+    pub(crate) fn find_token_syntax_at_offset(&self, kind: SyntaxKind) -> Option<SyntaxToken> {
+        self.token_at_offset().find(|it| it.kind() == kind)
+    }
+    pub(crate) fn find_token_at_offset<T: AstToken>(&self) -> Option<T> {
+        self.token_at_offset().find_map(T::cast)
+    }
+    pub(crate) fn find_node_at_offset<N: AstNode>(&self) -> Option<N> {
+        find_node_at_offset(self.source_file.syntax(), self.offset())
+    }
+    pub(crate) fn find_node_at_offset_with_descend<N: AstNode>(&self) -> Option<N> {
+        self.sema.find_node_at_offset_with_descend(self.source_file.syntax(), self.offset())
+    }
+    pub(crate) fn covering_element(&self) -> SyntaxElement {
+        self.source_file.syntax().covering_element(self.frange.range)
+    }
+    // FIXME: remove
+    pub(crate) fn covering_node_for_range(&self, range: TextRange) -> SyntaxElement {
+        self.source_file.syntax().covering_element(range)
+    }
+}
+
+pub(crate) struct Assists {
+    resolve: bool,
+    file: FileId,
+    buf: Vec<Assist>,
+    allowed: Option<Vec<AssistKind>>,
+}
+
+impl Assists {
+    pub(crate) fn new(ctx: &AssistContext, resolve: bool) -> Assists {
+        Assists {
+            resolve,
+            file: ctx.frange.file_id,
+            buf: Vec::new(),
+            allowed: ctx.config.allowed.clone(),
+        }
+    }
+
+    pub(crate) fn finish(mut self) -> Vec<Assist> {
+        self.buf.sort_by_key(|assist| assist.target.len());
+        self.buf
+    }
+
+    pub(crate) fn add(
+        &mut self,
+        id: AssistId,
+        label: impl Into<String>,
+        target: TextRange,
+        f: impl FnOnce(&mut AssistBuilder),
+    ) -> Option<()> {
+        if !self.is_allowed(&id) {
+            return None;
+        }
+        let label = Label::new(label.into());
+        let assist = Assist { id, label, group: None, target, source_change: None };
+        self.add_impl(assist, f)
+    }
+
+    pub(crate) fn add_group(
+        &mut self,
+        group: &GroupLabel,
+        id: AssistId,
+        label: impl Into<String>,
+        target: TextRange,
+        f: impl FnOnce(&mut AssistBuilder),
+    ) -> Option<()> {
+        if !self.is_allowed(&id) {
+            return None;
+        }
+        let label = Label::new(label.into());
+        let assist = Assist { id, label, group: Some(group.clone()), target, source_change: None };
+        self.add_impl(assist, f)
+    }
+
+    fn add_impl(&mut self, mut assist: Assist, f: impl FnOnce(&mut AssistBuilder)) -> Option<()> {
+        let source_change = if self.resolve {
+            let mut builder = AssistBuilder::new(self.file);
+            f(&mut builder);
+            Some(builder.finish())
+        } else {
+            None
+        };
+        assist.source_change = source_change;
+
+        self.buf.push(assist);
+        Some(())
+    }
+
+    fn is_allowed(&self, id: &AssistId) -> bool {
+        match &self.allowed {
+            Some(allowed) => allowed.iter().any(|kind| kind.contains(id.1)),
+            None => true,
+        }
+    }
+}
+
+pub(crate) struct AssistBuilder {
+    edit: TextEditBuilder,
+    file_id: FileId,
+    source_change: SourceChange,
+}
+
+impl AssistBuilder {
+    pub(crate) fn new(file_id: FileId) -> AssistBuilder {
+        AssistBuilder { edit: TextEdit::builder(), file_id, source_change: SourceChange::default() }
+    }
+
+    pub(crate) fn edit_file(&mut self, file_id: FileId) {
+        self.commit();
+        self.file_id = file_id;
+    }
+
+    fn commit(&mut self) {
+        let edit = mem::take(&mut self.edit).finish();
+        if !edit.is_empty() {
+            self.source_change.insert_source_edit(self.file_id, edit);
+        }
+    }
+
+    /// Remove specified `range` of text.
+    pub(crate) fn delete(&mut self, range: TextRange) {
+        self.edit.delete(range)
+    }
+    /// Append specified `text` at the given `offset`
+    pub(crate) fn insert(&mut self, offset: TextSize, text: impl Into<String>) {
+        self.edit.insert(offset, text.into())
+    }
+    /// Append specified `snippet` at the given `offset`
+    pub(crate) fn insert_snippet(
+        &mut self,
+        _cap: SnippetCap,
+        offset: TextSize,
+        snippet: impl Into<String>,
+    ) {
+        self.source_change.is_snippet = true;
+        self.insert(offset, snippet);
+    }
+    /// Replaces specified `range` of text with a given string.
+    pub(crate) fn replace(&mut self, range: TextRange, replace_with: impl Into<String>) {
+        self.edit.replace(range, replace_with.into())
+    }
+    /// Replaces specified `range` of text with a given `snippet`.
+    pub(crate) fn replace_snippet(
+        &mut self,
+        _cap: SnippetCap,
+        range: TextRange,
+        snippet: impl Into<String>,
+    ) {
+        self.source_change.is_snippet = true;
+        self.replace(range, snippet);
+    }
+    pub(crate) fn replace_ast<N: AstNode>(&mut self, old: N, new: N) {
+        algo::diff(old.syntax(), new.syntax()).into_text_edit(&mut self.edit)
+    }
+    pub(crate) fn rewrite(&mut self, rewriter: SyntaxRewriter) {
+        if let Some(node) = rewriter.rewrite_root() {
+            let new = rewriter.rewrite(&node);
+            algo::diff(&node, &new).into_text_edit(&mut self.edit);
+        }
+    }
+    pub(crate) fn create_file(&mut self, dst: AnchoredPathBuf, content: impl Into<String>) {
+        let file_system_edit =
+            FileSystemEdit::CreateFile { dst: dst, initial_contents: content.into() };
+        self.source_change.push_file_system_edit(file_system_edit);
+    }
+
+    fn finish(mut self) -> SourceChange {
+        self.commit();
+        mem::take(&mut self.source_change)
+    }
+}
diff --git a/crates/ide_assists/src/ast_transform.rs b/crates/ide_assists/src/ast_transform.rs
new file mode 100644
index 000000000..4a3ed7783
--- /dev/null
+++ b/crates/ide_assists/src/ast_transform.rs
@@ -0,0 +1,213 @@
+//! `AstTransformer`s are functions that replace nodes in an AST and can be easily combined.
+use hir::{HirDisplay, PathResolution, SemanticsScope};
+use ide_db::helpers::mod_path_to_ast;
+use rustc_hash::FxHashMap;
+use syntax::{
+    algo::SyntaxRewriter,
+    ast::{self, AstNode},
+    SyntaxNode,
+};
+
+pub fn apply<'a, N: AstNode>(transformer: &dyn AstTransform<'a>, node: N) -> N {
+    SyntaxRewriter::from_fn(|element| match element {
+        syntax::SyntaxElement::Node(n) => {
+            let replacement = transformer.get_substitution(&n, transformer)?;
+            Some(replacement.into())
+        }
+        _ => None,
+    })
+    .rewrite_ast(&node)
+}
+
+/// `AstTransform` helps with applying bulk transformations to syntax nodes.
+///
+/// This is mostly useful for IDE code generation. If you paste some existing
+/// code into a new context (for example, to add method overrides to an `impl`
+/// block), you generally want to appropriately qualify the names, and sometimes
+/// you might want to substitute generic parameters as well:
+///
+/// ```
+/// mod x {
+///   pub struct A;
+///   pub trait T<U> { fn foo(&self, _: U) -> A; }
+/// }
+///
+/// mod y {
+///   use x::T;
+///
+///   impl T<()> for () {
+///      // If we invoke **Add Missing Members** here, we want to copy-paste `foo`.
+///      // But we want a slightly-modified version of it:
+///      fn foo(&self, _: ()) -> x::A {}
+///   }
+/// }
+/// ```
+///
+/// So, a single `AstTransform` describes such function from `SyntaxNode` to
+/// `SyntaxNode`. Note that the API here is a bit too high-order and high-brow.
+/// We'd want to somehow express this concept simpler, but so far nobody got to
+/// simplifying this!
+pub trait AstTransform<'a> {
+    fn get_substitution(
+        &self,
+        node: &SyntaxNode,
+        recur: &dyn AstTransform<'a>,
+    ) -> Option<SyntaxNode>;
+
+    fn or<T: AstTransform<'a> + 'a>(self, other: T) -> Box<dyn AstTransform<'a> + 'a>
+    where
+        Self: Sized + 'a,
+    {
+        Box::new(Or(Box::new(self), Box::new(other)))
+    }
+}
+
+struct Or<'a>(Box<dyn AstTransform<'a> + 'a>, Box<dyn AstTransform<'a> + 'a>);
+
+impl<'a> AstTransform<'a> for Or<'a> {
+    fn get_substitution(
+        &self,
+        node: &SyntaxNode,
+        recur: &dyn AstTransform<'a>,
+    ) -> Option<SyntaxNode> {
+        self.0.get_substitution(node, recur).or_else(|| self.1.get_substitution(node, recur))
+    }
+}
+
+pub struct SubstituteTypeParams<'a> {
+    source_scope: &'a SemanticsScope<'a>,
+    substs: FxHashMap<hir::TypeParam, ast::Type>,
+}
+
+impl<'a> SubstituteTypeParams<'a> {
+    pub fn for_trait_impl(
+        source_scope: &'a SemanticsScope<'a>,
+        // FIXME: there's implicit invariant that `trait_` and  `source_scope` match...
+        trait_: hir::Trait,
+        impl_def: ast::Impl,
+    ) -> SubstituteTypeParams<'a> {
+        let substs = get_syntactic_substs(impl_def).unwrap_or_default();
+        let generic_def: hir::GenericDef = trait_.into();
+        let substs_by_param: FxHashMap<_, _> = generic_def
+            .type_params(source_scope.db)
+            .into_iter()
+            // this is a trait impl, so we need to skip the first type parameter -- this is a bit hacky
+            .skip(1)
+            // The actual list of trait type parameters may be longer than the one
+            // used in the `impl` block due to trailing default type parameters.
+            // For that case we extend the `substs` with an empty iterator so we
+            // can still hit those trailing values and check if they actually have
+            // a default type. If they do, go for that type from `hir` to `ast` so
+            // the resulting change can be applied correctly.
+            .zip(substs.into_iter().map(Some).chain(std::iter::repeat(None)))
+            .filter_map(|(k, v)| match v {
+                Some(v) => Some((k, v)),
+                None => {
+                    let default = k.default(source_scope.db)?;
+                    Some((
+                        k,
+                        ast::make::ty(
+                            &default
+                                .display_source_code(source_scope.db, source_scope.module()?.into())
+                                .ok()?,
+                        ),
+                    ))
+                }
+            })
+            .collect();
+        return SubstituteTypeParams { source_scope, substs: substs_by_param };
+
+        // FIXME: It would probably be nicer if we could get this via HIR (i.e. get the
+        // trait ref, and then go from the types in the substs back to the syntax).
+        fn get_syntactic_substs(impl_def: ast::Impl) -> Option<Vec<ast::Type>> {
+            let target_trait = impl_def.trait_()?;
+            let path_type = match target_trait {
+                ast::Type::PathType(path) => path,
+                _ => return None,
+            };
+            let generic_arg_list = path_type.path()?.segment()?.generic_arg_list()?;
+
+            let mut result = Vec::new();
+            for generic_arg in generic_arg_list.generic_args() {
+                match generic_arg {
+                    ast::GenericArg::TypeArg(type_arg) => result.push(type_arg.ty()?),
+                    ast::GenericArg::AssocTypeArg(_)
+                    | ast::GenericArg::LifetimeArg(_)
+                    | ast::GenericArg::ConstArg(_) => (),
+                }
+            }
+
+            Some(result)
+        }
+    }
+}
+
+impl<'a> AstTransform<'a> for SubstituteTypeParams<'a> {
+    fn get_substitution(
+        &self,
+        node: &SyntaxNode,
+        _recur: &dyn AstTransform<'a>,
+    ) -> Option<SyntaxNode> {
+        let type_ref = ast::Type::cast(node.clone())?;
+        let path = match &type_ref {
+            ast::Type::PathType(path_type) => path_type.path()?,
+            _ => return None,
+        };
+        let resolution = self.source_scope.speculative_resolve(&path)?;
+        match resolution {
+            hir::PathResolution::TypeParam(tp) => Some(self.substs.get(&tp)?.syntax().clone()),
+            _ => None,
+        }
+    }
+}
+
+pub struct QualifyPaths<'a> {
+    target_scope: &'a SemanticsScope<'a>,
+    source_scope: &'a SemanticsScope<'a>,
+}
+
+impl<'a> QualifyPaths<'a> {
+    pub fn new(target_scope: &'a SemanticsScope<'a>, source_scope: &'a SemanticsScope<'a>) -> Self {
+        Self { target_scope, source_scope }
+    }
+}
+
+impl<'a> AstTransform<'a> for QualifyPaths<'a> {
+    fn get_substitution(
+        &self,
+        node: &SyntaxNode,
+        recur: &dyn AstTransform<'a>,
+    ) -> Option<SyntaxNode> {
+        // FIXME handle value ns?
+        let from = self.target_scope.module()?;
+        let p = ast::Path::cast(node.clone())?;
+        if p.segment().and_then(|s| s.param_list()).is_some() {
+            // don't try to qualify `Fn(Foo) -> Bar` paths, they are in prelude anyway
+            return None;
+        }
+        let resolution = self.source_scope.speculative_resolve(&p)?;
+        match resolution {
+            PathResolution::Def(def) => {
+                let found_path = from.find_use_path(self.source_scope.db.upcast(), def)?;
+                let mut path = mod_path_to_ast(&found_path);
+
+                let type_args = p
+                    .segment()
+                    .and_then(|s| s.generic_arg_list())
+                    .map(|arg_list| apply(recur, arg_list));
+                if let Some(type_args) = type_args {
+                    let last_segment = path.segment().unwrap();
+                    path = path.with_segment(last_segment.with_generic_args(type_args))
+                }
+
+                Some(path.syntax().clone())
+            }
+            PathResolution::Local(_)
+            | PathResolution::TypeParam(_)
+            | PathResolution::SelfType(_)
+            | PathResolution::ConstParam(_) => None,
+            PathResolution::Macro(_) => None,
+            PathResolution::AssocItem(_) => None,
+        }
+    }
+}
diff --git a/crates/ide_assists/src/handlers/add_explicit_type.rs b/crates/ide_assists/src/handlers/add_explicit_type.rs
new file mode 100644
index 000000000..cb1548cef
--- /dev/null
+++ b/crates/ide_assists/src/handlers/add_explicit_type.rs
@@ -0,0 +1,207 @@
+use hir::HirDisplay;
+use syntax::{
+    ast::{self, AstNode, LetStmt, NameOwner},
+    TextRange,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: add_explicit_type
+//
+// Specify type for a let binding.
+//
+// ```
+// fn main() {
+//     let x$0 = 92;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     let x: i32 = 92;
+// }
+// ```
+pub(crate) fn add_explicit_type(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let let_stmt = ctx.find_node_at_offset::<LetStmt>()?;
+    let module = ctx.sema.scope(let_stmt.syntax()).module()?;
+    let expr = let_stmt.initializer()?;
+    // Must be a binding
+    let pat = match let_stmt.pat()? {
+        ast::Pat::IdentPat(bind_pat) => bind_pat,
+        _ => return None,
+    };
+    let pat_range = pat.syntax().text_range();
+    // The binding must have a name
+    let name = pat.name()?;
+    let name_range = name.syntax().text_range();
+    let stmt_range = let_stmt.syntax().text_range();
+    let eq_range = let_stmt.eq_token()?.text_range();
+    // Assist should only be applicable if cursor is between 'let' and '='
+    let let_range = TextRange::new(stmt_range.start(), eq_range.start());
+    let cursor_in_range = let_range.contains_range(ctx.frange.range);
+    if !cursor_in_range {
+        return None;
+    }
+    // Assist not applicable if the type has already been specified
+    // and it has no placeholders
+    let ascribed_ty = let_stmt.ty();
+    if let Some(ty) = &ascribed_ty {
+        if ty.syntax().descendants().find_map(ast::InferType::cast).is_none() {
+            return None;
+        }
+    }
+    // Infer type
+    let ty = ctx.sema.type_of_expr(&expr)?;
+
+    if ty.contains_unknown() || ty.is_closure() {
+        return None;
+    }
+
+    let inferred_type = ty.display_source_code(ctx.db(), module.into()).ok()?;
+    acc.add(
+        AssistId("add_explicit_type", AssistKind::RefactorRewrite),
+        format!("Insert explicit type `{}`", inferred_type),
+        pat_range,
+        |builder| match ascribed_ty {
+            Some(ascribed_ty) => {
+                builder.replace(ascribed_ty.syntax().text_range(), inferred_type);
+            }
+            None => {
+                builder.insert(name_range.end(), format!(": {}", inferred_type));
+            }
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    #[test]
+    fn add_explicit_type_target() {
+        check_assist_target(add_explicit_type, "fn f() { let a$0 = 1; }", "a");
+    }
+
+    #[test]
+    fn add_explicit_type_works_for_simple_expr() {
+        check_assist(add_explicit_type, "fn f() { let a$0 = 1; }", "fn f() { let a: i32 = 1; }");
+    }
+
+    #[test]
+    fn add_explicit_type_works_for_underscore() {
+        check_assist(add_explicit_type, "fn f() { let a$0: _ = 1; }", "fn f() { let a: i32 = 1; }");
+    }
+
+    #[test]
+    fn add_explicit_type_works_for_nested_underscore() {
+        check_assist(
+            add_explicit_type,
+            r#"
+            enum Option<T> {
+                Some(T),
+                None
+            }
+
+            fn f() {
+                let a$0: Option<_> = Option::Some(1);
+            }"#,
+            r#"
+            enum Option<T> {
+                Some(T),
+                None
+            }
+
+            fn f() {
+                let a: Option<i32> = Option::Some(1);
+            }"#,
+        );
+    }
+
+    #[test]
+    fn add_explicit_type_works_for_macro_call() {
+        check_assist(
+            add_explicit_type,
+            r"macro_rules! v { () => {0u64} } fn f() { let a$0 = v!(); }",
+            r"macro_rules! v { () => {0u64} } fn f() { let a: u64 = v!(); }",
+        );
+    }
+
+    #[test]
+    fn add_explicit_type_works_for_macro_call_recursive() {
+        check_assist(
+            add_explicit_type,
+            r#"macro_rules! u { () => {0u64} } macro_rules! v { () => {u!()} } fn f() { let a$0 = v!(); }"#,
+            r#"macro_rules! u { () => {0u64} } macro_rules! v { () => {u!()} } fn f() { let a: u64 = v!(); }"#,
+        );
+    }
+
+    #[test]
+    fn add_explicit_type_not_applicable_if_ty_not_inferred() {
+        check_assist_not_applicable(add_explicit_type, "fn f() { let a$0 = None; }");
+    }
+
+    #[test]
+    fn add_explicit_type_not_applicable_if_ty_already_specified() {
+        check_assist_not_applicable(add_explicit_type, "fn f() { let a$0: i32 = 1; }");
+    }
+
+    #[test]
+    fn add_explicit_type_not_applicable_if_specified_ty_is_tuple() {
+        check_assist_not_applicable(add_explicit_type, "fn f() { let a$0: (i32, i32) = (3, 4); }");
+    }
+
+    #[test]
+    fn add_explicit_type_not_applicable_if_cursor_after_equals() {
+        check_assist_not_applicable(
+            add_explicit_type,
+            "fn f() {let a =$0 match 1 {2 => 3, 3 => 5};}",
+        )
+    }
+
+    #[test]
+    fn add_explicit_type_not_applicable_if_cursor_before_let() {
+        check_assist_not_applicable(
+            add_explicit_type,
+            "fn f() $0{let a = match 1 {2 => 3, 3 => 5};}",
+        )
+    }
+
+    #[test]
+    fn closure_parameters_are_not_added() {
+        check_assist_not_applicable(
+            add_explicit_type,
+            r#"
+fn main() {
+    let multiply_by_two$0 = |i| i * 3;
+    let six = multiply_by_two(2);
+}"#,
+        )
+    }
+
+    #[test]
+    fn default_generics_should_not_be_added() {
+        check_assist(
+            add_explicit_type,
+            r#"
+struct Test<K, T = u8> {
+    k: K,
+    t: T,
+}
+
+fn main() {
+    let test$0 = Test { t: 23u8, k: 33 };
+}"#,
+            r#"
+struct Test<K, T = u8> {
+    k: K,
+    t: T,
+}
+
+fn main() {
+    let test: Test<i32> = Test { t: 23u8, k: 33 };
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/add_lifetime_to_type.rs b/crates/ide_assists/src/handlers/add_lifetime_to_type.rs
new file mode 100644
index 000000000..2edf7b204
--- /dev/null
+++ b/crates/ide_assists/src/handlers/add_lifetime_to_type.rs
@@ -0,0 +1,228 @@
+use ast::FieldList;
+use syntax::ast::{self, AstNode, GenericParamsOwner, NameOwner, RefType, Type};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: add_lifetime_to_type
+//
+// Adds a new lifetime to a struct, enum or union.
+//
+// ```
+// struct Point {
+//     x: &$0u32,
+//     y: u32,
+// }
+// ```
+// ->
+// ```
+// struct Point<'a> {
+//     x: &'a u32,
+//     y: u32,
+// }
+// ```
+pub(crate) fn add_lifetime_to_type(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let ref_type_focused = ctx.find_node_at_offset::<ast::RefType>()?;
+    if ref_type_focused.lifetime().is_some() {
+        return None;
+    }
+
+    let node = ctx.find_node_at_offset::<ast::Adt>()?;
+    let has_lifetime = node
+        .generic_param_list()
+        .map(|gen_list| gen_list.lifetime_params().count() > 0)
+        .unwrap_or_default();
+
+    if has_lifetime {
+        return None;
+    }
+
+    let ref_types = fetch_borrowed_types(&node)?;
+    let target = node.syntax().text_range();
+
+    acc.add(
+        AssistId("add_lifetime_to_type", AssistKind::Generate),
+        "Add lifetime`",
+        target,
+        |builder| {
+            match node.generic_param_list() {
+                Some(gen_param) => {
+                    if let Some(left_angle) = gen_param.l_angle_token() {
+                        builder.insert(left_angle.text_range().end(), "'a, ");
+                    }
+                }
+                None => {
+                    if let Some(name) = node.name() {
+                        builder.insert(name.syntax().text_range().end(), "<'a>");
+                    }
+                }
+            }
+
+            for ref_type in ref_types {
+                if let Some(amp_token) = ref_type.amp_token() {
+                    builder.insert(amp_token.text_range().end(), "'a ");
+                }
+            }
+        },
+    )
+}
+
+fn fetch_borrowed_types(node: &ast::Adt) -> Option<Vec<RefType>> {
+    let ref_types: Vec<RefType> = match node {
+        ast::Adt::Enum(enum_) => {
+            let variant_list = enum_.variant_list()?;
+            variant_list
+                .variants()
+                .filter_map(|variant| {
+                    let field_list = variant.field_list()?;
+
+                    find_ref_types_from_field_list(&field_list)
+                })
+                .flatten()
+                .collect()
+        }
+        ast::Adt::Struct(strukt) => {
+            let field_list = strukt.field_list()?;
+            find_ref_types_from_field_list(&field_list)?
+        }
+        ast::Adt::Union(un) => {
+            let record_field_list = un.record_field_list()?;
+            record_field_list
+                .fields()
+                .filter_map(|r_field| {
+                    if let Type::RefType(ref_type) = r_field.ty()? {
+                        if ref_type.lifetime().is_none() {
+                            return Some(ref_type);
+                        }
+                    }
+
+                    None
+                })
+                .collect()
+        }
+    };
+
+    if ref_types.is_empty() {
+        None
+    } else {
+        Some(ref_types)
+    }
+}
+
+fn find_ref_types_from_field_list(field_list: &FieldList) -> Option<Vec<RefType>> {
+    let ref_types: Vec<RefType> = match field_list {
+        ast::FieldList::RecordFieldList(record_list) => record_list
+            .fields()
+            .filter_map(|f| {
+                if let Type::RefType(ref_type) = f.ty()? {
+                    if ref_type.lifetime().is_none() {
+                        return Some(ref_type);
+                    }
+                }
+
+                None
+            })
+            .collect(),
+        ast::FieldList::TupleFieldList(tuple_field_list) => tuple_field_list
+            .fields()
+            .filter_map(|f| {
+                if let Type::RefType(ref_type) = f.ty()? {
+                    if ref_type.lifetime().is_none() {
+                        return Some(ref_type);
+                    }
+                }
+
+                None
+            })
+            .collect(),
+    };
+
+    if ref_types.is_empty() {
+        None
+    } else {
+        Some(ref_types)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn add_lifetime_to_struct() {
+        check_assist(
+            add_lifetime_to_type,
+            "struct Foo { a: &$0i32 }",
+            "struct Foo<'a> { a: &'a i32 }",
+        );
+
+        check_assist(
+            add_lifetime_to_type,
+            "struct Foo { a: &$0i32, b: &usize }",
+            "struct Foo<'a> { a: &'a i32, b: &'a usize }",
+        );
+
+        check_assist(
+            add_lifetime_to_type,
+            "struct Foo { a: &$0i32, b: usize }",
+            "struct Foo<'a> { a: &'a i32, b: usize }",
+        );
+
+        check_assist(
+            add_lifetime_to_type,
+            "struct Foo<T> { a: &$0T, b: usize }",
+            "struct Foo<'a, T> { a: &'a T, b: usize }",
+        );
+
+        check_assist_not_applicable(add_lifetime_to_type, "struct Foo<'a> { a: &$0'a i32 }");
+        check_assist_not_applicable(add_lifetime_to_type, "struct Foo { a: &'a$0 i32 }");
+    }
+
+    #[test]
+    fn add_lifetime_to_enum() {
+        check_assist(
+            add_lifetime_to_type,
+            "enum Foo { Bar { a: i32 }, Other, Tuple(u32, &$0u32)}",
+            "enum Foo<'a> { Bar { a: i32 }, Other, Tuple(u32, &'a u32)}",
+        );
+
+        check_assist(
+            add_lifetime_to_type,
+            "enum Foo { Bar { a: &$0i32 }}",
+            "enum Foo<'a> { Bar { a: &'a i32 }}",
+        );
+
+        check_assist(
+            add_lifetime_to_type,
+            "enum Foo<T> { Bar { a: &$0i32, b: &T }}",
+            "enum Foo<'a, T> { Bar { a: &'a i32, b: &'a T }}",
+        );
+
+        check_assist_not_applicable(add_lifetime_to_type, "enum Foo<'a> { Bar { a: &$0'a i32 }}");
+        check_assist_not_applicable(add_lifetime_to_type, "enum Foo { Bar, $0Misc }");
+    }
+
+    #[test]
+    fn add_lifetime_to_union() {
+        check_assist(
+            add_lifetime_to_type,
+            "union Foo { a: &$0i32 }",
+            "union Foo<'a> { a: &'a i32 }",
+        );
+
+        check_assist(
+            add_lifetime_to_type,
+            "union Foo { a: &$0i32, b: &usize }",
+            "union Foo<'a> { a: &'a i32, b: &'a usize }",
+        );
+
+        check_assist(
+            add_lifetime_to_type,
+            "union Foo<T> { a: &$0T, b: usize }",
+            "union Foo<'a, T> { a: &'a T, b: usize }",
+        );
+
+        check_assist_not_applicable(add_lifetime_to_type, "struct Foo<'a> { a: &'a $0i32 }");
+    }
+}
diff --git a/crates/ide_assists/src/handlers/add_missing_impl_members.rs b/crates/ide_assists/src/handlers/add_missing_impl_members.rs
new file mode 100644
index 000000000..63cea754d
--- /dev/null
+++ b/crates/ide_assists/src/handlers/add_missing_impl_members.rs
@@ -0,0 +1,814 @@
+use ide_db::traits::resolve_target_trait;
+use syntax::ast::{self, AstNode};
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    utils::add_trait_assoc_items_to_impl,
+    utils::DefaultMethods,
+    utils::{filter_assoc_items, render_snippet, Cursor},
+    AssistId, AssistKind,
+};
+
+// Assist: add_impl_missing_members
+//
+// Adds scaffold for required impl members.
+//
+// ```
+// trait Trait<T> {
+//     type X;
+//     fn foo(&self) -> T;
+//     fn bar(&self) {}
+// }
+//
+// impl Trait<u32> for () {$0
+//
+// }
+// ```
+// ->
+// ```
+// trait Trait<T> {
+//     type X;
+//     fn foo(&self) -> T;
+//     fn bar(&self) {}
+// }
+//
+// impl Trait<u32> for () {
+//     $0type X;
+//
+//     fn foo(&self) -> u32 {
+//         todo!()
+//     }
+// }
+// ```
+pub(crate) fn add_missing_impl_members(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    add_missing_impl_members_inner(
+        acc,
+        ctx,
+        DefaultMethods::No,
+        "add_impl_missing_members",
+        "Implement missing members",
+    )
+}
+
+// Assist: add_impl_default_members
+//
+// Adds scaffold for overriding default impl members.
+//
+// ```
+// trait Trait {
+//     type X;
+//     fn foo(&self);
+//     fn bar(&self) {}
+// }
+//
+// impl Trait for () {
+//     type X = ();
+//     fn foo(&self) {}$0
+//
+// }
+// ```
+// ->
+// ```
+// trait Trait {
+//     type X;
+//     fn foo(&self);
+//     fn bar(&self) {}
+// }
+//
+// impl Trait for () {
+//     type X = ();
+//     fn foo(&self) {}
+//
+//     $0fn bar(&self) {}
+// }
+// ```
+pub(crate) fn add_missing_default_members(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    add_missing_impl_members_inner(
+        acc,
+        ctx,
+        DefaultMethods::Only,
+        "add_impl_default_members",
+        "Implement default members",
+    )
+}
+
+fn add_missing_impl_members_inner(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+    mode: DefaultMethods,
+    assist_id: &'static str,
+    label: &'static str,
+) -> Option<()> {
+    let _p = profile::span("add_missing_impl_members_inner");
+    let impl_def = ctx.find_node_at_offset::<ast::Impl>()?;
+    let trait_ = resolve_target_trait(&ctx.sema, &impl_def)?;
+
+    let missing_items = filter_assoc_items(
+        ctx.db(),
+        &ide_db::traits::get_missing_assoc_items(&ctx.sema, &impl_def),
+        mode,
+    );
+
+    if missing_items.is_empty() {
+        return None;
+    }
+
+    let target = impl_def.syntax().text_range();
+    acc.add(AssistId(assist_id, AssistKind::QuickFix), label, target, |builder| {
+        let target_scope = ctx.sema.scope(impl_def.syntax());
+        let (new_impl_def, first_new_item) =
+            add_trait_assoc_items_to_impl(&ctx.sema, missing_items, trait_, impl_def, target_scope);
+        match ctx.config.snippet_cap {
+            None => builder.replace(target, new_impl_def.to_string()),
+            Some(cap) => {
+                let mut cursor = Cursor::Before(first_new_item.syntax());
+                let placeholder;
+                if let ast::AssocItem::Fn(func) = &first_new_item {
+                    if let Some(m) = func.syntax().descendants().find_map(ast::MacroCall::cast) {
+                        if m.syntax().text() == "todo!()" {
+                            placeholder = m;
+                            cursor = Cursor::Replace(placeholder.syntax());
+                        }
+                    }
+                }
+                builder.replace_snippet(
+                    cap,
+                    target,
+                    render_snippet(cap, new_impl_def.syntax(), cursor),
+                )
+            }
+        };
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn test_add_missing_impl_members() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo {
+    type Output;
+
+    const CONST: usize = 42;
+
+    fn foo(&self);
+    fn bar(&self);
+    fn baz(&self);
+}
+
+struct S;
+
+impl Foo for S {
+    fn bar(&self) {}
+$0
+}"#,
+            r#"
+trait Foo {
+    type Output;
+
+    const CONST: usize = 42;
+
+    fn foo(&self);
+    fn bar(&self);
+    fn baz(&self);
+}
+
+struct S;
+
+impl Foo for S {
+    fn bar(&self) {}
+
+    $0type Output;
+
+    const CONST: usize = 42;
+
+    fn foo(&self) {
+        todo!()
+    }
+
+    fn baz(&self) {
+        todo!()
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_copied_overriden_members() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo {
+    fn foo(&self);
+    fn bar(&self) -> bool { true }
+    fn baz(&self) -> u32 { 42 }
+}
+
+struct S;
+
+impl Foo for S {
+    fn bar(&self) {}
+$0
+}"#,
+            r#"
+trait Foo {
+    fn foo(&self);
+    fn bar(&self) -> bool { true }
+    fn baz(&self) -> u32 { 42 }
+}
+
+struct S;
+
+impl Foo for S {
+    fn bar(&self) {}
+
+    fn foo(&self) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_empty_impl_def() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo { fn foo(&self); }
+struct S;
+impl Foo for S { $0 }"#,
+            r#"
+trait Foo { fn foo(&self); }
+struct S;
+impl Foo for S {
+    fn foo(&self) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_impl_def_without_braces() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo { fn foo(&self); }
+struct S;
+impl Foo for S$0"#,
+            r#"
+trait Foo { fn foo(&self); }
+struct S;
+impl Foo for S {
+    fn foo(&self) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn fill_in_type_params_1() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo<T> { fn foo(&self, t: T) -> &T; }
+struct S;
+impl Foo<u32> for S { $0 }"#,
+            r#"
+trait Foo<T> { fn foo(&self, t: T) -> &T; }
+struct S;
+impl Foo<u32> for S {
+    fn foo(&self, t: u32) -> &u32 {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn fill_in_type_params_2() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo<T> { fn foo(&self, t: T) -> &T; }
+struct S;
+impl<U> Foo<U> for S { $0 }"#,
+            r#"
+trait Foo<T> { fn foo(&self, t: T) -> &T; }
+struct S;
+impl<U> Foo<U> for S {
+    fn foo(&self, t: U) -> &U {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_cursor_after_empty_impl_def() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo { fn foo(&self); }
+struct S;
+impl Foo for S {}$0"#,
+            r#"
+trait Foo { fn foo(&self); }
+struct S;
+impl Foo for S {
+    fn foo(&self) {
+        ${0:todo!()}
+    }
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_qualify_path_1() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+mod foo {
+    pub struct Bar;
+    trait Foo { fn foo(&self, bar: Bar); }
+}
+struct S;
+impl foo::Foo for S { $0 }"#,
+            r#"
+mod foo {
+    pub struct Bar;
+    trait Foo { fn foo(&self, bar: Bar); }
+}
+struct S;
+impl foo::Foo for S {
+    fn foo(&self, bar: foo::Bar) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_qualify_path_2() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub trait Foo { fn foo(&self, bar: Bar); }
+    }
+}
+
+use foo::bar;
+
+struct S;
+impl bar::Foo for S { $0 }"#,
+            r#"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub trait Foo { fn foo(&self, bar: Bar); }
+    }
+}
+
+use foo::bar;
+
+struct S;
+impl bar::Foo for S {
+    fn foo(&self, bar: bar::Bar) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_qualify_path_generic() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+mod foo {
+    pub struct Bar<T>;
+    trait Foo { fn foo(&self, bar: Bar<u32>); }
+}
+struct S;
+impl foo::Foo for S { $0 }"#,
+            r#"
+mod foo {
+    pub struct Bar<T>;
+    trait Foo { fn foo(&self, bar: Bar<u32>); }
+}
+struct S;
+impl foo::Foo for S {
+    fn foo(&self, bar: foo::Bar<u32>) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_qualify_path_and_substitute_param() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+mod foo {
+    pub struct Bar<T>;
+    trait Foo<T> { fn foo(&self, bar: Bar<T>); }
+}
+struct S;
+impl foo::Foo<u32> for S { $0 }"#,
+            r#"
+mod foo {
+    pub struct Bar<T>;
+    trait Foo<T> { fn foo(&self, bar: Bar<T>); }
+}
+struct S;
+impl foo::Foo<u32> for S {
+    fn foo(&self, bar: foo::Bar<u32>) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_substitute_param_no_qualify() {
+        // when substituting params, the substituted param should not be qualified!
+        check_assist(
+            add_missing_impl_members,
+            r#"
+mod foo {
+    trait Foo<T> { fn foo(&self, bar: T); }
+    pub struct Param;
+}
+struct Param;
+struct S;
+impl foo::Foo<Param> for S { $0 }"#,
+            r#"
+mod foo {
+    trait Foo<T> { fn foo(&self, bar: T); }
+    pub struct Param;
+}
+struct Param;
+struct S;
+impl foo::Foo<Param> for S {
+    fn foo(&self, bar: Param) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_qualify_path_associated_item() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+mod foo {
+    pub struct Bar<T>;
+    impl Bar<T> { type Assoc = u32; }
+    trait Foo { fn foo(&self, bar: Bar<u32>::Assoc); }
+}
+struct S;
+impl foo::Foo for S { $0 }"#,
+            r#"
+mod foo {
+    pub struct Bar<T>;
+    impl Bar<T> { type Assoc = u32; }
+    trait Foo { fn foo(&self, bar: Bar<u32>::Assoc); }
+}
+struct S;
+impl foo::Foo for S {
+    fn foo(&self, bar: foo::Bar<u32>::Assoc) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_qualify_path_nested() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+mod foo {
+    pub struct Bar<T>;
+    pub struct Baz;
+    trait Foo { fn foo(&self, bar: Bar<Baz>); }
+}
+struct S;
+impl foo::Foo for S { $0 }"#,
+            r#"
+mod foo {
+    pub struct Bar<T>;
+    pub struct Baz;
+    trait Foo { fn foo(&self, bar: Bar<Baz>); }
+}
+struct S;
+impl foo::Foo for S {
+    fn foo(&self, bar: foo::Bar<foo::Baz>) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_qualify_path_fn_trait_notation() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+mod foo {
+    pub trait Fn<Args> { type Output; }
+    trait Foo { fn foo(&self, bar: dyn Fn(u32) -> i32); }
+}
+struct S;
+impl foo::Foo for S { $0 }"#,
+            r#"
+mod foo {
+    pub trait Fn<Args> { type Output; }
+    trait Foo { fn foo(&self, bar: dyn Fn(u32) -> i32); }
+}
+struct S;
+impl foo::Foo for S {
+    fn foo(&self, bar: dyn Fn(u32) -> i32) {
+        ${0:todo!()}
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_empty_trait() {
+        check_assist_not_applicable(
+            add_missing_impl_members,
+            r#"
+trait Foo;
+struct S;
+impl Foo for S { $0 }"#,
+        )
+    }
+
+    #[test]
+    fn test_ignore_unnamed_trait_members_and_default_methods() {
+        check_assist_not_applicable(
+            add_missing_impl_members,
+            r#"
+trait Foo {
+    fn (arg: u32);
+    fn valid(some: u32) -> bool { false }
+}
+struct S;
+impl Foo for S { $0 }"#,
+        )
+    }
+
+    #[test]
+    fn test_with_docstring_and_attrs() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+#[doc(alias = "test alias")]
+trait Foo {
+    /// doc string
+    type Output;
+
+    #[must_use]
+    fn foo(&self);
+}
+struct S;
+impl Foo for S {}$0"#,
+            r#"
+#[doc(alias = "test alias")]
+trait Foo {
+    /// doc string
+    type Output;
+
+    #[must_use]
+    fn foo(&self);
+}
+struct S;
+impl Foo for S {
+    $0type Output;
+
+    fn foo(&self) {
+        todo!()
+    }
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_default_methods() {
+        check_assist(
+            add_missing_default_members,
+            r#"
+trait Foo {
+    type Output;
+
+    const CONST: usize = 42;
+
+    fn valid(some: u32) -> bool { false }
+    fn foo(some: u32) -> bool;
+}
+struct S;
+impl Foo for S { $0 }"#,
+            r#"
+trait Foo {
+    type Output;
+
+    const CONST: usize = 42;
+
+    fn valid(some: u32) -> bool { false }
+    fn foo(some: u32) -> bool;
+}
+struct S;
+impl Foo for S {
+    $0fn valid(some: u32) -> bool { false }
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_generic_single_default_parameter() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo<T = Self> {
+    fn bar(&self, other: &T);
+}
+
+struct S;
+impl Foo for S { $0 }"#,
+            r#"
+trait Foo<T = Self> {
+    fn bar(&self, other: &T);
+}
+
+struct S;
+impl Foo for S {
+    fn bar(&self, other: &Self) {
+        ${0:todo!()}
+    }
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_generic_default_parameter_is_second() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo<T1, T2 = Self> {
+    fn bar(&self, this: &T1, that: &T2);
+}
+
+struct S<T>;
+impl Foo<T> for S<T> { $0 }"#,
+            r#"
+trait Foo<T1, T2 = Self> {
+    fn bar(&self, this: &T1, that: &T2);
+}
+
+struct S<T>;
+impl Foo<T> for S<T> {
+    fn bar(&self, this: &T, that: &Self) {
+        ${0:todo!()}
+    }
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_assoc_type_bounds_are_removed() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Tr {
+    type Ty: Copy + 'static;
+}
+
+impl Tr for ()$0 {
+}"#,
+            r#"
+trait Tr {
+    type Ty: Copy + 'static;
+}
+
+impl Tr for () {
+    $0type Ty;
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_whitespace_fixup_preserves_bad_tokens() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Tr {
+    fn foo();
+}
+
+impl Tr for ()$0 {
+    +++
+}"#,
+            r#"
+trait Tr {
+    fn foo();
+}
+
+impl Tr for () {
+    fn foo() {
+        ${0:todo!()}
+    }
+    +++
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_whitespace_fixup_preserves_comments() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Tr {
+    fn foo();
+}
+
+impl Tr for ()$0 {
+    // very important
+}"#,
+            r#"
+trait Tr {
+    fn foo();
+}
+
+impl Tr for () {
+    fn foo() {
+        ${0:todo!()}
+    }
+    // very important
+}"#,
+        )
+    }
+
+    #[test]
+    fn weird_path() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Test {
+    fn foo(&self, x: crate)
+}
+impl Test for () {
+    $0
+}
+"#,
+            r#"
+trait Test {
+    fn foo(&self, x: crate)
+}
+impl Test for () {
+    fn foo(&self, x: crate) {
+        ${0:todo!()}
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn missing_generic_type() {
+        check_assist(
+            add_missing_impl_members,
+            r#"
+trait Foo<BAR> {
+    fn foo(&self, bar: BAR);
+}
+impl Foo for () {
+    $0
+}
+"#,
+            r#"
+trait Foo<BAR> {
+    fn foo(&self, bar: BAR);
+}
+impl Foo for () {
+    fn foo(&self, bar: BAR) {
+        ${0:todo!()}
+    }
+}
+"#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/add_turbo_fish.rs b/crates/ide_assists/src/handlers/add_turbo_fish.rs
new file mode 100644
index 000000000..8e9ea4fad
--- /dev/null
+++ b/crates/ide_assists/src/handlers/add_turbo_fish.rs
@@ -0,0 +1,164 @@
+use ide_db::defs::{Definition, NameRefClass};
+use syntax::{ast, AstNode, SyntaxKind, T};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind,
+};
+
+// Assist: add_turbo_fish
+//
+// Adds `::<_>` to a call of a generic method or function.
+//
+// ```
+// fn make<T>() -> T { todo!() }
+// fn main() {
+//     let x = make$0();
+// }
+// ```
+// ->
+// ```
+// fn make<T>() -> T { todo!() }
+// fn main() {
+//     let x = make::<${0:_}>();
+// }
+// ```
+pub(crate) fn add_turbo_fish(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let ident = ctx.find_token_syntax_at_offset(SyntaxKind::IDENT).or_else(|| {
+        let arg_list = ctx.find_node_at_offset::<ast::ArgList>()?;
+        if arg_list.args().count() > 0 {
+            return None;
+        }
+        mark::hit!(add_turbo_fish_after_call);
+        arg_list.l_paren_token()?.prev_token().filter(|it| it.kind() == SyntaxKind::IDENT)
+    })?;
+    let next_token = ident.next_token()?;
+    if next_token.kind() == T![::] {
+        mark::hit!(add_turbo_fish_one_fish_is_enough);
+        return None;
+    }
+    let name_ref = ast::NameRef::cast(ident.parent())?;
+    let def = match NameRefClass::classify(&ctx.sema, &name_ref)? {
+        NameRefClass::Definition(def) => def,
+        NameRefClass::ExternCrate(_) | NameRefClass::FieldShorthand { .. } => return None,
+    };
+    let fun = match def {
+        Definition::ModuleDef(hir::ModuleDef::Function(it)) => it,
+        _ => return None,
+    };
+    let generics = hir::GenericDef::Function(fun).params(ctx.sema.db);
+    if generics.is_empty() {
+        mark::hit!(add_turbo_fish_non_generic);
+        return None;
+    }
+    acc.add(
+        AssistId("add_turbo_fish", AssistKind::RefactorRewrite),
+        "Add `::<>`",
+        ident.text_range(),
+        |builder| match ctx.config.snippet_cap {
+            Some(cap) => builder.insert_snippet(cap, ident.text_range().end(), "::<${0:_}>"),
+            None => builder.insert(ident.text_range().end(), "::<_>"),
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+    use test_utils::mark;
+
+    #[test]
+    fn add_turbo_fish_function() {
+        check_assist(
+            add_turbo_fish,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    make$0();
+}
+"#,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    make::<${0:_}>();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn add_turbo_fish_after_call() {
+        mark::check!(add_turbo_fish_after_call);
+        check_assist(
+            add_turbo_fish,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    make()$0;
+}
+"#,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    make::<${0:_}>();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn add_turbo_fish_method() {
+        check_assist(
+            add_turbo_fish,
+            r#"
+struct S;
+impl S {
+    fn make<T>(&self) -> T {}
+}
+fn main() {
+    S.make$0();
+}
+"#,
+            r#"
+struct S;
+impl S {
+    fn make<T>(&self) -> T {}
+}
+fn main() {
+    S.make::<${0:_}>();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn add_turbo_fish_one_fish_is_enough() {
+        mark::check!(add_turbo_fish_one_fish_is_enough);
+        check_assist_not_applicable(
+            add_turbo_fish,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    make$0::<()>();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn add_turbo_fish_non_generic() {
+        mark::check!(add_turbo_fish_non_generic);
+        check_assist_not_applicable(
+            add_turbo_fish,
+            r#"
+fn make() -> () {}
+fn main() {
+    make$0();
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/apply_demorgan.rs b/crates/ide_assists/src/handlers/apply_demorgan.rs
new file mode 100644
index 000000000..ed4d11455
--- /dev/null
+++ b/crates/ide_assists/src/handlers/apply_demorgan.rs
@@ -0,0 +1,93 @@
+use syntax::ast::{self, AstNode};
+
+use crate::{utils::invert_boolean_expression, AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: apply_demorgan
+//
+// Apply https://en.wikipedia.org/wiki/De_Morgan%27s_laws[De Morgan's law].
+// This transforms expressions of the form `!l || !r` into `!(l && r)`.
+// This also works with `&&`. This assist can only be applied with the cursor
+// on either `||` or `&&`, with both operands being a negation of some kind.
+// This means something of the form `!x` or `x != y`.
+//
+// ```
+// fn main() {
+//     if x != 4 ||$0 !y {}
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     if !(x == 4 && y) {}
+// }
+// ```
+pub(crate) fn apply_demorgan(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let expr = ctx.find_node_at_offset::<ast::BinExpr>()?;
+    let op = expr.op_kind()?;
+    let op_range = expr.op_token()?.text_range();
+    let opposite_op = opposite_logic_op(op)?;
+    let cursor_in_range = op_range.contains_range(ctx.frange.range);
+    if !cursor_in_range {
+        return None;
+    }
+
+    let lhs = expr.lhs()?;
+    let lhs_range = lhs.syntax().text_range();
+    let not_lhs = invert_boolean_expression(lhs);
+
+    let rhs = expr.rhs()?;
+    let rhs_range = rhs.syntax().text_range();
+    let not_rhs = invert_boolean_expression(rhs);
+
+    acc.add(
+        AssistId("apply_demorgan", AssistKind::RefactorRewrite),
+        "Apply De Morgan's law",
+        op_range,
+        |edit| {
+            edit.replace(op_range, opposite_op);
+            edit.replace(lhs_range, format!("!({}", not_lhs.syntax().text()));
+            edit.replace(rhs_range, format!("{})", not_rhs.syntax().text()));
+        },
+    )
+}
+
+// Return the opposite text for a given logical operator, if it makes sense
+fn opposite_logic_op(kind: ast::BinOp) -> Option<&'static str> {
+    match kind {
+        ast::BinOp::BooleanOr => Some("&&"),
+        ast::BinOp::BooleanAnd => Some("||"),
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    #[test]
+    fn demorgan_turns_and_into_or() {
+        check_assist(apply_demorgan, "fn f() { !x &&$0 !x }", "fn f() { !(x || x) }")
+    }
+
+    #[test]
+    fn demorgan_turns_or_into_and() {
+        check_assist(apply_demorgan, "fn f() { !x ||$0 !x }", "fn f() { !(x && x) }")
+    }
+
+    #[test]
+    fn demorgan_removes_inequality() {
+        check_assist(apply_demorgan, "fn f() { x != x ||$0 !x }", "fn f() { !(x == x && x) }")
+    }
+
+    #[test]
+    fn demorgan_general_case() {
+        check_assist(apply_demorgan, "fn f() { x ||$0 x }", "fn f() { !(!x && !x) }")
+    }
+
+    #[test]
+    fn demorgan_doesnt_apply_with_cursor_not_on_op() {
+        check_assist_not_applicable(apply_demorgan, "fn f() { $0 !x || !x }")
+    }
+}
diff --git a/crates/ide_assists/src/handlers/auto_import.rs b/crates/ide_assists/src/handlers/auto_import.rs
new file mode 100644
index 000000000..e93901cb3
--- /dev/null
+++ b/crates/ide_assists/src/handlers/auto_import.rs
@@ -0,0 +1,970 @@
+use ide_db::helpers::{
+    import_assets::{ImportAssets, ImportCandidate},
+    insert_use::{insert_use, ImportScope},
+    mod_path_to_ast,
+};
+use syntax::{ast, AstNode, SyntaxNode};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists, GroupLabel};
+
+// Feature: Auto Import
+//
+// Using the `auto-import` assist it is possible to insert missing imports for unresolved items.
+// When inserting an import it will do so in a structured manner by keeping imports grouped,
+// separated by a newline in the following order:
+//
+// - `std` and `core`
+// - External Crates
+// - Current Crate, paths prefixed by `crate`
+// - Current Module, paths prefixed by `self`
+// - Super Module, paths prefixed by `super`
+//
+// Example:
+// ```rust
+// use std::fs::File;
+//
+// use itertools::Itertools;
+// use syntax::ast;
+//
+// use crate::utils::insert_use;
+//
+// use self::auto_import;
+//
+// use super::AssistContext;
+// ```
+//
+// .Merge Behaviour
+//
+// It is possible to configure how use-trees are merged with the `importMergeBehaviour` setting.
+// It has the following configurations:
+//
+// - `full`: This setting will cause auto-import to always completely merge use-trees that share the
+//  same path prefix while also merging inner trees that share the same path-prefix. This kind of
+//  nesting is only supported in Rust versions later than 1.24.
+// - `last`: This setting will cause auto-import to merge use-trees as long as the resulting tree
+//  will only contain a nesting of single segment paths at the very end.
+// - `none`: This setting will cause auto-import to never merge use-trees keeping them as simple
+//  paths.
+//
+// In `VS Code` the configuration for this is `rust-analyzer.assist.importMergeBehaviour`.
+//
+// .Import Prefix
+//
+// The style of imports in the same crate is configurable through the `importPrefix` setting.
+// It has the following configurations:
+//
+// - `by_crate`: This setting will force paths to be always absolute, starting with the `crate`
+//  prefix, unless the item is defined outside of the current crate.
+// - `by_self`: This setting will force paths that are relative to the current module to always
+//  start with `self`. This will result in paths that always start with either `crate`, `self`,
+//  `super` or an extern crate identifier.
+// - `plain`: This setting does not impose any restrictions in imports.
+//
+// In `VS Code` the configuration for this is `rust-analyzer.assist.importPrefix`.
+
+// Assist: auto_import
+//
+// If the name is unresolved, provides all possible imports for it.
+//
+// ```
+// fn main() {
+//     let map = HashMap$0::new();
+// }
+// # pub mod std { pub mod collections { pub struct HashMap { } } }
+// ```
+// ->
+// ```
+// use std::collections::HashMap;
+//
+// fn main() {
+//     let map = HashMap::new();
+// }
+// # pub mod std { pub mod collections { pub struct HashMap { } } }
+// ```
+pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let (import_assets, syntax_under_caret) = find_importable_node(ctx)?;
+    let proposed_imports =
+        import_assets.search_for_imports(&ctx.sema, ctx.config.insert_use.prefix_kind);
+    if proposed_imports.is_empty() {
+        return None;
+    }
+
+    let range = ctx.sema.original_range(&syntax_under_caret).range;
+    let group = import_group_message(import_assets.import_candidate());
+    let scope = ImportScope::find_insert_use_container(&syntax_under_caret, &ctx.sema)?;
+    for (import, _) in proposed_imports {
+        acc.add_group(
+            &group,
+            AssistId("auto_import", AssistKind::QuickFix),
+            format!("Import `{}`", &import),
+            range,
+            |builder| {
+                let rewriter =
+                    insert_use(&scope, mod_path_to_ast(&import), ctx.config.insert_use.merge);
+                builder.rewrite(rewriter);
+            },
+        );
+    }
+    Some(())
+}
+
+pub(super) fn find_importable_node(ctx: &AssistContext) -> Option<(ImportAssets, SyntaxNode)> {
+    if let Some(path_under_caret) = ctx.find_node_at_offset_with_descend::<ast::Path>() {
+        ImportAssets::for_exact_path(&path_under_caret, &ctx.sema)
+            .zip(Some(path_under_caret.syntax().clone()))
+    } else if let Some(method_under_caret) =
+        ctx.find_node_at_offset_with_descend::<ast::MethodCallExpr>()
+    {
+        ImportAssets::for_method_call(&method_under_caret, &ctx.sema)
+            .zip(Some(method_under_caret.syntax().clone()))
+    } else {
+        None
+    }
+}
+
+fn import_group_message(import_candidate: &ImportCandidate) -> GroupLabel {
+    let name = match import_candidate {
+        ImportCandidate::Path(candidate) => format!("Import {}", candidate.name.text()),
+        ImportCandidate::TraitAssocItem(candidate) => {
+            format!("Import a trait for item {}", candidate.name.text())
+        }
+        ImportCandidate::TraitMethod(candidate) => {
+            format!("Import a trait for method {}", candidate.name.text())
+        }
+    };
+    GroupLabel(name)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    #[test]
+    fn applicable_when_found_an_import_partial() {
+        check_assist(
+            auto_import,
+            r"
+            mod std {
+                pub mod fmt {
+                    pub struct Formatter;
+                }
+            }
+
+            use std::fmt;
+
+            $0Formatter
+            ",
+            r"
+            mod std {
+                pub mod fmt {
+                    pub struct Formatter;
+                }
+            }
+
+            use std::fmt::{self, Formatter};
+
+            Formatter
+            ",
+        );
+    }
+
+    #[test]
+    fn applicable_when_found_an_import() {
+        check_assist(
+            auto_import,
+            r"
+            $0PubStruct
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            use PubMod::PubStruct;
+
+            PubStruct
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn applicable_when_found_an_import_in_macros() {
+        check_assist(
+            auto_import,
+            r"
+            macro_rules! foo {
+                ($i:ident) => { fn foo(a: $i) {} }
+            }
+            foo!(Pub$0Struct);
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            use PubMod::PubStruct;
+
+            macro_rules! foo {
+                ($i:ident) => { fn foo(a: $i) {} }
+            }
+            foo!(PubStruct);
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn auto_imports_are_merged() {
+        check_assist(
+            auto_import,
+            r"
+            use PubMod::PubStruct1;
+
+            struct Test {
+                test: Pub$0Struct2<u8>,
+            }
+
+            pub mod PubMod {
+                pub struct PubStruct1;
+                pub struct PubStruct2<T> {
+                    _t: T,
+                }
+            }
+            ",
+            r"
+            use PubMod::{PubStruct1, PubStruct2};
+
+            struct Test {
+                test: PubStruct2<u8>,
+            }
+
+            pub mod PubMod {
+                pub struct PubStruct1;
+                pub struct PubStruct2<T> {
+                    _t: T,
+                }
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn applicable_when_found_multiple_imports() {
+        check_assist(
+            auto_import,
+            r"
+            PubSt$0ruct
+
+            pub mod PubMod1 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod2 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod3 {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            use PubMod3::PubStruct;
+
+            PubStruct
+
+            pub mod PubMod1 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod2 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod3 {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_already_imported_types() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            use PubMod::PubStruct;
+
+            PubStruct$0
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_types_with_private_paths() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            PrivateStruct$0
+
+            pub mod PubMod {
+                struct PrivateStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_when_no_imports_found() {
+        check_assist_not_applicable(
+            auto_import,
+            "
+            PubStruct$0",
+        );
+    }
+
+    #[test]
+    fn not_applicable_in_import_statements() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            use PubStruct$0;
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }",
+        );
+    }
+
+    #[test]
+    fn function_import() {
+        check_assist(
+            auto_import,
+            r"
+            test_function$0
+
+            pub mod PubMod {
+                pub fn test_function() {};
+            }
+            ",
+            r"
+            use PubMod::test_function;
+
+            test_function
+
+            pub mod PubMod {
+                pub fn test_function() {};
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn macro_import() {
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:crate_with_macro
+#[macro_export]
+macro_rules! foo {
+    () => ()
+}
+
+//- /main.rs crate:main deps:crate_with_macro
+fn main() {
+    foo$0
+}
+",
+            r"use crate_with_macro::foo;
+
+fn main() {
+    foo
+}
+",
+        );
+    }
+
+    #[test]
+    fn auto_import_target() {
+        check_assist_target(
+            auto_import,
+            r"
+            struct AssistInfo {
+                group_label: Option<$0GroupLabel>,
+            }
+
+            mod m { pub struct GroupLabel; }
+            ",
+            "GroupLabel",
+        )
+    }
+
+    #[test]
+    fn not_applicable_when_path_start_is_imported() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            pub mod mod1 {
+                pub mod mod2 {
+                    pub mod mod3 {
+                        pub struct TestStruct;
+                    }
+                }
+            }
+
+            use mod1::mod2;
+            fn main() {
+                mod2::mod3::TestStruct$0
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_function() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            pub mod test_mod {
+                pub fn test_function() {}
+            }
+
+            use test_mod::test_function;
+            fn main() {
+                test_function$0
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_struct_function() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    pub fn test_function() {}
+                }
+            }
+
+            fn main() {
+                TestStruct::test_function$0
+            }
+            ",
+            r"
+            use test_mod::TestStruct;
+
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    pub fn test_function() {}
+                }
+            }
+
+            fn main() {
+                TestStruct::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_struct_const() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                TestStruct::TEST_CONST$0
+            }
+            ",
+            r"
+            use test_mod::TestStruct;
+
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                TestStruct::TEST_CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_trait_function() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::test_function$0
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_function() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub trait TestTrait2 {
+                    fn test_function();
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    fn test_function() {}
+                }
+                impl TestTrait for TestEnum {
+                    fn test_function() {}
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                test_mod::TestEnum::test_function$0;
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn associated_trait_const() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::TEST_CONST$0
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::TEST_CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_const() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub trait TestTrait2 {
+                    const TEST_CONST: f64;
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    const TEST_CONST: f64 = 42.0;
+                }
+                impl TestTrait for TestEnum {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                test_mod::TestEnum::TEST_CONST$0;
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn trait_method() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_meth$0od()
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_method()
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn trait_method_cross_crate() {
+        check_assist(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_meth$0od()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+            ",
+            r"
+            use dep::test_mod::TestTrait;
+
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_method()
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_fn_cross_crate() {
+        check_assist(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                dep::test_mod::TestStruct::test_func$0tion
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+            ",
+            r"
+            use dep::test_mod::TestTrait;
+
+            fn main() {
+                dep::test_mod::TestStruct::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_const_cross_crate() {
+        check_assist(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                dep::test_mod::TestStruct::CONST$0
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    const CONST: bool;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const CONST: bool = true;
+                }
+            }
+            ",
+            r"
+            use dep::test_mod::TestTrait;
+
+            fn main() {
+                dep::test_mod::TestStruct::CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_fn_as_method_cross_crate() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_func$0tion()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn private_trait_cross_crate() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_meth$0od()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_method() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub trait TestTrait2 {
+                    fn test_method(&self);
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    fn test_method(&self) {}
+                }
+                impl TestTrait for TestEnum {
+                    fn test_method(&self) {}
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                let one = test_mod::TestEnum::One;
+                one.test$0_method();
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn dep_import() {
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:dep
+pub struct Struct;
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    Struct$0
+}
+",
+            r"use dep::Struct;
+
+fn main() {
+    Struct
+}
+",
+        );
+    }
+
+    #[test]
+    fn whole_segment() {
+        // Tests that only imports whose last segment matches the identifier get suggested.
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:dep
+pub mod fmt {
+    pub trait Display {}
+}
+
+pub fn panic_fmt() {}
+
+//- /main.rs crate:main deps:dep
+struct S;
+
+impl f$0mt::Display for S {}
+",
+            r"use dep::fmt;
+
+struct S;
+
+impl fmt::Display for S {}
+",
+        );
+    }
+
+    #[test]
+    fn macro_generated() {
+        // Tests that macro-generated items are suggested from external crates.
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:dep
+macro_rules! mac {
+    () => {
+        pub struct Cheese;
+    };
+}
+
+mac!();
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    Cheese$0;
+}
+",
+            r"use dep::Cheese;
+
+fn main() {
+    Cheese;
+}
+",
+        );
+    }
+
+    #[test]
+    fn casing() {
+        // Tests that differently cased names don't interfere and we only suggest the matching one.
+        check_assist(
+            auto_import,
+            r"
+//- /lib.rs crate:dep
+pub struct FMT;
+pub struct fmt;
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    FMT$0;
+}
+",
+            r"use dep::FMT;
+
+fn main() {
+    FMT;
+}
+",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/change_visibility.rs b/crates/ide_assists/src/handlers/change_visibility.rs
new file mode 100644
index 000000000..ac8c44124
--- /dev/null
+++ b/crates/ide_assists/src/handlers/change_visibility.rs
@@ -0,0 +1,212 @@
+use syntax::{
+    ast::{self, NameOwner, VisibilityOwner},
+    AstNode,
+    SyntaxKind::{CONST, ENUM, FN, MODULE, STATIC, STRUCT, TRAIT, TYPE_ALIAS, VISIBILITY},
+    T,
+};
+use test_utils::mark;
+
+use crate::{utils::vis_offset, AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: change_visibility
+//
+// Adds or changes existing visibility specifier.
+//
+// ```
+// $0fn frobnicate() {}
+// ```
+// ->
+// ```
+// pub(crate) fn frobnicate() {}
+// ```
+pub(crate) fn change_visibility(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    if let Some(vis) = ctx.find_node_at_offset::<ast::Visibility>() {
+        return change_vis(acc, vis);
+    }
+    add_vis(acc, ctx)
+}
+
+fn add_vis(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let item_keyword = ctx.token_at_offset().find(|leaf| {
+        matches!(
+            leaf.kind(),
+            T![const]
+                | T![static]
+                | T![fn]
+                | T![mod]
+                | T![struct]
+                | T![enum]
+                | T![trait]
+                | T![type]
+        )
+    });
+
+    let (offset, target) = if let Some(keyword) = item_keyword {
+        let parent = keyword.parent();
+        let def_kws = vec![CONST, STATIC, TYPE_ALIAS, FN, MODULE, STRUCT, ENUM, TRAIT];
+        // Parent is not a definition, can't add visibility
+        if !def_kws.iter().any(|&def_kw| def_kw == parent.kind()) {
+            return None;
+        }
+        // Already have visibility, do nothing
+        if parent.children().any(|child| child.kind() == VISIBILITY) {
+            return None;
+        }
+        (vis_offset(&parent), keyword.text_range())
+    } else if let Some(field_name) = ctx.find_node_at_offset::<ast::Name>() {
+        let field = field_name.syntax().ancestors().find_map(ast::RecordField::cast)?;
+        if field.name()? != field_name {
+            mark::hit!(change_visibility_field_false_positive);
+            return None;
+        }
+        if field.visibility().is_some() {
+            return None;
+        }
+        (vis_offset(field.syntax()), field_name.syntax().text_range())
+    } else if let Some(field) = ctx.find_node_at_offset::<ast::TupleField>() {
+        if field.visibility().is_some() {
+            return None;
+        }
+        (vis_offset(field.syntax()), field.syntax().text_range())
+    } else {
+        return None;
+    };
+
+    acc.add(
+        AssistId("change_visibility", AssistKind::RefactorRewrite),
+        "Change visibility to pub(crate)",
+        target,
+        |edit| {
+            edit.insert(offset, "pub(crate) ");
+        },
+    )
+}
+
+fn change_vis(acc: &mut Assists, vis: ast::Visibility) -> Option<()> {
+    if vis.syntax().text() == "pub" {
+        let target = vis.syntax().text_range();
+        return acc.add(
+            AssistId("change_visibility", AssistKind::RefactorRewrite),
+            "Change Visibility to pub(crate)",
+            target,
+            |edit| {
+                edit.replace(vis.syntax().text_range(), "pub(crate)");
+            },
+        );
+    }
+    if vis.syntax().text() == "pub(crate)" {
+        let target = vis.syntax().text_range();
+        return acc.add(
+            AssistId("change_visibility", AssistKind::RefactorRewrite),
+            "Change visibility to pub",
+            target,
+            |edit| {
+                edit.replace(vis.syntax().text_range(), "pub");
+            },
+        );
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn change_visibility_adds_pub_crate_to_items() {
+        check_assist(change_visibility, "$0fn foo() {}", "pub(crate) fn foo() {}");
+        check_assist(change_visibility, "f$0n foo() {}", "pub(crate) fn foo() {}");
+        check_assist(change_visibility, "$0struct Foo {}", "pub(crate) struct Foo {}");
+        check_assist(change_visibility, "$0mod foo {}", "pub(crate) mod foo {}");
+        check_assist(change_visibility, "$0trait Foo {}", "pub(crate) trait Foo {}");
+        check_assist(change_visibility, "m$0od {}", "pub(crate) mod {}");
+        check_assist(change_visibility, "unsafe f$0n foo() {}", "pub(crate) unsafe fn foo() {}");
+    }
+
+    #[test]
+    fn change_visibility_works_with_struct_fields() {
+        check_assist(
+            change_visibility,
+            r"struct S { $0field: u32 }",
+            r"struct S { pub(crate) field: u32 }",
+        );
+        check_assist(change_visibility, r"struct S ( $0u32 )", r"struct S ( pub(crate) u32 )");
+    }
+
+    #[test]
+    fn change_visibility_field_false_positive() {
+        mark::check!(change_visibility_field_false_positive);
+        check_assist_not_applicable(
+            change_visibility,
+            r"struct S { field: [(); { let $0x = ();}] }",
+        )
+    }
+
+    #[test]
+    fn change_visibility_pub_to_pub_crate() {
+        check_assist(change_visibility, "$0pub fn foo() {}", "pub(crate) fn foo() {}")
+    }
+
+    #[test]
+    fn change_visibility_pub_crate_to_pub() {
+        check_assist(change_visibility, "$0pub(crate) fn foo() {}", "pub fn foo() {}")
+    }
+
+    #[test]
+    fn change_visibility_const() {
+        check_assist(change_visibility, "$0const FOO = 3u8;", "pub(crate) const FOO = 3u8;");
+    }
+
+    #[test]
+    fn change_visibility_static() {
+        check_assist(change_visibility, "$0static FOO = 3u8;", "pub(crate) static FOO = 3u8;");
+    }
+
+    #[test]
+    fn change_visibility_type_alias() {
+        check_assist(change_visibility, "$0type T = ();", "pub(crate) type T = ();");
+    }
+
+    #[test]
+    fn change_visibility_handles_comment_attrs() {
+        check_assist(
+            change_visibility,
+            r"
+            /// docs
+
+            // comments
+
+            #[derive(Debug)]
+            $0struct Foo;
+            ",
+            r"
+            /// docs
+
+            // comments
+
+            #[derive(Debug)]
+            pub(crate) struct Foo;
+            ",
+        )
+    }
+
+    #[test]
+    fn not_applicable_for_enum_variants() {
+        check_assist_not_applicable(
+            change_visibility,
+            r"mod foo { pub enum Foo {Foo1} }
+              fn main() { foo::Foo::Foo1$0 } ",
+        );
+    }
+
+    #[test]
+    fn change_visibility_target() {
+        check_assist_target(change_visibility, "$0fn foo() {}", "fn");
+        check_assist_target(change_visibility, "pub(crate)$0 fn foo() {}", "pub(crate)");
+        check_assist_target(change_visibility, "struct S { $0field: u32 }", "field");
+    }
+}
diff --git a/crates/ide_assists/src/handlers/convert_integer_literal.rs b/crates/ide_assists/src/handlers/convert_integer_literal.rs
new file mode 100644
index 000000000..a8a819cfc
--- /dev/null
+++ b/crates/ide_assists/src/handlers/convert_integer_literal.rs
@@ -0,0 +1,268 @@
+use syntax::{ast, ast::Radix, AstToken};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists, GroupLabel};
+
+// Assist: convert_integer_literal
+//
+// Converts the base of integer literals to other bases.
+//
+// ```
+// const _: i32 = 10$0;
+// ```
+// ->
+// ```
+// const _: i32 = 0b1010;
+// ```
+pub(crate) fn convert_integer_literal(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let literal = ctx.find_node_at_offset::<ast::Literal>()?;
+    let literal = match literal.kind() {
+        ast::LiteralKind::IntNumber(it) => it,
+        _ => return None,
+    };
+    let radix = literal.radix();
+    let value = literal.value()?;
+    let suffix = literal.suffix();
+
+    let range = literal.syntax().text_range();
+    let group_id = GroupLabel("Convert integer base".into());
+
+    for &target_radix in Radix::ALL {
+        if target_radix == radix {
+            continue;
+        }
+
+        let mut converted = match target_radix {
+            Radix::Binary => format!("0b{:b}", value),
+            Radix::Octal => format!("0o{:o}", value),
+            Radix::Decimal => value.to_string(),
+            Radix::Hexadecimal => format!("0x{:X}", value),
+        };
+
+        let label = format!("Convert {} to {}{}", literal, converted, suffix.unwrap_or_default());
+
+        // Appends the type suffix back into the new literal if it exists.
+        if let Some(suffix) = suffix {
+            converted.push_str(suffix);
+        }
+
+        acc.add_group(
+            &group_id,
+            AssistId("convert_integer_literal", AssistKind::RefactorInline),
+            label,
+            range,
+            |builder| builder.replace(range, converted),
+        );
+    }
+
+    Some(())
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist_by_label, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn binary_target() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0b1010$0;", "0b1010");
+    }
+
+    #[test]
+    fn octal_target() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0o12$0;", "0o12");
+    }
+
+    #[test]
+    fn decimal_target() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 10$0;", "10");
+    }
+
+    #[test]
+    fn hexadecimal_target() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0xA$0;", "0xA");
+    }
+
+    #[test]
+    fn binary_target_with_underscores() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0b10_10$0;", "0b10_10");
+    }
+
+    #[test]
+    fn octal_target_with_underscores() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0o1_2$0;", "0o1_2");
+    }
+
+    #[test]
+    fn decimal_target_with_underscores() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 1_0$0;", "1_0");
+    }
+
+    #[test]
+    fn hexadecimal_target_with_underscores() {
+        check_assist_target(convert_integer_literal, "const _: i32 = 0x_A$0;", "0x_A");
+    }
+
+    #[test]
+    fn convert_decimal_integer() {
+        let before = "const _: i32 = 1000$0;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1111101000;",
+            "Convert 1000 to 0b1111101000",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o1750;",
+            "Convert 1000 to 0o1750",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0x3E8;",
+            "Convert 1000 to 0x3E8",
+        );
+    }
+
+    #[test]
+    fn convert_hexadecimal_integer() {
+        let before = "const _: i32 = 0xFF$0;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111;",
+            "Convert 0xFF to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377;",
+            "Convert 0xFF to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0xFF to 255",
+        );
+    }
+
+    #[test]
+    fn convert_binary_integer() {
+        let before = "const _: i32 = 0b11111111$0;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o377;",
+            "Convert 0b11111111 to 0o377",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0b11111111 to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFF;",
+            "Convert 0b11111111 to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_octal_integer() {
+        let before = "const _: i32 = 0o377$0;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b11111111;",
+            "Convert 0o377 to 0b11111111",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 255;",
+            "Convert 0o377 to 255",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0xFF;",
+            "Convert 0o377 to 0xFF",
+        );
+    }
+
+    #[test]
+    fn convert_integer_with_underscores() {
+        let before = "const _: i32 = 1_00_0$0;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1111101000;",
+            "Convert 1_00_0 to 0b1111101000",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o1750;",
+            "Convert 1_00_0 to 0o1750",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0x3E8;",
+            "Convert 1_00_0 to 0x3E8",
+        );
+    }
+
+    #[test]
+    fn convert_integer_with_suffix() {
+        let before = "const _: i32 = 1000i32$0;";
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0b1111101000i32;",
+            "Convert 1000i32 to 0b1111101000i32",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0o1750i32;",
+            "Convert 1000i32 to 0o1750i32",
+        );
+
+        check_assist_by_label(
+            convert_integer_literal,
+            before,
+            "const _: i32 = 0x3E8i32;",
+            "Convert 1000i32 to 0x3E8i32",
+        );
+    }
+
+    #[test]
+    fn convert_overflowing_literal() {
+        let before = "const _: i32 =
+            111111111111111111111111111111111111111111111111111111111111111111111111$0;";
+        check_assist_not_applicable(convert_integer_literal, before);
+    }
+}
diff --git a/crates/ide_assists/src/handlers/early_return.rs b/crates/ide_assists/src/handlers/early_return.rs
new file mode 100644
index 000000000..6b87c3c05
--- /dev/null
+++ b/crates/ide_assists/src/handlers/early_return.rs
@@ -0,0 +1,515 @@
+use std::{iter::once, ops::RangeInclusive};
+
+use syntax::{
+    algo::replace_children,
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+        make,
+    },
+    AstNode,
+    SyntaxKind::{FN, LOOP_EXPR, L_CURLY, R_CURLY, WHILE_EXPR, WHITESPACE},
+    SyntaxNode,
+};
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    utils::invert_boolean_expression,
+    AssistId, AssistKind,
+};
+
+// Assist: convert_to_guarded_return
+//
+// Replace a large conditional with a guarded return.
+//
+// ```
+// fn main() {
+//     $0if cond {
+//         foo();
+//         bar();
+//     }
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     if !cond {
+//         return;
+//     }
+//     foo();
+//     bar();
+// }
+// ```
+pub(crate) fn convert_to_guarded_return(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let if_expr: ast::IfExpr = ctx.find_node_at_offset()?;
+    if if_expr.else_branch().is_some() {
+        return None;
+    }
+
+    let cond = if_expr.condition()?;
+
+    // Check if there is an IfLet that we can handle.
+    let if_let_pat = match cond.pat() {
+        None => None, // No IfLet, supported.
+        Some(ast::Pat::TupleStructPat(pat)) if pat.fields().count() == 1 => {
+            let path = pat.path()?;
+            match path.qualifier() {
+                None => {
+                    let bound_ident = pat.fields().next().unwrap();
+                    Some((path, bound_ident))
+                }
+                Some(_) => return None,
+            }
+        }
+        Some(_) => return None, // Unsupported IfLet.
