131 files changed, 4029 insertions, 3364 deletions

diff --git a/crates/ra_assists/src/assist_config.rs b/crates/ra_assists/src/assist_config.rs
new file mode 100644
index 000000000..c0a0226fb
--- /dev/null
+++ b/crates/ra_assists/src/assist_config.rs
@@ -0,0 +1,27 @@
+//! 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.
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct AssistConfig {
+    pub snippet_cap: Option<SnippetCap>,
+}
+
+impl AssistConfig {
+    pub fn allow_snippets(&mut self, yes: bool) {
+        self.snippet_cap = if yes { Some(SnippetCap { _private: () }) } else { None }
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct SnippetCap {
+    _private: (),
+}
+
+impl Default for AssistConfig {
+    fn default() -> Self {
+        AssistConfig { snippet_cap: Some(SnippetCap { _private: () }) }
+    }
+}
diff --git a/crates/ra_assists/src/assist_context.rs b/crates/ra_assists/src/assist_context.rs
index a680f752b..5b1a4680b 100644
--- a/crates/ra_assists/src/assist_context.rs
+++ b/crates/ra_assists/src/assist_context.rs
@@ -5,7 +5,7 @@ use hir::Semantics;
 use ra_db::{FileId, FileRange};
 use ra_fmt::{leading_indent, reindent};
 use ra_ide_db::{
-    source_change::{SingleFileChange, SourceChange},
+    source_change::{SourceChange, SourceFileEdit},
     RootDatabase,
 };
 use ra_syntax::{
@@ -15,7 +15,10 @@ use ra_syntax::{
 };
 use ra_text_edit::TextEditBuilder;
 
-use crate::{Assist, AssistId, GroupLabel, ResolvedAssist};
+use crate::{
+    assist_config::{AssistConfig, SnippetCap},
+    Assist, AssistId, GroupLabel, ResolvedAssist,
+};
 
 /// `AssistContext` allows to apply an assist or check if it could be applied.
 ///
@@ -48,6 +51,7 @@ use crate::{Assist, AssistId, GroupLabel, ResolvedAssist};
 /// 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) db: &'a RootDatabase,
     pub(crate) frange: FileRange,
@@ -55,10 +59,14 @@ pub(crate) struct AssistContext<'a> {
 }
 
 impl<'a> AssistContext<'a> {
-    pub fn new(sema: Semantics<'a, RootDatabase>, frange: FileRange) -> 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);
         let db = sema.db;
-        AssistContext { sema, db, frange, source_file }
+        AssistContext { config, sema, db, frange, source_file }
     }
 
     // NB, this ignores active selection.
@@ -142,11 +150,10 @@ impl Assists {
         self.add_impl(label, f)
     }
     fn add_impl(&mut self, label: Assist, f: impl FnOnce(&mut AssistBuilder)) -> Option<()> {
-        let change_label = label.label.clone();
         let source_change = if self.resolve {
             let mut builder = AssistBuilder::new(self.file);
             f(&mut builder);
-            Some(builder.finish(change_label))
+            Some(builder.finish())
         } else {
             None
         };
@@ -163,13 +170,13 @@ impl Assists {
 
 pub(crate) struct AssistBuilder {
     edit: TextEditBuilder,
-    cursor_position: Option<TextSize>,
     file: FileId,
+    is_snippet: bool,
 }
 
 impl AssistBuilder {
     pub(crate) fn new(file: FileId) -> AssistBuilder {
-        AssistBuilder { edit: TextEditBuilder::default(), cursor_position: None, file }
+        AssistBuilder { edit: TextEditBuilder::default(), file, is_snippet: false }
     }
 
     /// Remove specified `range` of text.
@@ -180,10 +187,30 @@ impl AssistBuilder {
     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.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.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)
     }
@@ -207,10 +234,6 @@ impl AssistBuilder {
         algo::diff(&node, &new).into_text_edit(&mut self.edit)
     }
 
-    /// Specify desired position of the cursor after the assist is applied.
-    pub(crate) fn set_cursor(&mut self, offset: TextSize) {
-        self.cursor_position = Some(offset)
-    }
     // FIXME: better API
     pub(crate) fn set_file(&mut self, assist_file: FileId) {
         self.file = assist_file;
@@ -222,12 +245,13 @@ impl AssistBuilder {
         &mut self.edit
     }
 
-    fn finish(self, change_label: String) -> SourceChange {
+    fn finish(self) -> SourceChange {
         let edit = self.edit.finish();
-        if edit.is_empty() && self.cursor_position.is_none() {
-            panic!("Only call `add_assist` if the assist can be applied")
+        let source_file_edit = SourceFileEdit { file_id: self.file, edit };
+        let mut res: SourceChange = source_file_edit.into();
+        if self.is_snippet {
+            res.is_snippet = true;
         }
-        SingleFileChange { label: change_label, edit, cursor_position: self.cursor_position }
-            .into_source_change(self.file)
+        res
     }
 }
diff --git a/crates/ra_assists/src/handlers/add_custom_impl.rs b/crates/ra_assists/src/handlers/add_custom_impl.rs
index 2baeb8607..fa70c8496 100644
--- a/crates/ra_assists/src/handlers/add_custom_impl.rs
+++ b/crates/ra_assists/src/handlers/add_custom_impl.rs
@@ -25,7 +25,7 @@ use crate::{
 // struct S;
 //
 // impl Debug for S {
-//
+//     $0
 // }
 // ```
 pub(crate) fn add_custom_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
@@ -52,7 +52,7 @@ pub(crate) fn add_custom_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<
         format!("Add custom impl `{}` for `{}`", trait_token.text().as_str(), annotated_name);
 
     let target = attr.syntax().text_range();
-    acc.add(AssistId("add_custom_impl"), label, target, |edit| {
+    acc.add(AssistId("add_custom_impl"), label, target, |builder| {
         let new_attr_input = input
             .syntax()
             .descendants_with_tokens()
@@ -63,20 +63,11 @@ pub(crate) fn add_custom_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<
         let has_more_derives = !new_attr_input.is_empty();
         let new_attr_input = new_attr_input.iter().sep_by(", ").surround_with("(", ")").to_string();
 
-        let mut buf = String::new();
-        buf.push_str("\n\nimpl ");
-        buf.push_str(trait_token.text().as_str());
-        buf.push_str(" for ");
-        buf.push_str(annotated_name.as_str());
-        buf.push_str(" {\n");
-
-        let cursor_delta = if has_more_derives {
-            let delta = input.syntax().text_range().len() - TextSize::of(&new_attr_input);
-            edit.replace(input.syntax().text_range(), new_attr_input);
-            delta
+        if has_more_derives {
+            builder.replace(input.syntax().text_range(), new_attr_input);
         } else {
             let attr_range = attr.syntax().text_range();
-            edit.delete(attr_range);
+            builder.delete(attr_range);
 
             let line_break_range = attr
                 .syntax()
@@ -84,14 +75,24 @@ pub(crate) fn add_custom_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<
                 .filter(|t| t.kind() == WHITESPACE)
                 .map(|t| t.text_range())
                 .unwrap_or_else(|| TextRange::new(TextSize::from(0), TextSize::from(0)));
-            edit.delete(line_break_range);
-
-            attr_range.len() + line_break_range.len()
-        };
-
-        edit.set_cursor(start_offset + TextSize::of(&buf) - cursor_delta);
-        buf.push_str("\n}");
-        edit.insert(start_offset, buf);
+            builder.delete(line_break_range);
+        }
+
+        match ctx.config.snippet_cap {
+            Some(cap) => {
+                builder.insert_snippet(
+                    cap,
+                    start_offset,
+                    format!("\n\nimpl {} for {} {{\n    $0\n}}", trait_token, annotated_name),
+                );
+            }
+            None => {
+                builder.insert(
+                    start_offset,
+                    format!("\n\nimpl {} for {} {{\n\n}}", trait_token, annotated_name),
+                );
+            }
+        }
     })
 }
 
@@ -117,7 +118,7 @@ struct Foo {
 }
 
 impl Debug for Foo {
-<|>
+    $0
 }
             ",
         )
@@ -139,7 +140,7 @@ pub struct Foo {
 }
 
 impl Debug for Foo {
-<|>
+    $0
 }
             ",
         )
@@ -158,7 +159,7 @@ struct Foo {}
 struct Foo {}
 
 impl Debug for Foo {
-<|>
+    $0
 }
             ",
         )
diff --git a/crates/ra_assists/src/handlers/add_derive.rs b/crates/ra_assists/src/handlers/add_derive.rs
index fb08c19e9..b123b8498 100644
--- a/crates/ra_assists/src/handlers/add_derive.rs
+++ b/crates/ra_assists/src/handlers/add_derive.rs
@@ -18,31 +18,37 @@ use crate::{AssistContext, AssistId, Assists};
 // ```
 // ->
 // ```
-// #[derive()]
+// #[derive($0)]
 // struct Point {
 //     x: u32,
 //     y: u32,
 // }
 // ```
 pub(crate) fn add_derive(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let cap = ctx.config.snippet_cap?;
     let nominal = ctx.find_node_at_offset::<ast::NominalDef>()?;
     let node_start = derive_insertion_offset(&nominal)?;
     let target = nominal.syntax().text_range();
-    acc.add(AssistId("add_derive"), "Add `#[derive]`", target, |edit| {
+    acc.add(AssistId("add_derive"), "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();
-        let offset = match derive_attr {
+        match derive_attr {
             None => {
-                edit.insert(node_start, "#[derive()]\n");
-                node_start + TextSize::of("#[derive(")
+                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",
+                )
             }
-            Some(tt) => tt.syntax().text_range().end() - TextSize::of(')'),
         };
-        edit.set_cursor(offset)
     })
 }
 
@@ -66,12 +72,12 @@ mod tests {
         check_assist(
             add_derive,
             "struct Foo { a: i32, <|>}",
-            "#[derive(<|>)]\nstruct Foo { a: i32, }",
+            "#[derive($0)]\nstruct Foo { a: i32, }",
         );
         check_assist(
             add_derive,
             "struct Foo { <|> a: i32, }",
-            "#[derive(<|>)]\nstruct Foo {  a: i32, }",
+            "#[derive($0)]\nstruct Foo {  a: i32, }",
         );
     }
 
@@ -80,7 +86,7 @@ mod tests {
         check_assist(
             add_derive,
             "#[derive(Clone)]\nstruct Foo { a: i32<|>, }",
-            "#[derive(Clone<|>)]\nstruct Foo { a: i32, }",
+            "#[derive(Clone$0)]\nstruct Foo { a: i32, }",
         );
     }
 
@@ -96,7 +102,7 @@ struct Foo { a: i32<|>, }
             "
 /// `Foo` is a pretty important struct.
 /// It does stuff.
-#[derive(<|>)]
+#[derive($0)]
 struct Foo { a: i32, }
             ",
         );
diff --git a/crates/ra_assists/src/handlers/add_explicit_type.rs b/crates/ra_assists/src/handlers/add_explicit_type.rs
index 0c7d5e355..ab20c6649 100644
--- a/crates/ra_assists/src/handlers/add_explicit_type.rs
+++ b/crates/ra_assists/src/handlers/add_explicit_type.rs
@@ -25,9 +25,8 @@ pub(crate) fn add_explicit_type(acc: &mut Assists, ctx: &AssistContext) -> Optio
     let stmt = ctx.find_node_at_offset::<LetStmt>()?;
     let module = ctx.sema.scope(stmt.syntax()).module()?;
     let expr = stmt.initializer()?;
-    let pat = stmt.pat()?;
     // Must be a binding
-    let pat = match pat {
+    let pat = match stmt.pat()? {
         ast::Pat::BindPat(bind_pat) => bind_pat,
         _ => return None,
     };
@@ -46,7 +45,7 @@ pub(crate) fn add_explicit_type(acc: &mut Assists, ctx: &AssistContext) -> Optio
     // Assist not applicable if the type has already been specified
     // and it has no placeholders
     let ascribed_ty = stmt.ascribed_type();
-    if let Some(ref ty) = ascribed_ty {
+    if let Some(ty) = &ascribed_ty {
         if ty.syntax().descendants().find_map(ast::PlaceholderType::cast).is_none() {
             return None;
         }
@@ -87,11 +86,7 @@ mod tests {
 
     #[test]
     fn add_explicit_type_works_for_simple_expr() {
-        check_assist(
-            add_explicit_type,
-            "fn f() { let a<|> = 1; }",
-            "fn f() { let a<|>: i32 = 1; }",
-        );
+        check_assist(add_explicit_type, "fn f() { let a<|> = 1; }", "fn f() { let a: i32 = 1; }");
     }
 
     #[test]
@@ -99,7 +94,7 @@ mod tests {
         check_assist(
             add_explicit_type,
             "fn f() { let a<|>: _ = 1; }",
-            "fn f() { let a<|>: i32 = 1; }",
+            "fn f() { let a: i32 = 1; }",
         );
     }
 
@@ -123,7 +118,7 @@ mod tests {
             }
 
             fn f() {
-                let a<|>: Option<i32> = Option::Some(1);
+                let a: Option<i32> = Option::Some(1);
             }"#,
         );
     }
@@ -133,7 +128,7 @@ mod tests {
         check_assist(
             add_explicit_type,
             r"macro_rules! v { () => {0u64} } fn f() { let a<|> = v!(); }",
-            r"macro_rules! v { () => {0u64} } fn f() { let a<|>: u64 = v!(); }",
+            r"macro_rules! v { () => {0u64} } fn f() { let a: u64 = v!(); }",
         );
     }
 
@@ -141,8 +136,8 @@ mod tests {
     fn add_explicit_type_works_for_macro_call_recursive() {
         check_assist(
             add_explicit_type,
-            "macro_rules! u { () => {0u64} } macro_rules! v { () => {u!()} } fn f() { let a<|> = v!(); }",
-            "macro_rules! u { () => {0u64} } macro_rules! v { () => {u!()} } fn f() { let a<|>: u64 = v!(); }",
+            r#"macro_rules! u { () => {0u64} } macro_rules! v { () => {u!()} } fn f() { let a<|> = v!(); }"#,
+            r#"macro_rules! u { () => {0u64} } macro_rules! v { () => {u!()} } fn f() { let a: u64 = v!(); }"#,
         );
     }
 
@@ -209,7 +204,7 @@ struct Test<K, T = u8> {
 }
 
 fn main() {
-    let test<|>: Test<i32> = Test { t: 23, k: 33 };
+    let test: Test<i32> = Test { t: 23, k: 33 };
 }"#,
         );
     }
diff --git a/crates/ra_assists/src/handlers/add_from_impl_for_enum.rs b/crates/ra_assists/src/handlers/add_from_impl_for_enum.rs
index 6a49b7dbd..6a675e812 100644
--- a/crates/ra_assists/src/handlers/add_from_impl_for_enum.rs
+++ b/crates/ra_assists/src/handlers/add_from_impl_for_enum.rs
@@ -1,7 +1,6 @@
 use ra_ide_db::RootDatabase;
 use ra_syntax::ast::{self, AstNode, NameOwner};
-use stdx::format_to;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{utils::FamousDefs, AssistContext, AssistId, Assists};
 
@@ -35,12 +34,12 @@ pub(crate) fn add_from_impl_for_enum(acc: &mut Assists, ctx: &AssistContext) ->
     }
     let field_type = field_list.fields().next()?.type_ref()?;
     let path = match field_type {
-        ast::TypeRef::PathType(p) => p,
+        ast::TypeRef::PathType(it) => it,
         _ => return None,
     };
 
     if existing_from_impl(&ctx.sema, &variant).is_some() {
-        tested_by!(test_add_from_impl_already_exists);
+        mark::hit!(test_add_from_impl_already_exists);
         return None;
     }
 
@@ -51,9 +50,7 @@ pub(crate) fn add_from_impl_for_enum(acc: &mut Assists, ctx: &AssistContext) ->
         target,
         |edit| {
             let start_offset = variant.parent_enum().syntax().text_range().end();
-            let mut buf = String::new();
-            format_to!(
-                buf,
+            let buf = format!(
                 r#"
 
 impl From<{0}> for {1} {{
@@ -93,7 +90,7 @@ fn existing_from_impl(
 
 #[cfg(test)]
 mod tests {
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::tests::{check_assist, check_assist_not_applicable};
 
@@ -104,7 +101,7 @@ mod tests {
         check_assist(
             add_from_impl_for_enum,
             "enum A { <|>One(u32) }",
-            r#"enum A { <|>One(u32) }
+            r#"enum A { One(u32) }
 
 impl From<u32> for A {
     fn from(v: u32) -> Self {
@@ -119,7 +116,7 @@ impl From<u32> for A {
         check_assist(
             add_from_impl_for_enum,
             r#"enum A { <|>One(foo::bar::baz::Boo) }"#,
-            r#"enum A { <|>One(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 {
@@ -152,7 +149,7 @@ impl From<foo::bar::baz::Boo> for A {
 
     #[test]
     fn test_add_from_impl_already_exists() {
-        covers!(test_add_from_impl_already_exists);
+        mark::check!(test_add_from_impl_already_exists);
         check_not_applicable(
             r#"
 enum A { <|>One(u32), }
@@ -181,7 +178,7 @@ impl From<String> for A {
 pub trait From<T> {
     fn from(T) -> Self;
 }"#,
-            r#"enum A { <|>One(u32), Two(String), }
+            r#"enum A { One(u32), Two(String), }
 
 impl From<u32> for A {
     fn from(v: u32) -> Self {
diff --git a/crates/ra_assists/src/handlers/add_function.rs b/crates/ra_assists/src/handlers/add_function.rs
index de016ae4e..24f931a85 100644
--- a/crates/ra_assists/src/handlers/add_function.rs
+++ b/crates/ra_assists/src/handlers/add_function.rs
@@ -4,13 +4,17 @@ use ra_syntax::{
     ast::{
         self,
         edit::{AstNodeEdit, IndentLevel},
-        ArgListOwner, AstNode, ModuleItemOwner,
+        make, ArgListOwner, AstNode, ModuleItemOwner,
     },
     SyntaxKind, SyntaxNode, TextSize,
 };
 use rustc_hash::{FxHashMap, FxHashSet};
 
-use crate::{AssistContext, AssistId, Assists};
+use crate::{
+    assist_config::SnippetCap,
+    utils::{render_snippet, Cursor},
+    AssistContext, AssistId, Assists,
+};
 