+    };
+
+    let cond_expr = cond.expr()?;
+    let then_block = if_expr.then_branch()?;
+
+    let parent_block = if_expr.syntax().parent()?.ancestors().find_map(ast::BlockExpr::cast)?;
+
+    if parent_block.tail_expr()? != if_expr.clone().into() {
+        return None;
+    }
+
+    // check for early return and continue
+    let first_in_then_block = then_block.syntax().first_child()?;
+    if ast::ReturnExpr::can_cast(first_in_then_block.kind())
+        || ast::ContinueExpr::can_cast(first_in_then_block.kind())
+        || first_in_then_block
+            .children()
+            .any(|x| ast::ReturnExpr::can_cast(x.kind()) || ast::ContinueExpr::can_cast(x.kind()))
+    {
+        return None;
+    }
+
+    let parent_container = parent_block.syntax().parent()?;
+
+    let early_expression: ast::Expr = match parent_container.kind() {
+        WHILE_EXPR | LOOP_EXPR => make::expr_continue(),
+        FN => make::expr_return(None),
+        _ => return None,
+    };
+
+    if then_block.syntax().first_child_or_token().map(|t| t.kind() == L_CURLY).is_none() {
+        return None;
+    }
+
+    then_block.syntax().last_child_or_token().filter(|t| t.kind() == R_CURLY)?;
+
+    let target = if_expr.syntax().text_range();
+    acc.add(
+        AssistId("convert_to_guarded_return", AssistKind::RefactorRewrite),
+        "Convert to guarded return",
+        target,
+        |edit| {
+            let if_indent_level = IndentLevel::from_node(&if_expr.syntax());
+            let new_block = match if_let_pat {
+                None => {
+                    // If.
+                    let new_expr = {
+                        let then_branch =
+                            make::block_expr(once(make::expr_stmt(early_expression).into()), None);
+                        let cond = invert_boolean_expression(cond_expr);
+                        make::expr_if(make::condition(cond, None), then_branch, None)
+                            .indent(if_indent_level)
+                    };
+                    replace(new_expr.syntax(), &then_block, &parent_block, &if_expr)
+                }
+                Some((path, bound_ident)) => {
+                    // If-let.
+                    let match_expr = {
+                        let happy_arm = {
+                            let pat = make::tuple_struct_pat(
+                                path,
+                                once(make::ident_pat(make::name("it")).into()),
+                            );
+                            let expr = {
+                                let name_ref = make::name_ref("it");
+                                let segment = make::path_segment(name_ref);
+                                let path = make::path_unqualified(segment);
+                                make::expr_path(path)
+                            };
+                            make::match_arm(once(pat.into()), expr)
+                        };
+
+                        let sad_arm = make::match_arm(
+                            // FIXME: would be cool to use `None` or `Err(_)` if appropriate
+                            once(make::wildcard_pat().into()),
+                            early_expression,
+                        );
+
+                        make::expr_match(cond_expr, make::match_arm_list(vec![happy_arm, sad_arm]))
+                    };
+
+                    let let_stmt = make::let_stmt(
+                        make::ident_pat(make::name(&bound_ident.syntax().to_string())).into(),
+                        Some(match_expr),
+                    );
+                    let let_stmt = let_stmt.indent(if_indent_level);
+                    replace(let_stmt.syntax(), &then_block, &parent_block, &if_expr)
+                }
+            };
+            edit.replace_ast(parent_block, ast::BlockExpr::cast(new_block).unwrap());
+
+            fn replace(
+                new_expr: &SyntaxNode,
+                then_block: &ast::BlockExpr,
+                parent_block: &ast::BlockExpr,
+                if_expr: &ast::IfExpr,
+            ) -> SyntaxNode {
+                let then_block_items = then_block.dedent(IndentLevel(1));
+                let end_of_then = then_block_items.syntax().last_child_or_token().unwrap();
+                let end_of_then =
+                    if end_of_then.prev_sibling_or_token().map(|n| n.kind()) == Some(WHITESPACE) {
+                        end_of_then.prev_sibling_or_token().unwrap()
+                    } else {
+                        end_of_then
+                    };
+                let mut then_statements = new_expr.children_with_tokens().chain(
+                    then_block_items
+                        .syntax()
+                        .children_with_tokens()
+                        .skip(1)
+                        .take_while(|i| *i != end_of_then),
+                );
+                replace_children(
+                    &parent_block.syntax(),
+                    RangeInclusive::new(
+                        if_expr.clone().syntax().clone().into(),
+                        if_expr.syntax().clone().into(),
+                    ),
+                    &mut then_statements,
+                )
+            }
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn convert_inside_fn() {
+        check_assist(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                bar();
+                if$0 true {
+                    foo();
+
+                    //comment
+                    bar();
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                bar();
+                if !true {
+                    return;
+                }
+                foo();
+
+                //comment
+                bar();
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn convert_let_inside_fn() {
+        check_assist(
+            convert_to_guarded_return,
+            r#"
+            fn main(n: Option<String>) {
+                bar();
+                if$0 let Some(n) = n {
+                    foo(n);
+
+                    //comment
+                    bar();
+                }
+            }
+            "#,
+            r#"
+            fn main(n: Option<String>) {
+                bar();
+                let n = match n {
+                    Some(it) => it,
+                    _ => return,
+                };
+                foo(n);
+
+                //comment
+                bar();
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn convert_if_let_result() {
+        check_assist(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                if$0 let Ok(x) = Err(92) {
+                    foo(x);
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                let x = match Err(92) {
+                    Ok(it) => it,
+                    _ => return,
+                };
+                foo(x);
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn convert_let_ok_inside_fn() {
+        check_assist(
+            convert_to_guarded_return,
+            r#"
+            fn main(n: Option<String>) {
+                bar();
+                if$0 let Ok(n) = n {
+                    foo(n);
+
+                    //comment
+                    bar();
+                }
+            }
+            "#,
+            r#"
+            fn main(n: Option<String>) {
+                bar();
+                let n = match n {
+                    Ok(it) => it,
+                    _ => return,
+                };
+                foo(n);
+
+                //comment
+                bar();
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn convert_inside_while() {
+        check_assist(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                while true {
+                    if$0 true {
+                        foo();
+                        bar();
+                    }
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                while true {
+                    if !true {
+                        continue;
+                    }
+                    foo();
+                    bar();
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn convert_let_inside_while() {
+        check_assist(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                while true {
+                    if$0 let Some(n) = n {
+                        foo(n);
+                        bar();
+                    }
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                while true {
+                    let n = match n {
+                        Some(it) => it,
+                        _ => continue,
+                    };
+                    foo(n);
+                    bar();
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn convert_inside_loop() {
+        check_assist(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                loop {
+                    if$0 true {
+                        foo();
+                        bar();
+                    }
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                loop {
+                    if !true {
+                        continue;
+                    }
+                    foo();
+                    bar();
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn convert_let_inside_loop() {
+        check_assist(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                loop {
+                    if$0 let Some(n) = n {
+                        foo(n);
+                        bar();
+                    }
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                loop {
+                    let n = match n {
+                        Some(it) => it,
+                        _ => continue,
+                    };
+                    foo(n);
+                    bar();
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn ignore_already_converted_if() {
+        check_assist_not_applicable(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                if$0 true {
+                    return;
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn ignore_already_converted_loop() {
+        check_assist_not_applicable(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                loop {
+                    if$0 true {
+                        continue;
+                    }
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn ignore_return() {
+        check_assist_not_applicable(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                if$0 true {
+                    return
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn ignore_else_branch() {
+        check_assist_not_applicable(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                if$0 true {
+                    foo();
+                } else {
+                    bar()
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn ignore_statements_aftert_if() {
+        check_assist_not_applicable(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                if$0 true {
+                    foo();
+                }
+                bar();
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn ignore_statements_inside_if() {
+        check_assist_not_applicable(
+            convert_to_guarded_return,
+            r#"
+            fn main() {
+                if false {
+                    if$0 true {
+                        foo();
+                    }
+                }
+            }
+            "#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/expand_glob_import.rs b/crates/ide_assists/src/handlers/expand_glob_import.rs
new file mode 100644
index 000000000..5fe617ba4
--- /dev/null
+++ b/crates/ide_assists/src/handlers/expand_glob_import.rs
@@ -0,0 +1,907 @@
+use either::Either;
+use hir::{AssocItem, MacroDef, Module, ModuleDef, Name, PathResolution, ScopeDef};
+use ide_db::{
+    defs::{Definition, NameRefClass},
+    search::SearchScope,
+};
+use syntax::{
+    algo::SyntaxRewriter,
+    ast::{self, make},
+    AstNode, Direction, SyntaxNode, SyntaxToken, T,
+};
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind,
+};
+
+// Assist: expand_glob_import
+//
+// Expands glob imports.
+//
+// ```
+// mod foo {
+//     pub struct Bar;
+//     pub struct Baz;
+// }
+//
+// use foo::*$0;
+//
+// fn qux(bar: Bar, baz: Baz) {}
+// ```
+// ->
+// ```
+// mod foo {
+//     pub struct Bar;
+//     pub struct Baz;
+// }
+//
+// use foo::{Baz, Bar};
+//
+// fn qux(bar: Bar, baz: Baz) {}
+// ```
+pub(crate) fn expand_glob_import(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let star = ctx.find_token_syntax_at_offset(T![*])?;
+    let (parent, mod_path) = find_parent_and_path(&star)?;
+    let target_module = match ctx.sema.resolve_path(&mod_path)? {
+        PathResolution::Def(ModuleDef::Module(it)) => it,
+        _ => return None,
+    };
+
+    let current_scope = ctx.sema.scope(&star.parent());
+    let current_module = current_scope.module()?;
+
+    let refs_in_target = find_refs_in_mod(ctx, target_module, Some(current_module))?;
+    let imported_defs = find_imported_defs(ctx, star)?;
+    let names_to_import = find_names_to_import(ctx, refs_in_target, imported_defs);
+
+    let target = parent.clone().either(|n| n.syntax().clone(), |n| n.syntax().clone());
+    acc.add(
+        AssistId("expand_glob_import", AssistKind::RefactorRewrite),
+        "Expand glob import",
+        target.text_range(),
+        |builder| {
+            let mut rewriter = SyntaxRewriter::default();
+            replace_ast(&mut rewriter, parent, mod_path, names_to_import);
+            builder.rewrite(rewriter);
+        },
+    )
+}
+
+fn find_parent_and_path(
+    star: &SyntaxToken,
+) -> Option<(Either<ast::UseTree, ast::UseTreeList>, ast::Path)> {
+    return star.ancestors().find_map(|n| {
+        find_use_tree_list(n.clone())
+            .and_then(|(u, p)| Some((Either::Right(u), p)))
+            .or_else(|| find_use_tree(n).and_then(|(u, p)| Some((Either::Left(u), p))))
+    });
+
+    fn find_use_tree_list(n: SyntaxNode) -> Option<(ast::UseTreeList, ast::Path)> {
+        let use_tree_list = ast::UseTreeList::cast(n)?;
+        let path = use_tree_list.parent_use_tree().path()?;
+        Some((use_tree_list, path))
+    }
+
+    fn find_use_tree(n: SyntaxNode) -> Option<(ast::UseTree, ast::Path)> {
+        let use_tree = ast::UseTree::cast(n)?;
+        let path = use_tree.path()?;
+        Some((use_tree, path))
+    }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+enum Def {
+    ModuleDef(ModuleDef),
+    MacroDef(MacroDef),
+}
+
+impl Def {
+    fn is_referenced_in(&self, ctx: &AssistContext) -> bool {
+        let def = match self {
+            Def::ModuleDef(def) => Definition::ModuleDef(*def),
+            Def::MacroDef(def) => Definition::Macro(*def),
+        };
+
+        let search_scope = SearchScope::single_file(ctx.frange.file_id);
+        def.usages(&ctx.sema).in_scope(search_scope).at_least_one()
+    }
+}
+
+#[derive(Debug, Clone)]
+struct Ref {
+    // could be alias
+    visible_name: Name,
+    def: Def,
+}
+
+impl Ref {
+    fn from_scope_def(name: Name, scope_def: ScopeDef) -> Option<Self> {
+        match scope_def {
+            ScopeDef::ModuleDef(def) => Some(Ref { visible_name: name, def: Def::ModuleDef(def) }),
+            ScopeDef::MacroDef(def) => Some(Ref { visible_name: name, def: Def::MacroDef(def) }),
+            _ => None,
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+struct Refs(Vec<Ref>);
+
+impl Refs {
+    fn used_refs(&self, ctx: &AssistContext) -> Refs {
+        Refs(
+            self.0
+                .clone()
+                .into_iter()
+                .filter(|r| {
+                    if let Def::ModuleDef(ModuleDef::Trait(tr)) = r.def {
+                        if tr
+                            .items(ctx.db())
+                            .into_iter()
+                            .find(|ai| {
+                                if let AssocItem::Function(f) = *ai {
+                                    Def::ModuleDef(ModuleDef::Function(f)).is_referenced_in(ctx)
+                                } else {
+                                    false
+                                }
+                            })
+                            .is_some()
+                        {
+                            return true;
+                        }
+                    }
+
+                    r.def.is_referenced_in(ctx)
+                })
+                .collect(),
+        )
+    }
+
+    fn filter_out_by_defs(&self, defs: Vec<Def>) -> Refs {
+        Refs(self.0.clone().into_iter().filter(|r| !defs.contains(&r.def)).collect())
+    }
+}
+
+fn find_refs_in_mod(
+    ctx: &AssistContext,
+    module: Module,
+    visible_from: Option<Module>,
+) -> Option<Refs> {
+    if let Some(from) = visible_from {
+        if !is_mod_visible_from(ctx, module, from) {
+            return None;
+        }
+    }
+
+    let module_scope = module.scope(ctx.db(), visible_from);
+    let refs = module_scope.into_iter().filter_map(|(n, d)| Ref::from_scope_def(n, d)).collect();
+    Some(Refs(refs))
+}
+
+fn is_mod_visible_from(ctx: &AssistContext, module: Module, from: Module) -> bool {
+    match module.parent(ctx.db()) {
+        Some(parent) => {
+            parent.visibility_of(ctx.db(), &ModuleDef::Module(module)).map_or(true, |vis| {
+                vis.is_visible_from(ctx.db(), from.into()) && is_mod_visible_from(ctx, parent, from)
+            })
+        }
+        None => true,
+    }
+}
+
+// looks for name refs in parent use block's siblings
+//
+// mod bar {
+//     mod qux {
+//         struct Qux;
+//     }
+//
+//     pub use qux::Qux;
+// }
+//
+// ↓ ---------------
+// use foo::*$0;
+// use baz::Baz;
+// ↑ ---------------
+fn find_imported_defs(ctx: &AssistContext, star: SyntaxToken) -> Option<Vec<Def>> {
+    let parent_use_item_syntax =
+        star.ancestors().find_map(|n| if ast::Use::can_cast(n.kind()) { Some(n) } else { None })?;
+
+    Some(
+        [Direction::Prev, Direction::Next]
+            .iter()
+            .map(|dir| {
+                parent_use_item_syntax
+                    .siblings(dir.to_owned())
+                    .filter(|n| ast::Use::can_cast(n.kind()))
+            })
+            .flatten()
+            .filter_map(|n| Some(n.descendants().filter_map(ast::NameRef::cast)))
+            .flatten()
+            .filter_map(|r| match NameRefClass::classify(&ctx.sema, &r)? {
+                NameRefClass::Definition(Definition::ModuleDef(def)) => Some(Def::ModuleDef(def)),
+                NameRefClass::Definition(Definition::Macro(def)) => Some(Def::MacroDef(def)),
+                _ => None,
+            })
+            .collect(),
+    )
+}
+
+fn find_names_to_import(
+    ctx: &AssistContext,
+    refs_in_target: Refs,
+    imported_defs: Vec<Def>,
+) -> Vec<Name> {
+    let used_refs = refs_in_target.used_refs(ctx).filter_out_by_defs(imported_defs);
+    used_refs.0.iter().map(|r| r.visible_name.clone()).collect()
+}
+
+fn replace_ast(
+    rewriter: &mut SyntaxRewriter,
+    parent: Either<ast::UseTree, ast::UseTreeList>,
+    path: ast::Path,
+    names_to_import: Vec<Name>,
+) {
+    let existing_use_trees = match parent.clone() {
+        Either::Left(_) => vec![],
+        Either::Right(u) => u
+            .use_trees()
+            .filter(|n|
+            // filter out star
+            n.star_token().is_none())
+            .collect(),
+    };
+
+    let new_use_trees: Vec<ast::UseTree> = names_to_import
+        .iter()
+        .map(|n| {
+            let path = make::path_unqualified(make::path_segment(make::name_ref(&n.to_string())));
+            make::use_tree(path, None, None, false)
+        })
+        .collect();
+
+    let use_trees = [&existing_use_trees[..], &new_use_trees[..]].concat();
+
+    match use_trees.as_slice() {
+        [name] => {
+            if let Some(end_path) = name.path() {
+                rewriter.replace_ast(
+                    &parent.left_or_else(|tl| tl.parent_use_tree()),
+                    &make::use_tree(make::path_concat(path, end_path), None, None, false),
+                );
+            }
+        }
+        names => match &parent {
+            Either::Left(parent) => rewriter.replace_ast(
+                parent,
+                &make::use_tree(path, Some(make::use_tree_list(names.to_owned())), None, false),
+            ),
+            Either::Right(parent) => {
+                rewriter.replace_ast(parent, &make::use_tree_list(names.to_owned()))
+            }
+        },
+    };
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn expanding_glob_import() {
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub struct Bar;
+    pub struct Baz;
+    pub struct Qux;
+
+    pub fn f() {}
+}
+
+use foo::*$0;
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+}
+",
+            r"
+mod foo {
+    pub struct Bar;
+    pub struct Baz;
+    pub struct Qux;
+
+    pub fn f() {}
+}
+
+use foo::{Baz, Bar, f};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+}
+",
+        )
+    }
+
+    #[test]
+    fn expanding_glob_import_with_existing_explicit_names() {
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub struct Bar;
+    pub struct Baz;
+    pub struct Qux;
+
+    pub fn f() {}
+}
+
+use foo::{*$0, f};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+}
+",
+            r"
+mod foo {
+    pub struct Bar;
+    pub struct Baz;
+    pub struct Qux;
+
+    pub fn f() {}
+}
+
+use foo::{f, Baz, Bar};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+}
+",
+        )
+    }
+
+    #[test]
+    fn expanding_glob_import_with_existing_uses_in_same_module() {
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub struct Bar;
+    pub struct Baz;
+    pub struct Qux;
+
+    pub fn f() {}
+}
+
+use foo::Bar;
+use foo::{*$0, f};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+}
+",
+            r"
+mod foo {
+    pub struct Bar;
+    pub struct Baz;
+    pub struct Qux;
+
+    pub fn f() {}
+}
+
+use foo::Bar;
+use foo::{f, Baz};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+}
+",
+        )
+    }
+
+    #[test]
+    fn expanding_nested_glob_import() {
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+    }
+}
+
+use foo::{bar::{*$0, f}, baz::*};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+}
+",
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+    }
+}
+
+use foo::{bar::{f, Baz, Bar}, baz::*};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+}
+",
+        );
+
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+    }
+}
+
+use foo::{bar::{Bar, Baz, f}, baz::*$0};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+}
+",
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+    }
+}
+
+use foo::{bar::{Bar, Baz, f}, baz::g};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+}
+",
+        );
+
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+
+        pub mod qux {
+            pub fn h() {}
+            pub fn m() {}
+
+            pub mod q {
+                pub fn j() {}
+            }
+        }
+    }
+}
+
+use foo::{
+    bar::{*, f},
+    baz::{g, qux::*$0}
+};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+    h();
+    q::j();
+}
+",
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+
+        pub mod qux {
+            pub fn h() {}
+            pub fn m() {}
+
+            pub mod q {
+                pub fn j() {}
+            }
+        }
+    }
+}
+
+use foo::{
+    bar::{*, f},
+    baz::{g, qux::{q, h}}
+};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+    h();
+    q::j();
+}
+",
+        );
+
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+
+        pub mod qux {
+            pub fn h() {}
+            pub fn m() {}
+
+            pub mod q {
+                pub fn j() {}
+            }
+        }
+    }
+}
+
+use foo::{
+    bar::{*, f},
+    baz::{g, qux::{h, q::*$0}}
+};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+    h();
+    j();
+}
+",
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+
+        pub mod qux {
+            pub fn h() {}
+            pub fn m() {}
+
+            pub mod q {
+                pub fn j() {}
+            }
+        }
+    }
+}
+
+use foo::{
+    bar::{*, f},
+    baz::{g, qux::{h, q::j}}
+};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+    h();
+    j();
+}
+",
+        );
+
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+
+        pub mod qux {
+            pub fn h() {}
+            pub fn m() {}
+
+            pub mod q {
+                pub fn j() {}
+            }
+        }
+    }
+}
+
+use foo::{
+    bar::{*, f},
+    baz::{g, qux::{q::j, *$0}}
+};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+    h();
+    j();
+}
+",
+            r"
+mod foo {
+    pub mod bar {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+
+        pub fn f() {}
+    }
+
+    pub mod baz {
+        pub fn g() {}
+
+        pub mod qux {
+            pub fn h() {}
+            pub fn m() {}
+
+            pub mod q {
+                pub fn j() {}
+            }
+        }
+    }
+}
+
+use foo::{
+    bar::{*, f},
+    baz::{g, qux::{q::j, h}}
+};
+
+fn qux(bar: Bar, baz: Baz) {
+    f();
+    g();
+    h();
+    j();
+}
+",
+        );
+    }
+
+    #[test]
+    fn expanding_glob_import_with_macro_defs() {
+        // FIXME: this is currently fails because `Definition::find_usages` ignores macros
+        //       https://github.com/rust-analyzer/rust-analyzer/issues/3484
+        //
+        //         check_assist(
+        //             expand_glob_import,
+        //             r"
+        // //- /lib.rs crate:foo
+        // #[macro_export]
+        // macro_rules! bar {
+        //     () => ()
+        // }
+
+        // pub fn baz() {}
+
+        // //- /main.rs crate:main deps:foo
+        // use foo::*$0;
+
+        // fn main() {
+        //     bar!();
+        //     baz();
+        // }
+        // ",
+        //             r"
+        // use foo::{bar, baz};
+
+        // fn main() {
+        //     bar!();
+        //     baz();
+        // }
+        // ",
+        //         )
+    }
+
+    #[test]
+    fn expanding_glob_import_with_trait_method_uses() {
+        check_assist(
+            expand_glob_import,
+            r"
+//- /lib.rs crate:foo
+pub trait Tr {
+    fn method(&self) {}
+}
+impl Tr for () {}
+
+//- /main.rs crate:main deps:foo
+use foo::*$0;
+
+fn main() {
+    ().method();
+}
+",
+            r"
+use foo::Tr;
+
+fn main() {
+    ().method();
+}
+",
+        );
+
+        check_assist(
+            expand_glob_import,
+            r"
+//- /lib.rs crate:foo
+pub trait Tr {
+    fn method(&self) {}
+}
+impl Tr for () {}
+
+pub trait Tr2 {
+    fn method2(&self) {}
+}
+impl Tr2 for () {}
+
+//- /main.rs crate:main deps:foo
+use foo::*$0;
+
+fn main() {
+    ().method();
+}
+",
+            r"
+use foo::Tr;
+
+fn main() {
+    ().method();
+}
+",
+        );
+    }
+
+    #[test]
+    fn expanding_is_not_applicable_if_target_module_is_not_accessible_from_current_scope() {
+        check_assist_not_applicable(
+            expand_glob_import,
+            r"
+mod foo {
+    mod bar {
+        pub struct Bar;
+    }
+}
+
+use foo::bar::*$0;
+
+fn baz(bar: Bar) {}
+",
+        );
+
+        check_assist_not_applicable(
+            expand_glob_import,
+            r"
+mod foo {
+    mod bar {
+        pub mod baz {
+            pub struct Baz;
+        }
+    }
+}
+
+use foo::bar::baz::*$0;
+
+fn qux(baz: Baz) {}
+",
+        );
+    }
+
+    #[test]
+    fn expanding_is_not_applicable_if_cursor_is_not_in_star_token() {
+        check_assist_not_applicable(
+            expand_glob_import,
+            r"
+    mod foo {
+        pub struct Bar;
+        pub struct Baz;
+        pub struct Qux;
+    }
+
+    use foo::Bar$0;
+
+    fn qux(bar: Bar, baz: Baz) {}
+    ",
+        )
+    }
+
+    #[test]
+    fn expanding_glob_import_single_nested_glob_only() {
+        check_assist(
+            expand_glob_import,
+            r"
+mod foo {
+    pub struct Bar;
+}
+
+use foo::{*$0};
+
+struct Baz {
+    bar: Bar
+}
+",
+            r"
+mod foo {
+    pub struct Bar;
+}
+
+use foo::Bar;
+
+struct Baz {
+    bar: Bar
+}
+",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/extract_function.rs b/crates/ide_assists/src/handlers/extract_function.rs
new file mode 100644
index 000000000..9f34cc725
--- /dev/null
+++ b/crates/ide_assists/src/handlers/extract_function.rs
@@ -0,0 +1,3378 @@
+use std::iter;
+
+use ast::make;
+use either::Either;
+use hir::{HirDisplay, Local};
+use ide_db::{
+    defs::{Definition, NameRefClass},
+    search::{FileReference, ReferenceAccess, SearchScope},
+};
+use itertools::Itertools;
+use stdx::format_to;
+use syntax::{
+    algo::SyntaxRewriter,
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+        AstNode,
+    },
+    SyntaxElement,
+    SyntaxKind::{self, BLOCK_EXPR, BREAK_EXPR, COMMENT, PATH_EXPR, RETURN_EXPR},
+    SyntaxNode, SyntaxToken, TextRange, TextSize, TokenAtOffset, WalkEvent, T,
+};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId,
+};
+
+// Assist: extract_function
+//
+// Extracts selected statements into new function.
+//
+// ```
+// fn main() {
+//     let n = 1;
+//     $0let m = n + 2;
+//     let k = m + n;$0
+//     let g = 3;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     let n = 1;
+//     fun_name(n);
+//     let g = 3;
+// }
+//
+// fn $0fun_name(n: i32) {
+//     let m = n + 2;
+//     let k = m + n;
+// }
+// ```
+pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    if ctx.frange.range.is_empty() {
+        return None;
+    }
+
+    let node = ctx.covering_element();
+    if node.kind() == COMMENT {
+        mark::hit!(extract_function_in_comment_is_not_applicable);
+        return None;
+    }
+
+    let node = element_to_node(node);
+
+    let body = extraction_target(&node, ctx.frange.range)?;
+
+    let vars_used_in_body = vars_used_in_body(ctx, &body);
+    let self_param = self_param_from_usages(ctx, &body, &vars_used_in_body);
+
+    let anchor = if self_param.is_some() { Anchor::Method } else { Anchor::Freestanding };
+    let insert_after = scope_for_fn_insertion(&body, anchor)?;
+    let module = ctx.sema.scope(&insert_after).module()?;
+
+    let vars_defined_in_body_and_outlive = vars_defined_in_body_and_outlive(ctx, &body);
+    let ret_ty = body_return_ty(ctx, &body)?;
+
+    // FIXME: we compute variables that outlive here just to check `never!` condition
+    //        this requires traversing whole `body` (cheap) and finding all references (expensive)
+    //        maybe we can move this check to `edit` closure somehow?
+    if stdx::never!(!vars_defined_in_body_and_outlive.is_empty() && !ret_ty.is_unit()) {
+        // We should not have variables that outlive body if we have expression block
+        return None;
+    }
+    let control_flow = external_control_flow(ctx, &body)?;
+
+    let target_range = body.text_range();
+
+    acc.add(
+        AssistId("extract_function", crate::AssistKind::RefactorExtract),
+        "Extract into function",
+        target_range,
+        move |builder| {
+            let params = extracted_function_params(ctx, &body, &vars_used_in_body);
+
+            let fun = Function {
+                name: "fun_name".to_string(),
+                self_param: self_param.map(|(_, pat)| pat),
+                params,
+                control_flow,
+                ret_ty,
+                body,
+                vars_defined_in_body_and_outlive,
+            };
+
+            let new_indent = IndentLevel::from_node(&insert_after);
+            let old_indent = fun.body.indent_level();
+
+            builder.replace(target_range, format_replacement(ctx, &fun, old_indent));
+
+            let fn_def = format_function(ctx, module, &fun, old_indent, new_indent);
+            let insert_offset = insert_after.text_range().end();
+            builder.insert(insert_offset, fn_def);
+        },
+    )
+}
+
+fn external_control_flow(ctx: &AssistContext, body: &FunctionBody) -> Option<ControlFlow> {
+    let mut ret_expr = None;
+    let mut try_expr = None;
+    let mut break_expr = None;
+    let mut continue_expr = None;
+    let (syntax, text_range) = match body {
+        FunctionBody::Expr(expr) => (expr.syntax(), expr.syntax().text_range()),
+        FunctionBody::Span { parent, text_range } => (parent.syntax(), *text_range),
+    };
+
+    let mut nested_loop = None;
+    let mut nested_scope = None;
+
+    for e in syntax.preorder() {
+        let e = match e {
+            WalkEvent::Enter(e) => e,
+            WalkEvent::Leave(e) => {
+                if nested_loop.as_ref() == Some(&e) {
+                    nested_loop = None;
+                }
+                if nested_scope.as_ref() == Some(&e) {
+                    nested_scope = None;
+                }
+                continue;
+            }
+        };
+        if nested_scope.is_some() {
+            continue;
+        }
+        if !text_range.contains_range(e.text_range()) {
+            continue;
+        }
+        match e.kind() {
+            SyntaxKind::LOOP_EXPR | SyntaxKind::WHILE_EXPR | SyntaxKind::FOR_EXPR => {
+                if nested_loop.is_none() {
+                    nested_loop = Some(e);
+                }
+            }
+            SyntaxKind::FN
+            | SyntaxKind::CONST
+            | SyntaxKind::STATIC
+            | SyntaxKind::IMPL
+            | SyntaxKind::MODULE => {
+                if nested_scope.is_none() {
+                    nested_scope = Some(e);
+                }
+            }
+            SyntaxKind::RETURN_EXPR => {
+                ret_expr = Some(ast::ReturnExpr::cast(e).unwrap());
+            }
+            SyntaxKind::TRY_EXPR => {
+                try_expr = Some(ast::TryExpr::cast(e).unwrap());
+            }
+            SyntaxKind::BREAK_EXPR if nested_loop.is_none() => {
+                break_expr = Some(ast::BreakExpr::cast(e).unwrap());
+            }
+            SyntaxKind::CONTINUE_EXPR if nested_loop.is_none() => {
+                continue_expr = Some(ast::ContinueExpr::cast(e).unwrap());
+            }
+            _ => {}
+        }
+    }
+
+    let kind = match (try_expr, ret_expr, break_expr, continue_expr) {
+        (Some(e), None, None, None) => {
+            let func = e.syntax().ancestors().find_map(ast::Fn::cast)?;
+            let def = ctx.sema.to_def(&func)?;
+            let ret_ty = def.ret_type(ctx.db());
+            let kind = try_kind_of_ty(ret_ty, ctx)?;
+
+            Some(FlowKind::Try { kind })
+        }
+        (Some(_), Some(r), None, None) => match r.expr() {
+            Some(expr) => {
+                if let Some(kind) = expr_err_kind(&expr, ctx) {
+                    Some(FlowKind::TryReturn { expr, kind })
+                } else {
+                    mark::hit!(external_control_flow_try_and_return_non_err);
+                    return None;
+                }
+            }
+            None => return None,
+        },
+        (Some(_), _, _, _) => {
+            mark::hit!(external_control_flow_try_and_bc);
+            return None;
+        }
+        (None, Some(r), None, None) => match r.expr() {
+            Some(expr) => Some(FlowKind::ReturnValue(expr)),
+            None => Some(FlowKind::Return),
+        },
+        (None, Some(_), _, _) => {
+            mark::hit!(external_control_flow_return_and_bc);
+            return None;
+        }
+        (None, None, Some(_), Some(_)) => {
+            mark::hit!(external_control_flow_break_and_continue);
+            return None;
+        }
+        (None, None, Some(b), None) => match b.expr() {
+            Some(expr) => Some(FlowKind::BreakValue(expr)),
+            None => Some(FlowKind::Break),
+        },
+        (None, None, None, Some(_)) => Some(FlowKind::Continue),
+        (None, None, None, None) => None,
+    };
+
+    Some(ControlFlow { kind })
+}
+
+/// Checks is expr is `Err(_)` or `None`
+fn expr_err_kind(expr: &ast::Expr, ctx: &AssistContext) -> Option<TryKind> {
+    let func_name = match expr {
+        ast::Expr::CallExpr(call_expr) => call_expr.expr()?,
+        ast::Expr::PathExpr(_) => expr.clone(),
+        _ => return None,
+    };
+    let text = func_name.syntax().text();
+
+    if text == "Err" {
+        Some(TryKind::Result { ty: ctx.sema.type_of_expr(expr)? })
+    } else if text == "None" {
+        Some(TryKind::Option)
+    } else {
+        None
+    }
+}
+
+#[derive(Debug)]
+struct Function {
+    name: String,
+    self_param: Option<ast::SelfParam>,
+    params: Vec<Param>,
+    control_flow: ControlFlow,
+    ret_ty: RetType,
+    body: FunctionBody,
+    vars_defined_in_body_and_outlive: Vec<Local>,
+}
+
+#[derive(Debug)]
+struct Param {
+    var: Local,
+    ty: hir::Type,
+    has_usages_afterwards: bool,
+    has_mut_inside_body: bool,
+    is_copy: bool,
+}
+
+#[derive(Debug)]
+struct ControlFlow {
+    kind: Option<FlowKind>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum ParamKind {
+    Value,
+    MutValue,
+    SharedRef,
+    MutRef,
+}
+
+#[derive(Debug, Eq, PartialEq)]
+enum FunType {
+    Unit,
+    Single(hir::Type),
+    Tuple(Vec<hir::Type>),
+}
+
+impl Function {
+    fn return_type(&self, ctx: &AssistContext) -> FunType {
+        match &self.ret_ty {
+            RetType::Expr(ty) if ty.is_unit() => FunType::Unit,
+            RetType::Expr(ty) => FunType::Single(ty.clone()),
+            RetType::Stmt => match self.vars_defined_in_body_and_outlive.as_slice() {
+                [] => FunType::Unit,
+                [var] => FunType::Single(var.ty(ctx.db())),
+                vars => {
+                    let types = vars.iter().map(|v| v.ty(ctx.db())).collect();
+                    FunType::Tuple(types)
+                }
+            },
+        }
+    }
+}
+
+impl ParamKind {
+    fn is_ref(&self) -> bool {
+        matches!(self, ParamKind::SharedRef | ParamKind::MutRef)
+    }
+}
+
+impl Param {
+    fn kind(&self) -> ParamKind {
+        match (self.has_usages_afterwards, self.has_mut_inside_body, self.is_copy) {
+            (true, true, _) => ParamKind::MutRef,
+            (true, false, false) => ParamKind::SharedRef,
+            (false, true, _) => ParamKind::MutValue,
+            (true, false, true) | (false, false, _) => ParamKind::Value,
+        }
+    }
+
+    fn to_arg(&self, ctx: &AssistContext) -> ast::Expr {
+        let var = path_expr_from_local(ctx, self.var);
+        match self.kind() {
+            ParamKind::Value | ParamKind::MutValue => var,
+            ParamKind::SharedRef => make::expr_ref(var, false),
+            ParamKind::MutRef => make::expr_ref(var, true),
+        }
+    }
+
+    fn to_param(&self, ctx: &AssistContext, module: hir::Module) -> ast::Param {
+        let var = self.var.name(ctx.db()).unwrap().to_string();
+        let var_name = make::name(&var);
+        let pat = match self.kind() {
+            ParamKind::MutValue => make::ident_mut_pat(var_name),
+            ParamKind::Value | ParamKind::SharedRef | ParamKind::MutRef => {
+                make::ident_pat(var_name)
+            }
+        };
+
+        let ty = make_ty(&self.ty, ctx, module);
+        let ty = match self.kind() {
+            ParamKind::Value | ParamKind::MutValue => ty,
+            ParamKind::SharedRef => make::ty_ref(ty, false),
+            ParamKind::MutRef => make::ty_ref(ty, true),
+        };
+
+        make::param(pat.into(), ty)
+    }
+}
+
+/// Control flow that is exported from extracted function
+///
+/// E.g.:
+/// ```rust,no_run
+/// loop {
+///     $0
+///     if 42 == 42 {
+///         break;
+///     }
+///     $0
+/// }
+/// ```
+#[derive(Debug, Clone)]
+enum FlowKind {
+    /// Return without value (`return;`)
+    Return,
+    /// Return with value (`return $expr;`)
+    ReturnValue(ast::Expr),
+    Try {
+        kind: TryKind,
+    },
+    TryReturn {
+        expr: ast::Expr,
+        kind: TryKind,
+    },
+    /// Break without value (`return;`)
+    Break,
+    /// Break with value (`break $expr;`)
+    BreakValue(ast::Expr),
+    /// Continue
+    Continue,
+}
+
+#[derive(Debug, Clone)]
+enum TryKind {
+    Option,
+    Result { ty: hir::Type },
+}
+
+impl FlowKind {
+    fn make_result_handler(&self, expr: Option<ast::Expr>) -> ast::Expr {
+        match self {
+            FlowKind::Return | FlowKind::ReturnValue(_) => make::expr_return(expr),
+            FlowKind::Break | FlowKind::BreakValue(_) => make::expr_break(expr),
+            FlowKind::Try { .. } | FlowKind::TryReturn { .. } => {
+                stdx::never!("cannot have result handler with try");
+                expr.unwrap_or_else(|| make::expr_return(None))
+            }
+            FlowKind::Continue => {
+                stdx::always!(expr.is_none(), "continue with value is not possible");
+                make::expr_continue()
+            }
+        }
+    }
+
+    fn expr_ty(&self, ctx: &AssistContext) -> Option<hir::Type> {
+        match self {
+            FlowKind::ReturnValue(expr)
+            | FlowKind::BreakValue(expr)
+            | FlowKind::TryReturn { expr, .. } => ctx.sema.type_of_expr(expr),
+            FlowKind::Try { .. } => {
+                stdx::never!("try does not have defined expr_ty");
+                None
+            }
+            FlowKind::Return | FlowKind::Break | FlowKind::Continue => None,
+        }
+    }
+}
+
+fn try_kind_of_ty(ty: hir::Type, ctx: &AssistContext) -> Option<TryKind> {
+    if ty.is_unknown() {
+        // We favour Result for `expr?`
+        return Some(TryKind::Result { ty });
+    }
+    let adt = ty.as_adt()?;
+    let name = adt.name(ctx.db());
+    // FIXME: use lang items to determine if it is std type or user defined
+    //        E.g. if user happens to define type named `Option`, we would have false positive
+    match name.to_string().as_str() {
+        "Option" => Some(TryKind::Option),
+        "Result" => Some(TryKind::Result { ty }),
+        _ => None,
+    }
+}
+
+#[derive(Debug)]
+enum RetType {
+    Expr(hir::Type),
+    Stmt,
+}
+
+impl RetType {
+    fn is_unit(&self) -> bool {
+        match self {
+            RetType::Expr(ty) => ty.is_unit(),
+            RetType::Stmt => true,
+        }
+    }
+}
+
+/// Semantically same as `ast::Expr`, but preserves identity when using only part of the Block
+#[derive(Debug)]
+enum FunctionBody {
+    Expr(ast::Expr),
+    Span { parent: ast::BlockExpr, text_range: TextRange },
+}
+
+impl FunctionBody {
+    fn from_whole_node(node: SyntaxNode) -> Option<Self> {
+        match node.kind() {
+            PATH_EXPR => None,
+            BREAK_EXPR => ast::BreakExpr::cast(node).and_then(|e| e.expr()).map(Self::Expr),
+            RETURN_EXPR => ast::ReturnExpr::cast(node).and_then(|e| e.expr()).map(Self::Expr),
+            BLOCK_EXPR => ast::BlockExpr::cast(node)
+                .filter(|it| it.is_standalone())
+                .map(Into::into)
+                .map(Self::Expr),
+            _ => ast::Expr::cast(node).map(Self::Expr),
+        }
+    }
+
+    fn from_range(node: SyntaxNode, text_range: TextRange) -> Option<FunctionBody> {
+        let block = ast::BlockExpr::cast(node)?;
+        Some(Self::Span { parent: block, text_range })
+    }
+
+    fn indent_level(&self) -> IndentLevel {
+        match &self {
+            FunctionBody::Expr(expr) => IndentLevel::from_node(expr.syntax()),
+            FunctionBody::Span { parent, .. } => IndentLevel::from_node(parent.syntax()) + 1,
+        }
+    }
+
+    fn tail_expr(&self) -> Option<ast::Expr> {
+        match &self {
+            FunctionBody::Expr(expr) => Some(expr.clone()),
+            FunctionBody::Span { parent, text_range } => {
+                let tail_expr = parent.tail_expr()?;
+                if text_range.contains_range(tail_expr.syntax().text_range()) {
+                    Some(tail_expr)
+                } else {
+                    None
+                }
+            }
+        }
+    }
+
+    fn descendants(&self) -> impl Iterator<Item = SyntaxNode> + '_ {
+        match self {
+            FunctionBody::Expr(expr) => Either::Right(expr.syntax().descendants()),
+            FunctionBody::Span { parent, text_range } => Either::Left(
+                parent
+                    .syntax()
+                    .descendants()
+                    .filter(move |it| text_range.contains_range(it.text_range())),
+            ),
+        }
+    }
+
+    fn text_range(&self) -> TextRange {
+        match self {
+            FunctionBody::Expr(expr) => expr.syntax().text_range(),
+            FunctionBody::Span { parent: _, text_range } => *text_range,
+        }
+    }
+
+    fn contains_range(&self, range: TextRange) -> bool {
+        self.text_range().contains_range(range)
+    }
+
+    fn preceedes_range(&self, range: TextRange) -> bool {
+        self.text_range().end() <= range.start()
+    }
+
+    fn contains_node(&self, node: &SyntaxNode) -> bool {
+        self.contains_range(node.text_range())
+    }
+}
+
+impl HasTokenAtOffset for FunctionBody {
+    fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken> {
+        match self {
+            FunctionBody::Expr(expr) => expr.syntax().token_at_offset(offset),
+            FunctionBody::Span { parent, text_range } => {
+                match parent.syntax().token_at_offset(offset) {
+                    TokenAtOffset::None => TokenAtOffset::None,
+                    TokenAtOffset::Single(t) => {
+                        if text_range.contains_range(t.text_range()) {
+                            TokenAtOffset::Single(t)
+                        } else {
+                            TokenAtOffset::None
+                        }
+                    }
+                    TokenAtOffset::Between(a, b) => {
+                        match (
+                            text_range.contains_range(a.text_range()),
+                            text_range.contains_range(b.text_range()),
+                        ) {
+                            (true, true) => TokenAtOffset::Between(a, b),
+                            (true, false) => TokenAtOffset::Single(a),
+                            (false, true) => TokenAtOffset::Single(b),
+                            (false, false) => TokenAtOffset::None,
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+/// node or token's parent
+fn element_to_node(node: SyntaxElement) -> SyntaxNode {
+    match node {
+        syntax::NodeOrToken::Node(n) => n,
+        syntax::NodeOrToken::Token(t) => t.parent(),
+    }
+}
+
+/// Try to guess what user wants to extract
+///
+/// We have basically have two cases:
+/// * We want whole node, like `loop {}`, `2 + 2`, `{ let n = 1; }` exprs.
+///   Then we can use `ast::Expr`
+/// * We want a few statements for a block. E.g.
+///   ```rust,no_run
+///   fn foo() -> i32 {
+///     let m = 1;
+///     $0
+///     let n = 2;
+///     let k = 3;
+///     k + n
+///     $0
+///   }
+///   ```
+///
+fn extraction_target(node: &SyntaxNode, selection_range: TextRange) -> Option<FunctionBody> {
+    // we have selected exactly the expr node
+    // wrap it before anything else
+    if node.text_range() == selection_range {
+        let body = FunctionBody::from_whole_node(node.clone());
+        if body.is_some() {
+            return body;
+        }
+    }
+
+    // we have selected a few statements in a block
+    // so covering_element returns the whole block
+    if node.kind() == BLOCK_EXPR {
+        let body = FunctionBody::from_range(node.clone(), selection_range);
+        if body.is_some() {
+            return body;
+        }
+    }
+
+    // we have selected single statement
+    // `from_whole_node` failed because (let) statement is not and expression
+    // so we try to expand covering_element to parent and repeat the previous
+    if let Some(parent) = node.parent() {
+        if parent.kind() == BLOCK_EXPR {
+            let body = FunctionBody::from_range(parent, selection_range);
+            if body.is_some() {
+                return body;
+            }
+        }
+    }
+
+    // select the closest containing expr (both ifs are used)
+    std::iter::once(node.clone()).chain(node.ancestors()).find_map(FunctionBody::from_whole_node)
+}
+
+/// list local variables that are referenced in `body`
+fn vars_used_in_body(ctx: &AssistContext, body: &FunctionBody) -> Vec<Local> {
+    // FIXME: currently usages inside macros are not found
+    body.descendants()
+        .filter_map(ast::NameRef::cast)
+        .filter_map(|name_ref| NameRefClass::classify(&ctx.sema, &name_ref))
+        .map(|name_kind| name_kind.referenced(ctx.db()))
+        .filter_map(|definition| match definition {
+            Definition::Local(local) => Some(local),
+            _ => None,
+        })
+        .unique()
+        .collect()
+}
+
+/// find `self` param, that was not defined inside `body`
+///
+/// It should skip `self` params from impls inside `body`
+fn self_param_from_usages(
+    ctx: &AssistContext,
+    body: &FunctionBody,
+    vars_used_in_body: &[Local],
+) -> Option<(Local, ast::SelfParam)> {
+    let mut iter = vars_used_in_body
+        .iter()
+        .filter(|var| var.is_self(ctx.db()))
+        .map(|var| (var, var.source(ctx.db())))
+        .filter(|(_, src)| is_defined_before(ctx, body, src))
+        .filter_map(|(&node, src)| match src.value {
+            Either::Right(it) => Some((node, it)),
+            Either::Left(_) => {
+                stdx::never!(false, "Local::is_self returned true, but source is IdentPat");
+                None
+            }
+        });
+
+    let self_param = iter.next();
+    stdx::always!(
+        iter.next().is_none(),
+        "body references two different self params, both defined outside"
+    );
+
+    self_param
+}
+
+/// find variables that should be extracted as params
+///
+/// Computes additional info that affects param type and mutability
+fn extracted_function_params(
+    ctx: &AssistContext,
+    body: &FunctionBody,
+    vars_used_in_body: &[Local],
+) -> Vec<Param> {
+    vars_used_in_body
+        .iter()
+        .filter(|var| !var.is_self(ctx.db()))
+        .map(|node| (node, node.source(ctx.db())))
+        .filter(|(_, src)| is_defined_before(ctx, body, src))
+        .filter_map(|(&node, src)| {
+            if src.value.is_left() {
+                Some(node)
+            } else {
+                stdx::never!(false, "Local::is_self returned false, but source is SelfParam");
+                None
+            }
+        })
+        .map(|var| {
+            let usages = LocalUsages::find(ctx, var);
+            let ty = var.ty(ctx.db());
+            let is_copy = ty.is_copy(ctx.db());
+            Param {
+                var,
+                ty,
+                has_usages_afterwards: has_usages_after_body(&usages, body),
+                has_mut_inside_body: has_exclusive_usages(ctx, &usages, body),
+                is_copy,
+            }
+        })
+        .collect()
+}
+
+fn has_usages_after_body(usages: &LocalUsages, body: &FunctionBody) -> bool {
+    usages.iter().any(|reference| body.preceedes_range(reference.range))
+}
+
+/// checks if relevant var is used with `&mut` access inside body
+fn has_exclusive_usages(ctx: &AssistContext, usages: &LocalUsages, body: &FunctionBody) -> bool {
+    usages
+        .iter()
+        .filter(|reference| body.contains_range(reference.range))
+        .any(|reference| reference_is_exclusive(reference, body, ctx))
+}
+
+/// checks if this reference requires `&mut` access inside body
+fn reference_is_exclusive(
+    reference: &FileReference,
+    body: &FunctionBody,
+    ctx: &AssistContext,
+) -> bool {
+    // we directly modify variable with set: `n = 0`, `n += 1`
+    if reference.access == Some(ReferenceAccess::Write) {
+        return true;
+    }
+
+    // we take `&mut` reference to variable: `&mut v`
+    let path = match path_element_of_reference(body, reference) {
+        Some(path) => path,
+        None => return false,
+    };
+
+    expr_require_exclusive_access(ctx, &path).unwrap_or(false)
+}
+
+/// checks if this expr requires `&mut` access, recurses on field access
+fn expr_require_exclusive_access(ctx: &AssistContext, expr: &ast::Expr) -> Option<bool> {
+    let parent = expr.syntax().parent()?;
+
+    if let Some(bin_expr) = ast::BinExpr::cast(parent.clone()) {
+        if bin_expr.op_kind()?.is_assignment() {
+            return Some(bin_expr.lhs()?.syntax() == expr.syntax());
+        }
+        return Some(false);
+    }
+
+    if let Some(ref_expr) = ast::RefExpr::cast(parent.clone()) {
+        return Some(ref_expr.mut_token().is_some());
+    }
+
+    if let Some(method_call) = ast::MethodCallExpr::cast(parent.clone()) {
+        let func = ctx.sema.resolve_method_call(&method_call)?;
+        let self_param = func.self_param(ctx.db())?;
+        let access = self_param.access(ctx.db());
+
+        return Some(matches!(access, hir::Access::Exclusive));
+    }
+
+    if let Some(field) = ast::FieldExpr::cast(parent) {
+        return expr_require_exclusive_access(ctx, &field.into());
+    }
+
+    Some(false)
+}
+
+/// Container of local varaible usages
+///
+/// Semanticall same as `UsageSearchResult`, but provides more convenient interface
+struct LocalUsages(ide_db::search::UsageSearchResult);
+
+impl LocalUsages {
+    fn find(ctx: &AssistContext, var: Local) -> Self {
+        Self(
+            Definition::Local(var)
+                .usages(&ctx.sema)
+                .in_scope(SearchScope::single_file(ctx.frange.file_id))
+                .all(),
+        )
+    }
+
+    fn iter(&self) -> impl Iterator<Item = &FileReference> + '_ {
+        self.0.iter().flat_map(|(_, rs)| rs.iter())
+    }
+}
+
+trait HasTokenAtOffset {
+    fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken>;
+}
+
+impl HasTokenAtOffset for SyntaxNode {
+    fn token_at_offset(&self, offset: TextSize) -> TokenAtOffset<SyntaxToken> {
+        SyntaxNode::token_at_offset(&self, offset)
+    }
+}
+
+/// find relevant `ast::PathExpr` for reference
+///
+/// # Preconditions
+///
+/// `node` must cover `reference`, that is `node.text_range().contains_range(reference.range)`
+fn path_element_of_reference(
+    node: &dyn HasTokenAtOffset,
+    reference: &FileReference,
+) -> Option<ast::Expr> {
+    let token = node.token_at_offset(reference.range.start()).right_biased().or_else(|| {
+        stdx::never!(false, "cannot find token at variable usage: {:?}", reference);
+        None
+    })?;
+    let path = token.ancestors().find_map(ast::Expr::cast).or_else(|| {
+        stdx::never!(false, "cannot find path parent of variable usage: {:?}", token);
+        None
+    })?;
+    stdx::always!(matches!(path, ast::Expr::PathExpr(_)));
+    Some(path)
+}
+
+/// list local variables defined inside `body`
+fn vars_defined_in_body(body: &FunctionBody, ctx: &AssistContext) -> Vec<Local> {
+    // FIXME: this doesn't work well with macros
+    //        see https://github.com/rust-analyzer/rust-analyzer/pull/7535#discussion_r570048550
+    body.descendants()
+        .filter_map(ast::IdentPat::cast)
+        .filter_map(|let_stmt| ctx.sema.to_def(&let_stmt))
+        .unique()
+        .collect()
+}
+
+/// list local variables defined inside `body` that should be returned from extracted function
+fn vars_defined_in_body_and_outlive(ctx: &AssistContext, body: &FunctionBody) -> Vec<Local> {
+    let mut vars_defined_in_body = vars_defined_in_body(&body, ctx);
+    vars_defined_in_body.retain(|var| var_outlives_body(ctx, body, var));
+    vars_defined_in_body
+}
+
+/// checks if the relevant local was defined before(outside of) body
+fn is_defined_before(
+    ctx: &AssistContext,
+    body: &FunctionBody,
+    src: &hir::InFile<Either<ast::IdentPat, ast::SelfParam>>,
+) -> bool {
+    src.file_id.original_file(ctx.db()) == ctx.frange.file_id
+        && !body.contains_node(&either_syntax(&src.value))
+}
+
+fn either_syntax(value: &Either<ast::IdentPat, ast::SelfParam>) -> &SyntaxNode {
+    match value {
+        Either::Left(pat) => pat.syntax(),
+        Either::Right(it) => it.syntax(),
+    }
+}
+
+/// checks if local variable is used after(outside of) body
+fn var_outlives_body(ctx: &AssistContext, body: &FunctionBody, var: &Local) -> bool {
+    let usages = LocalUsages::find(ctx, *var);
+    let has_usages = usages.iter().any(|reference| body.preceedes_range(reference.range));
+    has_usages
+}
+
+fn body_return_ty(ctx: &AssistContext, body: &FunctionBody) -> Option<RetType> {
+    match body.tail_expr() {
+        Some(expr) => {
+            let ty = ctx.sema.type_of_expr(&expr)?;
+            Some(RetType::Expr(ty))
+        }
+        None => Some(RetType::Stmt),
+    }
+}
+/// Where to put extracted function definition
+#[derive(Debug)]
+enum Anchor {
+    /// Extract free function and put right after current top-level function
+    Freestanding,
+    /// Extract method and put right after current function in the impl-block
+    Method,
+}
+
+/// find where to put extracted function definition
+///
+/// Function should be put right after returned node
+fn scope_for_fn_insertion(body: &FunctionBody, anchor: Anchor) -> Option<SyntaxNode> {
+    match body {
+        FunctionBody::Expr(e) => scope_for_fn_insertion_node(e.syntax(), anchor),
+        FunctionBody::Span { parent, .. } => scope_for_fn_insertion_node(parent.syntax(), anchor),
+    }
+}
+
+fn scope_for_fn_insertion_node(node: &SyntaxNode, anchor: Anchor) -> Option<SyntaxNode> {
+    let mut ancestors = node.ancestors().peekable();
+    let mut last_ancestor = None;
+    while let Some(next_ancestor) = ancestors.next() {
+        match next_ancestor.kind() {
+            SyntaxKind::SOURCE_FILE => break,
+            SyntaxKind::ITEM_LIST => {
+                if !matches!(anchor, Anchor::Freestanding) {
+                    continue;
+                }
+                if ancestors.peek().map(SyntaxNode::kind) == Some(SyntaxKind::MODULE) {
+                    break;
+                }
+            }
+            SyntaxKind::ASSOC_ITEM_LIST => {
+                if !matches!(anchor, Anchor::Method) {
+                    continue;
+                }
+                if ancestors.peek().map(SyntaxNode::kind) == Some(SyntaxKind::IMPL) {
+                    break;
+                }
+            }
+            _ => {}
+        }
+        last_ancestor = Some(next_ancestor);
+    }
+    last_ancestor
+}
+
+fn format_replacement(ctx: &AssistContext, fun: &Function, indent: IndentLevel) -> String {
+    let ret_ty = fun.return_type(ctx);
+
+    let args = fun.params.iter().map(|param| param.to_arg(ctx));
+    let args = make::arg_list(args);
+    let call_expr = if fun.self_param.is_some() {
+        let self_arg = make::expr_path(make_path_from_text("self"));
+        make::expr_method_call(self_arg, &fun.name, args)
+    } else {
+        let func = make::expr_path(make_path_from_text(&fun.name));
+        make::expr_call(func, args)
+    };
+
+    let handler = FlowHandler::from_ret_ty(fun, &ret_ty);
+
+    let expr = handler.make_call_expr(call_expr).indent(indent);
+
+    let mut buf = String::new();
+    match fun.vars_defined_in_body_and_outlive.as_slice() {
+        [] => {}
+        [var] => format_to!(buf, "let {} = ", var.name(ctx.db()).unwrap()),
+        [v0, vs @ ..] => {
+            buf.push_str("let (");
+            format_to!(buf, "{}", v0.name(ctx.db()).unwrap());
+            for var in vs {
+                format_to!(buf, ", {}", var.name(ctx.db()).unwrap());
+            }
+            buf.push_str(") = ");
+        }
+    }
+    format_to!(buf, "{}", expr);
+    if fun.ret_ty.is_unit()
+        && (!fun.vars_defined_in_body_and_outlive.is_empty() || !expr.is_block_like())
+    {
+        buf.push(';');
+    }
+    buf
+}
+
+enum FlowHandler {
+    None,
+    Try { kind: TryKind },
+    If { action: FlowKind },
+    IfOption { action: FlowKind },
+    MatchOption { none: FlowKind },
+    MatchResult { err: FlowKind },
+}
+
+impl FlowHandler {
+    fn from_ret_ty(fun: &Function, ret_ty: &FunType) -> FlowHandler {
+        match &fun.control_flow.kind {
+            None => FlowHandler::None,
+            Some(flow_kind) => {
+                let action = flow_kind.clone();
+                if *ret_ty == FunType::Unit {
+                    match flow_kind {
+                        FlowKind::Return | FlowKind::Break | FlowKind::Continue => {
+                            FlowHandler::If { action }
+                        }
+                        FlowKind::ReturnValue(_) | FlowKind::BreakValue(_) => {
+                            FlowHandler::IfOption { action }
+                        }
+                        FlowKind::Try { kind } | FlowKind::TryReturn { kind, .. } => {
+                            FlowHandler::Try { kind: kind.clone() }
+                        }
+                    }
+                } else {
+                    match flow_kind {
+                        FlowKind::Return | FlowKind::Break | FlowKind::Continue => {
+                            FlowHandler::MatchOption { none: action }
+                        }
+                        FlowKind::ReturnValue(_) | FlowKind::BreakValue(_) => {
+                            FlowHandler::MatchResult { err: action }
+                        }
+                        FlowKind::Try { kind } | FlowKind::TryReturn { kind, .. } => {
+                            FlowHandler::Try { kind: kind.clone() }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    fn make_call_expr(&self, call_expr: ast::Expr) -> ast::Expr {
+        match self {
+            FlowHandler::None => call_expr,
+            FlowHandler::Try { kind: _ } => make::expr_try(call_expr),
+            FlowHandler::If { action } => {
+                let action = action.make_result_handler(None);
+                let stmt = make::expr_stmt(action);
+                let block = make::block_expr(iter::once(stmt.into()), None);
+                let condition = make::condition(call_expr, None);
+                make::expr_if(condition, block, None)
+            }
+            FlowHandler::IfOption { action } => {
+                let path = make_path_from_text("Some");
+                let value_pat = make::ident_pat(make::name("value"));
+                let pattern = make::tuple_struct_pat(path, iter::once(value_pat.into()));
+                let cond = make::condition(call_expr, Some(pattern.into()));
+                let value = make::expr_path(make_path_from_text("value"));
+                let action_expr = action.make_result_handler(Some(value));
+                let action_stmt = make::expr_stmt(action_expr);
+                let then = make::block_expr(iter::once(action_stmt.into()), None);
+                make::expr_if(cond, then, None)
+            }
+            FlowHandler::MatchOption { none } => {
+                let some_name = "value";
+
+                let some_arm = {
+                    let path = make_path_from_text("Some");
+                    let value_pat = make::ident_pat(make::name(some_name));
+                    let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
+                    let value = make::expr_path(make_path_from_text(some_name));
+                    make::match_arm(iter::once(pat.into()), value)
+                };
+                let none_arm = {
+                    let path = make_path_from_text("None");
+                    let pat = make::path_pat(path);
+                    make::match_arm(iter::once(pat), none.make_result_handler(None))
+                };
+                let arms = make::match_arm_list(vec![some_arm, none_arm]);
+                make::expr_match(call_expr, arms)
+            }
+            FlowHandler::MatchResult { err } => {
+                let ok_name = "value";
+                let err_name = "value";
+
+                let ok_arm = {
+                    let path = make_path_from_text("Ok");
+                    let value_pat = make::ident_pat(make::name(ok_name));
+                    let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
+                    let value = make::expr_path(make_path_from_text(ok_name));
+                    make::match_arm(iter::once(pat.into()), value)
+                };
+                let err_arm = {
+                    let path = make_path_from_text("Err");
+                    let value_pat = make::ident_pat(make::name(err_name));
+                    let pat = make::tuple_struct_pat(path, iter::once(value_pat.into()));
+                    let value = make::expr_path(make_path_from_text(err_name));
+                    make::match_arm(iter::once(pat.into()), err.make_result_handler(Some(value)))
+                };
+                let arms = make::match_arm_list(vec![ok_arm, err_arm]);
+                make::expr_match(call_expr, arms)
+            }
+        }
+    }
+}
+
+fn make_path_from_text(text: &str) -> ast::Path {
+    make::path_unqualified(make::path_segment(make::name_ref(text)))
+}
+
+fn path_expr_from_local(ctx: &AssistContext, var: Local) -> ast::Expr {
+    let name = var.name(ctx.db()).unwrap().to_string();
+    make::expr_path(make_path_from_text(&name))
+}
+
+fn format_function(
+    ctx: &AssistContext,
+    module: hir::Module,
+    fun: &Function,
+    old_indent: IndentLevel,
+    new_indent: IndentLevel,
+) -> String {
+    let mut fn_def = String::new();
+    let params = make_param_list(ctx, module, fun);
+    let ret_ty = make_ret_ty(ctx, module, fun);
+    let body = make_body(ctx, old_indent, new_indent, fun);
+    format_to!(fn_def, "\n\n{}fn $0{}{}", new_indent, fun.name, params);
+    if let Some(ret_ty) = ret_ty {
+        format_to!(fn_def, " {}", ret_ty);
+    }
+    format_to!(fn_def, " {}", body);
+
+    fn_def
+}
+
+fn make_param_list(ctx: &AssistContext, module: hir::Module, fun: &Function) -> ast::ParamList {
+    let self_param = fun.self_param.clone();
+    let params = fun.params.iter().map(|param| param.to_param(ctx, module));
+    make::param_list(self_param, params)
+}
+
+impl FunType {
+    fn make_ty(&self, ctx: &AssistContext, module: hir::Module) -> ast::Type {
+        match self {
+            FunType::Unit => make::ty_unit(),
+            FunType::Single(ty) => make_ty(ty, ctx, module),
+            FunType::Tuple(types) => match types.as_slice() {
+                [] => {
+                    stdx::never!("tuple type with 0 elements");
+                    make::ty_unit()
+                }
+                [ty] => {
+                    stdx::never!("tuple type with 1 element");
+                    make_ty(ty, ctx, module)
+                }
+                types => {
+                    let types = types.iter().map(|ty| make_ty(ty, ctx, module));
+                    make::ty_tuple(types)
+                }
+            },
+        }
+    }
+}
+
+fn make_ret_ty(ctx: &AssistContext, module: hir::Module, fun: &Function) -> Option<ast::RetType> {
+    let fun_ty = fun.return_type(ctx);
+    let handler = FlowHandler::from_ret_ty(fun, &fun_ty);
+    let ret_ty = match &handler {
+        FlowHandler::None => {
+            if matches!(fun_ty, FunType::Unit) {
+                return None;
+            }
+            fun_ty.make_ty(ctx, module)
+        }
+        FlowHandler::Try { kind: TryKind::Option } => {
+            make::ty_generic(make::name_ref("Option"), iter::once(fun_ty.make_ty(ctx, module)))
+        }
+        FlowHandler::Try { kind: TryKind::Result { ty: parent_ret_ty } } => {
+            let handler_ty = parent_ret_ty
+                .type_parameters()
+                .nth(1)
+                .map(|ty| make_ty(&ty, ctx, module))
+                .unwrap_or_else(make::ty_unit);
+            make::ty_generic(
+                make::name_ref("Result"),
+                vec![fun_ty.make_ty(ctx, module), handler_ty],
+            )
+        }
+        FlowHandler::If { .. } => make::ty("bool"),
+        FlowHandler::IfOption { action } => {
+            let handler_ty = action
+                .expr_ty(ctx)
+                .map(|ty| make_ty(&ty, ctx, module))
+                .unwrap_or_else(make::ty_unit);
+            make::ty_generic(make::name_ref("Option"), iter::once(handler_ty))
+        }
+        FlowHandler::MatchOption { .. } => {
+            make::ty_generic(make::name_ref("Option"), iter::once(fun_ty.make_ty(ctx, module)))
+        }
+        FlowHandler::MatchResult { err } => {
+            let handler_ty =
+                err.expr_ty(ctx).map(|ty| make_ty(&ty, ctx, module)).unwrap_or_else(make::ty_unit);
+            make::ty_generic(
+                make::name_ref("Result"),
+                vec![fun_ty.make_ty(ctx, module), handler_ty],
+            )
+        }
+    };
+    Some(make::ret_type(ret_ty))
+}
+
+fn make_body(
+    ctx: &AssistContext,
+    old_indent: IndentLevel,
+    new_indent: IndentLevel,
+    fun: &Function,
+) -> ast::BlockExpr {
+    let ret_ty = fun.return_type(ctx);
+    let handler = FlowHandler::from_ret_ty(fun, &ret_ty);
+    let block = match &fun.body {
+        FunctionBody::Expr(expr) => {
+            let expr = rewrite_body_segment(ctx, &fun.params, &handler, expr.syntax());
+            let expr = ast::Expr::cast(expr).unwrap();
+            let expr = expr.dedent(old_indent).indent(IndentLevel(1));
+
+            make::block_expr(Vec::new(), Some(expr))
+        }
+        FunctionBody::Span { parent, text_range } => {
+            let mut elements: Vec<_> = parent
+                .syntax()
+                .children()
+                .filter(|it| text_range.contains_range(it.text_range()))
+                .map(|it| rewrite_body_segment(ctx, &fun.params, &handler, &it))
+                .collect();
+
+            let mut tail_expr = match elements.pop() {
+                Some(node) => ast::Expr::cast(node.clone()).or_else(|| {
+                    elements.push(node);
+                    None
+                }),
+                None => None,
+            };
+
+            if tail_expr.is_none() {
+                match fun.vars_defined_in_body_and_outlive.as_slice() {
+                    [] => {}
+                    [var] => {
+                        tail_expr = Some(path_expr_from_local(ctx, *var));
+                    }
+                    vars => {
+                        let exprs = vars.iter().map(|var| path_expr_from_local(ctx, *var));
+                        let expr = make::expr_tuple(exprs);
+                        tail_expr = Some(expr);
+                    }
+                }
+            }
+
+            let elements = elements.into_iter().filter_map(|node| match ast::Stmt::cast(node) {
+                Some(stmt) => Some(stmt),
+                None => {
+                    stdx::never!("block contains non-statement");
+                    None
+                }
+            });
+
+            let body_indent = IndentLevel(1);
+            let elements = elements.map(|stmt| stmt.dedent(old_indent).indent(body_indent));
+            let tail_expr = tail_expr.map(|expr| expr.dedent(old_indent).indent(body_indent));
+
+            make::block_expr(elements, tail_expr)
+        }
+    };
+
+    let block = match &handler {
+        FlowHandler::None => block,
+        FlowHandler::Try { kind } => {
+            let block = with_default_tail_expr(block, make::expr_unit());
+            map_tail_expr(block, |tail_expr| {
+                let constructor = match kind {
+                    TryKind::Option => "Some",
+                    TryKind::Result { .. } => "Ok",
+                };
+                let func = make::expr_path(make_path_from_text(constructor));
+                let args = make::arg_list(iter::once(tail_expr));
+                make::expr_call(func, args)
+            })
+        }
+        FlowHandler::If { .. } => {
+            let lit_false = ast::Literal::cast(make::tokens::literal("false").parent()).unwrap();
+            with_tail_expr(block, lit_false.into())
+        }
+        FlowHandler::IfOption { .. } => {
+            let none = make::expr_path(make_path_from_text("None"));
+            with_tail_expr(block, none)
+        }
+        FlowHandler::MatchOption { .. } => map_tail_expr(block, |tail_expr| {
+            let some = make::expr_path(make_path_from_text("Some"));
+            let args = make::arg_list(iter::once(tail_expr));
+            make::expr_call(some, args)
+        }),
+        FlowHandler::MatchResult { .. } => map_tail_expr(block, |tail_expr| {
+            let ok = make::expr_path(make_path_from_text("Ok"));
+            let args = make::arg_list(iter::once(tail_expr));
+            make::expr_call(ok, args)
+        }),
+    };
+
+    block.indent(new_indent)
+}
+
+fn map_tail_expr(block: ast::BlockExpr, f: impl FnOnce(ast::Expr) -> ast::Expr) -> ast::BlockExpr {
+    let tail_expr = match block.tail_expr() {
+        Some(tail_expr) => tail_expr,
+        None => return block,
+    };
+    make::block_expr(block.statements(), Some(f(tail_expr)))
+}
+
+fn with_default_tail_expr(block: ast::BlockExpr, tail_expr: ast::Expr) -> ast::BlockExpr {
+    match block.tail_expr() {
+        Some(_) => block,
+        None => make::block_expr(block.statements(), Some(tail_expr)),
+    }
+}
+
+fn with_tail_expr(block: ast::BlockExpr, tail_expr: ast::Expr) -> ast::BlockExpr {
+    let stmt_tail = block.tail_expr().map(|expr| make::expr_stmt(expr).into());
+    let stmts = block.statements().chain(stmt_tail);
+    make::block_expr(stmts, Some(tail_expr))
+}
+
+fn format_type(ty: &hir::Type, ctx: &AssistContext, module: hir::Module) -> String {
+    ty.display_source_code(ctx.db(), module.into()).ok().unwrap_or_else(|| "()".to_string())
+}
+
+fn make_ty(ty: &hir::Type, ctx: &AssistContext, module: hir::Module) -> ast::Type {
+    let ty_str = format_type(ty, ctx, module);
+    make::ty(&ty_str)
+}
+
+fn rewrite_body_segment(
+    ctx: &AssistContext,
+    params: &[Param],
+    handler: &FlowHandler,
+    syntax: &SyntaxNode,
+) -> SyntaxNode {
+    let syntax = fix_param_usages(ctx, params, syntax);
+    update_external_control_flow(handler, &syntax)
+}
+
+/// change all usages to account for added `&`/`&mut` for some params
+fn fix_param_usages(ctx: &AssistContext, params: &[Param], syntax: &SyntaxNode) -> SyntaxNode {
+    let mut rewriter = SyntaxRewriter::default();
+    for param in params {
+        if !param.kind().is_ref() {
+            continue;
+        }
+
+        let usages = LocalUsages::find(ctx, param.var);
+        let usages = usages
+            .iter()
+            .filter(|reference| syntax.text_range().contains_range(reference.range))
+            .filter_map(|reference| path_element_of_reference(syntax, reference));
+        for path in usages {
+            match path.syntax().ancestors().skip(1).find_map(ast::Expr::cast) {
+                Some(ast::Expr::MethodCallExpr(_)) | Some(ast::Expr::FieldExpr(_)) => {
+                    // do nothing
+                }
+                Some(ast::Expr::RefExpr(node))
+                    if param.kind() == ParamKind::MutRef && node.mut_token().is_some() =>
+                {
+                    rewriter.replace_ast(&node.clone().into(), &node.expr().unwrap());
+                }
+                Some(ast::Expr::RefExpr(node))
+                    if param.kind() == ParamKind::SharedRef && node.mut_token().is_none() =>
+                {
+                    rewriter.replace_ast(&node.clone().into(), &node.expr().unwrap());
+                }
+                Some(_) | None => {
+                    rewriter.replace_ast(&path, &make::expr_prefix(T![*], path.clone()));
+                }
+            };
+        }
+    }
+
+    rewriter.rewrite(syntax)
+}
+
+fn update_external_control_flow(handler: &FlowHandler, syntax: &SyntaxNode) -> SyntaxNode {
+    let mut rewriter = SyntaxRewriter::default();
+
+    let mut nested_loop = None;
+    let mut nested_scope = None;
+    for event in syntax.preorder() {
+        let node = match event {
+            WalkEvent::Enter(e) => {
+                match e.kind() {
+                    SyntaxKind::LOOP_EXPR | SyntaxKind::WHILE_EXPR | SyntaxKind::FOR_EXPR => {
+                        if nested_loop.is_none() {
+                            nested_loop = Some(e.clone());
+                        }
+                    }
+                    SyntaxKind::FN
+                    | SyntaxKind::CONST
+                    | SyntaxKind::STATIC
+                    | SyntaxKind::IMPL
+                    | SyntaxKind::MODULE => {
+                        if nested_scope.is_none() {
+                            nested_scope = Some(e.clone());
+                        }
+                    }
+                    _ => {}
+                }
+                e
+            }
+            WalkEvent::Leave(e) => {
+                if nested_loop.as_ref() == Some(&e) {
+                    nested_loop = None;
+                }
+                if nested_scope.as_ref() == Some(&e) {
+                    nested_scope = None;
+                }
+                continue;
+            }
+        };
+        if nested_scope.is_some() {
+            continue;
+        }
+        let expr = match ast::Expr::cast(node) {
+            Some(e) => e,
+            None => continue,
+        };
+        match expr {
+            ast::Expr::ReturnExpr(return_expr) if nested_scope.is_none() => {
+                let expr = return_expr.expr();
+                if let Some(replacement) = make_rewritten_flow(handler, expr) {
+                    rewriter.replace_ast(&return_expr.into(), &replacement);
+                }
+            }
+            ast::Expr::BreakExpr(break_expr) if nested_loop.is_none() => {
+                let expr = break_expr.expr();
+                if let Some(replacement) = make_rewritten_flow(handler, expr) {
+                    rewriter.replace_ast(&break_expr.into(), &replacement);
+                }
+            }
+            ast::Expr::ContinueExpr(continue_expr) if nested_loop.is_none() => {
+                if let Some(replacement) = make_rewritten_flow(handler, None) {
+                    rewriter.replace_ast(&continue_expr.into(), &replacement);
+                }
+            }
+            _ => {
+                // do nothing
+            }
+        }
+    }
+
+    rewriter.rewrite(syntax)
+}
+
+fn make_rewritten_flow(handler: &FlowHandler, arg_expr: Option<ast::Expr>) -> Option<ast::Expr> {
+    let value = match handler {
+        FlowHandler::None | FlowHandler::Try { .. } => return None,