 // Assist: add_function
 //
@@ -33,7 +37,7 @@ use crate::{AssistContext, AssistId, Assists};
 // }
 //
 // fn bar(arg: &str, baz: Baz) {
-//     todo!()
+//     ${0:todo!()}
 // }
 //
 // ```
@@ -58,21 +62,40 @@ pub(crate) fn add_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
     let function_builder = FunctionBuilder::from_call(&ctx, &call, &path, target_module)?;
 
     let target = call.syntax().text_range();
-    acc.add(AssistId("add_function"), "Add function", target, |edit| {
+    acc.add(AssistId("add_function"), "Add function", target, |builder| {
         let function_template = function_builder.render();
-        edit.set_file(function_template.file);
-        edit.set_cursor(function_template.cursor_offset);
-        edit.insert(function_template.insert_offset, function_template.fn_def.to_string());
+        builder.set_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,
-    cursor_offset: TextSize,
-    fn_def: ast::SourceFile,
+    placeholder_expr: ast::MacroCall,
+    leading_ws: String,
+    fn_def: ast::FnDef,
+    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.placeholder_expr.syntax()),
+            ),
+            None => self.fn_def.to_string(),
+        };
+        format!("{}{}{}", self.leading_ws, f, self.trailing_ws)
+    }
+}
+
 struct FunctionBuilder {
     target: GeneratedFunctionTarget,
     fn_name: ast::Name,
@@ -110,35 +133,41 @@ impl FunctionBuilder {
     }
 
     fn render(self) -> FunctionTemplate {
-        let placeholder_expr = ast::make::expr_todo();
-        let fn_body = ast::make::block_expr(vec![], Some(placeholder_expr));
-        let mut fn_def = ast::make::fn_def(self.fn_name, self.type_params, self.params, fn_body);
-        if self.needs_pub {
-            fn_def = ast::make::add_pub_crate_modifier(fn_def);
-        }
-
-        let (fn_def, insert_offset) = match self.target {
+        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_def(visibility, self.fn_name, self.type_params, self.params, fn_body);
+        let leading_ws;
+        let trailing_ws;
+
+        let insert_offset = match self.target {
             GeneratedFunctionTarget::BehindItem(it) => {
-                let with_leading_blank_line = ast::make::add_leading_newlines(2, fn_def);
-                let indented = with_leading_blank_line.indent(IndentLevel::from_node(&it));
-                (indented, it.text_range().end())
+                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_once = IndentLevel(1);
                 let indent = IndentLevel::from_node(it.syntax());
-                let fn_def = ast::make::add_leading_newlines(1, fn_def);
-                let fn_def = fn_def.indent(indent_once);
-                let fn_def = ast::make::add_trailing_newlines(1, fn_def);
-                let fn_def = fn_def.indent(indent);
-                (fn_def, it.syntax().text_range().start() + TextSize::of('{'))
+                leading_ws = format!("\n{}", indent + 1);
+                fn_def = fn_def.indent(indent + 1);
+                trailing_ws = format!("\n{}", indent);
+                it.syntax().text_range().start() + TextSize::of('{')
             }
         };
 
         let placeholder_expr =
             fn_def.syntax().descendants().find_map(ast::MacroCall::cast).unwrap();
-        let cursor_offset_from_fn_start = placeholder_expr.syntax().text_range().start();
-        let cursor_offset = insert_offset + cursor_offset_from_fn_start;
-        FunctionTemplate { insert_offset, cursor_offset, fn_def, file: self.file }
+        FunctionTemplate {
+            insert_offset,
+            placeholder_expr,
+            leading_ws,
+            fn_def,
+            trailing_ws,
+            file: self.file,
+        }
     }
 }
 
@@ -158,7 +187,7 @@ impl GeneratedFunctionTarget {
 
 fn fn_name(call: &ast::Path) -> Option<ast::Name> {
     let name = call.segment()?.syntax().to_string();
-    Some(ast::make::name(&name))
+    Some(make::name(&name))
 }
 
 /// Computes the type variables and arguments required for the generated function
@@ -180,8 +209,8 @@ fn fn_args(
         });
     }
     deduplicate_arg_names(&mut arg_names);
-    let params = arg_names.into_iter().zip(arg_types).map(|(name, ty)| ast::make::param(name, ty));
-    Some((None, ast::make::param_list(params)))
+    let params = arg_names.into_iter().zip(arg_types).map(|(name, ty)| make::param(name, ty));
+    Some((None, make::param_list(params)))
 }
 
 /// Makes duplicate argument names unique by appending incrementing numbers.
@@ -316,7 +345,7 @@ fn foo() {
 }
 
 fn bar() {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -343,7 +372,7 @@ impl Foo {
 }
 
 fn bar() {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -367,7 +396,7 @@ fn foo1() {
 }
 
 fn bar() {
-    <|>todo!()
+    ${0:todo!()}
 }
 
 fn foo2() {}
@@ -393,7 +422,7 @@ mod baz {
     }
 
     fn bar() {
-        <|>todo!()
+        ${0:todo!()}
     }
 }
 ",
@@ -419,7 +448,7 @@ fn foo() {
 }
 
 fn bar(baz: Baz) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         );
@@ -452,7 +481,7 @@ impl Baz {
 }
 
 fn bar(baz: Baz) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -473,7 +502,7 @@ fn foo() {
 }
 
 fn bar(arg: &str) {
-    <|>todo!()
+    ${0:todo!()}
 }
 "#,
         )
@@ -494,7 +523,7 @@ fn foo() {
 }
 
 fn bar(arg: char) {
-    <|>todo!()
+    ${0:todo!()}
 }
 "#,
         )
@@ -515,7 +544,7 @@ fn foo() {
 }
 
 fn bar(arg: i32) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -536,7 +565,7 @@ fn foo() {
 }
 
 fn bar(arg: u8) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -561,7 +590,7 @@ fn foo() {
 }
 
 fn bar(x: u8) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -584,7 +613,7 @@ fn foo() {
 }
 
 fn bar(worble: ()) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -613,7 +642,7 @@ fn baz() {
 }
 
 fn bar(foo: impl Foo) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -640,7 +669,7 @@ fn foo() {
 }
 
 fn bar(baz: &Baz) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -669,7 +698,7 @@ fn foo() {
 }
 
 fn bar(baz: Baz::Bof) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -692,7 +721,7 @@ fn foo<T>(t: T) {
 }
 
 fn bar<T>(t: T) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -723,7 +752,7 @@ fn foo() {
 }
 
 fn bar(arg: fn() -> Baz) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -748,7 +777,7 @@ fn foo() {
 }
 
 fn bar(closure: impl Fn(i64) -> i64) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -769,7 +798,7 @@ fn foo() {
 }
 
 fn bar(baz: ()) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -794,7 +823,7 @@ fn foo() {
 }
 
 fn bar(baz_1: Baz, baz_2: Baz) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -819,7 +848,7 @@ fn foo() {
 }
 
 fn bar(baz_1: Baz, baz_2: Baz, arg_1: &str, arg_2: &str) {
-    <|>todo!()
+    ${0:todo!()}
 }
 "#,
         )
@@ -839,7 +868,7 @@ fn foo() {
             r"
 mod bar {
     pub(crate) fn my_fn() {
-        <|>todo!()
+        ${0:todo!()}
     }
 }
 
@@ -878,7 +907,7 @@ fn bar() {
 }
 
 fn baz(foo: foo::Foo) {
-    <|>todo!()
+    ${0:todo!()}
 }
 ",
         )
@@ -902,7 +931,7 @@ mod bar {
     fn something_else() {}
 
     pub(crate) fn my_fn() {
-        <|>todo!()
+        ${0:todo!()}
     }
 }
 
@@ -930,7 +959,7 @@ fn foo() {
 mod bar {
     mod baz {
         pub(crate) fn my_fn() {
-            <|>todo!()
+            ${0:todo!()}
         }
     }
 }
@@ -959,7 +988,7 @@ fn main() {
 
 
 pub(crate) fn bar() {
-    <|>todo!()
+    ${0:todo!()}
 }",
         )
     }
diff --git a/crates/ra_assists/src/handlers/add_impl.rs b/crates/ra_assists/src/handlers/add_impl.rs
index df114a0d8..eceba7d0a 100644
--- a/crates/ra_assists/src/handlers/add_impl.rs
+++ b/crates/ra_assists/src/handlers/add_impl.rs
@@ -1,7 +1,4 @@
-use ra_syntax::{
-    ast::{self, AstNode, NameOwner, TypeParamsOwner},
-    TextSize,
-};
+use ra_syntax::ast::{self, AstNode, NameOwner, TypeParamsOwner};
 use stdx::{format_to, SepBy};
 
 use crate::{AssistContext, AssistId, Assists};
@@ -12,17 +9,17 @@ use crate::{AssistContext, AssistId, Assists};
 //
 // ```
 // struct Ctx<T: Clone> {
-//      data: T,<|>
+//     data: T,<|>
 // }
 // ```
 // ->
 // ```
 // struct Ctx<T: Clone> {
-//      data: T,
+//     data: T,
 // }
 //
 // impl<T: Clone> Ctx<T> {
-//
+//     $0
 // }
 // ```
 pub(crate) fn add_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
@@ -50,30 +47,37 @@ pub(crate) fn add_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
             let generic_params = lifetime_params.chain(type_params).sep_by(", ");
             format_to!(buf, "<{}>", generic_params)
         }
-        buf.push_str(" {\n");
-        edit.set_cursor(start_offset + TextSize::of(&buf));
-        buf.push_str("\n}");
-        edit.insert(start_offset, buf);
+        match ctx.config.snippet_cap {
+            Some(cap) => {
+                buf.push_str(" {\n    $0\n}");
+                edit.insert_snippet(cap, start_offset, buf);
+            }
+            None => {
+                buf.push_str(" {\n}");
+                edit.insert(start_offset, buf);
+            }
+        }
     })
 }
 