+        FlowHandler::If { .. } => {
+            ast::Literal::cast(make::tokens::literal("true").parent()).unwrap().into()
+        }
+        FlowHandler::IfOption { .. } => {
+            let expr = arg_expr.unwrap_or_else(|| make::expr_tuple(Vec::new()));
+            let args = make::arg_list(iter::once(expr));
+            make::expr_call(make::expr_path(make_path_from_text("Some")), args)
+        }
+        FlowHandler::MatchOption { .. } => make::expr_path(make_path_from_text("None")),
+        FlowHandler::MatchResult { .. } => {
+            let expr = arg_expr.unwrap_or_else(|| make::expr_tuple(Vec::new()));
+            let args = make::arg_list(iter::once(expr));
+            make::expr_call(make::expr_path(make_path_from_text("Err")), args)
+        }
+    };
+    Some(make::expr_return(Some(value)))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn no_args_from_binary_expr() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    foo($01 + 1$0);
+}"#,
+            r#"
+fn foo() {
+    foo(fun_name());
+}
+
+fn $0fun_name() -> i32 {
+    1 + 1
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_from_binary_expr_in_module() {
+        check_assist(
+            extract_function,
+            r#"
+mod bar {
+    fn foo() {
+        foo($01 + 1$0);
+    }
+}"#,
+            r#"
+mod bar {
+    fn foo() {
+        foo(fun_name());
+    }
+
+    fn $0fun_name() -> i32 {
+        1 + 1
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_from_binary_expr_indented() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    $0{ 1 + 1 }$0;
+}"#,
+            r#"
+fn foo() {
+    fun_name();
+}
+
+fn $0fun_name() -> i32 {
+    { 1 + 1 }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_from_stmt_with_last_expr() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() -> i32 {
+    let k = 1;
+    $0let m = 1;
+    m + 1$0
+}"#,
+            r#"
+fn foo() -> i32 {
+    let k = 1;
+    fun_name()
+}
+
+fn $0fun_name() -> i32 {
+    let m = 1;
+    m + 1
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_from_stmt_unit() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    let k = 3;
+    $0let m = 1;
+    let n = m + 1;$0
+    let g = 5;
+}"#,
+            r#"
+fn foo() {
+    let k = 3;
+    fun_name();
+    let g = 5;
+}
+
+fn $0fun_name() {
+    let m = 1;
+    let n = m + 1;
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_if() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    $0if true { }$0
+}"#,
+            r#"
+fn foo() {
+    fun_name();
+}
+
+fn $0fun_name() {
+    if true { }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_if_else() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() -> i32 {
+    $0if true { 1 } else { 2 }$0
+}"#,
+            r#"
+fn foo() -> i32 {
+    fun_name()
+}
+
+fn $0fun_name() -> i32 {
+    if true { 1 } else { 2 }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_if_let_else() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() -> i32 {
+    $0if let true = false { 1 } else { 2 }$0
+}"#,
+            r#"
+fn foo() -> i32 {
+    fun_name()
+}
+
+fn $0fun_name() -> i32 {
+    if let true = false { 1 } else { 2 }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_match() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() -> i32 {
+    $0match true {
+        true => 1,
+        false => 2,
+    }$0
+}"#,
+            r#"
+fn foo() -> i32 {
+    fun_name()
+}
+
+fn $0fun_name() -> i32 {
+    match true {
+        true => 1,
+        false => 2,
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_while() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    $0while true { }$0
+}"#,
+            r#"
+fn foo() {
+    fun_name();
+}
+
+fn $0fun_name() {
+    while true { }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_for() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    $0for v in &[0, 1] { }$0
+}"#,
+            r#"
+fn foo() {
+    fun_name();
+}
+
+fn $0fun_name() {
+    for v in &[0, 1] { }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_from_loop_unit() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    $0loop {
+        let m = 1;
+    }$0
+}"#,
+            r#"
+fn foo() {
+    fun_name()
+}
+
+fn $0fun_name() -> ! {
+    loop {
+        let m = 1;
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_from_loop_with_return() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    let v = $0loop {
+        let m = 1;
+        break m;
+    }$0;
+}"#,
+            r#"
+fn foo() {
+    let v = fun_name();
+}
+
+fn $0fun_name() -> i32 {
+    loop {
+        let m = 1;
+        break m;
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn no_args_from_match() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    let v: i32 = $0match Some(1) {
+        Some(x) => x,
+        None => 0,
+    }$0;
+}"#,
+            r#"
+fn foo() {
+    let v: i32 = fun_name();
+}
+
+fn $0fun_name() -> i32 {
+    match Some(1) {
+        Some(x) => x,
+        None => 0,
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn argument_form_expr() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() -> u32 {
+    let n = 2;
+    $0n+2$0
+}",
+            r"
+fn foo() -> u32 {
+    let n = 2;
+    fun_name(n)
+}
+
+fn $0fun_name(n: u32) -> u32 {
+    n+2
+}",
+        )
+    }
+
+    #[test]
+    fn argument_used_twice_form_expr() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() -> u32 {
+    let n = 2;
+    $0n+n$0
+}",
+            r"
+fn foo() -> u32 {
+    let n = 2;
+    fun_name(n)
+}
+
+fn $0fun_name(n: u32) -> u32 {
+    n+n
+}",
+        )
+    }
+
+    #[test]
+    fn two_arguments_form_expr() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() -> u32 {
+    let n = 2;
+    let m = 3;
+    $0n+n*m$0
+}",
+            r"
+fn foo() -> u32 {
+    let n = 2;
+    let m = 3;
+    fun_name(n, m)
+}
+
+fn $0fun_name(n: u32, m: u32) -> u32 {
+    n+n*m
+}",
+        )
+    }
+
+    #[test]
+    fn argument_and_locals() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() -> u32 {
+    let n = 2;
+    $0let m = 1;
+    n + m$0
+}",
+            r"
+fn foo() -> u32 {
+    let n = 2;
+    fun_name(n)
+}
+
+fn $0fun_name(n: u32) -> u32 {
+    let m = 1;
+    n + m
+}",
+        )
+    }
+
+    #[test]
+    fn in_comment_is_not_applicable() {
+        mark::check!(extract_function_in_comment_is_not_applicable);
+        check_assist_not_applicable(extract_function, r"fn main() { 1 + /* $0comment$0 */ 1; }");
+    }
+
+    #[test]
+    fn part_of_expr_stmt() {
+        check_assist(
+            extract_function,
+            "
+fn foo() {
+    $01$0 + 1;
+}",
+            "
+fn foo() {
+    fun_name() + 1;
+}
+
+fn $0fun_name() -> i32 {
+    1
+}",
+        );
+    }
+
+    #[test]
+    fn function_expr() {
+        check_assist(
+            extract_function,
+            r#"
+fn foo() {
+    $0bar(1 + 1)$0
+}"#,
+            r#"
+fn foo() {
+    fun_name();
+}
+
+fn $0fun_name() {
+    bar(1 + 1)
+}"#,
+        )
+    }
+
+    #[test]
+    fn extract_from_nested() {
+        check_assist(
+            extract_function,
+            r"
+fn main() {
+    let x = true;
+    let tuple = match x {
+        true => ($02 + 2$0, true)
+        _ => (0, false)
+    };
+}",
+            r"
+fn main() {
+    let x = true;
+    let tuple = match x {
+        true => (fun_name(), true)
+        _ => (0, false)
+    };
+}
+
+fn $0fun_name() -> i32 {
+    2 + 2
+}",
+        );
+    }
+
+    #[test]
+    fn param_from_closure() {
+        check_assist(
+            extract_function,
+            r"
+fn main() {
+    let lambda = |x: u32| $0x * 2$0;
+}",
+            r"
+fn main() {
+    let lambda = |x: u32| fun_name(x);
+}
+
+fn $0fun_name(x: u32) -> u32 {
+    x * 2
+}",
+        );
+    }
+
+    #[test]
+    fn extract_return_stmt() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() -> u32 {
+    $0return 2 + 2$0;
+}",
+            r"
+fn foo() -> u32 {
+    return fun_name();
+}
+
+fn $0fun_name() -> u32 {
+    2 + 2
+}",
+        );
+    }
+
+    #[test]
+    fn does_not_add_extra_whitespace() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() -> u32 {
+
+
+    $0return 2 + 2$0;
+}",
+            r"
+fn foo() -> u32 {
+
+
+    return fun_name();
+}
+
+fn $0fun_name() -> u32 {
+    2 + 2
+}",
+        );
+    }
+
+    #[test]
+    fn break_stmt() {
+        check_assist(
+            extract_function,
+            r"
+fn main() {
+    let result = loop {
+        $0break 2 + 2$0;
+    };
+}",
+            r"
+fn main() {
+    let result = loop {
+        break fun_name();
+    };
+}
+
+fn $0fun_name() -> i32 {
+    2 + 2
+}",
+        );
+    }
+
+    #[test]
+    fn extract_cast() {
+        check_assist(
+            extract_function,
+            r"
+fn main() {
+    let v = $00f32 as u32$0;
+}",
+            r"
+fn main() {
+    let v = fun_name();
+}
+
+fn $0fun_name() -> u32 {
+    0f32 as u32
+}",
+        );
+    }
+
+    #[test]
+    fn return_not_applicable() {
+        check_assist_not_applicable(extract_function, r"fn foo() { $0return$0; } ");
+    }
+
+    #[test]
+    fn method_to_freestanding() {
+        check_assist(
+            extract_function,
+            r"
+struct S;
+
+impl S {
+    fn foo(&self) -> i32 {
+        $01+1$0
+    }
+}",
+            r"
+struct S;
+
+impl S {
+    fn foo(&self) -> i32 {
+        fun_name()
+    }
+}
+
+fn $0fun_name() -> i32 {
+    1+1
+}",
+        );
+    }
+
+    #[test]
+    fn method_with_reference() {
+        check_assist(
+            extract_function,
+            r"
+struct S { f: i32 };
+
+impl S {
+    fn foo(&self) -> i32 {
+        $01+self.f$0
+    }
+}",
+            r"
+struct S { f: i32 };
+
+impl S {
+    fn foo(&self) -> i32 {
+        self.fun_name()
+    }
+
+    fn $0fun_name(&self) -> i32 {
+        1+self.f
+    }
+}",
+        );
+    }
+
+    #[test]
+    fn method_with_mut() {
+        check_assist(
+            extract_function,
+            r"
+struct S { f: i32 };
+
+impl S {
+    fn foo(&mut self) {
+        $0self.f += 1;$0
+    }
+}",
+            r"
+struct S { f: i32 };
+
+impl S {
+    fn foo(&mut self) {
+        self.fun_name();
+    }
+
+    fn $0fun_name(&mut self) {
+        self.f += 1;
+    }
+}",
+        );
+    }
+
+    #[test]
+    fn variable_defined_inside_and_used_after_no_ret() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    let n = 1;
+    $0let k = n * n;$0
+    let m = k + 1;
+}",
+            r"
+fn foo() {
+    let n = 1;
+    let k = fun_name(n);
+    let m = k + 1;
+}
+
+fn $0fun_name(n: i32) -> i32 {
+    let k = n * n;
+    k
+}",
+        );
+    }
+
+    #[test]
+    fn two_variables_defined_inside_and_used_after_no_ret() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    let n = 1;
+    $0let k = n * n;
+    let m = k + 2;$0
+    let h = k + m;
+}",
+            r"
+fn foo() {
+    let n = 1;
+    let (k, m) = fun_name(n);
+    let h = k + m;
+}
+
+fn $0fun_name(n: i32) -> (i32, i32) {
+    let k = n * n;
+    let m = k + 2;
+    (k, m)
+}",
+        );
+    }
+
+    #[test]
+    fn nontrivial_patterns_define_variables() {
+        check_assist(
+            extract_function,
+            r"
+struct Counter(i32);
+fn foo() {
+    $0let Counter(n) = Counter(0);$0
+    let m = n;
+}",
+            r"
+struct Counter(i32);
+fn foo() {
+    let n = fun_name();
+    let m = n;
+}
+
+fn $0fun_name() -> i32 {
+    let Counter(n) = Counter(0);
+    n
+}",
+        );
+    }
+
+    #[test]
+    fn struct_with_two_fields_pattern_define_variables() {
+        check_assist(
+            extract_function,
+            r"
+struct Counter { n: i32, m: i32 };
+fn foo() {
+    $0let Counter { n, m: k } = Counter { n: 1, m: 2 };$0
+    let h = n + k;
+}",
+            r"
+struct Counter { n: i32, m: i32 };
+fn foo() {
+    let (n, k) = fun_name();
+    let h = n + k;
+}
+
+fn $0fun_name() -> (i32, i32) {
+    let Counter { n, m: k } = Counter { n: 1, m: 2 };
+    (n, k)
+}",
+        );
+    }
+
+    #[test]
+    fn mut_var_from_outer_scope() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    let mut n = 1;
+    $0n += 1;$0
+    let m = n + 1;
+}",
+            r"
+fn foo() {
+    let mut n = 1;
+    fun_name(&mut n);
+    let m = n + 1;
+}
+
+fn $0fun_name(n: &mut i32) {
+    *n += 1;
+}",
+        );
+    }
+
+    #[test]
+    fn mut_field_from_outer_scope() {
+        check_assist(
+            extract_function,
+            r"
+struct C { n: i32 }
+fn foo() {
+    let mut c = C { n: 0 };
+    $0c.n += 1;$0
+    let m = c.n + 1;
+}",
+            r"
+struct C { n: i32 }
+fn foo() {
+    let mut c = C { n: 0 };
+    fun_name(&mut c);
+    let m = c.n + 1;
+}
+
+fn $0fun_name(c: &mut C) {
+    c.n += 1;
+}",
+        );
+    }
+
+    #[test]
+    fn mut_nested_field_from_outer_scope() {
+        check_assist(
+            extract_function,
+            r"
+struct P { n: i32}
+struct C { p: P }
+fn foo() {
+    let mut c = C { p: P { n: 0 } };
+    let mut v = C { p: P { n: 0 } };
+    let u = C { p: P { n: 0 } };
+    $0c.p.n += u.p.n;
+    let r = &mut v.p.n;$0
+    let m = c.p.n + v.p.n + u.p.n;
+}",
+            r"
+struct P { n: i32}
+struct C { p: P }
+fn foo() {
+    let mut c = C { p: P { n: 0 } };
+    let mut v = C { p: P { n: 0 } };
+    let u = C { p: P { n: 0 } };
+    fun_name(&mut c, &u, &mut v);
+    let m = c.p.n + v.p.n + u.p.n;
+}
+
+fn $0fun_name(c: &mut C, u: &C, v: &mut C) {
+    c.p.n += u.p.n;
+    let r = &mut v.p.n;
+}",
+        );
+    }
+
+    #[test]
+    fn mut_param_many_usages_stmt() {
+        check_assist(
+            extract_function,
+            r"
+fn bar(k: i32) {}
+trait I: Copy {
+    fn succ(&self) -> Self;
+    fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
+}
+impl I for i32 {
+    fn succ(&self) -> Self { *self + 1 }
+}
+fn foo() {
+    let mut n = 1;
+    $0n += n;
+    bar(n);
+    bar(n+1);
+    bar(n*n);
+    bar(&n);
+    n.inc();
+    let v = &mut n;
+    *v = v.succ();
+    n.succ();$0
+    let m = n + 1;
+}",
+            r"
+fn bar(k: i32) {}
+trait I: Copy {
+    fn succ(&self) -> Self;
+    fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
+}
+impl I for i32 {
+    fn succ(&self) -> Self { *self + 1 }
+}
+fn foo() {
+    let mut n = 1;
+    fun_name(&mut n);
+    let m = n + 1;
+}
+
+fn $0fun_name(n: &mut i32) {
+    *n += *n;
+    bar(*n);
+    bar(*n+1);
+    bar(*n**n);
+    bar(&*n);
+    n.inc();
+    let v = n;
+    *v = v.succ();
+    n.succ();
+}",
+        );
+    }
+
+    #[test]
+    fn mut_param_many_usages_expr() {
+        check_assist(
+            extract_function,
+            r"
+fn bar(k: i32) {}
+trait I: Copy {
+    fn succ(&self) -> Self;
+    fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
+}
+impl I for i32 {
+    fn succ(&self) -> Self { *self + 1 }
+}
+fn foo() {
+    let mut n = 1;
+    $0{
+        n += n;
+        bar(n);
+        bar(n+1);
+        bar(n*n);
+        bar(&n);
+        n.inc();
+        let v = &mut n;
+        *v = v.succ();
+        n.succ();
+    }$0
+    let m = n + 1;
+}",
+            r"
+fn bar(k: i32) {}
+trait I: Copy {
+    fn succ(&self) -> Self;
+    fn inc(&mut self) -> Self { let v = self.succ(); *self = v; v }
+}
+impl I for i32 {
+    fn succ(&self) -> Self { *self + 1 }
+}
+fn foo() {
+    let mut n = 1;
+    fun_name(&mut n);
+    let m = n + 1;
+}
+
+fn $0fun_name(n: &mut i32) {
+    {
+        *n += *n;
+        bar(*n);
+        bar(*n+1);
+        bar(*n**n);
+        bar(&*n);
+        n.inc();
+        let v = n;
+        *v = v.succ();
+        n.succ();
+    }
+}",
+        );
+    }
+
+    #[test]
+    fn mut_param_by_value() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    let mut n = 1;
+    $0n += 1;$0
+}",
+            r"
+fn foo() {
+    let mut n = 1;
+    fun_name(n);
+}
+
+fn $0fun_name(mut n: i32) {
+    n += 1;
+}",
+        );
+    }
+
+    #[test]
+    fn mut_param_because_of_mut_ref() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    let mut n = 1;
+    $0let v = &mut n;
+    *v += 1;$0
+    let k = n;
+}",
+            r"
+fn foo() {
+    let mut n = 1;
+    fun_name(&mut n);
+    let k = n;
+}
+
+fn $0fun_name(n: &mut i32) {
+    let v = n;
+    *v += 1;
+}",
+        );
+    }
+
+    #[test]
+    fn mut_param_by_value_because_of_mut_ref() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    let mut n = 1;
+    $0let v = &mut n;
+    *v += 1;$0
+}",
+            r"
+fn foo() {
+    let mut n = 1;
+    fun_name(n);
+}
+
+fn $0fun_name(mut n: i32) {
+    let v = &mut n;
+    *v += 1;
+}",
+        );
+    }
+
+    #[test]
+    fn mut_method_call() {
+        check_assist(
+            extract_function,
+            r"
+trait I {
+    fn inc(&mut self);
+}
+impl I for i32 {
+    fn inc(&mut self) { *self += 1 }
+}
+fn foo() {
+    let mut n = 1;
+    $0n.inc();$0
+}",
+            r"
+trait I {
+    fn inc(&mut self);
+}
+impl I for i32 {
+    fn inc(&mut self) { *self += 1 }
+}
+fn foo() {
+    let mut n = 1;
+    fun_name(n);
+}
+
+fn $0fun_name(mut n: i32) {
+    n.inc();
+}",
+        );
+    }
+
+    #[test]
+    fn shared_method_call() {
+        check_assist(
+            extract_function,
+            r"
+trait I {
+    fn succ(&self);
+}
+impl I for i32 {
+    fn succ(&self) { *self + 1 }
+}
+fn foo() {
+    let mut n = 1;
+    $0n.succ();$0
+}",
+            r"
+trait I {
+    fn succ(&self);
+}
+impl I for i32 {
+    fn succ(&self) { *self + 1 }
+}
+fn foo() {
+    let mut n = 1;
+    fun_name(n);
+}
+
+fn $0fun_name(n: i32) {
+    n.succ();
+}",
+        );
+    }
+
+    #[test]
+    fn mut_method_call_with_other_receiver() {
+        check_assist(
+            extract_function,
+            r"
+trait I {
+    fn inc(&mut self, n: i32);
+}
+impl I for i32 {
+    fn inc(&mut self, n: i32) { *self += n }
+}
+fn foo() {
+    let mut n = 1;
+    $0let mut m = 2;
+    m.inc(n);$0
+}",
+            r"
+trait I {
+    fn inc(&mut self, n: i32);
+}
+impl I for i32 {
+    fn inc(&mut self, n: i32) { *self += n }
+}
+fn foo() {
+    let mut n = 1;
+    fun_name(n);
+}
+
+fn $0fun_name(n: i32) {
+    let mut m = 2;
+    m.inc(n);
+}",
+        );
+    }
+
+    #[test]
+    fn non_copy_without_usages_after() {
+        check_assist(
+            extract_function,
+            r"
+struct Counter(i32);
+fn foo() {
+    let c = Counter(0);
+    $0let n = c.0;$0
+}",
+            r"
+struct Counter(i32);
+fn foo() {
+    let c = Counter(0);
+    fun_name(c);
+}
+
+fn $0fun_name(c: Counter) {
+    let n = c.0;
+}",
+        );
+    }
+
+    #[test]
+    fn non_copy_used_after() {
+        check_assist(
+            extract_function,
+            r"
+struct Counter(i32);
+fn foo() {
+    let c = Counter(0);
+    $0let n = c.0;$0
+    let m = c.0;
+}",
+            r"
+struct Counter(i32);
+fn foo() {
+    let c = Counter(0);
+    fun_name(&c);
+    let m = c.0;
+}
+
+fn $0fun_name(c: &Counter) {
+    let n = c.0;
+}",
+        );
+    }
+
+    #[test]
+    fn copy_used_after() {
+        check_assist(
+            extract_function,
+            r##"
+#[lang = "copy"]
+pub trait Copy {}
+impl Copy for i32 {}
+fn foo() {
+    let n = 0;
+    $0let m = n;$0
+    let k = n;
+}"##,
+            r##"
+#[lang = "copy"]
+pub trait Copy {}
+impl Copy for i32 {}
+fn foo() {
+    let n = 0;
+    fun_name(n);
+    let k = n;
+}
+
+fn $0fun_name(n: i32) {
+    let m = n;
+}"##,
+        )
+    }
+
+    #[test]
+    fn copy_custom_used_after() {
+        check_assist(
+            extract_function,
+            r##"
+#[lang = "copy"]
+pub trait Copy {}
+struct Counter(i32);
+impl Copy for Counter {}
+fn foo() {
+    let c = Counter(0);
+    $0let n = c.0;$0
+    let m = c.0;
+}"##,
+            r##"
+#[lang = "copy"]
+pub trait Copy {}
+struct Counter(i32);
+impl Copy for Counter {}
+fn foo() {
+    let c = Counter(0);
+    fun_name(c);
+    let m = c.0;
+}
+
+fn $0fun_name(c: Counter) {
+    let n = c.0;
+}"##,
+        );
+    }
+
+    #[test]
+    fn indented_stmts() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    if true {
+        loop {
+            $0let n = 1;
+            let m = 2;$0
+        }
+    }
+}",
+            r"
+fn foo() {
+    if true {
+        loop {
+            fun_name();
+        }
+    }
+}
+
+fn $0fun_name() {
+    let n = 1;
+    let m = 2;
+}",
+        );
+    }
+
+    #[test]
+    fn indented_stmts_inside_mod() {
+        check_assist(
+            extract_function,
+            r"
+mod bar {
+    fn foo() {
+        if true {
+            loop {
+                $0let n = 1;
+                let m = 2;$0
+            }
+        }
+    }
+}",
+            r"
+mod bar {
+    fn foo() {
+        if true {
+            loop {
+                fun_name();
+            }
+        }
+    }
+
+    fn $0fun_name() {
+        let n = 1;
+        let m = 2;
+    }
+}",
+        );
+    }
+
+    #[test]
+    fn break_loop() {
+        check_assist(
+            extract_function,
+            r##"
+enum Option<T> {
+    #[lang = "None"] None,
+    #[lang = "Some"] Some(T),
+}
+use Option::*;
+fn foo() {
+    loop {
+        let n = 1;
+        $0let m = n + 1;
+        break;
+        let k = 2;$0
+        let h = 1 + k;
+    }
+}"##,
+            r##"
+enum Option<T> {
+    #[lang = "None"] None,
+    #[lang = "Some"] Some(T),
+}
+use Option::*;
+fn foo() {
+    loop {
+        let n = 1;
+        let k = match fun_name(n) {
+            Some(value) => value,
+            None => break,
+        };
+        let h = 1 + k;
+    }
+}
+
+fn $0fun_name(n: i32) -> Option<i32> {
+    let m = n + 1;
+    return None;
+    let k = 2;
+    Some(k)
+}"##,
+        );
+    }
+
+    #[test]
+    fn return_to_parent() {
+        check_assist(
+            extract_function,
+            r##"
+#[lang = "copy"]
+pub trait Copy {}
+impl Copy for i32 {}
+enum Result<T, E> {
+    #[lang = "Ok"] Ok(T),
+    #[lang = "Err"] Err(E),
+}
+use Result::*;
+fn foo() -> i64 {
+    let n = 1;
+    $0let m = n + 1;
+    return 1;
+    let k = 2;$0
+    (n + k) as i64
+}"##,
+            r##"
+#[lang = "copy"]
+pub trait Copy {}
+impl Copy for i32 {}
+enum Result<T, E> {
+    #[lang = "Ok"] Ok(T),
+    #[lang = "Err"] Err(E),
+}
+use Result::*;
+fn foo() -> i64 {
+    let n = 1;
+    let k = match fun_name(n) {
+        Ok(value) => value,
+        Err(value) => return value,
+    };
+    (n + k) as i64
+}
+
+fn $0fun_name(n: i32) -> Result<i32, i64> {
+    let m = n + 1;
+    return Err(1);
+    let k = 2;
+    Ok(k)
+}"##,
+        );
+    }
+
+    #[test]
+    fn break_and_continue() {
+        mark::check!(external_control_flow_break_and_continue);
+        check_assist_not_applicable(
+            extract_function,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        $0let m = n + 1;
+        break;
+        let k = 2;
+        continue;
+        let k = k + 1;$0
+        let r = n + k;
+    }
+}"##,
+        );
+    }
+
+    #[test]
+    fn return_and_break() {
+        mark::check!(external_control_flow_return_and_bc);
+        check_assist_not_applicable(
+            extract_function,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        $0let m = n + 1;
+        break;
+        let k = 2;
+        return;
+        let k = k + 1;$0
+        let r = n + k;
+    }
+}"##,
+        );
+    }
+
+    #[test]
+    fn break_loop_with_if() {
+        check_assist(
+            extract_function,
+            r##"
+fn foo() {
+    loop {
+        let mut n = 1;
+        $0let m = n + 1;
+        break;
+        n += m;$0
+        let h = 1 + n;
+    }
+}"##,
+            r##"
+fn foo() {
+    loop {
+        let mut n = 1;
+        if fun_name(&mut n) {
+            break;
+        }
+        let h = 1 + n;
+    }
+}
+
+fn $0fun_name(n: &mut i32) -> bool {
+    let m = *n + 1;
+    return true;
+    *n += m;
+    false
+}"##,
+        );
+    }
+
+    #[test]
+    fn break_loop_nested() {
+        check_assist(
+            extract_function,
+            r##"
+fn foo() {
+    loop {
+        let mut n = 1;
+        $0let m = n + 1;
+        if m == 42 {
+            break;
+        }$0
+        let h = 1;
+    }
+}"##,
+            r##"
+fn foo() {
+    loop {
+        let mut n = 1;
+        if fun_name(n) {
+            break;
+        }
+        let h = 1;
+    }
+}
+
+fn $0fun_name(n: i32) -> bool {
+    let m = n + 1;
+    if m == 42 {
+        return true;
+    }
+    false
+}"##,
+        );
+    }
+
+    #[test]
+    fn return_from_nested_loop() {
+        check_assist(
+            extract_function,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        $0
+        let k = 1;
+        loop {
+            return;
+        }
+        let m = k + 1;$0
+        let h = 1 + m;
+    }
+}"##,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        let m = match fun_name() {
+            Some(value) => value,
+            None => return,
+        };
+        let h = 1 + m;
+    }
+}
+
+fn $0fun_name() -> Option<i32> {
+    let k = 1;
+    loop {
+        return None;
+    }
+    let m = k + 1;
+    Some(m)
+}"##,
+        );
+    }
+
+    #[test]
+    fn break_from_nested_loop() {
+        check_assist(
+            extract_function,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        $0let k = 1;
+        loop {
+            break;
+        }
+        let m = k + 1;$0
+        let h = 1 + m;
+    }
+}"##,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        let m = fun_name();
+        let h = 1 + m;
+    }
+}
+
+fn $0fun_name() -> i32 {
+    let k = 1;
+    loop {
+        break;
+    }
+    let m = k + 1;
+    m
+}"##,
+        );
+    }
+
+    #[test]
+    fn break_from_nested_and_outer_loops() {
+        check_assist(
+            extract_function,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        $0let k = 1;
+        loop {
+            break;
+        }
+        if k == 42 {
+            break;
+        }
+        let m = k + 1;$0
+        let h = 1 + m;
+    }
+}"##,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        let m = match fun_name() {
+            Some(value) => value,
+            None => break,
+        };
+        let h = 1 + m;
+    }
+}
+
+fn $0fun_name() -> Option<i32> {
+    let k = 1;
+    loop {
+        break;
+    }
+    if k == 42 {
+        return None;
+    }
+    let m = k + 1;
+    Some(m)
+}"##,
+        );
+    }
+
+    #[test]
+    fn return_from_nested_fn() {
+        check_assist(
+            extract_function,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        $0let k = 1;
+        fn test() {
+            return;
+        }
+        let m = k + 1;$0
+        let h = 1 + m;
+    }
+}"##,
+            r##"
+fn foo() {
+    loop {
+        let n = 1;
+        let m = fun_name();
+        let h = 1 + m;
+    }
+}
+
+fn $0fun_name() -> i32 {
+    let k = 1;
+    fn test() {
+        return;
+    }
+    let m = k + 1;
+    m
+}"##,
+        );
+    }
+
+    #[test]
+    fn break_with_value() {
+        check_assist(
+            extract_function,
+            r##"
+fn foo() -> i32 {
+    loop {
+        let n = 1;
+        $0let k = 1;
+        if k == 42 {
+            break 3;
+        }
+        let m = k + 1;$0
+        let h = 1;
+    }
+}"##,
+            r##"
+fn foo() -> i32 {
+    loop {
+        let n = 1;
+        if let Some(value) = fun_name() {
+            break value;
+        }
+        let h = 1;
+    }
+}
+
+fn $0fun_name() -> Option<i32> {
+    let k = 1;
+    if k == 42 {
+        return Some(3);
+    }
+    let m = k + 1;
+    None
+}"##,
+        );
+    }
+
+    #[test]
+    fn break_with_value_and_return() {
+        check_assist(
+            extract_function,
+            r##"
+fn foo() -> i64 {
+    loop {
+        let n = 1;
+        $0
+        let k = 1;
+        if k == 42 {
+            break 3;
+        }
+        let m = k + 1;$0
+        let h = 1 + m;
+    }
+}"##,
+            r##"
+fn foo() -> i64 {
+    loop {
+        let n = 1;
+        let m = match fun_name() {
+            Ok(value) => value,
+            Err(value) => break value,
+        };
+        let h = 1 + m;
+    }
+}
+
+fn $0fun_name() -> Result<i32, i64> {
+    let k = 1;
+    if k == 42 {
+        return Err(3);
+    }
+    let m = k + 1;
+    Ok(m)
+}"##,
+        );
+    }
+
+    #[test]
+    fn try_option() {
+        check_assist(
+            extract_function,
+            r##"
+enum Option<T> { None, Some(T), }
+use Option::*;
+fn bar() -> Option<i32> { None }
+fn foo() -> Option<()> {
+    let n = bar()?;
+    $0let k = foo()?;
+    let m = k + 1;$0
+    let h = 1 + m;
+    Some(())
+}"##,
+            r##"
+enum Option<T> { None, Some(T), }
+use Option::*;
+fn bar() -> Option<i32> { None }
+fn foo() -> Option<()> {
+    let n = bar()?;
+    let m = fun_name()?;
+    let h = 1 + m;
+    Some(())
+}
+
+fn $0fun_name() -> Option<i32> {
+    let k = foo()?;
+    let m = k + 1;
+    Some(m)
+}"##,
+        );
+    }
+
+    #[test]
+    fn try_option_unit() {
+        check_assist(
+            extract_function,
+            r##"
+enum Option<T> { None, Some(T), }
+use Option::*;
+fn foo() -> Option<()> {
+    let n = 1;
+    $0let k = foo()?;
+    let m = k + 1;$0
+    let h = 1 + n;
+    Some(())
+}"##,
+            r##"
+enum Option<T> { None, Some(T), }
+use Option::*;
+fn foo() -> Option<()> {
+    let n = 1;
+    fun_name()?;
+    let h = 1 + n;
+    Some(())
+}
+
+fn $0fun_name() -> Option<()> {
+    let k = foo()?;
+    let m = k + 1;
+    Some(())
+}"##,
+        );
+    }
+
+    #[test]
+    fn try_result() {
+        check_assist(
+            extract_function,
+            r##"
+enum Result<T, E> { Ok(T), Err(E), }
+use Result::*;
+fn foo() -> Result<(), i64> {
+    let n = 1;
+    $0let k = foo()?;
+    let m = k + 1;$0
+    let h = 1 + m;
+    Ok(())
+}"##,
+            r##"
+enum Result<T, E> { Ok(T), Err(E), }
+use Result::*;
+fn foo() -> Result<(), i64> {
+    let n = 1;
+    let m = fun_name()?;
+    let h = 1 + m;
+    Ok(())
+}
+
+fn $0fun_name() -> Result<i32, i64> {
+    let k = foo()?;
+    let m = k + 1;
+    Ok(m)
+}"##,
+        );
+    }
+
+    #[test]
+    fn try_option_with_return() {
+        check_assist(
+            extract_function,
+            r##"
+enum Option<T> { None, Some(T) }
+use Option::*;
+fn foo() -> Option<()> {
+    let n = 1;
+    $0let k = foo()?;
+    if k == 42 {
+        return None;
+    }
+    let m = k + 1;$0
+    let h = 1 + m;
+    Some(())
+}"##,
+            r##"
+enum Option<T> { None, Some(T) }
+use Option::*;
+fn foo() -> Option<()> {
+    let n = 1;
+    let m = fun_name()?;
+    let h = 1 + m;
+    Some(())
+}
+
+fn $0fun_name() -> Option<i32> {
+    let k = foo()?;
+    if k == 42 {
+        return None;
+    }
+    let m = k + 1;
+    Some(m)
+}"##,
+        );
+    }
+
+    #[test]
+    fn try_result_with_return() {
+        check_assist(
+            extract_function,
+            r##"
+enum Result<T, E> { Ok(T), Err(E), }
+use Result::*;
+fn foo() -> Result<(), i64> {
+    let n = 1;
+    $0let k = foo()?;
+    if k == 42 {
+        return Err(1);
+    }
+    let m = k + 1;$0
+    let h = 1 + m;
+    Ok(())
+}"##,
+            r##"
+enum Result<T, E> { Ok(T), Err(E), }
+use Result::*;
+fn foo() -> Result<(), i64> {
+    let n = 1;
+    let m = fun_name()?;
+    let h = 1 + m;
+    Ok(())
+}
+
+fn $0fun_name() -> Result<i32, i64> {
+    let k = foo()?;
+    if k == 42 {
+        return Err(1);
+    }
+    let m = k + 1;
+    Ok(m)
+}"##,
+        );
+    }
+
+    #[test]
+    fn try_and_break() {
+        mark::check!(external_control_flow_try_and_bc);
+        check_assist_not_applicable(
+            extract_function,
+            r##"
+enum Option<T> { None, Some(T) }
+use Option::*;
+fn foo() -> Option<()> {
+    loop {
+        let n = Some(1);
+        $0let m = n? + 1;
+        break;
+        let k = 2;
+        let k = k + 1;$0
+        let r = n + k;
+    }
+    Some(())
+}"##,
+        );
+    }
+
+    #[test]
+    fn try_and_return_ok() {
+        mark::check!(external_control_flow_try_and_return_non_err);
+        check_assist_not_applicable(
+            extract_function,
+            r##"
+enum Result<T, E> { Ok(T), Err(E), }
+use Result::*;
+fn foo() -> Result<(), i64> {
+    let n = 1;
+    $0let k = foo()?;
+    if k == 42 {
+        return Ok(1);
+    }
+    let m = k + 1;$0
+    let h = 1 + m;
+    Ok(())
+}"##,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs b/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
new file mode 100644
index 000000000..5c7678b53
--- /dev/null
+++ b/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
@@ -0,0 +1,520 @@
+use std::iter;
+
+use either::Either;
+use hir::{AsName, Module, ModuleDef, Name, Variant};
+use ide_db::{
+    defs::Definition,
+    helpers::{
+        insert_use::{insert_use, ImportScope},
+        mod_path_to_ast,
+    },
+    search::FileReference,
+    RootDatabase,
+};
+use rustc_hash::FxHashSet;
+use syntax::{
+    algo::{find_node_at_offset, SyntaxRewriter},
+    ast::{self, edit::IndentLevel, make, AstNode, NameOwner, VisibilityOwner},
+    SourceFile, SyntaxElement, SyntaxNode, T,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: extract_struct_from_enum_variant
+//
+// Extracts a struct from enum variant.
+//
+// ```
+// enum A { $0One(u32, u32) }
+// ```
+// ->
+// ```
+// struct One(pub u32, pub u32);
+//
+// enum A { One(One) }
+// ```
+pub(crate) fn extract_struct_from_enum_variant(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+) -> Option<()> {
+    let variant = ctx.find_node_at_offset::<ast::Variant>()?;
+    let field_list = extract_field_list_if_applicable(&variant)?;
+
+    let variant_name = variant.name()?;
+    let variant_hir = ctx.sema.to_def(&variant)?;
+    if existing_definition(ctx.db(), &variant_name, &variant_hir) {
+        return None;
+    }
+
+    let enum_ast = variant.parent_enum();
+    let enum_hir = ctx.sema.to_def(&enum_ast)?;
+    let target = variant.syntax().text_range();
+    acc.add(
+        AssistId("extract_struct_from_enum_variant", AssistKind::RefactorRewrite),
+        "Extract struct from enum variant",
+        target,
+        |builder| {
+            let variant_hir_name = variant_hir.name(ctx.db());
+            let enum_module_def = ModuleDef::from(enum_hir);
+            let usages =
+                Definition::ModuleDef(ModuleDef::Variant(variant_hir)).usages(&ctx.sema).all();
+
+            let mut visited_modules_set = FxHashSet::default();
+            let current_module = enum_hir.module(ctx.db());
+            visited_modules_set.insert(current_module);
+            let mut def_rewriter = None;
+            for (file_id, references) in usages {
+                let mut rewriter = SyntaxRewriter::default();
+                let source_file = ctx.sema.parse(file_id);
+                for reference in references {
+                    update_reference(
+                        ctx,
+                        &mut rewriter,
+                        reference,
+                        &source_file,
+                        &enum_module_def,
+                        &variant_hir_name,
+                        &mut visited_modules_set,
+                    );
+                }
+                if file_id == ctx.frange.file_id {
+                    def_rewriter = Some(rewriter);
+                    continue;
+                }
+                builder.edit_file(file_id);
+                builder.rewrite(rewriter);
+            }
+            let mut rewriter = def_rewriter.unwrap_or_default();
+            update_variant(&mut rewriter, &variant);
+            extract_struct_def(
+                &mut rewriter,
+                &enum_ast,
+                variant_name.clone(),
+                &field_list,
+                &variant.parent_enum().syntax().clone().into(),
+                enum_ast.visibility(),
+            );
+            builder.edit_file(ctx.frange.file_id);
+            builder.rewrite(rewriter);
+        },
+    )
+}
+
+fn extract_field_list_if_applicable(
+    variant: &ast::Variant,
+) -> Option<Either<ast::RecordFieldList, ast::TupleFieldList>> {
+    match variant.kind() {
+        ast::StructKind::Record(field_list) if field_list.fields().next().is_some() => {
+            Some(Either::Left(field_list))
+        }
+        ast::StructKind::Tuple(field_list) if field_list.fields().count() > 1 => {
+            Some(Either::Right(field_list))
+        }
+        _ => None,
+    }
+}
+
+fn existing_definition(db: &RootDatabase, variant_name: &ast::Name, variant: &Variant) -> bool {
+    variant
+        .parent_enum(db)
+        .module(db)
+        .scope(db, None)
+        .into_iter()
+        .filter(|(_, def)| match def {
+            // only check type-namespace
+            hir::ScopeDef::ModuleDef(def) => matches!(
+                def,
+                ModuleDef::Module(_)
+                    | ModuleDef::Adt(_)
+                    | ModuleDef::Variant(_)
+                    | ModuleDef::Trait(_)
+                    | ModuleDef::TypeAlias(_)
+                    | ModuleDef::BuiltinType(_)
+            ),
+            _ => false,
+        })
+        .any(|(name, _)| name == variant_name.as_name())
+}
+
+fn insert_import(
+    ctx: &AssistContext,
+    rewriter: &mut SyntaxRewriter,
+    scope_node: &SyntaxNode,
+    module: &Module,
+    enum_module_def: &ModuleDef,
+    variant_hir_name: &Name,
+) -> Option<()> {
+    let db = ctx.db();
+    let mod_path = module.find_use_path_prefixed(
+        db,
+        enum_module_def.clone(),
+        ctx.config.insert_use.prefix_kind,
+    );
+    if let Some(mut mod_path) = mod_path {
+        mod_path.pop_segment();
+        mod_path.push_segment(variant_hir_name.clone());
+        let scope = ImportScope::find_insert_use_container(scope_node, &ctx.sema)?;
+        *rewriter += insert_use(&scope, mod_path_to_ast(&mod_path), ctx.config.insert_use.merge);
+    }
+    Some(())
+}
+
+fn extract_struct_def(
+    rewriter: &mut SyntaxRewriter,
+    enum_: &ast::Enum,
+    variant_name: ast::Name,
+    field_list: &Either<ast::RecordFieldList, ast::TupleFieldList>,
+    start_offset: &SyntaxElement,
+    visibility: Option<ast::Visibility>,
+) -> Option<()> {
+    let pub_vis = Some(make::visibility_pub());
+    let field_list = match field_list {
+        Either::Left(field_list) => {
+            make::record_field_list(field_list.fields().flat_map(|field| {
+                Some(make::record_field(pub_vis.clone(), field.name()?, field.ty()?))
+            }))
+            .into()
+        }
+        Either::Right(field_list) => make::tuple_field_list(
+            field_list
+                .fields()
+                .flat_map(|field| Some(make::tuple_field(pub_vis.clone(), field.ty()?))),
+        )
+        .into(),
+    };
+
+    rewriter.insert_before(
+        start_offset,
+        make::struct_(visibility, variant_name, None, field_list).syntax(),
+    );
+    rewriter.insert_before(start_offset, &make::tokens::blank_line());
+
+    if let indent_level @ 1..=usize::MAX = IndentLevel::from_node(enum_.syntax()).0 as usize {
+        rewriter
+            .insert_before(start_offset, &make::tokens::whitespace(&" ".repeat(4 * indent_level)));
+    }
+    Some(())
+}
+
+fn update_variant(rewriter: &mut SyntaxRewriter, variant: &ast::Variant) -> Option<()> {
+    let name = variant.name()?;
+    let tuple_field = make::tuple_field(None, make::ty(name.text()));
+    let replacement = make::variant(
+        name,
+        Some(ast::FieldList::TupleFieldList(make::tuple_field_list(iter::once(tuple_field)))),
+    );
+    rewriter.replace(variant.syntax(), replacement.syntax());
+    Some(())
+}
+
+fn update_reference(
+    ctx: &AssistContext,
+    rewriter: &mut SyntaxRewriter,
+    reference: FileReference,
+    source_file: &SourceFile,
+    enum_module_def: &ModuleDef,
+    variant_hir_name: &Name,
+    visited_modules_set: &mut FxHashSet<Module>,
+) -> Option<()> {
+    let offset = reference.range.start();
+    let (segment, expr) = if let Some(path_expr) =
+        find_node_at_offset::<ast::PathExpr>(source_file.syntax(), offset)
+    {
+        // tuple variant
+        (path_expr.path()?.segment()?, path_expr.syntax().parent()?)
+    } else if let Some(record_expr) =
+        find_node_at_offset::<ast::RecordExpr>(source_file.syntax(), offset)
+    {
+        // record variant
+        (record_expr.path()?.segment()?, record_expr.syntax().clone())
+    } else {
+        return None;
+    };
+
+    let module = ctx.sema.scope(&expr).module()?;
+    if !visited_modules_set.contains(&module) {
+        if insert_import(ctx, rewriter, &expr, &module, enum_module_def, variant_hir_name).is_some()
+        {
+            visited_modules_set.insert(module);
+        }
+    }
+    rewriter.insert_after(segment.syntax(), &make::token(T!['(']));
+    rewriter.insert_after(segment.syntax(), segment.syntax());
+    rewriter.insert_after(&expr, &make::token(T![')']));
+    Some(())
+}
+
+#[cfg(test)]
+mod tests {
+    use ide_db::helpers::FamousDefs;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn test_extract_struct_several_fields_tuple() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            "enum A { $0One(u32, u32) }",
+            r#"struct One(pub u32, pub u32);
+
+enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_several_fields_named() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            "enum A { $0One { foo: u32, bar: u32 } }",
+            r#"struct One{ pub foo: u32, pub bar: u32 }
+
+enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_one_field_named() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            "enum A { $0One { foo: u32 } }",
+            r#"struct One{ pub foo: u32 }
+
+enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_enum_variant_name_value_namespace() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"const One: () = ();
+enum A { $0One(u32, u32) }"#,
+            r#"const One: () = ();
+struct One(pub u32, pub u32);
+
+enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_pub_visibility() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            "pub enum A { $0One(u32, u32) }",
+            r#"pub struct One(pub u32, pub u32);
+
+pub enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_with_complex_imports() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"mod my_mod {
+    fn another_fn() {
+        let m = my_other_mod::MyEnum::MyField(1, 1);
+    }
+
+    pub mod my_other_mod {
+        fn another_fn() {
+            let m = MyEnum::MyField(1, 1);
+        }
+
+        pub enum MyEnum {
+            $0MyField(u8, u8),
+        }
+    }
+}
+
+fn another_fn() {
+    let m = my_mod::my_other_mod::MyEnum::MyField(1, 1);
+}"#,
+            r#"use my_mod::my_other_mod::MyField;
+
+mod my_mod {
+    use self::my_other_mod::MyField;
+
+    fn another_fn() {
+        let m = my_other_mod::MyEnum::MyField(MyField(1, 1));
+    }
+
+    pub mod my_other_mod {
+        fn another_fn() {
+            let m = MyEnum::MyField(MyField(1, 1));
+        }
+
+        pub struct MyField(pub u8, pub u8);
+
+        pub enum MyEnum {
+            MyField(MyField),
+        }
+    }
+}
+
+fn another_fn() {
+    let m = my_mod::my_other_mod::MyEnum::MyField(MyField(1, 1));
+}"#,
+        );
+    }
+
+    #[test]
+    fn extract_record_fix_references() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"
+enum E {
+    $0V { i: i32, j: i32 }
+}
+
+fn f() {
+    let e = E::V { i: 9, j: 2 };
+}
+"#,
+            r#"
+struct V{ pub i: i32, pub j: i32 }
+
+enum E {
+    V(V)
+}
+
+fn f() {
+    let e = E::V(V { i: 9, j: 2 });
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn test_several_files() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"
+//- /main.rs
+enum E {
+    $0V(i32, i32)
+}
+mod foo;
+
+//- /foo.rs
+use crate::E;
+fn f() {
+    let e = E::V(9, 2);
+}
+"#,
+            r#"
+//- /main.rs
+struct V(pub i32, pub i32);
+
+enum E {
+    V(V)
+}
+mod foo;
+
+//- /foo.rs
+use crate::{E, V};
+fn f() {
+    let e = E::V(V(9, 2));
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn test_several_files_record() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"
+//- /main.rs
+enum E {
+    $0V { i: i32, j: i32 }
+}
+mod foo;
+
+//- /foo.rs
+use crate::E;
+fn f() {
+    let e = E::V { i: 9, j: 2 };
+}
+"#,
+            r#"
+//- /main.rs
+struct V{ pub i: i32, pub j: i32 }
+
+enum E {
+    V(V)
+}
+mod foo;
+
+//- /foo.rs
+use crate::{E, V};
+fn f() {
+    let e = E::V(V { i: 9, j: 2 });
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn test_extract_struct_record_nested_call_exp() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"
+enum A { $0One { a: u32, b: u32 } }
+
+struct B(A);
+
+fn foo() {
+    let _ = B(A::One { a: 1, b: 2 });
+}
+"#,
+            r#"
+struct One{ pub a: u32, pub b: u32 }
+
+enum A { One(One) }
+
+struct B(A);
+
+fn foo() {
+    let _ = B(A::One(One { a: 1, b: 2 }));
+}
+"#,
+        );
+    }
+
+    fn check_not_applicable(ra_fixture: &str) {
+        let fixture =
+            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
+        check_assist_not_applicable(extract_struct_from_enum_variant, &fixture)
+    }
+
+    #[test]
+    fn test_extract_enum_not_applicable_for_element_with_no_fields() {
+        check_not_applicable("enum A { $0One }");
+    }
+
+    #[test]
+    fn test_extract_enum_not_applicable_if_struct_exists() {
+        check_not_applicable(
+            r#"struct One;
+        enum A { $0One(u8, u32) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_not_applicable_one_field() {
+        check_not_applicable(r"enum A { $0One(u32) }");
+    }
+
+    #[test]
+    fn test_extract_not_applicable_no_field_tuple() {
+        check_not_applicable(r"enum A { $0None() }");
+    }
+
+    #[test]
+    fn test_extract_not_applicable_no_field_named() {
+        check_not_applicable(r"enum A { $0None {} }");
+    }
+}
diff --git a/crates/ide_assists/src/handlers/extract_variable.rs b/crates/ide_assists/src/handlers/extract_variable.rs
new file mode 100644
index 000000000..98f3dc6ca
--- /dev/null
+++ b/crates/ide_assists/src/handlers/extract_variable.rs
@@ -0,0 +1,588 @@
+use stdx::format_to;
+use syntax::{
+    ast::{self, AstNode},
+    SyntaxKind::{
+        BLOCK_EXPR, BREAK_EXPR, CLOSURE_EXPR, COMMENT, LOOP_EXPR, MATCH_ARM, PATH_EXPR, RETURN_EXPR,
+    },
+    SyntaxNode,
+};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: extract_variable
+//
+// Extracts subexpression into a variable.
+//
+// ```
+// fn main() {
+//     $0(1 + 2)$0 * 4;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     let $0var_name = (1 + 2);
+//     var_name * 4;
+// }
+// ```
+pub(crate) fn extract_variable(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    if ctx.frange.range.is_empty() {
+        return None;
+    }
+    let node = ctx.covering_element();
+    if node.kind() == COMMENT {
+        mark::hit!(extract_var_in_comment_is_not_applicable);
+        return None;
+    }
+    let to_extract = node.ancestors().find_map(valid_target_expr)?;
+    let anchor = Anchor::from(&to_extract)?;
+    let indent = anchor.syntax().prev_sibling_or_token()?.as_token()?.clone();
+    let target = to_extract.syntax().text_range();
+    acc.add(
+        AssistId("extract_variable", AssistKind::RefactorExtract),
+        "Extract into variable",
+        target,
+        move |edit| {
+            let field_shorthand =
+                match to_extract.syntax().parent().and_then(ast::RecordExprField::cast) {
+                    Some(field) => field.name_ref(),
+                    None => None,
+                };
+
+            let mut buf = String::new();
+
+            let var_name = match &field_shorthand {
+                Some(it) => it.to_string(),
+                None => "var_name".to_string(),
+            };
+            let expr_range = match &field_shorthand {
+                Some(it) => it.syntax().text_range().cover(to_extract.syntax().text_range()),
+                None => to_extract.syntax().text_range(),
+            };
+
+            if let Anchor::WrapInBlock(_) = anchor {
+                format_to!(buf, "{{ let {} = ", var_name);
+            } else {
+                format_to!(buf, "let {} = ", var_name);
+            };
+            format_to!(buf, "{}", to_extract.syntax());
+
+            if let Anchor::Replace(stmt) = anchor {
+                mark::hit!(test_extract_var_expr_stmt);
+                if stmt.semicolon_token().is_none() {
+                    buf.push_str(";");
+                }
+                match ctx.config.snippet_cap {
+                    Some(cap) => {
+                        let snip = buf
+                            .replace(&format!("let {}", var_name), &format!("let $0{}", var_name));
+                        edit.replace_snippet(cap, expr_range, snip)
+                    }
+                    None => edit.replace(expr_range, buf),
+                }
+                return;
+            }
+
+            buf.push_str(";");
+
+            // We want to maintain the indent level,
+            // but we do not want to duplicate possible
+            // extra newlines in the indent block
+            let text = indent.text();
+            if text.starts_with('\n') {
+                buf.push('\n');
+                buf.push_str(text.trim_start_matches('\n'));
+            } else {
+                buf.push_str(text);
+            }
+
+            edit.replace(expr_range, var_name.clone());
+            let offset = anchor.syntax().text_range().start();
+            match ctx.config.snippet_cap {
+                Some(cap) => {
+                    let snip =
+                        buf.replace(&format!("let {}", var_name), &format!("let $0{}", var_name));
+                    edit.insert_snippet(cap, offset, snip)
+                }
+                None => edit.insert(offset, buf),
+            }
+
+            if let Anchor::WrapInBlock(_) = anchor {
+                edit.insert(anchor.syntax().text_range().end(), " }");
+            }
+        },
+    )
+}
+
+/// Check whether the node is a valid expression which can be extracted to a variable.
+/// In general that's true for any expression, but in some cases that would produce invalid code.
+fn valid_target_expr(node: SyntaxNode) -> Option<ast::Expr> {
+    match node.kind() {
+        PATH_EXPR | LOOP_EXPR => None,
+        BREAK_EXPR => ast::BreakExpr::cast(node).and_then(|e| e.expr()),
+        RETURN_EXPR => ast::ReturnExpr::cast(node).and_then(|e| e.expr()),
+        BLOCK_EXPR => {
+            ast::BlockExpr::cast(node).filter(|it| it.is_standalone()).map(ast::Expr::from)
+        }
+        _ => ast::Expr::cast(node),
+    }
+}
+
+enum Anchor {
+    Before(SyntaxNode),
+    Replace(ast::ExprStmt),
+    WrapInBlock(SyntaxNode),
+}
+
+impl Anchor {
+    fn from(to_extract: &ast::Expr) -> Option<Anchor> {
+        to_extract.syntax().ancestors().find_map(|node| {
+            if let Some(expr) =
+                node.parent().and_then(ast::BlockExpr::cast).and_then(|it| it.tail_expr())
+            {
+                if expr.syntax() == &node {
+                    mark::hit!(test_extract_var_last_expr);
+                    return Some(Anchor::Before(node));
+                }
+            }
+
+            if let Some(parent) = node.parent() {
+                if parent.kind() == MATCH_ARM || parent.kind() == CLOSURE_EXPR {
+                    return Some(Anchor::WrapInBlock(node));
+                }
+            }
+
+            if let Some(stmt) = ast::Stmt::cast(node.clone()) {
+                if let ast::Stmt::ExprStmt(stmt) = stmt {
+                    if stmt.expr().as_ref() == Some(to_extract) {
+                        return Some(Anchor::Replace(stmt));
+                    }
+                }
+                return Some(Anchor::Before(node));
+            }
+            None
+        })
+    }
+
+    fn syntax(&self) -> &SyntaxNode {
+        match self {
+            Anchor::Before(it) | Anchor::WrapInBlock(it) => it,
+            Anchor::Replace(stmt) => stmt.syntax(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn test_extract_var_simple() {
+        check_assist(
+            extract_variable,
+            r#"
+fn foo() {
+    foo($01 + 1$0);
+}"#,
+            r#"
+fn foo() {
+    let $0var_name = 1 + 1;
+    foo(var_name);
+}"#,
+        );
+    }
+
+    #[test]
+    fn extract_var_in_comment_is_not_applicable() {
+        mark::check!(extract_var_in_comment_is_not_applicable);
+        check_assist_not_applicable(extract_variable, "fn main() { 1 + /* $0comment$0 */ 1; }");
+    }
+
+    #[test]
+    fn test_extract_var_expr_stmt() {
+        mark::check!(test_extract_var_expr_stmt);
+        check_assist(
+            extract_variable,
+            r#"
+fn foo() {
+    $01 + 1$0;
+}"#,
+            r#"
+fn foo() {
+    let $0var_name = 1 + 1;
+}"#,
+        );
+        check_assist(
+            extract_variable,
+            "
+fn foo() {
+    $0{ let x = 0; x }$0
+    something_else();
+}",
+            "
+fn foo() {
+    let $0var_name = { let x = 0; x };
+    something_else();
+}",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_part_of_expr_stmt() {
+        check_assist(
+            extract_variable,
+            "
+fn foo() {
+    $01$0 + 1;
+}",
+            "
+fn foo() {
+    let $0var_name = 1;
+    var_name + 1;
+}",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_last_expr() {
+        mark::check!(test_extract_var_last_expr);
+        check_assist(
+            extract_variable,
+            r#"
+fn foo() {
+    bar($01 + 1$0)
+}
+"#,
+            r#"
+fn foo() {
+    let $0var_name = 1 + 1;
+    bar(var_name)
+}
+"#,
+        );
+        check_assist(
+            extract_variable,
+            r#"
+fn foo() {
+    $0bar(1 + 1)$0
+}
+"#,
+            r#"
+fn foo() {
+    let $0var_name = bar(1 + 1);
+    var_name
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn test_extract_var_in_match_arm_no_block() {
+        check_assist(
+            extract_variable,
+            "
+fn main() {
+    let x = true;
+    let tuple = match x {
+        true => ($02 + 2$0, true)
+        _ => (0, false)
+    };
+}
+",
+            "
+fn main() {
+    let x = true;
+    let tuple = match x {
+        true => { let $0var_name = 2 + 2; (var_name, true) }
+        _ => (0, false)
+    };
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_in_match_arm_with_block() {
+        check_assist(
+            extract_variable,
+            "
+fn main() {
+    let x = true;
+    let tuple = match x {
+        true => {
+            let y = 1;
+            ($02 + y$0, true)
+        }
+        _ => (0, false)
+    };
+}
+",
+            "
+fn main() {
+    let x = true;
+    let tuple = match x {
+        true => {
+            let y = 1;
+            let $0var_name = 2 + y;
+            (var_name, true)
+        }
+        _ => (0, false)
+    };
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_in_closure_no_block() {
+        check_assist(
+            extract_variable,
+            "
+fn main() {
+    let lambda = |x: u32| $0x * 2$0;
+}
+",
+            "
+fn main() {
+    let lambda = |x: u32| { let $0var_name = x * 2; var_name };
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_in_closure_with_block() {
+        check_assist(
+            extract_variable,
+            "
+fn main() {
+    let lambda = |x: u32| { $0x * 2$0 };
+}
+",
+            "
+fn main() {
+    let lambda = |x: u32| { let $0var_name = x * 2; var_name };
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_path_simple() {
+        check_assist(
+            extract_variable,
+            "
+fn main() {
+    let o = $0Some(true)$0;
+}
+",
+            "
+fn main() {
+    let $0var_name = Some(true);
+    let o = var_name;
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_path_method() {
+        check_assist(
+            extract_variable,
+            "
+fn main() {
+    let v = $0bar.foo()$0;
+}
+",
+            "
+fn main() {
+    let $0var_name = bar.foo();
+    let v = var_name;
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_return() {
+        check_assist(
+            extract_variable,
+            "
+fn foo() -> u32 {
+    $0return 2 + 2$0;
+}
+",
+            "
+fn foo() -> u32 {
+    let $0var_name = 2 + 2;
+    return var_name;
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_does_not_add_extra_whitespace() {
+        check_assist(
+            extract_variable,
+            "
+fn foo() -> u32 {
+
+
+    $0return 2 + 2$0;
+}
+",
+            "
+fn foo() -> u32 {
+
+
+    let $0var_name = 2 + 2;
+    return var_name;
+}
+",
+        );
+
+        check_assist(
+            extract_variable,
+            "
+fn foo() -> u32 {
+
+        $0return 2 + 2$0;
+}
+",
+            "
+fn foo() -> u32 {
+
+        let $0var_name = 2 + 2;
+        return var_name;
+}
+",
+        );
+
+        check_assist(
+            extract_variable,
+            "
+fn foo() -> u32 {
+    let foo = 1;
+
+    // bar
+
+
+    $0return 2 + 2$0;
+}
+",
+            "
+fn foo() -> u32 {
+    let foo = 1;
+
+    // bar
+
+
+    let $0var_name = 2 + 2;
+    return var_name;
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_break() {
+        check_assist(
+            extract_variable,
+            "
+fn main() {
+    let result = loop {
+        $0break 2 + 2$0;
+    };
+}
+",
+            "
+fn main() {
+    let result = loop {
+        let $0var_name = 2 + 2;
+        break var_name;
+    };
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_extract_var_for_cast() {
+        check_assist(
+            extract_variable,
+            "
+fn main() {
+    let v = $00f32 as u32$0;
+}
+",
+            "
+fn main() {
+    let $0var_name = 0f32 as u32;
+    let v = var_name;
+}
+",
+        );
+    }
+
+    #[test]
+    fn extract_var_field_shorthand() {
+        check_assist(
+            extract_variable,
+            r#"
+struct S {
+    foo: i32
+}
+
+fn main() {
+    S { foo: $01 + 1$0 }
+}
+"#,
+            r#"
+struct S {
+    foo: i32
+}
+
+fn main() {
+    let $0foo = 1 + 1;
+    S { foo }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn test_extract_var_for_return_not_applicable() {
+        check_assist_not_applicable(extract_variable, "fn foo() { $0return$0; } ");
+    }
+
+    #[test]
+    fn test_extract_var_for_break_not_applicable() {
+        check_assist_not_applicable(extract_variable, "fn main() { loop { $0break$0; }; }");
+    }
+
+    // FIXME: This is not quite correct, but good enough(tm) for the sorting heuristic
+    #[test]
+    fn extract_var_target() {
+        check_assist_target(extract_variable, "fn foo() -> u32 { $0return 2 + 2$0; }", "2 + 2");
+
+        check_assist_target(
+            extract_variable,
+            "
+fn main() {
+    let x = true;
+    let tuple = match x {
+        true => ($02 + 2$0, true)
+        _ => (0, false)
+    };
+}
+",
+            "2 + 2",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/fill_match_arms.rs b/crates/ide_assists/src/handlers/fill_match_arms.rs
new file mode 100644
index 000000000..7086e47d2
--- /dev/null
+++ b/crates/ide_assists/src/handlers/fill_match_arms.rs
@@ -0,0 +1,787 @@
+use std::iter;
+
+use hir::{Adt, HasSource, ModuleDef, Semantics};
+use ide_db::helpers::{mod_path_to_ast, FamousDefs};
+use ide_db::RootDatabase;
+use itertools::Itertools;
+use syntax::ast::{self, make, AstNode, MatchArm, NameOwner, Pat};
+use test_utils::mark;
+
+use crate::{
+    utils::{does_pat_match_variant, render_snippet, Cursor},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: fill_match_arms
+//
+// Adds missing clauses to a `match` expression.
+//
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         $0
+//     }
+// }
+// ```
+// ->
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         $0Action::Move { distance } => {}
+//         Action::Stop => {}
+//     }
+// }
+// ```
+pub(crate) fn fill_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let match_expr = ctx.find_node_at_offset_with_descend::<ast::MatchExpr>()?;
+    let match_arm_list = match_expr.match_arm_list()?;
+
+    let expr = match_expr.expr()?;
+
+    let mut arms: Vec<MatchArm> = match_arm_list.arms().collect();
+    if arms.len() == 1 {
+        if let Some(Pat::WildcardPat(..)) = arms[0].pat() {
+            arms.clear();
+        }
+    }
+
+    let module = ctx.sema.scope(expr.syntax()).module()?;
+
+    let missing_arms: Vec<MatchArm> = if let Some(enum_def) = resolve_enum_def(&ctx.sema, &expr) {
+        let variants = enum_def.variants(ctx.db());
+
+        let mut variants = variants
+            .into_iter()
+            .filter_map(|variant| build_pat(ctx.db(), module, variant))
+            .filter(|variant_pat| is_variant_missing(&mut arms, variant_pat))
+            .map(|pat| make::match_arm(iter::once(pat), make::expr_empty_block()))
+            .collect::<Vec<_>>();
+        if Some(enum_def) == FamousDefs(&ctx.sema, Some(module.krate())).core_option_Option() {
+            // Match `Some` variant first.
+            mark::hit!(option_order);
+            variants.reverse()
+        }
+        variants
+    } else if let Some(enum_defs) = resolve_tuple_of_enum_def(&ctx.sema, &expr) {
+        // Partial fill not currently supported for tuple of enums.
+        if !arms.is_empty() {
+            return None;
+        }
+
+        // We do not currently support filling match arms for a tuple
+        // containing a single enum.
+        if enum_defs.len() < 2 {
+            return None;
+        }
+
+        // When calculating the match arms for a tuple of enums, we want
+        // to create a match arm for each possible combination of enum
+        // values. The `multi_cartesian_product` method transforms
+        // Vec<Vec<EnumVariant>> into Vec<(EnumVariant, .., EnumVariant)>
+        // where each tuple represents a proposed match arm.
+        enum_defs
+            .into_iter()
+            .map(|enum_def| enum_def.variants(ctx.db()))
+            .multi_cartesian_product()
+            .map(|variants| {
+                let patterns =
+                    variants.into_iter().filter_map(|variant| build_pat(ctx.db(), module, variant));
+                ast::Pat::from(make::tuple_pat(patterns))
+            })
+            .filter(|variant_pat| is_variant_missing(&mut arms, variant_pat))
+            .map(|pat| make::match_arm(iter::once(pat), make::expr_empty_block()))
+            .collect()
+    } else {
+        return None;
+    };
+
+    if missing_arms.is_empty() {
+        return None;
+    }
+
+    let target = ctx.sema.original_range(match_expr.syntax()).range;
+    acc.add(
+        AssistId("fill_match_arms", AssistKind::QuickFix),
+        "Fill match arms",
+        target,
+        |builder| {
+            let new_arm_list = match_arm_list.remove_placeholder();
+            let n_old_arms = new_arm_list.arms().count();
+            let new_arm_list = new_arm_list.append_arms(missing_arms);
+            let first_new_arm = new_arm_list.arms().nth(n_old_arms);
+            let old_range = ctx.sema.original_range(match_arm_list.syntax()).range;
+            match (first_new_arm, ctx.config.snippet_cap) {
+                (Some(first_new_arm), Some(cap)) => {
+                    let extend_lifetime;
+                    let cursor =
+                        match first_new_arm.syntax().descendants().find_map(ast::WildcardPat::cast)
+                        {
+                            Some(it) => {
+                                extend_lifetime = it.syntax().clone();
+                                Cursor::Replace(&extend_lifetime)
+                            }
+                            None => Cursor::Before(first_new_arm.syntax()),
+                        };
+                    let snippet = render_snippet(cap, new_arm_list.syntax(), cursor);
+                    builder.replace_snippet(cap, old_range, snippet);
+                }
+                _ => builder.replace(old_range, new_arm_list.to_string()),
+            }
+        },
+    )
+}
+
+fn is_variant_missing(existing_arms: &mut Vec<MatchArm>, var: &Pat) -> bool {
+    existing_arms.iter().filter_map(|arm| arm.pat()).all(|pat| {
+        // Special casee OrPat as separate top-level pats
+        let top_level_pats: Vec<Pat> = match pat {
+            Pat::OrPat(pats) => pats.pats().collect::<Vec<_>>(),
+            _ => vec![pat],
+        };
+
+        !top_level_pats.iter().any(|pat| does_pat_match_variant(pat, var))
+    })
+}
+
+fn resolve_enum_def(sema: &Semantics<RootDatabase>, expr: &ast::Expr) -> Option<hir::Enum> {
+    sema.type_of_expr(&expr)?.autoderef(sema.db).find_map(|ty| match ty.as_adt() {
+        Some(Adt::Enum(e)) => Some(e),
+        _ => None,
+    })
+}
+
+fn resolve_tuple_of_enum_def(
+    sema: &Semantics<RootDatabase>,
+    expr: &ast::Expr,
+) -> Option<Vec<hir::Enum>> {
+    sema.type_of_expr(&expr)?
+        .tuple_fields(sema.db)
+        .iter()
+        .map(|ty| {
+            ty.autoderef(sema.db).find_map(|ty| match ty.as_adt() {
+                Some(Adt::Enum(e)) => Some(e),
+                // For now we only handle expansion for a tuple of enums. Here
+                // we map non-enum items to None and rely on `collect` to
+                // convert Vec<Option<hir::Enum>> into Option<Vec<hir::Enum>>.
+                _ => None,
+            })
+        })
+        .collect()
+}
+
+fn build_pat(db: &RootDatabase, module: hir::Module, var: hir::Variant) -> Option<ast::Pat> {
+    let path = mod_path_to_ast(&module.find_use_path(db, ModuleDef::from(var))?);
+
+    // FIXME: use HIR for this; it doesn't currently expose struct vs. tuple vs. unit variants though
+    let pat: ast::Pat = match var.source(db)?.value.kind() {
+        ast::StructKind::Tuple(field_list) => {
+            let pats = iter::repeat(make::wildcard_pat().into()).take(field_list.fields().count());
+            make::tuple_struct_pat(path, pats).into()
+        }
+        ast::StructKind::Record(field_list) => {
+            let pats = field_list.fields().map(|f| make::ident_pat(f.name().unwrap()).into());
+            make::record_pat(path, pats).into()
+        }
+        ast::StructKind::Unit => make::path_pat(path),
+    };
+
+    Some(pat)
+}
+
+#[cfg(test)]
+mod tests {
+    use ide_db::helpers::FamousDefs;
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::fill_match_arms;
+
+    #[test]
+    fn all_match_arms_provided() {
+        check_assist_not_applicable(
+            fill_match_arms,
+            r#"
+            enum A {
+                As,
+                Bs{x:i32, y:Option<i32>},
+                Cs(i32, Option<i32>),
+            }
+            fn main() {
+                match A::As$0 {
+                    A::As,
+                    A::Bs{x,y:Some(_)} => {}
+                    A::Cs(_, Some(_)) => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn tuple_of_non_enum() {
+        // for now this case is not handled, although it potentially could be
+        // in the future
+        check_assist_not_applicable(
+            fill_match_arms,
+            r#"
+            fn main() {
+                match (0, false)$0 {
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn partial_fill_record_tuple() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A {
+                As,
+                Bs { x: i32, y: Option<i32> },
+                Cs(i32, Option<i32>),
+            }
+            fn main() {
+                match A::As$0 {
+                    A::Bs { x, y: Some(_) } => {}
+                    A::Cs(_, Some(_)) => {}
+                }
+            }
+            "#,
+            r#"
+            enum A {
+                As,
+                Bs { x: i32, y: Option<i32> },
+                Cs(i32, Option<i32>),
+            }
+            fn main() {
+                match A::As {
+                    A::Bs { x, y: Some(_) } => {}
+                    A::Cs(_, Some(_)) => {}
+                    $0A::As => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn partial_fill_option() {
+        check_assist(
+            fill_match_arms,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn main() {
+    match None$0 {
+        None => {}
+    }
+}
+            "#,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn main() {
+    match None {
+        None => {}
+        Some(${0:_}) => {}
+    }
+}
+            "#,
+        );
+    }
+
+    #[test]
+    fn partial_fill_or_pat() {
+        check_assist(
+            fill_match_arms,
+            r#"
+enum A { As, Bs, Cs(Option<i32>) }
+fn main() {
+    match A::As$0 {
+        A::Cs(_) | A::Bs => {}
+    }
+}
+"#,
+            r#"
+enum A { As, Bs, Cs(Option<i32>) }
+fn main() {
+    match A::As {
+        A::Cs(_) | A::Bs => {}
+        $0A::As => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn partial_fill() {
+        check_assist(
+            fill_match_arms,
+            r#"
+enum A { As, Bs, Cs, Ds(String), Es(B) }
+enum B { Xs, Ys }
+fn main() {
+    match A::As$0 {
+        A::Bs if 0 < 1 => {}
+        A::Ds(_value) => { let x = 1; }
+        A::Es(B::Xs) => (),
+    }
+}
+"#,
+            r#"
+enum A { As, Bs, Cs, Ds(String), Es(B) }
+enum B { Xs, Ys }
+fn main() {
+    match A::As {
+        A::Bs if 0 < 1 => {}
+        A::Ds(_value) => { let x = 1; }
+        A::Es(B::Xs) => (),
+        $0A::As => {}
+        A::Cs => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn partial_fill_bind_pat() {
+        check_assist(
+            fill_match_arms,
+            r#"
+enum A { As, Bs, Cs(Option<i32>) }
+fn main() {
+    match A::As$0 {
+        A::As(_) => {}
+        a @ A::Bs(_) => {}
+    }
+}
+"#,
+            r#"
+enum A { As, Bs, Cs(Option<i32>) }
+fn main() {
+    match A::As {
+        A::As(_) => {}
+        a @ A::Bs(_) => {}
+        A::Cs(${0:_}) => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_empty_body() {
+        check_assist(
+            fill_match_arms,
+            r#"
+enum A { As, Bs, Cs(String), Ds(String, String), Es { x: usize, y: usize } }
+
+fn main() {
+    let a = A::As;
+    match a$0 {}
+}
+"#,
+            r#"
+enum A { As, Bs, Cs(String), Ds(String, String), Es { x: usize, y: usize } }
+
+fn main() {
+    let a = A::As;
+    match a {
+        $0A::As => {}
+        A::Bs => {}
+        A::Cs(_) => {}
+        A::Ds(_, _) => {}
+        A::Es { x, y } => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_tuple_of_enum() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A { One, Two }
+            enum B { One, Two }
+
+            fn main() {
+                let a = A::One;
+                let b = B::One;
+                match (a$0, b) {}
+            }
+            "#,
+            r#"
+            enum A { One, Two }
+            enum B { One, Two }
+
+            fn main() {
+                let a = A::One;
+                let b = B::One;
+                match (a, b) {
+                    $0(A::One, B::One) => {}
+                    (A::One, B::Two) => {}
+                    (A::Two, B::One) => {}
+                    (A::Two, B::Two) => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_tuple_of_enum_ref() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A { One, Two }
+            enum B { One, Two }
+
+            fn main() {
+                let a = A::One;
+                let b = B::One;
+                match (&a$0, &b) {}
+            }
+            "#,
+            r#"
+            enum A { One, Two }
+            enum B { One, Two }
+
+            fn main() {
+                let a = A::One;
+                let b = B::One;
+                match (&a, &b) {
+                    $0(A::One, B::One) => {}
+                    (A::One, B::Two) => {}
+                    (A::Two, B::One) => {}
+                    (A::Two, B::Two) => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_tuple_of_enum_partial() {
+        check_assist_not_applicable(
+            fill_match_arms,
+            r#"
+            enum A { One, Two }
+            enum B { One, Two }
+
+            fn main() {
+                let a = A::One;
+                let b = B::One;
+                match (a$0, b) {
+                    (A::Two, B::One) => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_tuple_of_enum_not_applicable() {
+        check_assist_not_applicable(
+            fill_match_arms,
+            r#"
+            enum A { One, Two }
+            enum B { One, Two }
+
+            fn main() {
+                let a = A::One;
+                let b = B::One;
+                match (a$0, b) {
+                    (A::Two, B::One) => {}
+                    (A::One, B::One) => {}
+                    (A::One, B::Two) => {}
+                    (A::Two, B::Two) => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_single_element_tuple_of_enum() {
+        // For now we don't hande the case of a single element tuple, but
+        // we could handle this in the future if `make::tuple_pat` allowed
+        // creating a tuple with a single pattern.
+        check_assist_not_applicable(
+            fill_match_arms,
+            r#"
+            enum A { One, Two }
+
+            fn main() {
+                let a = A::One;
+                match (a$0, ) {
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_fill_match_arm_refs() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A { As }
+
+            fn foo(a: &A) {
+                match a$0 {
+                }
+            }
+            "#,
+            r#"
+            enum A { As }
+
+            fn foo(a: &A) {
+                match a {
+                    $0A::As => {}
+                }
+            }
+            "#,
+        );
+
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A {
+                Es { x: usize, y: usize }
+            }
+
+            fn foo(a: &mut A) {
+                match a$0 {
+                }
+            }
+            "#,
+            r#"
+            enum A {
+                Es { x: usize, y: usize }
+            }
+
+            fn foo(a: &mut A) {
+                match a {
+                    $0A::Es { x, y } => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_target() {
+        check_assist_target(
+            fill_match_arms,
+            r#"
+            enum E { X, Y }
+
+            fn main() {
+                match E::X$0 {}
+            }
+            "#,
+            "match E::X {}",
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_trivial_arm() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum E { X, Y }
+
+            fn main() {
+                match E::X {
+                    $0_ => {}
+                }
+            }
+            "#,
+            r#"
+            enum E { X, Y }
+
+            fn main() {
+                match E::X {
+                    $0E::X => {}
+                    E::Y => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_qualifies_path() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            mod foo { pub enum E { X, Y } }
+            use foo::E::X;
+
+            fn main() {
+                match X {
+                    $0
+                }
+            }
+            "#,
+            r#"
+            mod foo { pub enum E { X, Y } }
+            use foo::E::X;
+
+            fn main() {
+                match X {
+                    $0X => {}
+                    foo::E::Y => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_preserves_comments() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A { One, Two }
+            fn foo(a: A) {
+                match a {
+                    // foo bar baz$0
+                    A::One => {}
+                    // This is where the rest should be
+                }
+            }
+            "#,
+            r#"
+            enum A { One, Two }
+            fn foo(a: A) {
+                match a {
+                    // foo bar baz
+                    A::One => {}
+                    // This is where the rest should be
+                    $0A::Two => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_preserves_comments_empty() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A { One, Two }
+            fn foo(a: A) {
+                match a {
+                    // foo bar baz$0
+                }
+            }
+            "#,
+            r#"
+            enum A { One, Two }
+            fn foo(a: A) {
+                match a {
+                    // foo bar baz
+                    $0A::One => {}
+                    A::Two => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn fill_match_arms_placeholder() {
+        check_assist(
+            fill_match_arms,
+            r#"
+            enum A { One, Two, }
+            fn foo(a: A) {
+                match a$0 {
+                    _ => (),
+                }
+            }
+            "#,
+            r#"
+            enum A { One, Two, }
+            fn foo(a: A) {
+                match a {
+                    $0A::One => {}
+                    A::Two => {}
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn option_order() {
+        mark::check!(option_order);
+        let before = r#"
+fn foo(opt: Option<i32>) {
+    match opt$0 {
+    }
+}
+"#;
+        let before = &format!("//- /main.rs crate:main deps:core{}{}", before, FamousDefs::FIXTURE);
+
+        check_assist(
+            fill_match_arms,
+            before,
+            r#"
+fn foo(opt: Option<i32>) {
+    match opt {
+        Some(${0:_}) => {}
+        None => {}
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn works_inside_macro_call() {
+        check_assist(
+            fill_match_arms,
+            r#"
+macro_rules! m { ($expr:expr) => {$expr}}
+enum Test {
+    A,
+    B,
+    C,
+}
+
+fn foo(t: Test) {
+    m!(match t$0 {});
+}"#,
+            r#"macro_rules! m { ($expr:expr) => {$expr}}
+enum Test {
+    A,
+    B,
+    C,
+}
+
+fn foo(t: Test) {
+    m!(match t {
+    $0Test::A => {}
+    Test::B => {}
+    Test::C => {}
+});
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/fix_visibility.rs b/crates/ide_assists/src/handlers/fix_visibility.rs
new file mode 100644
index 000000000..6c7824e55
--- /dev/null
+++ b/crates/ide_assists/src/handlers/fix_visibility.rs
@@ -0,0 +1,607 @@
+use hir::{db::HirDatabase, HasSource, HasVisibility, PathResolution};
+use ide_db::base_db::FileId;
+use syntax::{
+    ast::{self, VisibilityOwner},
+    AstNode, TextRange, TextSize,
+};
+
+use crate::{utils::vis_offset, AssistContext, AssistId, AssistKind, Assists};
+
+// FIXME: this really should be a fix for diagnostic, rather than an assist.
+
+// Assist: fix_visibility
+//
+// Makes inaccessible item public.
+//
+// ```
+// mod m {
+//     fn frobnicate() {}
+// }
+// fn main() {
+//     m::frobnicate$0() {}
+// }
+// ```
+// ->
+// ```
+// mod m {
+//     $0pub(crate) fn frobnicate() {}
+// }
+// fn main() {
+//     m::frobnicate() {}
+// }
+// ```
+pub(crate) fn fix_visibility(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    add_vis_to_referenced_module_def(acc, ctx)
+        .or_else(|| add_vis_to_referenced_record_field(acc, ctx))
+}
+
+fn add_vis_to_referenced_module_def(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let path: ast::Path = ctx.find_node_at_offset()?;
+    let path_res = ctx.sema.resolve_path(&path)?;
+    let def = match path_res {
+        PathResolution::Def(def) => def,
+        _ => return None,
+    };
+
+    let current_module = ctx.sema.scope(&path.syntax()).module()?;
+    let target_module = def.module(ctx.db())?;
+
+    let vis = target_module.visibility_of(ctx.db(), &def)?;
+    if vis.is_visible_from(ctx.db(), current_module.into()) {
+        return None;
+    };
+
+    let (offset, current_visibility, target, target_file, target_name) =
+        target_data_for_def(ctx.db(), def)?;
+
+    let missing_visibility =
+        if current_module.krate() == target_module.krate() { "pub(crate)" } else { "pub" };
+
+    let assist_label = match target_name {
+        None => format!("Change visibility to {}", missing_visibility),
+        Some(name) => format!("Change visibility of {} to {}", name, missing_visibility),
+    };
+
+    acc.add(AssistId("fix_visibility", AssistKind::QuickFix), assist_label, target, |builder| {
+        builder.edit_file(target_file);
+        match ctx.config.snippet_cap {
+            Some(cap) => match current_visibility {
+                Some(current_visibility) => builder.replace_snippet(
+                    cap,
+                    current_visibility.syntax().text_range(),
+                    format!("$0{}", missing_visibility),
+                ),
+                None => builder.insert_snippet(cap, offset, format!("$0{} ", missing_visibility)),
+            },
+            None => match current_visibility {
+                Some(current_visibility) => {
+                    builder.replace(current_visibility.syntax().text_range(), missing_visibility)
+                }
+                None => builder.insert(offset, format!("{} ", missing_visibility)),
+            },
+        }
+    })
+}
+
+fn add_vis_to_referenced_record_field(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let record_field: ast::RecordExprField = ctx.find_node_at_offset()?;
+    let (record_field_def, _) = ctx.sema.resolve_record_field(&record_field)?;
+
+    let current_module = ctx.sema.scope(record_field.syntax()).module()?;
+    let visibility = record_field_def.visibility(ctx.db());
+    if visibility.is_visible_from(ctx.db(), current_module.into()) {
+        return None;
+    }
+
+    let parent = record_field_def.parent_def(ctx.db());
+    let parent_name = parent.name(ctx.db());
+    let target_module = parent.module(ctx.db());
+
+    let in_file_source = record_field_def.source(ctx.db())?;
+    let (offset, current_visibility, target) = match in_file_source.value {
+        hir::FieldSource::Named(it) => {
+            let s = it.syntax();
+            (vis_offset(s), it.visibility(), s.text_range())
+        }
+        hir::FieldSource::Pos(it) => {
+            let s = it.syntax();
+            (vis_offset(s), it.visibility(), s.text_range())
+        }
+    };
+
+    let missing_visibility =
+        if current_module.krate() == target_module.krate() { "pub(crate)" } else { "pub" };
+    let target_file = in_file_source.file_id.original_file(ctx.db());
+
+    let target_name = record_field_def.name(ctx.db());
+    let assist_label =
+        format!("Change visibility of {}.{} to {}", parent_name, target_name, missing_visibility);
+
+    acc.add(AssistId("fix_visibility", AssistKind::QuickFix), assist_label, target, |builder| {
+        builder.edit_file(target_file);
+        match ctx.config.snippet_cap {
+            Some(cap) => match current_visibility {
+                Some(current_visibility) => builder.replace_snippet(
+                    cap,
+                    current_visibility.syntax().text_range(),
+                    format!("$0{}", missing_visibility),
+                ),
+                None => builder.insert_snippet(cap, offset, format!("$0{} ", missing_visibility)),
+            },
+            None => match current_visibility {
+                Some(current_visibility) => {
+                    builder.replace(current_visibility.syntax().text_range(), missing_visibility)
+                }
+                None => builder.insert(offset, format!("{} ", missing_visibility)),
+            },
+        }
+    })
+}
+
+fn target_data_for_def(
+    db: &dyn HirDatabase,
+    def: hir::ModuleDef,
+) -> Option<(TextSize, Option<ast::Visibility>, TextRange, FileId, Option<hir::Name>)> {
+    fn offset_target_and_file_id<S, Ast>(
+        db: &dyn HirDatabase,
+        x: S,
+    ) -> Option<(TextSize, Option<ast::Visibility>, TextRange, FileId)>
+    where
+        S: HasSource<Ast = Ast>,
+        Ast: AstNode + ast::VisibilityOwner,
+    {
+        let source = x.source(db)?;
+        let in_file_syntax = source.syntax();
+        let file_id = in_file_syntax.file_id;
+        let syntax = in_file_syntax.value;
+        let current_visibility = source.value.visibility();
+        Some((
+            vis_offset(syntax),
+            current_visibility,
+            syntax.text_range(),
+            file_id.original_file(db.upcast()),
+        ))
+    }
+
+    let target_name;
+    let (offset, current_visibility, target, target_file) = match def {
+        hir::ModuleDef::Function(f) => {
+            target_name = Some(f.name(db));
+            offset_target_and_file_id(db, f)?
+        }
+        hir::ModuleDef::Adt(adt) => {
+            target_name = Some(adt.name(db));
+            match adt {
+                hir::Adt::Struct(s) => offset_target_and_file_id(db, s)?,
+                hir::Adt::Union(u) => offset_target_and_file_id(db, u)?,
+                hir::Adt::Enum(e) => offset_target_and_file_id(db, e)?,
+            }
+        }
+        hir::ModuleDef::Const(c) => {
+            target_name = c.name(db);
+            offset_target_and_file_id(db, c)?
+        }
+        hir::ModuleDef::Static(s) => {
+            target_name = s.name(db);
+            offset_target_and_file_id(db, s)?
+        }
+        hir::ModuleDef::Trait(t) => {
+            target_name = Some(t.name(db));
+            offset_target_and_file_id(db, t)?
+        }
+        hir::ModuleDef::TypeAlias(t) => {
+            target_name = Some(t.name(db));
+            offset_target_and_file_id(db, t)?
+        }
+        hir::ModuleDef::Module(m) => {
+            target_name = m.name(db);
+            let in_file_source = m.declaration_source(db)?;
+            let file_id = in_file_source.file_id.original_file(db.upcast());
+            let syntax = in_file_source.value.syntax();
+            (vis_offset(syntax), in_file_source.value.visibility(), syntax.text_range(), file_id)
+        }
+        // Enum variants can't be private, we can't modify builtin types
+        hir::ModuleDef::Variant(_) | hir::ModuleDef::BuiltinType(_) => return None,
+    };
+
+    Some((offset, current_visibility, target, target_file, target_name))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn fix_visibility_of_fn() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { fn foo() {} }
+              fn main() { foo::foo$0() } ",
+            r"mod foo { $0pub(crate) fn foo() {} }
+              fn main() { foo::foo() } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub fn foo() {} }
+              fn main() { foo::foo$0() } ",
+        )
+    }
+
+    #[test]
+    fn fix_visibility_of_adt_in_submodule() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { struct Foo; }
+              fn main() { foo::Foo$0 } ",
+            r"mod foo { $0pub(crate) struct Foo; }
+              fn main() { foo::Foo } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub struct Foo; }
+              fn main() { foo::Foo$0 } ",
+        );
+        check_assist(
+            fix_visibility,
+            r"mod foo { enum Foo; }
+              fn main() { foo::Foo$0 } ",
+            r"mod foo { $0pub(crate) enum Foo; }
+              fn main() { foo::Foo } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub enum Foo; }
+              fn main() { foo::Foo$0 } ",
+        );
+        check_assist(
+            fix_visibility,
+            r"mod foo { union Foo; }
+              fn main() { foo::Foo$0 } ",
+            r"mod foo { $0pub(crate) union Foo; }
+              fn main() { foo::Foo } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub union Foo; }
+              fn main() { foo::Foo$0 } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_adt_in_other_file() {
+        check_assist(
+            fix_visibility,
+            r"
+//- /main.rs
+mod foo;
+fn main() { foo::Foo$0 }
+
+//- /foo.rs
+struct Foo;
+",
+            r"$0pub(crate) struct Foo;
+",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_struct_field() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { pub struct Foo { bar: (), } }
+              fn main() { foo::Foo { $0bar: () }; } ",
+            r"mod foo { pub struct Foo { $0pub(crate) bar: (), } }
+              fn main() { foo::Foo { bar: () }; } ",
+        );
+        check_assist(
+            fix_visibility,
+            r"
+//- /lib.rs
+mod foo;
+fn main() { foo::Foo { $0bar: () }; }
+//- /foo.rs
+pub struct Foo { bar: () }
+",
+            r"pub struct Foo { $0pub(crate) bar: () }
+",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub struct Foo { pub bar: (), } }
+              fn main() { foo::Foo { $0bar: () }; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"
+//- /lib.rs
+mod foo;
+fn main() { foo::Foo { $0bar: () }; }
+//- /foo.rs
+pub struct Foo { pub bar: () }
+",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_enum_variant_field() {
+        // Enum variants, as well as their fields, always get the enum's visibility. In fact, rustc
+        // rejects any visibility specifiers on them, so this assist should never fire on them.
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub enum Foo { Bar { bar: () } } }
+              fn main() { foo::Foo::Bar { $0bar: () }; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"
+//- /lib.rs
+mod foo;
+fn main() { foo::Foo::Bar { $0bar: () }; }
+//- /foo.rs
+pub enum Foo { Bar { bar: () } }
+",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub struct Foo { pub bar: (), } }
+              fn main() { foo::Foo { $0bar: () }; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"
+//- /lib.rs
+mod foo;
+fn main() { foo::Foo { $0bar: () }; }
+//- /foo.rs
+pub struct Foo { pub bar: () }
+",
+        );
+    }
+
+    #[test]
+    #[ignore]
+    // FIXME reenable this test when `Semantics::resolve_record_field` works with union fields
+    fn fix_visibility_of_union_field() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { pub union Foo { bar: (), } }
+              fn main() { foo::Foo { $0bar: () }; } ",
+            r"mod foo { pub union Foo { $0pub(crate) bar: (), } }
+              fn main() { foo::Foo { bar: () }; } ",
+        );
+        check_assist(
+            fix_visibility,
+            r"
+//- /lib.rs
+mod foo;
+fn main() { foo::Foo { $0bar: () }; }
+//- /foo.rs
+pub union Foo { bar: () }
+",
+            r"pub union Foo { $0pub(crate) bar: () }
+",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub union Foo { pub bar: (), } }
+              fn main() { foo::Foo { $0bar: () }; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"
+//- /lib.rs
+mod foo;
+fn main() { foo::Foo { $0bar: () }; }
+//- /foo.rs
+pub union Foo { pub bar: () }
+",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_const() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { const FOO: () = (); }
+              fn main() { foo::FOO$0 } ",
+            r"mod foo { $0pub(crate) const FOO: () = (); }
+              fn main() { foo::FOO } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub const FOO: () = (); }
+              fn main() { foo::FOO$0 } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_static() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { static FOO: () = (); }
+              fn main() { foo::FOO$0 } ",
+            r"mod foo { $0pub(crate) static FOO: () = (); }
+              fn main() { foo::FOO } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub static FOO: () = (); }
+              fn main() { foo::FOO$0 } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_trait() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { trait Foo { fn foo(&self) {} } }
+              fn main() { let x: &dyn foo::$0Foo; } ",
+            r"mod foo { $0pub(crate) trait Foo { fn foo(&self) {} } }
+              fn main() { let x: &dyn foo::Foo; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub trait Foo { fn foo(&self) {} } }
+              fn main() { let x: &dyn foo::Foo$0; } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_type_alias() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { type Foo = (); }
+              fn main() { let x: foo::Foo$0; } ",
+            r"mod foo { $0pub(crate) type Foo = (); }
+              fn main() { let x: foo::Foo; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub type Foo = (); }
+              fn main() { let x: foo::Foo$0; } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_module() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { mod bar { fn bar() {} } }
+              fn main() { foo::bar$0::bar(); } ",
+            r"mod foo { $0pub(crate) mod bar { fn bar() {} } }
+              fn main() { foo::bar::bar(); } ",
+        );
+
+        check_assist(
+            fix_visibility,
+            r"
+//- /main.rs
+mod foo;
+fn main() { foo::bar$0::baz(); }
+
+//- /foo.rs
+mod bar {
+    pub fn baz() {}
+}
+",
+            r"$0pub(crate) mod bar {
+    pub fn baz() {}
+}
+",
+        );
+
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub mod bar { pub fn bar() {} } }
+              fn main() { foo::bar$0::bar(); } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_inline_module_in_other_file() {
+        check_assist(
+            fix_visibility,
+            r"
+//- /main.rs
+mod foo;
+fn main() { foo::bar$0::baz(); }
+
+//- /foo.rs
+mod bar;
+//- /foo/bar.rs
+pub fn baz() {}
+",
+            r"$0pub(crate) mod bar;
+",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_module_declaration_in_other_file() {
+        check_assist(
+            fix_visibility,
+            r"
+//- /main.rs
+mod foo;
+fn main() { foo::bar$0>::baz(); }
+
+//- /foo.rs
+mod bar {
+    pub fn baz() {}
+}
+",
+            r"$0pub(crate) mod bar {
+    pub fn baz() {}
+}
+",
+        );
+    }
+
+    #[test]
+    fn adds_pub_when_target_is_in_another_crate() {
+        check_assist(
+            fix_visibility,
+            r"
+//- /main.rs crate:a deps:foo
+foo::Bar$0
+//- /lib.rs crate:foo
+struct Bar;
+",
+            r"$0pub struct Bar;
+",
+        )
+    }
+
+    #[test]
+    fn replaces_pub_crate_with_pub() {
+        check_assist(
+            fix_visibility,
+            r"
+//- /main.rs crate:a deps:foo
+foo::Bar$0
+//- /lib.rs crate:foo
+pub(crate) struct Bar;
+",
+            r"$0pub struct Bar;
+",
+        );
+        check_assist(
+            fix_visibility,
+            r"
+//- /main.rs crate:a deps:foo
+fn main() {
+    foo::Foo { $0bar: () };
+}
+//- /lib.rs crate:foo
+pub struct Foo { pub(crate) bar: () }
+",
+            r"pub struct Foo { $0pub bar: () }
+",
+        );
+    }
+
+    #[test]
+    #[ignore]
+    // FIXME handle reexports properly
+    fn fix_visibility_of_reexport() {
+        check_assist(
+            fix_visibility,
+            r"
+            mod foo {
+                use bar::Baz;
+                mod bar { pub(super) struct Baz; }
+            }
+            foo::Baz$0
+            ",
+            r"
+            mod foo {
+                $0pub(crate) use bar::Baz;
+                mod bar { pub(super) struct Baz; }
+            }
+            foo::Baz
+            ",
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/flip_binexpr.rs b/crates/ide_assists/src/handlers/flip_binexpr.rs
new file mode 100644
index 000000000..209e5d43c
--- /dev/null
+++ b/crates/ide_assists/src/handlers/flip_binexpr.rs
@@ -0,0 +1,134 @@
+use syntax::ast::{AstNode, BinExpr, BinOp};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: flip_binexpr
+//
+// Flips operands of a binary expression.
+//
+// ```
+// fn main() {
+//     let _ = 90 +$0 2;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     let _ = 2 + 90;
+// }
+// ```
+pub(crate) fn flip_binexpr(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let expr = ctx.find_node_at_offset::<BinExpr>()?;
+    let lhs = expr.lhs()?.syntax().clone();
+    let rhs = expr.rhs()?.syntax().clone();
+    let op_range = expr.op_token()?.text_range();
+    // The assist should be applied only if the cursor is on the operator
+    let cursor_in_range = op_range.contains_range(ctx.frange.range);
+    if !cursor_in_range {
+        return None;
+    }
+    let action: FlipAction = expr.op_kind()?.into();
+    // The assist should not be applied for certain operators
+    if let FlipAction::DontFlip = action {
+        return None;
+    }
+
+    acc.add(
+        AssistId("flip_binexpr", AssistKind::RefactorRewrite),
+        "Flip binary expression",
+        op_range,
+        |edit| {
+            if let FlipAction::FlipAndReplaceOp(new_op) = action {
+                edit.replace(op_range, new_op);
+            }
+            edit.replace(lhs.text_range(), rhs.text());
+            edit.replace(rhs.text_range(), lhs.text());
+        },
+    )
+}
+
+enum FlipAction {
+    // Flip the expression
+    Flip,
+    // Flip the expression and replace the operator with this string
+    FlipAndReplaceOp(&'static str),
+    // Do not flip the expression
+    DontFlip,
+}
+
+impl From<BinOp> for FlipAction {
+    fn from(op_kind: BinOp) -> Self {
+        match op_kind {
+            kind if kind.is_assignment() => FlipAction::DontFlip,
+            BinOp::GreaterTest => FlipAction::FlipAndReplaceOp("<"),
+            BinOp::GreaterEqualTest => FlipAction::FlipAndReplaceOp("<="),
+            BinOp::LesserTest => FlipAction::FlipAndReplaceOp(">"),
+            BinOp::LesserEqualTest => FlipAction::FlipAndReplaceOp(">="),
+            _ => FlipAction::Flip,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    #[test]
+    fn flip_binexpr_target_is_the_op() {
+        check_assist_target(flip_binexpr, "fn f() { let res = 1 ==$0 2; }", "==")
+    }
+
+    #[test]
+    fn flip_binexpr_not_applicable_for_assignment() {
+        check_assist_not_applicable(flip_binexpr, "fn f() { let mut _x = 1; _x +=$0 2 }")
+    }
+
+    #[test]
+    fn flip_binexpr_works_for_eq() {
+        check_assist(flip_binexpr, "fn f() { let res = 1 ==$0 2; }", "fn f() { let res = 2 == 1; }")
+    }
+
+    #[test]
+    fn flip_binexpr_works_for_gt() {
+        check_assist(flip_binexpr, "fn f() { let res = 1 >$0 2; }", "fn f() { let res = 2 < 1; }")
+    }
+
+    #[test]
+    fn flip_binexpr_works_for_lteq() {
+        check_assist(flip_binexpr, "fn f() { let res = 1 <=$0 2; }", "fn f() { let res = 2 >= 1; }")
+    }
+
+    #[test]
+    fn flip_binexpr_works_for_complex_expr() {
+        check_assist(
+            flip_binexpr,
+            "fn f() { let res = (1 + 1) ==$0 (2 + 2); }",
+            "fn f() { let res = (2 + 2) == (1 + 1); }",
+        )
+    }
+
+    #[test]
+    fn flip_binexpr_works_inside_match() {
+        check_assist(
+            flip_binexpr,
+            r#"
+            fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
+                match other.downcast_ref::<Self>() {
+                    None => false,
+                    Some(it) => it ==$0 self,
+                }
+            }
+            "#,
+            r#"
+            fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
+                match other.downcast_ref::<Self>() {
+                    None => false,
+                    Some(it) => self == it,
+                }
+            }
+            "#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/flip_comma.rs b/crates/ide_assists/src/handlers/flip_comma.rs
new file mode 100644
index 000000000..18cf64a34
--- /dev/null
+++ b/crates/ide_assists/src/handlers/flip_comma.rs
@@ -0,0 +1,84 @@
+use syntax::{algo::non_trivia_sibling, Direction, T};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: flip_comma
+//
+// Flips two comma-separated items.
+//
+// ```
+// fn main() {
+//     ((1, 2),$0 (3, 4));
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     ((3, 4), (1, 2));
+// }
+// ```
+pub(crate) fn flip_comma(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let comma = ctx.find_token_syntax_at_offset(T![,])?;
+    let prev = non_trivia_sibling(comma.clone().into(), Direction::Prev)?;
+    let next = non_trivia_sibling(comma.clone().into(), Direction::Next)?;
+
+    // Don't apply a "flip" in case of a last comma
+    // that typically comes before punctuation
+    if next.kind().is_punct() {
+        return None;
+    }
+
+    acc.add(
+        AssistId("flip_comma", AssistKind::RefactorRewrite),
+        "Flip comma",
+        comma.text_range(),
+        |edit| {
+            edit.replace(prev.text_range(), next.to_string());
+            edit.replace(next.text_range(), prev.to_string());
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_target};
+
+    #[test]
+    fn flip_comma_works_for_function_parameters() {
+        check_assist(
+            flip_comma,
+            r#"fn foo(x: i32,$0 y: Result<(), ()>) {}"#,
+            r#"fn foo(y: Result<(), ()>, x: i32) {}"#,
+        )
+    }
+
+    #[test]
+    fn flip_comma_target() {
+        check_assist_target(flip_comma, r#"fn foo(x: i32,$0 y: Result<(), ()>) {}"#, ",")
+    }
+
+    #[test]
+    #[should_panic]
+    fn flip_comma_before_punct() {
+        // See https://github.com/rust-analyzer/rust-analyzer/issues/1619
+        // "Flip comma" assist shouldn't be applicable to the last comma in enum or struct
+        // declaration body.
+        check_assist_target(
+            flip_comma,
+            "pub enum Test { \
+             A,$0 \
+             }",
+            ",",
+        );
+
+        check_assist_target(
+            flip_comma,
+            "pub struct Test { \
+             foo: usize,$0 \
+             }",
+            ",",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/flip_trait_bound.rs b/crates/ide_assists/src/handlers/flip_trait_bound.rs
new file mode 100644
index 000000000..d419d263e
--- /dev/null
+++ b/crates/ide_assists/src/handlers/flip_trait_bound.rs
@@ -0,0 +1,121 @@
+use syntax::{
+    algo::non_trivia_sibling,
+    ast::{self, AstNode},
+    Direction, T,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: flip_trait_bound
+//
+// Flips two trait bounds.
+//
+// ```
+// fn foo<T: Clone +$0 Copy>() { }
+// ```
+// ->
+// ```
+// fn foo<T: Copy + Clone>() { }
+// ```
+pub(crate) fn flip_trait_bound(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    // We want to replicate the behavior of `flip_binexpr` by only suggesting
+    // the assist when the cursor is on a `+`
+    let plus = ctx.find_token_syntax_at_offset(T![+])?;
+
+    // Make sure we're in a `TypeBoundList`
+    if ast::TypeBoundList::cast(plus.parent()).is_none() {
+        return None;
+    }
+
+    let (before, after) = (
+        non_trivia_sibling(plus.clone().into(), Direction::Prev)?,
+        non_trivia_sibling(plus.clone().into(), Direction::Next)?,
+    );
+
+    let target = plus.text_range();
+    acc.add(
+        AssistId("flip_trait_bound", AssistKind::RefactorRewrite),
+        "Flip trait bounds",
+        target,
+        |edit| {
+            edit.replace(before.text_range(), after.to_string());
+            edit.replace(after.text_range(), before.to_string());
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    #[test]
+    fn flip_trait_bound_assist_available() {
+        check_assist_target(flip_trait_bound, "struct S<T> where T: A $0+ B + C { }", "+")
+    }
+
+    #[test]
+    fn flip_trait_bound_not_applicable_for_single_trait_bound() {
+        check_assist_not_applicable(flip_trait_bound, "struct S<T> where T: $0A { }")
+    }
+
+    #[test]
+    fn flip_trait_bound_works_for_struct() {
+        check_assist(
+            flip_trait_bound,
+            "struct S<T> where T: A $0+ B { }",
+            "struct S<T> where T: B + A { }",
+        )
+    }
+
+    #[test]
+    fn flip_trait_bound_works_for_trait_impl() {
+        check_assist(
+            flip_trait_bound,
+            "impl X for S<T> where T: A +$0 B { }",
+            "impl X for S<T> where T: B + A { }",
+        )
+    }
+
+    #[test]
+    fn flip_trait_bound_works_for_fn() {
+        check_assist(flip_trait_bound, "fn f<T: A $0+ B>(t: T) { }", "fn f<T: B + A>(t: T) { }")
+    }
+
+    #[test]
+    fn flip_trait_bound_works_for_fn_where_clause() {
+        check_assist(
+            flip_trait_bound,
+            "fn f<T>(t: T) where T: A +$0 B { }",
+            "fn f<T>(t: T) where T: B + A { }",
+        )
+    }
+
+    #[test]
+    fn flip_trait_bound_works_for_lifetime() {
+        check_assist(
+            flip_trait_bound,
+            "fn f<T>(t: T) where T: A $0+ 'static { }",
+            "fn f<T>(t: T) where T: 'static + A { }",
+        )
+    }
+
+    #[test]
+    fn flip_trait_bound_works_for_complex_bounds() {
+        check_assist(
+            flip_trait_bound,
+            "struct S<T> where T: A<T> $0+ b_mod::B<T> + C<T> { }",
+            "struct S<T> where T: b_mod::B<T> + A<T> + C<T> { }",
+        )
+    }
+
+    #[test]
+    fn flip_trait_bound_works_for_long_bounds() {
+        check_assist(
+            flip_trait_bound,
+            "struct S<T> where T: A + B + C + D + E + F +$0 G + H + I + J { }",
+            "struct S<T> where T: A + B + C + D + E + G + F + H + I + J { }",
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_default_from_enum_variant.rs b/crates/ide_assists/src/handlers/generate_default_from_enum_variant.rs
new file mode 100644
index 000000000..6a2ab9596
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_default_from_enum_variant.rs
@@ -0,0 +1,175 @@
+use ide_db::helpers::FamousDefs;
+use ide_db::RootDatabase;
+use syntax::ast::{self, AstNode, NameOwner};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: generate_default_from_enum_variant
+//
+// Adds a Default impl for an enum using a variant.
+//
+// ```
+// enum Version {
+//  Undefined,
+//  Minor$0,
+//  Major,
+// }
+// ```
+// ->
+// ```
+// enum Version {
+//  Undefined,
+//  Minor,
+//  Major,
+// }
+//
+// impl Default for Version {
+//     fn default() -> Self {
+//         Self::Minor
+//     }
+// }
+// ```
+pub(crate) fn generate_default_from_enum_variant(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+) -> Option<()> {
+    let variant = ctx.find_node_at_offset::<ast::Variant>()?;
+    let variant_name = variant.name()?;
+    let enum_name = variant.parent_enum().name()?;
+    if !matches!(variant.kind(), ast::StructKind::Unit) {
+        mark::hit!(test_gen_default_on_non_unit_variant_not_implemented);
+        return None;
+    }
+
+    if existing_default_impl(&ctx.sema, &variant).is_some() {
+        mark::hit!(test_gen_default_impl_already_exists);
+        return None;
+    }
+
+    let target = variant.syntax().text_range();
+    acc.add(
+        AssistId("generate_default_from_enum_variant", AssistKind::Generate),
+        "Generate `Default` impl from this enum variant",
+        target,
+        |edit| {
+            let start_offset = variant.parent_enum().syntax().text_range().end();
+            let buf = format!(
+                r#"
+
+impl Default for {0} {{
+    fn default() -> Self {{
+        Self::{1}
+    }}
+}}"#,
+                enum_name, variant_name
+            );
+            edit.insert(start_offset, buf);
+        },
+    )
+}
+
+fn existing_default_impl(
+    sema: &'_ hir::Semantics<'_, RootDatabase>,
+    variant: &ast::Variant,
+) -> Option<()> {
+    let variant = sema.to_def(variant)?;
+    let enum_ = variant.parent_enum(sema.db);
+    let krate = enum_.module(sema.db).krate();
+
+    let default_trait = FamousDefs(sema, Some(krate)).core_default_Default()?;
+    let enum_type = enum_.ty(sema.db);
+
+    if enum_type.impls_trait(sema.db, default_trait, &[]) {
+        Some(())
+    } else {
+        None
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    fn check_not_applicable(ra_fixture: &str) {
+        let fixture =
+            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
+        check_assist_not_applicable(generate_default_from_enum_variant, &fixture)
+    }
+
+    #[test]
+    fn test_generate_default_from_variant() {
+        check_assist(
+            generate_default_from_enum_variant,
+            r#"
+enum Variant {
+    Undefined,
+    Minor$0,
+    Major,
+}"#,
+            r#"enum Variant {
+    Undefined,
+    Minor,
+    Major,
+}
+
+impl Default for Variant {
+    fn default() -> Self {
+        Self::Minor
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_default_already_implemented() {
+        mark::check!(test_gen_default_impl_already_exists);
+        check_not_applicable(
+            r#"
+enum Variant {
+    Undefined,
+    Minor$0,
+    Major,
+}
+
+impl Default for Variant {
+    fn default() -> Self {
+        Self::Minor
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_add_from_impl_no_element() {
+        mark::check!(test_gen_default_on_non_unit_variant_not_implemented);
+        check_not_applicable(
+            r#"
+enum Variant {
+    Undefined,
+    Minor(u32)$0,
+    Major,
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_default_from_variant_with_one_variant() {
+        check_assist(
+            generate_default_from_enum_variant,
+            r#"enum Variant { Undefi$0ned }"#,
+            r#"
+enum Variant { Undefined }
+
+impl Default for Variant {
+    fn default() -> Self {
+        Self::Undefined
+    }
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_derive.rs b/crates/ide_assists/src/handlers/generate_derive.rs
new file mode 100644
index 000000000..adae8ab7e
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_derive.rs
@@ -0,0 +1,132 @@
+use syntax::{
+    ast::{self, AstNode, AttrsOwner},
+    SyntaxKind::{COMMENT, WHITESPACE},
+    TextSize,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: generate_derive
+//
+// Adds a new `#[derive()]` clause to a struct or enum.
+//
+// ```
+// struct Point {
+//     x: u32,
+//     y: u32,$0
+// }
+// ```
+// ->
+// ```
+// #[derive($0)]
+// struct Point {
+//     x: u32,
+//     y: u32,
+// }
+// ```
+pub(crate) fn generate_derive(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let cap = ctx.config.snippet_cap?;
+    let nominal = ctx.find_node_at_offset::<ast::Adt>()?;
+    let node_start = derive_insertion_offset(&nominal)?;
+    let target = nominal.syntax().text_range();
+    acc.add(
+        AssistId("generate_derive", AssistKind::Generate),
+        "Add `#[derive]`",
+        target,
+        |builder| {
+            let derive_attr = nominal
+                .attrs()
+                .filter_map(|x| x.as_simple_call())
+                .filter(|(name, _arg)| name == "derive")
+                .map(|(_name, arg)| arg)
+                .next();
+            match derive_attr {
+                None => {
+                    builder.insert_snippet(cap, node_start, "#[derive($0)]\n");
+                }
+                Some(tt) => {
+                    // Just move the cursor.
+                    builder.insert_snippet(
+                        cap,
+                        tt.syntax().text_range().end() - TextSize::of(')'),
+                        "$0",
+                    )
+                }
+            };
+        },
+    )
+}
+
+// Insert `derive` after doc comments.
+fn derive_insertion_offset(nominal: &ast::Adt) -> Option<TextSize> {
+    let non_ws_child = nominal
+        .syntax()
+        .children_with_tokens()
+        .find(|it| it.kind() != COMMENT && it.kind() != WHITESPACE)?;
+    Some(non_ws_child.text_range().start())
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn add_derive_new() {
+        check_assist(
+            generate_derive,
+            "struct Foo { a: i32, $0}",
+            "#[derive($0)]\nstruct Foo { a: i32, }",
+        );
+        check_assist(
+            generate_derive,
+            "struct Foo { $0 a: i32, }",
+            "#[derive($0)]\nstruct Foo {  a: i32, }",
+        );
+    }
+
+    #[test]
+    fn add_derive_existing() {
+        check_assist(
+            generate_derive,
+            "#[derive(Clone)]\nstruct Foo { a: i32$0, }",
+            "#[derive(Clone$0)]\nstruct Foo { a: i32, }",
+        );
+    }
+
+    #[test]
+    fn add_derive_new_with_doc_comment() {
+        check_assist(
+            generate_derive,
+            "
+/// `Foo` is a pretty important struct.
+/// It does stuff.
+struct Foo { a: i32$0, }
+            ",
+            "
+/// `Foo` is a pretty important struct.
+/// It does stuff.
+#[derive($0)]
+struct Foo { a: i32, }
+            ",
+        );
+    }
+
+    #[test]
+    fn add_derive_target() {
+        check_assist_target(
+            generate_derive,
+            "
+struct SomeThingIrrelevant;
+/// `Foo` is a pretty important struct.
+/// It does stuff.
+struct Foo { a: i32$0, }
+struct EvenMoreIrrelevant;
+            ",
+            "/// `Foo` is a pretty important struct.
+/// It does stuff.
+struct Foo { a: i32, }",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_enum_match_method.rs b/crates/ide_assists/src/handlers/generate_enum_match_method.rs
new file mode 100644
index 000000000..aeb887e71
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_enum_match_method.rs
@@ -0,0 +1,240 @@
+use stdx::{format_to, to_lower_snake_case};
+use syntax::ast::VisibilityOwner;
+use syntax::ast::{self, AstNode, NameOwner};
+use test_utils::mark;
+
+use crate::{
+    utils::{find_impl_block_end, find_struct_impl, generate_impl_text},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: generate_enum_match_method
+//
+// Generate an `is_` method for an enum variant.
+//
+// ```
+// enum Version {
+//  Undefined,
+//  Minor$0,
+//  Major,
+// }
+// ```
+// ->
+// ```
+// enum Version {
+//  Undefined,
+//  Minor,
+//  Major,
+// }
+//
+// impl Version {
+//     /// Returns `true` if the version is [`Minor`].
+//     fn is_minor(&self) -> bool {
+//         matches!(self, Self::Minor)
+//     }
+// }
+// ```
+pub(crate) fn generate_enum_match_method(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let variant = ctx.find_node_at_offset::<ast::Variant>()?;
+    let variant_name = variant.name()?;
+    let parent_enum = variant.parent_enum();
+    if !matches!(variant.kind(), ast::StructKind::Unit) {
+        mark::hit!(test_gen_enum_match_on_non_unit_variant_not_implemented);
+        return None;
+    }
+
+    let enum_lowercase_name = to_lower_snake_case(&parent_enum.name()?.to_string());
+    let fn_name = to_lower_snake_case(&variant_name.to_string());
+
+    // Return early if we've found an existing new fn
+    let impl_def = find_struct_impl(
+        &ctx,
+        &ast::Adt::Enum(parent_enum.clone()),
+        format!("is_{}", fn_name).as_str(),
+    )?;
+
+    let target = variant.syntax().text_range();
+    acc.add(
+        AssistId("generate_enum_match_method", AssistKind::Generate),
+        "Generate an `is_` method for an enum variant",
+        target,
+        |builder| {
+            let mut buf = String::with_capacity(512);
+
+            if impl_def.is_some() {
+                buf.push('\n');
+            }
+
+            let vis = parent_enum.visibility().map_or(String::new(), |v| format!("{} ", v));
+            format_to!(
+                buf,
+                "    /// Returns `true` if the {} is [`{}`].
+    {}fn is_{}(&self) -> bool {{
+        matches!(self, Self::{})
+    }}",
+                enum_lowercase_name,
+                variant_name,
+                vis,
+                fn_name,
+                variant_name
+            );
+
+            let start_offset = impl_def
+                .and_then(|impl_def| find_impl_block_end(impl_def, &mut buf))
+                .unwrap_or_else(|| {
+                    buf = generate_impl_text(&ast::Adt::Enum(parent_enum.clone()), &buf);
+                    parent_enum.syntax().text_range().end()
+                });
+
+            builder.insert(start_offset, buf);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    fn check_not_applicable(ra_fixture: &str) {
+        check_assist_not_applicable(generate_enum_match_method, ra_fixture)
+    }
+
+    #[test]
+    fn test_generate_enum_match_from_variant() {
+        check_assist(
+            generate_enum_match_method,
+            r#"
+enum Variant {
+    Undefined,
+    Minor$0,
+    Major,
+}"#,
+            r#"enum Variant {
+    Undefined,
+    Minor,
+    Major,
+}
+
+impl Variant {
+    /// Returns `true` if the variant is [`Minor`].
+    fn is_minor(&self) -> bool {
+        matches!(self, Self::Minor)
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_match_already_implemented() {
+        check_not_applicable(
+            r#"
+enum Variant {
+    Undefined,
+    Minor$0,
+    Major,
+}
+
+impl Variant {
+    fn is_minor(&self) -> bool {
+        matches!(self, Self::Minor)
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_add_from_impl_no_element() {
+        mark::check!(test_gen_enum_match_on_non_unit_variant_not_implemented);
+        check_not_applicable(
+            r#"
+enum Variant {
+    Undefined,
+    Minor(u32)$0,
+    Major,
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_match_from_variant_with_one_variant() {
+        check_assist(
+            generate_enum_match_method,
+            r#"enum Variant { Undefi$0ned }"#,
+            r#"
+enum Variant { Undefined }
+
+impl Variant {
+    /// Returns `true` if the variant is [`Undefined`].
+    fn is_undefined(&self) -> bool {
+        matches!(self, Self::Undefined)
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_enum_match_from_variant_with_visibility_marker() {
+        check_assist(
+            generate_enum_match_method,
+            r#"
+pub(crate) enum Variant {
+    Undefined,
+    Minor$0,
+    Major,
+}"#,
+            r#"pub(crate) enum Variant {
+    Undefined,
+    Minor,
+    Major,
+}
+
+impl Variant {
+    /// Returns `true` if the variant is [`Minor`].
+    pub(crate) fn is_minor(&self) -> bool {
+        matches!(self, Self::Minor)
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_multiple_generate_enum_match_from_variant() {
+        check_assist(
+            generate_enum_match_method,
+            r#"
+enum Variant {
+    Undefined,
+    Minor,
+    Major$0,
+}
+
+impl Variant {
+    /// Returns `true` if the variant is [`Minor`].
+    fn is_minor(&self) -> bool {
+        matches!(self, Self::Minor)
+    }
+}"#,
+            r#"enum Variant {
+    Undefined,
+    Minor,
+    Major,
+}
+
+impl Variant {
+    /// Returns `true` if the variant is [`Minor`].
+    fn is_minor(&self) -> bool {
+        matches!(self, Self::Minor)
+    }
+
+    /// Returns `true` if the variant is [`Major`].
+    fn is_major(&self) -> bool {
+        matches!(self, Self::Major)
+    }
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
new file mode 100644
index 000000000..d9388a737
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_from_impl_for_enum.rs
@@ -0,0 +1,268 @@
+use ide_db::helpers::FamousDefs;
+use ide_db::RootDatabase;
+use syntax::ast::{self, AstNode, NameOwner};
+use test_utils::mark;
+
+use crate::{utils::generate_trait_impl_text, AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: generate_from_impl_for_enum
+//
+// Adds a From impl for an enum variant with one tuple field.
+//
+// ```
+// enum A { $0One(u32) }
+// ```
+// ->
+// ```
+// enum A { One(u32) }
+//
+// impl From<u32> for A {
+//     fn from(v: u32) -> Self {
+//         Self::One(v)
+//     }
+// }
+// ```
+pub(crate) fn generate_from_impl_for_enum(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let variant = ctx.find_node_at_offset::<ast::Variant>()?;
+    let variant_name = variant.name()?;
+    let enum_ = ast::Adt::Enum(variant.parent_enum());
+    let (field_name, field_type) = match variant.kind() {
+        ast::StructKind::Tuple(field_list) => {
+            if field_list.fields().count() != 1 {
+                return None;
+            }
+            (None, field_list.fields().next()?.ty()?)
+        }
+        ast::StructKind::Record(field_list) => {
+            if field_list.fields().count() != 1 {
+                return None;
+            }
+            let field = field_list.fields().next()?;
+            (Some(field.name()?), field.ty()?)
+        }
+        ast::StructKind::Unit => return None,
+    };
+
+    if existing_from_impl(&ctx.sema, &variant).is_some() {
+        mark::hit!(test_add_from_impl_already_exists);
+        return None;
+    }
+
+    let target = variant.syntax().text_range();
+    acc.add(
+        AssistId("generate_from_impl_for_enum", AssistKind::Generate),
+        "Generate `From` impl for this enum variant",
+        target,
+        |edit| {
+            let start_offset = variant.parent_enum().syntax().text_range().end();
+            let from_trait = format!("From<{}>", field_type.syntax());
+            let impl_code = if let Some(name) = field_name {
+                format!(
+                    r#"    fn from({0}: {1}) -> Self {{
+        Self::{2} {{ {0} }}
+    }}"#,
+                    name.text(),
+                    field_type.syntax(),
+                    variant_name,
+                )
+            } else {
+                format!(
+                    r#"    fn from(v: {}) -> Self {{
+        Self::{}(v)
+    }}"#,
+                    field_type.syntax(),
+                    variant_name,
+                )
+            };
+            let from_impl = generate_trait_impl_text(&enum_, &from_trait, &impl_code);
+            edit.insert(start_offset, from_impl);
+        },
+    )
+}
+
+fn existing_from_impl(
+    sema: &'_ hir::Semantics<'_, RootDatabase>,
+    variant: &ast::Variant,
+) -> Option<()> {
+    let variant = sema.to_def(variant)?;
+    let enum_ = variant.parent_enum(sema.db);
+    let krate = enum_.module(sema.db).krate();
+
+    let from_trait = FamousDefs(sema, Some(krate)).core_convert_From()?;
+
+    let enum_type = enum_.ty(sema.db);
+
+    let wrapped_type = variant.fields(sema.db).get(0)?.signature_ty(sema.db);
+
+    if enum_type.impls_trait(sema.db, from_trait, &[wrapped_type]) {
+        Some(())
+    } else {
+        None
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn test_generate_from_impl_for_enum() {
+        check_assist(
+            generate_from_impl_for_enum,
+            "enum A { $0One(u32) }",
+            r#"enum A { One(u32) }
+
+impl From<u32> for A {
+    fn from(v: u32) -> Self {
+        Self::One(v)
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_from_impl_for_enum_complicated_path() {
+        check_assist(
+            generate_from_impl_for_enum,
+            r#"enum A { $0One(foo::bar::baz::Boo) }"#,
+            r#"enum A { One(foo::bar::baz::Boo) }
+
+impl From<foo::bar::baz::Boo> for A {
+    fn from(v: foo::bar::baz::Boo) -> Self {
+        Self::One(v)
+    }
+}"#,
+        );
+    }
+
+    fn check_not_applicable(ra_fixture: &str) {
+        let fixture =
+            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
+        check_assist_not_applicable(generate_from_impl_for_enum, &fixture)
+    }
+
+    #[test]
+    fn test_add_from_impl_no_element() {
+        check_not_applicable("enum A { $0One }");
+    }
+
+    #[test]
+    fn test_add_from_impl_more_than_one_element_in_tuple() {
+        check_not_applicable("enum A { $0One(u32, String) }");
+    }
+
+    #[test]
+    fn test_add_from_impl_struct_variant() {
+        check_assist(
+            generate_from_impl_for_enum,
+            "enum A { $0One { x: u32 } }",
+            r#"enum A { One { x: u32 } }
+
+impl From<u32> for A {
+    fn from(x: u32) -> Self {
+        Self::One { x }
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_add_from_impl_already_exists() {
+        mark::check!(test_add_from_impl_already_exists);
+        check_not_applicable(
+            r#"
+enum A { $0One(u32), }
+
+impl From<u32> for A {
+    fn from(v: u32) -> Self {
+        Self::One(v)
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn test_add_from_impl_different_variant_impl_exists() {
+        check_assist(
+            generate_from_impl_for_enum,
+            r#"enum A { $0One(u32), Two(String), }
+
+impl From<String> for A {
+    fn from(v: String) -> Self {
+        A::Two(v)
+    }
+}
+
+pub trait From<T> {
+    fn from(T) -> Self;
+}"#,
+            r#"enum A { One(u32), Two(String), }
+
+impl From<u32> for A {
+    fn from(v: u32) -> Self {
+        Self::One(v)
+    }
+}
+
+impl From<String> for A {
+    fn from(v: String) -> Self {
+        A::Two(v)
+    }
+}
+
+pub trait From<T> {
+    fn from(T) -> Self;
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_add_from_impl_static_str() {
+        check_assist(
+            generate_from_impl_for_enum,
+            "enum A { $0One(&'static str) }",
+            r#"enum A { One(&'static str) }
+
+impl From<&'static str> for A {
+    fn from(v: &'static str) -> Self {
+        Self::One(v)
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_add_from_impl_generic_enum() {
+        check_assist(
+            generate_from_impl_for_enum,
+            "enum Generic<T, U: Clone> { $0One(T), Two(U) }",
+            r#"enum Generic<T, U: Clone> { One(T), Two(U) }
+
+impl<T, U: Clone> From<T> for Generic<T, U> {
+    fn from(v: T) -> Self {
+        Self::One(v)
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_add_from_impl_with_lifetime() {
+        check_assist(
+            generate_from_impl_for_enum,
+            "enum Generic<'a> { $0One(&'a i32) }",
+            r#"enum Generic<'a> { One(&'a i32) }
+
+impl<'a> From<&'a i32> for Generic<'a> {
+    fn from(v: &'a i32) -> Self {
+        Self::One(v)
+    }
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_function.rs b/crates/ide_assists/src/handlers/generate_function.rs
new file mode 100644
index 000000000..959824981
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_function.rs
@@ -0,0 +1,1071 @@
+use hir::HirDisplay;
+use ide_db::{base_db::FileId, helpers::SnippetCap};
+use rustc_hash::{FxHashMap, FxHashSet};
+use syntax::{
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+        make, ArgListOwner, AstNode, ModuleItemOwner,
+    },
+    SyntaxKind, SyntaxNode, TextSize,
+};
+
+use crate::{
+    utils::{render_snippet, Cursor},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: generate_function
+//
+// Adds a stub function with a signature matching the function under the cursor.
+//
+// ```
+// struct Baz;
+// fn baz() -> Baz { Baz }
+// fn foo() {
+//     bar$0("", baz());
+// }
+//
+// ```
+// ->
+// ```
+// struct Baz;
+// fn baz() -> Baz { Baz }
+// fn foo() {
+//     bar("", baz());
+// }
+//
+// fn bar(arg: &str, baz: Baz) ${0:-> ()} {
+//     todo!()
+// }
+//
+// ```
+pub(crate) fn generate_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let path_expr: ast::PathExpr = ctx.find_node_at_offset()?;
+    let call = path_expr.syntax().parent().and_then(ast::CallExpr::cast)?;
+    let path = path_expr.path()?;
+
+    if ctx.sema.resolve_path(&path).is_some() {
+        // The function call already resolves, no need to add a function
+        return None;
+    }
+
+    let target_module = match path.qualifier() {
+        Some(qualifier) => match ctx.sema.resolve_path(&qualifier) {
+            Some(hir::PathResolution::Def(hir::ModuleDef::Module(module))) => Some(module),
+            _ => return None,
+        },
+        None => None,
+    };
+
+    let function_builder = FunctionBuilder::from_call(&ctx, &call, &path, target_module)?;
+
+    let target = call.syntax().text_range();
+    acc.add(
+        AssistId("generate_function", AssistKind::Generate),
+        format!("Generate `{}` function", function_builder.fn_name),
+        target,
+        |builder| {
+            let function_template = function_builder.render();
+            builder.edit_file(function_template.file);
+            let new_fn = function_template.to_string(ctx.config.snippet_cap);
+            match ctx.config.snippet_cap {
+                Some(cap) => builder.insert_snippet(cap, function_template.insert_offset, new_fn),
+                None => builder.insert(function_template.insert_offset, new_fn),
+            }
+        },
+    )
+}
+
+struct FunctionTemplate {
+    insert_offset: TextSize,
+    leading_ws: String,
+    fn_def: ast::Fn,
+    ret_type: ast::RetType,
+    trailing_ws: String,
+    file: FileId,
+}
+
+impl FunctionTemplate {
+    fn to_string(&self, cap: Option<SnippetCap>) -> String {
+        let f = match cap {
+            Some(cap) => {
+                render_snippet(cap, self.fn_def.syntax(), Cursor::Replace(self.ret_type.syntax()))
+            }
+            None => self.fn_def.to_string(),
+        };
+        format!("{}{}{}", self.leading_ws, f, self.trailing_ws)
+    }
+}
+
+struct FunctionBuilder {
+    target: GeneratedFunctionTarget,
+    fn_name: ast::Name,
+    type_params: Option<ast::GenericParamList>,
+    params: ast::ParamList,
+    file: FileId,
+    needs_pub: bool,
+}
+
+impl FunctionBuilder {
+    /// Prepares a generated function that matches `call`.
+    /// The function is generated in `target_module` or next to `call`
+    fn from_call(
+        ctx: &AssistContext,
+        call: &ast::CallExpr,
+        path: &ast::Path,
+        target_module: Option<hir::Module>,
+    ) -> Option<Self> {
+        let mut file = ctx.frange.file_id;
+        let target = match &target_module {
+            Some(target_module) => {
+                let module_source = target_module.definition_source(ctx.db());
+                let (in_file, target) = next_space_for_fn_in_module(ctx.sema.db, &module_source)?;
+                file = in_file;
+                target
+            }
+            None => next_space_for_fn_after_call_site(&call)?,
+        };
+        let needs_pub = target_module.is_some();
+        let target_module = target_module.or_else(|| ctx.sema.scope(target.syntax()).module())?;
+        let fn_name = fn_name(&path)?;
+        let (type_params, params) = fn_args(ctx, target_module, &call)?;
+
+        Some(Self { target, fn_name, type_params, params, file, needs_pub })
+    }
+
+    fn render(self) -> FunctionTemplate {
+        let placeholder_expr = make::expr_todo();
+        let fn_body = make::block_expr(vec![], Some(placeholder_expr));
+        let visibility = if self.needs_pub { Some(make::visibility_pub_crate()) } else { None };
+        let mut fn_def = make::fn_(
+            visibility,
+            self.fn_name,
+            self.type_params,
+            self.params,
+            fn_body,
+            Some(make::ret_type(make::ty_unit())),
+        );
+        let leading_ws;
+        let trailing_ws;
+
+        let insert_offset = match self.target {
+            GeneratedFunctionTarget::BehindItem(it) => {
+                let indent = IndentLevel::from_node(&it);
+                leading_ws = format!("\n\n{}", indent);
+                fn_def = fn_def.indent(indent);
+                trailing_ws = String::new();
+                it.text_range().end()
+            }
+            GeneratedFunctionTarget::InEmptyItemList(it) => {
+                let indent = IndentLevel::from_node(&it);
+                leading_ws = format!("\n{}", indent + 1);
+                fn_def = fn_def.indent(indent + 1);
+                trailing_ws = format!("\n{}", indent);
+                it.text_range().start() + TextSize::of('{')
+            }
+        };
+
+        FunctionTemplate {
+            insert_offset,
+            leading_ws,
+            ret_type: fn_def.ret_type().unwrap(),
+            fn_def,
+            trailing_ws,
+            file: self.file,
+        }
+    }
+}
+
+enum GeneratedFunctionTarget {
+    BehindItem(SyntaxNode),
+    InEmptyItemList(SyntaxNode),
+}
+
+impl GeneratedFunctionTarget {
+    fn syntax(&self) -> &SyntaxNode {
+        match self {
+            GeneratedFunctionTarget::BehindItem(it) => it,
+            GeneratedFunctionTarget::InEmptyItemList(it) => it,
+        }
+    }
+}
+
+fn fn_name(call: &ast::Path) -> Option<ast::Name> {
+    let name = call.segment()?.syntax().to_string();
+    Some(make::name(&name))
+}
+
+/// Computes the type variables and arguments required for the generated function
+fn fn_args(
+    ctx: &AssistContext,
+    target_module: hir::Module,
+    call: &ast::CallExpr,
+) -> Option<(Option<ast::GenericParamList>, ast::ParamList)> {
+    let mut arg_names = Vec::new();
+    let mut arg_types = Vec::new();
+    for arg in call.arg_list()?.args() {
+        arg_names.push(match fn_arg_name(&arg) {
+            Some(name) => name,
+            None => String::from("arg"),
+        });
+        arg_types.push(match fn_arg_type(ctx, target_module, &arg) {
+            Some(ty) => ty,
+            None => String::from("()"),
+        });
+    }
+    deduplicate_arg_names(&mut arg_names);
+    let params = arg_names
+        .into_iter()
+        .zip(arg_types)
+        .map(|(name, ty)| make::param(make::ident_pat(make::name(&name)).into(), make::ty(&ty)));
+    Some((None, make::param_list(None, params)))
+}
+
+/// Makes duplicate argument names unique by appending incrementing numbers.
+///
+/// ```
+/// let mut names: Vec<String> =
+///     vec!["foo".into(), "foo".into(), "bar".into(), "baz".into(), "bar".into()];
+/// deduplicate_arg_names(&mut names);
+/// let expected: Vec<String> =
+///     vec!["foo_1".into(), "foo_2".into(), "bar_1".into(), "baz".into(), "bar_2".into()];
+/// assert_eq!(names, expected);
+/// ```
+fn deduplicate_arg_names(arg_names: &mut Vec<String>) {
+    let arg_name_counts = arg_names.iter().fold(FxHashMap::default(), |mut m, name| {
+        *m.entry(name).or_insert(0) += 1;
+        m
+    });
+    let duplicate_arg_names: FxHashSet<String> = arg_name_counts
+        .into_iter()
+        .filter(|(_, count)| *count >= 2)
+        .map(|(name, _)| name.clone())
+        .collect();
+
+    let mut counter_per_name = FxHashMap::default();
+    for arg_name in arg_names.iter_mut() {
+        if duplicate_arg_names.contains(arg_name) {
+            let counter = counter_per_name.entry(arg_name.clone()).or_insert(1);
+            arg_name.push('_');
+            arg_name.push_str(&counter.to_string());
+            *counter += 1;
+        }
+    }
+}
+
+fn fn_arg_name(fn_arg: &ast::Expr) -> Option<String> {
+    match fn_arg {
+        ast::Expr::CastExpr(cast_expr) => fn_arg_name(&cast_expr.expr()?),
+        _ => Some(
+            fn_arg
+                .syntax()
+                .descendants()
+                .filter(|d| ast::NameRef::can_cast(d.kind()))
+                .last()?
+                .to_string(),
+        ),
+    }
+}
+
+fn fn_arg_type(
+    ctx: &AssistContext,
+    target_module: hir::Module,
+    fn_arg: &ast::Expr,
+) -> Option<String> {
+    let ty = ctx.sema.type_of_expr(fn_arg)?;
+    if ty.is_unknown() {
+        return None;
+    }
+
+    if let Ok(rendered) = ty.display_source_code(ctx.db(), target_module.into()) {
+        Some(rendered)
+    } else {
+        None
+    }
+}
+
+/// Returns the position inside the current mod or file
+/// directly after the current block
+/// We want to write the generated function directly after
+/// fns, impls or macro calls, but inside mods
+fn next_space_for_fn_after_call_site(expr: &ast::CallExpr) -> Option<GeneratedFunctionTarget> {
+    let mut ancestors = expr.syntax().ancestors().peekable();
+    let mut last_ancestor: Option<SyntaxNode> = None;
+    while let Some(next_ancestor) = ancestors.next() {
+        match next_ancestor.kind() {
+            SyntaxKind::SOURCE_FILE => {
+                break;
+            }
+            SyntaxKind::ITEM_LIST => {
+                if ancestors.peek().map(|a| a.kind()) == Some(SyntaxKind::MODULE) {
+                    break;
+                }
+            }
+            _ => {}
+        }
+        last_ancestor = Some(next_ancestor);
+    }
+    last_ancestor.map(GeneratedFunctionTarget::BehindItem)
+}
+
+fn next_space_for_fn_in_module(
+    db: &dyn hir::db::AstDatabase,
+    module_source: &hir::InFile<hir::ModuleSource>,
+) -> Option<(FileId, GeneratedFunctionTarget)> {
+    let file = module_source.file_id.original_file(db);
+    let assist_item = match &module_source.value {
+        hir::ModuleSource::SourceFile(it) => {
+            if let Some(last_item) = it.items().last() {
+                GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
+            } else {
+                GeneratedFunctionTarget::BehindItem(it.syntax().clone())
+            }
+        }
+        hir::ModuleSource::Module(it) => {
+            if let Some(last_item) = it.item_list().and_then(|it| it.items().last()) {
+                GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
+            } else {
+                GeneratedFunctionTarget::InEmptyItemList(it.item_list()?.syntax().clone())
+            }
+        }
+        hir::ModuleSource::BlockExpr(it) => {
+            if let Some(last_item) =
+                it.statements().take_while(|stmt| matches!(stmt, ast::Stmt::Item(_))).last()
+            {
+                GeneratedFunctionTarget::BehindItem(last_item.syntax().clone())
+            } else {
+                GeneratedFunctionTarget::InEmptyItemList(it.syntax().clone())
+            }
+        }
+    };
+    Some((file, assist_item))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn add_function_with_no_args() {
+        check_assist(
+            generate_function,
+            r"
+fn foo() {
+    bar$0();
+}
+",
+            r"
+fn foo() {
+    bar();
+}
+
+fn bar() ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_from_method() {
+        // This ensures that the function is correctly generated
+        // in the next outer mod or file
+        check_assist(
+            generate_function,
+            r"
+impl Foo {
+    fn foo() {
+        bar$0();
+    }
+}
+",
+            r"
+impl Foo {
+    fn foo() {
+        bar();
+    }
+}
+
+fn bar() ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_directly_after_current_block() {
+        // The new fn should not be created at the end of the file or module
+        check_assist(
+            generate_function,
+            r"
+fn foo1() {
+    bar$0();
+}
+
+fn foo2() {}
+",
+            r"
+fn foo1() {
+    bar();
+}
+
+fn bar() ${0:-> ()} {
+    todo!()
+}
+
+fn foo2() {}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_with_no_args_in_same_module() {
+        check_assist(
+            generate_function,
+            r"
+mod baz {
+    fn foo() {
+        bar$0();
+    }
+}
+",
+            r"
+mod baz {
+    fn foo() {
+        bar();
+    }
+
+    fn bar() ${0:-> ()} {
+        todo!()
+    }
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_with_function_call_arg() {
+        check_assist(
+            generate_function,
+            r"
+struct Baz;
+fn baz() -> Baz { todo!() }
+fn foo() {
+    bar$0(baz());
+}
+",
+            r"
+struct Baz;
+fn baz() -> Baz { todo!() }
+fn foo() {
+    bar(baz());
+}
+
+fn bar(baz: Baz) ${0:-> ()} {
+    todo!()
+}
+",
+        );
+    }
+
+    #[test]
+    fn add_function_with_method_call_arg() {
+        check_assist(
+            generate_function,
+            r"
+struct Baz;
+impl Baz {
+    fn foo(&self) -> Baz {
+        ba$0r(self.baz())
+    }
+    fn baz(&self) -> Baz {
+        Baz
+    }
+}
+",
+            r"
+struct Baz;
+impl Baz {
+    fn foo(&self) -> Baz {
+        bar(self.baz())
+    }
+    fn baz(&self) -> Baz {
+        Baz
+    }
+}
+
+fn bar(baz: Baz) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_with_string_literal_arg() {
+        check_assist(
+            generate_function,
+            r#"
+fn foo() {
+    $0bar("bar")
+}
+"#,
+            r#"
+fn foo() {
+    bar("bar")
+}
+
+fn bar(arg: &str) ${0:-> ()} {
+    todo!()
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn add_function_with_char_literal_arg() {
+        check_assist(
+            generate_function,
+            r#"
+fn foo() {
+    $0bar('x')
+}
+"#,
+            r#"
+fn foo() {
+    bar('x')
+}
+
+fn bar(arg: char) ${0:-> ()} {
+    todo!()
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn add_function_with_int_literal_arg() {
+        check_assist(
+            generate_function,
+            r"
+fn foo() {
+    $0bar(42)
+}
+",
+            r"
+fn foo() {
+    bar(42)
+}
+
+fn bar(arg: i32) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_with_cast_int_literal_arg() {
+        check_assist(
+            generate_function,
+            r"
+fn foo() {
+    $0bar(42 as u8)
+}
+",
+            r"
+fn foo() {
+    bar(42 as u8)
+}
+
+fn bar(arg: u8) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn name_of_cast_variable_is_used() {
+        // Ensures that the name of the cast type isn't used
+        // in the generated function signature.
+        check_assist(
+            generate_function,
+            r"
+fn foo() {
+    let x = 42;
+    bar$0(x as u8)
+}
+",
+            r"
+fn foo() {
+    let x = 42;
+    bar(x as u8)
+}
+
+fn bar(x: u8) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_with_variable_arg() {
+        check_assist(
+            generate_function,
+            r"
+fn foo() {
+    let worble = ();
+    $0bar(worble)
+}
+",
+            r"
+fn foo() {
+    let worble = ();
+    bar(worble)
+}
+
+fn bar(worble: ()) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_with_impl_trait_arg() {
+        check_assist(
+            generate_function,
+            r"
+trait Foo {}
+fn foo() -> impl Foo {
+    todo!()
+}
+fn baz() {
+    $0bar(foo())
+}
+",
+            r"
+trait Foo {}
+fn foo() -> impl Foo {
+    todo!()
+}
+fn baz() {
+    bar(foo())
+}
+
+fn bar(foo: impl Foo) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn borrowed_arg() {
+        check_assist(
+            generate_function,
+            r"
+struct Baz;
+fn baz() -> Baz { todo!() }
+
+fn foo() {
+    bar$0(&baz())
+}
+",
+            r"
+struct Baz;
+fn baz() -> Baz { todo!() }
+
+fn foo() {
+    bar(&baz())
+}
+
+fn bar(baz: &Baz) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_with_qualified_path_arg() {
+        check_assist(
+            generate_function,
+            r"
+mod Baz {
+    pub struct Bof;
+    pub fn baz() -> Bof { Bof }
+}
+fn foo() {
+    $0bar(Baz::baz())
+}
+",
+            r"
+mod Baz {
+    pub struct Bof;
+    pub fn baz() -> Bof { Bof }
+}
+fn foo() {
+    bar(Baz::baz())
+}
+
+fn bar(baz: Baz::Bof) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    #[ignore]
+    // FIXME fix printing the generics of a `Ty` to make this test pass
+    fn add_function_with_generic_arg() {
+        check_assist(
+            generate_function,
+            r"
+fn foo<T>(t: T) {
+    $0bar(t)
+}
+",
+            r"
+fn foo<T>(t: T) {
+    bar(t)
+}
+
+fn bar<T>(t: T) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    #[ignore]
+    // FIXME Fix function type printing to make this test pass
+    fn add_function_with_fn_arg() {
+        check_assist(
+            generate_function,
+            r"
+struct Baz;
+impl Baz {
+    fn new() -> Self { Baz }
+}
+fn foo() {
+    $0bar(Baz::new);
+}
+",
+            r"
+struct Baz;
+impl Baz {
+    fn new() -> Self { Baz }
+}
+fn foo() {
+    bar(Baz::new);
+}
+
+fn bar(arg: fn() -> Baz) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    #[ignore]
+    // FIXME Fix closure type printing to make this test pass
+    fn add_function_with_closure_arg() {
+        check_assist(
+            generate_function,
+            r"
+fn foo() {
+    let closure = |x: i64| x - 1;
+    $0bar(closure)
+}
+",
+            r"
+fn foo() {
+    let closure = |x: i64| x - 1;
+    bar(closure)
+}
+
+fn bar(closure: impl Fn(i64) -> i64) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn unresolveable_types_default_to_unit() {
+        check_assist(
+            generate_function,
+            r"
+fn foo() {
+    $0bar(baz)
+}
+",
+            r"
+fn foo() {
+    bar(baz)
+}
+
+fn bar(baz: ()) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn arg_names_dont_overlap() {
+        check_assist(
+            generate_function,
+            r"
+struct Baz;
+fn baz() -> Baz { Baz }
+fn foo() {
+    $0bar(baz(), baz())
+}
+",
+            r"
+struct Baz;
+fn baz() -> Baz { Baz }
+fn foo() {
+    bar(baz(), baz())
+}
+
+fn bar(baz_1: Baz, baz_2: Baz) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn arg_name_counters_start_at_1_per_name() {
+        check_assist(
+            generate_function,
+            r#"
+struct Baz;
+fn baz() -> Baz { Baz }
+fn foo() {
+    $0bar(baz(), baz(), "foo", "bar")
+}
+"#,
+            r#"
+struct Baz;
+fn baz() -> Baz { Baz }
+fn foo() {
+    bar(baz(), baz(), "foo", "bar")
+}
+
+fn bar(baz_1: Baz, baz_2: Baz, arg_1: &str, arg_2: &str) ${0:-> ()} {
+    todo!()
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn add_function_in_module() {
+        check_assist(
+            generate_function,
+            r"
+mod bar {}
+
+fn foo() {
+    bar::my_fn$0()
+}
+",
+            r"
+mod bar {
+    pub(crate) fn my_fn() ${0:-> ()} {
+        todo!()
+    }
+}
+
+fn foo() {
+    bar::my_fn()
+}
+",
+        )
+    }
+
+    #[test]
+    #[ignore]
+    // Ignored until local imports are supported.
+    // See https://github.com/rust-analyzer/rust-analyzer/issues/1165
+    fn qualified_path_uses_correct_scope() {
+        check_assist(
+            generate_function,
+            "
+mod foo {
+    pub struct Foo;
+}
+fn bar() {
+    use foo::Foo;
+    let foo = Foo;
+    baz$0(foo)
+}
+",
+            "
+mod foo {
+    pub struct Foo;
+}
+fn bar() {
+    use foo::Foo;
+    let foo = Foo;
+    baz(foo)
+}
+
+fn baz(foo: foo::Foo) ${0:-> ()} {
+    todo!()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_in_module_containing_other_items() {
+        check_assist(
+            generate_function,
+            r"
+mod bar {
+    fn something_else() {}
+}
+
+fn foo() {
+    bar::my_fn$0()
+}
+",
+            r"
+mod bar {
+    fn something_else() {}
+
+    pub(crate) fn my_fn() ${0:-> ()} {
+        todo!()
+    }
+}
+
+fn foo() {
+    bar::my_fn()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_in_nested_module() {
+        check_assist(
+            generate_function,
+            r"
+mod bar {
+    mod baz {}
+}
+
+fn foo() {
+    bar::baz::my_fn$0()
+}
+",
+            r"
+mod bar {
+    mod baz {
+        pub(crate) fn my_fn() ${0:-> ()} {
+            todo!()
+        }
+    }
+}
+
+fn foo() {
+    bar::baz::my_fn()
+}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_in_another_file() {
+        check_assist(
+            generate_function,
+            r"
+//- /main.rs
+mod foo;
+
+fn main() {
+    foo::bar$0()
+}
+//- /foo.rs
+",
+            r"
+
+
+pub(crate) fn bar() ${0:-> ()} {
+    todo!()
+}",
+        )
+    }
+
+    #[test]
+    fn add_function_not_applicable_if_function_already_exists() {
+        check_assist_not_applicable(
+            generate_function,
+            r"
+fn foo() {
+    bar$0();
+}
+
+fn bar() {}
+",
+        )
+    }
+
+    #[test]
+    fn add_function_not_applicable_if_unresolved_variable_in_call_is_selected() {
+        check_assist_not_applicable(
+            // bar is resolved, but baz isn't.
+            // The assist is only active if the cursor is on an unresolved path,
+            // but the assist should only be offered if the path is a function call.
+            generate_function,
+            r"
+fn foo() {
+    bar(b$0az);
+}
+
+fn bar(baz: ()) {}
+",
+        )
+    }
+
+    #[test]
+    #[ignore]
+    fn create_method_with_no_args() {
+        check_assist(
+            generate_function,
+            r"
+struct Foo;
+impl Foo {
+    fn foo(&self) {
+        self.bar()$0;
+    }
+}
+        ",
+            r"
+struct Foo;
+impl Foo {
+    fn foo(&self) {
+        self.bar();
+    }
+    fn bar(&self) {
+        todo!();
+    }
+}
+        ",
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_getter.rs b/crates/ide_assists/src/handlers/generate_getter.rs
new file mode 100644
index 000000000..df7d1bb95
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_getter.rs
@@ -0,0 +1,192 @@
+use stdx::{format_to, to_lower_snake_case};
+use syntax::ast::{self, AstNode, NameOwner, VisibilityOwner};
+
+use crate::{
+    utils::{find_impl_block_end, find_struct_impl, generate_impl_text},
+    AssistContext, AssistId, AssistKind, Assists, GroupLabel,
+};
+
+// Assist: generate_getter
+//
+// Generate a getter method.
+//
+// ```
+// struct Person {
+//     nam$0e: String,
+// }
+// ```
+// ->
+// ```
+// struct Person {
+//     name: String,
+// }
+//
+// impl Person {
+//     /// Get a reference to the person's name.
+//     fn name(&self) -> &String {
+//         &self.name
+//     }
+// }
+// ```
+pub(crate) fn generate_getter(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
+    let field = ctx.find_node_at_offset::<ast::RecordField>()?;
+
+    let strukt_name = strukt.name()?;
+    let field_name = field.name()?;
+    let field_ty = field.ty()?;
+
+    // Return early if we've found an existing fn
+    let fn_name = to_lower_snake_case(&field_name.to_string());
+    let impl_def = find_struct_impl(&ctx, &ast::Adt::Struct(strukt.clone()), fn_name.as_str())?;
+
+    let target = field.syntax().text_range();
+    acc.add_group(
+        &GroupLabel("Generate getter/setter".to_owned()),
+        AssistId("generate_getter", AssistKind::Generate),
+        "Generate a getter method",
+        target,
+        |builder| {
+            let mut buf = String::with_capacity(512);
+
+            let fn_name_spaced = fn_name.replace('_', " ");
+            let strukt_name_spaced =
+                to_lower_snake_case(&strukt_name.to_string()).replace('_', " ");
+
+            if impl_def.is_some() {
+                buf.push('\n');
+            }
+
+            let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
+            format_to!(
+                buf,
+                "    /// Get a reference to the {}'s {}.
+    {}fn {}(&self) -> &{} {{
+        &self.{}
+    }}",
+                strukt_name_spaced,
+                fn_name_spaced,
+                vis,
+                fn_name,
+                field_ty,
+                fn_name,
+            );
+
+            let start_offset = impl_def
+                .and_then(|impl_def| find_impl_block_end(impl_def, &mut buf))
+                .unwrap_or_else(|| {
+                    buf = generate_impl_text(&ast::Adt::Struct(strukt.clone()), &buf);
+                    strukt.syntax().text_range().end()
+                });
+
+            builder.insert(start_offset, buf);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    fn check_not_applicable(ra_fixture: &str) {
+        check_assist_not_applicable(generate_getter, ra_fixture)
+    }
+
+    #[test]
+    fn test_generate_getter_from_field() {
+        check_assist(
+            generate_getter,
+            r#"
+struct Context<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a reference to the context's data.
+    fn data(&self) -> &T {
+        &self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_getter_already_implemented() {
+        check_not_applicable(
+            r#"
+struct Context<T: Clone> {
+    dat$0a: T,
+}
+
+impl<T: Clone> Context<T> {
+    fn data(&self) -> &T {
+        &self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_getter_from_field_with_visibility_marker() {
+        check_assist(
+            generate_getter,
+            r#"
+pub(crate) struct Context<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+pub(crate) struct Context<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a reference to the context's data.
+    pub(crate) fn data(&self) -> &T {
+        &self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_multiple_generate_getter() {
+        check_assist(
+            generate_getter,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+    cou$0nt: usize,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a reference to the context's data.
+    fn data(&self) -> &T {
+        &self.data
+    }
+}"#,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+    count: usize,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a reference to the context's data.
+    fn data(&self) -> &T {
+        &self.data
+    }
+
+    /// Get a reference to the context's count.
+    fn count(&self) -> &usize {
+        &self.count
+    }
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_getter_mut.rs b/crates/ide_assists/src/handlers/generate_getter_mut.rs
new file mode 100644
index 000000000..821c2eed5
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_getter_mut.rs
@@ -0,0 +1,195 @@
+use stdx::{format_to, to_lower_snake_case};
+use syntax::ast::{self, AstNode, NameOwner, VisibilityOwner};
+
+use crate::{
+    utils::{find_impl_block_end, find_struct_impl, generate_impl_text},
+    AssistContext, AssistId, AssistKind, Assists, GroupLabel,
+};
+
+// Assist: generate_getter_mut
+//
+// Generate a mut getter method.
+//
+// ```
+// struct Person {
+//     nam$0e: String,
+// }
+// ```
+// ->
+// ```
+// struct Person {
+//     name: String,
+// }
+//
+// impl Person {
+//     /// Get a mutable reference to the person's name.
+//     fn name_mut(&mut self) -> &mut String {
+//         &mut self.name
+//     }
+// }
+// ```
+pub(crate) fn generate_getter_mut(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
+    let field = ctx.find_node_at_offset::<ast::RecordField>()?;
+
+    let strukt_name = strukt.name()?;
+    let field_name = field.name()?;
+    let field_ty = field.ty()?;
+
+    // Return early if we've found an existing fn
+    let fn_name = to_lower_snake_case(&field_name.to_string());
+    let impl_def = find_struct_impl(
+        &ctx,
+        &ast::Adt::Struct(strukt.clone()),
+        format!("{}_mut", fn_name).as_str(),
+    )?;
+
+    let target = field.syntax().text_range();
+    acc.add_group(
+        &GroupLabel("Generate getter/setter".to_owned()),
+        AssistId("generate_getter_mut", AssistKind::Generate),
+        "Generate a mut getter method",
+        target,
+        |builder| {
+            let mut buf = String::with_capacity(512);
+            let fn_name_spaced = fn_name.replace('_', " ");
+            let strukt_name_spaced =
+                to_lower_snake_case(&strukt_name.to_string()).replace('_', " ");
+
+            if impl_def.is_some() {
+                buf.push('\n');
+            }
+
+            let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
+            format_to!(
+                buf,
+                "    /// Get a mutable reference to the {}'s {}.
+    {}fn {}_mut(&mut self) -> &mut {} {{
+        &mut self.{}
+    }}",
+                strukt_name_spaced,
+                fn_name_spaced,
+                vis,
+                fn_name,
+                field_ty,
+                fn_name,
+            );
+
+            let start_offset = impl_def
+                .and_then(|impl_def| find_impl_block_end(impl_def, &mut buf))
+                .unwrap_or_else(|| {
+                    buf = generate_impl_text(&ast::Adt::Struct(strukt.clone()), &buf);
+                    strukt.syntax().text_range().end()
+                });
+
+            builder.insert(start_offset, buf);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    fn check_not_applicable(ra_fixture: &str) {
+        check_assist_not_applicable(generate_getter_mut, ra_fixture)
+    }
+
+    #[test]
+    fn test_generate_getter_mut_from_field() {
+        check_assist(
+            generate_getter_mut,
+            r#"
+struct Context<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a mutable reference to the context's data.