 #[cfg(test)]
 mod tests {
-    use super::*;
     use crate::tests::{check_assist, check_assist_target};
 
+    use super::*;
+
     #[test]
     fn test_add_impl() {
-        check_assist(add_impl, "struct Foo {<|>}\n", "struct Foo {}\n\nimpl Foo {\n<|>\n}\n");
+        check_assist(add_impl, "struct Foo {<|>}\n", "struct Foo {}\n\nimpl Foo {\n    $0\n}\n");
         check_assist(
             add_impl,
             "struct Foo<T: Clone> {<|>}",
-            "struct Foo<T: Clone> {}\n\nimpl<T: Clone> Foo<T> {\n<|>\n}",
+            "struct Foo<T: Clone> {}\n\nimpl<T: Clone> Foo<T> {\n    $0\n}",
         );
         check_assist(
             add_impl,
             "struct Foo<'a, T: Foo<'a>> {<|>}",
-            "struct Foo<'a, T: Foo<'a>> {}\n\nimpl<'a, T: Foo<'a>> Foo<'a, T> {\n<|>\n}",
+            "struct Foo<'a, T: Foo<'a>> {}\n\nimpl<'a, T: Foo<'a>> Foo<'a, T> {\n    $0\n}",
         );
     }
 
diff --git a/crates/ra_assists/src/handlers/add_missing_impl_members.rs b/crates/ra_assists/src/handlers/add_missing_impl_members.rs
index 22e1156d2..abacd4065 100644
--- a/crates/ra_assists/src/handlers/add_missing_impl_members.rs
+++ b/crates/ra_assists/src/handlers/add_missing_impl_members.rs
@@ -11,7 +11,7 @@ use ra_syntax::{
 use crate::{
     assist_context::{AssistContext, Assists},
     ast_transform::{self, AstTransform, QualifyPaths, SubstituteTypeParams},
-    utils::{get_missing_assoc_items, resolve_target_trait},
+    utils::{get_missing_assoc_items, render_snippet, resolve_target_trait, Cursor},
     AssistId,
 };
 
@@ -46,7 +46,7 @@ enum AddMissingImplMembersMode {
 //
 // impl Trait<u32> for () {
 //     fn foo(&self) -> u32 {
-//         todo!()
+//         ${0:todo!()}
 //     }
 //
 // }
@@ -89,7 +89,7 @@ pub(crate) fn add_missing_impl_members(acc: &mut Assists, ctx: &AssistContext) -
 // impl Trait for () {
 //     Type X = ();
 //     fn foo(&self) {}
-//     fn bar(&self) {}
+//     $0fn bar(&self) {}
 //
 // }
 // ```
@@ -147,7 +147,7 @@ fn add_missing_impl_members_inner(
     }
 
     let target = impl_def.syntax().text_range();
-    acc.add(AssistId(assist_id), label, target, |edit| {
+    acc.add(AssistId(assist_id), label, target, |builder| {
         let n_existing_items = impl_item_list.assoc_items().count();
         let source_scope = ctx.sema.scope_for_def(trait_);
         let target_scope = ctx.sema.scope(impl_item_list.syntax());
@@ -162,13 +162,29 @@ fn add_missing_impl_members_inner(
             })
             .map(|it| edit::remove_attrs_and_docs(&it));
         let new_impl_item_list = impl_item_list.append_items(items);
-        let cursor_position = {
-            let first_new_item = new_impl_item_list.assoc_items().nth(n_existing_items).unwrap();
-            first_new_item.syntax().text_range().start()
+        let first_new_item = new_impl_item_list.assoc_items().nth(n_existing_items).unwrap();
+
+        let original_range = impl_item_list.syntax().text_range();
+        match ctx.config.snippet_cap {
+            None => builder.replace(original_range, new_impl_item_list.to_string()),
+            Some(cap) => {
+                let mut cursor = Cursor::Before(first_new_item.syntax());
+                let placeholder;
+                if let ast::AssocItem::FnDef(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,
+                    original_range,
+                    render_snippet(cap, new_impl_item_list.syntax(), cursor),
+                )
+            }
         };
-
-        edit.replace_ast(impl_item_list, new_impl_item_list);
-        edit.set_cursor(cursor_position);
     })
 }
 
@@ -222,7 +238,7 @@ struct S;
 
 impl Foo for S {
     fn bar(&self) {}
-    <|>type Output;
+    $0type Output;
     const CONST: usize = 42;
     fn foo(&self) {
         todo!()
@@ -263,8 +279,8 @@ struct S;
 
 impl Foo for S {
     fn bar(&self) {}
-    <|>fn foo(&self) {
-        todo!()
+    fn foo(&self) {
+        ${0:todo!()}
     }
 
 }"#,
@@ -283,8 +299,8 @@ impl Foo for S { <|> }"#,
 trait Foo { fn foo(&self); }
 struct S;
 impl Foo for S {
-    <|>fn foo(&self) {
-        todo!()
+    fn foo(&self) {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -302,8 +318,8 @@ impl Foo<u32> for S { <|> }"#,
 trait Foo<T> { fn foo(&self, t: T) -> &T; }
 struct S;
 impl Foo<u32> for S {
-    <|>fn foo(&self, t: u32) -> &u32 {
-        todo!()
+    fn foo(&self, t: u32) -> &u32 {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -321,8 +337,8 @@ impl<U> Foo<U> for S { <|> }"#,
 trait Foo<T> { fn foo(&self, t: T) -> &T; }
 struct S;
 impl<U> Foo<U> for S {
-    <|>fn foo(&self, t: U) -> &U {
-        todo!()
+    fn foo(&self, t: U) -> &U {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -340,8 +356,8 @@ impl Foo for S {}<|>"#,
 trait Foo { fn foo(&self); }
 struct S;
 impl Foo for S {
-    <|>fn foo(&self) {
-        todo!()
+    fn foo(&self) {
+        ${0:todo!()}
     }
 }"#,
         )
@@ -365,8 +381,8 @@ mod foo {
 }
 struct S;
 impl foo::Foo for S {
-    <|>fn foo(&self, bar: foo::Bar) {
-        todo!()
+    fn foo(&self, bar: foo::Bar) {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -390,8 +406,8 @@ mod foo {
 }
 struct S;
 impl foo::Foo for S {
-    <|>fn foo(&self, bar: foo::Bar<u32>) {
-        todo!()
+    fn foo(&self, bar: foo::Bar<u32>) {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -415,8 +431,8 @@ mod foo {
 }
 struct S;
 impl foo::Foo<u32> for S {
-    <|>fn foo(&self, bar: foo::Bar<u32>) {
-        todo!()
+    fn foo(&self, bar: foo::Bar<u32>) {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -443,8 +459,8 @@ mod foo {
 struct Param;
 struct S;
 impl foo::Foo<Param> for S {
-    <|>fn foo(&self, bar: Param) {
-        todo!()
+    fn foo(&self, bar: Param) {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -470,8 +486,8 @@ mod foo {
 }
 struct S;
 impl foo::Foo for S {
-    <|>fn foo(&self, bar: foo::Bar<u32>::Assoc) {
-        todo!()
+    fn foo(&self, bar: foo::Bar<u32>::Assoc) {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -497,8 +513,8 @@ mod foo {
 }
 struct S;
 impl foo::Foo for S {
-    <|>fn foo(&self, bar: foo::Bar<foo::Baz>) {
-        todo!()
+    fn foo(&self, bar: foo::Bar<foo::Baz>) {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -522,8 +538,8 @@ mod foo {
 }
 struct S;
 impl foo::Foo for S {
-    <|>fn foo(&self, bar: dyn Fn(u32) -> i32) {
-        todo!()
+    fn foo(&self, bar: dyn Fn(u32) -> i32) {
+        ${0:todo!()}
     }
 }"#,
         );
@@ -580,7 +596,7 @@ trait Foo {
 }
 struct S;
 impl Foo for S {
-    <|>type Output;
+    $0type Output;
     fn foo(&self) {
         todo!()
     }
@@ -614,7 +630,7 @@ trait Foo {
 }
 struct S;
 impl Foo for S {
-    <|>fn valid(some: u32) -> bool { false }
+    $0fn valid(some: u32) -> bool { false }
 }"#,
         )
     }
@@ -637,8 +653,8 @@ trait Foo<T = Self> {
 
 struct S;
 impl Foo for S {
-    <|>fn bar(&self, other: &Self) {
-        todo!()
+    fn bar(&self, other: &Self) {
+        ${0:todo!()}
     }
 }"#,
         )
@@ -662,8 +678,8 @@ trait Foo<T1, T2 = Self> {
 
 struct S<T>;
 impl Foo<T> for S<T> {
-    <|>fn bar(&self, this: &T, that: &Self) {
-        todo!()
+    fn bar(&self, this: &T, that: &Self) {
+        ${0:todo!()}
     }
 }"#,
         )
diff --git a/crates/ra_assists/src/handlers/add_new.rs b/crates/ra_assists/src/handlers/add_new.rs
index fe7451dcf..837aa8377 100644
--- a/crates/ra_assists/src/handlers/add_new.rs
+++ b/crates/ra_assists/src/handlers/add_new.rs
@@ -3,7 +3,7 @@ use ra_syntax::{
     ast::{
         self, AstNode, NameOwner, StructKind, TypeAscriptionOwner, TypeParamsOwner, VisibilityOwner,
     },
-    TextSize, T,
+    T,
 };
 use stdx::{format_to, SepBy};
 