+    fn data_mut(&mut self) -> &mut T {
+        &mut self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_getter_mut_already_implemented() {
+        check_not_applicable(
+            r#"
+struct Context<T: Clone> {
+    dat$0a: T,
+}
+
+impl<T: Clone> Context<T> {
+    fn data_mut(&mut self) -> &mut T {
+        &mut self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_getter_mut_from_field_with_visibility_marker() {
+        check_assist(
+            generate_getter_mut,
+            r#"
+pub(crate) struct Context<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+pub(crate) struct Context<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a mutable reference to the context's data.
+    pub(crate) fn data_mut(&mut self) -> &mut T {
+        &mut self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_multiple_generate_getter_mut() {
+        check_assist(
+            generate_getter_mut,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+    cou$0nt: usize,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a mutable reference to the context's data.
+    fn data_mut(&mut self) -> &mut T {
+        &mut self.data
+    }
+}"#,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+    count: usize,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a mutable reference to the context's data.
+    fn data_mut(&mut self) -> &mut T {
+        &mut self.data
+    }
+
+    /// Get a mutable reference to the context's count.
+    fn count_mut(&mut self) -> &mut usize {
+        &mut self.count
+    }
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_impl.rs b/crates/ide_assists/src/handlers/generate_impl.rs
new file mode 100644
index 000000000..a8e3c4fc2
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_impl.rs
@@ -0,0 +1,166 @@
+use syntax::ast::{self, AstNode, NameOwner};
+
+use crate::{utils::generate_impl_text, AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: generate_impl
+//
+// Adds a new inherent impl for a type.
+//
+// ```
+// struct Ctx<T: Clone> {
+//     data: T,$0
+// }
+// ```
+// ->
+// ```
+// struct Ctx<T: Clone> {
+//     data: T,
+// }
+//
+// impl<T: Clone> Ctx<T> {
+//     $0
+// }
+// ```
+pub(crate) fn generate_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let nominal = ctx.find_node_at_offset::<ast::Adt>()?;
+    let name = nominal.name()?;
+    let target = nominal.syntax().text_range();
+
+    acc.add(
+        AssistId("generate_impl", AssistKind::Generate),
+        format!("Generate impl for `{}`", name),
+        target,
+        |edit| {
+            let start_offset = nominal.syntax().text_range().end();
+            match ctx.config.snippet_cap {
+                Some(cap) => {
+                    let snippet = generate_impl_text(&nominal, "    $0");
+                    edit.insert_snippet(cap, start_offset, snippet);
+                }
+                None => {
+                    let snippet = generate_impl_text(&nominal, "");
+                    edit.insert(start_offset, snippet);
+                }
+            }
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn test_add_impl() {
+        check_assist(
+            generate_impl,
+            "struct Foo {$0}\n",
+            "struct Foo {}\n\nimpl Foo {\n    $0\n}\n",
+        );
+        check_assist(
+            generate_impl,
+            "struct Foo<T: Clone> {$0}",
+            "struct Foo<T: Clone> {}\n\nimpl<T: Clone> Foo<T> {\n    $0\n}",
+        );
+        check_assist(
+            generate_impl,
+            "struct Foo<'a, T: Foo<'a>> {$0}",
+            "struct Foo<'a, T: Foo<'a>> {}\n\nimpl<'a, T: Foo<'a>> Foo<'a, T> {\n    $0\n}",
+        );
+        check_assist(
+            generate_impl,
+            r#"
+            #[cfg(feature = "foo")]
+            struct Foo<'a, T: Foo<'a>> {$0}"#,
+            r#"
+            #[cfg(feature = "foo")]
+            struct Foo<'a, T: Foo<'a>> {}
+
+            #[cfg(feature = "foo")]
+            impl<'a, T: Foo<'a>> Foo<'a, T> {
+                $0
+            }"#,
+        );
+
+        check_assist(
+            generate_impl,
+            r#"
+            #[cfg(not(feature = "foo"))]
+            struct Foo<'a, T: Foo<'a>> {$0}"#,
+            r#"
+            #[cfg(not(feature = "foo"))]
+            struct Foo<'a, T: Foo<'a>> {}
+
+            #[cfg(not(feature = "foo"))]
+            impl<'a, T: Foo<'a>> Foo<'a, T> {
+                $0
+            }"#,
+        );
+
+        check_assist(
+            generate_impl,
+            r#"
+            struct Defaulted<T = i32> {}$0"#,
+            r#"
+            struct Defaulted<T = i32> {}
+
+            impl<T> Defaulted<T> {
+                $0
+            }"#,
+        );
+
+        check_assist(
+            generate_impl,
+            r#"
+            struct Defaulted<'a, 'b: 'a, T: Debug + Clone + 'a + 'b = String> {}$0"#,
+            r#"
+            struct Defaulted<'a, 'b: 'a, T: Debug + Clone + 'a + 'b = String> {}
+
+            impl<'a, 'b: 'a, T: Debug + Clone + 'a + 'b> Defaulted<'a, 'b, T> {
+                $0
+            }"#,
+        );
+
+        check_assist(
+            generate_impl,
+            r#"pub trait Trait {}
+struct Struct<T>$0
+where
+    T: Trait,
+{
+    inner: T,
+}"#,
+            r#"pub trait Trait {}
+struct Struct<T>
+where
+    T: Trait,
+{
+    inner: T,
+}
+
+impl<T> Struct<T>
+where
+    T: Trait,
+{
+    $0
+}"#,
+        );
+    }
+
+    #[test]
+    fn add_impl_target() {
+        check_assist_target(
+            generate_impl,
+            "
+struct SomeThingIrrelevant;
+/// Has a lifetime parameter
+struct Foo<'a, T: Foo<'a>> {$0}
+struct EvenMoreIrrelevant;
+",
+            "/// Has a lifetime parameter
+struct Foo<'a, T: Foo<'a>> {}",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_new.rs b/crates/ide_assists/src/handlers/generate_new.rs
new file mode 100644
index 000000000..8ce5930b7
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_new.rs
@@ -0,0 +1,315 @@
+use ast::Adt;
+use itertools::Itertools;
+use stdx::format_to;
+use syntax::ast::{self, AstNode, NameOwner, StructKind, VisibilityOwner};
+
+use crate::{
+    utils::{find_impl_block_start, find_struct_impl, generate_impl_text},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: generate_new
+//
+// Adds a new inherent impl for a type.
+//
+// ```
+// struct Ctx<T: Clone> {
+//      data: T,$0
+// }
+// ```
+// ->
+// ```
+// struct Ctx<T: Clone> {
+//      data: T,
+// }
+//
+// impl<T: Clone> Ctx<T> {
+//     fn $0new(data: T) -> Self { Self { data } }
+// }
+// ```
+pub(crate) fn generate_new(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
+
+    // We want to only apply this to non-union structs with named fields
+    let field_list = match strukt.kind() {
+        StructKind::Record(named) => named,
+        _ => return None,
+    };
+
+    // Return early if we've found an existing new fn
+    let impl_def = find_struct_impl(&ctx, &Adt::Struct(strukt.clone()), "new")?;
+
+    let target = strukt.syntax().text_range();
+    acc.add(AssistId("generate_new", AssistKind::Generate), "Generate `new`", target, |builder| {
+        let mut buf = String::with_capacity(512);
+
+        if impl_def.is_some() {
+            buf.push('\n');
+        }
+
+        let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
+
+        let params = field_list
+            .fields()
+            .filter_map(|f| Some(format!("{}: {}", f.name()?.syntax(), f.ty()?.syntax())))
+            .format(", ");
+        let fields = field_list.fields().filter_map(|f| f.name()).format(", ");
+
+        format_to!(buf, "    {}fn new({}) -> Self {{ Self {{ {} }} }}", vis, params, fields);
+
+        let start_offset = impl_def
+            .and_then(|impl_def| find_impl_block_start(impl_def, &mut buf))
+            .unwrap_or_else(|| {
+                buf = generate_impl_text(&Adt::Struct(strukt.clone()), &buf);
+                strukt.syntax().text_range().end()
+            });
+
+        match ctx.config.snippet_cap {
+            None => builder.insert(start_offset, buf),
+            Some(cap) => {
+                buf = buf.replace("fn new", "fn $0new");
+                builder.insert_snippet(cap, start_offset, buf);
+            }
+        }
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    #[rustfmt::skip]
+    fn test_generate_new() {
+        // Check output of generation
+        check_assist(
+            generate_new,
+"struct Foo {$0}",
+"struct Foo {}
+
+impl Foo {
+    fn $0new() -> Self { Self {  } }
+}",
+        );
+        check_assist(
+            generate_new,
+"struct Foo<T: Clone> {$0}",
+"struct Foo<T: Clone> {}
+
+impl<T: Clone> Foo<T> {
+    fn $0new() -> Self { Self {  } }
+}",
+        );
+        check_assist(
+            generate_new,
+"struct Foo<'a, T: Foo<'a>> {$0}",
+"struct Foo<'a, T: Foo<'a>> {}
+
+impl<'a, T: Foo<'a>> Foo<'a, T> {
+    fn $0new() -> Self { Self {  } }
+}",
+        );
+        check_assist(
+            generate_new,
+"struct Foo { baz: String $0}",
+"struct Foo { baz: String }
+
+impl Foo {
+    fn $0new(baz: String) -> Self { Self { baz } }
+}",
+        );
+        check_assist(
+            generate_new,
+"struct Foo { baz: String, qux: Vec<i32> $0}",
+"struct Foo { baz: String, qux: Vec<i32> }
+
+impl Foo {
+    fn $0new(baz: String, qux: Vec<i32>) -> Self { Self { baz, qux } }
+}",
+        );
+
+        // Check that visibility modifiers don't get brought in for fields
+        check_assist(
+            generate_new,
+"struct Foo { pub baz: String, pub qux: Vec<i32> $0}",
+"struct Foo { pub baz: String, pub qux: Vec<i32> }
+
+impl Foo {
+    fn $0new(baz: String, qux: Vec<i32>) -> Self { Self { baz, qux } }
+}",
+        );
+
+        // Check that it reuses existing impls
+        check_assist(
+            generate_new,
+"struct Foo {$0}
+
+impl Foo {}
+",
+"struct Foo {}
+
+impl Foo {
+    fn $0new() -> Self { Self {  } }
+}
+",
+        );
+        check_assist(
+            generate_new,
+"struct Foo {$0}
+
+impl Foo {
+    fn qux(&self) {}
+}
+",
+"struct Foo {}
+
+impl Foo {
+    fn $0new() -> Self { Self {  } }
+
+    fn qux(&self) {}
+}
+",
+        );
+
+        check_assist(
+            generate_new,
+"struct Foo {$0}
+
+impl Foo {
+    fn qux(&self) {}
+    fn baz() -> i32 {
+        5
+    }
+}
+",
+"struct Foo {}
+
+impl Foo {
+    fn $0new() -> Self { Self {  } }
+
+    fn qux(&self) {}
+    fn baz() -> i32 {
+        5
+    }
+}
+",
+        );
+
+        // Check visibility of new fn based on struct
+        check_assist(
+            generate_new,
+"pub struct Foo {$0}",
+"pub struct Foo {}
+
+impl Foo {
+    pub fn $0new() -> Self { Self {  } }
+}",
+        );
+        check_assist(
+            generate_new,
+"pub(crate) struct Foo {$0}",
+"pub(crate) struct Foo {}
+
+impl Foo {
+    pub(crate) fn $0new() -> Self { Self {  } }
+}",
+        );
+    }
+
+    #[test]
+    fn generate_new_not_applicable_if_fn_exists() {
+        check_assist_not_applicable(
+            generate_new,
+            "
+struct Foo {$0}
+
+impl Foo {
+    fn new() -> Self {
+        Self
+    }
+}",
+        );
+
+        check_assist_not_applicable(
+            generate_new,
+            "
+struct Foo {$0}
+
+impl Foo {
+    fn New() -> Self {
+        Self
+    }
+}",
+        );
+    }
+
+    #[test]
+    fn generate_new_target() {
+        check_assist_target(
+            generate_new,
+            "
+struct SomeThingIrrelevant;
+/// Has a lifetime parameter
+struct Foo<'a, T: Foo<'a>> {$0}
+struct EvenMoreIrrelevant;
+",
+            "/// Has a lifetime parameter
+struct Foo<'a, T: Foo<'a>> {}",
+        );
+    }
+
+    #[test]
+    fn test_unrelated_new() {
+        check_assist(
+            generate_new,
+            r##"
+pub struct AstId<N: AstNode> {
+    file_id: HirFileId,
+    file_ast_id: FileAstId<N>,
+}
+
+impl<N: AstNode> AstId<N> {
+    pub fn new(file_id: HirFileId, file_ast_id: FileAstId<N>) -> AstId<N> {
+        AstId { file_id, file_ast_id }
+    }
+}
+
+pub struct Source<T> {
+    pub file_id: HirFileId,$0
+    pub ast: T,
+}
+
+impl<T> Source<T> {
+    pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> Source<U> {
+        Source { file_id: self.file_id, ast: f(self.ast) }
+    }
+}"##,
+            r##"
+pub struct AstId<N: AstNode> {
+    file_id: HirFileId,
+    file_ast_id: FileAstId<N>,
+}
+
+impl<N: AstNode> AstId<N> {
+    pub fn new(file_id: HirFileId, file_ast_id: FileAstId<N>) -> AstId<N> {
+        AstId { file_id, file_ast_id }
+    }
+}
+
+pub struct Source<T> {
+    pub file_id: HirFileId,
+    pub ast: T,
+}
+
+impl<T> Source<T> {
+    pub fn $0new(file_id: HirFileId, ast: T) -> Self { Self { file_id, ast } }
+
+    pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> Source<U> {
+        Source { file_id: self.file_id, ast: f(self.ast) }
+    }
+}"##,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/generate_setter.rs b/crates/ide_assists/src/handlers/generate_setter.rs
new file mode 100644
index 000000000..288cf745d
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_setter.rs
@@ -0,0 +1,198 @@
+use stdx::{format_to, to_lower_snake_case};
+use syntax::ast::{self, AstNode, NameOwner, VisibilityOwner};
+
+use crate::{
+    utils::{find_impl_block_end, find_struct_impl, generate_impl_text},
+    AssistContext, AssistId, AssistKind, Assists, GroupLabel,
+};
+
+// Assist: generate_setter
+//
+// Generate a setter method.
+//
+// ```
+// struct Person {
+//     nam$0e: String,
+// }
+// ```
+// ->
+// ```
+// struct Person {
+//     name: String,
+// }
+//
+// impl Person {
+//     /// Set the person's name.
+//     fn set_name(&mut self, name: String) {
+//         self.name = name;
+//     }
+// }
+// ```
+pub(crate) fn generate_setter(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
+    let field = ctx.find_node_at_offset::<ast::RecordField>()?;
+
+    let strukt_name = strukt.name()?;
+    let field_name = field.name()?;
+    let field_ty = field.ty()?;
+
+    // Return early if we've found an existing fn
+    let fn_name = to_lower_snake_case(&field_name.to_string());
+    let impl_def = find_struct_impl(
+        &ctx,
+        &ast::Adt::Struct(strukt.clone()),
+        format!("set_{}", fn_name).as_str(),
+    )?;
+
+    let target = field.syntax().text_range();
+    acc.add_group(
+        &GroupLabel("Generate getter/setter".to_owned()),
+        AssistId("generate_setter", AssistKind::Generate),
+        "Generate a setter method",
+        target,
+        |builder| {
+            let mut buf = String::with_capacity(512);
+
+            let fn_name_spaced = fn_name.replace('_', " ");
+            let strukt_name_spaced =
+                to_lower_snake_case(&strukt_name.to_string()).replace('_', " ");
+
+            if impl_def.is_some() {
+                buf.push('\n');
+            }
+
+            let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
+            format_to!(
+                buf,
+                "    /// Set the {}'s {}.
+    {}fn set_{}(&mut self, {}: {}) {{
+        self.{} = {};
+    }}",
+                strukt_name_spaced,
+                fn_name_spaced,
+                vis,
+                fn_name,
+                fn_name,
+                field_ty,
+                fn_name,
+                fn_name,
+            );
+
+            let start_offset = impl_def
+                .and_then(|impl_def| find_impl_block_end(impl_def, &mut buf))
+                .unwrap_or_else(|| {
+                    buf = generate_impl_text(&ast::Adt::Struct(strukt.clone()), &buf);
+                    strukt.syntax().text_range().end()
+                });
+
+            builder.insert(start_offset, buf);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    fn check_not_applicable(ra_fixture: &str) {
+        check_assist_not_applicable(generate_setter, ra_fixture)
+    }
+
+    #[test]
+    fn test_generate_setter_from_field() {
+        check_assist(
+            generate_setter,
+            r#"
+struct Person<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+struct Person<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Person<T> {
+    /// Set the person's data.
+    fn set_data(&mut self, data: T) {
+        self.data = data;
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_setter_already_implemented() {
+        check_not_applicable(
+            r#"
+struct Person<T: Clone> {
+    dat$0a: T,
+}
+
+impl<T: Clone> Person<T> {
+    fn set_data(&mut self, data: T) {
+        self.data = data;
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_setter_from_field_with_visibility_marker() {
+        check_assist(
+            generate_setter,
+            r#"
+pub(crate) struct Person<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+pub(crate) struct Person<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Person<T> {
+    /// Set the person's data.
+    pub(crate) fn set_data(&mut self, data: T) {
+        self.data = data;
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_multiple_generate_setter() {
+        check_assist(
+            generate_setter,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+    cou$0nt: usize,
+}
+
+impl<T: Clone> Context<T> {
+    /// Set the context's data.
+    fn set_data(&mut self, data: T) {
+        self.data = data;
+    }
+}"#,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+    count: usize,
+}
+
+impl<T: Clone> Context<T> {
+    /// Set the context's data.
+    fn set_data(&mut self, data: T) {
+        self.data = data;
+    }
+
+    /// Set the context's count.
+    fn set_count(&mut self, count: usize) {
+        self.count = count;
+    }
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/infer_function_return_type.rs b/crates/ide_assists/src/handlers/infer_function_return_type.rs
new file mode 100644
index 000000000..5279af1f3
--- /dev/null
+++ b/crates/ide_assists/src/handlers/infer_function_return_type.rs
@@ -0,0 +1,345 @@
+use hir::HirDisplay;
+use syntax::{ast, AstNode, TextRange, TextSize};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: infer_function_return_type
+//
+// Adds the return type to a function or closure inferred from its tail expression if it doesn't have a return
+// type specified. This assists is useable in a functions or closures tail expression or return type position.
+//
+// ```
+// fn foo() { 4$02i32 }
+// ```
+// ->
+// ```
+// fn foo() -> i32 { 42i32 }
+// ```
+pub(crate) fn infer_function_return_type(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let (fn_type, tail_expr, builder_edit_pos) = extract_tail(ctx)?;
+    let module = ctx.sema.scope(tail_expr.syntax()).module()?;
+    let ty = ctx.sema.type_of_expr(&tail_expr)?;
+    if ty.is_unit() {
+        return None;
+    }
+    let ty = ty.display_source_code(ctx.db(), module.into()).ok()?;
+
+    acc.add(
+        AssistId("infer_function_return_type", AssistKind::RefactorRewrite),
+        match fn_type {
+            FnType::Function => "Add this function's return type",
+            FnType::Closure { .. } => "Add this closure's return type",
+        },
+        tail_expr.syntax().text_range(),
+        |builder| {
+            match builder_edit_pos {
+                InsertOrReplace::Insert(insert_pos) => {
+                    builder.insert(insert_pos, &format!("-> {} ", ty))
+                }
+                InsertOrReplace::Replace(text_range) => {
+                    builder.replace(text_range, &format!("-> {}", ty))
+                }
+            }
+            if let FnType::Closure { wrap_expr: true } = fn_type {
+                mark::hit!(wrap_closure_non_block_expr);
+                // `|x| x` becomes `|x| -> T x` which is invalid, so wrap it in a block
+                builder.replace(tail_expr.syntax().text_range(), &format!("{{{}}}", tail_expr));
+            }
+        },
+    )
+}
+
+enum InsertOrReplace {
+    Insert(TextSize),
+    Replace(TextRange),
+}
+
+/// Check the potentially already specified return type and reject it or turn it into a builder command
+/// if allowed.
+fn ret_ty_to_action(ret_ty: Option<ast::RetType>, insert_pos: TextSize) -> Option<InsertOrReplace> {
+    match ret_ty {
+        Some(ret_ty) => match ret_ty.ty() {
+            Some(ast::Type::InferType(_)) | None => {
+                mark::hit!(existing_infer_ret_type);
+                mark::hit!(existing_infer_ret_type_closure);
+                Some(InsertOrReplace::Replace(ret_ty.syntax().text_range()))
+            }
+            _ => {
+                mark::hit!(existing_ret_type);
+                mark::hit!(existing_ret_type_closure);
+                None
+            }
+        },
+        None => Some(InsertOrReplace::Insert(insert_pos + TextSize::from(1))),
+    }
+}
+
+enum FnType {
+    Function,
+    Closure { wrap_expr: bool },
+}
+
+fn extract_tail(ctx: &AssistContext) -> Option<(FnType, ast::Expr, InsertOrReplace)> {
+    let (fn_type, tail_expr, return_type_range, action) =
+        if let Some(closure) = ctx.find_node_at_offset::<ast::ClosureExpr>() {
+            let rpipe_pos = closure.param_list()?.syntax().last_token()?.text_range().end();
+            let action = ret_ty_to_action(closure.ret_type(), rpipe_pos)?;
+
+            let body = closure.body()?;
+            let body_start = body.syntax().first_token()?.text_range().start();
+            let (tail_expr, wrap_expr) = match body {
+                ast::Expr::BlockExpr(block) => (block.tail_expr()?, false),
+                body => (body, true),
+            };
+
+            let ret_range = TextRange::new(rpipe_pos, body_start);
+            (FnType::Closure { wrap_expr }, tail_expr, ret_range, action)
+        } else {
+            let func = ctx.find_node_at_offset::<ast::Fn>()?;
+            let rparen_pos = func.param_list()?.r_paren_token()?.text_range().end();
+            let action = ret_ty_to_action(func.ret_type(), rparen_pos)?;
+
+            let body = func.body()?;
+            let tail_expr = body.tail_expr()?;
+
+            let ret_range_end = body.l_curly_token()?.text_range().start();
+            let ret_range = TextRange::new(rparen_pos, ret_range_end);
+            (FnType::Function, tail_expr, ret_range, action)
+        };
+    let frange = ctx.frange.range;
+    if return_type_range.contains_range(frange) {
+        mark::hit!(cursor_in_ret_position);
+        mark::hit!(cursor_in_ret_position_closure);
+    } else if tail_expr.syntax().text_range().contains_range(frange) {
+        mark::hit!(cursor_on_tail);
+        mark::hit!(cursor_on_tail_closure);
+    } else {
+        return None;
+    }
+    Some((fn_type, tail_expr, action))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn infer_return_type_specified_inferred() {
+        mark::check!(existing_infer_ret_type);
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() -> $0_ {
+    45
+}"#,
+            r#"fn foo() -> i32 {
+    45
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type_specified_inferred_closure() {
+        mark::check!(existing_infer_ret_type_closure);
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() {
+    || -> _ {$045};
+}"#,
+            r#"fn foo() {
+    || -> i32 {45};
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type_cursor_at_return_type_pos() {
+        mark::check!(cursor_in_ret_position);
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() $0{
+    45
+}"#,
+            r#"fn foo() -> i32 {
+    45
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type_cursor_at_return_type_pos_closure() {
+        mark::check!(cursor_in_ret_position_closure);
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() {
+    || $045
+}"#,
+            r#"fn foo() {
+    || -> i32 {45}
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type() {
+        mark::check!(cursor_on_tail);
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() {
+    45$0
+}"#,
+            r#"fn foo() -> i32 {
+    45
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type_nested() {
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() {
+    if true {
+        3$0
+    } else {
+        5
+    }
+}"#,
+            r#"fn foo() -> i32 {
+    if true {
+        3
+    } else {
+        5
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn not_applicable_ret_type_specified() {
+        mark::check!(existing_ret_type);
+        check_assist_not_applicable(
+            infer_function_return_type,
+            r#"fn foo() -> i32 {
+    ( 45$0 + 32 ) * 123
+}"#,
+        );
+    }
+
+    #[test]
+    fn not_applicable_non_tail_expr() {
+        check_assist_not_applicable(
+            infer_function_return_type,
+            r#"fn foo() {
+    let x = $03;
+    ( 45 + 32 ) * 123
+}"#,
+        );
+    }
+
+    #[test]
+    fn not_applicable_unit_return_type() {
+        check_assist_not_applicable(
+            infer_function_return_type,
+            r#"fn foo() {
+    ($0)
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type_closure_block() {
+        mark::check!(cursor_on_tail_closure);
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() {
+    |x: i32| {
+        x$0
+    };
+}"#,
+            r#"fn foo() {
+    |x: i32| -> i32 {
+        x
+    };
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type_closure() {
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() {
+    |x: i32| { x$0 };
+}"#,
+            r#"fn foo() {
+    |x: i32| -> i32 { x };
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type_closure_wrap() {
+        mark::check!(wrap_closure_non_block_expr);
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() {
+    |x: i32| x$0;
+}"#,
+            r#"fn foo() {
+    |x: i32| -> i32 {x};
+}"#,
+        );
+    }
+
+    #[test]
+    fn infer_return_type_nested_closure() {
+        check_assist(
+            infer_function_return_type,
+            r#"fn foo() {
+    || {
+        if true {
+            3$0
+        } else {
+            5
+        }
+    }
+}"#,
+            r#"fn foo() {
+    || -> i32 {
+        if true {
+            3
+        } else {
+            5
+        }
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn not_applicable_ret_type_specified_closure() {
+        mark::check!(existing_ret_type_closure);
+        check_assist_not_applicable(
+            infer_function_return_type,
+            r#"fn foo() {
+    || -> i32 { 3$0 }
+}"#,
+        );
+    }
+
+    #[test]
+    fn not_applicable_non_tail_expr_closure() {
+        check_assist_not_applicable(
+            infer_function_return_type,
+            r#"fn foo() {
+    || -> i32 {
+        let x = 3$0;
+        6
+    }
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/inline_function.rs b/crates/ide_assists/src/handlers/inline_function.rs
new file mode 100644
index 000000000..6ec99b09b
--- /dev/null
+++ b/crates/ide_assists/src/handlers/inline_function.rs
@@ -0,0 +1,202 @@
+use ast::make;
+use hir::{HasSource, PathResolution};
+use syntax::{
+    ast::{self, edit::AstNodeEdit, ArgListOwner},
+    AstNode,
+};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind,
+};
+
+// Assist: inline_function
+//
+// Inlines a function body.
+//
+// ```
+// fn add(a: u32, b: u32) -> u32 { a + b }
+// fn main() {
+//     let x = add$0(1, 2);
+// }
+// ```
+// ->
+// ```
+// fn add(a: u32, b: u32) -> u32 { a + b }
+// fn main() {
+//     let x = {
+//         let a = 1;
+//         let b = 2;
+//         a + b
+//     };
+// }
+// ```
+pub(crate) fn inline_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let path_expr: ast::PathExpr = ctx.find_node_at_offset()?;
+    let call = path_expr.syntax().parent().and_then(ast::CallExpr::cast)?;
+    let path = path_expr.path()?;
+
+    let function = match ctx.sema.resolve_path(&path)? {
+        PathResolution::Def(hir::ModuleDef::Function(f)) => f,
+        _ => return None,
+    };
+
+    let function_source = function.source(ctx.db())?;
+    let arguments: Vec<_> = call.arg_list()?.args().collect();
+    let parameters = function_parameter_patterns(&function_source.value)?;
+
+    if arguments.len() != parameters.len() {
+        // Can't inline the function because they've passed the wrong number of
+        // arguments to this function
+        mark::hit!(inline_function_incorrect_number_of_arguments);
+        return None;
+    }
+
+    let new_bindings = parameters.into_iter().zip(arguments);
+
+    let body = function_source.value.body()?;
+
+    acc.add(
+        AssistId("inline_function", AssistKind::RefactorInline),
+        format!("Inline `{}`", path),
+        call.syntax().text_range(),
+        |builder| {
+            let mut statements: Vec<ast::Stmt> = Vec::new();
+
+            for (pattern, value) in new_bindings {
+                statements.push(make::let_stmt(pattern, Some(value)).into());
+            }
+
+            statements.extend(body.statements());
+
+            let original_indentation = call.indent_level();
+            let replacement = make::block_expr(statements, body.tail_expr())
+                .reset_indent()
+                .indent(original_indentation);
+
+            builder.replace_ast(ast::Expr::CallExpr(call), ast::Expr::BlockExpr(replacement));
+        },
+    )
+}
+
+fn function_parameter_patterns(value: &ast::Fn) -> Option<Vec<ast::Pat>> {
+    let mut patterns = Vec::new();
+
+    for param in value.param_list()?.params() {
+        let pattern = param.pat()?;
+        patterns.push(pattern);
+    }
+
+    Some(patterns)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn no_args_or_return_value_gets_inlined_without_block() {
+        check_assist(
+            inline_function,
+            r#"
+fn foo() { println!("Hello, World!"); }
+fn main() {
+    fo$0o();
+}
+"#,
+            r#"
+fn foo() { println!("Hello, World!"); }
+fn main() {
+    {
+        println!("Hello, World!");
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn args_with_side_effects() {
+        check_assist(
+            inline_function,
+            r#"
+fn foo(name: String) { println!("Hello, {}!", name); }
+fn main() {
+    foo$0(String::from("Michael"));
+}
+"#,
+            r#"
+fn foo(name: String) { println!("Hello, {}!", name); }
+fn main() {
+    {
+        let name = String::from("Michael");
+        println!("Hello, {}!", name);
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn method_inlining_isnt_supported() {
+        check_assist_not_applicable(
+            inline_function,
+            r"
+struct Foo;
+impl Foo { fn bar(&self) {} }
+
+fn main() { Foo.bar$0(); }
+",
+        );
+    }
+
+    #[test]
+    fn not_applicable_when_incorrect_number_of_parameters_are_provided() {
+        mark::check!(inline_function_incorrect_number_of_arguments);
+        check_assist_not_applicable(
+            inline_function,
+            r#"
+fn add(a: u32, b: u32) -> u32 { a + b }
+fn main() { let x = add$0(42); }
+"#,
+        );
+    }
+
+    #[test]
+    fn function_with_multiple_statements() {
+        check_assist(
+            inline_function,
+            r#"
+fn foo(a: u32, b: u32) -> u32 {
+    let x = a + b;
+    let y = x - b;
+    x * y
+}
+
+fn main() {
+    let x = foo$0(1, 2);
+}
+"#,
+            r#"
+fn foo(a: u32, b: u32) -> u32 {
+    let x = a + b;
+    let y = x - b;
+    x * y
+}
+
+fn main() {
+    let x = {
+        let a = 1;
+        let b = 2;
+        let x = a + b;
+        let y = x - b;
+        x * y
+    };
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/inline_local_variable.rs b/crates/ide_assists/src/handlers/inline_local_variable.rs
new file mode 100644
index 000000000..da5522670
--- /dev/null
+++ b/crates/ide_assists/src/handlers/inline_local_variable.rs
@@ -0,0 +1,732 @@
+use ide_db::{defs::Definition, search::FileReference};
+use rustc_hash::FxHashMap;
+use syntax::{
+    ast::{self, AstNode, AstToken},
+    TextRange,
+};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind,
+};
+
+// Assist: inline_local_variable
+//
+// Inlines local variable.
+//
+// ```
+// fn main() {
+//     let x$0 = 1 + 2;
+//     x * 4;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     (1 + 2) * 4;
+// }
+// ```
+pub(crate) fn inline_local_variable(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let let_stmt = ctx.find_node_at_offset::<ast::LetStmt>()?;
+    let bind_pat = match let_stmt.pat()? {
+        ast::Pat::IdentPat(pat) => pat,
+        _ => return None,
+    };
+    if bind_pat.mut_token().is_some() {
+        mark::hit!(test_not_inline_mut_variable);
+        return None;
+    }
+    if !bind_pat.syntax().text_range().contains_inclusive(ctx.offset()) {
+        mark::hit!(not_applicable_outside_of_bind_pat);
+        return None;
+    }
+    let initializer_expr = let_stmt.initializer()?;
+
+    let def = ctx.sema.to_def(&bind_pat)?;
+    let def = Definition::Local(def);
+    let usages = def.usages(&ctx.sema).all();
+    if usages.is_empty() {
+        mark::hit!(test_not_applicable_if_variable_unused);
+        return None;
+    };
+
+    let delete_range = if let Some(whitespace) = let_stmt
+        .syntax()
+        .next_sibling_or_token()
+        .and_then(|it| ast::Whitespace::cast(it.as_token()?.clone()))
+    {
+        TextRange::new(
+            let_stmt.syntax().text_range().start(),
+            whitespace.syntax().text_range().end(),
+        )
+    } else {
+        let_stmt.syntax().text_range()
+    };
+
+    let wrap_in_parens = usages
+        .references
+        .iter()
+        .map(|(&file_id, refs)| {
+            refs.iter()
+                .map(|&FileReference { range, .. }| {
+                    let usage_node = ctx
+                        .covering_node_for_range(range)
+                        .ancestors()
+                        .find_map(ast::PathExpr::cast)?;
+                    let usage_parent_option =
+                        usage_node.syntax().parent().and_then(ast::Expr::cast);
+                    let usage_parent = match usage_parent_option {
+                        Some(u) => u,
+                        None => return Some(false),
+                    };
+
+                    Some(!matches!(
+                        (&initializer_expr, usage_parent),
+                        (ast::Expr::CallExpr(_), _)
+                            | (ast::Expr::IndexExpr(_), _)
+                            | (ast::Expr::MethodCallExpr(_), _)
+                            | (ast::Expr::FieldExpr(_), _)
+                            | (ast::Expr::TryExpr(_), _)
+                            | (ast::Expr::RefExpr(_), _)
+                            | (ast::Expr::Literal(_), _)
+                            | (ast::Expr::TupleExpr(_), _)
+                            | (ast::Expr::ArrayExpr(_), _)
+                            | (ast::Expr::ParenExpr(_), _)
+                            | (ast::Expr::PathExpr(_), _)
+                            | (ast::Expr::BlockExpr(_), _)
+                            | (ast::Expr::EffectExpr(_), _)
+                            | (_, ast::Expr::CallExpr(_))
+                            | (_, ast::Expr::TupleExpr(_))
+                            | (_, ast::Expr::ArrayExpr(_))
+                            | (_, ast::Expr::ParenExpr(_))
+                            | (_, ast::Expr::ForExpr(_))
+                            | (_, ast::Expr::WhileExpr(_))
+                            | (_, ast::Expr::BreakExpr(_))
+                            | (_, ast::Expr::ReturnExpr(_))
+                            | (_, ast::Expr::MatchExpr(_))
+                    ))
+                })
+                .collect::<Option<_>>()
+                .map(|b| (file_id, b))
+        })
+        .collect::<Option<FxHashMap<_, Vec<_>>>>()?;
+
+    let init_str = initializer_expr.syntax().text().to_string();
+    let init_in_paren = format!("({})", &init_str);
+
+    let target = bind_pat.syntax().text_range();
+    acc.add(
+        AssistId("inline_local_variable", AssistKind::RefactorInline),
+        "Inline variable",
+        target,
+        move |builder| {
+            builder.delete(delete_range);
+            for (file_id, references) in usages.references {
+                for (&should_wrap, reference) in wrap_in_parens[&file_id].iter().zip(references) {
+                    let replacement =
+                        if should_wrap { init_in_paren.clone() } else { init_str.clone() };
+                    match reference.name.as_name_ref() {
+                        Some(name_ref)
+                            if ast::RecordExprField::for_field_name(name_ref).is_some() =>
+                        {
+                            mark::hit!(inline_field_shorthand);
+                            builder.insert(reference.range.end(), format!(": {}", replacement));
+                        }
+                        _ => builder.replace(reference.range, replacement),
+                    }
+                }
+            }
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn test_inline_let_bind_literal_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn bar(a: usize) {}
+fn foo() {
+    let a$0 = 1;
+    a + 1;
+    if a > 10 {
+    }
+
+    while a > 10 {
+
+    }
+    let b = a * 10;
+    bar(a);
+}",
+            r"
+fn bar(a: usize) {}
+fn foo() {
+    1 + 1;
+    if 1 > 10 {
+    }
+
+    while 1 > 10 {
+
+    }
+    let b = 1 * 10;
+    bar(1);
+}",
+        );
+    }
+
+    #[test]
+    fn test_inline_let_bind_bin_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn bar(a: usize) {}
+fn foo() {
+    let a$0 = 1 + 1;
+    a + 1;
+    if a > 10 {
+    }
+
+    while a > 10 {
+
+    }
+    let b = a * 10;
+    bar(a);
+}",
+            r"
+fn bar(a: usize) {}
+fn foo() {
+    (1 + 1) + 1;
+    if (1 + 1) > 10 {
+    }
+
+    while (1 + 1) > 10 {
+
+    }
+    let b = (1 + 1) * 10;
+    bar(1 + 1);
+}",
+        );
+    }
+
+    #[test]
+    fn test_inline_let_bind_function_call_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn bar(a: usize) {}
+fn foo() {
+    let a$0 = bar(1);
+    a + 1;
+    if a > 10 {
+    }
+
+    while a > 10 {
+
+    }
+    let b = a * 10;
+    bar(a);
+}",
+            r"
+fn bar(a: usize) {}
+fn foo() {
+    bar(1) + 1;
+    if bar(1) > 10 {
+    }
+
+    while bar(1) > 10 {
+
+    }
+    let b = bar(1) * 10;
+    bar(bar(1));
+}",
+        );
+    }
+
+    #[test]
+    fn test_inline_let_bind_cast_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn bar(a: usize): usize { a }
+fn foo() {
+    let a$0 = bar(1) as u64;
+    a + 1;
+    if a > 10 {
+    }
+
+    while a > 10 {
+
+    }
+    let b = a * 10;
+    bar(a);
+}",
+            r"
+fn bar(a: usize): usize { a }
+fn foo() {
+    (bar(1) as u64) + 1;
+    if (bar(1) as u64) > 10 {
+    }
+
+    while (bar(1) as u64) > 10 {
+
+    }
+    let b = (bar(1) as u64) * 10;
+    bar(bar(1) as u64);
+}",
+        );
+    }
+
+    #[test]
+    fn test_inline_let_bind_block_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = { 10 + 1 };
+    a + 1;
+    if a > 10 {
+    }
+
+    while a > 10 {
+
+    }
+    let b = a * 10;
+    bar(a);
+}",
+            r"
+fn foo() {
+    { 10 + 1 } + 1;
+    if { 10 + 1 } > 10 {
+    }
+
+    while { 10 + 1 } > 10 {
+
+    }
+    let b = { 10 + 1 } * 10;
+    bar({ 10 + 1 });
+}",
+        );
+    }
+
+    #[test]
+    fn test_inline_let_bind_paren_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = ( 10 + 1 );
+    a + 1;
+    if a > 10 {
+    }
+
+    while a > 10 {
+
+    }
+    let b = a * 10;
+    bar(a);
+}",
+            r"
+fn foo() {
+    ( 10 + 1 ) + 1;
+    if ( 10 + 1 ) > 10 {
+    }
+
+    while ( 10 + 1 ) > 10 {
+
+    }
+    let b = ( 10 + 1 ) * 10;
+    bar(( 10 + 1 ));
+}",
+        );
+    }
+
+    #[test]
+    fn test_not_inline_mut_variable() {
+        mark::check!(test_not_inline_mut_variable);
+        check_assist_not_applicable(
+            inline_local_variable,
+            r"
+fn foo() {
+    let mut a$0 = 1 + 1;
+    a + 1;
+}",
+        );
+    }
+
+    #[test]
+    fn test_call_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = bar(10 + 1);
+    let b = a * 10;
+    let c = a as usize;
+}",
+            r"
+fn foo() {
+    let b = bar(10 + 1) * 10;
+    let c = bar(10 + 1) as usize;
+}",
+        );
+    }
+
+    #[test]
+    fn test_index_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let x = vec![1, 2, 3];
+    let a$0 = x[0];
+    let b = a * 10;
+    let c = a as usize;
+}",
+            r"
+fn foo() {
+    let x = vec![1, 2, 3];
+    let b = x[0] * 10;
+    let c = x[0] as usize;
+}",
+        );
+    }
+
+    #[test]
+    fn test_method_call_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let bar = vec![1];
+    let a$0 = bar.len();
+    let b = a * 10;
+    let c = a as usize;
+}",
+            r"
+fn foo() {
+    let bar = vec![1];
+    let b = bar.len() * 10;
+    let c = bar.len() as usize;
+}",
+        );
+    }
+
+    #[test]
+    fn test_field_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+struct Bar {
+    foo: usize
+}
+
+fn foo() {
+    let bar = Bar { foo: 1 };
+    let a$0 = bar.foo;
+    let b = a * 10;
+    let c = a as usize;
+}",
+            r"
+struct Bar {
+    foo: usize
+}
+
+fn foo() {
+    let bar = Bar { foo: 1 };
+    let b = bar.foo * 10;
+    let c = bar.foo as usize;
+}",
+        );
+    }
+
+    #[test]
+    fn test_try_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() -> Option<usize> {
+    let bar = Some(1);
+    let a$0 = bar?;
+    let b = a * 10;
+    let c = a as usize;
+    None
+}",
+            r"
+fn foo() -> Option<usize> {
+    let bar = Some(1);
+    let b = bar? * 10;
+    let c = bar? as usize;
+    None
+}",
+        );
+    }
+
+    #[test]
+    fn test_ref_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let bar = 10;
+    let a$0 = &bar;
+    let b = a * 10;
+}",
+            r"
+fn foo() {
+    let bar = 10;
+    let b = &bar * 10;
+}",
+        );
+    }
+
+    #[test]
+    fn test_tuple_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = (10, 20);
+    let b = a[0];
+}",
+            r"
+fn foo() {
+    let b = (10, 20)[0];
+}",
+        );
+    }
+
+    #[test]
+    fn test_array_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = [1, 2, 3];
+    let b = a.len();
+}",
+            r"
+fn foo() {
+    let b = [1, 2, 3].len();
+}",
+        );
+    }
+
+    #[test]
+    fn test_paren() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = (10 + 20);
+    let b = a * 10;
+    let c = a as usize;
+}",
+            r"
+fn foo() {
+    let b = (10 + 20) * 10;
+    let c = (10 + 20) as usize;
+}",
+        );
+    }
+
+    #[test]
+    fn test_path_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let d = 10;
+    let a$0 = d;
+    let b = a * 10;
+    let c = a as usize;
+}",
+            r"
+fn foo() {
+    let d = 10;
+    let b = d * 10;
+    let c = d as usize;
+}",
+        );
+    }
+
+    #[test]
+    fn test_block_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = { 10 };
+    let b = a * 10;
+    let c = a as usize;
+}",
+            r"
+fn foo() {
+    let b = { 10 } * 10;
+    let c = { 10 } as usize;
+}",
+        );
+    }
+
+    #[test]
+    fn test_used_in_different_expr1() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = 10 + 20;
+    let b = a * 10;
+    let c = (a, 20);
+    let d = [a, 10];
+    let e = (a);
+}",
+            r"
+fn foo() {
+    let b = (10 + 20) * 10;
+    let c = (10 + 20, 20);
+    let d = [10 + 20, 10];
+    let e = (10 + 20);
+}",
+        );
+    }
+
+    #[test]
+    fn test_used_in_for_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = vec![10, 20];
+    for i in a {}
+}",
+            r"
+fn foo() {
+    for i in vec![10, 20] {}
+}",
+        );
+    }
+
+    #[test]
+    fn test_used_in_while_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = 1 > 0;
+    while a {}
+}",
+            r"
+fn foo() {
+    while 1 > 0 {}
+}",
+        );
+    }
+
+    #[test]
+    fn test_used_in_break_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = 1 + 1;
+    loop {
+        break a;
+    }
+}",
+            r"
+fn foo() {
+    loop {
+        break 1 + 1;
+    }
+}",
+        );
+    }
+
+    #[test]
+    fn test_used_in_return_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = 1 > 0;
+    return a;
+}",
+            r"
+fn foo() {
+    return 1 > 0;
+}",
+        );
+    }
+
+    #[test]
+    fn test_used_in_match_expr() {
+        check_assist(
+            inline_local_variable,
+            r"
+fn foo() {
+    let a$0 = 1 > 0;
+    match a {}
+}",
+            r"
+fn foo() {
+    match 1 > 0 {}
+}",
+        );
+    }
+
+    #[test]
+    fn inline_field_shorthand() {
+        mark::check!(inline_field_shorthand);
+        check_assist(
+            inline_local_variable,
+            r"
+struct S { foo: i32}
+fn main() {
+    let $0foo = 92;
+    S { foo }
+}
+",
+            r"
+struct S { foo: i32}
+fn main() {
+    S { foo: 92 }
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_not_applicable_if_variable_unused() {
+        mark::check!(test_not_applicable_if_variable_unused);
+        check_assist_not_applicable(
+            inline_local_variable,
+            r"
+fn foo() {
+    let $0a = 0;
+}
+            ",
+        )
+    }
+
+    #[test]
+    fn not_applicable_outside_of_bind_pat() {
+        mark::check!(not_applicable_outside_of_bind_pat);
+        check_assist_not_applicable(
+            inline_local_variable,
+            r"
+fn main() {
+    let x = $01 + 2;
+    x * 4;
+}
+",
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/introduce_named_lifetime.rs b/crates/ide_assists/src/handlers/introduce_named_lifetime.rs
new file mode 100644
index 000000000..02782eb6d
--- /dev/null
+++ b/crates/ide_assists/src/handlers/introduce_named_lifetime.rs
@@ -0,0 +1,315 @@
+use rustc_hash::FxHashSet;
+use syntax::{
+    ast::{self, GenericParamsOwner, NameOwner},
+    AstNode, TextRange, TextSize,
+};
+
+use crate::{assist_context::AssistBuilder, AssistContext, AssistId, AssistKind, Assists};
+
+static ASSIST_NAME: &str = "introduce_named_lifetime";
+static ASSIST_LABEL: &str = "Introduce named lifetime";
+
+// Assist: introduce_named_lifetime
+//
+// Change an anonymous lifetime to a named lifetime.
+//
+// ```
+// impl Cursor<'_$0> {
+//     fn node(self) -> &SyntaxNode {
+//         match self {
+//             Cursor::Replace(node) | Cursor::Before(node) => node,
+//         }
+//     }
+// }
+// ```
+// ->
+// ```
+// impl<'a> Cursor<'a> {
+//     fn node(self) -> &SyntaxNode {
+//         match self {
+//             Cursor::Replace(node) | Cursor::Before(node) => node,
+//         }
+//     }
+// }
+// ```
+// FIXME: How can we handle renaming any one of multiple anonymous lifetimes?
+// FIXME: should also add support for the case fun(f: &Foo) -> &$0Foo
+pub(crate) fn introduce_named_lifetime(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let lifetime =
+        ctx.find_node_at_offset::<ast::Lifetime>().filter(|lifetime| lifetime.text() == "'_")?;
+    if let Some(fn_def) = lifetime.syntax().ancestors().find_map(ast::Fn::cast) {
+        generate_fn_def_assist(acc, &fn_def, lifetime.lifetime_ident_token()?.text_range())
+    } else if let Some(impl_def) = lifetime.syntax().ancestors().find_map(ast::Impl::cast) {
+        generate_impl_def_assist(acc, &impl_def, lifetime.lifetime_ident_token()?.text_range())
+    } else {
+        None
+    }
+}
+
+/// Generate the assist for the fn def case
+fn generate_fn_def_assist(
+    acc: &mut Assists,
+    fn_def: &ast::Fn,
+    lifetime_loc: TextRange,
+) -> Option<()> {
+    let param_list: ast::ParamList = fn_def.param_list()?;
+    let new_lifetime_param = generate_unique_lifetime_param_name(&fn_def.generic_param_list())?;
+    let end_of_fn_ident = fn_def.name()?.ident_token()?.text_range().end();
+    let self_param =
+        // use the self if it's a reference and has no explicit lifetime
+        param_list.self_param().filter(|p| p.lifetime().is_none() && p.amp_token().is_some());
+    // compute the location which implicitly has the same lifetime as the anonymous lifetime
+    let loc_needing_lifetime = if let Some(self_param) = self_param {
+        // if we have a self reference, use that
+        Some(self_param.name()?.syntax().text_range().start())
+    } else {
+        // otherwise, if there's a single reference parameter without a named liftime, use that
+        let fn_params_without_lifetime: Vec<_> = param_list
+            .params()
+            .filter_map(|param| match param.ty() {
+                Some(ast::Type::RefType(ascribed_type)) if ascribed_type.lifetime().is_none() => {
+                    Some(ascribed_type.amp_token()?.text_range().end())
+                }
+                _ => None,
+            })
+            .collect();
+        match fn_params_without_lifetime.len() {
+            1 => Some(fn_params_without_lifetime.into_iter().nth(0)?),
+            0 => None,
+            // multiple unnnamed is invalid. assist is not applicable
+            _ => return None,
+        }
+    };
+    acc.add(AssistId(ASSIST_NAME, AssistKind::Refactor), ASSIST_LABEL, lifetime_loc, |builder| {
+        add_lifetime_param(fn_def, builder, end_of_fn_ident, new_lifetime_param);
+        builder.replace(lifetime_loc, format!("'{}", new_lifetime_param));
+        loc_needing_lifetime.map(|loc| builder.insert(loc, format!("'{} ", new_lifetime_param)));
+    })
+}
+
+/// Generate the assist for the impl def case
+fn generate_impl_def_assist(
+    acc: &mut Assists,
+    impl_def: &ast::Impl,
+    lifetime_loc: TextRange,
+) -> Option<()> {
+    let new_lifetime_param = generate_unique_lifetime_param_name(&impl_def.generic_param_list())?;
+    let end_of_impl_kw = impl_def.impl_token()?.text_range().end();
+    acc.add(AssistId(ASSIST_NAME, AssistKind::Refactor), ASSIST_LABEL, lifetime_loc, |builder| {
+        add_lifetime_param(impl_def, builder, end_of_impl_kw, new_lifetime_param);
+        builder.replace(lifetime_loc, format!("'{}", new_lifetime_param));
+    })
+}
+
+/// Given a type parameter list, generate a unique lifetime parameter name
+/// which is not in the list
+fn generate_unique_lifetime_param_name(
+    existing_type_param_list: &Option<ast::GenericParamList>,
+) -> Option<char> {
+    match existing_type_param_list {
+        Some(type_params) => {
+            let used_lifetime_params: FxHashSet<_> = type_params
+                .lifetime_params()
+                .map(|p| p.syntax().text().to_string()[1..].to_owned())
+                .collect();
+            (b'a'..=b'z').map(char::from).find(|c| !used_lifetime_params.contains(&c.to_string()))
+        }
+        None => Some('a'),
+    }
+}
+
+/// Add the lifetime param to `builder`. If there are type parameters in `type_params_owner`, add it to the end. Otherwise
+/// add new type params brackets with the lifetime parameter at `new_type_params_loc`.
+fn add_lifetime_param<TypeParamsOwner: ast::GenericParamsOwner>(
+    type_params_owner: &TypeParamsOwner,
+    builder: &mut AssistBuilder,
+    new_type_params_loc: TextSize,
+    new_lifetime_param: char,
+) {
+    match type_params_owner.generic_param_list() {
+        // add the new lifetime parameter to an existing type param list
+        Some(type_params) => {
+            builder.insert(
+                (u32::from(type_params.syntax().text_range().end()) - 1).into(),
+                format!(", '{}", new_lifetime_param),
+            );
+        }
+        // create a new type param list containing only the new lifetime parameter
+        None => {
+            builder.insert(new_type_params_loc, format!("<'{}>", new_lifetime_param));
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    #[test]
+    fn test_example_case() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"impl Cursor<'_$0> {
+                fn node(self) -> &SyntaxNode {
+                    match self {
+                        Cursor::Replace(node) | Cursor::Before(node) => node,
+                    }
+                }
+            }"#,
+            r#"impl<'a> Cursor<'a> {
+                fn node(self) -> &SyntaxNode {
+                    match self {
+                        Cursor::Replace(node) | Cursor::Before(node) => node,
+                    }
+                }
+            }"#,
+        );
+    }
+
+    #[test]
+    fn test_example_case_simplified() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"impl Cursor<'_$0> {"#,
+            r#"impl<'a> Cursor<'a> {"#,
+        );
+    }
+
+    #[test]
+    fn test_example_case_cursor_after_tick() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"impl Cursor<'$0_> {"#,
+            r#"impl<'a> Cursor<'a> {"#,
+        );
+    }
+
+    #[test]
+    fn test_impl_with_other_type_param() {
+        check_assist(
+            introduce_named_lifetime,
+            "impl<I> fmt::Display for SepByBuilder<'_$0, I>
+        where
+            I: Iterator,
+            I::Item: fmt::Display,
+        {",
+            "impl<I, 'a> fmt::Display for SepByBuilder<'a, I>
+        where
+            I: Iterator,
+            I::Item: fmt::Display,
+        {",
+        )
+    }
+
+    #[test]
+    fn test_example_case_cursor_before_tick() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"impl Cursor<$0'_> {"#,
+            r#"impl<'a> Cursor<'a> {"#,
+        );
+    }
+
+    #[test]
+    fn test_not_applicable_cursor_position() {
+        check_assist_not_applicable(introduce_named_lifetime, r#"impl Cursor<'_>$0 {"#);
+        check_assist_not_applicable(introduce_named_lifetime, r#"impl Cursor$0<'_> {"#);
+    }
+
+    #[test]
+    fn test_not_applicable_lifetime_already_name() {
+        check_assist_not_applicable(introduce_named_lifetime, r#"impl Cursor<'a$0> {"#);
+        check_assist_not_applicable(introduce_named_lifetime, r#"fn my_fun<'a>() -> X<'a$0>"#);
+    }
+
+    #[test]
+    fn test_with_type_parameter() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"impl<T> Cursor<T, '_$0>"#,
+            r#"impl<T, 'a> Cursor<T, 'a>"#,
+        );
+    }
+
+    #[test]
+    fn test_with_existing_lifetime_name_conflict() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"impl<'a, 'b> Cursor<'a, 'b, '_$0>"#,
+            r#"impl<'a, 'b, 'c> Cursor<'a, 'b, 'c>"#,
+        );
+    }
+
+    #[test]
+    fn test_function_return_value_anon_lifetime_param() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"fn my_fun() -> X<'_$0>"#,
+            r#"fn my_fun<'a>() -> X<'a>"#,
+        );
+    }
+
+    #[test]
+    fn test_function_return_value_anon_reference_lifetime() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"fn my_fun() -> &'_$0 X"#,
+            r#"fn my_fun<'a>() -> &'a X"#,
+        );
+    }
+
+    #[test]
+    fn test_function_param_anon_lifetime() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"fn my_fun(x: X<'_$0>)"#,
+            r#"fn my_fun<'a>(x: X<'a>)"#,
+        );
+    }
+
+    #[test]
+    fn test_function_add_lifetime_to_params() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"fn my_fun(f: &Foo) -> X<'_$0>"#,
+            r#"fn my_fun<'a>(f: &'a Foo) -> X<'a>"#,
+        );
+    }
+
+    #[test]
+    fn test_function_add_lifetime_to_params_in_presence_of_other_lifetime() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"fn my_fun<'other>(f: &Foo, b: &'other Bar) -> X<'_$0>"#,
+            r#"fn my_fun<'other, 'a>(f: &'a Foo, b: &'other Bar) -> X<'a>"#,
+        );
+    }
+
+    #[test]
+    fn test_function_not_applicable_without_self_and_multiple_unnamed_param_lifetimes() {
+        // this is not permitted under lifetime elision rules
+        check_assist_not_applicable(
+            introduce_named_lifetime,
+            r#"fn my_fun(f: &Foo, b: &Bar) -> X<'_$0>"#,
+        );
+    }
+
+    #[test]
+    fn test_function_add_lifetime_to_self_ref_param() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"fn my_fun<'other>(&self, f: &Foo, b: &'other Bar) -> X<'_$0>"#,
+            r#"fn my_fun<'other, 'a>(&'a self, f: &Foo, b: &'other Bar) -> X<'a>"#,
+        );
+    }
+
+    #[test]
+    fn test_function_add_lifetime_to_param_with_non_ref_self() {
+        check_assist(
+            introduce_named_lifetime,
+            r#"fn my_fun<'other>(self, f: &Foo, b: &'other Bar) -> X<'_$0>"#,
+            r#"fn my_fun<'other, 'a>(self, f: &'a Foo, b: &'other Bar) -> X<'a>"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/invert_if.rs b/crates/ide_assists/src/handlers/invert_if.rs
new file mode 100644
index 000000000..5b69dafd4
--- /dev/null
+++ b/crates/ide_assists/src/handlers/invert_if.rs
@@ -0,0 +1,146 @@
+use syntax::{
+    ast::{self, AstNode},
+    T,
+};
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    utils::invert_boolean_expression,
+    AssistId, AssistKind,
+};
+
+// Assist: invert_if
+//
+// Apply invert_if
+// This transforms if expressions of the form `if !x {A} else {B}` into `if x {B} else {A}`
+// This also works with `!=`. This assist can only be applied with the cursor
+// on `if`.
+//
+// ```
+// fn main() {
+//     if$0 !y { A } else { B }
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     if y { B } else { A }
+// }
+// ```
+
+pub(crate) fn invert_if(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let if_keyword = ctx.find_token_syntax_at_offset(T![if])?;
+    let expr = ast::IfExpr::cast(if_keyword.parent())?;
+    let if_range = if_keyword.text_range();
+    let cursor_in_range = if_range.contains_range(ctx.frange.range);
+    if !cursor_in_range {
+        return None;
+    }
+
+    // This assist should not apply for if-let.
+    if expr.condition()?.pat().is_some() {
+        return None;
+    }
+
+    let cond = expr.condition()?.expr()?;
+    let then_node = expr.then_branch()?.syntax().clone();
+    let else_block = match expr.else_branch()? {
+        ast::ElseBranch::Block(it) => it,
+        ast::ElseBranch::IfExpr(_) => return None,
+    };
+
+    acc.add(AssistId("invert_if", AssistKind::RefactorRewrite), "Invert if", if_range, |edit| {
+        let flip_cond = invert_boolean_expression(cond.clone());
+        edit.replace_ast(cond, flip_cond);
+
+        let else_node = else_block.syntax();
+        let else_range = else_node.text_range();
+        let then_range = then_node.text_range();
+
+        edit.replace(else_range, then_node.text());
+        edit.replace(then_range, else_node.text());
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    #[test]
+    fn invert_if_composite_condition() {
+        check_assist(
+            invert_if,
+            "fn f() { i$0f x == 3 || x == 4 || x == 5 { 1 } else { 3 * 2 } }",
+            "fn f() { if !(x == 3 || x == 4 || x == 5) { 3 * 2 } else { 1 } }",
+        )
+    }
+
+    #[test]
+    fn invert_if_remove_not_parentheses() {
+        check_assist(
+            invert_if,
+            "fn f() { i$0f !(x == 3 || x == 4 || x == 5) { 3 * 2 } else { 1 } }",
+            "fn f() { if x == 3 || x == 4 || x == 5 { 1 } else { 3 * 2 } }",
+        )
+    }
+
+    #[test]
+    fn invert_if_remove_inequality() {
+        check_assist(
+            invert_if,
+            "fn f() { i$0f x != 3 { 1 } else { 3 + 2 } }",
+            "fn f() { if x == 3 { 3 + 2 } else { 1 } }",
+        )
+    }
+
+    #[test]
+    fn invert_if_remove_not() {
+        check_assist(
+            invert_if,
+            "fn f() { $0if !cond { 3 * 2 } else { 1 } }",
+            "fn f() { if cond { 1 } else { 3 * 2 } }",
+        )
+    }
+
+    #[test]
+    fn invert_if_general_case() {
+        check_assist(
+            invert_if,
+            "fn f() { i$0f cond { 3 * 2 } else { 1 } }",
+            "fn f() { if !cond { 1 } else { 3 * 2 } }",
+        )
+    }
+
+    #[test]
+    fn invert_if_doesnt_apply_with_cursor_not_on_if() {
+        check_assist_not_applicable(invert_if, "fn f() { if !$0cond { 3 * 2 } else { 1 } }")
+    }
+
+    #[test]
+    fn invert_if_doesnt_apply_with_if_let() {
+        check_assist_not_applicable(
+            invert_if,
+            "fn f() { i$0f let Some(_) = Some(1) { 1 } else { 0 } }",
+        )
+    }
+
+    #[test]
+    fn invert_if_option_case() {
+        check_assist(
+            invert_if,
+            "fn f() { if$0 doc_style.is_some() { Class::DocComment } else { Class::Comment } }",
+            "fn f() { if doc_style.is_none() { Class::Comment } else { Class::DocComment } }",
+        )
+    }
+
+    #[test]
+    fn invert_if_result_case() {
+        check_assist(
+            invert_if,
+            "fn f() { i$0f doc_style.is_err() { Class::Err } else { Class::Ok } }",
+            "fn f() { if doc_style.is_ok() { Class::Ok } else { Class::Err } }",
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/merge_imports.rs b/crates/ide_assists/src/handlers/merge_imports.rs
new file mode 100644
index 000000000..7bd7e1e36
--- /dev/null
+++ b/crates/ide_assists/src/handlers/merge_imports.rs
@@ -0,0 +1,343 @@
+use ide_db::helpers::insert_use::{try_merge_imports, try_merge_trees, MergeBehavior};
+use syntax::{
+    algo::{neighbor, SyntaxRewriter},
+    ast, AstNode,
+};
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    utils::next_prev,
+    AssistId, AssistKind,
+};
+
+// Assist: merge_imports
+//
+// Merges two imports with a common prefix.
+//
+// ```
+// use std::$0fmt::Formatter;
+// use std::io;
+// ```
+// ->
+// ```
+// use std::{fmt::Formatter, io};
+// ```
+pub(crate) fn merge_imports(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let tree: ast::UseTree = ctx.find_node_at_offset()?;
+    let mut rewriter = SyntaxRewriter::default();
+    let mut offset = ctx.offset();
+
+    if let Some(use_item) = tree.syntax().parent().and_then(ast::Use::cast) {
+        let (merged, to_delete) =
+            next_prev().filter_map(|dir| neighbor(&use_item, dir)).find_map(|use_item2| {
+                try_merge_imports(&use_item, &use_item2, MergeBehavior::Full).zip(Some(use_item2))
+            })?;
+
+        rewriter.replace_ast(&use_item, &merged);
+        rewriter += to_delete.remove();
+
+        if to_delete.syntax().text_range().end() < offset {
+            offset -= to_delete.syntax().text_range().len();
+        }
+    } else {
+        let (merged, to_delete) =
+            next_prev().filter_map(|dir| neighbor(&tree, dir)).find_map(|use_tree| {
+                try_merge_trees(&tree, &use_tree, MergeBehavior::Full).zip(Some(use_tree))
+            })?;
+
+        rewriter.replace_ast(&tree, &merged);
+        rewriter += to_delete.remove();
+
+        if to_delete.syntax().text_range().end() < offset {
+            offset -= to_delete.syntax().text_range().len();
+        }
+    };
+
+    let target = tree.syntax().text_range();
+    acc.add(
+        AssistId("merge_imports", AssistKind::RefactorRewrite),
+        "Merge imports",
+        target,
+        |builder| {
+            builder.rewrite(rewriter);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn test_merge_equal() {
+        check_assist(
+            merge_imports,
+            r"
+use std::fmt$0::{Display, Debug};
+use std::fmt::{Display, Debug};
+",
+            r"
+use std::fmt::{Debug, Display};
+",
+        )
+    }
+
+    #[test]
+    fn test_merge_first() {
+        check_assist(
+            merge_imports,
+            r"
+use std::fmt$0::Debug;
+use std::fmt::Display;
+",
+            r"
+use std::fmt::{Debug, Display};
+",
+        )
+    }
+
+    #[test]
+    fn test_merge_second() {
+        check_assist(
+            merge_imports,
+            r"
+use std::fmt::Debug;
+use std::fmt$0::Display;
+",
+            r"
+use std::fmt::{Debug, Display};
+",
+        );
+    }
+
+    #[test]
+    fn merge_self1() {
+        check_assist(
+            merge_imports,
+            r"
+use std::fmt$0;
+use std::fmt::Display;
+",
+            r"
+use std::fmt::{self, Display};
+",
+        );
+    }
+
+    #[test]
+    fn merge_self2() {
+        check_assist(
+            merge_imports,
+            r"
+use std::{fmt, $0fmt::Display};
+",
+            r"
+use std::{fmt::{self, Display}};
+",
+        );
+    }
+
+    #[test]
+    fn skip_pub1() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+pub use std::fmt$0::Debug;
+use std::fmt::Display;
+",
+        );
+    }
+
+    #[test]
+    fn skip_pub_last() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+use std::fmt$0::Debug;
+pub use std::fmt::Display;
+",
+        );
+    }
+
+    #[test]
+    fn skip_pub_crate_pub() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+pub(crate) use std::fmt$0::Debug;
+pub use std::fmt::Display;
+",
+        );
+    }
+
+    #[test]
+    fn skip_pub_pub_crate() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+pub use std::fmt$0::Debug;
+pub(crate) use std::fmt::Display;
+",
+        );
+    }
+
+    #[test]
+    fn merge_pub() {
+        check_assist(
+            merge_imports,
+            r"
+pub use std::fmt$0::Debug;
+pub use std::fmt::Display;
+",
+            r"
+pub use std::fmt::{Debug, Display};
+",
+        )
+    }
+
+    #[test]
+    fn merge_pub_crate() {
+        check_assist(
+            merge_imports,
+            r"
+pub(crate) use std::fmt$0::Debug;
+pub(crate) use std::fmt::Display;
+",
+            r"
+pub(crate) use std::fmt::{Debug, Display};
+",
+        )
+    }
+
+    #[test]
+    fn test_merge_nested() {
+        check_assist(
+            merge_imports,
+            r"
+use std::{fmt$0::Debug, fmt::Display};
+",
+            r"
+use std::{fmt::{Debug, Display}};
+",
+        );
+    }
+
+    #[test]
+    fn test_merge_nested2() {
+        check_assist(
+            merge_imports,
+            r"
+use std::{fmt::Debug, fmt$0::Display};
+",
+            r"
+use std::{fmt::{Debug, Display}};
+",
+        );
+    }
+
+    #[test]
+    fn test_merge_single_wildcard_diff_prefixes() {
+        check_assist(
+            merge_imports,
+            r"
+use std$0::cell::*;
+use std::str;
+",
+            r"
+use std::{cell::*, str};
+",
+        )
+    }
+
+    #[test]
+    fn test_merge_both_wildcard_diff_prefixes() {
+        check_assist(
+            merge_imports,
+            r"
+use std$0::cell::*;
+use std::str::*;
+",
+            r"
+use std::{cell::*, str::*};
+",
+        )
+    }
+
+    #[test]
+    fn removes_just_enough_whitespace() {
+        check_assist(
+            merge_imports,
+            r"
+use foo$0::bar;
+use foo::baz;
+
+/// Doc comment
+",
+            r"
+use foo::{bar, baz};
+
+/// Doc comment
+",
+        );
+    }
+
+    #[test]
+    fn works_with_trailing_comma() {
+        check_assist(
+            merge_imports,
+            r"
+use {
+    foo$0::bar,
+    foo::baz,
+};
+",
+            r"
+use {
+    foo::{bar, baz},
+};
+",
+        );
+        check_assist(
+            merge_imports,
+            r"
+use {
+    foo::baz,
+    foo$0::bar,
+};
+",
+            r"
+use {
+    foo::{bar, baz},
+};
+",
+        );
+    }
+
+    #[test]
+    fn test_double_comma() {
+        check_assist(
+            merge_imports,
+            r"
+use foo::bar::baz;
+use foo::$0{
+    FooBar,
+};
+",
+            r"
+use foo::{FooBar, bar::baz};
+",
+        )
+    }
+
+    #[test]
+    fn test_empty_use() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+use std::$0
+fn main() {}",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/merge_match_arms.rs b/crates/ide_assists/src/handlers/merge_match_arms.rs
new file mode 100644
index 000000000..9bf076cb9
--- /dev/null
+++ b/crates/ide_assists/src/handlers/merge_match_arms.rs
@@ -0,0 +1,248 @@
+use std::iter::successors;
+
+use syntax::{
+    algo::neighbor,
+    ast::{self, AstNode},
+    Direction,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists, TextRange};
+
+// Assist: merge_match_arms
+//
+// Merges identical match arms.
+//
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         $0Action::Move(..) => foo(),
+//         Action::Stop => foo(),
+//     }
+// }
+// ```
+// ->
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move(..) | Action::Stop => foo(),
+//     }
+// }
+// ```
+pub(crate) fn merge_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let current_arm = ctx.find_node_at_offset::<ast::MatchArm>()?;
+    // Don't try to handle arms with guards for now - can add support for this later
+    if current_arm.guard().is_some() {
+        return None;
+    }
+    let current_expr = current_arm.expr()?;
+    let current_text_range = current_arm.syntax().text_range();
+
+    // We check if the following match arms match this one. We could, but don't,
+    // compare to the previous match arm as well.
+    let arms_to_merge = successors(Some(current_arm), |it| neighbor(it, Direction::Next))
+        .take_while(|arm| {
+            if arm.guard().is_some() {
+                return false;
+            }
+            match arm.expr() {
+                Some(expr) => expr.syntax().text() == current_expr.syntax().text(),
+                None => false,
+            }
+        })
+        .collect::<Vec<_>>();
+
+    if arms_to_merge.len() <= 1 {
+        return None;
+    }
+
+    acc.add(
+        AssistId("merge_match_arms", AssistKind::RefactorRewrite),
+        "Merge match arms",
+        current_text_range,
+        |edit| {
+            let pats = if arms_to_merge.iter().any(contains_placeholder) {
+                "_".into()
+            } else {
+                arms_to_merge
+                    .iter()
+                    .filter_map(ast::MatchArm::pat)
+                    .map(|x| x.syntax().to_string())
+                    .collect::<Vec<String>>()
+                    .join(" | ")
+            };
+
+            let arm = format!("{} => {}", pats, current_expr.syntax().text());
+
+            let start = arms_to_merge.first().unwrap().syntax().text_range().start();
+            let end = arms_to_merge.last().unwrap().syntax().text_range().end();
+
+            edit.replace(TextRange::new(start, end), arm);
+        },
+    )
+}
+
+fn contains_placeholder(a: &ast::MatchArm) -> bool {
+    matches!(a.pat(), Some(ast::Pat::WildcardPat(..)))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn merge_match_arms_single_patterns() {
+        check_assist(
+            merge_match_arms,
+            r#"
+            #[derive(Debug)]
+            enum X { A, B, C }
+
+            fn main() {
+                let x = X::A;
+                let y = match x {
+                    X::A => { 1i32$0 }
+                    X::B => { 1i32 }
+                    X::C => { 2i32 }
+                }
+            }
+            "#,
+            r#"
+            #[derive(Debug)]
+            enum X { A, B, C }
+
+            fn main() {
+                let x = X::A;
+                let y = match x {
+                    X::A | X::B => { 1i32 }
+                    X::C => { 2i32 }
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn merge_match_arms_multiple_patterns() {
+        check_assist(
+            merge_match_arms,
+            r#"
+            #[derive(Debug)]
+            enum X { A, B, C, D, E }
+
+            fn main() {
+                let x = X::A;
+                let y = match x {
+                    X::A | X::B => {$0 1i32 },
+                    X::C | X::D => { 1i32 },
+                    X::E => { 2i32 },
+                }
+            }
+            "#,
+            r#"
+            #[derive(Debug)]
+            enum X { A, B, C, D, E }
+
+            fn main() {
+                let x = X::A;
+                let y = match x {
+                    X::A | X::B | X::C | X::D => { 1i32 },
+                    X::E => { 2i32 },
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn merge_match_arms_placeholder_pattern() {
+        check_assist(
+            merge_match_arms,
+            r#"
+            #[derive(Debug)]
+            enum X { A, B, C, D, E }
+
+            fn main() {
+                let x = X::A;
+                let y = match x {
+                    X::A => { 1i32 },
+                    X::B => { 2i$032 },
+                    _ => { 2i32 }
+                }
+            }
+            "#,
+            r#"
+            #[derive(Debug)]
+            enum X { A, B, C, D, E }
+
+            fn main() {
+                let x = X::A;
+                let y = match x {
+                    X::A => { 1i32 },
+                    _ => { 2i32 }
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn merges_all_subsequent_arms() {
+        check_assist(
+            merge_match_arms,
+            r#"
+            enum X { A, B, C, D, E }
+
+            fn main() {
+                match X::A {
+                    X::A$0 => 92,
+                    X::B => 92,
+                    X::C => 92,
+                    X::D => 62,
+                    _ => panic!(),
+                }
+            }
+            "#,
+            r#"
+            enum X { A, B, C, D, E }
+
+            fn main() {
+                match X::A {
+                    X::A | X::B | X::C => 92,
+                    X::D => 62,
+                    _ => panic!(),
+                }
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn merge_match_arms_rejects_guards() {
+        check_assist_not_applicable(
+            merge_match_arms,
+            r#"
+            #[derive(Debug)]
+            enum X {
+                A(i32),
+                B,
+                C
+            }
+
+            fn main() {
+                let x = X::A;
+                let y = match x {
+                    X::A(a) if a > 5 => { $01i32 },
+                    X::B => { 1i32 },
+                    X::C => { 2i32 }
+                }
+            }
+            "#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/move_bounds.rs b/crates/ide_assists/src/handlers/move_bounds.rs
new file mode 100644
index 000000000..cf260c6f8
--- /dev/null
+++ b/crates/ide_assists/src/handlers/move_bounds.rs
@@ -0,0 +1,152 @@
+use syntax::{
+    ast::{self, edit::AstNodeEdit, make, AstNode, NameOwner, TypeBoundsOwner},
+    match_ast,
+    SyntaxKind::*,
+    T,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: move_bounds_to_where_clause
+//
+// Moves inline type bounds to a where clause.
+//
+// ```
+// fn apply<T, U, $0F: FnOnce(T) -> U>(f: F, x: T) -> U {
+//     f(x)
+// }
+// ```
+// ->
+// ```
+// fn apply<T, U, F>(f: F, x: T) -> U where F: FnOnce(T) -> U {
+//     f(x)
+// }
+// ```
+pub(crate) fn move_bounds_to_where_clause(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let type_param_list = ctx.find_node_at_offset::<ast::GenericParamList>()?;
+
+    let mut type_params = type_param_list.type_params();
+    if type_params.all(|p| p.type_bound_list().is_none()) {
+        return None;
+    }
+
+    let parent = type_param_list.syntax().parent()?;
+    if parent.children_with_tokens().any(|it| it.kind() == WHERE_CLAUSE) {
+        return None;
+    }
+
+    let anchor = match_ast! {
+        match parent {
+            ast::Fn(it) => it.body()?.syntax().clone().into(),
+            ast::Trait(it) => it.assoc_item_list()?.syntax().clone().into(),
+            ast::Impl(it) => it.assoc_item_list()?.syntax().clone().into(),
+            ast::Enum(it) => it.variant_list()?.syntax().clone().into(),
+            ast::Struct(it) => {
+                it.syntax().children_with_tokens()
+                    .find(|it| it.kind() == RECORD_FIELD_LIST || it.kind() == T![;])?
+            },
+            _ => return None
+        }
+    };
+
+    let target = type_param_list.syntax().text_range();
+    acc.add(
+        AssistId("move_bounds_to_where_clause", AssistKind::RefactorRewrite),
+        "Move to where clause",
+        target,
+        |edit| {
+            let new_params = type_param_list
+                .type_params()
+                .filter(|it| it.type_bound_list().is_some())
+                .map(|type_param| {
+                    let without_bounds = type_param.remove_bounds();
+                    (type_param, without_bounds)
+                });
+
+            let new_type_param_list = type_param_list.replace_descendants(new_params);
+            edit.replace_ast(type_param_list.clone(), new_type_param_list);
+
+            let where_clause = {
+                let predicates = type_param_list.type_params().filter_map(build_predicate);
+                make::where_clause(predicates)
+            };
+
+            let to_insert = match anchor.prev_sibling_or_token() {
+                Some(ref elem) if elem.kind() == WHITESPACE => {
+                    format!("{} ", where_clause.syntax())
+                }
+                _ => format!(" {}", where_clause.syntax()),
+            };
+            edit.insert(anchor.text_range().start(), to_insert);
+        },
+    )
+}
+
+fn build_predicate(param: ast::TypeParam) -> Option<ast::WherePred> {
+    let path = {
+        let name_ref = make::name_ref(&param.name()?.syntax().to_string());
+        let segment = make::path_segment(name_ref);
+        make::path_unqualified(segment)
+    };
+    let predicate = make::where_pred(path, param.type_bound_list()?.bounds());
+    Some(predicate)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::check_assist;
+
+    #[test]
+    fn move_bounds_to_where_clause_fn() {
+        check_assist(
+            move_bounds_to_where_clause,
+            r#"
+            fn foo<T: u32, $0F: FnOnce(T) -> T>() {}
+            "#,
+            r#"
+            fn foo<T, F>() where T: u32, F: FnOnce(T) -> T {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn move_bounds_to_where_clause_impl() {
+        check_assist(
+            move_bounds_to_where_clause,
+            r#"
+            impl<U: u32, $0T> A<U, T> {}
+            "#,
+            r#"
+            impl<U, T> A<U, T> where U: u32 {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn move_bounds_to_where_clause_struct() {
+        check_assist(
+            move_bounds_to_where_clause,
+            r#"
+            struct A<$0T: Iterator<Item = u32>> {}
+            "#,
+            r#"
+            struct A<T> where T: Iterator<Item = u32> {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn move_bounds_to_where_clause_tuple_struct() {
+        check_assist(
+            move_bounds_to_where_clause,
+            r#"
+            struct Pair<$0T: u32>(T, T);
+            "#,
+            r#"
+            struct Pair<T>(T, T) where T: u32;
+            "#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/move_guard.rs b/crates/ide_assists/src/handlers/move_guard.rs
new file mode 100644
index 000000000..3f22302a9
--- /dev/null
+++ b/crates/ide_assists/src/handlers/move_guard.rs
@@ -0,0 +1,367 @@
+use syntax::{
+    ast::{edit::AstNodeEdit, make, AstNode, BlockExpr, Expr, IfExpr, MatchArm},
+    SyntaxKind::WHITESPACE,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: move_guard_to_arm_body
+//
+// Moves match guard into match arm body.
+//
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move { distance } $0if distance > 10 => foo(),
+//         _ => (),
+//     }
+// }
+// ```
+// ->
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move { distance } => if distance > 10 {
+//             foo()
+//         },
+//         _ => (),
+//     }
+// }
+// ```
+pub(crate) fn move_guard_to_arm_body(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let match_arm = ctx.find_node_at_offset::<MatchArm>()?;
+    let guard = match_arm.guard()?;
+    let space_before_guard = guard.syntax().prev_sibling_or_token();
+
+    let guard_condition = guard.expr()?;
+    let arm_expr = match_arm.expr()?;
+    let if_expr = make::expr_if(
+        make::condition(guard_condition, None),
+        make::block_expr(None, Some(arm_expr.clone())),
+        None,
+    )
+    .indent(arm_expr.indent_level());
+
+    let target = guard.syntax().text_range();
+    acc.add(
+        AssistId("move_guard_to_arm_body", AssistKind::RefactorRewrite),
+        "Move guard to arm body",
+        target,
+        |edit| {
+            match space_before_guard {
+                Some(element) if element.kind() == WHITESPACE => {
+                    edit.delete(element.text_range());
+                }
+                _ => (),
+            };
+
+            edit.delete(guard.syntax().text_range());
+            edit.replace_ast(arm_expr, if_expr);
+        },
+    )
+}
+
+// Assist: move_arm_cond_to_match_guard
+//
+// Moves if expression from match arm body into a guard.
+//
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move { distance } => $0if distance > 10 { foo() },
+//         _ => (),
+//     }
+// }
+// ```
+// ->
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move { distance } if distance > 10 => foo(),
+//         _ => (),
+//     }
+// }
+// ```
+pub(crate) fn move_arm_cond_to_match_guard(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let match_arm: MatchArm = ctx.find_node_at_offset::<MatchArm>()?;
+    let match_pat = match_arm.pat()?;
+    let arm_body = match_arm.expr()?;
+
+    let mut replace_node = None;
+    let if_expr: IfExpr = IfExpr::cast(arm_body.syntax().clone()).or_else(|| {
+        let block_expr = BlockExpr::cast(arm_body.syntax().clone())?;
+        if let Expr::IfExpr(e) = block_expr.tail_expr()? {
+            replace_node = Some(block_expr.syntax().clone());
+            Some(e)
+        } else {
+            None
+        }
+    })?;
+    let replace_node = replace_node.unwrap_or_else(|| if_expr.syntax().clone());
+
+    let cond = if_expr.condition()?;
+    let then_block = if_expr.then_branch()?;
+
+    // Not support if with else branch
+    if if_expr.else_branch().is_some() {
+        return None;
+    }
+    // Not support moving if let to arm guard
+    if cond.pat().is_some() {
+        return None;
+    }
+
+    let buf = format!(" if {}", cond.syntax().text());
+
+    acc.add(
+        AssistId("move_arm_cond_to_match_guard", AssistKind::RefactorRewrite),
+        "Move condition to match guard",
+        replace_node.text_range(),
+        |edit| {
+            let then_only_expr = then_block.statements().next().is_none();
+
+            match &then_block.tail_expr() {
+                Some(then_expr) if then_only_expr => {
+                    edit.replace(replace_node.text_range(), then_expr.syntax().text())
+                }
+                _ if replace_node != *if_expr.syntax() => {
+                    // Dedent because if_expr is in a BlockExpr
+                    let replace_with = then_block.dedent(1.into()).syntax().text();
+                    edit.replace(replace_node.text_range(), replace_with)
+                }
+                _ => edit.replace(replace_node.text_range(), then_block.syntax().text()),
+            }
+
+            edit.insert(match_pat.syntax().text_range().end(), buf);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    #[test]
+    fn move_guard_to_arm_body_target() {
+        check_assist_target(
+            move_guard_to_arm_body,
+            r#"
+fn main() {
+    match 92 {
+        x $0if x > 10 => false,
+        _ => true
+    }
+}
+"#,
+            r#"if x > 10"#,
+        );
+    }
+
+    #[test]
+    fn move_guard_to_arm_body_works() {
+        check_assist(
+            move_guard_to_arm_body,
+            r#"
+fn main() {
+    match 92 {
+        x $0if x > 10 => false,
+        _ => true
+    }
+}
+"#,
+            r#"
+fn main() {
+    match 92 {
+        x => if x > 10 {
+            false
+        },
+        _ => true
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn move_guard_to_arm_body_works_complex_match() {
+        check_assist(
+            move_guard_to_arm_body,
+            r#"
+fn main() {
+    match 92 {
+        $0x @ 4 | x @ 5    if x > 5 => true,
+        _ => false
+    }
+}
+"#,
+            r#"
+fn main() {
+    match 92 {
+        x @ 4 | x @ 5 => if x > 5 {
+            true
+        },
+        _ => false
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn move_arm_cond_to_match_guard_works() {
+        check_assist(
+            move_arm_cond_to_match_guard,
+            r#"
+fn main() {
+    match 92 {
+        x => if x > 10 { $0false },
+        _ => true
+    }
+}
+"#,
+            r#"
+fn main() {
+    match 92 {
+        x if x > 10 => false,
+        _ => true
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn move_arm_cond_in_block_to_match_guard_works() {
+        check_assist(
+            move_arm_cond_to_match_guard,
+            r#"
+fn main() {
+    match 92 {
+        x => {
+            $0if x > 10 {
+                false
+            }
+        },
+        _ => true
+    }
+}
+"#,
+            r#"
+fn main() {
+    match 92 {
+        x if x > 10 => false,
+        _ => true
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn move_arm_cond_to_match_guard_if_let_not_works() {
+        check_assist_not_applicable(
+            move_arm_cond_to_match_guard,
+            r#"
+fn main() {
+    match 92 {
+        x => if let 62 = x { $0false },
+        _ => true
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn move_arm_cond_to_match_guard_if_empty_body_works() {
+        check_assist(
+            move_arm_cond_to_match_guard,
+            r#"
+fn main() {
+    match 92 {
+        x => if x > 10 { $0 },
+        _ => true
+    }
+}
+"#,
+            r#"
+fn main() {
+    match 92 {
+        x if x > 10 => {  },
+        _ => true
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn move_arm_cond_to_match_guard_if_multiline_body_works() {
+        check_assist(
+            move_arm_cond_to_match_guard,
+            r#"
+fn main() {
+    match 92 {
+        x => if x > 10 {
+            92;$0
+            false
+        },
+        _ => true
+    }
+}
+"#,
+            r#"
+fn main() {
+    match 92 {
+        x if x > 10 => {
+            92;
+            false
+        },
+        _ => true
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn move_arm_cond_in_block_to_match_guard_if_multiline_body_works() {
+        check_assist(
+            move_arm_cond_to_match_guard,
+            r#"
+fn main() {
+    match 92 {
+        x => {
+            if x > 10 {
+                92;$0
+                false
+            }
+        }
+        _ => true
+    }
+}
+"#,
+            r#"
+fn main() {
+    match 92 {
+        x if x > 10 => {
+            92;
+            false
+        }
+        _ => true
+    }
+}
+"#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/move_module_to_file.rs b/crates/ide_assists/src/handlers/move_module_to_file.rs
new file mode 100644
index 000000000..91c395c1b
--- /dev/null
+++ b/crates/ide_assists/src/handlers/move_module_to_file.rs
@@ -0,0 +1,188 @@
+use ast::{edit::IndentLevel, VisibilityOwner};
+use ide_db::base_db::AnchoredPathBuf;
+use stdx::format_to;
+use syntax::{
+    ast::{self, edit::AstNodeEdit, NameOwner},
+    AstNode, TextRange,
+};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: move_module_to_file
+//
+// Moves inline module's contents to a separate file.
+//
+// ```
+// mod $0foo {
+//     fn t() {}
+// }
+// ```
+// ->
+// ```
+// mod foo;
+// ```
+pub(crate) fn move_module_to_file(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let module_ast = ctx.find_node_at_offset::<ast::Module>()?;
+    let module_items = module_ast.item_list()?;
+
+    let l_curly_offset = module_items.syntax().text_range().start();
+    if l_curly_offset <= ctx.offset() {
+        mark::hit!(available_before_curly);
+        return None;
+    }
+    let target = TextRange::new(module_ast.syntax().text_range().start(), l_curly_offset);
+
+    let module_name = module_ast.name()?;
+
+    let module_def = ctx.sema.to_def(&module_ast)?;
+    let parent_module = module_def.parent(ctx.db())?;
+
+    acc.add(
+        AssistId("move_module_to_file", AssistKind::RefactorExtract),
+        "Extract module to file",
+        target,
+        |builder| {
+            let path = {
+                let dir = match parent_module.name(ctx.db()) {
+                    Some(name) if !parent_module.is_mod_rs(ctx.db()) => format!("{}/", name),
+                    _ => String::new(),
+                };
+                format!("./{}{}.rs", dir, module_name)
+            };
+            let contents = {
+                let items = module_items.dedent(IndentLevel(1)).to_string();
+                let mut items =
+                    items.trim_start_matches('{').trim_end_matches('}').trim().to_string();
+                if !items.is_empty() {
+                    items.push('\n');
+                }
+                items
+            };
+
+            let mut buf = String::new();
+            if let Some(v) = module_ast.visibility() {
+                format_to!(buf, "{} ", v);
+            }
+            format_to!(buf, "mod {};", module_name);
+
+            builder.replace(module_ast.syntax().text_range(), buf);
+
+            let dst = AnchoredPathBuf { anchor: ctx.frange.file_id, path };
+            builder.create_file(dst, contents);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn extract_from_root() {
+        check_assist(
+            move_module_to_file,
+            r#"
+mod $0tests {
+    #[test] fn t() {}
+}
+"#,
+            r#"
+//- /main.rs
+mod tests;
+//- /tests.rs
+#[test] fn t() {}
+"#,
+        );
+    }
+
+    #[test]
+    fn extract_from_submodule() {
+        check_assist(
+            move_module_to_file,
+            r#"
+//- /main.rs
+mod submod;
+//- /submod.rs
+$0mod inner {
+    fn f() {}
+}
+fn g() {}
+"#,
+            r#"
+//- /submod.rs
+mod inner;
+fn g() {}
+//- /submod/inner.rs
+fn f() {}
+"#,
+        );
+    }
+
+    #[test]
+    fn extract_from_mod_rs() {
+        check_assist(
+            move_module_to_file,
+            r#"
+//- /main.rs
+mod submodule;
+//- /submodule/mod.rs
+mod inner$0 {
+    fn f() {}
+}
+fn g() {}
+"#,
+            r#"
+//- /submodule/mod.rs
+mod inner;
+fn g() {}
+//- /submodule/inner.rs
+fn f() {}
+"#,
+        );
+    }
+
+    #[test]
+    fn extract_public() {
+        check_assist(
+            move_module_to_file,
+            r#"
+pub mod $0tests {
+    #[test] fn t() {}
+}
+"#,
+            r#"
+//- /main.rs
+pub mod tests;
+//- /tests.rs
+#[test] fn t() {}
+"#,
+        );
+    }
+
+    #[test]
+    fn extract_public_crate() {
+        check_assist(
+            move_module_to_file,
+            r#"
+pub(crate) mod $0tests {
+    #[test] fn t() {}
+}
+"#,
+            r#"
+//- /main.rs
+pub(crate) mod tests;
+//- /tests.rs
+#[test] fn t() {}
+"#,
+        );
+    }
+
+    #[test]
+    fn available_before_curly() {
+        mark::check!(available_before_curly);
+        check_assist_not_applicable(move_module_to_file, r#"mod m { $0 }"#);
+    }
+}
diff --git a/crates/ide_assists/src/handlers/pull_assignment_up.rs b/crates/ide_assists/src/handlers/pull_assignment_up.rs
new file mode 100644
index 000000000..13e1cb754
--- /dev/null
+++ b/crates/ide_assists/src/handlers/pull_assignment_up.rs
@@ -0,0 +1,400 @@
+use syntax::{
+    ast::{self, edit::AstNodeEdit, make},
+    AstNode,
+};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind,
+};
+
+// Assist: pull_assignment_up
+//
+// Extracts variable assignment to outside an if or match statement.
+//
+// ```
+// fn main() {
+//     let mut foo = 6;
+//
+//     if true {
+//         $0foo = 5;
+//     } else {
+//         foo = 4;
+//     }
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     let mut foo = 6;
+//
+//     foo = if true {
+//         5
+//     } else {
+//         4
+//     };
+// }
+// ```
+pub(crate) fn pull_assignment_up(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let assign_expr = ctx.find_node_at_offset::<ast::BinExpr>()?;
+    let name_expr = if assign_expr.op_kind()? == ast::BinOp::Assignment {
+        assign_expr.lhs()?
+    } else {
+        return None;
+    };
+
+    let (old_stmt, new_stmt) = if let Some(if_expr) = ctx.find_node_at_offset::<ast::IfExpr>() {
+        (
+            ast::Expr::cast(if_expr.syntax().to_owned())?,
+            exprify_if(&if_expr, &ctx.sema, &name_expr)?.indent(if_expr.indent_level()),
+        )
+    } else if let Some(match_expr) = ctx.find_node_at_offset::<ast::MatchExpr>() {
+        (
+            ast::Expr::cast(match_expr.syntax().to_owned())?,
+            exprify_match(&match_expr, &ctx.sema, &name_expr)?,
+        )
+    } else {
+        return None;
+    };
+
+    let expr_stmt = make::expr_stmt(new_stmt);
+
+    acc.add(
+        AssistId("pull_assignment_up", AssistKind::RefactorExtract),
+        "Pull assignment up",
+        old_stmt.syntax().text_range(),
+        move |edit| {
+            edit.replace(old_stmt.syntax().text_range(), format!("{} = {};", name_expr, expr_stmt));
+        },
+    )
+}
+
+fn exprify_match(
+    match_expr: &ast::MatchExpr,
+    sema: &hir::Semantics<ide_db::RootDatabase>,
+    name: &ast::Expr,
+) -> Option<ast::Expr> {
+    let new_arm_list = match_expr
+        .match_arm_list()?
+        .arms()
+        .map(|arm| {
+            if let ast::Expr::BlockExpr(block) = arm.expr()? {
+                let new_block = exprify_block(&block, sema, name)?.indent(block.indent_level());
+                Some(arm.replace_descendant(block, new_block))
+            } else {
+                None
+            }
+        })
+        .collect::<Option<Vec<_>>>()?;
+    let new_arm_list = match_expr
+        .match_arm_list()?
+        .replace_descendants(match_expr.match_arm_list()?.arms().zip(new_arm_list));
+    Some(make::expr_match(match_expr.expr()?, new_arm_list))
+}
+
+fn exprify_if(
+    statement: &ast::IfExpr,
+    sema: &hir::Semantics<ide_db::RootDatabase>,
+    name: &ast::Expr,
+) -> Option<ast::Expr> {
+    let then_branch = exprify_block(&statement.then_branch()?, sema, name)?;
+    let else_branch = match statement.else_branch()? {
+        ast::ElseBranch::Block(ref block) => {
+            ast::ElseBranch::Block(exprify_block(block, sema, name)?)
+        }
+        ast::ElseBranch::IfExpr(expr) => {
+            mark::hit!(test_pull_assignment_up_chained_if);
+            ast::ElseBranch::IfExpr(ast::IfExpr::cast(
+                exprify_if(&expr, sema, name)?.syntax().to_owned(),
+            )?)
+        }
+    };
+    Some(make::expr_if(statement.condition()?, then_branch, Some(else_branch)))
+}
+
+fn exprify_block(
+    block: &ast::BlockExpr,
+    sema: &hir::Semantics<ide_db::RootDatabase>,
+    name: &ast::Expr,
+) -> Option<ast::BlockExpr> {
+    if block.tail_expr().is_some() {
+        return None;
+    }
+
+    let mut stmts: Vec<_> = block.statements().collect();
+    let stmt = stmts.pop()?;
+
+    if let ast::Stmt::ExprStmt(stmt) = stmt {
+        if let ast::Expr::BinExpr(expr) = stmt.expr()? {
+            if expr.op_kind()? == ast::BinOp::Assignment && is_equivalent(sema, &expr.lhs()?, name)
+            {
+                // The last statement in the block is an assignment to the name we want
+                return Some(make::block_expr(stmts, Some(expr.rhs()?)));
+            }
+        }
+    }
+    None
+}
+
+fn is_equivalent(
+    sema: &hir::Semantics<ide_db::RootDatabase>,
+    expr0: &ast::Expr,
+    expr1: &ast::Expr,
+) -> bool {
+    match (expr0, expr1) {
+        (ast::Expr::FieldExpr(field_expr0), ast::Expr::FieldExpr(field_expr1)) => {
+            mark::hit!(test_pull_assignment_up_field_assignment);
+            sema.resolve_field(field_expr0) == sema.resolve_field(field_expr1)
+        }
+        (ast::Expr::PathExpr(path0), ast::Expr::PathExpr(path1)) => {
+            let path0 = path0.path();
+            let path1 = path1.path();
+            if let (Some(path0), Some(path1)) = (path0, path1) {
+                sema.resolve_path(&path0) == sema.resolve_path(&path1)
+            } else {
+                false
+            }
+        }
+        _ => false,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    #[test]
+    fn test_pull_assignment_up_if() {
+        check_assist(
+            pull_assignment_up,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    if true {
+        $0a = 2;
+    } else {
+        a = 3;
+    }
+}"#,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    a = if true {
+        2
+    } else {
+        3
+    };
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_pull_assignment_up_match() {
+        check_assist(
+            pull_assignment_up,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    match 1 {
+        1 => {
+            $0a = 2;
+        },
+        2 => {
+            a = 3;
+        },
+        3 => {
+            a = 4;
+        }
+    }
+}"#,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    a = match 1 {
+        1 => {
+            2
+        },
+        2 => {
+            3
+        },
+        3 => {
+            4
+        }
+    };
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_pull_assignment_up_not_last_not_applicable() {
+        check_assist_not_applicable(
+            pull_assignment_up,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    if true {
+        $0a = 2;
+        b = a;
+    } else {
+        a = 3;
+    }
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_pull_assignment_up_chained_if() {
+        mark::check!(test_pull_assignment_up_chained_if);
+        check_assist(
+            pull_assignment_up,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    if true {
+        $0a = 2;
+    } else if false {
+        a = 3;
+    } else {
+        a = 4;
+    }
+}"#,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    a = if true {
+        2
+    } else if false {
+        3
+    } else {
+        4
+    };
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_pull_assignment_up_retains_stmts() {
+        check_assist(
+            pull_assignment_up,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    if true {
+        let b = 2;
+        $0a = 2;
+    } else {
+        let b = 3;
+        a = 3;
+    }
+}"#,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    a = if true {
+        let b = 2;
+        2
+    } else {
+        let b = 3;
+        3
+    };
+}"#,
+        )
+    }
+
+    #[test]
+    fn pull_assignment_up_let_stmt_not_applicable() {
+        check_assist_not_applicable(
+            pull_assignment_up,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    let b = if true {
+        $0a = 2
+    } else {
+        a = 3
+    };
+}"#,
+        )
+    }
+
+    #[test]
+    fn pull_assignment_up_if_missing_assigment_not_applicable() {
+        check_assist_not_applicable(
+            pull_assignment_up,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    if true {
+        $0a = 2;
+    } else {}
+}"#,
+        )
+    }
+
+    #[test]
+    fn pull_assignment_up_match_missing_assigment_not_applicable() {
+        check_assist_not_applicable(
+            pull_assignment_up,
+            r#"
+fn foo() {
+    let mut a = 1;
+
+    match 1 {
+        1 => {
+            $0a = 2;
+        },
+        2 => {
+            a = 3;
+        },
+        3 => {},
+    }
+}"#,
+        )
+    }
+
+    #[test]
+    fn test_pull_assignment_up_field_assignment() {
+        mark::check!(test_pull_assignment_up_field_assignment);
+        check_assist(
+            pull_assignment_up,
+            r#"
+struct A(usize);
+
+fn foo() {
+    let mut a = A(1);
+
+    if true {
+        $0a.0 = 2;
+    } else {
+        a.0 = 3;
+    }
+}"#,
+            r#"
+struct A(usize);
+
+fn foo() {
+    let mut a = A(1);
+
+    a.0 = if true {
+        2
+    } else {
+        3
+    };
+}"#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/qualify_path.rs b/crates/ide_assists/src/handlers/qualify_path.rs
new file mode 100644
index 000000000..b0b0d31b4
--- /dev/null
+++ b/crates/ide_assists/src/handlers/qualify_path.rs
@@ -0,0 +1,1205 @@
+use std::iter;
+
+use hir::{AsAssocItem, AsName};
+use ide_db::helpers::{import_assets::ImportCandidate, mod_path_to_ast};
+use ide_db::RootDatabase;
+use syntax::{
+    ast,
+    ast::{make, ArgListOwner},
+    AstNode,
+};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind, GroupLabel,
+};
+
+use super::auto_import::find_importable_node;
+
+// Assist: qualify_path
+//
+// If the name is unresolved, provides all possible qualified paths for it.
+//
+// ```
+// fn main() {
+//     let map = HashMap$0::new();
+// }
+// # pub mod std { pub mod collections { pub struct HashMap { } } }
+// ```
+// ->
+// ```
+// fn main() {
+//     let map = std::collections::HashMap::new();
+// }
+// # pub mod std { pub mod collections { pub struct HashMap { } } }
+// ```
+pub(crate) fn qualify_path(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let (import_assets, syntax_under_caret) = find_importable_node(ctx)?;
+    let proposed_imports = import_assets.search_for_relative_paths(&ctx.sema);
+    if proposed_imports.is_empty() {
+        return None;
+    }
+
+    let candidate = import_assets.import_candidate();
+    let range = ctx.sema.original_range(&syntax_under_caret).range;
+
+    let qualify_candidate = match candidate {
+        ImportCandidate::Path(candidate) => {
+            if candidate.qualifier.is_some() {
+                mark::hit!(qualify_path_qualifier_start);
+                let path = ast::Path::cast(syntax_under_caret)?;
+                let (prev_segment, segment) = (path.qualifier()?.segment()?, path.segment()?);
+                QualifyCandidate::QualifierStart(segment, prev_segment.generic_arg_list())
+            } else {
+                mark::hit!(qualify_path_unqualified_name);
+                let path = ast::Path::cast(syntax_under_caret)?;
+                let generics = path.segment()?.generic_arg_list();
+                QualifyCandidate::UnqualifiedName(generics)
+            }
+        }
+        ImportCandidate::TraitAssocItem(_) => {
+            mark::hit!(qualify_path_trait_assoc_item);
+            let path = ast::Path::cast(syntax_under_caret)?;
+            let (qualifier, segment) = (path.qualifier()?, path.segment()?);
+            QualifyCandidate::TraitAssocItem(qualifier, segment)
+        }
+        ImportCandidate::TraitMethod(_) => {
+            mark::hit!(qualify_path_trait_method);
+            let mcall_expr = ast::MethodCallExpr::cast(syntax_under_caret)?;
+            QualifyCandidate::TraitMethod(ctx.sema.db, mcall_expr)
+        }
+    };
+
+    let group_label = group_label(candidate);
+    for (import, item) in proposed_imports {
+        acc.add_group(
+            &group_label,
+            AssistId("qualify_path", AssistKind::QuickFix),
+            label(candidate, &import),
+            range,
+            |builder| {
+                qualify_candidate.qualify(
+                    |replace_with: String| builder.replace(range, replace_with),
+                    import,
+                    item,
+                )
+            },
+        );
+    }
+    Some(())
+}
+
+enum QualifyCandidate<'db> {
+    QualifierStart(ast::PathSegment, Option<ast::GenericArgList>),
+    UnqualifiedName(Option<ast::GenericArgList>),
+    TraitAssocItem(ast::Path, ast::PathSegment),
+    TraitMethod(&'db RootDatabase, ast::MethodCallExpr),
+}
+
+impl QualifyCandidate<'_> {
+    fn qualify(&self, mut replacer: impl FnMut(String), import: hir::ModPath, item: hir::ItemInNs) {
+        let import = mod_path_to_ast(&import);
+        match self {
+            QualifyCandidate::QualifierStart(segment, generics) => {
+                let generics = generics.as_ref().map_or_else(String::new, ToString::to_string);
+                replacer(format!("{}{}::{}", import, generics, segment));
+            }
+            QualifyCandidate::UnqualifiedName(generics) => {
+                let generics = generics.as_ref().map_or_else(String::new, ToString::to_string);
+                replacer(format!("{}{}", import.to_string(), generics));
+            }
+            QualifyCandidate::TraitAssocItem(qualifier, segment) => {
+                replacer(format!("<{} as {}>::{}", qualifier, import, segment));
+            }
+            &QualifyCandidate::TraitMethod(db, ref mcall_expr) => {
+                Self::qualify_trait_method(db, mcall_expr, replacer, import, item);
+            }
+        }
+    }
+
+    fn qualify_trait_method(
+        db: &RootDatabase,
+        mcall_expr: &ast::MethodCallExpr,
+        mut replacer: impl FnMut(String),
+        import: ast::Path,
+        item: hir::ItemInNs,
+    ) -> Option<()> {
+        let receiver = mcall_expr.receiver()?;
+        let trait_method_name = mcall_expr.name_ref()?;
+        let generics =
+            mcall_expr.generic_arg_list().as_ref().map_or_else(String::new, ToString::to_string);
+        let arg_list = mcall_expr.arg_list().map(|arg_list| arg_list.args());
+        let trait_ = item_as_trait(db, item)?;
+        let method = find_trait_method(db, trait_, &trait_method_name)?;
+        if let Some(self_access) = method.self_param(db).map(|sp| sp.access(db)) {
+            let receiver = match self_access {
+                hir::Access::Shared => make::expr_ref(receiver, false),
+                hir::Access::Exclusive => make::expr_ref(receiver, true),
+                hir::Access::Owned => receiver,
+            };
+            replacer(format!(
+                "{}::{}{}{}",
+                import,
+                trait_method_name,
+                generics,
+                match arg_list {
+                    Some(args) => make::arg_list(iter::once(receiver).chain(args)),
+                    None => make::arg_list(iter::once(receiver)),
+                }
+            ));
+        }
+        Some(())
+    }
+}
+
+fn find_trait_method(
+    db: &RootDatabase,
+    trait_: hir::Trait,
+    trait_method_name: &ast::NameRef,
+) -> Option<hir::Function> {
+    if let Some(hir::AssocItem::Function(method)) =
+        trait_.items(db).into_iter().find(|item: &hir::AssocItem| {
+            item.name(db).map(|name| name == trait_method_name.as_name()).unwrap_or(false)
+        })
+    {
+        Some(method)
+    } else {
+        None
+    }
+}
+
+fn item_as_trait(db: &RootDatabase, item: hir::ItemInNs) -> Option<hir::Trait> {
+    let item_module_def = hir::ModuleDef::from(item.as_module_def_id()?);
+
+    if let hir::ModuleDef::Trait(trait_) = item_module_def {
+        Some(trait_)
+    } else {
+        item_module_def.as_assoc_item(db)?.containing_trait(db)
+    }
+}
+
+fn group_label(candidate: &ImportCandidate) -> GroupLabel {
+    let name = match candidate {
+        ImportCandidate::Path(it) => &it.name,
+        ImportCandidate::TraitAssocItem(it) | ImportCandidate::TraitMethod(it) => &it.name,
+    }
+    .text();
+    GroupLabel(format!("Qualify {}", name))
+}
+
+fn label(candidate: &ImportCandidate, import: &hir::ModPath) -> String {
+    match candidate {
+        ImportCandidate::Path(candidate) => {
+            if candidate.qualifier.is_some() {
+                format!("Qualify with `{}`", &import)
+            } else {
+                format!("Qualify as `{}`", &import)
+            }
+        }
+        ImportCandidate::TraitAssocItem(_) => format!("Qualify `{}`", &import),
+        ImportCandidate::TraitMethod(_) => format!("Qualify with cast as `{}`", &import),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn applicable_when_found_an_import_partial() {
+        mark::check!(qualify_path_unqualified_name);
+        check_assist(
+            qualify_path,
+            r"
+            mod std {
+                pub mod fmt {
+                    pub struct Formatter;
+                }
+            }
+
+            use std::fmt;
+
+            $0Formatter
+            ",
+            r"
+            mod std {
+                pub mod fmt {
+                    pub struct Formatter;
+                }
+            }
+
+            use std::fmt;
+
+            fmt::Formatter
+            ",
+        );
+    }
+
+    #[test]
+    fn applicable_when_found_an_import() {
+        check_assist(
+            qualify_path,
+            r"
+            $0PubStruct
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            PubMod::PubStruct
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn applicable_in_macros() {
+        check_assist(
+            qualify_path,
+            r"
+            macro_rules! foo {
+                ($i:ident) => { fn foo(a: $i) {} }
+            }
+            foo!(Pub$0Struct);
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            macro_rules! foo {
+                ($i:ident) => { fn foo(a: $i) {} }
+            }
+            foo!(PubMod::PubStruct);
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn applicable_when_found_multiple_imports() {
+        check_assist(
+            qualify_path,
+            r"
+            PubSt$0ruct
+
+            pub mod PubMod1 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod2 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod3 {
+                pub struct PubStruct;
+            }
+            ",
+            r"
+            PubMod3::PubStruct
+
+            pub mod PubMod1 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod2 {
+                pub struct PubStruct;
+            }
+            pub mod PubMod3 {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_already_imported_types() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            use PubMod::PubStruct;
+
+            PubStruct$0
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_types_with_private_paths() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            PrivateStruct$0
+
+            pub mod PubMod {
+                struct PrivateStruct;
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_when_no_imports_found() {
+        check_assist_not_applicable(
+            qualify_path,
+            "
+            PubStruct$0",
+        );
+    }
+
+    #[test]
+    fn not_applicable_in_import_statements() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            use PubStruct$0;
+
+            pub mod PubMod {
+                pub struct PubStruct;
+            }",
+        );
+    }
+
+    #[test]
+    fn qualify_function() {
+        check_assist(
+            qualify_path,
+            r"
+            test_function$0
+
+            pub mod PubMod {
+                pub fn test_function() {};
+            }
+            ",
+            r"
+            PubMod::test_function
+
+            pub mod PubMod {
+                pub fn test_function() {};
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn qualify_macro() {
+        check_assist(
+            qualify_path,
+            r"
+//- /lib.rs crate:crate_with_macro
+#[macro_export]
+macro_rules! foo {
+    () => ()
+}
+
+//- /main.rs crate:main deps:crate_with_macro
+fn main() {
+    foo$0
+}
+",
+            r"
+fn main() {
+    crate_with_macro::foo
+}
+",
+        );
+    }
+
+    #[test]
+    fn qualify_path_target() {
+        check_assist_target(
+            qualify_path,
+            r"
+            struct AssistInfo {
+                group_label: Option<$0GroupLabel>,
+            }
+
+            mod m { pub struct GroupLabel; }
+            ",
+            "GroupLabel",
+        )
+    }
+
+    #[test]
+    fn not_applicable_when_path_start_is_imported() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            pub mod mod1 {
+                pub mod mod2 {
+                    pub mod mod3 {
+                        pub struct TestStruct;
+                    }
+                }
+            }
+
+            use mod1::mod2;
+            fn main() {
+                mod2::mod3::TestStruct$0
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_function() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            pub mod test_mod {
+                pub fn test_function() {}
+            }
+
+            use test_mod::test_function;
+            fn main() {
+                test_function$0
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_struct_function() {
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    pub fn test_function() {}
+                }
+            }
+
+            fn main() {
+                TestStruct::test_function$0
+            }
+            ",
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    pub fn test_function() {}
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_struct_const() {
+        mark::check!(qualify_path_qualifier_start);
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                TestStruct::TEST_CONST$0
+            }
+            ",
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::TEST_CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_trait_function() {
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::test_function$0
+            }
+            ",
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+
+            fn main() {
+                <test_mod::TestStruct as test_mod::TestTrait>::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_function() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub trait TestTrait2 {
+                    fn test_function();
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    fn test_function() {}
+                }
+                impl TestTrait for TestEnum {
+                    fn test_function() {}
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                test_mod::TestEnum::test_function$0;
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn associated_trait_const() {
+        mark::check!(qualify_path_trait_assoc_item);
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::TEST_CONST$0
+            }
+            ",
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                <test_mod::TestStruct as test_mod::TestTrait>::TEST_CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_const() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub trait TestTrait2 {
+                    const TEST_CONST: f64;
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    const TEST_CONST: f64 = 42.0;
+                }
+                impl TestTrait for TestEnum {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                test_mod::TestEnum::TEST_CONST$0;
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn trait_method() {
+        mark::check!(qualify_path_trait_method);
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_meth$0od()
+            }
+            ",
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_mod::TestTrait::test_method(&test_struct)
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn trait_method_multi_params() {
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self, test: i32);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self, test: i32) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_meth$0od(42)
+            }
+            ",
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self, test: i32);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self, test: i32) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_mod::TestTrait::test_method(&test_struct, 42)
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn trait_method_consume() {
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_meth$0od()
+            }
+            ",
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_mod::TestTrait::test_method(test_struct)
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn trait_method_cross_crate() {
+        check_assist(
+            qualify_path,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_meth$0od()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+            ",
+            r"
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                dep::test_mod::TestTrait::test_method(&test_struct)
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_fn_cross_crate() {
+        check_assist(
+            qualify_path,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                dep::test_mod::TestStruct::test_func$0tion
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+            ",
+            r"
+            fn main() {
+                <dep::test_mod::TestStruct as dep::test_mod::TestTrait>::test_function
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_const_cross_crate() {
+        check_assist(
+            qualify_path,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                dep::test_mod::TestStruct::CONST$0
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    const CONST: bool;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const CONST: bool = true;
+                }
+            }
+            ",
+            r"
+            fn main() {
+                <dep::test_mod::TestStruct as dep::test_mod::TestTrait>::CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn assoc_fn_as_method_cross_crate() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_func$0tion()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn private_trait_cross_crate() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            //- /main.rs crate:main deps:dep
+            fn main() {
+                let test_struct = dep::test_mod::TestStruct {};
+                test_struct.test_meth$0od()
+            }
+            //- /dep.rs crate:dep
+            pub mod test_mod {
+                trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_method() {
+        check_assist_not_applicable(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub trait TestTrait2 {
+                    fn test_method(&self);
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    fn test_method(&self) {}
+                }
+                impl TestTrait for TestEnum {
+                    fn test_method(&self) {}
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                let one = test_mod::TestEnum::One;
+                one.test$0_method();
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn dep_import() {
+        check_assist(
+            qualify_path,
+            r"
+//- /lib.rs crate:dep
+pub struct Struct;
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    Struct$0
+}
+",
+            r"
+fn main() {
+    dep::Struct
+}
+",
+        );
+    }
+
+    #[test]
+    fn whole_segment() {
+        // Tests that only imports whose last segment matches the identifier get suggested.
+        check_assist(
+            qualify_path,
+            r"
+//- /lib.rs crate:dep
+pub mod fmt {
+    pub trait Display {}
+}
+
+pub fn panic_fmt() {}
+
+//- /main.rs crate:main deps:dep
+struct S;
+
+impl f$0mt::Display for S {}
+",
+            r"
+struct S;
+
+impl dep::fmt::Display for S {}
+",
+        );
+    }
+
+    #[test]
+    fn macro_generated() {
+        // Tests that macro-generated items are suggested from external crates.
+        check_assist(
+            qualify_path,
+            r"
+//- /lib.rs crate:dep
+macro_rules! mac {
+    () => {
+        pub struct Cheese;
+    };
+}
+
+mac!();
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    Cheese$0;
+}
+",
+            r"
+fn main() {
+    dep::Cheese;
+}
+",
+        );
+    }
+
+    #[test]
+    fn casing() {
+        // Tests that differently cased names don't interfere and we only suggest the matching one.
+        check_assist(
+            qualify_path,
+            r"
+//- /lib.rs crate:dep
+pub struct FMT;
+pub struct fmt;
+
+//- /main.rs crate:main deps:dep
+fn main() {
+    FMT$0;
+}
+",
+            r"
+fn main() {
+    dep::FMT;
+}
+",
+        );
+    }
+
+    #[test]
+    fn keep_generic_annotations() {
+        check_assist(
+            qualify_path,
+            r"
+//- /lib.rs crate:dep
+pub mod generic { pub struct Thing<'a, T>(&'a T); }
+
+//- /main.rs crate:main deps:dep
+fn foo() -> Thin$0g<'static, ()> {}
+
+fn main() {}
+",
+            r"
+fn foo() -> dep::generic::Thing<'static, ()> {}
+
+fn main() {}
+",
+        );
+    }
+
+    #[test]
+    fn keep_generic_annotations_leading_colon() {
+        check_assist(
+            qualify_path,
+            r"
+//- /lib.rs crate:dep
+pub mod generic { pub struct Thing<'a, T>(&'a T); }
+
+//- /main.rs crate:main deps:dep
+fn foo() -> Thin$0g::<'static, ()> {}
+
+fn main() {}
+",
+            r"
+fn foo() -> dep::generic::Thing::<'static, ()> {}
+
+fn main() {}
+",
+        );
+    }
+
+    #[test]
+    fn associated_struct_const_generic() {
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub struct TestStruct<T> {}
+                impl<T> TestStruct<T> {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                TestStruct::<()>::TEST_CONST$0
+            }
+            ",
+            r"
+            mod test_mod {
+                pub struct TestStruct<T> {}
+                impl<T> TestStruct<T> {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::<()>::TEST_CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_trait_const_generic() {
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct<T> {}
+                impl<T> TestTrait for TestStruct<T> {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::<()>::TEST_CONST$0
+            }
+            ",
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct<T> {}
+                impl<T> TestTrait for TestStruct<T> {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                <test_mod::TestStruct::<()> as test_mod::TestTrait>::TEST_CONST
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn trait_method_generic() {
+        check_assist(
+            qualify_path,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method<T>(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method<T>(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_meth$0od::<()>()
+            }
+            ",
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method<T>(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method<T>(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_mod::TestTrait::test_method::<()>(&test_struct)
+            }
+            ",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/raw_string.rs b/crates/ide_assists/src/handlers/raw_string.rs
new file mode 100644
index 000000000..d95267607
--- /dev/null
+++ b/crates/ide_assists/src/handlers/raw_string.rs
@@ -0,0 +1,512 @@
+use std::borrow::Cow;
+
+use syntax::{ast, AstToken, TextRange, TextSize};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: make_raw_string
+//
+// Adds `r#` to a plain string literal.
+//
+// ```
+// fn main() {
+//     "Hello,$0 World!";
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r#"Hello, World!"#;
+// }
+// ```
+pub(crate) fn make_raw_string(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let token = ctx.find_token_at_offset::<ast::String>()?;
+    if token.is_raw() {
+        return None;
+    }
+    let value = token.value()?;
+    let target = token.syntax().text_range();
+    acc.add(
+        AssistId("make_raw_string", AssistKind::RefactorRewrite),
+        "Rewrite as raw string",
+        target,
+        |edit| {
+            let hashes = "#".repeat(required_hashes(&value).max(1));
+            if matches!(value, Cow::Borrowed(_)) {
+                // Avoid replacing the whole string to better position the cursor.
+                edit.insert(token.syntax().text_range().start(), format!("r{}", hashes));
+                edit.insert(token.syntax().text_range().end(), format!("{}", hashes));
+            } else {
+                edit.replace(
+                    token.syntax().text_range(),
+                    format!("r{}\"{}\"{}", hashes, value, hashes),
+                );
+            }
+        },
+    )
+}
+
+// Assist: make_usual_string
+//
+// Turns a raw string into a plain string.
+//
+// ```
+// fn main() {
+//     r#"Hello,$0 "World!""#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     "Hello, \"World!\"";
+// }
+// ```
+pub(crate) fn make_usual_string(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let token = ctx.find_token_at_offset::<ast::String>()?;
+    if !token.is_raw() {
+        return None;
+    }
+    let value = token.value()?;
+    let target = token.syntax().text_range();
+    acc.add(
+        AssistId("make_usual_string", AssistKind::RefactorRewrite),
+        "Rewrite as regular string",
+        target,
+        |edit| {
+            // parse inside string to escape `"`
+            let escaped = value.escape_default().to_string();
+            if let Some(offsets) = token.quote_offsets() {
+                if token.text()[offsets.contents - token.syntax().text_range().start()] == escaped {
+                    edit.replace(offsets.quotes.0, "\"");
+                    edit.replace(offsets.quotes.1, "\"");
+                    return;
+                }
+            }
+
+            edit.replace(token.syntax().text_range(), format!("\"{}\"", escaped));
+        },
+    )
+}
+
+// Assist: add_hash
+//
+// Adds a hash to a raw string literal.
+//
+// ```
+// fn main() {
+//     r#"Hello,$0 World!"#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r##"Hello, World!"##;
+// }
+// ```
+pub(crate) fn add_hash(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let token = ctx.find_token_at_offset::<ast::String>()?;
+    if !token.is_raw() {
+        return None;
+    }
+    let text_range = token.syntax().text_range();
+    let target = text_range;
+    acc.add(AssistId("add_hash", AssistKind::Refactor), "Add #", target, |edit| {
+        edit.insert(text_range.start() + TextSize::of('r'), "#");
+        edit.insert(text_range.end(), "#");
+    })
+}
+
+// Assist: remove_hash
+//
+// Removes a hash from a raw string literal.
+//
+// ```
+// fn main() {
+//     r#"Hello,$0 World!"#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r"Hello, World!";
+// }
+// ```
+pub(crate) fn remove_hash(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let token = ctx.find_token_at_offset::<ast::String>()?;
+    if !token.is_raw() {
+        return None;
+    }
+
+    let text = token.text();
+    if !text.starts_with("r#") && text.ends_with('#') {
+        return None;
+    }
+
+    let existing_hashes = text.chars().skip(1).take_while(|&it| it == '#').count();
+
+    let text_range = token.syntax().text_range();
+    let internal_text = &text[token.text_range_between_quotes()? - text_range.start()];
+
+    if existing_hashes == required_hashes(internal_text) {
+        mark::hit!(cant_remove_required_hash);
+        return None;
+    }
+
+    acc.add(AssistId("remove_hash", AssistKind::RefactorRewrite), "Remove #", text_range, |edit| {
+        edit.delete(TextRange::at(text_range.start() + TextSize::of('r'), TextSize::of('#')));
+        edit.delete(TextRange::new(text_range.end() - TextSize::of('#'), text_range.end()));
+    })
+}
+
+fn required_hashes(s: &str) -> usize {
+    let mut res = 0usize;
+    for idx in s.match_indices('"').map(|(i, _)| i) {
+        let (_, sub) = s.split_at(idx + 1);
+        let n_hashes = sub.chars().take_while(|c| *c == '#').count();
+        res = res.max(n_hashes + 1)
+    }
+    res
+}
+
+#[test]
+fn test_required_hashes() {
+    assert_eq!(0, required_hashes("abc"));
+    assert_eq!(0, required_hashes("###"));
+    assert_eq!(1, required_hashes("\""));
+    assert_eq!(2, required_hashes("\"#abc"));
+    assert_eq!(0, required_hashes("#abc"));
+    assert_eq!(3, required_hashes("#ab\"##c"));
+    assert_eq!(5, required_hashes("#ab\"##\"####c"));
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn make_raw_string_target() {
+        check_assist_target(
+            make_raw_string,
+            r#"
+            fn f() {
+                let s = $0"random\nstring";
+            }
+            "#,
+            r#""random\nstring""#,
+        );
+    }
+
+    #[test]
+    fn make_raw_string_works() {
+        check_assist(
+            make_raw_string,
+            r#"
+fn f() {
+    let s = $0"random\nstring";
+}
+"#,
+            r##"
+fn f() {
+    let s = r#"random
+string"#;
+}
+"##,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_works_inside_macros() {
+        check_assist(
+            make_raw_string,
+            r#"
+            fn f() {
+                format!($0"x = {}", 92)
+            }
+            "#,
+            r##"
+            fn f() {
+                format!(r#"x = {}"#, 92)
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_hashes_inside_works() {
+        check_assist(
+            make_raw_string,
+            r###"
+fn f() {
+    let s = $0"#random##\nstring";
+}
+"###,
+            r####"
+fn f() {
+    let s = r#"#random##
+string"#;
+}
+"####,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_closing_hashes_inside_works() {
+        check_assist(
+            make_raw_string,
+            r###"
+fn f() {
+    let s = $0"#random\"##\nstring";
+}
+"###,
+            r####"
+fn f() {
+    let s = r###"#random"##
+string"###;
+}
+"####,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_nothing_to_unescape_works() {
+        check_assist(
+            make_raw_string,
+            r#"
+            fn f() {
+                let s = $0"random string";
+            }
+            "#,
+            r##"
+            fn f() {
+                let s = r#"random string"#;
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn make_raw_string_not_works_on_partial_string() {
+        check_assist_not_applicable(
+            make_raw_string,
+            r#"
+            fn f() {
+                let s = "foo$0
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn make_usual_string_not_works_on_partial_string() {
+        check_assist_not_applicable(
+            make_usual_string,
+            r#"
+            fn main() {
+                let s = r#"bar$0
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn add_hash_target() {
+        check_assist_target(
+            add_hash,
+            r#"
+            fn f() {
+                let s = $0r"random string";
+            }
+            "#,
+            r#"r"random string""#,
+        );
+    }
+
+    #[test]
+    fn add_hash_works() {
+        check_assist(
+            add_hash,
+            r#"
+            fn f() {
+                let s = $0r"random string";
+            }
+            "#,
+            r##"
+            fn f() {
+                let s = r#"random string"#;
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn add_more_hash_works() {
+        check_assist(
+            add_hash,
+            r##"
+            fn f() {
+                let s = $0r#"random"string"#;
+            }
+            "##,
+            r###"
+            fn f() {
+                let s = r##"random"string"##;
+            }
+            "###,
+        )
+    }
+
+    #[test]
+    fn add_hash_not_works() {
+        check_assist_not_applicable(
+            add_hash,
+            r#"
+            fn f() {
+                let s = $0"random string";
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn remove_hash_target() {
+        check_assist_target(
+            remove_hash,
+            r##"
+            fn f() {
+                let s = $0r#"random string"#;
+            }
+            "##,
+            r##"r#"random string"#"##,
+        );
+    }
+
+    #[test]
+    fn remove_hash_works() {
+        check_assist(
+            remove_hash,
+            r##"fn f() { let s = $0r#"random string"#; }"##,
+            r#"fn f() { let s = r"random string"; }"#,
+        )
+    }
+
+    #[test]
+    fn cant_remove_required_hash() {
+        mark::check!(cant_remove_required_hash);
+        check_assist_not_applicable(
+            remove_hash,
+            r##"
+            fn f() {
+                let s = $0r#"random"str"ing"#;
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn remove_more_hash_works() {
+        check_assist(
+            remove_hash,
+            r###"
+            fn f() {
+                let s = $0r##"random string"##;
+            }
+            "###,
+            r##"
+            fn f() {
+                let s = r#"random string"#;
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn remove_hash_doesnt_work() {
+        check_assist_not_applicable(remove_hash, r#"fn f() { let s = $0"random string"; }"#);
+    }
+
+    #[test]
+    fn remove_hash_no_hash_doesnt_work() {
+        check_assist_not_applicable(remove_hash, r#"fn f() { let s = $0r"random string"; }"#);
+    }
+
+    #[test]
+    fn make_usual_string_target() {
+        check_assist_target(
+            make_usual_string,
+            r##"
+            fn f() {
+                let s = $0r#"random string"#;
+            }
+            "##,
+            r##"r#"random string"#"##,
+        );
+    }
+
+    #[test]
+    fn make_usual_string_works() {
+        check_assist(
+            make_usual_string,
+            r##"
+            fn f() {
+                let s = $0r#"random string"#;
+            }
+            "##,
+            r#"
+            fn f() {
+                let s = "random string";
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn make_usual_string_with_quote_works() {
+        check_assist(
+            make_usual_string,
+            r##"
+            fn f() {
+                let s = $0r#"random"str"ing"#;
+            }
+            "##,
+            r#"
+            fn f() {
+                let s = "random\"str\"ing";
+            }
+            "#,
+        )
+    }
+
+    #[test]
+    fn make_usual_string_more_hash_works() {
+        check_assist(
+            make_usual_string,
+            r###"
+            fn f() {
+                let s = $0r##"random string"##;
+            }
+            "###,
+            r##"
+            fn f() {
+                let s = "random string";
+            }
+            "##,
+        )
+    }
+
+    #[test]
+    fn make_usual_string_not_works() {
+        check_assist_not_applicable(
+            make_usual_string,
+            r#"
+            fn f() {
+                let s = $0"random string";
+            }
+            "#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/remove_dbg.rs b/crates/ide_assists/src/handlers/remove_dbg.rs
new file mode 100644
index 000000000..6114091f2
--- /dev/null
+++ b/crates/ide_assists/src/handlers/remove_dbg.rs
@@ -0,0 +1,421 @@
+use syntax::{
+    ast::{self, AstNode},
+    match_ast, SyntaxElement, TextRange, TextSize, T,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: remove_dbg
+//
+// Removes `dbg!()` macro call.
+//
+// ```
+// fn main() {
+//     $0dbg!(92);
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     92;
+// }
+// ```
+pub(crate) fn remove_dbg(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let macro_call = ctx.find_node_at_offset::<ast::MacroCall>()?;
+    let new_contents = adjusted_macro_contents(&macro_call)?;
+
+    let macro_text_range = macro_call.syntax().text_range();
+    let macro_end = if macro_call.semicolon_token().is_some() {
+        macro_text_range.end() - TextSize::of(';')
+    } else {
+        macro_text_range.end()
+    };
+
+    acc.add(
+        AssistId("remove_dbg", AssistKind::Refactor),
+        "Remove dbg!()",
+        macro_text_range,
+        |builder| {
+            builder.replace(TextRange::new(macro_text_range.start(), macro_end), new_contents);
+        },
+    )
+}
+
+fn adjusted_macro_contents(macro_call: &ast::MacroCall) -> Option<String> {
+    let contents = get_valid_macrocall_contents(&macro_call, "dbg")?;
+    let macro_text_with_brackets = macro_call.token_tree()?.syntax().text();
+    let macro_text_in_brackets = macro_text_with_brackets.slice(TextRange::new(
+        TextSize::of('('),
+        macro_text_with_brackets.len() - TextSize::of(')'),
+    ));
+
+    Some(
+        if !is_leaf_or_control_flow_expr(macro_call)
+            && needs_parentheses_around_macro_contents(contents)
+        {
+            format!("({})", macro_text_in_brackets)
+        } else {
+            macro_text_in_brackets.to_string()
+        },
+    )
+}
+
+fn is_leaf_or_control_flow_expr(macro_call: &ast::MacroCall) -> bool {
+    macro_call.syntax().next_sibling().is_none()
+        || match macro_call.syntax().parent() {
+            Some(parent) => match_ast! {
+                match parent {
+                    ast::Condition(_it) => true,
+                    ast::MatchExpr(_it) => true,
+                    _ => false,
+                }
+            },
+            None => false,
+        }
+}
+
+/// Verifies that the given macro_call actually matches the given name
+/// and contains proper ending tokens, then returns the contents between the ending tokens
+fn get_valid_macrocall_contents(
+    macro_call: &ast::MacroCall,
+    macro_name: &str,
+) -> Option<Vec<SyntaxElement>> {
+    let path = macro_call.path()?;
+    let name_ref = path.segment()?.name_ref()?;
+
+    // Make sure it is actually a dbg-macro call, dbg followed by !
+    let excl = path.syntax().next_sibling_or_token()?;
+    if name_ref.text() != macro_name || excl.kind() != T![!] {
+        return None;
+    }
+
+    let mut children_with_tokens = macro_call.token_tree()?.syntax().children_with_tokens();
+    let first_child = children_with_tokens.next()?;
+    let mut contents_between_brackets = children_with_tokens.collect::<Vec<_>>();
+    let last_child = contents_between_brackets.pop()?;
+
+    if contents_between_brackets.is_empty() {
+        None
+    } else {
+        match (first_child.kind(), last_child.kind()) {
+            (T!['('], T![')']) | (T!['['], T![']']) | (T!['{'], T!['}']) => {
+                Some(contents_between_brackets)
+            }
+            _ => None,
+        }
+    }
+}
+
+fn needs_parentheses_around_macro_contents(macro_contents: Vec<SyntaxElement>) -> bool {
+    if macro_contents.len() < 2 {
+        return false;
+    }
+    let mut macro_contents = macro_contents.into_iter().peekable();
+    let mut unpaired_brackets_in_contents = Vec::new();
+    while let Some(element) = macro_contents.next() {
+        match element.kind() {
+            T!['('] | T!['['] | T!['{'] => unpaired_brackets_in_contents.push(element),
+            T![')'] => {
+                if !matches!(unpaired_brackets_in_contents.pop(), Some(correct_bracket) if correct_bracket.kind() == T!['('])
+                {
+                    return true;
+                }
+            }
+            T![']'] => {
+                if !matches!(unpaired_brackets_in_contents.pop(), Some(correct_bracket) if correct_bracket.kind() == T!['['])
+                {
+                    return true;
+                }
+            }
+            T!['}'] => {
+                if !matches!(unpaired_brackets_in_contents.pop(), Some(correct_bracket) if correct_bracket.kind() == T!['{'])
+                {
+                    return true;
+                }
+            }
+            symbol_kind => {
+                let symbol_not_in_bracket = unpaired_brackets_in_contents.is_empty();
+                if symbol_not_in_bracket
+                    && symbol_kind != T![:] // paths
+                    && (symbol_kind != T![.] // field/method access
+                        || macro_contents // range expressions consist of two SyntaxKind::Dot in macro invocations
+                            .peek()
+                            .map(|element| element.kind() == T![.])
+                            .unwrap_or(false))
+                    && symbol_kind != T![?] // try operator
+                    && (symbol_kind.is_punct() || symbol_kind == T![as])
+                {
+                    return true;
+                }
+            }
+        }
+    }
+    !unpaired_brackets_in_contents.is_empty()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn test_remove_dbg() {
+        check_assist(remove_dbg, "$0dbg!(1 + 1)", "1 + 1");
+
+        check_assist(remove_dbg, "dbg!$0((1 + 1))", "(1 + 1)");
+
+        check_assist(remove_dbg, "dbg!(1 $0+ 1)", "1 + 1");
+
+        check_assist(remove_dbg, "let _ = $0dbg!(1 + 1)", "let _ = 1 + 1");
+
+        check_assist(
+            remove_dbg,
+            "
+fn foo(n: usize) {
+    if let Some(_) = dbg!(n.$0checked_sub(4)) {
+        // ...
+    }
+}
+",
+            "
+fn foo(n: usize) {
+    if let Some(_) = n.checked_sub(4) {
+        // ...
+    }
+}
+",
+        );
+
+        check_assist(remove_dbg, "$0dbg!(Foo::foo_test()).bar()", "Foo::foo_test().bar()");
+    }
+
+    #[test]
+    fn test_remove_dbg_with_brackets_and_braces() {
+        check_assist(remove_dbg, "dbg![$01 + 1]", "1 + 1");
+        check_assist(remove_dbg, "dbg!{$01 + 1}", "1 + 1");
+    }
+
+    #[test]
+    fn test_remove_dbg_not_applicable() {
+        check_assist_not_applicable(remove_dbg, "$0vec![1, 2, 3]");
+        check_assist_not_applicable(remove_dbg, "$0dbg(5, 6, 7)");
+        check_assist_not_applicable(remove_dbg, "$0dbg!(5, 6, 7");
+    }
+
+    #[test]
+    fn test_remove_dbg_target() {
+        check_assist_target(
+            remove_dbg,
+            "
+fn foo(n: usize) {
+    if let Some(_) = dbg!(n.$0checked_sub(4)) {
+        // ...
+    }
+}
+",
+            "dbg!(n.checked_sub(4))",
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_keep_semicolon() {
+        // https://github.com/rust-analyzer/rust-analyzer/issues/5129#issuecomment-651399779
+        // not quite though
+        // adding a comment at the end of the line makes
+        // the ast::MacroCall to include the semicolon at the end
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(1 * 20); // needless comment"#,
+            r#"let res = 1 * 20; // needless comment"#,
+        );
+    }
+
+    #[test]
+    fn remove_dbg_from_non_leaf_simple_expression() {
+        check_assist(
+            remove_dbg,
+            "
+fn main() {
+    let mut a = 1;
+    while dbg!$0(a) < 10000 {
+        a += 1;
+    }
+}
+",
+            "
+fn main() {
+    let mut a = 1;
+    while a < 10000 {
+        a += 1;
+    }
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_keep_expression() {
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(a + b).foo();"#,
+            r#"let res = (a + b).foo();"#,
+        );
+
+        check_assist(remove_dbg, r#"let res = $0dbg!(2 + 2) * 5"#, r#"let res = (2 + 2) * 5"#);
+        check_assist(remove_dbg, r#"let res = $0dbg![2 + 2] * 5"#, r#"let res = (2 + 2) * 5"#);
+    }
+
+    #[test]
+    fn test_remove_dbg_method_chaining() {
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(foo().bar()).baz();"#,
+            r#"let res = foo().bar().baz();"#,
+        );
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(foo.bar()).baz();"#,
+            r#"let res = foo.bar().baz();"#,
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_field_chaining() {
+        check_assist(remove_dbg, r#"let res = $0dbg!(foo.bar).baz;"#, r#"let res = foo.bar.baz;"#);
+    }
+
+    #[test]
+    fn test_remove_dbg_from_inside_fn() {
+        check_assist_target(
+            remove_dbg,
+            r#"
+fn square(x: u32) -> u32 {
+    x * x
+}
+
+fn main() {
+    let x = square(dbg$0!(5 + 10));
+    println!("{}", x);
+}"#,
+            "dbg!(5 + 10)",
+        );
+
+        check_assist(
+            remove_dbg,
+            r#"
+fn square(x: u32) -> u32 {
+    x * x
+}
+
+fn main() {
+    let x = square(dbg$0!(5 + 10));
+    println!("{}", x);
+}"#,
+            r#"
+fn square(x: u32) -> u32 {
+    x * x
+}
+
+fn main() {
+    let x = square(5 + 10);
+    println!("{}", x);
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_try_expr() {
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(result?).foo();"#,
+            r#"let res = result?.foo();"#,
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_await_expr() {
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(fut.await).foo();"#,
+            r#"let res = fut.await.foo();"#,
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_as_cast() {
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(3 as usize).foo();"#,
+            r#"let res = (3 as usize).foo();"#,
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_index_expr() {
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(array[3]).foo();"#,
+            r#"let res = array[3].foo();"#,
+        );
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(tuple.3).foo();"#,
+            r#"let res = tuple.3.foo();"#,
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_range_expr() {
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(foo..bar).foo();"#,
+            r#"let res = (foo..bar).foo();"#,
+        );
+        check_assist(
+            remove_dbg,
+            r#"let res = $0dbg!(foo..=bar).foo();"#,
+            r#"let res = (foo..=bar).foo();"#,
+        );
+    }
+
+    #[test]
+    fn test_remove_dbg_followed_by_block() {
+        check_assist(
+            remove_dbg,
+            r#"fn foo() {
+    if $0dbg!(x || y) {}
+}"#,
+            r#"fn foo() {
+    if x || y {}
+}"#,
+        );
+        check_assist(
+            remove_dbg,
+            r#"fn foo() {
+    while let foo = $0dbg!(&x) {}
+}"#,
+            r#"fn foo() {
+    while let foo = &x {}
+}"#,
+        );
+        check_assist(
+            remove_dbg,
+            r#"fn foo() {
+    if let foo = $0dbg!(&x) {}
+}"#,
+            r#"fn foo() {
+    if let foo = &x {}
+}"#,
+        );
+        check_assist(
+            remove_dbg,
+            r#"fn foo() {
+    match $0dbg!(&x) {}
+}"#,
+            r#"fn foo() {
+    match &x {}
+}"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/remove_mut.rs b/crates/ide_assists/src/handlers/remove_mut.rs
new file mode 100644
index 000000000..30d36dacd
--- /dev/null
+++ b/crates/ide_assists/src/handlers/remove_mut.rs
@@ -0,0 +1,37 @@
+use syntax::{SyntaxKind, TextRange, T};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: remove_mut
+//
+// Removes the `mut` keyword.
+//
+// ```
+// impl Walrus {
+//     fn feed(&mut$0 self, amount: u32) {}
+// }
+// ```
+// ->
+// ```
+// impl Walrus {
+//     fn feed(&self, amount: u32) {}
+// }
+// ```
+pub(crate) fn remove_mut(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let mut_token = ctx.find_token_syntax_at_offset(T![mut])?;
+    let delete_from = mut_token.text_range().start();
+    let delete_to = match mut_token.next_token() {
+        Some(it) if it.kind() == SyntaxKind::WHITESPACE => it.text_range().end(),
+        _ => mut_token.text_range().end(),
+    };
+
+    let target = mut_token.text_range();
+    acc.add(
+        AssistId("remove_mut", AssistKind::Refactor),
+        "Remove `mut` keyword",
+        target,
+        |builder| {
+            builder.delete(TextRange::new(delete_from, delete_to));
+        },
+    )
+}
diff --git a/crates/ide_assists/src/handlers/remove_unused_param.rs b/crates/ide_assists/src/handlers/remove_unused_param.rs
new file mode 100644
index 000000000..c961680e2
--- /dev/null
+++ b/crates/ide_assists/src/handlers/remove_unused_param.rs
@@ -0,0 +1,288 @@
+use ide_db::{base_db::FileId, defs::Definition, search::FileReference};
+use syntax::{
+    algo::find_node_at_range,
+    ast::{self, ArgListOwner},
+    AstNode, SourceFile, SyntaxKind, SyntaxNode, TextRange, T,
+};
+use test_utils::mark;
+use SyntaxKind::WHITESPACE;
+
+use crate::{
+    assist_context::AssistBuilder, utils::next_prev, AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: remove_unused_param
+//
+// Removes unused function parameter.
+//
+// ```
+// fn frobnicate(x: i32$0) {}
+//
+// fn main() {
+//     frobnicate(92);
+// }
+// ```
+// ->
+// ```
+// fn frobnicate() {}
+//
+// fn main() {
+//     frobnicate();
+// }
+// ```
+pub(crate) fn remove_unused_param(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let param: ast::Param = ctx.find_node_at_offset()?;
+    let ident_pat = match param.pat()? {
+        ast::Pat::IdentPat(it) => it,
+        _ => return None,
+    };
+    let func = param.syntax().ancestors().find_map(ast::Fn::cast)?;
+    let param_position = func.param_list()?.params().position(|it| it == param)?;
+
+    let fn_def = {
+        let func = ctx.sema.to_def(&func)?;
+        Definition::ModuleDef(func.into())
+    };
+
+    let param_def = {
+        let local = ctx.sema.to_def(&ident_pat)?;
+        Definition::Local(local)
+    };
+    if param_def.usages(&ctx.sema).at_least_one() {
+        mark::hit!(keep_used);
+        return None;
+    }
+    acc.add(
+        AssistId("remove_unused_param", AssistKind::Refactor),
+        "Remove unused parameter",
+        param.syntax().text_range(),
+        |builder| {
+            builder.delete(range_to_remove(param.syntax()));
+            for (file_id, references) in fn_def.usages(&ctx.sema).all() {
+                process_usages(ctx, builder, file_id, references, param_position);
+            }
+        },
+    )
+}
+
+fn process_usages(
+    ctx: &AssistContext,
+    builder: &mut AssistBuilder,
+    file_id: FileId,
+    references: Vec<FileReference>,
+    arg_to_remove: usize,
+) {
+    let source_file = ctx.sema.parse(file_id);
+    builder.edit_file(file_id);
+    for usage in references {
+        if let Some(text_range) = process_usage(&source_file, usage, arg_to_remove) {
+            builder.delete(text_range);
+        }
+    }
+}
+
+fn process_usage(
+    source_file: &SourceFile,
+    FileReference { range, .. }: FileReference,
+    arg_to_remove: usize,
+) -> Option<TextRange> {
+    let call_expr: ast::CallExpr = find_node_at_range(source_file.syntax(), range)?;
+    let call_expr_range = call_expr.expr()?.syntax().text_range();
+    if !call_expr_range.contains_range(range) {
+        return None;
+    }
+    let arg = call_expr.arg_list()?.args().nth(arg_to_remove)?;
+    Some(range_to_remove(arg.syntax()))
+}
+
+fn range_to_remove(node: &SyntaxNode) -> TextRange {
+    let up_to_comma = next_prev().find_map(|dir| {
+        node.siblings_with_tokens(dir)
+            .filter_map(|it| it.into_token())
+            .find(|it| it.kind() == T![,])
+            .map(|it| (dir, it))
+    });
+    if let Some((dir, token)) = up_to_comma {
+        if node.next_sibling().is_some() {
+            let up_to_space = token
+                .siblings_with_tokens(dir)
+                .skip(1)
+                .take_while(|it| it.kind() == WHITESPACE)
+                .last()
+                .and_then(|it| it.into_token());
+            return node
+                .text_range()
+                .cover(up_to_space.map_or(token.text_range(), |it| it.text_range()));
+        }
+        node.text_range().cover(token.text_range())
+    } else {
+        node.text_range()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn remove_unused() {
+        check_assist(
+            remove_unused_param,
+            r#"
+fn a() { foo(9, 2) }
+fn foo(x: i32, $0y: i32) { x; }
+fn b() { foo(9, 2,) }
+"#,
+            r#"
+fn a() { foo(9) }
+fn foo(x: i32) { x; }
+fn b() { foo(9, ) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_unused_first_param() {
+        check_assist(
+            remove_unused_param,
+            r#"
+fn foo($0x: i32, y: i32) { y; }
+fn a() { foo(1, 2) }
+fn b() { foo(1, 2,) }
+"#,
+            r#"
+fn foo(y: i32) { y; }
+fn a() { foo(2) }
+fn b() { foo(2,) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_unused_single_param() {
+        check_assist(
+            remove_unused_param,
+            r#"
+fn foo($0x: i32) { 0; }
+fn a() { foo(1) }
+fn b() { foo(1, ) }
+"#,
+            r#"
+fn foo() { 0; }
+fn a() { foo() }
+fn b() { foo( ) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_unused_surrounded_by_parms() {
+        check_assist(
+            remove_unused_param,
+            r#"
+fn foo(x: i32, $0y: i32, z: i32) { x; }
+fn a() { foo(1, 2, 3) }
+fn b() { foo(1, 2, 3,) }
+"#,
+            r#"
+fn foo(x: i32, z: i32) { x; }
+fn a() { foo(1, 3) }
+fn b() { foo(1, 3,) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_unused_qualified_call() {
+        check_assist(
+            remove_unused_param,
+            r#"
+mod bar { pub fn foo(x: i32, $0y: i32) { x; } }
+fn b() { bar::foo(9, 2) }
+"#,
+            r#"
+mod bar { pub fn foo(x: i32) { x; } }
+fn b() { bar::foo(9) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_unused_turbofished_func() {
+        check_assist(
+            remove_unused_param,
+            r#"
+pub fn foo<T>(x: T, $0y: i32) { x; }
+fn b() { foo::<i32>(9, 2) }
+"#,
+            r#"
+pub fn foo<T>(x: T) { x; }
+fn b() { foo::<i32>(9) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_unused_generic_unused_param_func() {
+        check_assist(
+            remove_unused_param,
+            r#"
+pub fn foo<T>(x: i32, $0y: T) { x; }
+fn b() { foo::<i32>(9, 2) }
+fn b2() { foo(9, 2) }
+"#,
+            r#"
+pub fn foo<T>(x: i32) { x; }
+fn b() { foo::<i32>(9) }
+fn b2() { foo(9) }
+"#,
+        );
+    }
+
+    #[test]
+    fn keep_used() {
+        mark::check!(keep_used);
+        check_assist_not_applicable(
+            remove_unused_param,
+            r#"
+fn foo(x: i32, $0y: i32) { y; }
+fn main() { foo(9, 2) }
+"#,
+        );
+    }
+
+    #[test]
+    fn remove_across_files() {
+        check_assist(
+            remove_unused_param,
+            r#"
+//- /main.rs
+fn foo(x: i32, $0y: i32) { x; }
+
+mod foo;
+
+//- /foo.rs
+use super::foo;
+
+fn bar() {
+    let _ = foo(1, 2);
+}
+"#,
+            r#"
+//- /main.rs
+fn foo(x: i32) { x; }
+
+mod foo;
+
+//- /foo.rs
+use super::foo;
+
+fn bar() {
+    let _ = foo(1);
+}
+"#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/reorder_fields.rs b/crates/ide_assists/src/handlers/reorder_fields.rs
new file mode 100644
index 000000000..fba7d6ddb
--- /dev/null
+++ b/crates/ide_assists/src/handlers/reorder_fields.rs
@@ -0,0 +1,227 @@
+use itertools::Itertools;
+use rustc_hash::FxHashMap;
+
+use hir::{Adt, ModuleDef, PathResolution, Semantics, Struct};
+use ide_db::RootDatabase;
+use syntax::{algo, ast, match_ast, AstNode, SyntaxKind, SyntaxKind::*, SyntaxNode};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: reorder_fields
+//
+// Reorder the fields of record literals and record patterns in the same order as in
+// the definition.
+//
+// ```
+// struct Foo {foo: i32, bar: i32};
+// const test: Foo = $0Foo {bar: 0, foo: 1}
+// ```
+// ->
+// ```
+// struct Foo {foo: i32, bar: i32};
+// const test: Foo = Foo {foo: 1, bar: 0}
+// ```
+//
+pub(crate) fn reorder_fields(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    reorder::<ast::RecordExpr>(acc, ctx).or_else(|| reorder::<ast::RecordPat>(acc, ctx))
+}
+
+fn reorder<R: AstNode>(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let record = ctx.find_node_at_offset::<R>()?;
+    let path = record.syntax().children().find_map(ast::Path::cast)?;
+
+    let ranks = compute_fields_ranks(&path, &ctx)?;
+
+    let fields = get_fields(&record.syntax());
+    let sorted_fields = sorted_by_rank(&fields, |node| {
+        *ranks.get(&get_field_name(node)).unwrap_or(&usize::max_value())
+    });
+
+    if sorted_fields == fields {
+        mark::hit!(reorder_sorted_fields);
+        return None;
+    }
+
+    let target = record.syntax().text_range();
+    acc.add(
+        AssistId("reorder_fields", AssistKind::RefactorRewrite),
+        "Reorder record fields",
+        target,
+        |edit| {
+            let mut rewriter = algo::SyntaxRewriter::default();
+            for (old, new) in fields.iter().zip(&sorted_fields) {
+                rewriter.replace(old, new);
+            }
+            edit.rewrite(rewriter);
+        },
+    )
+}
+
+fn get_fields_kind(node: &SyntaxNode) -> Vec<SyntaxKind> {
+    match node.kind() {
+        RECORD_EXPR => vec![RECORD_EXPR_FIELD],
+        RECORD_PAT => vec![RECORD_PAT_FIELD, IDENT_PAT],
+        _ => vec![],
+    }
+}
+
+fn get_field_name(node: &SyntaxNode) -> String {
+    let res = match_ast! {
+        match node {
+            ast::RecordExprField(field) => field.field_name().map(|it| it.to_string()),
+            ast::RecordPatField(field) => field.field_name().map(|it| it.to_string()),
+            _ => None,
+        }
+    };
+    res.unwrap_or_default()
+}
+
+fn get_fields(record: &SyntaxNode) -> Vec<SyntaxNode> {
+    let kinds = get_fields_kind(record);
+    record.children().flat_map(|n| n.children()).filter(|n| kinds.contains(&n.kind())).collect()
+}
+
+fn sorted_by_rank(
+    fields: &[SyntaxNode],
+    get_rank: impl Fn(&SyntaxNode) -> usize,
+) -> Vec<SyntaxNode> {
+    fields.iter().cloned().sorted_by_key(get_rank).collect()
+}
+
+fn struct_definition(path: &ast::Path, sema: &Semantics<RootDatabase>) -> Option<Struct> {
+    match sema.resolve_path(path) {
+        Some(PathResolution::Def(ModuleDef::Adt(Adt::Struct(s)))) => Some(s),
+        _ => None,
+    }
+}
+
+fn compute_fields_ranks(path: &ast::Path, ctx: &AssistContext) -> Option<FxHashMap<String, usize>> {
+    Some(
+        struct_definition(path, &ctx.sema)?
+            .fields(ctx.db())
+            .iter()
+            .enumerate()
+            .map(|(idx, field)| (field.name(ctx.db()).to_string(), idx))
+            .collect(),
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn reorder_sorted_fields() {
+        mark::check!(reorder_sorted_fields);
+        check_assist_not_applicable(
+            reorder_fields,
+            r#"
+struct Foo {
+    foo: i32,
+    bar: i32,
+}
+
+const test: Foo = $0Foo { foo: 0, bar: 0 };
+"#,
+        )
+    }
+
+    #[test]
+    fn trivial_empty_fields() {
+        check_assist_not_applicable(
+            reorder_fields,
+            r#"
+struct Foo {};
+const test: Foo = $0Foo {}
+"#,
+        )
+    }
+
+    #[test]
+    fn reorder_struct_fields() {
+        check_assist(
+            reorder_fields,
+            r#"
+struct Foo {foo: i32, bar: i32};
+const test: Foo = $0Foo {bar: 0, foo: 1}
+"#,
+            r#"
+struct Foo {foo: i32, bar: i32};
+const test: Foo = Foo {foo: 1, bar: 0}
+"#,
+        )
+    }
+
+    #[test]
+    fn reorder_struct_pattern() {
+        check_assist(
+            reorder_fields,
+            r#"
+struct Foo { foo: i64, bar: i64, baz: i64 }
+
+fn f(f: Foo) -> {
+    match f {
+        $0Foo { baz: 0, ref mut bar, .. } => (),
+        _ => ()
+    }
+}
+"#,
+            r#"
+struct Foo { foo: i64, bar: i64, baz: i64 }
+
+fn f(f: Foo) -> {
+    match f {
+        Foo { ref mut bar, baz: 0, .. } => (),
+        _ => ()
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn reorder_with_extra_field() {
+        check_assist(
+            reorder_fields,
+            r#"
+struct Foo {
+    foo: String,
+    bar: String,
+}
+
+impl Foo {
+    fn new() -> Foo {
+        let foo = String::new();
+        $0Foo {
+            bar: foo.clone(),
+            extra: "Extra field",
+            foo,
+        }
+    }
+}
+"#,
+            r#"
+struct Foo {
+    foo: String,
+    bar: String,
+}
+
+impl Foo {
+    fn new() -> Foo {
+        let foo = String::new();
+        Foo {
+            foo,
+            bar: foo.clone(),
+            extra: "Extra field",
+        }
+    }
+}
+"#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/reorder_impl.rs b/crates/ide_assists/src/handlers/reorder_impl.rs
new file mode 100644
index 000000000..309f291c8
--- /dev/null
+++ b/crates/ide_assists/src/handlers/reorder_impl.rs
@@ -0,0 +1,201 @@
+use itertools::Itertools;
+use rustc_hash::FxHashMap;
+
+use hir::{PathResolution, Semantics};
+use ide_db::RootDatabase;
+use syntax::{
+    algo,
+    ast::{self, NameOwner},
+    AstNode,
+};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: reorder_impl
+//
+// Reorder the methods of an `impl Trait`. The methods will be ordered
+// in the same order as in the trait definition.