@@ -25,7 +25,7 @@ use crate::{AssistContext, AssistId, Assists};
 // }
 //
 // impl<T: Clone> Ctx<T> {
-//     fn new(data: T) -> Self { Self { data } }
+//     fn $0new(data: T) -> Self { Self { data } }
 // }
 //
 // ```
@@ -42,31 +42,26 @@ pub(crate) fn add_new(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     let impl_def = find_struct_impl(&ctx, &strukt)?;
 
     let target = strukt.syntax().text_range();
-    acc.add(AssistId("add_new"), "Add default constructor", target, |edit| {
+    acc.add(AssistId("add_new"), "Add default constructor", target, |builder| {
         let mut buf = String::with_capacity(512);
 
         if impl_def.is_some() {
             buf.push('\n');
         }
 
-        let vis = strukt.visibility().map(|v| format!("{} ", v));
-        let vis = vis.as_deref().unwrap_or("");
+        let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
 
         let params = field_list
             .fields()
             .filter_map(|f| {
-                Some(format!(
-                    "{}: {}",
-                    f.name()?.syntax().text(),
-                    f.ascribed_type()?.syntax().text()
-                ))
+                Some(format!("{}: {}", f.name()?.syntax(), f.ascribed_type()?.syntax()))
             })
             .sep_by(", ");
         let fields = field_list.fields().filter_map(|f| f.name()).sep_by(", ");
 
         format_to!(buf, "    {}fn new({}) -> Self {{ Self {{ {} }} }}", vis, params, fields);
 
-        let (start_offset, end_offset) = impl_def
+        let start_offset = impl_def
             .and_then(|impl_def| {
                 buf.push('\n');
                 let start = impl_def
@@ -76,17 +71,20 @@ pub(crate) fn add_new(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
                     .text_range()
                     .end();
 
-                Some((start, TextSize::of("\n")))
+                Some(start)
             })
             .unwrap_or_else(|| {
                 buf = generate_impl_text(&strukt, &buf);
-                let start = strukt.syntax().text_range().end();
-
-                (start, TextSize::of("\n}\n"))
+                strukt.syntax().text_range().end()
             });
 
-        edit.set_cursor(start_offset + TextSize::of(&buf) - end_offset);
-        edit.insert(start_offset, buf);
+        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);
+            }
+        }
     })
 }
 
@@ -191,7 +189,7 @@ mod tests {
 "struct Foo {}
 
 impl Foo {
-    fn new() -> Self { Self {  } }<|>
+    fn $0new() -> Self { Self {  } }
 }
 ",
         );
@@ -201,7 +199,7 @@ impl Foo {
 "struct Foo<T: Clone> {}
 
 impl<T: Clone> Foo<T> {
-    fn new() -> Self { Self {  } }<|>
+    fn $0new() -> Self { Self {  } }
 }
 ",
         );
@@ -211,7 +209,7 @@ impl<T: Clone> Foo<T> {
 "struct Foo<'a, T: Foo<'a>> {}
 
 impl<'a, T: Foo<'a>> Foo<'a, T> {
-    fn new() -> Self { Self {  } }<|>
+    fn $0new() -> Self { Self {  } }
 }
 ",
         );
@@ -221,7 +219,7 @@ impl<'a, T: Foo<'a>> Foo<'a, T> {
 "struct Foo { baz: String }
 
 impl Foo {
-    fn new(baz: String) -> Self { Self { baz } }<|>
+    fn $0new(baz: String) -> Self { Self { baz } }
 }
 ",
         );
@@ -231,7 +229,7 @@ impl Foo {
 "struct Foo { baz: String, qux: Vec<i32> }
 
 impl Foo {
-    fn new(baz: String, qux: Vec<i32>) -> Self { Self { baz, qux } }<|>
+    fn $0new(baz: String, qux: Vec<i32>) -> Self { Self { baz, qux } }
 }
 ",
         );
@@ -243,7 +241,7 @@ impl Foo {
 "struct Foo { pub baz: String, pub qux: Vec<i32> }
 
 impl Foo {
-    fn new(baz: String, qux: Vec<i32>) -> Self { Self { baz, qux } }<|>
+    fn $0new(baz: String, qux: Vec<i32>) -> Self { Self { baz, qux } }
 }
 ",
         );
@@ -258,7 +256,7 @@ impl Foo {}
 "struct Foo {}
 
 impl Foo {
-    fn new() -> Self { Self {  } }<|>
+    fn $0new() -> Self { Self {  } }
 }
 ",
         );
@@ -273,7 +271,7 @@ impl Foo {
 "struct Foo {}
 
 impl Foo {
-    fn new() -> Self { Self {  } }<|>
+    fn $0new() -> Self { Self {  } }
 
     fn qux(&self) {}
 }
@@ -294,7 +292,7 @@ impl Foo {
 "struct Foo {}
 
 impl Foo {
-    fn new() -> Self { Self {  } }<|>
+    fn $0new() -> Self { Self {  } }
 
     fn qux(&self) {}
     fn baz() -> i32 {
@@ -311,7 +309,7 @@ impl Foo {
 "pub struct Foo {}
 
 impl Foo {
-    pub fn new() -> Self { Self {  } }<|>
+    pub fn $0new() -> Self { Self {  } }
 }
 ",
         );
@@ -321,7 +319,7 @@ impl Foo {
 "pub(crate) struct Foo {}
 
 impl Foo {
-    pub(crate) fn new() -> Self { Self {  } }<|>
+    pub(crate) fn $0new() -> Self { Self {  } }
 }
 ",
         );
@@ -414,7 +412,7 @@ pub struct Source<T> {
 }
 
 impl<T> Source<T> {
-    pub fn new(file_id: HirFileId, ast: T) -> Self { Self { file_id, ast } }<|>
+    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/ra_assists/src/handlers/add_turbo_fish.rs b/crates/ra_assists/src/handlers/add_turbo_fish.rs
new file mode 100644
index 000000000..26acf81f2
--- /dev/null
+++ b/crates/ra_assists/src/handlers/add_turbo_fish.rs
@@ -0,0 +1,134 @@
+use ra_ide_db::defs::{classify_name_ref, Definition, NameRefClass};
+use ra_syntax::{ast, AstNode, SyntaxKind, T};
+use test_utils::mark;
+
+use crate::{
+    assist_context::{AssistContext, Assists},
+    AssistId,
+};
+
+// Assist: add_turbo_fish
+//
+// Adds `::<_>` to a call of a generic method or function.
+//
+// ```
+// fn make<T>() -> T { todo!() }
+// fn main() {
+//     let x = make<|>();
+// }
+// ```
+// ->
+// ```
+// fn make<T>() -> T { todo!() }
+// fn main() {
+//     let x = make::<${0:_}>();
+// }
+// ```
+pub(crate) fn add_turbo_fish(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let ident = ctx.find_token_at_offset(SyntaxKind::IDENT)?;
+    let next_token = ident.next_token()?;
+    if next_token.kind() == T![::] {
+        mark::hit!(add_turbo_fish_one_fish_is_enough);
+        return None;
+    }
+    let name_ref = ast::NameRef::cast(ident.parent())?;
+    let def = match classify_name_ref(&ctx.sema, &name_ref)? {
+        NameRefClass::Definition(def) => def,
+        NameRefClass::FieldShorthand { .. } => return None,
+    };
+    let fun = match def {
+        Definition::ModuleDef(hir::ModuleDef::Function(it)) => it,
+        _ => return None,
+    };
+    let generics = hir::GenericDef::Function(fun).params(ctx.sema.db);
+    if generics.is_empty() {
+        mark::hit!(add_turbo_fish_non_generic);
+        return None;
+    }
+    acc.add(AssistId("add_turbo_fish"), "Add `::<>`", ident.text_range(), |builder| {
+        match ctx.config.snippet_cap {
+            Some(cap) => builder.insert_snippet(cap, ident.text_range().end(), "::<${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<|>();
+}
+"#,
+            r#"
+fn make<T>() -> T {}
+fn main() {
+    make::<${0:_}>();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn add_turbo_fish_method() {
+        check_assist(
+            add_turbo_fish,
+            r#"
+struct S;
+impl S {
+    fn make<T>(&self) -> T {}
+}
+fn main() {
+    S.make<|>();
+}
+"#,
+            r#"
+struct S;
+impl S {
+    fn make<T>(&self) -> T {}
+}
+fn main() {
+    S.make::<${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<|>::<()>();
+}
+"#,
+        );
+    }
+
+    #[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<|>();
+}
+"#,
+        );
+    }
+}
diff --git a/crates/ra_assists/src/handlers/apply_demorgan.rs b/crates/ra_assists/src/handlers/apply_demorgan.rs
index 0feba5e11..233e8fb8e 100644
--- a/crates/ra_assists/src/handlers/apply_demorgan.rs
+++ b/crates/ra_assists/src/handlers/apply_demorgan.rs
@@ -63,22 +63,22 @@ mod tests {
 
     #[test]
     fn demorgan_turns_and_into_or() {
-        check_assist(apply_demorgan, "fn f() { !x &&<|> !x }", "fn f() { !(x ||<|> x) }")
+        check_assist(apply_demorgan, "fn f() { !x &&<|> !x }", "fn f() { !(x || x) }")
     }
 
     #[test]
     fn demorgan_turns_or_into_and() {
-        check_assist(apply_demorgan, "fn f() { !x ||<|> !x }", "fn f() { !(x &&<|> x) }")
+        check_assist(apply_demorgan, "fn f() { !x ||<|> !x }", "fn f() { !(x && x) }")
     }
 
     #[test]
     fn demorgan_removes_inequality() {
-        check_assist(apply_demorgan, "fn f() { x != x ||<|> !x }", "fn f() { !(x == x &&<|> x) }")
+        check_assist(apply_demorgan, "fn f() { x != x ||<|> !x }", "fn f() { !(x == x && x) }")
     }
 
     #[test]
     fn demorgan_general_case() {
-        check_assist(apply_demorgan, "fn f() { x ||<|> x }", "fn f() { !(!x &&<|> !x) }")
+        check_assist(apply_demorgan, "fn f() { x ||<|> x }", "fn f() { !(!x && !x) }")
     }
 
     #[test]
diff --git a/crates/ra_assists/src/handlers/auto_import.rs b/crates/ra_assists/src/handlers/auto_import.rs
index 78d23150d..edf96d50e 100644
--- a/crates/ra_assists/src/handlers/auto_import.rs
+++ b/crates/ra_assists/src/handlers/auto_import.rs
@@ -50,7 +50,12 @@ pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
             format!("Import `{}`", &import),
             range,
             |builder| {
-                insert_use_statement(&auto_import_assets.syntax_under_caret, &import, ctx, builder);
+                insert_use_statement(
+                    &auto_import_assets.syntax_under_caret,
+                    &import,
+                    ctx,
+                    builder.text_edit_builder(),
+                );
             },
         );
     }
@@ -293,7 +298,7 @@ mod tests {
             }
             ",
             r"
-            <|>use PubMod::PubStruct;
+            use PubMod::PubStruct;
 
             PubStruct
 
@@ -324,7 +329,7 @@ mod tests {
             macro_rules! foo {
                 ($i:ident) => { fn foo(a: $i) {} }
             }
-            foo!(Pub<|>Struct);
+            foo!(PubStruct);
 
             pub mod PubMod {
                 pub struct PubStruct;
@@ -355,7 +360,7 @@ mod tests {
             use PubMod::{PubStruct2, PubStruct1};
 
             struct Test {
-                test: Pub<|>Struct2<u8>,
+                test: PubStruct2<u8>,
             }
 
             pub mod PubMod {
@@ -388,7 +393,7 @@ mod tests {
             r"
             use PubMod3::PubStruct;
 
-            PubSt<|>ruct
+            PubStruct
 
             pub mod PubMod1 {
                 pub struct PubStruct;
@@ -469,7 +474,7 @@ mod tests {
             r"
             use PubMod::test_function;
 
-            test_function<|>
+            test_function
 
             pub mod PubMod {
                 pub fn test_function() {};
@@ -496,7 +501,7 @@ mod tests {
             r"use crate_with_macro::foo;
 
 fn main() {
-    foo<|>
+    foo
 }
 ",
         );
@@ -582,7 +587,7 @@ fn main() {
             }
 
             fn main() {
-                TestStruct::test_function<|>
+                TestStruct::test_function
             }
             ",
         );
@@ -615,7 +620,7 @@ fn main() {
             }
 
             fn main() {
-                TestStruct::TEST_CONST<|>
+                TestStruct::TEST_CONST
             }
             ",
         );
@@ -654,7 +659,7 @@ fn main() {
             }
 
             fn main() {
-                test_mod::TestStruct::test_function<|>
+                test_mod::TestStruct::test_function
             }
             ",
         );
@@ -725,7 +730,7 @@ fn main() {
             }
 
             fn main() {
-                test_mod::TestStruct::TEST_CONST<|>
+                test_mod::TestStruct::TEST_CONST
             }
             ",
         );
@@ -798,7 +803,7 @@ fn main() {
 
             fn main() {
                 let test_struct = test_mod::TestStruct {};
-                test_struct.test_meth<|>od()
+                test_struct.test_method()
             }
             ",
         );
diff --git a/crates/ra_assists/src/handlers/change_return_type_to_result.rs b/crates/ra_assists/src/handlers/change_return_type_to_result.rs
index 5c907097e..c6baa0a57 100644
--- a/crates/ra_assists/src/handlers/change_return_type_to_result.rs
+++ b/crates/ra_assists/src/handlers/change_return_type_to_result.rs
@@ -1,8 +1,6 @@
 use ra_syntax::{
     ast::{self, BlockExpr, Expr, LoopBodyOwner},
-    AstNode,
-    SyntaxKind::{COMMENT, WHITESPACE},
-    SyntaxNode, TextSize,
+    AstNode, SyntaxNode,
 };
 
 use crate::{AssistContext, AssistId, Assists};
@@ -16,39 +14,40 @@ use crate::{AssistContext, AssistId, Assists};
 // ```
 // ->
 // ```
-// fn foo() -> Result<i32, > { Ok(42i32) }
+// fn foo() -> Result<i32, ${0:_}> { Ok(42i32) }
 // ```
 pub(crate) fn change_return_type_to_result(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let fn_def = ctx.find_node_at_offset::<ast::FnDef>();
-    let fn_def = &mut fn_def?;
-    let ret_type = &fn_def.ret_type()?.type_ref()?;
-    if ret_type.syntax().text().to_string().starts_with("Result<") {
+    let ret_type = ctx.find_node_at_offset::<ast::RetType>()?;
+    // FIXME: extend to lambdas as well
+    let fn_def = ret_type.syntax().parent().and_then(ast::FnDef::cast)?;
+
+    let type_ref = &ret_type.type_ref()?;
+    if type_ref.syntax().text().to_string().starts_with("Result<") {
         return None;
     }
 
     let block_expr = &fn_def.body()?;
-    let cursor_in_ret_type =
-        fn_def.ret_type()?.syntax().text_range().contains_range(ctx.frange.range);
-    if !cursor_in_ret_type {
-        return None;
-    }
 
     acc.add(
         AssistId("change_return_type_to_result"),
         "Change return type to Result",
-        ret_type.syntax().text_range(),
-        |edit| {
+        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 {
-                edit.replace_node_and_indent(&ret_expr_arg, format!("Ok({})", ret_expr_arg));
+                builder.replace_node_and_indent(&ret_expr_arg, format!("Ok({})", ret_expr_arg));
             }
-            edit.replace_node_and_indent(ret_type.syntax(), format!("Result<{}, >", ret_type));
 
-            if let Some(node_start) = result_insertion_offset(&ret_type) {
-                edit.set_cursor(node_start + TextSize::of(&format!("Result<{}, ", ret_type)));
+            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)),
             }
         },
     )
@@ -250,17 +249,8 @@ fn get_tail_expr_from_block(expr: &Expr) -> Option<Vec<NodeType>> {
     }
 }
 
-fn result_insertion_offset(ret_type: &ast::TypeRef) -> Option<TextSize> {
-    let non_ws_child = ret_type
-        .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_not_applicable};
 
     use super::*;
@@ -273,7 +263,7 @@ mod tests {
                 let test = "test";
                 return 42i32;
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let test = "test";
                 return Ok(42i32);
             }"#,
@@ -288,7 +278,7 @@ mod tests {
                 let test = "test";
                 return 42i32;
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let test = "test";
                 return Ok(42i32);
             }"#,
@@ -314,7 +304,7 @@ mod tests {
                 let test = "test";
                 return 42i32;
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let test = "test";
                 return Ok(42i32);
             }"#,
@@ -329,7 +319,7 @@ mod tests {
                 let test = "test";
                 42i32
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let test = "test";
                 Ok(42i32)
             }"#,
@@ -343,7 +333,7 @@ mod tests {
             r#"fn foo() -> i32<|> {
                 42i32
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 Ok(42i32)
             }"#,
         );
@@ -359,7 +349,7 @@ mod tests {
                     24i32
                 }
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 if true {
                     Ok(42i32)
                 } else {
@@ -384,7 +374,7 @@ mod tests {
                     24i32
                 }
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 if true {
                     if false {
                         Ok(1)
@@ -413,7 +403,7 @@ mod tests {
                     24i32.await
                 }
             }"#,
-            r#"async fn foo() -> Result<i32, <|>> {
+            r#"async fn foo() -> Result<i32, ${0:_}> {
                 if true {
                     if false {
                         Ok(1.await)
@@ -434,7 +424,7 @@ mod tests {
             r#"fn foo() -> [i32;<|> 3] {
                 [1, 2, 3]
             }"#,
-            r#"fn foo() -> Result<[i32; 3], <|>> {
+            r#"fn foo() -> Result<[i32; 3], ${0:_}> {
                 Ok([1, 2, 3])
             }"#,
         );
@@ -455,7 +445,7 @@ mod tests {
                     24 as i32
                 }
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 if true {
                     if false {
                         Ok(1 as i32)
@@ -480,7 +470,7 @@ mod tests {
                     _ => 24i32,
                 }
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let my_var = 5;
                 match my_var {
                     5 => Ok(42i32),
@@ -503,7 +493,7 @@ mod tests {
 
                 my_var
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let my_var = 5;
                 loop {
                     println!("test");
@@ -526,7 +516,7 @@ mod tests {
 
                 my_var
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let my_var = let x = loop {
                     break 1;
                 };
@@ -549,7 +539,7 @@ mod tests {
 
                 res
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let my_var = 5;
                 let res = match my_var {
                     5 => 42i32,
@@ -572,7 +562,7 @@ mod tests {
 