+//
+// ```
+// trait Foo {
+//     fn a() {}
+//     fn b() {}
+//     fn c() {}
+// }
+//
+// struct Bar;
+// $0impl Foo for Bar {
+//     fn b() {}
+//     fn c() {}
+//     fn a() {}
+// }
+// ```
+// ->
+// ```
+// trait Foo {
+//     fn a() {}
+//     fn b() {}
+//     fn c() {}
+// }
+//
+// struct Bar;
+// impl Foo for Bar {
+//     fn a() {}
+//     fn b() {}
+//     fn c() {}
+// }
+// ```
+//
+pub(crate) fn reorder_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let impl_ast = ctx.find_node_at_offset::<ast::Impl>()?;
+    let items = impl_ast.assoc_item_list()?;
+    let methods = get_methods(&items);
+
+    let path = impl_ast
+        .trait_()
+        .and_then(|t| match t {
+            ast::Type::PathType(path) => Some(path),
+            _ => None,
+        })?
+        .path()?;
+
+    let ranks = compute_method_ranks(&path, ctx)?;
+    let sorted: Vec<_> = methods
+        .iter()
+        .cloned()
+        .sorted_by_key(|f| {
+            f.name().and_then(|n| ranks.get(&n.to_string()).copied()).unwrap_or(usize::max_value())
+        })
+        .collect();
+
+    // Don't edit already sorted methods:
+    if methods == sorted {
+        mark::hit!(not_applicable_if_sorted);
+        return None;
+    }
+
+    let target = items.syntax().text_range();
+    acc.add(AssistId("reorder_impl", AssistKind::RefactorRewrite), "Sort methods", target, |edit| {
+        let mut rewriter = algo::SyntaxRewriter::default();
+        for (old, new) in methods.iter().zip(&sorted) {
+            rewriter.replace(old.syntax(), new.syntax());
+        }
+        edit.rewrite(rewriter);
+    })
+}
+
+fn compute_method_ranks(path: &ast::Path, ctx: &AssistContext) -> Option<FxHashMap<String, usize>> {
+    let td = trait_definition(path, &ctx.sema)?;
+
+    Some(
+        td.items(ctx.db())
+            .iter()
+            .flat_map(|i| match i {
+                hir::AssocItem::Function(f) => Some(f),
+                _ => None,
+            })
+            .enumerate()
+            .map(|(idx, func)| ((func.name(ctx.db()).to_string(), idx)))
+            .collect(),
+    )
+}
+
+fn trait_definition(path: &ast::Path, sema: &Semantics<RootDatabase>) -> Option<hir::Trait> {
+    match sema.resolve_path(path)? {
+        PathResolution::Def(hir::ModuleDef::Trait(trait_)) => Some(trait_),
+        _ => None,
+    }
+}
+
+fn get_methods(items: &ast::AssocItemList) -> Vec<ast::Fn> {
+    items
+        .assoc_items()
+        .flat_map(|i| match i {
+            ast::AssocItem::Fn(f) => Some(f),
+            _ => None,
+        })
+        .filter(|f| f.name().is_some())
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::mark;
+
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn not_applicable_if_sorted() {
+        mark::check!(not_applicable_if_sorted);
+        check_assist_not_applicable(
+            reorder_impl,
+            r#"
+trait Bar {
+    fn a() {}
+    fn z() {}
+    fn b() {}
+}
+struct Foo;
+$0impl Bar for Foo {
+    fn a() {}
+    fn z() {}
+    fn b() {}
+}
+        "#,
+        )
+    }
+
+    #[test]
+    fn not_applicable_if_empty() {
+        check_assist_not_applicable(
+            reorder_impl,
+            r#"
+trait Bar {};
+struct Foo;
+$0impl Bar for Foo {}
+        "#,
+        )
+    }
+
+    #[test]
+    fn reorder_impl_trait_methods() {
+        check_assist(
+            reorder_impl,
+            r#"
+trait Bar {
+    fn a() {}
+    fn c() {}
+    fn b() {}
+    fn d() {}
+}
+
+struct Foo;
+$0impl Bar for Foo {
+    fn d() {}
+    fn b() {}
+    fn c() {}
+    fn a() {}
+}
+        "#,
+            r#"
+trait Bar {
+    fn a() {}
+    fn c() {}
+    fn b() {}
+    fn d() {}
+}
+
+struct Foo;
+impl Bar for Foo {
+    fn a() {}
+    fn c() {}
+    fn b() {}
+    fn d() {}
+}
+        "#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs b/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
new file mode 100644
index 000000000..c69bc5cac
--- /dev/null
+++ b/crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs
@@ -0,0 +1,404 @@
+use ide_db::helpers::mod_path_to_ast;
+use ide_db::imports_locator;
+use itertools::Itertools;
+use syntax::{
+    ast::{self, make, AstNode, NameOwner},
+    SyntaxKind::{IDENT, WHITESPACE},
+    TextSize,
+};
+
+use crate::{
+    assist_context::{AssistBuilder, AssistContext, Assists},
+    utils::{
+        add_trait_assoc_items_to_impl, filter_assoc_items, generate_trait_impl_text,
+        render_snippet, Cursor, DefaultMethods,
+    },
+    AssistId, AssistKind,
+};
+
+// Assist: replace_derive_with_manual_impl
+//
+// Converts a `derive` impl into a manual one.
+//
+// ```
+// # trait Debug { fn fmt(&self, f: &mut Formatter) -> Result<()>; }
+// #[derive(Deb$0ug, Display)]
+// struct S;
+// ```
+// ->
+// ```
+// # trait Debug { fn fmt(&self, f: &mut Formatter) -> Result<()>; }
+// #[derive(Display)]
+// struct S;
+//
+// impl Debug for S {
+//     fn fmt(&self, f: &mut Formatter) -> Result<()> {
+//         ${0:todo!()}
+//     }
+// }
+// ```
+pub(crate) fn replace_derive_with_manual_impl(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+) -> Option<()> {
+    let attr = ctx.find_node_at_offset::<ast::Attr>()?;
+
+    let has_derive = attr
+        .syntax()
+        .descendants_with_tokens()
+        .filter(|t| t.kind() == IDENT)
+        .find_map(syntax::NodeOrToken::into_token)
+        .filter(|t| t.text() == "derive")
+        .is_some();
+    if !has_derive {
+        return None;
+    }
+
+    let trait_token = ctx.token_at_offset().find(|t| t.kind() == IDENT && t.text() != "derive")?;
+    let trait_path = make::path_unqualified(make::path_segment(make::name_ref(trait_token.text())));
+
+    let adt = attr.syntax().parent().and_then(ast::Adt::cast)?;
+    let annotated_name = adt.name()?;
+    let insert_pos = adt.syntax().text_range().end();
+
+    let current_module = ctx.sema.scope(annotated_name.syntax()).module()?;
+    let current_crate = current_module.krate();
+
+    let found_traits = imports_locator::find_exact_imports(
+        &ctx.sema,
+        current_crate,
+        trait_token.text().to_string(),
+    )
+    .filter_map(|candidate: either::Either<hir::ModuleDef, hir::MacroDef>| match candidate {
+        either::Either::Left(hir::ModuleDef::Trait(trait_)) => Some(trait_),
+        _ => None,
+    })
+    .flat_map(|trait_| {
+        current_module
+            .find_use_path(ctx.sema.db, hir::ModuleDef::Trait(trait_))
+            .as_ref()
+            .map(mod_path_to_ast)
+            .zip(Some(trait_))
+    });
+
+    let mut no_traits_found = true;
+    for (trait_path, trait_) in found_traits.inspect(|_| no_traits_found = false) {
+        add_assist(acc, ctx, &attr, &trait_path, Some(trait_), &adt, &annotated_name, insert_pos)?;
+    }
+    if no_traits_found {
+        add_assist(acc, ctx, &attr, &trait_path, None, &adt, &annotated_name, insert_pos)?;
+    }
+    Some(())
+}
+
+fn add_assist(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+    attr: &ast::Attr,
+    trait_path: &ast::Path,
+    trait_: Option<hir::Trait>,
+    adt: &ast::Adt,
+    annotated_name: &ast::Name,
+    insert_pos: TextSize,
+) -> Option<()> {
+    let target = attr.syntax().text_range();
+    let input = attr.token_tree()?;
+    let label = format!("Convert to manual  `impl {} for {}`", trait_path, annotated_name);
+    let trait_name = trait_path.segment().and_then(|seg| seg.name_ref())?;
+
+    acc.add(
+        AssistId("replace_derive_with_manual_impl", AssistKind::Refactor),
+        label,
+        target,
+        |builder| {
+            let impl_def_with_items =
+                impl_def_from_trait(&ctx.sema, annotated_name, trait_, trait_path);
+            update_attribute(builder, &input, &trait_name, &attr);
+            let trait_path = format!("{}", trait_path);
+            match (ctx.config.snippet_cap, impl_def_with_items) {
+                (None, _) => {
+                    builder.insert(insert_pos, generate_trait_impl_text(adt, &trait_path, ""))
+                }
+                (Some(cap), None) => builder.insert_snippet(
+                    cap,
+                    insert_pos,
+                    generate_trait_impl_text(adt, &trait_path, "    $0"),
+                ),
+                (Some(cap), Some((impl_def, first_assoc_item))) => {
+                    let mut cursor = Cursor::Before(first_assoc_item.syntax());
+                    let placeholder;
+                    if let ast::AssocItem::Fn(ref func) = first_assoc_item {
+                        if let Some(m) = func.syntax().descendants().find_map(ast::MacroCall::cast)
+                        {
+                            if m.syntax().text() == "todo!()" {
+                                placeholder = m;
+                                cursor = Cursor::Replace(placeholder.syntax());
+                            }
+                        }
+                    }
+
+                    builder.insert_snippet(
+                        cap,
+                        insert_pos,
+                        format!("\n\n{}", render_snippet(cap, impl_def.syntax(), cursor)),
+                    )
+                }
+            };
+        },
+    )
+}
+
+fn impl_def_from_trait(
+    sema: &hir::Semantics<ide_db::RootDatabase>,
+    annotated_name: &ast::Name,
+    trait_: Option<hir::Trait>,
+    trait_path: &ast::Path,
+) -> Option<(ast::Impl, ast::AssocItem)> {
+    let trait_ = trait_?;
+    let target_scope = sema.scope(annotated_name.syntax());
+    let trait_items = filter_assoc_items(sema.db, &trait_.items(sema.db), DefaultMethods::No);
+    if trait_items.is_empty() {
+        return None;
+    }
+    let impl_def = make::impl_trait(
+        trait_path.clone(),
+        make::path_unqualified(make::path_segment(make::name_ref(annotated_name.text()))),
+    );
+    let (impl_def, first_assoc_item) =
+        add_trait_assoc_items_to_impl(sema, trait_items, trait_, impl_def, target_scope);
+    Some((impl_def, first_assoc_item))
+}
+
+fn update_attribute(
+    builder: &mut AssistBuilder,
+    input: &ast::TokenTree,
+    trait_name: &ast::NameRef,
+    attr: &ast::Attr,
+) {
+    let new_attr_input = input
+        .syntax()
+        .descendants_with_tokens()
+        .filter(|t| t.kind() == IDENT)
+        .filter_map(|t| t.into_token().map(|t| t.text().to_string()))
+        .filter(|t| t != trait_name.text())
+        .collect::<Vec<_>>();
+    let has_more_derives = !new_attr_input.is_empty();
+
+    if has_more_derives {
+        let new_attr_input = format!("({})", new_attr_input.iter().format(", "));
+        builder.replace(input.syntax().text_range(), new_attr_input);
+    } else {
+        let attr_range = attr.syntax().text_range();
+        builder.delete(attr_range);
+
+        if let Some(line_break_range) = attr
+            .syntax()
+            .next_sibling_or_token()
+            .filter(|t| t.kind() == WHITESPACE)
+            .map(|t| t.text_range())
+        {
+            builder.delete(line_break_range);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn add_custom_impl_debug() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            "
+mod fmt {
+    pub struct Error;
+    pub type Result = Result<(), Error>;
+    pub struct Formatter<'a>;
+    pub trait Debug {
+        fn fmt(&self, f: &mut Formatter<'_>) -> Result;
+    }
+}
+
+#[derive(Debu$0g)]
+struct Foo {
+    bar: String,
+}
+",
+            "
+mod fmt {
+    pub struct Error;
+    pub type Result = Result<(), Error>;
+    pub struct Formatter<'a>;
+    pub trait Debug {
+        fn fmt(&self, f: &mut Formatter<'_>) -> Result;
+    }
+}
+
+struct Foo {
+    bar: String,
+}
+
+impl fmt::Debug for Foo {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        ${0:todo!()}
+    }
+}
+",
+        )
+    }
+    #[test]
+    fn add_custom_impl_all() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            "
+mod foo {
+    pub trait Bar {
+        type Qux;
+        const Baz: usize = 42;
+        const Fez: usize;
+        fn foo();
+        fn bar() {}
+    }
+}
+
+#[derive($0Bar)]
+struct Foo {
+    bar: String,
+}
+",
+            "
+mod foo {
+    pub trait Bar {
+        type Qux;
+        const Baz: usize = 42;
+        const Fez: usize;
+        fn foo();
+        fn bar() {}
+    }
+}
+
+struct Foo {
+    bar: String,
+}
+
+impl foo::Bar for Foo {
+    $0type Qux;
+
+    const Baz: usize = 42;
+
+    const Fez: usize;
+
+    fn foo() {
+        todo!()
+    }
+}
+",
+        )
+    }
+    #[test]
+    fn add_custom_impl_for_unique_input() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            "
+#[derive(Debu$0g)]
+struct Foo {
+    bar: String,
+}
+            ",
+            "
+struct Foo {
+    bar: String,
+}
+
+impl Debug for Foo {
+    $0
+}
+            ",
+        )
+    }
+
+    #[test]
+    fn add_custom_impl_for_with_visibility_modifier() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            "
+#[derive(Debug$0)]
+pub struct Foo {
+    bar: String,
+}
+            ",
+            "
+pub struct Foo {
+    bar: String,
+}
+
+impl Debug for Foo {
+    $0
+}
+            ",
+        )
+    }
+
+    #[test]
+    fn add_custom_impl_when_multiple_inputs() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            "
+#[derive(Display, Debug$0, Serialize)]
+struct Foo {}
+            ",
+            "
+#[derive(Display, Serialize)]
+struct Foo {}
+
+impl Debug for Foo {
+    $0
+}
+            ",
+        )
+    }
+
+    #[test]
+    fn test_ignore_derive_macro_without_input() {
+        check_assist_not_applicable(
+            replace_derive_with_manual_impl,
+            "
+#[derive($0)]
+struct Foo {}
+            ",
+        )
+    }
+
+    #[test]
+    fn test_ignore_if_cursor_on_param() {
+        check_assist_not_applicable(
+            replace_derive_with_manual_impl,
+            "
+#[derive$0(Debug)]
+struct Foo {}
+            ",
+        );
+
+        check_assist_not_applicable(
+            replace_derive_with_manual_impl,
+            "
+#[derive(Debug)$0]
+struct Foo {}
+            ",
+        )
+    }
+
+    #[test]
+    fn test_ignore_if_not_derive() {
+        check_assist_not_applicable(
+            replace_derive_with_manual_impl,
+            "
+#[allow(non_camel_$0case_types)]
+struct Foo {}
+            ",
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/replace_if_let_with_match.rs b/crates/ide_assists/src/handlers/replace_if_let_with_match.rs
new file mode 100644
index 000000000..aee880625
--- /dev/null
+++ b/crates/ide_assists/src/handlers/replace_if_let_with_match.rs
@@ -0,0 +1,599 @@
+use std::iter;
+
+use ide_db::{ty_filter::TryEnum, RootDatabase};
+use syntax::{
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+        make,
+    },
+    AstNode,
+};
+
+use crate::{
+    utils::{does_pat_match_variant, unwrap_trivial_block},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: replace_if_let_with_match
+//
+// Replaces `if let` with an else branch with a `match` expression.
+//
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     $0if let Action::Move { distance } = action {
+//         foo(distance)
+//     } else {
+//         bar()
+//     }
+// }
+// ```
+// ->
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move { distance } => foo(distance),
+//         _ => bar(),
+//     }
+// }
+// ```
+pub(crate) fn replace_if_let_with_match(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let if_expr: ast::IfExpr = ctx.find_node_at_offset()?;
+    let cond = if_expr.condition()?;
+    let pat = cond.pat()?;
+    let expr = cond.expr()?;
+    let then_block = if_expr.then_branch()?;
+    let else_block = match if_expr.else_branch()? {
+        ast::ElseBranch::Block(it) => it,
+        ast::ElseBranch::IfExpr(_) => return None,
+    };
+
+    let target = if_expr.syntax().text_range();
+    acc.add(
+        AssistId("replace_if_let_with_match", AssistKind::RefactorRewrite),
+        "Replace with match",
+        target,
+        move |edit| {
+            let match_expr = {
+                let then_arm = {
+                    let then_block = then_block.reset_indent().indent(IndentLevel(1));
+                    let then_expr = unwrap_trivial_block(then_block);
+                    make::match_arm(vec![pat.clone()], then_expr)
+                };
+                let else_arm = {
+                    let pattern = ctx
+                        .sema
+                        .type_of_pat(&pat)
+                        .and_then(|ty| TryEnum::from_ty(&ctx.sema, &ty))
+                        .map(|it| {
+                            if does_pat_match_variant(&pat, &it.sad_pattern()) {
+                                it.happy_pattern()
+                            } else {
+                                it.sad_pattern()
+                            }
+                        })
+                        .unwrap_or_else(|| make::wildcard_pat().into());
+                    let else_expr = unwrap_trivial_block(else_block);
+                    make::match_arm(vec![pattern], else_expr)
+                };
+                let match_expr =
+                    make::expr_match(expr, make::match_arm_list(vec![then_arm, else_arm]));
+                match_expr.indent(IndentLevel::from_node(if_expr.syntax()))
+            };
+
+            edit.replace_ast::<ast::Expr>(if_expr.into(), match_expr);
+        },
+    )
+}
+
+// Assist: replace_match_with_if_let
+//
+// Replaces a binary `match` with a wildcard pattern and no guards with an `if let` expression.
+//
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     $0match action {
+//         Action::Move { distance } => foo(distance),
+//         _ => bar(),
+//     }
+// }
+// ```
+// ->
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     if let Action::Move { distance } = action {
+//         foo(distance)
+//     } else {
+//         bar()
+//     }
+// }
+// ```
+pub(crate) fn replace_match_with_if_let(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let match_expr: ast::MatchExpr = ctx.find_node_at_offset()?;
+    let mut arms = match_expr.match_arm_list()?.arms();
+    let first_arm = arms.next()?;
+    let second_arm = arms.next()?;
+    if arms.next().is_some() || first_arm.guard().is_some() || second_arm.guard().is_some() {
+        return None;
+    }
+    let condition_expr = match_expr.expr()?;
+    let (if_let_pat, then_expr, else_expr) = if is_pat_wildcard_or_sad(&ctx.sema, &first_arm.pat()?)
+    {
+        (second_arm.pat()?, second_arm.expr()?, first_arm.expr()?)
+    } else if is_pat_wildcard_or_sad(&ctx.sema, &second_arm.pat()?) {
+        (first_arm.pat()?, first_arm.expr()?, second_arm.expr()?)
+    } else {
+        return None;
+    };
+
+    let target = match_expr.syntax().text_range();
+    acc.add(
+        AssistId("replace_match_with_if_let", AssistKind::RefactorRewrite),
+        "Replace with if let",
+        target,
+        move |edit| {
+            let condition = make::condition(condition_expr, Some(if_let_pat));
+            let then_block = match then_expr.reset_indent() {
+                ast::Expr::BlockExpr(block) => block,
+                expr => make::block_expr(iter::empty(), Some(expr)),
+            };
+            let else_expr = match else_expr {
+                ast::Expr::BlockExpr(block)
+                    if block.statements().count() == 0 && block.tail_expr().is_none() =>
+                {
+                    None
+                }
+                ast::Expr::TupleExpr(tuple) if tuple.fields().count() == 0 => None,
+                expr => Some(expr),
+            };
+            let if_let_expr = make::expr_if(
+                condition,
+                then_block,
+                else_expr.map(|else_expr| {
+                    ast::ElseBranch::Block(make::block_expr(iter::empty(), Some(else_expr)))
+                }),
+            )
+            .indent(IndentLevel::from_node(match_expr.syntax()));
+
+            edit.replace_ast::<ast::Expr>(match_expr.into(), if_let_expr);
+        },
+    )
+}
+
+fn is_pat_wildcard_or_sad(sema: &hir::Semantics<RootDatabase>, pat: &ast::Pat) -> bool {
+    sema.type_of_pat(&pat)
+        .and_then(|ty| TryEnum::from_ty(sema, &ty))
+        .map(|it| it.sad_pattern().syntax().text() == pat.syntax().text())
+        .unwrap_or_else(|| matches!(pat, ast::Pat::WildcardPat(_)))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::{check_assist, check_assist_target};
+
+    #[test]
+    fn test_replace_if_let_with_match_unwraps_simple_expressions() {
+        check_assist(
+            replace_if_let_with_match,
+            r#"
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        if $0let VariantData::Struct(..) = *self {
+            true
+        } else {
+            false
+        }
+    }
+}           "#,
+            r#"
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        match *self {
+            VariantData::Struct(..) => true,
+            _ => false,
+        }
+    }
+}           "#,
+        )
+    }
+
+    #[test]
+    fn test_replace_if_let_with_match_doesnt_unwrap_multiline_expressions() {
+        check_assist(
+            replace_if_let_with_match,
+            r#"
+fn foo() {
+    if $0let VariantData::Struct(..) = a {
+        bar(
+            123
+        )
+    } else {
+        false
+    }
+}           "#,
+            r#"
+fn foo() {
+    match a {
+        VariantData::Struct(..) => {
+            bar(
+                123
+            )
+        }
+        _ => false,
+    }
+}           "#,
+        )
+    }
+
+    #[test]
+    fn replace_if_let_with_match_target() {
+        check_assist_target(
+            replace_if_let_with_match,
+            r#"
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        if $0let VariantData::Struct(..) = *self {
+            true
+        } else {
+            false
+        }
+    }
+}           "#,
+            "if let VariantData::Struct(..) = *self {
+            true
+        } else {
+            false
+        }",
+        );
+    }
+
+    #[test]
+    fn special_case_option() {
+        check_assist(
+            replace_if_let_with_match,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn foo(x: Option<i32>) {
+    $0if let Some(x) = x {
+        println!("{}", x)
+    } else {
+        println!("none")
+    }
+}
+           "#,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn foo(x: Option<i32>) {
+    match x {
+        Some(x) => println!("{}", x),
+        None => println!("none"),
+    }
+}
+           "#,
+        );
+    }
+
+    #[test]
+    fn special_case_inverted_option() {
+        check_assist(
+            replace_if_let_with_match,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn foo(x: Option<i32>) {
+    $0if let None = x {
+        println!("none")
+    } else {
+        println!("some")
+    }
+}
+           "#,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn foo(x: Option<i32>) {
+    match x {
+        None => println!("none"),
+        Some(_) => println!("some"),
+    }
+}
+           "#,
+        );
+    }
+
+    #[test]
+    fn special_case_result() {
+        check_assist(
+            replace_if_let_with_match,
+            r#"
+enum Result<T, E> { Ok(T), Err(E) }
+use Result::*;
+
+fn foo(x: Result<i32, ()>) {
+    $0if let Ok(x) = x {
+        println!("{}", x)
+    } else {
+        println!("none")
+    }
+}
+           "#,
+            r#"
+enum Result<T, E> { Ok(T), Err(E) }
+use Result::*;
+
+fn foo(x: Result<i32, ()>) {
+    match x {
+        Ok(x) => println!("{}", x),
+        Err(_) => println!("none"),
+    }
+}
+           "#,
+        );
+    }
+
+    #[test]
+    fn special_case_inverted_result() {
+        check_assist(
+            replace_if_let_with_match,
+            r#"
+enum Result<T, E> { Ok(T), Err(E) }
+use Result::*;
+
+fn foo(x: Result<i32, ()>) {
+    $0if let Err(x) = x {
+        println!("{}", x)
+    } else {
+        println!("ok")
+    }
+}
+           "#,
+            r#"
+enum Result<T, E> { Ok(T), Err(E) }
+use Result::*;
+
+fn foo(x: Result<i32, ()>) {
+    match x {
+        Err(x) => println!("{}", x),
+        Ok(_) => println!("ok"),
+    }
+}
+           "#,
+        );
+    }
+
+    #[test]
+    fn nested_indent() {
+        check_assist(
+            replace_if_let_with_match,
+            r#"
+fn main() {
+    if true {
+        $0if let Ok(rel_path) = path.strip_prefix(root_path) {
+            let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+            Some((*id, rel_path))
+        } else {
+            None
+        }
+    }
+}
+"#,
+            r#"
+fn main() {
+    if true {
+        match path.strip_prefix(root_path) {
+            Ok(rel_path) => {
+                let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+                Some((*id, rel_path))
+            }
+            _ => None,
+        }
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn test_replace_match_with_if_let_unwraps_simple_expressions() {
+        check_assist(
+            replace_match_with_if_let,
+            r#"
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        $0match *self {
+            VariantData::Struct(..) => true,
+            _ => false,
+        }
+    }
+}           "#,
+            r#"
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        if let VariantData::Struct(..) = *self {
+            true
+        } else {
+            false
+        }
+    }
+}           "#,
+        )
+    }
+
+    #[test]
+    fn test_replace_match_with_if_let_doesnt_unwrap_multiline_expressions() {
+        check_assist(
+            replace_match_with_if_let,
+            r#"
+fn foo() {
+    $0match a {
+        VariantData::Struct(..) => {
+            bar(
+                123
+            )
+        }
+        _ => false,
+    }
+}           "#,
+            r#"
+fn foo() {
+    if let VariantData::Struct(..) = a {
+        bar(
+            123
+        )
+    } else {
+        false
+    }
+}           "#,
+        )
+    }
+
+    #[test]
+    fn replace_match_with_if_let_target() {
+        check_assist_target(
+            replace_match_with_if_let,
+            r#"
+impl VariantData {
+    pub fn is_struct(&self) -> bool {
+        $0match *self {
+            VariantData::Struct(..) => true,
+            _ => false,
+        }
+    }
+}           "#,
+            r#"match *self {
+            VariantData::Struct(..) => true,
+            _ => false,
+        }"#,
+        );
+    }
+
+    #[test]
+    fn special_case_option_match_to_if_let() {
+        check_assist(
+            replace_match_with_if_let,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn foo(x: Option<i32>) {
+    $0match x {
+        Some(x) => println!("{}", x),
+        None => println!("none"),
+    }
+}
+           "#,
+            r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn foo(x: Option<i32>) {
+    if let Some(x) = x {
+        println!("{}", x)
+    } else {
+        println!("none")
+    }
+}
+           "#,
+        );
+    }
+
+    #[test]
+    fn special_case_result_match_to_if_let() {
+        check_assist(
+            replace_match_with_if_let,
+            r#"
+enum Result<T, E> { Ok(T), Err(E) }
+use Result::*;
+
+fn foo(x: Result<i32, ()>) {
+    $0match x {
+        Ok(x) => println!("{}", x),
+        Err(_) => println!("none"),
+    }
+}
+           "#,
+            r#"
+enum Result<T, E> { Ok(T), Err(E) }
+use Result::*;
+
+fn foo(x: Result<i32, ()>) {
+    if let Ok(x) = x {
+        println!("{}", x)
+    } else {
+        println!("none")
+    }
+}
+           "#,
+        );
+    }
+
+    #[test]
+    fn nested_indent_match_to_if_let() {
+        check_assist(
+            replace_match_with_if_let,
+            r#"
+fn main() {
+    if true {
+        $0match path.strip_prefix(root_path) {
+            Ok(rel_path) => {
+                let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+                Some((*id, rel_path))
+            }
+            _ => None,
+        }
+    }
+}
+"#,
+            r#"
+fn main() {
+    if true {
+        if let Ok(rel_path) = path.strip_prefix(root_path) {
+            let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+            Some((*id, rel_path))
+        } else {
+            None
+        }
+    }
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn replace_match_with_if_let_empty_wildcard_expr() {
+        check_assist(
+            replace_match_with_if_let,
+            r#"
+fn main() {
+    $0match path.strip_prefix(root_path) {
+        Ok(rel_path) => println!("{}", rel_path),
+        _ => (),
+    }
+}
+"#,
+            r#"
+fn main() {
+    if let Ok(rel_path) = path.strip_prefix(root_path) {
+        println!("{}", rel_path)
+    }
+}
+"#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/replace_impl_trait_with_generic.rs b/crates/ide_assists/src/handlers/replace_impl_trait_with_generic.rs
new file mode 100644
index 000000000..ff25b61ea
--- /dev/null
+++ b/crates/ide_assists/src/handlers/replace_impl_trait_with_generic.rs
@@ -0,0 +1,168 @@
+use syntax::ast::{self, edit::AstNodeEdit, make, AstNode, GenericParamsOwner};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: replace_impl_trait_with_generic
+//
+// Replaces `impl Trait` function argument with the named generic.
+//
+// ```
+// fn foo(bar: $0impl Bar) {}
+// ```
+// ->
+// ```
+// fn foo<B: Bar>(bar: B) {}
+// ```
+pub(crate) fn replace_impl_trait_with_generic(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+) -> Option<()> {
+    let type_impl_trait = ctx.find_node_at_offset::<ast::ImplTraitType>()?;
+    let type_param = type_impl_trait.syntax().parent().and_then(ast::Param::cast)?;
+    let type_fn = type_param.syntax().ancestors().find_map(ast::Fn::cast)?;
+
+    let impl_trait_ty = type_impl_trait.type_bound_list()?;
+
+    let target = type_fn.syntax().text_range();
+    acc.add(
+        AssistId("replace_impl_trait_with_generic", AssistKind::RefactorRewrite),
+        "Replace impl trait with generic",
+        target,
+        |edit| {
+            let generic_letter = impl_trait_ty.to_string().chars().next().unwrap().to_string();
+
+            let generic_param_list = type_fn
+                .generic_param_list()
+                .unwrap_or_else(|| make::generic_param_list(None))
+                .append_param(make::generic_param(generic_letter.clone(), Some(impl_trait_ty)));
+
+            let new_type_fn = type_fn
+                .replace_descendant::<ast::Type>(type_impl_trait.into(), make::ty(&generic_letter))
+                .with_generic_param_list(generic_param_list);
+
+            edit.replace_ast(type_fn.clone(), new_type_fn);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    use crate::tests::check_assist;
+
+    #[test]
+    fn replace_impl_trait_with_generic_params() {
+        check_assist(
+            replace_impl_trait_with_generic,
+            r#"
+            fn foo<G>(bar: $0impl Bar) {}
+            "#,
+            r#"
+            fn foo<G, B: Bar>(bar: B) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn replace_impl_trait_without_generic_params() {
+        check_assist(
+            replace_impl_trait_with_generic,
+            r#"
+            fn foo(bar: $0impl Bar) {}
+            "#,
+            r#"
+            fn foo<B: Bar>(bar: B) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn replace_two_impl_trait_with_generic_params() {
+        check_assist(
+            replace_impl_trait_with_generic,
+            r#"
+            fn foo<G>(foo: impl Foo, bar: $0impl Bar) {}
+            "#,
+            r#"
+            fn foo<G, B: Bar>(foo: impl Foo, bar: B) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn replace_impl_trait_with_empty_generic_params() {
+        check_assist(
+            replace_impl_trait_with_generic,
+            r#"
+            fn foo<>(bar: $0impl Bar) {}
+            "#,
+            r#"
+            fn foo<B: Bar>(bar: B) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn replace_impl_trait_with_empty_multiline_generic_params() {
+        check_assist(
+            replace_impl_trait_with_generic,
+            r#"
+            fn foo<
+            >(bar: $0impl Bar) {}
+            "#,
+            r#"
+            fn foo<B: Bar
+            >(bar: B) {}
+            "#,
+        );
+    }
+
+    #[test]
+    #[ignore = "This case is very rare but there is no simple solutions to fix it."]
+    fn replace_impl_trait_with_exist_generic_letter() {
+        check_assist(
+            replace_impl_trait_with_generic,
+            r#"
+            fn foo<B>(bar: $0impl Bar) {}
+            "#,
+            r#"
+            fn foo<B, C: Bar>(bar: C) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn replace_impl_trait_with_multiline_generic_params() {
+        check_assist(
+            replace_impl_trait_with_generic,
+            r#"
+            fn foo<
+                G: Foo,
+                F,
+                H,
+            >(bar: $0impl Bar) {}
+            "#,
+            r#"
+            fn foo<
+                G: Foo,
+                F,
+                H, B: Bar
+            >(bar: B) {}
+            "#,
+        );
+    }
+
+    #[test]
+    fn replace_impl_trait_multiple() {
+        check_assist(
+            replace_impl_trait_with_generic,
+            r#"
+            fn foo(bar: $0impl Foo + Bar) {}
+            "#,
+            r#"
+            fn foo<F: Foo + Bar>(bar: F) {}
+            "#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/replace_let_with_if_let.rs b/crates/ide_assists/src/handlers/replace_let_with_if_let.rs
new file mode 100644
index 000000000..5a27ada6b
--- /dev/null
+++ b/crates/ide_assists/src/handlers/replace_let_with_if_let.rs
@@ -0,0 +1,101 @@
+use std::iter::once;
+
+use syntax::{
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+        make,
+    },
+    AstNode, T,
+};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+use ide_db::ty_filter::TryEnum;
+
+// Assist: replace_let_with_if_let
+//
+// Replaces `let` with an `if-let`.
+//
+// ```
+// # enum Option<T> { Some(T), None }
+//
+// fn main(action: Action) {
+//     $0let x = compute();
+// }
+//
+// fn compute() -> Option<i32> { None }
+// ```
+// ->
+// ```
+// # enum Option<T> { Some(T), None }
+//
+// fn main(action: Action) {
+//     if let Some(x) = compute() {
+//     }
+// }
+//
+// fn compute() -> Option<i32> { None }
+// ```
+pub(crate) fn replace_let_with_if_let(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let let_kw = ctx.find_token_syntax_at_offset(T![let])?;
+    let let_stmt = let_kw.ancestors().find_map(ast::LetStmt::cast)?;
+    let init = let_stmt.initializer()?;
+    let original_pat = let_stmt.pat()?;
+    let ty = ctx.sema.type_of_expr(&init)?;
+    let happy_variant = TryEnum::from_ty(&ctx.sema, &ty).map(|it| it.happy_case());
+
+    let target = let_kw.text_range();
+    acc.add(
+        AssistId("replace_let_with_if_let", AssistKind::RefactorRewrite),
+        "Replace with if-let",
+        target,
+        |edit| {
+            let with_placeholder: ast::Pat = match happy_variant {
+                None => make::wildcard_pat().into(),
+                Some(var_name) => make::tuple_struct_pat(
+                    make::path_unqualified(make::path_segment(make::name_ref(var_name))),
+                    once(make::wildcard_pat().into()),
+                )
+                .into(),
+            };
+            let block =
+                make::block_expr(None, None).indent(IndentLevel::from_node(let_stmt.syntax()));
+            let if_ = make::expr_if(make::condition(init, Some(with_placeholder)), block, None);
+            let stmt = make::expr_stmt(if_);
+
+            let placeholder = stmt.syntax().descendants().find_map(ast::WildcardPat::cast).unwrap();
+            let stmt = stmt.replace_descendant(placeholder.into(), original_pat);
+
+            edit.replace_ast(ast::Stmt::from(let_stmt), ast::Stmt::from(stmt));
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::check_assist;
+
+    use super::*;
+
+    #[test]
+    fn replace_let_unknown_enum() {
+        check_assist(
+            replace_let_with_if_let,
+            r"
+enum E<T> { X(T), Y(T) }
+
+fn main() {
+    $0let x = E::X(92);
+}
+            ",
+            r"
+enum E<T> { X(T), Y(T) }
+
+fn main() {
+    if let x = E::X(92) {
+    }
+}
+            ",
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs b/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs
new file mode 100644
index 000000000..f3bc6cf39
--- /dev/null
+++ b/crates/ide_assists/src/handlers/replace_qualified_name_with_use.rs
@@ -0,0 +1,678 @@
+use ide_db::helpers::insert_use::{insert_use, ImportScope};
+use syntax::{algo::SyntaxRewriter, ast, match_ast, AstNode, SyntaxNode};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: replace_qualified_name_with_use
+//
+// Adds a use statement for a given fully-qualified name.
+//
+// ```
+// fn process(map: std::collections::$0HashMap<String, String>) {}
+// ```
+// ->
+// ```
+// use std::collections::HashMap;
+//
+// fn process(map: HashMap<String, String>) {}
+// ```
+pub(crate) fn replace_qualified_name_with_use(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+) -> Option<()> {
+    let path: ast::Path = ctx.find_node_at_offset()?;
+    // We don't want to mess with use statements
+    if path.syntax().ancestors().find_map(ast::Use::cast).is_some() {
+        return None;
+    }
+    if path.qualifier().is_none() {
+        mark::hit!(dont_import_trivial_paths);
+        return None;
+    }
+
+    let target = path.syntax().text_range();
+    let scope = ImportScope::find_insert_use_container(path.syntax(), &ctx.sema)?;
+    let syntax = scope.as_syntax_node();
+    acc.add(
+        AssistId("replace_qualified_name_with_use", AssistKind::RefactorRewrite),
+        "Replace qualified path with use",
+        target,
+        |builder| {
+            // Now that we've brought the name into scope, re-qualify all paths that could be
+            // affected (that is, all paths inside the node we added the `use` to).
+            let mut rewriter = SyntaxRewriter::default();
+            shorten_paths(&mut rewriter, syntax.clone(), &path);
+            if let Some(ref import_scope) = ImportScope::from(syntax.clone()) {
+                rewriter += insert_use(import_scope, path, ctx.config.insert_use.merge);
+                builder.rewrite(rewriter);
+            }
+        },
+    )
+}
+
+/// Adds replacements to `re` that shorten `path` in all descendants of `node`.
+fn shorten_paths(rewriter: &mut SyntaxRewriter<'static>, node: SyntaxNode, path: &ast::Path) {
+    for child in node.children() {
+        match_ast! {
+            match child {
+                // Don't modify `use` items, as this can break the `use` item when injecting a new
+                // import into the use tree.
+                ast::Use(_it) => continue,
+                // Don't descend into submodules, they don't have the same `use` items in scope.
+                ast::Module(_it) => continue,
+
+                ast::Path(p) => {
+                    match maybe_replace_path(rewriter, p.clone(), path.clone()) {
+                        Some(()) => {},
+                        None => shorten_paths(rewriter, p.syntax().clone(), path),
+                    }
+                },
+                _ => shorten_paths(rewriter, child, path),
+            }
+        }
+    }
+}
+
+fn maybe_replace_path(
+    rewriter: &mut SyntaxRewriter<'static>,
+    path: ast::Path,
+    target: ast::Path,
+) -> Option<()> {
+    if !path_eq(path.clone(), target) {
+        return None;
+    }
+
+    // Shorten `path`, leaving only its last segment.
+    if let Some(parent) = path.qualifier() {
+        rewriter.delete(parent.syntax());
+    }
+    if let Some(double_colon) = path.coloncolon_token() {
+        rewriter.delete(&double_colon);
+    }
+
+    Some(())
+}
+
+fn path_eq(lhs: ast::Path, rhs: ast::Path) -> bool {
+    let mut lhs_curr = lhs;
+    let mut rhs_curr = rhs;
+    loop {
+        match (lhs_curr.segment(), rhs_curr.segment()) {
+            (Some(lhs), Some(rhs)) if lhs.syntax().text() == rhs.syntax().text() => (),
+            _ => return false,
+        }
+
+        match (lhs_curr.qualifier(), rhs_curr.qualifier()) {
+            (Some(lhs), Some(rhs)) => {
+                lhs_curr = lhs;
+                rhs_curr = rhs;
+            }
+            (None, None) => return true,
+            _ => return false,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn test_replace_already_imported() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"use std::fs;
+
+fn main() {
+    std::f$0s::Path
+}",
+            r"use std::fs;
+
+fn main() {
+    fs::Path
+}",
+        )
+    }
+
+    #[test]
+    fn test_replace_add_use_no_anchor() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+std::fmt::Debug$0
+    ",
+            r"
+use std::fmt::Debug;
+
+Debug
+    ",
+        );
+    }
+    #[test]
+    fn test_replace_add_use_no_anchor_with_item_below() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+std::fmt::Debug$0
+
+fn main() {
+}
+    ",
+            r"
+use std::fmt::Debug;
+
+Debug
+
+fn main() {
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_add_use_no_anchor_with_item_above() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+fn main() {
+}
+
+std::fmt::Debug$0
+    ",
+            r"
+use std::fmt::Debug;
+
+fn main() {
+}
+
+Debug
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_add_use_no_anchor_2seg() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+std::fmt$0::Debug
+    ",
+            r"
+use std::fmt;
+
+fmt::Debug
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_add_use() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use stdx;
+
+impl std::fmt::Debug$0 for Foo {
+}
+    ",
+            r"
+use std::fmt::Debug;
+
+use stdx;
+
+impl Debug for Foo {
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_file_use_other_anchor() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+impl std::fmt::Debug$0 for Foo {
+}
+    ",
+            r"
+use std::fmt::Debug;
+
+impl Debug for Foo {
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_add_use_other_anchor_indent() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+    impl std::fmt::Debug$0 for Foo {
+    }
+    ",
+            r"
+    use std::fmt::Debug;
+
+    impl Debug for Foo {
+    }
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_split_different() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt;
+
+impl std::io$0 for Foo {
+}
+    ",
+            r"
+use std::{fmt, io};
+
+impl io for Foo {
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_split_self_for_use() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt;
+
+impl std::fmt::Debug$0 for Foo {
+}
+    ",
+            r"
+use std::fmt::{self, Debug};
+
+impl Debug for Foo {
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_split_self_for_target() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt::Debug;
+
+impl std::fmt$0 for Foo {
+}
+    ",
+            r"
+use std::fmt::{self, Debug};
+
+impl fmt for Foo {
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn test_replace_add_to_nested_self_nested() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt::{Debug, nested::{Display}};
+
+impl std::fmt::nested$0 for Foo {
+}
+",
+            r"
+use std::fmt::{Debug, nested::{self, Display}};
+
+impl nested for Foo {
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_replace_add_to_nested_self_already_included() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt::{Debug, nested::{self, Display}};
+
+impl std::fmt::nested$0 for Foo {
+}
+",
+            r"
+use std::fmt::{Debug, nested::{self, Display}};
+
+impl nested for Foo {
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_replace_add_to_nested_nested() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt::{Debug, nested::{Display}};
+
+impl std::fmt::nested::Debug$0 for Foo {
+}
+",
+            r"
+use std::fmt::{Debug, nested::{Debug, Display}};
+
+impl Debug for Foo {
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_replace_split_common_target_longer() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt::Debug;
+
+impl std::fmt::nested::Display$0 for Foo {
+}
+",
+            r"
+use std::fmt::{Debug, nested::Display};
+
+impl Display for Foo {
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_replace_split_common_use_longer() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt::nested::Debug;
+
+impl std::fmt::Display$0 for Foo {
+}
+",
+            r"
+use std::fmt::{Display, nested::Debug};
+
+impl Display for Foo {
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_replace_use_nested_import() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use crate::{
+    ty::{Substs, Ty},
+    AssocItem,
+};
+
+fn foo() { crate::ty::lower$0::trait_env() }
+",
+            r"
+use crate::{AssocItem, ty::{Substs, Ty, lower}};
+
+fn foo() { lower::trait_env() }
+",
+        );
+    }
+
+    #[test]
+    fn test_replace_alias() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt as foo;
+
+impl foo::Debug$0 for Foo {
+}
+",
+            r"
+use std::fmt as foo;
+
+use foo::Debug;
+
+impl Debug for Foo {
+}
+",
+        );
+    }
+
+    #[test]
+    fn dont_import_trivial_paths() {
+        mark::check!(dont_import_trivial_paths);
+        check_assist_not_applicable(
+            replace_qualified_name_with_use,
+            r"
+impl foo$0 for Foo {
+}
+",
+        );
+    }
+
+    #[test]
+    fn test_replace_not_applicable_in_use() {
+        check_assist_not_applicable(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt$0;
+",
+        );
+    }
+
+    #[test]
+    fn test_replace_add_use_no_anchor_in_mod_mod() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+mod foo {
+    mod bar {
+        std::fmt::Debug$0
+    }
+}
+    ",
+            r"
+mod foo {
+    mod bar {
+        use std::fmt::Debug;
+
+        Debug
+    }
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn inserts_imports_after_inner_attributes() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+#![allow(dead_code)]
+
+fn main() {
+    std::fmt::Debug$0
+}
+    ",
+            r"
+#![allow(dead_code)]
+
+use std::fmt::Debug;
+
+fn main() {
+    Debug
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn replaces_all_affected_paths() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+fn main() {
+    std::fmt::Debug$0;
+    let x: std::fmt::Debug = std::fmt::Debug;
+}
+    ",
+            r"
+use std::fmt::Debug;
+
+fn main() {
+    Debug;
+    let x: Debug = Debug;
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn replaces_all_affected_paths_mod() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+mod m {
+    fn f() {
+        std::fmt::Debug$0;
+        let x: std::fmt::Debug = std::fmt::Debug;
+    }
+    fn g() {
+        std::fmt::Debug;
+    }
+}
+
+fn f() {
+    std::fmt::Debug;
+}
+    ",
+            r"
+mod m {
+    use std::fmt::Debug;
+
+    fn f() {
+        Debug;
+        let x: Debug = Debug;
+    }
+    fn g() {
+        Debug;
+    }
+}
+
+fn f() {
+    std::fmt::Debug;
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn does_not_replace_in_submodules() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+fn main() {
+    std::fmt::Debug$0;
+}
+
+mod sub {
+    fn f() {
+        std::fmt::Debug;
+    }
+}
+    ",
+            r"
+use std::fmt::Debug;
+
+fn main() {
+    Debug;
+}
+
+mod sub {
+    fn f() {
+        std::fmt::Debug;
+    }
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn does_not_replace_in_use() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+use std::fmt::Display;
+
+fn main() {
+    std::fmt$0;
+}
+    ",
+            r"
+use std::fmt::{self, Display};
+
+fn main() {
+    fmt;
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn does_not_replace_pub_use() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+pub use std::fmt;
+
+impl std::io$0 for Foo {
+}
+    ",
+            r"
+pub use std::fmt;
+use std::io;
+
+impl io for Foo {
+}
+    ",
+        );
+    }
+
+    #[test]
+    fn does_not_replace_pub_crate_use() {
+        check_assist(
+            replace_qualified_name_with_use,
+            r"
+pub(crate) use std::fmt;
+
+impl std::io$0 for Foo {
+}
+    ",
+            r"
+pub(crate) use std::fmt;
+use std::io;
+
+impl io for Foo {
+}
+    ",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/replace_string_with_char.rs b/crates/ide_assists/src/handlers/replace_string_with_char.rs
new file mode 100644
index 000000000..317318c24
--- /dev/null
+++ b/crates/ide_assists/src/handlers/replace_string_with_char.rs
@@ -0,0 +1,137 @@
+use syntax::{ast, AstToken, SyntaxKind::STRING};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: replace_string_with_char
+//
+// Replace string with char.
+//
+// ```
+// fn main() {
+//     find("{$0");
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     find('{');
+// }
+// ```
+pub(crate) fn replace_string_with_char(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let token = ctx.find_token_syntax_at_offset(STRING).and_then(ast::String::cast)?;
+    let value = token.value()?;
+    let target = token.syntax().text_range();
+
+    if value.chars().take(2).count() != 1 {
+        return None;
+    }
+
+    acc.add(
+        AssistId("replace_string_with_char", AssistKind::RefactorRewrite),
+        "Replace string with char",
+        target,
+        |edit| {
+            edit.replace(token.syntax().text_range(), format!("'{}'", value));
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn replace_string_with_char_target() {
+        check_assist_target(
+            replace_string_with_char,
+            r#"
+            fn f() {
+                let s = "$0c";
+            }
+            "#,
+            r#""c""#,
+        );
+    }
+
+    #[test]
+    fn replace_string_with_char_assist() {
+        check_assist(
+            replace_string_with_char,
+            r#"
+    fn f() {
+        let s = "$0c";
+    }
+    "#,
+            r##"
+    fn f() {
+        let s = 'c';
+    }
+    "##,
+        )
+    }
+
+    #[test]
+    fn replace_string_with_char_assist_with_emoji() {
+        check_assist(
+            replace_string_with_char,
+            r#"
+    fn f() {
+        let s = "$0😀";
+    }
+    "#,
+            r##"
+    fn f() {
+        let s = '😀';
+    }
+    "##,
+        )
+    }
+
+    #[test]
+    fn replace_string_with_char_assist_not_applicable() {
+        check_assist_not_applicable(
+            replace_string_with_char,
+            r#"
+    fn f() {
+        let s = "$0test";
+    }
+    "#,
+        )
+    }
+
+    #[test]
+    fn replace_string_with_char_works_inside_macros() {
+        check_assist(
+            replace_string_with_char,
+            r#"
+                fn f() {
+                    format!($0"x", 92)
+                }
+                "#,
+            r##"
+                fn f() {
+                    format!('x', 92)
+                }
+                "##,
+        )
+    }
+
+    #[test]
+    fn replace_string_with_char_works_func_args() {
+        check_assist(
+            replace_string_with_char,
+            r#"
+                fn f() {
+                    find($0"x");
+                }
+                "#,
+            r##"
+                fn f() {
+                    find('x');
+                }
+                "##,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/replace_unwrap_with_match.rs b/crates/ide_assists/src/handlers/replace_unwrap_with_match.rs
new file mode 100644
index 000000000..a986a6ae8
--- /dev/null
+++ b/crates/ide_assists/src/handlers/replace_unwrap_with_match.rs
@@ -0,0 +1,188 @@
+use std::iter;
+
+use syntax::{
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+        make,
+    },
+    AstNode,
+};
+
+use crate::{
+    utils::{render_snippet, Cursor},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+use ide_db::ty_filter::TryEnum;
+
+// Assist: replace_unwrap_with_match
+//
+// Replaces `unwrap` a `match` expression. Works for Result and Option.
+//
+// ```
+// enum Result<T, E> { Ok(T), Err(E) }
+// fn main() {
+//     let x: Result<i32, i32> = Result::Ok(92);
+//     let y = x.$0unwrap();
+// }
+// ```
+// ->
+// ```
+// enum Result<T, E> { Ok(T), Err(E) }
+// fn main() {
+//     let x: Result<i32, i32> = Result::Ok(92);
+//     let y = match x {
+//         Ok(a) => a,
+//         $0_ => unreachable!(),
+//     };
+// }
+// ```
+pub(crate) fn replace_unwrap_with_match(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let method_call: ast::MethodCallExpr = ctx.find_node_at_offset()?;
+    let name = method_call.name_ref()?;
+    if name.text() != "unwrap" {
+        return None;
+    }
+    let caller = method_call.receiver()?;
+    let ty = ctx.sema.type_of_expr(&caller)?;
+    let happy_variant = TryEnum::from_ty(&ctx.sema, &ty)?.happy_case();
+    let target = method_call.syntax().text_range();
+    acc.add(
+        AssistId("replace_unwrap_with_match", AssistKind::RefactorRewrite),
+        "Replace unwrap with match",
+        target,
+        |builder| {
+            let ok_path = make::path_unqualified(make::path_segment(make::name_ref(happy_variant)));
+            let it = make::ident_pat(make::name("a")).into();
+            let ok_tuple = make::tuple_struct_pat(ok_path, iter::once(it)).into();
+
+            let bind_path = make::path_unqualified(make::path_segment(make::name_ref("a")));
+            let ok_arm = make::match_arm(iter::once(ok_tuple), make::expr_path(bind_path));
+
+            let unreachable_call = make::expr_unreachable();
+            let err_arm =
+                make::match_arm(iter::once(make::wildcard_pat().into()), unreachable_call);
+
+            let match_arm_list = make::match_arm_list(vec![ok_arm, err_arm]);
+            let match_expr = make::expr_match(caller.clone(), match_arm_list)
+                .indent(IndentLevel::from_node(method_call.syntax()));
+
+            let range = method_call.syntax().text_range();
+            match ctx.config.snippet_cap {
+                Some(cap) => {
+                    let err_arm = match_expr
+                        .syntax()
+                        .descendants()
+                        .filter_map(ast::MatchArm::cast)
+                        .last()
+                        .unwrap();
+                    let snippet =
+                        render_snippet(cap, match_expr.syntax(), Cursor::Before(err_arm.syntax()));
+                    builder.replace_snippet(cap, range, snippet)
+                }
+                None => builder.replace(range, match_expr.to_string()),
+            }
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn test_replace_result_unwrap_with_match() {
+        check_assist(
+            replace_unwrap_with_match,
+            r"
+enum Result<T, E> { Ok(T), Err(E) }
+fn i<T>(a: T) -> T { a }
+fn main() {
+    let x: Result<i32, i32> = Result::Ok(92);
+    let y = i(x).$0unwrap();
+}
+            ",
+            r"
+enum Result<T, E> { Ok(T), Err(E) }
+fn i<T>(a: T) -> T { a }
+fn main() {
+    let x: Result<i32, i32> = Result::Ok(92);
+    let y = match i(x) {
+        Ok(a) => a,
+        $0_ => unreachable!(),
+    };
+}
+            ",
+        )
+    }
+
+    #[test]
+    fn test_replace_option_unwrap_with_match() {
+        check_assist(
+            replace_unwrap_with_match,
+            r"
+enum Option<T> { Some(T), None }
+fn i<T>(a: T) -> T { a }
+fn main() {
+    let x = Option::Some(92);
+    let y = i(x).$0unwrap();
+}
+            ",
+            r"
+enum Option<T> { Some(T), None }
+fn i<T>(a: T) -> T { a }
+fn main() {
+    let x = Option::Some(92);
+    let y = match i(x) {
+        Some(a) => a,
+        $0_ => unreachable!(),
+    };
+}
+            ",
+        );
+    }
+
+    #[test]
+    fn test_replace_result_unwrap_with_match_chaining() {
+        check_assist(
+            replace_unwrap_with_match,
+            r"
+enum Result<T, E> { Ok(T), Err(E) }
+fn i<T>(a: T) -> T { a }
+fn main() {
+    let x: Result<i32, i32> = Result::Ok(92);
+    let y = i(x).$0unwrap().count_zeroes();
+}
+            ",
+            r"
+enum Result<T, E> { Ok(T), Err(E) }
+fn i<T>(a: T) -> T { a }
+fn main() {
+    let x: Result<i32, i32> = Result::Ok(92);
+    let y = match i(x) {
+        Ok(a) => a,
+        $0_ => unreachable!(),
+    }.count_zeroes();
+}
+            ",
+        )
+    }
+
+    #[test]
+    fn replace_unwrap_with_match_target() {
+        check_assist_target(
+            replace_unwrap_with_match,
+            r"
+enum Option<T> { Some(T), None }
+fn i<T>(a: T) -> T { a }
+fn main() {
+    let x = Option::Some(92);
+    let y = i(x).$0unwrap();
+}
+            ",
+            r"i(x).unwrap()",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/split_import.rs b/crates/ide_assists/src/handlers/split_import.rs
new file mode 100644
index 000000000..9319a4267
--- /dev/null
+++ b/crates/ide_assists/src/handlers/split_import.rs
@@ -0,0 +1,79 @@
+use std::iter::successors;
+
+use syntax::{ast, AstNode, T};
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: split_import
+//
+// Wraps the tail of import into braces.
+//
+// ```
+// use std::$0collections::HashMap;
+// ```
+// ->
+// ```
+// use std::{collections::HashMap};
+// ```
+pub(crate) fn split_import(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let colon_colon = ctx.find_token_syntax_at_offset(T![::])?;
+    let path = ast::Path::cast(colon_colon.parent())?.qualifier()?;
+    let top_path = successors(Some(path.clone()), |it| it.parent_path()).last()?;
+
+    let use_tree = top_path.syntax().ancestors().find_map(ast::UseTree::cast)?;
+
+    let new_tree = use_tree.split_prefix(&path);
+    if new_tree == use_tree {
+        return None;
+    }
+
+    let target = colon_colon.text_range();
+    acc.add(AssistId("split_import", AssistKind::RefactorRewrite), "Split import", target, |edit| {
+        edit.replace_ast(use_tree, new_tree);
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+
+    use super::*;
+
+    #[test]
+    fn test_split_import() {
+        check_assist(
+            split_import,
+            "use crate::$0db::RootDatabase;",
+            "use crate::{db::RootDatabase};",
+        )
+    }
+
+    #[test]
+    fn split_import_works_with_trees() {
+        check_assist(
+            split_import,
+            "use crate:$0:db::{RootDatabase, FileSymbol}",
+            "use crate::{db::{RootDatabase, FileSymbol}}",
+        )
+    }
+
+    #[test]
+    fn split_import_target() {
+        check_assist_target(split_import, "use crate::$0db::{RootDatabase, FileSymbol}", "::");
+    }
+
+    #[test]
+    fn issue4044() {
+        check_assist_not_applicable(split_import, "use crate::$0:::self;")
+    }
+
+    #[test]
+    fn test_empty_use() {
+        check_assist_not_applicable(
+            split_import,
+            r"
+use std::$0
+fn main() {}",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/toggle_ignore.rs b/crates/ide_assists/src/handlers/toggle_ignore.rs
new file mode 100644
index 000000000..33e12a7d0
--- /dev/null
+++ b/crates/ide_assists/src/handlers/toggle_ignore.rs
@@ -0,0 +1,98 @@
+use syntax::{
+    ast::{self, AttrsOwner},
+    AstNode, AstToken,
+};
+
+use crate::{utils::test_related_attribute, AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: toggle_ignore
+//
+// Adds `#[ignore]` attribute to the test.
+//
+// ```
+// $0#[test]
+// fn arithmetics {
+//     assert_eq!(2 + 2, 5);
+// }
+// ```
+// ->
+// ```
+// #[test]
+// #[ignore]
+// fn arithmetics {
+//     assert_eq!(2 + 2, 5);
+// }
+// ```
+pub(crate) fn toggle_ignore(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let attr: ast::Attr = ctx.find_node_at_offset()?;
+    let func = attr.syntax().parent().and_then(ast::Fn::cast)?;
+    let attr = test_related_attribute(&func)?;
+
+    match has_ignore_attribute(&func) {
+        None => acc.add(
+            AssistId("toggle_ignore", AssistKind::None),
+            "Ignore this test",
+            attr.syntax().text_range(),
+            |builder| builder.insert(attr.syntax().text_range().end(), &format!("\n#[ignore]")),
+        ),
+        Some(ignore_attr) => acc.add(
+            AssistId("toggle_ignore", AssistKind::None),
+            "Re-enable this test",
+            ignore_attr.syntax().text_range(),
+            |builder| {
+                builder.delete(ignore_attr.syntax().text_range());
+                let whitespace = ignore_attr
+                    .syntax()
+                    .next_sibling_or_token()
+                    .and_then(|x| x.into_token())
+                    .and_then(ast::Whitespace::cast);
+                if let Some(whitespace) = whitespace {
+                    builder.delete(whitespace.syntax().text_range());
+                }
+            },
+        ),
+    }
+}
+
+fn has_ignore_attribute(fn_def: &ast::Fn) -> Option<ast::Attr> {
+    fn_def.attrs().find(|attr| attr.path().map(|it| it.syntax().text() == "ignore") == Some(true))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::check_assist;
+
+    use super::*;
+
+    #[test]
+    fn test_base_case() {
+        check_assist(
+            toggle_ignore,
+            r#"
+            #[test$0]
+            fn test() {}
+            "#,
+            r#"
+            #[test]
+            #[ignore]
+            fn test() {}
+            "#,
+        )
+    }
+
+    #[test]
+    fn test_unignore() {
+        check_assist(
+            toggle_ignore,
+            r#"
+            #[test$0]
+            #[ignore]
+            fn test() {}
+            "#,
+            r#"
+            #[test]
+            fn test() {}
+            "#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/handlers/unmerge_use.rs b/crates/ide_assists/src/handlers/unmerge_use.rs
new file mode 100644
index 000000000..3dbef8e51
--- /dev/null
+++ b/crates/ide_assists/src/handlers/unmerge_use.rs
@@ -0,0 +1,231 @@
+use syntax::{
+    algo::SyntaxRewriter,
+    ast::{self, edit::AstNodeEdit, VisibilityOwner},
+    AstNode, SyntaxKind,
+};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId, AssistKind,
+};
+
+// Assist: unmerge_use
+//
+// Extracts single use item from use list.
+//
+// ```
+// use std::fmt::{Debug, Display$0};
+// ```
+// ->
+// ```
+// use std::fmt::{Debug};
+// use std::fmt::Display;
+// ```
+pub(crate) fn unmerge_use(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let tree: ast::UseTree = ctx.find_node_at_offset()?;
+
+    let tree_list = tree.syntax().parent().and_then(ast::UseTreeList::cast)?;
+    if tree_list.use_trees().count() < 2 {
+        mark::hit!(skip_single_use_item);
+        return None;
+    }
+
+    let use_: ast::Use = tree_list.syntax().ancestors().find_map(ast::Use::cast)?;
+    let path = resolve_full_path(&tree)?;
+
+    let target = tree.syntax().text_range();
+    acc.add(
+        AssistId("unmerge_use", AssistKind::RefactorRewrite),
+        "Unmerge use",
+        target,
+        |builder| {
+            let new_use = ast::make::use_(
+                use_.visibility(),
+                ast::make::use_tree(
+                    path,
+                    tree.use_tree_list(),
+                    tree.rename(),
+                    tree.star_token().is_some(),
+                ),
+            );
+
+            let mut rewriter = SyntaxRewriter::default();
+            rewriter += tree.remove();
+            rewriter.insert_after(use_.syntax(), &ast::make::tokens::single_newline());
+            if let ident_level @ 1..=usize::MAX = use_.indent_level().0 as usize {
+                rewriter.insert_after(
+                    use_.syntax(),
+                    &ast::make::tokens::whitespace(&" ".repeat(4 * ident_level)),
+                );
+            }
+            rewriter.insert_after(use_.syntax(), new_use.syntax());
+
+            builder.rewrite(rewriter);
+        },
+    )
+}
+
+fn resolve_full_path(tree: &ast::UseTree) -> Option<ast::Path> {
+    let mut paths = tree
+        .syntax()
+        .ancestors()
+        .take_while(|n| n.kind() != SyntaxKind::USE_KW)
+        .filter_map(ast::UseTree::cast)
+        .filter_map(|t| t.path());
+
+    let mut final_path = paths.next()?;
+    for path in paths {
+        final_path = ast::make::path_concat(path, final_path)
+    }
+    Some(final_path)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn skip_single_use_item() {
+        mark::check!(skip_single_use_item);
+        check_assist_not_applicable(
+            unmerge_use,
+            r"
+use std::fmt::Debug$0;
+",
+        );
+        check_assist_not_applicable(
+            unmerge_use,
+            r"
+use std::fmt::{Debug$0};
+",
+        );
+        check_assist_not_applicable(
+            unmerge_use,
+            r"
+use std::fmt::Debug as Dbg$0;
+",
+        );
+    }
+
+    #[test]
+    fn skip_single_glob_import() {
+        check_assist_not_applicable(
+            unmerge_use,
+            r"
+use std::fmt::*$0;
+",
+        );
+    }
+
+    #[test]
+    fn unmerge_use_item() {
+        check_assist(
+            unmerge_use,
+            r"
+use std::fmt::{Debug, Display$0};
+",
+            r"
+use std::fmt::{Debug};
+use std::fmt::Display;
+",
+        );
+
+        check_assist(
+            unmerge_use,
+            r"
+use std::fmt::{Debug, format$0, Display};
+",
+            r"
+use std::fmt::{Debug, Display};
+use std::fmt::format;
+",
+        );
+    }
+
+    #[test]
+    fn unmerge_glob_import() {
+        check_assist(
+            unmerge_use,
+            r"
+use std::fmt::{*$0, Display};
+",
+            r"
+use std::fmt::{Display};
+use std::fmt::*;
+",
+        );
+    }
+
+    #[test]
+    fn unmerge_renamed_use_item() {
+        check_assist(
+            unmerge_use,
+            r"
+use std::fmt::{Debug, Display as Disp$0};
+",
+            r"
+use std::fmt::{Debug};
+use std::fmt::Display as Disp;
+",
+        );
+    }
+
+    #[test]
+    fn unmerge_indented_use_item() {
+        check_assist(
+            unmerge_use,
+            r"
+mod format {
+    use std::fmt::{Debug, Display$0 as Disp, format};
+}
+",
+            r"
+mod format {
+    use std::fmt::{Debug, format};
+    use std::fmt::Display as Disp;
+}
+",
+        );
+    }
+
+    #[test]
+    fn unmerge_nested_use_item() {
+        check_assist(
+            unmerge_use,
+            r"
+use foo::bar::{baz::{qux$0, foobar}, barbaz};
+",
+            r"
+use foo::bar::{baz::{foobar}, barbaz};
+use foo::bar::baz::qux;
+",
+        );
+        check_assist(
+            unmerge_use,
+            r"
+use foo::bar::{baz$0::{qux, foobar}, barbaz};
+",
+            r"
+use foo::bar::{barbaz};
+use foo::bar::baz::{qux, foobar};
+",
+        );
+    }
+
+    #[test]
+    fn unmerge_use_item_with_visibility() {
+        check_assist(
+            unmerge_use,
+            r"
+pub use std::fmt::{Debug, Display$0};
+",
+            r"
+pub use std::fmt::{Debug};
+pub use std::fmt::Display;
+",
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/unwrap_block.rs b/crates/ide_assists/src/handlers/unwrap_block.rs
new file mode 100644
index 000000000..ed6f6177d
--- /dev/null
+++ b/crates/ide_assists/src/handlers/unwrap_block.rs
@@ -0,0 +1,582 @@
+use syntax::{
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+    },
+    AstNode, SyntaxKind, TextRange, T,
+};
+
+use crate::{utils::unwrap_trivial_block, AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: unwrap_block
+//
+// This assist removes if...else, for, while and loop control statements to just keep the body.
+//
+// ```
+// fn foo() {
+//     if true {$0
+//         println!("foo");
+//     }
+// }
+// ```
+// ->
+// ```
+// fn foo() {
+//     println!("foo");
+// }
+// ```
+pub(crate) fn unwrap_block(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let assist_id = AssistId("unwrap_block", AssistKind::RefactorRewrite);
+    let assist_label = "Unwrap block";
+
+    let l_curly_token = ctx.find_token_syntax_at_offset(T!['{'])?;
+    let mut block = ast::BlockExpr::cast(l_curly_token.parent())?;
+    let target = block.syntax().text_range();
+    let mut parent = block.syntax().parent()?;
+    if ast::MatchArm::can_cast(parent.kind()) {
+        parent = parent.ancestors().find(|it| ast::MatchExpr::can_cast(it.kind()))?
+    }
+
+    if matches!(parent.kind(), SyntaxKind::BLOCK_EXPR | SyntaxKind::EXPR_STMT) {
+        return acc.add(assist_id, assist_label, target, |builder| {
+            builder.replace(
+                block.syntax().text_range(),
+                update_expr_string(block.to_string(), &[' ', '{', '\n']),
+            );
+        });
+    }
+
+    let parent = ast::Expr::cast(parent)?;
+
+    match parent.clone() {
+        ast::Expr::ForExpr(_) | ast::Expr::WhileExpr(_) | ast::Expr::LoopExpr(_) => (),
+        ast::Expr::MatchExpr(_) => block = block.dedent(IndentLevel(1)),
+        ast::Expr::IfExpr(if_expr) => {
+            let then_branch = if_expr.then_branch()?;
+            if then_branch == block {
+                if let Some(ancestor) = if_expr.syntax().parent().and_then(ast::IfExpr::cast) {
+                    // For `else if` blocks
+                    let ancestor_then_branch = ancestor.then_branch()?;
+
+                    return acc.add(assist_id, assist_label, target, |edit| {
+                        let range_to_del_else_if = TextRange::new(
+                            ancestor_then_branch.syntax().text_range().end(),
+                            l_curly_token.text_range().start(),
+                        );
+                        let range_to_del_rest = TextRange::new(
+                            then_branch.syntax().text_range().end(),
+                            if_expr.syntax().text_range().end(),
+                        );
+
+                        edit.delete(range_to_del_rest);
+                        edit.delete(range_to_del_else_if);
+                        edit.replace(
+                            target,
+                            update_expr_string(then_branch.to_string(), &[' ', '{']),
+                        );
+                    });
+                }
+            } else {
+                return acc.add(assist_id, assist_label, target, |edit| {
+                    let range_to_del = TextRange::new(
+                        then_branch.syntax().text_range().end(),
+                        l_curly_token.text_range().start(),
+                    );
+
+                    edit.delete(range_to_del);
+                    edit.replace(target, update_expr_string(block.to_string(), &[' ', '{']));
+                });
+            }
+        }
+        _ => return None,
+    };
+
+    let unwrapped = unwrap_trivial_block(block);
+    acc.add(assist_id, assist_label, target, |builder| {
+        builder.replace(
+            parent.syntax().text_range(),
+            update_expr_string(unwrapped.to_string(), &[' ', '{', '\n']),
+        );
+    })
+}
+
+fn update_expr_string(expr_str: String, trim_start_pat: &[char]) -> String {
+    let expr_string = expr_str.trim_start_matches(trim_start_pat);
+    let mut expr_string_lines: Vec<&str> = expr_string.lines().collect();
+    expr_string_lines.pop(); // Delete last line
+
+    expr_string_lines
+        .into_iter()
+        .map(|line| line.replacen("    ", "", 1)) // Delete indentation
+        .collect::<Vec<String>>()
+        .join("\n")
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn unwrap_tail_expr_block() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    $0{
+        92
+    }
+}
+"#,
+            r#"
+fn main() {
+    92
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn unwrap_stmt_expr_block() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    $0{
+        92;
+    }
+    ()
+}
+"#,
+            r#"
+fn main() {
+    92;
+    ()
+}
+"#,
+        );
+        // Pedantically, we should add an `;` here...
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    $0{
+        92
+    }
+    ()
+}
+"#,
+            r#"
+fn main() {
+    92
+    ()
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    bar();
+    if true {$0
+        foo();
+
+        //comment
+        bar();
+    } else {
+        println!("bar");
+    }
+}
+"#,
+            r#"
+fn main() {
+    bar();
+    foo();
+
+    //comment
+    bar();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    bar();
+    if true {
+        foo();
+
+        //comment
+        bar();
+    } else {$0
+        println!("bar");
+    }
+}
+"#,
+            r#"
+fn main() {
+    bar();
+    if true {
+        foo();
+
+        //comment
+        bar();
+    }
+    println!("bar");
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else_if() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    //bar();
+    if true {
+        println!("true");
+
+        //comment
+        //bar();
+    } else if false {$0
+        println!("bar");
+    } else {
+        println!("foo");
+    }
+}
+"#,
+            r#"
+fn main() {
+    //bar();
+    if true {
+        println!("true");
+
+        //comment
+        //bar();
+    }
+    println!("bar");
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else_if_nested() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    //bar();
+    if true {
+        println!("true");
+
+        //comment
+        //bar();
+    } else if false {
+        println!("bar");
+    } else if true {$0
+        println!("foo");
+    }
+}
+"#,
+            r#"
+fn main() {
+    //bar();
+    if true {
+        println!("true");
+
+        //comment
+        //bar();
+    } else if false {
+        println!("bar");
+    }
+    println!("foo");
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else_if_nested_else() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    //bar();
+    if true {
+        println!("true");
+
+        //comment
+        //bar();
+    } else if false {
+        println!("bar");
+    } else if true {
+        println!("foo");
+    } else {$0
+        println!("else");
+    }
+}
+"#,
+            r#"
+fn main() {
+    //bar();
+    if true {
+        println!("true");
+
+        //comment
+        //bar();
+    } else if false {
+        println!("bar");
+    } else if true {
+        println!("foo");
+    }
+    println!("else");
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else_if_nested_middle() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    //bar();
+    if true {
+        println!("true");
+
+        //comment
+        //bar();
+    } else if false {
+        println!("bar");
+    } else if true {$0
+        println!("foo");
+    } else {
+        println!("else");
+    }
+}
+"#,
+            r#"
+fn main() {
+    //bar();
+    if true {
+        println!("true");
+
+        //comment
+        //bar();
+    } else if false {
+        println!("bar");
+    }
+    println!("foo");
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if_bad_cursor_position() {
+        check_assist_not_applicable(
+            unwrap_block,
+            r#"
+fn main() {
+    bar();$0
+    if true {
+        foo();
+
+        //comment
+        bar();
+    } else {
+        println!("bar");
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_for() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    for i in 0..5 {$0
+        if true {
+            foo();
+
+            //comment
+            bar();
+        } else {
+            println!("bar");
+        }
+    }
+}
+"#,
+            r#"
+fn main() {
+    if true {
+        foo();
+
+        //comment
+        bar();
+    } else {
+        println!("bar");
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if_in_for() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    for i in 0..5 {
+        if true {$0
+            foo();
+
+            //comment
+            bar();
+        } else {
+            println!("bar");
+        }
+    }
+}
+"#,
+            r#"
+fn main() {
+    for i in 0..5 {
+        foo();
+
+        //comment
+        bar();
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_loop() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    loop {$0
+        if true {
+            foo();
+
+            //comment
+            bar();
+        } else {
+            println!("bar");
+        }
+    }
+}
+"#,
+            r#"
+fn main() {
+    if true {
+        foo();
+
+        //comment
+        bar();
+    } else {
+        println!("bar");
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_while() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    while true {$0
+        if true {
+            foo();
+
+            //comment
+            bar();
+        } else {
+            println!("bar");
+        }
+    }
+}
+"#,
+            r#"
+fn main() {
+    if true {
+        foo();
+
+        //comment
+        bar();
+    } else {
+        println!("bar");
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn unwrap_match_arm() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    match rel_path {
+        Ok(rel_path) => {$0
+            let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+            Some((*id, rel_path))
+        }
+        Err(_) => None,
+    }
+}
+"#,
+            r#"
+fn main() {
+    let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+    Some((*id, rel_path))
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn simple_if_in_while_bad_cursor_position() {
+        check_assist_not_applicable(
+            unwrap_block,
+            r#"
+fn main() {
+    while true {
+        if true {
+            foo();$0
+
+            //comment
+            bar();
+        } else {
+            println!("bar");
+        }
+    }
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/handlers/wrap_return_type_in_result.rs b/crates/ide_assists/src/handlers/wrap_return_type_in_result.rs
new file mode 100644
index 000000000..fec16fc49
--- /dev/null
+++ b/crates/ide_assists/src/handlers/wrap_return_type_in_result.rs
@@ -0,0 +1,1158 @@
+use std::iter;
+
+use syntax::{
+    ast::{self, make, BlockExpr, Expr, LoopBodyOwner},
+    match_ast, AstNode, SyntaxNode,
+};
+use test_utils::mark;
+
+use crate::{AssistContext, AssistId, AssistKind, Assists};
+
+// Assist: wrap_return_type_in_result
+//
+// Wrap the function's return type into Result.
+//
+// ```
+// fn foo() -> i32$0 { 42i32 }
+// ```
+// ->
+// ```
+// fn foo() -> Result<i32, ${0:_}> { Ok(42i32) }
+// ```
+pub(crate) fn wrap_return_type_in_result(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let ret_type = ctx.find_node_at_offset::<ast::RetType>()?;
+    let parent = ret_type.syntax().parent()?;
+    let block_expr = match_ast! {
+        match parent {
+            ast::Fn(func) => func.body()?,
+            ast::ClosureExpr(closure) => match closure.body()? {
+                Expr::BlockExpr(block) => block,
+                // closures require a block when a return type is specified
+                _ => return None,
+            },
+            _ => return None,
+        }
+    };
+
+    let type_ref = &ret_type.ty()?;
+    let ret_type_str = type_ref.syntax().text().to_string();
+    let first_part_ret_type = ret_type_str.splitn(2, '<').next();
+    if let Some(ret_type_first_part) = first_part_ret_type {
+        if ret_type_first_part.ends_with("Result") {
+            mark::hit!(wrap_return_type_in_result_simple_return_type_already_result);
+            return None;
+        }
+    }
+
+    acc.add(
+        AssistId("wrap_return_type_in_result", AssistKind::RefactorRewrite),
+        "Wrap return type in Result",
+        type_ref.syntax().text_range(),
+        |builder| {
+            let mut tail_return_expr_collector = TailReturnCollector::new();
+            tail_return_expr_collector.collect_jump_exprs(&block_expr, false);
+            tail_return_expr_collector.collect_tail_exprs(&block_expr);
+
+            for ret_expr_arg in tail_return_expr_collector.exprs_to_wrap {
+                let ok_wrapped = make::expr_call(
+                    make::expr_path(make::path_unqualified(make::path_segment(make::name_ref(
+                        "Ok",
+                    )))),
+                    make::arg_list(iter::once(ret_expr_arg.clone())),
+                );
+                builder.replace_ast(ret_expr_arg, ok_wrapped);
+            }
+
+            match ctx.config.snippet_cap {
+                Some(cap) => {
+                    let snippet = format!("Result<{}, ${{0:_}}>", type_ref);
+                    builder.replace_snippet(cap, type_ref.syntax().text_range(), snippet)
+                }
+                None => builder
+                    .replace(type_ref.syntax().text_range(), format!("Result<{}, _>", type_ref)),
+            }
+        },
+    )
+}
+
+struct TailReturnCollector {
+    exprs_to_wrap: Vec<ast::Expr>,
+}
+
+impl TailReturnCollector {
+    fn new() -> Self {
+        Self { exprs_to_wrap: vec![] }
+    }
+    /// Collect all`return` expression
+    fn collect_jump_exprs(&mut self, block_expr: &BlockExpr, collect_break: bool) {
+        let statements = block_expr.statements();
+        for stmt in statements {
+            let expr = match &stmt {
+                ast::Stmt::ExprStmt(stmt) => stmt.expr(),
+                ast::Stmt::LetStmt(stmt) => stmt.initializer(),
+                ast::Stmt::Item(_) => continue,
+            };
+            if let Some(expr) = &expr {
+                self.handle_exprs(expr, collect_break);
+            }
+        }
+
+        // Browse tail expressions for each block
+        if let Some(expr) = block_expr.tail_expr() {
+            if let Some(last_exprs) = get_tail_expr_from_block(&expr) {
+                for last_expr in last_exprs {
+                    let last_expr = match last_expr {
+                        NodeType::Node(expr) => expr,
+                        NodeType::Leaf(expr) => expr.syntax().clone(),
+                    };
+
+                    if let Some(last_expr) = Expr::cast(last_expr.clone()) {
+                        self.handle_exprs(&last_expr, collect_break);
+                    } else if let Some(expr_stmt) = ast::Stmt::cast(last_expr) {
+                        let expr_stmt = match &expr_stmt {
+                            ast::Stmt::ExprStmt(stmt) => stmt.expr(),
+                            ast::Stmt::LetStmt(stmt) => stmt.initializer(),
+                            ast::Stmt::Item(_) => None,
+                        };
+                        if let Some(expr) = &expr_stmt {
+                            self.handle_exprs(expr, collect_break);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    fn handle_exprs(&mut self, expr: &Expr, collect_break: bool) {
+        match expr {
+            Expr::BlockExpr(block_expr) => {
+                self.collect_jump_exprs(&block_expr, collect_break);
+            }
+            Expr::ReturnExpr(ret_expr) => {
+                if let Some(ret_expr_arg) = &ret_expr.expr() {
+                    self.exprs_to_wrap.push(ret_expr_arg.clone());
+                }
+            }
+            Expr::BreakExpr(break_expr) if collect_break => {
+                if let Some(break_expr_arg) = &break_expr.expr() {
+                    self.exprs_to_wrap.push(break_expr_arg.clone());
+                }
+            }
+            Expr::IfExpr(if_expr) => {
+                for block in if_expr.blocks() {
+                    self.collect_jump_exprs(&block, collect_break);
+                }
+            }
+            Expr::LoopExpr(loop_expr) => {
+                if let Some(block_expr) = loop_expr.loop_body() {
+                    self.collect_jump_exprs(&block_expr, collect_break);
+                }
+            }
+            Expr::ForExpr(for_expr) => {
+                if let Some(block_expr) = for_expr.loop_body() {
+                    self.collect_jump_exprs(&block_expr, collect_break);
+                }
+            }
+            Expr::WhileExpr(while_expr) => {
+                if let Some(block_expr) = while_expr.loop_body() {
+                    self.collect_jump_exprs(&block_expr, collect_break);
+                }
+            }
+            Expr::MatchExpr(match_expr) => {
+                if let Some(arm_list) = match_expr.match_arm_list() {
+                    arm_list.arms().filter_map(|match_arm| match_arm.expr()).for_each(|expr| {
+                        self.handle_exprs(&expr, collect_break);
+                    });
+                }
+            }
+            _ => {}
+        }
+    }
+
+    fn collect_tail_exprs(&mut self, block: &BlockExpr) {
+        if let Some(expr) = block.tail_expr() {
+            self.handle_exprs(&expr, true);
+            self.fetch_tail_exprs(&expr);
+        }
+    }
+
+    fn fetch_tail_exprs(&mut self, expr: &Expr) {
+        if let Some(exprs) = get_tail_expr_from_block(expr) {
+            for node_type in &exprs {
+                match node_type {
+                    NodeType::Leaf(expr) => {
+                        self.exprs_to_wrap.push(expr.clone());
+                    }
+                    NodeType::Node(expr) => {
+                        if let Some(last_expr) = Expr::cast(expr.clone()) {
+                            self.fetch_tail_exprs(&last_expr);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+enum NodeType {
+    Leaf(ast::Expr),
+    Node(SyntaxNode),
+}
+
+/// Get a tail expression inside a block
+fn get_tail_expr_from_block(expr: &Expr) -> Option<Vec<NodeType>> {
+    match expr {
+        Expr::IfExpr(if_expr) => {
+            let mut nodes = vec![];
+            for block in if_expr.blocks() {
+                if let Some(block_expr) = block.tail_expr() {
+                    if let Some(tail_exprs) = get_tail_expr_from_block(&block_expr) {
+                        nodes.extend(tail_exprs);
+                    }
+                } else if let Some(last_expr) = block.syntax().last_child() {
+                    nodes.push(NodeType::Node(last_expr));
+                } else {
+                    nodes.push(NodeType::Node(block.syntax().clone()));
+                }
+            }
+            Some(nodes)
+        }
+        Expr::LoopExpr(loop_expr) => {
+            loop_expr.syntax().last_child().map(|lc| vec![NodeType::Node(lc)])
+        }
+        Expr::ForExpr(for_expr) => {
+            for_expr.syntax().last_child().map(|lc| vec![NodeType::Node(lc)])
+        }
+        Expr::WhileExpr(while_expr) => {
+            while_expr.syntax().last_child().map(|lc| vec![NodeType::Node(lc)])
+        }
+        Expr::BlockExpr(block_expr) => {
+            block_expr.tail_expr().map(|lc| vec![NodeType::Node(lc.syntax().clone())])
+        }
+        Expr::MatchExpr(match_expr) => {
+            let arm_list = match_expr.match_arm_list()?;
+            let arms: Vec<NodeType> = arm_list
+                .arms()
+                .filter_map(|match_arm| match_arm.expr())
+                .map(|expr| match expr {
+                    Expr::ReturnExpr(ret_expr) => NodeType::Node(ret_expr.syntax().clone()),
+                    Expr::BreakExpr(break_expr) => NodeType::Node(break_expr.syntax().clone()),
+                    _ => match expr.syntax().last_child() {
+                        Some(last_expr) => NodeType::Node(last_expr),
+                        None => NodeType::Node(expr.syntax().clone()),
+                    },
+                })
+                .collect();
+
+            Some(arms)
+        }
+        Expr::BreakExpr(expr) => expr.expr().map(|e| vec![NodeType::Leaf(e)]),
+        Expr::ReturnExpr(ret_expr) => Some(vec![NodeType::Node(ret_expr.syntax().clone())]),
+
+        Expr::CallExpr(_)
+        | Expr::Literal(_)
+        | Expr::TupleExpr(_)
+        | Expr::ArrayExpr(_)
+        | Expr::ParenExpr(_)
+        | Expr::PathExpr(_)
+        | Expr::RecordExpr(_)
+        | Expr::IndexExpr(_)
+        | Expr::MethodCallExpr(_)
+        | Expr::AwaitExpr(_)
+        | Expr::CastExpr(_)
+        | Expr::RefExpr(_)
+        | Expr::PrefixExpr(_)
+        | Expr::RangeExpr(_)
+        | Expr::BinExpr(_)
+        | Expr::MacroCall(_)
+        | Expr::BoxExpr(_) => Some(vec![NodeType::Leaf(expr.clone())]),
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn wrap_return_type_in_result_simple() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i3$02 {
+    let test = "test";
+    return 42i32;
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let test = "test";
+    return Ok(42i32);
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_closure() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() {
+    || -> i32$0 {
+        let test = "test";
+        return 42i32;
+    };
+}
+"#,
+            r#"
+fn foo() {
+    || -> Result<i32, ${0:_}> {
+        let test = "test";
+        return Ok(42i32);
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_return_type_bad_cursor() {
+        check_assist_not_applicable(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32 {
+    let test = "test";$0
+    return 42i32;
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_return_type_bad_cursor_closure() {
+        check_assist_not_applicable(
+            wrap_return_type_in_result,
+            r#"
+fn foo() {
+    || -> i32 {
+        let test = "test";$0
+        return 42i32;
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_closure_non_block() {
+        check_assist_not_applicable(wrap_return_type_in_result, r#"fn foo() { || -> i$032 3; }"#);
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_return_type_already_result_std() {
+        check_assist_not_applicable(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> std::result::Result<i32$0, String> {
+    let test = "test";
+    return 42i32;
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_return_type_already_result() {
+        mark::check!(wrap_return_type_in_result_simple_return_type_already_result);
+        check_assist_not_applicable(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> Result<i32$0, String> {
+    let test = "test";
+    return 42i32;
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_return_type_already_result_closure() {
+        check_assist_not_applicable(
+            wrap_return_type_in_result,
+            r#"
+fn foo() {
+    || -> Result<i32$0, String> {
+        let test = "test";
+        return 42i32;
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_cursor() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> $0i32 {
+    let test = "test";
+    return 42i32;
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let test = "test";
+    return Ok(42i32);
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_tail() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() ->$0 i32 {
+    let test = "test";
+    42i32
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let test = "test";
+    Ok(42i32)
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_tail_closure() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() {
+    || ->$0 i32 {
+        let test = "test";
+        42i32
+    };
+}
+"#,
+            r#"
+fn foo() {
+    || -> Result<i32, ${0:_}> {
+        let test = "test";
+        Ok(42i32)
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_tail_only() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"fn foo() -> i32$0 { 42i32 }"#,
+            r#"fn foo() -> Result<i32, ${0:_}> { Ok(42i32) }"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_tail_block_like() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    if true {
+        42i32
+    } else {
+        24i32
+    }
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    if true {
+        Ok(42i32)
+    } else {
+        Ok(24i32)
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_without_block_closure() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() {
+    || -> i32$0 {
+        if true {
+            42i32
+        } else {
+            24i32
+        }
+    };
+}
+"#,
+            r#"
+fn foo() {
+    || -> Result<i32, ${0:_}> {
+        if true {
+            Ok(42i32)
+        } else {
+            Ok(24i32)
+        }
+    };
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_nested_if() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    if true {
+        if false {
+            1
+        } else {
+            2
+        }
+    } else {
+        24i32
+    }
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    if true {
+        if false {
+            Ok(1)
+        } else {
+            Ok(2)
+        }
+    } else {
+        Ok(24i32)
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_await() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+async fn foo() -> i$032 {
+    if true {
+        if false {
+            1.await
+        } else {
+            2.await
+        }
+    } else {
+        24i32.await
+    }
+}
+"#,
+            r#"
+async fn foo() -> Result<i32, ${0:_}> {
+    if true {
+        if false {
+            Ok(1.await)
+        } else {
+            Ok(2.await)
+        }
+    } else {
+        Ok(24i32.await)
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_array() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"fn foo() -> [i32;$0 3] { [1, 2, 3] }"#,
+            r#"fn foo() -> Result<[i32; 3], ${0:_}> { Ok([1, 2, 3]) }"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_cast() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -$0> i32 {
+    if true {
+        if false {
+            1 as i32
+        } else {
+            2 as i32
+        }
+    } else {
+        24 as i32
+    }
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    if true {
+        if false {
+            Ok(1 as i32)
+        } else {
+            Ok(2 as i32)
+        }
+    } else {
+        Ok(24 as i32)
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_tail_block_like_match() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    let my_var = 5;
+    match my_var {
+        5 => 42i32,
+        _ => 24i32,
+    }
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let my_var = 5;
+    match my_var {
+        5 => Ok(42i32),
+        _ => Ok(24i32),
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_loop_with_tail() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    let my_var = 5;
+    loop {
+        println!("test");
+        5
+    }
+    my_var
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let my_var = 5;
+    loop {
+        println!("test");
+        5
+    }
+    Ok(my_var)
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_loop_in_let_stmt() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    let my_var = let x = loop {
+        break 1;
+    };
+    my_var
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let my_var = let x = loop {
+        break 1;
+    };
+    Ok(my_var)
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_tail_block_like_match_return_expr() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    let my_var = 5;
+    let res = match my_var {
+        5 => 42i32,
+        _ => return 24i32,
+    };
+    res
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let my_var = 5;
+    let res = match my_var {
+        5 => 42i32,
+        _ => return Ok(24i32),
+    };
+    Ok(res)
+}
+"#,
+        );
+
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    let my_var = 5;
+    let res = if my_var == 5 {
+        42i32
+    } else {
+        return 24i32;
+    };
+    res
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let my_var = 5;
+    let res = if my_var == 5 {
+        42i32
+    } else {
+        return Ok(24i32);
+    };
+    Ok(res)
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_tail_block_like_match_deeper() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    let my_var = 5;
+    match my_var {
+        5 => {
+            if true {
+                42i32
+            } else {
+                25i32
+            }
+        },
+        _ => {
+            let test = "test";
+            if test == "test" {
+                return bar();
+            }
+            53i32
+        },
+    }
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let my_var = 5;
+    match my_var {
+        5 => {
+            if true {
+                Ok(42i32)
+            } else {
+                Ok(25i32)
+            }
+        },
+        _ => {
+            let test = "test";
+            if test == "test" {
+                return Ok(bar());
+            }
+            Ok(53i32)
+        },
+    }
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_tail_block_like_early_return() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i$032 {
+    let test = "test";
+    if test == "test" {
+        return 24i32;
+    }
+    53i32
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let test = "test";
+    if test == "test" {
+        return Ok(24i32);
+    }
+    Ok(53i32)
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_closure() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo(the_field: u32) ->$0 u32 {
+    let true_closure = || { return true; };
+    if the_field < 5 {
+        let mut i = 0;
+        if true_closure() {
+            return 99;
+        } else {
+            return 0;
+        }
+    }
+    the_field
+}
+"#,
+            r#"
+fn foo(the_field: u32) -> Result<u32, ${0:_}> {
+    let true_closure = || { return true; };
+    if the_field < 5 {
+        let mut i = 0;
+        if true_closure() {
+            return Ok(99);
+        } else {
+            return Ok(0);
+        }
+    }
+    Ok(the_field)
+}
+"#,
+        );
+
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+            fn foo(the_field: u32) -> u32$0 {
+                let true_closure = || {
+                    return true;
+                };
+                if the_field < 5 {
+                    let mut i = 0;
+
+
+                    if true_closure() {
+                        return 99;
+                    } else {
+                        return 0;
+                    }
+                }
+                let t = None;
+
+                t.unwrap_or_else(|| the_field)
+            }
+            "#,
+            r#"
+            fn foo(the_field: u32) -> Result<u32, ${0:_}> {
+                let true_closure = || {
+                    return true;
+                };
+                if the_field < 5 {
+                    let mut i = 0;
+
+
+                    if true_closure() {
+                        return Ok(99);
+                    } else {
+                        return Ok(0);
+                    }
+                }
+                let t = None;
+
+                Ok(t.unwrap_or_else(|| the_field))
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn wrap_return_type_in_result_simple_with_weird_forms() {
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    let test = "test";
+    if test == "test" {
+        return 24i32;
+    }
+    let mut i = 0;
+    loop {
+        if i == 1 {
+            break 55;
+        }
+        i += 1;
+    }
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let test = "test";
+    if test == "test" {
+        return Ok(24i32);
+    }
+    let mut i = 0;
+    loop {
+        if i == 1 {
+            break Ok(55);
+        }
+        i += 1;
+    }
+}
+"#,
+        );
+
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i32$0 {
+    let test = "test";
+    if test == "test" {
+        return 24i32;
+    }
+    let mut i = 0;
+    loop {
+        loop {
+            if i == 1 {
+                break 55;
+            }
+            i += 1;
+        }
+    }
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let test = "test";
+    if test == "test" {
+        return Ok(24i32);
+    }
+    let mut i = 0;
+    loop {
+        loop {
+            if i == 1 {
+                break Ok(55);
+            }
+            i += 1;
+        }
+    }
+}
+"#,
+        );
+
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo() -> i3$02 {
+    let test = "test";
+    let other = 5;
+    if test == "test" {
+        let res = match other {
+            5 => 43,
+            _ => return 56,
+        };
+    }
+    let mut i = 0;
+    loop {
+        loop {
+            if i == 1 {
+                break 55;
+            }
+            i += 1;
+        }
+    }
+}
+"#,
+            r#"
+fn foo() -> Result<i32, ${0:_}> {
+    let test = "test";
+    let other = 5;
+    if test == "test" {
+        let res = match other {
+            5 => 43,
+            _ => return Ok(56),
+        };
+    }
+    let mut i = 0;
+    loop {
+        loop {
+            if i == 1 {
+                break Ok(55);
+            }
+            i += 1;
+        }
+    }
+}
+"#,
+        );
+
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo(the_field: u32) -> u32$0 {
+    if the_field < 5 {
+        let mut i = 0;
+        loop {
+            if i > 5 {
+                return 55u32;
+            }
+            i += 3;
+        }
+        match i {
+            5 => return 99,
+            _ => return 0,
+        };
+    }
+    the_field
+}
+"#,
+            r#"
+fn foo(the_field: u32) -> Result<u32, ${0:_}> {
+    if the_field < 5 {
+        let mut i = 0;
+        loop {
+            if i > 5 {
+                return Ok(55u32);
+            }
+            i += 3;
+        }
+        match i {
+            5 => return Ok(99),
+            _ => return Ok(0),
+        };
+    }
+    Ok(the_field)
+}
+"#,
+        );
+
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo(the_field: u32) -> u3$02 {
+    if the_field < 5 {
+        let mut i = 0;
+        match i {
+            5 => return 99,
+            _ => return 0,
+        }
+    }
+    the_field
+}
+"#,
+            r#"
+fn foo(the_field: u32) -> Result<u32, ${0:_}> {
+    if the_field < 5 {
+        let mut i = 0;
+        match i {
+            5 => return Ok(99),
+            _ => return Ok(0),
+        }
+    }
+    Ok(the_field)
+}
+"#,
+        );
+
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo(the_field: u32) -> u32$0 {
+    if the_field < 5 {
+        let mut i = 0;
+        if i == 5 {
+            return 99
+        } else {
+            return 0
+        }
+    }
+    the_field
+}
+"#,
+            r#"
+fn foo(the_field: u32) -> Result<u32, ${0:_}> {
+    if the_field < 5 {
+        let mut i = 0;
+        if i == 5 {
+            return Ok(99)
+        } else {
+            return Ok(0)
+        }
+    }
+    Ok(the_field)
+}
+"#,
+        );
+
+        check_assist(
+            wrap_return_type_in_result,
+            r#"
+fn foo(the_field: u32) -> $0u32 {
+    if the_field < 5 {
+        let mut i = 0;
+        if i == 5 {
+            return 99;
+        } else {
+            return 0;
+        }
+    }
+    the_field
+}
+"#,
+            r#"
+fn foo(the_field: u32) -> Result<u32, ${0:_}> {
+    if the_field < 5 {
+        let mut i = 0;
+        if i == 5 {
+            return Ok(99);
+        } else {
+            return Ok(0);
+        }
+    }
+    Ok(the_field)
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
new file mode 100644
index 000000000..7067cf8b6
--- /dev/null
+++ b/crates/ide_assists/src/lib.rs
@@ -0,0 +1,246 @@
+//! `assists` crate provides a bunch of code assists, also known as code
+//! actions (in LSP) or intentions (in IntelliJ).
+//!
+//! An assist is a micro-refactoring, which is automatically activated in
+//! certain context. For example, if the cursor is over `,`, a "swap `,`" assist
+//! becomes available.
+
+#[allow(unused)]
+macro_rules! eprintln {
+    ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
+}
+
+mod assist_config;
+mod assist_context;
+#[cfg(test)]
+mod tests;
+pub mod utils;
+pub mod ast_transform;
+
+use hir::Semantics;
+use ide_db::base_db::FileRange;
+use ide_db::{label::Label, source_change::SourceChange, RootDatabase};
+use syntax::TextRange;
+
+pub(crate) use crate::assist_context::{AssistContext, Assists};
+
+pub use assist_config::AssistConfig;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum AssistKind {
+    None,
+    QuickFix,
+    Generate,
+    Refactor,
+    RefactorExtract,
+    RefactorInline,
+    RefactorRewrite,
+}
+
+impl AssistKind {
+    pub fn contains(self, other: AssistKind) -> bool {
+        if self == other {
+            return true;
+        }
+
+        match self {
+            AssistKind::None | AssistKind::Generate => return true,
+            AssistKind::Refactor => match other {
+                AssistKind::RefactorExtract
+                | AssistKind::RefactorInline
+                | AssistKind::RefactorRewrite => return true,
+                _ => return false,
+            },
+            _ => return false,
+        }
+    }
+}
+
+/// Unique identifier of the assist, should not be shown to the user
+/// directly.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct AssistId(pub &'static str, pub AssistKind);
+
+#[derive(Clone, Debug)]
+pub struct GroupLabel(pub String);
+
+#[derive(Debug, Clone)]
+pub struct Assist {
+    pub id: AssistId,
+    /// Short description of the assist, as shown in the UI.
+    pub label: Label,
+    pub group: Option<GroupLabel>,
+    /// Target ranges are used to sort assists: the smaller the target range,
+    /// the more specific assist is, and so it should be sorted first.
+    pub target: TextRange,
+    /// Computing source change sometimes is much more costly then computing the
+    /// other fields. Additionally, the actual change is not required to show
+    /// the lightbulb UI, it only is needed when the user tries to apply an
+    /// assist. So, we compute it lazily: the API allow requesting assists with
+    /// or without source change. We could (and in fact, used to) distinguish
+    /// between resolved and unresolved assists at the type level, but this is
+    /// cumbersome, especially if you want to embed an assist into another data
+    /// structure, such as a diagnostic.
+    pub source_change: Option<SourceChange>,
+}
+
+impl Assist {
+    /// Return all the assists applicable at the given position.
+    pub fn get(
+        db: &RootDatabase,
+        config: &AssistConfig,
+        resolve: bool,
+        range: FileRange,
+    ) -> Vec<Assist> {
+        let sema = Semantics::new(db);
+        let ctx = AssistContext::new(sema, config, range);
+        let mut acc = Assists::new(&ctx, resolve);
+        handlers::all().iter().for_each(|handler| {
+            handler(&mut acc, &ctx);
+        });
+        acc.finish()
+    }
+}
+
+mod handlers {
+    use crate::{AssistContext, Assists};
+
+    pub(crate) type Handler = fn(&mut Assists, &AssistContext) -> Option<()>;
+
+    mod add_explicit_type;
+    mod add_lifetime_to_type;
+    mod add_missing_impl_members;
+    mod add_turbo_fish;
+    mod apply_demorgan;
+    mod auto_import;
+    mod change_visibility;
+    mod convert_integer_literal;
+    mod early_return;
+    mod expand_glob_import;
+    mod extract_function;
+    mod extract_struct_from_enum_variant;
+    mod extract_variable;
+    mod fill_match_arms;
+    mod fix_visibility;
+    mod flip_binexpr;
+    mod flip_comma;
+    mod flip_trait_bound;
+    mod generate_default_from_enum_variant;
+    mod generate_derive;
+    mod generate_enum_match_method;
+    mod generate_from_impl_for_enum;
+    mod generate_function;
+    mod generate_getter;
+    mod generate_getter_mut;
+    mod generate_impl;
+    mod generate_new;
+    mod generate_setter;
+    mod infer_function_return_type;
+    mod inline_function;
+    mod inline_local_variable;
+    mod introduce_named_lifetime;
+    mod invert_if;
+    mod merge_imports;
+    mod merge_match_arms;
+    mod move_bounds;
+    mod move_guard;
+    mod move_module_to_file;
+    mod pull_assignment_up;
+    mod qualify_path;
+    mod raw_string;
+    mod remove_dbg;
+    mod remove_mut;
+    mod remove_unused_param;
+    mod reorder_fields;
+    mod reorder_impl;
+    mod replace_derive_with_manual_impl;
+    mod replace_if_let_with_match;
+    mod replace_impl_trait_with_generic;
+    mod replace_let_with_if_let;
+    mod replace_qualified_name_with_use;
+    mod replace_string_with_char;
+    mod replace_unwrap_with_match;
+    mod split_import;
+    mod toggle_ignore;
+    mod unmerge_use;
+    mod unwrap_block;
+    mod wrap_return_type_in_result;
+
+    pub(crate) fn all() -> &'static [Handler] {
+        &[
+            // These are alphabetic for the foolish consistency
+            add_explicit_type::add_explicit_type,
+            add_lifetime_to_type::add_lifetime_to_type,
+            add_turbo_fish::add_turbo_fish,
+            apply_demorgan::apply_demorgan,
+            auto_import::auto_import,
+            change_visibility::change_visibility,
+            convert_integer_literal::convert_integer_literal,
+            early_return::convert_to_guarded_return,
+            expand_glob_import::expand_glob_import,
+            move_module_to_file::move_module_to_file,
+            extract_struct_from_enum_variant::extract_struct_from_enum_variant,
+            fill_match_arms::fill_match_arms,
+            fix_visibility::fix_visibility,
+            flip_binexpr::flip_binexpr,
+            flip_comma::flip_comma,
+            flip_trait_bound::flip_trait_bound,
+            generate_default_from_enum_variant::generate_default_from_enum_variant,
+            generate_derive::generate_derive,
+            generate_enum_match_method::generate_enum_match_method,
+            generate_from_impl_for_enum::generate_from_impl_for_enum,
+            generate_function::generate_function,
+            generate_getter::generate_getter,
+            generate_getter_mut::generate_getter_mut,
+            generate_impl::generate_impl,
+            generate_new::generate_new,
+            generate_setter::generate_setter,
+            infer_function_return_type::infer_function_return_type,
+            inline_function::inline_function,
+            inline_local_variable::inline_local_variable,
+            introduce_named_lifetime::introduce_named_lifetime,
+            invert_if::invert_if,
+            merge_imports::merge_imports,
+            merge_match_arms::merge_match_arms,
+            move_bounds::move_bounds_to_where_clause,
+            move_guard::move_arm_cond_to_match_guard,
+            move_guard::move_guard_to_arm_body,
+            pull_assignment_up::pull_assignment_up,
+            qualify_path::qualify_path,
+            raw_string::add_hash,
+            raw_string::make_usual_string,
+            raw_string::remove_hash,
+            remove_dbg::remove_dbg,
+            remove_mut::remove_mut,
+            remove_unused_param::remove_unused_param,
+            reorder_fields::reorder_fields,
+            reorder_impl::reorder_impl,
+            replace_derive_with_manual_impl::replace_derive_with_manual_impl,
+            replace_if_let_with_match::replace_if_let_with_match,
+            replace_if_let_with_match::replace_match_with_if_let,
+            replace_impl_trait_with_generic::replace_impl_trait_with_generic,
+            replace_let_with_if_let::replace_let_with_if_let,
+            replace_qualified_name_with_use::replace_qualified_name_with_use,
+            replace_unwrap_with_match::replace_unwrap_with_match,
+            split_import::split_import,
+            toggle_ignore::toggle_ignore,
+            unmerge_use::unmerge_use,
+            unwrap_block::unwrap_block,
+            wrap_return_type_in_result::wrap_return_type_in_result,
+            // These are manually sorted for better priorities. By default,
+            // priority is determined by the size of the target range (smaller
+            // target wins). If the ranges are equal, position in this list is
+            // used as a tie-breaker.
+            add_missing_impl_members::add_missing_impl_members,
+            add_missing_impl_members::add_missing_default_members,
+            //
+            replace_string_with_char::replace_string_with_char,
+            raw_string::make_raw_string,
+            //
+            extract_variable::extract_variable,
+            extract_function::extract_function,
+            // Are you sure you want to add new assist here, and not to the
+            // sorted list above?
+        ]
+    }
+}
diff --git a/crates/ide_assists/src/tests.rs b/crates/ide_assists/src/tests.rs
new file mode 100644
index 000000000..384eb7eee
--- /dev/null
+++ b/crates/ide_assists/src/tests.rs
@@ -0,0 +1,275 @@
+mod generated;
+
+use expect_test::expect;
+use hir::Semantics;
+use ide_db::{
+    base_db::{fixture::WithFixture, FileId, FileRange, SourceDatabaseExt},
+    helpers::{
+        insert_use::{InsertUseConfig, MergeBehavior},
+        SnippetCap,
+    },
+    source_change::FileSystemEdit,
+    RootDatabase,
+};
+use stdx::{format_to, trim_indent};
+use syntax::TextRange;
+use test_utils::{assert_eq_text, extract_offset};
+
+use crate::{handlers::Handler, Assist, AssistConfig, AssistContext, AssistKind, Assists};
+
+pub(crate) const TEST_CONFIG: AssistConfig = AssistConfig {
+    snippet_cap: SnippetCap::new(true),
+    allowed: None,
+    insert_use: InsertUseConfig {
+        merge: Some(MergeBehavior::Full),
+        prefix_kind: hir::PrefixKind::Plain,
+    },
+};
+
+pub(crate) fn with_single_file(text: &str) -> (RootDatabase, FileId) {
+    RootDatabase::with_single_file(text)
+}
+
+pub(crate) fn check_assist(assist: Handler, ra_fixture_before: &str, ra_fixture_after: &str) {
+    let ra_fixture_after = trim_indent(ra_fixture_after);
+    check(assist, ra_fixture_before, ExpectedResult::After(&ra_fixture_after), None);
+}
+
+// There is no way to choose what assist within a group you want to test against,
+// so this is here to allow you choose.
+pub(crate) fn check_assist_by_label(
+    assist: Handler,
+    ra_fixture_before: &str,
+    ra_fixture_after: &str,
+    label: &str,
+) {
+    let ra_fixture_after = trim_indent(ra_fixture_after);
+    check(assist, ra_fixture_before, ExpectedResult::After(&ra_fixture_after), Some(label));
+}
+
+// FIXME: instead of having a separate function here, maybe use
+// `extract_ranges` and mark the target as `<target> </target>` in the
+// fixture?
+#[track_caller]
+pub(crate) fn check_assist_target(assist: Handler, ra_fixture: &str, target: &str) {
+    check(assist, ra_fixture, ExpectedResult::Target(target), None);
+}
+
+#[track_caller]
+pub(crate) fn check_assist_not_applicable(assist: Handler, ra_fixture: &str) {
+    check(assist, ra_fixture, ExpectedResult::NotApplicable, None);
+}
+
+#[track_caller]
+fn check_doc_test(assist_id: &str, before: &str, after: &str) {
+    let after = trim_indent(after);
+    let (db, file_id, selection) = RootDatabase::with_range_or_offset(&before);
+    let before = db.file_text(file_id).to_string();
+    let frange = FileRange { file_id, range: selection.into() };
+
+    let assist = Assist::get(&db, &TEST_CONFIG, true, frange)
+        .into_iter()
+        .find(|assist| assist.id.0 == assist_id)
+        .unwrap_or_else(|| {
+            panic!(
+                "\n\nAssist is not applicable: {}\nAvailable assists: {}",
+                assist_id,
+                Assist::get(&db, &TEST_CONFIG, false, frange)
+                    .into_iter()
+                    .map(|assist| assist.id.0)
+                    .collect::<Vec<_>>()
+                    .join(", ")
+            )
+        });
+
+    let actual = {
+        let source_change = assist.source_change.unwrap();
+        let mut actual = before;
+        if let Some(source_file_edit) = source_change.get_source_edit(file_id) {
+            source_file_edit.apply(&mut actual);
+        }
+        actual
+    };
+    assert_eq_text!(&after, &actual);
+}
+
+enum ExpectedResult<'a> {
+    NotApplicable,
+    After(&'a str),
+    Target(&'a str),
+}
+
+#[track_caller]
+fn check(handler: Handler, before: &str, expected: ExpectedResult, assist_label: Option<&str>) {
+    let (db, file_with_caret_id, range_or_offset) = RootDatabase::with_range_or_offset(before);
+    let text_without_caret = db.file_text(file_with_caret_id).to_string();
+
+    let frange = FileRange { file_id: file_with_caret_id, range: range_or_offset.into() };
+
+    let sema = Semantics::new(&db);
+    let config = TEST_CONFIG;
+    let ctx = AssistContext::new(sema, &config, frange);
+    let mut acc = Assists::new(&ctx, true);
+    handler(&mut acc, &ctx);
+    let mut res = acc.finish();
+
+    let assist = match assist_label {
+        Some(label) => res.into_iter().find(|resolved| resolved.label == label),
+        None => res.pop(),
+    };
+
+    match (assist, expected) {
+        (Some(assist), ExpectedResult::After(after)) => {
+            let source_change = assist.source_change.unwrap();
+            assert!(!source_change.source_file_edits.is_empty());
+            let skip_header = source_change.source_file_edits.len() == 1
+                && source_change.file_system_edits.len() == 0;
+
+            let mut buf = String::new();
+            for (file_id, edit) in source_change.source_file_edits {
+                let mut text = db.file_text(file_id).as_ref().to_owned();
+                edit.apply(&mut text);
+                if !skip_header {
+                    let sr = db.file_source_root(file_id);
+                    let sr = db.source_root(sr);
+                    let path = sr.path_for_file(&file_id).unwrap();
+                    format_to!(buf, "//- {}\n", path)
+                }
+                buf.push_str(&text);
+            }
+
+            for file_system_edit in source_change.file_system_edits {
+                if let FileSystemEdit::CreateFile { dst, initial_contents } = file_system_edit {
+                    let sr = db.file_source_root(dst.anchor);
+                    let sr = db.source_root(sr);
+                    let mut base = sr.path_for_file(&dst.anchor).unwrap().clone();
+                    base.pop();
+                    let created_file_path = format!("{}{}", base.to_string(), &dst.path[1..]);
+                    format_to!(buf, "//- {}\n", created_file_path);
+                    buf.push_str(&initial_contents);
+                }
+            }
+
+            assert_eq_text!(after, &buf);
+        }
+        (Some(assist), ExpectedResult::Target(target)) => {
+            let range = assist.target;
+            assert_eq_text!(&text_without_caret[range], target);
+        }
+        (Some(_), ExpectedResult::NotApplicable) => panic!("assist should not be applicable!"),
+        (None, ExpectedResult::After(_)) | (None, ExpectedResult::Target(_)) => {
+            panic!("code action is not applicable")
+        }
+        (None, ExpectedResult::NotApplicable) => (),
+    };
+}
+
+fn labels(assists: &[Assist]) -> String {
+    let mut labels = assists
+        .iter()
+        .map(|assist| {
+            let mut label = match &assist.group {
+                Some(g) => g.0.clone(),
+                None => assist.label.to_string(),
+            };
+            label.push('\n');
+            label
+        })
+        .collect::<Vec<_>>();
+    labels.dedup();
+    labels.into_iter().collect::<String>()
+}
+
+#[test]
+fn assist_order_field_struct() {
+    let before = "struct Foo { $0bar: u32 }";
+    let (before_cursor_pos, before) = extract_offset(before);
+    let (db, file_id) = with_single_file(&before);
+    let frange = FileRange { file_id, range: TextRange::empty(before_cursor_pos) };
+    let assists = Assist::get(&db, &TEST_CONFIG, false, frange);
+    let mut assists = assists.iter();
+
+    assert_eq!(assists.next().expect("expected assist").label, "Change visibility to pub(crate)");
+    assert_eq!(assists.next().expect("expected assist").label, "Generate a getter method");
+    assert_eq!(assists.next().expect("expected assist").label, "Generate a mut getter method");
+    assert_eq!(assists.next().expect("expected assist").label, "Generate a setter method");
+    assert_eq!(assists.next().expect("expected assist").label, "Add `#[derive]`");
+}
+
+#[test]
+fn assist_order_if_expr() {
+    let (db, frange) = RootDatabase::with_range(
+        r#"
+pub fn test_some_range(a: int) -> bool {
+    if let 2..6 = $05$0 {
+        true
+    } else {
+        false
+    }
+}
+"#,
+    );
+
+    let assists = Assist::get(&db, &TEST_CONFIG, false, frange);
+    let expected = labels(&assists);
+
+    expect![[r#"
+        Convert integer base
+        Extract into variable
+        Extract into function
+        Replace with match
+    "#]]
+    .assert_eq(&expected);
+}
+
+#[test]
+fn assist_filter_works() {
+    let (db, frange) = RootDatabase::with_range(
+        r#"
+pub fn test_some_range(a: int) -> bool {
+    if let 2..6 = $05$0 {
+        true
+    } else {
+        false
+    }
+}
+"#,
+    );
+    {
+        let mut cfg = TEST_CONFIG;
+        cfg.allowed = Some(vec![AssistKind::Refactor]);
+
+        let assists = Assist::get(&db, &cfg, false, frange);
+        let expected = labels(&assists);
+
+        expect![[r#"
+            Convert integer base
+            Extract into variable
+            Extract into function
+            Replace with match
+        "#]]
+        .assert_eq(&expected);
+    }
+
+    {
+        let mut cfg = TEST_CONFIG;
+        cfg.allowed = Some(vec![AssistKind::RefactorExtract]);
+        let assists = Assist::get(&db, &cfg, false, frange);
+        let expected = labels(&assists);
+
+        expect![[r#"
+            Extract into variable
+            Extract into function
+        "#]]
+        .assert_eq(&expected);
+    }
+
+    {
+        let mut cfg = TEST_CONFIG;
+        cfg.allowed = Some(vec![AssistKind::QuickFix]);
+        let assists = Assist::get(&db, &cfg, false, frange);
+        let expected = labels(&assists);
+
+        expect![[r#""#]].assert_eq(&expected);
+    }
+}
diff --git a/crates/ide_assists/src/tests/generated.rs b/crates/ide_assists/src/tests/generated.rs
new file mode 100644
index 000000000..0516deaff
--- /dev/null
+++ b/crates/ide_assists/src/tests/generated.rs
@@ -0,0 +1,1329 @@
+//! Generated file, do not edit by hand, see `xtask/src/codegen`
+
+use super::check_doc_test;
+
+#[test]
+fn doctest_add_explicit_type() {
+    check_doc_test(
+        "add_explicit_type",
+        r#####"
+fn main() {
+    let x$0 = 92;
+}
+"#####,
+        r#####"
+fn main() {
+    let x: i32 = 92;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_add_hash() {
+    check_doc_test(
+        "add_hash",
+        r#####"
+fn main() {
+    r#"Hello,$0 World!"#;
+}
+"#####,
+        r#####"
+fn main() {
+    r##"Hello, World!"##;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_add_impl_default_members() {
+    check_doc_test(
+        "add_impl_default_members",
+        r#####"
+trait Trait {
+    type X;
+    fn foo(&self);
+    fn bar(&self) {}
+}
+
+impl Trait for () {
+    type X = ();
+    fn foo(&self) {}$0
+
+}
+"#####,
+        r#####"
+trait Trait {
+    type X;
+    fn foo(&self);
+    fn bar(&self) {}
+}
+
+impl Trait for () {
+    type X = ();
+    fn foo(&self) {}
+
+    $0fn bar(&self) {}
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_add_impl_missing_members() {
+    check_doc_test(
+        "add_impl_missing_members",
+        r#####"
+trait Trait<T> {
+    type X;
+    fn foo(&self) -> T;
+    fn bar(&self) {}
+}
+
+impl Trait<u32> for () {$0
+
+}
+"#####,
+        r#####"
+trait Trait<T> {
+    type X;
+    fn foo(&self) -> T;
+    fn bar(&self) {}
+}
+
+impl Trait<u32> for () {
+    $0type X;
+
+    fn foo(&self) -> u32 {
+        todo!()
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_add_lifetime_to_type() {
+    check_doc_test(
+        "add_lifetime_to_type",
+        r#####"
+struct Point {
+    x: &$0u32,
+    y: u32,
+}
+"#####,
+        r#####"
+struct Point<'a> {
+    x: &'a u32,
+    y: u32,
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_add_turbo_fish() {
+    check_doc_test(
+        "add_turbo_fish",
+        r#####"
+fn make<T>() -> T { todo!() }
+fn main() {
+    let x = make$0();
+}
+"#####,
+        r#####"
+fn make<T>() -> T { todo!() }
+fn main() {
+    let x = make::<${0:_}>();
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_apply_demorgan() {
+    check_doc_test(
+        "apply_demorgan",
+        r#####"
+fn main() {
+    if x != 4 ||$0 !y {}
+}
+"#####,
+        r#####"
+fn main() {
+    if !(x == 4 && y) {}
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_auto_import() {
+    check_doc_test(
+        "auto_import",
+        r#####"
+fn main() {
+    let map = HashMap$0::new();
+}
+pub mod std { pub mod collections { pub struct HashMap { } } }
+"#####,
+        r#####"
+use std::collections::HashMap;
+
+fn main() {
+    let map = HashMap::new();
+}
+pub mod std { pub mod collections { pub struct HashMap { } } }
+"#####,
+    )
+}
+
+#[test]
+fn doctest_change_visibility() {
+    check_doc_test(
+        "change_visibility",
+        r#####"
+$0fn frobnicate() {}
+"#####,
+        r#####"
+pub(crate) fn frobnicate() {}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_convert_integer_literal() {
+    check_doc_test(
+        "convert_integer_literal",
+        r#####"
+const _: i32 = 10$0;
+"#####,
+        r#####"
+const _: i32 = 0b1010;
+"#####,
+    )
+}
+
+#[test]
+fn doctest_convert_to_guarded_return() {
+    check_doc_test(
+        "convert_to_guarded_return",
+        r#####"
+fn main() {
+    $0if cond {
+        foo();
+        bar();
+    }
+}
+"#####,
+        r#####"
+fn main() {
+    if !cond {
+        return;
+    }
+    foo();
+    bar();
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_expand_glob_import() {
+    check_doc_test(
+        "expand_glob_import",
+        r#####"
+mod foo {
+    pub struct Bar;
+    pub struct Baz;
+}
+
+use foo::*$0;
+
+fn qux(bar: Bar, baz: Baz) {}
+"#####,
+        r#####"
+mod foo {
+    pub struct Bar;
+    pub struct Baz;
+}
+
+use foo::{Baz, Bar};
+
+fn qux(bar: Bar, baz: Baz) {}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_extract_function() {
+    check_doc_test(
+        "extract_function",
+        r#####"
+fn main() {
+    let n = 1;
+    $0let m = n + 2;
+    let k = m + n;$0
+    let g = 3;
+}
+"#####,
+        r#####"
+fn main() {
+    let n = 1;
+    fun_name(n);
+    let g = 3;
+}
+
+fn $0fun_name(n: i32) {
+    let m = n + 2;
+    let k = m + n;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_extract_struct_from_enum_variant() {
+    check_doc_test(
+        "extract_struct_from_enum_variant",
+        r#####"
+enum A { $0One(u32, u32) }
+"#####,
+        r#####"
+struct One(pub u32, pub u32);
+
+enum A { One(One) }
+"#####,
+    )
+}
+
+#[test]
+fn doctest_extract_variable() {
+    check_doc_test(
+        "extract_variable",
+        r#####"
+fn main() {
+    $0(1 + 2)$0 * 4;
+}
+"#####,
+        r#####"
+fn main() {
+    let $0var_name = (1 + 2);
+    var_name * 4;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_fill_match_arms() {
+    check_doc_test(
+        "fill_match_arms",
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        $0
+    }
+}
+"#####,
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        $0Action::Move { distance } => {}
+        Action::Stop => {}
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_fix_visibility() {
+    check_doc_test(
+        "fix_visibility",
+        r#####"
+mod m {
+    fn frobnicate() {}
+}
+fn main() {
+    m::frobnicate$0() {}
+}
+"#####,
+        r#####"
+mod m {
+    $0pub(crate) fn frobnicate() {}
+}
+fn main() {
+    m::frobnicate() {}
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_flip_binexpr() {
+    check_doc_test(
+        "flip_binexpr",
+        r#####"
+fn main() {
+    let _ = 90 +$0 2;
+}
+"#####,
+        r#####"
+fn main() {
+    let _ = 2 + 90;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_flip_comma() {
+    check_doc_test(
+        "flip_comma",
+        r#####"
+fn main() {
+    ((1, 2),$0 (3, 4));
+}
+"#####,
+        r#####"
+fn main() {
+    ((3, 4), (1, 2));
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_flip_trait_bound() {
+    check_doc_test(
+        "flip_trait_bound",
+        r#####"
+fn foo<T: Clone +$0 Copy>() { }
+"#####,
+        r#####"
+fn foo<T: Copy + Clone>() { }
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_default_from_enum_variant() {
+    check_doc_test(
+        "generate_default_from_enum_variant",
+        r#####"
+enum Version {
+ Undefined,
+ Minor$0,
+ Major,
+}
+"#####,
+        r#####"
+enum Version {
+ Undefined,
+ Minor,
+ Major,
+}
+
+impl Default for Version {
+    fn default() -> Self {
+        Self::Minor
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_derive() {
+    check_doc_test(
+        "generate_derive",
+        r#####"
+struct Point {
+    x: u32,
+    y: u32,$0
+}
+"#####,
+        r#####"
+#[derive($0)]
+struct Point {
+    x: u32,
+    y: u32,
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_enum_match_method() {
+    check_doc_test(
+        "generate_enum_match_method",
+        r#####"
+enum Version {
+ Undefined,
+ Minor$0,
+ Major,
+}
+"#####,
+        r#####"
+enum Version {
+ Undefined,
+ Minor,
+ Major,
+}
+
+impl Version {
+    /// Returns `true` if the version is [`Minor`].
+    fn is_minor(&self) -> bool {
+        matches!(self, Self::Minor)
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_from_impl_for_enum() {
+    check_doc_test(
+        "generate_from_impl_for_enum",
+        r#####"
+enum A { $0One(u32) }
+"#####,
+        r#####"
+enum A { One(u32) }
+
+impl From<u32> for A {
+    fn from(v: u32) -> Self {
+        Self::One(v)
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_function() {
+    check_doc_test(
+        "generate_function",
+        r#####"
+struct Baz;
+fn baz() -> Baz { Baz }
+fn foo() {
+    bar$0("", baz());
+}
+
+"#####,
+        r#####"
+struct Baz;
+fn baz() -> Baz { Baz }
+fn foo() {
+    bar("", baz());
+}
+
+fn bar(arg: &str, baz: Baz) ${0:-> ()} {
+    todo!()
+}
+
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_getter() {
+    check_doc_test(
+        "generate_getter",
+        r#####"
+struct Person {
+    nam$0e: String,
+}
+"#####,
+        r#####"
+struct Person {
+    name: String,
+}
+
+impl Person {
+    /// Get a reference to the person's name.
+    fn name(&self) -> &String {
+        &self.name
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_getter_mut() {
+    check_doc_test(
+        "generate_getter_mut",
+        r#####"
+struct Person {
+    nam$0e: String,
+}
+"#####,
+        r#####"
+struct Person {
+    name: String,
+}
+
+impl Person {
+    /// Get a mutable reference to the person's name.
+    fn name_mut(&mut self) -> &mut String {
+        &mut self.name
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_impl() {
+    check_doc_test(
+        "generate_impl",
+        r#####"
+struct Ctx<T: Clone> {
+    data: T,$0
+}
+"#####,
+        r#####"
+struct Ctx<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Ctx<T> {
+    $0
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_new() {
+    check_doc_test(
+        "generate_new",
+        r#####"
+struct Ctx<T: Clone> {
+     data: T,$0
+}
+"#####,
+        r#####"
+struct Ctx<T: Clone> {
+     data: T,
+}
+
+impl<T: Clone> Ctx<T> {
+    fn $0new(data: T) -> Self { Self { data } }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_generate_setter() {
+    check_doc_test(
+        "generate_setter",
+        r#####"
+struct Person {
+    nam$0e: String,
+}
+"#####,
+        r#####"
+struct Person {
+    name: String,
+}
+
+impl Person {
+    /// Set the person's name.
+    fn set_name(&mut self, name: String) {
+        self.name = name;
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_infer_function_return_type() {
+    check_doc_test(
+        "infer_function_return_type",
+        r#####"
+fn foo() { 4$02i32 }
+"#####,
+        r#####"
+fn foo() -> i32 { 42i32 }
+"#####,
+    )
+}
+
+#[test]
+fn doctest_inline_function() {
+    check_doc_test(
+        "inline_function",
+        r#####"
+fn add(a: u32, b: u32) -> u32 { a + b }
+fn main() {
+    let x = add$0(1, 2);
+}
+"#####,
+        r#####"
+fn add(a: u32, b: u32) -> u32 { a + b }
+fn main() {
+    let x = {
+        let a = 1;
+        let b = 2;
+        a + b
+    };
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_inline_local_variable() {
+    check_doc_test(
+        "inline_local_variable",
+        r#####"
+fn main() {
+    let x$0 = 1 + 2;
+    x * 4;
+}
+"#####,
+        r#####"
+fn main() {
+    (1 + 2) * 4;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_introduce_named_lifetime() {
+    check_doc_test(
+        "introduce_named_lifetime",
+        r#####"
+impl Cursor<'_$0> {
+    fn node(self) -> &SyntaxNode {
+        match self {
+            Cursor::Replace(node) | Cursor::Before(node) => node,
+        }
+    }
+}
+"#####,
+        r#####"
+impl<'a> Cursor<'a> {
+    fn node(self) -> &SyntaxNode {
+        match self {
+            Cursor::Replace(node) | Cursor::Before(node) => node,
+        }
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_invert_if() {
+    check_doc_test(
+        "invert_if",
+        r#####"
+fn main() {
+    if$0 !y { A } else { B }
+}
+"#####,
+        r#####"
+fn main() {
+    if y { B } else { A }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_make_raw_string() {
+    check_doc_test(
+        "make_raw_string",
+        r#####"
+fn main() {
+    "Hello,$0 World!";
+}
+"#####,
+        r#####"
+fn main() {
+    r#"Hello, World!"#;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_make_usual_string() {
+    check_doc_test(
+        "make_usual_string",
+        r#####"
+fn main() {
+    r#"Hello,$0 "World!""#;
+}
+"#####,
+        r#####"
+fn main() {
+    "Hello, \"World!\"";
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_merge_imports() {
+    check_doc_test(
+        "merge_imports",
+        r#####"
+use std::$0fmt::Formatter;
+use std::io;
+"#####,
+        r#####"
+use std::{fmt::Formatter, io};
+"#####,
+    )
+}
+
+#[test]
+fn doctest_merge_match_arms() {
+    check_doc_test(
+        "merge_match_arms",
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        $0Action::Move(..) => foo(),
+        Action::Stop => foo(),
+    }
+}
+"#####,
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move(..) | Action::Stop => foo(),
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_move_arm_cond_to_match_guard() {
+    check_doc_test(
+        "move_arm_cond_to_match_guard",
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move { distance } => $0if distance > 10 { foo() },
+        _ => (),
+    }
+}
+"#####,
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move { distance } if distance > 10 => foo(),
+        _ => (),
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_move_bounds_to_where_clause() {
+    check_doc_test(
+        "move_bounds_to_where_clause",
+        r#####"
+fn apply<T, U, $0F: FnOnce(T) -> U>(f: F, x: T) -> U {
+    f(x)
+}
+"#####,
+        r#####"
+fn apply<T, U, F>(f: F, x: T) -> U where F: FnOnce(T) -> U {
+    f(x)
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_move_guard_to_arm_body() {
+    check_doc_test(
+        "move_guard_to_arm_body",
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move { distance } $0if distance > 10 => foo(),
+        _ => (),
+    }
+}
+"#####,
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move { distance } => if distance > 10 {
+            foo()
+        },
+        _ => (),
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_move_module_to_file() {
+    check_doc_test(
+        "move_module_to_file",
+        r#####"
+mod $0foo {
+    fn t() {}
+}
+"#####,
+        r#####"
+mod foo;
+"#####,
+    )
+}
+
+#[test]
+fn doctest_pull_assignment_up() {
+    check_doc_test(
+        "pull_assignment_up",
+        r#####"
+fn main() {
+    let mut foo = 6;
+
+    if true {
+        $0foo = 5;
+    } else {
+        foo = 4;
+    }
+}
+"#####,
+        r#####"
+fn main() {
+    let mut foo = 6;
+
+    foo = if true {
+        5
+    } else {
+        4
+    };
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_qualify_path() {
+    check_doc_test(
+        "qualify_path",
+        r#####"
+fn main() {
+    let map = HashMap$0::new();
+}
+pub mod std { pub mod collections { pub struct HashMap { } } }
+"#####,
+        r#####"
+fn main() {
+    let map = std::collections::HashMap::new();
+}
+pub mod std { pub mod collections { pub struct HashMap { } } }
+"#####,
+    )
+}
+
+#[test]
+fn doctest_remove_dbg() {
+    check_doc_test(
+        "remove_dbg",
+        r#####"
+fn main() {
+    $0dbg!(92);
+}
+"#####,
+        r#####"
+fn main() {
+    92;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_remove_hash() {
+    check_doc_test(
+        "remove_hash",
+        r#####"
+fn main() {
+    r#"Hello,$0 World!"#;
+}
+"#####,
+        r#####"
+fn main() {
+    r"Hello, World!";
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_remove_mut() {
+    check_doc_test(
+        "remove_mut",
+        r#####"
+impl Walrus {
+    fn feed(&mut$0 self, amount: u32) {}
+}
+"#####,
+        r#####"
+impl Walrus {
+    fn feed(&self, amount: u32) {}
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_remove_unused_param() {
+    check_doc_test(
+        "remove_unused_param",
+        r#####"
+fn frobnicate(x: i32$0) {}
+
+fn main() {
+    frobnicate(92);
+}
+"#####,
+        r#####"
+fn frobnicate() {}
+
+fn main() {
+    frobnicate();
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_reorder_fields() {
+    check_doc_test(
+        "reorder_fields",
+        r#####"
+struct Foo {foo: i32, bar: i32};
+const test: Foo = $0Foo {bar: 0, foo: 1}
+"#####,
+        r#####"
+struct Foo {foo: i32, bar: i32};
+const test: Foo = Foo {foo: 1, bar: 0}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_reorder_impl() {
+    check_doc_test(
+        "reorder_impl",
+        r#####"
+trait Foo {
+    fn a() {}
+    fn b() {}
+    fn c() {}
+}
+
+struct Bar;
+$0impl Foo for Bar {
+    fn b() {}
+    fn c() {}
+    fn a() {}
+}
+"#####,
+        r#####"
+trait Foo {
+    fn a() {}
+    fn b() {}
+    fn c() {}
+}
+
+struct Bar;
+impl Foo for Bar {
+    fn a() {}
+    fn b() {}
+    fn c() {}
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_derive_with_manual_impl() {
+    check_doc_test(
+        "replace_derive_with_manual_impl",
+        r#####"
+trait Debug { fn fmt(&self, f: &mut Formatter) -> Result<()>; }
+#[derive(Deb$0ug, Display)]
+struct S;
+"#####,
+        r#####"
+trait Debug { fn fmt(&self, f: &mut Formatter) -> Result<()>; }
+#[derive(Display)]
+struct S;
+
+impl Debug for S {
+    fn fmt(&self, f: &mut Formatter) -> Result<()> {
+        ${0:todo!()}
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_if_let_with_match() {
+    check_doc_test(
+        "replace_if_let_with_match",
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    $0if let Action::Move { distance } = action {
+        foo(distance)
+    } else {
+        bar()
+    }
+}
+"#####,
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move { distance } => foo(distance),
+        _ => bar(),
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_impl_trait_with_generic() {
+    check_doc_test(
+        "replace_impl_trait_with_generic",
+        r#####"
+fn foo(bar: $0impl Bar) {}
+"#####,
+        r#####"
+fn foo<B: Bar>(bar: B) {}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_let_with_if_let() {
+    check_doc_test(
+        "replace_let_with_if_let",
+        r#####"
+enum Option<T> { Some(T), None }
+
+fn main(action: Action) {
+    $0let x = compute();
+}
+
+fn compute() -> Option<i32> { None }
+"#####,
+        r#####"
+enum Option<T> { Some(T), None }
+
+fn main(action: Action) {
+    if let Some(x) = compute() {
+    }
+}
+
+fn compute() -> Option<i32> { None }
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_match_with_if_let() {
+    check_doc_test(
+        "replace_match_with_if_let",
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    $0match action {
+        Action::Move { distance } => foo(distance),
+        _ => bar(),
+    }
+}
+"#####,
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    if let Action::Move { distance } = action {
+        foo(distance)
+    } else {
+        bar()
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_qualified_name_with_use() {
+    check_doc_test(
+        "replace_qualified_name_with_use",
+        r#####"
+fn process(map: std::collections::$0HashMap<String, String>) {}
+"#####,
+        r#####"
+use std::collections::HashMap;
+
+fn process(map: HashMap<String, String>) {}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_string_with_char() {
+    check_doc_test(
+        "replace_string_with_char",
+        r#####"
+fn main() {
+    find("{$0");
+}
+"#####,
+        r#####"
+fn main() {
+    find('{');
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_unwrap_with_match() {
+    check_doc_test(
+        "replace_unwrap_with_match",
+        r#####"
+enum Result<T, E> { Ok(T), Err(E) }
+fn main() {
+    let x: Result<i32, i32> = Result::Ok(92);
+    let y = x.$0unwrap();
+}
+"#####,
+        r#####"
+enum Result<T, E> { Ok(T), Err(E) }
+fn main() {
+    let x: Result<i32, i32> = Result::Ok(92);
+    let y = match x {
+        Ok(a) => a,
+        $0_ => unreachable!(),
+    };
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_split_import() {
+    check_doc_test(
+        "split_import",
+        r#####"
+use std::$0collections::HashMap;
+"#####,
+        r#####"
+use std::{collections::HashMap};
+"#####,
+    )
+}
+
+#[test]
+fn doctest_toggle_ignore() {
+    check_doc_test(
+        "toggle_ignore",
+        r#####"
+$0#[test]
+fn arithmetics {
+    assert_eq!(2 + 2, 5);
+}
+"#####,
+        r#####"
+#[test]
+#[ignore]
+fn arithmetics {
+    assert_eq!(2 + 2, 5);
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_unmerge_use() {
+    check_doc_test(
+        "unmerge_use",
+        r#####"
+use std::fmt::{Debug, Display$0};
+"#####,
+        r#####"
+use std::fmt::{Debug};
+use std::fmt::Display;
+"#####,
+    )
+}
+
+#[test]
+fn doctest_unwrap_block() {
+    check_doc_test(
+        "unwrap_block",
+        r#####"
+fn foo() {
+    if true {$0
+        println!("foo");
+    }
+}
+"#####,
+        r#####"
+fn foo() {
+    println!("foo");
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_wrap_return_type_in_result() {
+    check_doc_test(
+        "wrap_return_type_in_result",
+        r#####"
+fn foo() -> i32$0 { 42i32 }
+"#####,
+        r#####"
+fn foo() -> Result<i32, ${0:_}> { Ok(42i32) }
+"#####,
+    )
+}
diff --git a/crates/ide_assists/src/utils.rs b/crates/ide_assists/src/utils.rs
new file mode 100644
index 000000000..0074da741
--- /dev/null
+++ b/crates/ide_assists/src/utils.rs
@@ -0,0 +1,434 @@
+//! Assorted functions shared by several assists.
+
+use std::ops;
+
+use ast::TypeBoundsOwner;
+use hir::{Adt, HasSource};
+use ide_db::{helpers::SnippetCap, RootDatabase};
+use itertools::Itertools;
+use stdx::format_to;
+use syntax::{
+    ast::edit::AstNodeEdit,
+    ast::AttrsOwner,
+    ast::NameOwner,
+    ast::{self, edit, make, ArgListOwner, GenericParamsOwner},
+    AstNode, Direction, SmolStr,
+    SyntaxKind::*,
+    SyntaxNode, TextSize, T,
+};
+
+use crate::{
+    assist_context::AssistContext,
+    ast_transform::{self, AstTransform, QualifyPaths, SubstituteTypeParams},
+};
+
+pub(crate) fn unwrap_trivial_block(block: ast::BlockExpr) -> ast::Expr {
+    extract_trivial_expression(&block)
+        .filter(|expr| !expr.syntax().text().contains_char('\n'))
+        .unwrap_or_else(|| block.into())
+}
+
+pub fn extract_trivial_expression(block: &ast::BlockExpr) -> Option<ast::Expr> {
+    let has_anything_else = |thing: &SyntaxNode| -> bool {
+        let mut non_trivial_children =
+            block.syntax().children_with_tokens().filter(|it| match it.kind() {
+                WHITESPACE | T!['{'] | T!['}'] => false,
+                _ => it.as_node() != Some(thing),
+            });
+        non_trivial_children.next().is_some()
+    };
+
+    if let Some(expr) = block.tail_expr() {
+        if has_anything_else(expr.syntax()) {
+            return None;
+        }
+        return Some(expr);
+    }
+    // Unwrap `{ continue; }`
+    let (stmt,) = block.statements().next_tuple()?;
+    if let ast::Stmt::ExprStmt(expr_stmt) = stmt {
+        if has_anything_else(expr_stmt.syntax()) {
+            return None;
+        }
+        let expr = expr_stmt.expr()?;
+        match expr.syntax().kind() {
+            CONTINUE_EXPR | BREAK_EXPR | RETURN_EXPR => return Some(expr),
+            _ => (),
+        }
+    }
+    None
+}
+
+/// This is a method with a heuristics to support test methods annotated with custom test annotations, such as
+/// `#[test_case(...)]`, `#[tokio::test]` and similar.
+/// Also a regular `#[test]` annotation is supported.
+///
+/// It may produce false positives, for example, `#[wasm_bindgen_test]` requires a different command to run the test,
+/// but it's better than not to have the runnables for the tests at all.
+pub fn test_related_attribute(fn_def: &ast::Fn) -> Option<ast::Attr> {
+    fn_def.attrs().find_map(|attr| {
+        let path = attr.path()?;
+        if path.syntax().text().to_string().contains("test") {
+            Some(attr)
+        } else {
+            None
+        }
+    })
+}
+
+#[derive(Copy, Clone, PartialEq)]
+pub enum DefaultMethods {
+    Only,
+    No,
+}
+
+pub fn filter_assoc_items(
+    db: &RootDatabase,
+    items: &[hir::AssocItem],
+    default_methods: DefaultMethods,
+) -> Vec<ast::AssocItem> {
+    fn has_def_name(item: &ast::AssocItem) -> bool {
+        match item {
+            ast::AssocItem::Fn(def) => def.name(),
+            ast::AssocItem::TypeAlias(def) => def.name(),
+            ast::AssocItem::Const(def) => def.name(),
+            ast::AssocItem::MacroCall(_) => None,
+        }
+        .is_some()
+    }
+
+    items
+        .iter()
+        // Note: This throws away items with no source.
+        .filter_map(|i| {
+            let item = match i {
+                hir::AssocItem::Function(i) => ast::AssocItem::Fn(i.source(db)?.value),
+                hir::AssocItem::TypeAlias(i) => ast::AssocItem::TypeAlias(i.source(db)?.value),
+                hir::AssocItem::Const(i) => ast::AssocItem::Const(i.source(db)?.value),
+            };
+            Some(item)
+        })
+        .filter(has_def_name)
+        .filter(|it| match it {
+            ast::AssocItem::Fn(def) => matches!(
+                (default_methods, def.body()),
+                (DefaultMethods::Only, Some(_)) | (DefaultMethods::No, None)
+            ),
+            _ => default_methods == DefaultMethods::No,
+        })
+        .collect::<Vec<_>>()
+}
+
+pub fn add_trait_assoc_items_to_impl(
+    sema: &hir::Semantics<ide_db::RootDatabase>,
+    items: Vec<ast::AssocItem>,
+    trait_: hir::Trait,
+    impl_def: ast::Impl,
+    target_scope: hir::SemanticsScope,
+) -> (ast::Impl, ast::AssocItem) {
+    let impl_item_list = impl_def.assoc_item_list().unwrap_or_else(make::assoc_item_list);
+
+    let n_existing_items = impl_item_list.assoc_items().count();
+    let source_scope = sema.scope_for_def(trait_);
+    let ast_transform = QualifyPaths::new(&target_scope, &source_scope)
+        .or(SubstituteTypeParams::for_trait_impl(&source_scope, trait_, impl_def.clone()));
+
+    let items = items
+        .into_iter()
+        .map(|it| ast_transform::apply(&*ast_transform, it))
+        .map(|it| match it {
+            ast::AssocItem::Fn(def) => ast::AssocItem::Fn(add_body(def)),
+            ast::AssocItem::TypeAlias(def) => ast::AssocItem::TypeAlias(def.remove_bounds()),
+            _ => it,
+        })
+        .map(|it| edit::remove_attrs_and_docs(&it));
+
+    let new_impl_item_list = impl_item_list.append_items(items);
+    let new_impl_def = impl_def.with_assoc_item_list(new_impl_item_list);
+    let first_new_item =
+        new_impl_def.assoc_item_list().unwrap().assoc_items().nth(n_existing_items).unwrap();
+    return (new_impl_def, first_new_item);
+
+    fn add_body(fn_def: ast::Fn) -> ast::Fn {
+        match fn_def.body() {
+            Some(_) => fn_def,
+            None => {
+                let body =
+                    make::block_expr(None, Some(make::expr_todo())).indent(edit::IndentLevel(1));
+                fn_def.with_body(body)
+            }
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+pub(crate) enum Cursor<'a> {
+    Replace(&'a SyntaxNode),
+    Before(&'a SyntaxNode),
+}
+
+impl<'a> Cursor<'a> {
+    fn node(self) -> &'a SyntaxNode {
+        match self {
+            Cursor::Replace(node) | Cursor::Before(node) => node,
+        }
+    }
+}
+
+pub(crate) fn render_snippet(_cap: SnippetCap, node: &SyntaxNode, cursor: Cursor) -> String {
+    assert!(cursor.node().ancestors().any(|it| it == *node));
+    let range = cursor.node().text_range() - node.text_range().start();
+    let range: ops::Range<usize> = range.into();
+
+    let mut placeholder = cursor.node().to_string();
+    escape(&mut placeholder);
+    let tab_stop = match cursor {
+        Cursor::Replace(placeholder) => format!("${{0:{}}}", placeholder),
+        Cursor::Before(placeholder) => format!("$0{}", placeholder),
+    };
+
+    let mut buf = node.to_string();
+    buf.replace_range(range, &tab_stop);
+    return buf;
+
+    fn escape(buf: &mut String) {
+        stdx::replace(buf, '{', r"\{");
+        stdx::replace(buf, '}', r"\}");
+        stdx::replace(buf, '$', r"\$");
+    }
+}
+
+pub(crate) fn vis_offset(node: &SyntaxNode) -> TextSize {
+    node.children_with_tokens()
+        .find(|it| !matches!(it.kind(), WHITESPACE | COMMENT | ATTR))
+        .map(|it| it.text_range().start())
+        .unwrap_or_else(|| node.text_range().start())
+}
+
+pub(crate) fn invert_boolean_expression(expr: ast::Expr) -> ast::Expr {
+    if let Some(expr) = invert_special_case(&expr) {
+        return expr;
+    }
+    make::expr_prefix(T![!], expr)
+}
+
+fn invert_special_case(expr: &ast::Expr) -> Option<ast::Expr> {
+    match expr {
+        ast::Expr::BinExpr(bin) => match bin.op_kind()? {
+            ast::BinOp::NegatedEqualityTest => bin.replace_op(T![==]).map(|it| it.into()),
+            ast::BinOp::EqualityTest => bin.replace_op(T![!=]).map(|it| it.into()),
+            // Parenthesize composite boolean expressions before prefixing `!`
+            ast::BinOp::BooleanAnd | ast::BinOp::BooleanOr => {
+                Some(make::expr_prefix(T![!], make::expr_paren(expr.clone())))
+            }
+            _ => None,
+        },
+        ast::Expr::MethodCallExpr(mce) => {
+            let receiver = mce.receiver()?;
+            let method = mce.name_ref()?;
+            let arg_list = mce.arg_list()?;
+
+            let method = match method.text() {
+                "is_some" => "is_none",
+                "is_none" => "is_some",
+                "is_ok" => "is_err",
+                "is_err" => "is_ok",
+                _ => return None,
+            };
+            Some(make::expr_method_call(receiver, method, arg_list))
+        }
+        ast::Expr::PrefixExpr(pe) if pe.op_kind()? == ast::PrefixOp::Not => {
+            if let ast::Expr::ParenExpr(parexpr) = pe.expr()? {
+                parexpr.expr()
+            } else {
+                pe.expr()
+            }
+        }
+        // FIXME:
+        // ast::Expr::Literal(true | false )
+        _ => None,
+    }
+}
+
+pub(crate) fn next_prev() -> impl Iterator<Item = Direction> {
+    [Direction::Next, Direction::Prev].iter().copied()
+}
+
+pub(crate) fn does_pat_match_variant(pat: &ast::Pat, var: &ast::Pat) -> bool {
+    let first_node_text = |pat: &ast::Pat| pat.syntax().first_child().map(|node| node.text());
+
+    let pat_head = match pat {
+        ast::Pat::IdentPat(bind_pat) => {
+            if let Some(p) = bind_pat.pat() {
+                first_node_text(&p)
+            } else {
+                return pat.syntax().text() == var.syntax().text();
+            }
+        }
+        pat => first_node_text(pat),
+    };
+
+    let var_head = first_node_text(var);
+
+    pat_head == var_head
+}
+
+// Uses a syntax-driven approach to find any impl blocks for the struct that
+// exist within the module/file
+//
+// Returns `None` if we've found an existing fn
+//
+// FIXME: change the new fn checking to a more semantic approach when that's more
+// viable (e.g. we process proc macros, etc)
+// FIXME: this partially overlaps with `find_impl_block_*`
+pub(crate) fn find_struct_impl(
+    ctx: &AssistContext,
+    strukt: &ast::Adt,
+    name: &str,
+) -> Option<Option<ast::Impl>> {
+    let db = ctx.db();
+    let module = strukt.syntax().ancestors().find(|node| {
+        ast::Module::can_cast(node.kind()) || ast::SourceFile::can_cast(node.kind())
+    })?;
+
+    let struct_def = match strukt {
+        ast::Adt::Enum(e) => Adt::Enum(ctx.sema.to_def(e)?),
+        ast::Adt::Struct(s) => Adt::Struct(ctx.sema.to_def(s)?),
+        ast::Adt::Union(u) => Adt::Union(ctx.sema.to_def(u)?),
+    };
+
+    let block = module.descendants().filter_map(ast::Impl::cast).find_map(|impl_blk| {
+        let blk = ctx.sema.to_def(&impl_blk)?;
+
+        // FIXME: handle e.g. `struct S<T>; impl<U> S<U> {}`
+        // (we currently use the wrong type parameter)
+        // also we wouldn't want to use e.g. `impl S<u32>`
+
+        let same_ty = match blk.target_ty(db).as_adt() {
+            Some(def) => def == struct_def,
+            None => false,
+        };
+        let not_trait_impl = blk.target_trait(db).is_none();
+
+        if !(same_ty && not_trait_impl) {
+            None
+        } else {
+            Some(impl_blk)
+        }
+    });
+
+    if let Some(ref impl_blk) = block {
+        if has_fn(impl_blk, name) {
+            return None;
+        }
+    }
+
+    Some(block)
+}
+
+fn has_fn(imp: &ast::Impl, rhs_name: &str) -> bool {
+    if let Some(il) = imp.assoc_item_list() {
+        for item in il.assoc_items() {
+            if let ast::AssocItem::Fn(f) = item {
+                if let Some(name) = f.name() {
+                    if name.text().eq_ignore_ascii_case(rhs_name) {
+                        return true;
+                    }
+                }
+            }
+        }
+    }
+
+    false
+}
+
+/// Find the start of the `impl` block for the given `ast::Impl`.
+//
+// FIXME: this partially overlaps with `find_struct_impl`
+pub(crate) fn find_impl_block_start(impl_def: ast::Impl, buf: &mut String) -> Option<TextSize> {
+    buf.push('\n');
+    let start = impl_def.assoc_item_list().and_then(|it| it.l_curly_token())?.text_range().end();
+    Some(start)
+}
+
+/// Find the end of the `impl` block for the given `ast::Impl`.
+//
+// FIXME: this partially overlaps with `find_struct_impl`
+pub(crate) fn find_impl_block_end(impl_def: ast::Impl, buf: &mut String) -> Option<TextSize> {
+    buf.push('\n');
+    let end = impl_def
+        .assoc_item_list()
+        .and_then(|it| it.r_curly_token())?
+        .prev_sibling_or_token()?
+        .text_range()
+        .end();
+    Some(end)
+}
+
+// Generates the surrounding `impl Type { <code> }` including type and lifetime
+// parameters
+pub(crate) fn generate_impl_text(adt: &ast::Adt, code: &str) -> String {
+    generate_impl_text_inner(adt, None, code)
+}
+
+// Generates the surrounding `impl <trait> for Type { <code> }` including type
+// and lifetime parameters
+pub(crate) fn generate_trait_impl_text(adt: &ast::Adt, trait_text: &str, code: &str) -> String {
+    generate_impl_text_inner(adt, Some(trait_text), code)
+}
+
+fn generate_impl_text_inner(adt: &ast::Adt, trait_text: Option<&str>, code: &str) -> String {
+    let generic_params = adt.generic_param_list();
+    let mut buf = String::with_capacity(code.len());
+    buf.push_str("\n\n");
+    adt.attrs()
+        .filter(|attr| attr.as_simple_call().map(|(name, _arg)| name == "cfg").unwrap_or(false))
+        .for_each(|attr| buf.push_str(format!("{}\n", attr.to_string()).as_str()));
+    buf.push_str("impl");
+    if let Some(generic_params) = &generic_params {
+        let lifetimes = generic_params.lifetime_params().map(|lt| format!("{}", lt.syntax()));
+        let type_params = generic_params.type_params().map(|type_param| {
+            let mut buf = String::new();
+            if let Some(it) = type_param.name() {
+                format_to!(buf, "{}", it.syntax());
+            }
+            if let Some(it) = type_param.colon_token() {
+                format_to!(buf, "{} ", it);
+            }
+            if let Some(it) = type_param.type_bound_list() {
+                format_to!(buf, "{}", it.syntax());
+            }
+            buf
+        });
+        let generics = lifetimes.chain(type_params).format(", ");
+        format_to!(buf, "<{}>", generics);
+    }
+    buf.push(' ');
+    if let Some(trait_text) = trait_text {
+        buf.push_str(trait_text);
+        buf.push_str(" for ");
+    }
+    buf.push_str(adt.name().unwrap().text());
+    if let Some(generic_params) = generic_params {
+        let lifetime_params = generic_params
+            .lifetime_params()
+            .filter_map(|it| it.lifetime())
+            .map(|it| SmolStr::from(it.text()));
+        let type_params = generic_params
+            .type_params()
+            .filter_map(|it| it.name())
+            .map(|it| SmolStr::from(it.text()));
+        format_to!(buf, "<{}>", lifetime_params.chain(type_params).format(", "))
+    }
+
+    match adt.where_clause() {
+        Some(where_clause) => {
+            format_to!(buf, "\n{}\n{{\n{}\n}}", where_clause, code);
+        }
+        None => {
+            format_to!(buf, " {{\n{}\n}}", code);
+        }
+    }
+
+    buf
+}