                 res
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let my_var = 5;
                 let res = if my_var == 5 {
                     42i32
@@ -608,7 +598,7 @@ mod tests {
                     },
                 }
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let my_var = 5;
                 match my_var {
                     5 => {
@@ -641,7 +631,7 @@ mod tests {
                 }
                 53i32
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let test = "test";
                 if test == "test" {
                     return Ok(24i32);
@@ -672,7 +662,7 @@ mod tests {
 
                 the_field
             }"#,
-            r#"fn foo(the_field: u32) -> Result<u32, <|>> {
+            r#"fn foo(the_field: u32) -> Result<u32, ${0:_}> {
                 let true_closure = || {
                     return true;
                 };
@@ -711,7 +701,7 @@ mod tests {
 
                 t.unwrap_or_else(|| the_field)
             }"#,
-            r#"fn foo(the_field: u32) -> Result<u32, <|>> {
+            r#"fn foo(the_field: u32) -> Result<u32, ${0:_}> {
                 let true_closure = || {
                     return true;
                 };
@@ -749,7 +739,7 @@ mod tests {
                     i += 1;
                 }
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let test = "test";
                 if test == "test" {
                     return Ok(24i32);
@@ -781,7 +771,7 @@ mod tests {
                     }
                 }
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let test = "test";
                 if test == "test" {
                     return Ok(24i32);
@@ -819,7 +809,7 @@ mod tests {
                     }
                 }
             }"#,
-            r#"fn foo() -> Result<i32, <|>> {
+            r#"fn foo() -> Result<i32, ${0:_}> {
                 let test = "test";
                 let other = 5;
                 if test == "test" {
@@ -860,7 +850,7 @@ mod tests {
 
                 the_field
             }"#,
-            r#"fn foo(the_field: u32) -> Result<u32, <|>> {
+            r#"fn foo(the_field: u32) -> Result<u32, ${0:_}> {
                 if the_field < 5 {
                     let mut i = 0;
                     loop {
@@ -894,7 +884,7 @@ mod tests {
 
                 the_field
             }"#,
-            r#"fn foo(the_field: u32) -> Result<u32, <|>> {
+            r#"fn foo(the_field: u32) -> Result<u32, ${0:_}> {
                 if the_field < 5 {
                     let mut i = 0;
 
@@ -923,7 +913,7 @@ mod tests {
 
                 the_field
             }"#,
-            r#"fn foo(the_field: u32) -> Result<u32, <|>> {
+            r#"fn foo(the_field: u32) -> Result<u32, ${0:_}> {
                 if the_field < 5 {
                     let mut i = 0;
 
@@ -953,7 +943,7 @@ mod tests {
 
                 the_field
             }"#,
-            r#"fn foo(the_field: u32) -> Result<u32, <|>> {
+            r#"fn foo(the_field: u32) -> Result<u32, ${0:_}> {
                 if the_field < 5 {
                     let mut i = 0;
 
diff --git a/crates/ra_assists/src/handlers/change_visibility.rs b/crates/ra_assists/src/handlers/change_visibility.rs
index 40cf4b422..c21d75be0 100644
--- a/crates/ra_assists/src/handlers/change_visibility.rs
+++ b/crates/ra_assists/src/handlers/change_visibility.rs
@@ -5,14 +5,11 @@ use ra_syntax::{
         ATTR, COMMENT, CONST_DEF, ENUM_DEF, FN_DEF, MODULE, STRUCT_DEF, TRAIT_DEF, VISIBILITY,
         WHITESPACE,
     },
-    SyntaxNode, TextRange, TextSize, T,
+    SyntaxNode, TextSize, T,
 };
-
-use hir::{db::HirDatabase, HasSource, HasVisibility, PathResolution};
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{AssistContext, AssistId, Assists};
-use ra_db::FileId;
 
 // Assist: change_visibility
 //
@@ -30,8 +27,6 @@ pub(crate) fn change_visibility(acc: &mut Assists, ctx: &AssistContext) -> Optio
         return change_vis(acc, vis);
     }
     add_vis(acc, ctx)
-        .or_else(|| add_vis_to_referenced_module_def(acc, ctx))
-        .or_else(|| add_vis_to_referenced_record_field(acc, ctx))
 }
 
 fn add_vis(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
@@ -55,7 +50,7 @@ fn add_vis(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     } else if let Some(field_name) = ctx.find_node_at_offset::<ast::Name>() {
         let field = field_name.syntax().ancestors().find_map(ast::RecordFieldDef::cast)?;
         if field.name()? != field_name {
-            tested_by!(change_visibility_field_false_positive);
+            mark::hit!(change_visibility_field_false_positive);
             return None;
         }
         if field.visibility().is_some() {
@@ -73,147 +68,9 @@ fn add_vis(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
 
     acc.add(AssistId("change_visibility"), "Change visibility to pub(crate)", target, |edit| {
         edit.insert(offset, "pub(crate) ");
-        edit.set_cursor(offset);
-    })
-}
-
-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, 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("change_visibility"), assist_label, target, |edit| {
-        edit.set_file(target_file);
-        edit.insert(offset, format!("{} ", missing_visibility));
-        edit.set_cursor(offset);
-    })
-}
-
-fn add_vis_to_referenced_record_field(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let record_field: ast::RecordField = 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, target) = match in_file_source.value {
-        hir::FieldSource::Named(it) => {
-            let s = it.syntax();
-            (vis_offset(s), s.text_range())
-        }
-        hir::FieldSource::Pos(it) => {
-            let s = it.syntax();
-            (vis_offset(s), 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("change_visibility"), assist_label, target, |edit| {
-        edit.set_file(target_file);
-        edit.insert(offset, format!("{} ", missing_visibility));
-        edit.set_cursor(offset)
     })
 }
 
-fn target_data_for_def(
-    db: &dyn HirDatabase,
-    def: hir::ModuleDef,
-) -> Option<(TextSize, TextRange, FileId, Option<hir::Name>)> {
-    fn offset_target_and_file_id<S, Ast>(
-        db: &dyn HirDatabase,
-        x: S,
-    ) -> (TextSize, TextRange, FileId)
-    where
-        S: HasSource<Ast = Ast>,
-        Ast: AstNode,
-    {
-        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;
-        (vis_offset(syntax), syntax.text_range(), file_id.original_file(db.upcast()))
-    }
-
-    let target_name;
-    let (offset, 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), syntax.text_range(), file_id)
-        }
-        // Enum variants can't be private, we can't modify builtin types
-        hir::ModuleDef::EnumVariant(_) | hir::ModuleDef::BuiltinType(_) => return None,
-    };
-
-    Some((offset, target, target_file, target_name))
-}
-
 fn vis_offset(node: &SyntaxNode) -> TextSize {
     node.children_with_tokens()
         .skip_while(|it| match it.kind() {
@@ -234,7 +91,6 @@ fn change_vis(acc: &mut Assists, vis: ast::Visibility) -> Option<()> {
             target,
             |edit| {
                 edit.replace(vis.syntax().text_range(), "pub(crate)");
-                edit.set_cursor(vis.syntax().text_range().start())
             },
         );
     }
@@ -246,7 +102,6 @@ fn change_vis(acc: &mut Assists, vis: ast::Visibility) -> Option<()> {
             target,
             |edit| {
                 edit.replace(vis.syntax().text_range(), "pub");
-                edit.set_cursor(vis.syntax().text_range().start());
             },
         );
     }
@@ -255,7 +110,7 @@ fn change_vis(acc: &mut Assists, vis: ast::Visibility) -> Option<()> {
 
 #[cfg(test)]
 mod tests {
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
 
@@ -263,17 +118,13 @@ mod tests {
 
     #[test]
     fn change_visibility_adds_pub_crate_to_items() {
-        check_assist(change_visibility, "<|>fn foo() {}", "<|>pub(crate) fn foo() {}");
-        check_assist(change_visibility, "f<|>n foo() {}", "<|>pub(crate) fn foo() {}");
-        check_assist(change_visibility, "<|>struct Foo {}", "<|>pub(crate) struct Foo {}");
-        check_assist(change_visibility, "<|>mod foo {}", "<|>pub(crate) mod foo {}");
-        check_assist(change_visibility, "<|>trait Foo {}", "<|>pub(crate) trait Foo {}");
-        check_assist(change_visibility, "m<|>od {}", "<|>pub(crate) mod {}");
-        check_assist(
-            change_visibility,
-            "unsafe f<|>n foo() {}",
-            "<|>pub(crate) unsafe fn foo() {}",
-        );
+        check_assist(change_visibility, "<|>fn foo() {}", "pub(crate) fn foo() {}");
+        check_assist(change_visibility, "f<|>n foo() {}", "pub(crate) fn foo() {}");
+        check_assist(change_visibility, "<|>struct Foo {}", "pub(crate) struct Foo {}");
+        check_assist(change_visibility, "<|>mod foo {}", "pub(crate) mod foo {}");
+        check_assist(change_visibility, "<|>trait Foo {}", "pub(crate) trait Foo {}");
+        check_assist(change_visibility, "m<|>od {}", "pub(crate) mod {}");
+        check_assist(change_visibility, "unsafe f<|>n foo() {}", "pub(crate) unsafe fn foo() {}");
     }
 
     #[test]
@@ -281,14 +132,14 @@ mod tests {
         check_assist(
             change_visibility,
             r"struct S { <|>field: u32 }",
-            r"struct S { <|>pub(crate) field: u32 }",
+            r"struct S { pub(crate) field: u32 }",
         );
-        check_assist(change_visibility, r"struct S ( <|>u32 )", r"struct S ( <|>pub(crate) u32 )");
+        check_assist(change_visibility, r"struct S ( <|>u32 )", r"struct S ( pub(crate) u32 )");
     }
 
     #[test]
     fn change_visibility_field_false_positive() {
-        covers!(change_visibility_field_false_positive);
+        mark::check!(change_visibility_field_false_positive);
         check_assist_not_applicable(
             change_visibility,
             r"struct S { field: [(); { let <|>x = ();}] }",
@@ -297,17 +148,17 @@ mod tests {
 
     #[test]
     fn change_visibility_pub_to_pub_crate() {
-        check_assist(change_visibility, "<|>pub fn foo() {}", "<|>pub(crate) fn foo() {}")
+        check_assist(change_visibility, "<|>pub fn foo() {}", "pub(crate) fn foo() {}")
     }
 
     #[test]
     fn change_visibility_pub_crate_to_pub() {
-        check_assist(change_visibility, "<|>pub(crate) fn foo() {}", "<|>pub fn foo() {}")
+        check_assist(change_visibility, "<|>pub(crate) fn foo() {}", "pub fn foo() {}")
     }
 
     #[test]
     fn change_visibility_const() {
-        check_assist(change_visibility, "<|>const FOO = 3u8;", "<|>pub(crate) const FOO = 3u8;");
+        check_assist(change_visibility, "<|>const FOO = 3u8;", "pub(crate) const FOO = 3u8;");
     }
 
     #[test]
@@ -328,199 +179,12 @@ mod tests {
             // comments
 
             #[derive(Debug)]
-            <|>pub(crate) struct Foo;
+            pub(crate) struct Foo;
             ",
         )
     }
 
     #[test]
-    fn change_visibility_of_fn_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { fn foo() {} }
-              fn main() { foo::foo<|>() } ",
-            r"mod foo { <|>pub(crate) fn foo() {} }
-              fn main() { foo::foo() } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub fn foo() {} }
-              fn main() { foo::foo<|>() } ",
-        )
-    }
-
-    #[test]
-    fn change_visibility_of_adt_in_submodule_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { struct Foo; }
-              fn main() { foo::Foo<|> } ",
-            r"mod foo { <|>pub(crate) struct Foo; }
-              fn main() { foo::Foo } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub struct Foo; }
-              fn main() { foo::Foo<|> } ",
-        );
-        check_assist(
-            change_visibility,
-            r"mod foo { enum Foo; }
-              fn main() { foo::Foo<|> } ",
-            r"mod foo { <|>pub(crate) enum Foo; }
-              fn main() { foo::Foo } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub enum Foo; }
-              fn main() { foo::Foo<|> } ",
-        );
-        check_assist(
-            change_visibility,
-            r"mod foo { union Foo; }
-              fn main() { foo::Foo<|> } ",
-            r"mod foo { <|>pub(crate) union Foo; }
-              fn main() { foo::Foo } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub union Foo; }
-              fn main() { foo::Foo<|> } ",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_adt_in_other_file_via_path() {
-        check_assist(
-            change_visibility,
-            r"
-              //- /main.rs
-              mod foo;
-              fn main() { foo::Foo<|> }
-
-              //- /foo.rs
-              struct Foo;
-              ",
-            r"<|>pub(crate) struct Foo;
-
-",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_struct_field_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { pub struct Foo { bar: (), } }
-              fn main() { foo::Foo { <|>bar: () }; } ",
-            r"mod foo { pub struct Foo { <|>pub(crate) bar: (), } }
-              fn main() { foo::Foo { bar: () }; } ",
-        );
-        check_assist(
-            change_visibility,
-            r"//- /lib.rs
-              mod foo;
-              fn main() { foo::Foo { <|>bar: () }; }
-              //- /foo.rs
-              pub struct Foo { bar: () }
-              ",
-            r"pub struct Foo { <|>pub(crate) bar: () }
-
-",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub struct Foo { pub bar: (), } }
-              fn main() { foo::Foo { <|>bar: () }; } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"//- /lib.rs
-              mod foo;
-              fn main() { foo::Foo { <|>bar: () }; }
-              //- /foo.rs
-              pub struct Foo { pub bar: () }
-              ",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_enum_variant_field_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { pub enum Foo { Bar { bar: () } } }
-              fn main() { foo::Foo::Bar { <|>bar: () }; } ",
-            r"mod foo { pub enum Foo { Bar { <|>pub(crate) bar: () } } }
-              fn main() { foo::Foo::Bar { bar: () }; } ",
-        );
-        check_assist(
-            change_visibility,
-            r"//- /lib.rs
-              mod foo;
-              fn main() { foo::Foo::Bar { <|>bar: () }; }
-              //- /foo.rs
-              pub enum Foo { Bar { bar: () } }
-              ",
-            r"pub enum Foo { Bar { <|>pub(crate) bar: () } }
-
-",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub struct Foo { pub bar: (), } }
-              fn main() { foo::Foo { <|>bar: () }; } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"//- /lib.rs
-              mod foo;
-              fn main() { foo::Foo { <|>bar: () }; }
-              //- /foo.rs
-              pub struct Foo { pub bar: () }
-              ",
-        );
-    }
-
-    #[test]
-    #[ignore]
-    // FIXME reenable this test when `Semantics::resolve_record_field` works with union fields
-    fn change_visibility_of_union_field_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { pub union Foo { bar: (), } }
-              fn main() { foo::Foo { <|>bar: () }; } ",
-            r"mod foo { pub union Foo { <|>pub(crate) bar: (), } }
-              fn main() { foo::Foo { bar: () }; } ",
-        );
-        check_assist(
-            change_visibility,
-            r"//- /lib.rs
-              mod foo;
-              fn main() { foo::Foo { <|>bar: () }; }
-              //- /foo.rs
-              pub union Foo { bar: () }
-              ",
-            r"pub union Foo { <|>pub(crate) bar: () }
-
-",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub union Foo { pub bar: (), } }
-              fn main() { foo::Foo { <|>bar: () }; } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"//- /lib.rs
-              mod foo;
-              fn main() { foo::Foo { <|>bar: () }; }
-              //- /foo.rs
-              pub union Foo { pub bar: () }
-              ",
-        );
-    }
-
-    #[test]
     fn not_applicable_for_enum_variants() {
         check_assist_not_applicable(
             change_visibility,
@@ -530,182 +194,6 @@ mod tests {
     }
 
     #[test]
-    fn change_visibility_of_const_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { const FOO: () = (); }
-              fn main() { foo::FOO<|> } ",
-            r"mod foo { <|>pub(crate) const FOO: () = (); }
-              fn main() { foo::FOO } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub const FOO: () = (); }
-              fn main() { foo::FOO<|> } ",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_static_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { static FOO: () = (); }
-              fn main() { foo::FOO<|> } ",
-            r"mod foo { <|>pub(crate) static FOO: () = (); }
-              fn main() { foo::FOO } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub static FOO: () = (); }
-              fn main() { foo::FOO<|> } ",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_trait_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { trait Foo { fn foo(&self) {} } }
-              fn main() { let x: &dyn foo::<|>Foo; } ",
-            r"mod foo { <|>pub(crate) trait Foo { fn foo(&self) {} } }
-              fn main() { let x: &dyn foo::Foo; } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub trait Foo { fn foo(&self) {} } }
-              fn main() { let x: &dyn foo::Foo<|>; } ",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_type_alias_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { type Foo = (); }
-              fn main() { let x: foo::Foo<|>; } ",
-            r"mod foo { <|>pub(crate) type Foo = (); }
-              fn main() { let x: foo::Foo; } ",
-        );
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub type Foo = (); }
-              fn main() { let x: foo::Foo<|>; } ",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_module_via_path() {
-        check_assist(
-            change_visibility,
-            r"mod foo { mod bar { fn bar() {} } }
-              fn main() { foo::bar<|>::bar(); } ",
-            r"mod foo { <|>pub(crate) mod bar { fn bar() {} } }
-              fn main() { foo::bar::bar(); } ",
-        );
-
-        check_assist(
-            change_visibility,
-            r"
-            //- /main.rs
-            mod foo;
-            fn main() { foo::bar<|>::baz(); }
-
-            //- /foo.rs
-            mod bar {
-                pub fn baz() {}
-            }
-            ",
-            r"<|>pub(crate) mod bar {
-    pub fn baz() {}
-}
-
-",
-        );
-
-        check_assist_not_applicable(
-            change_visibility,
-            r"mod foo { pub mod bar { pub fn bar() {} } }
-              fn main() { foo::bar<|>::bar(); } ",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_inline_module_in_other_file_via_path() {
-        check_assist(
-            change_visibility,
-            r"
-            //- /main.rs
-            mod foo;
-            fn main() { foo::bar<|>::baz(); }
-
-            //- /foo.rs
-            mod bar;
-
-            //- /foo/bar.rs
-            pub fn baz() {}
-            }
-            ",
-            r"<|>pub(crate) mod bar;
-",
-        );
-    }
-
-    #[test]
-    fn change_visibility_of_module_declaration_in_other_file_via_path() {
-        check_assist(
-            change_visibility,
-            r"//- /main.rs
-              mod foo;
-              fn main() { foo::bar<|>>::baz(); }
-
-              //- /foo.rs
-              mod bar {
-                  pub fn baz() {}
-              }",
-            r"<|>pub(crate) mod bar {
-    pub fn baz() {}
-}
-",
-        );
-    }
-
-    #[test]
-    #[ignore]
-    // FIXME handle reexports properly
-    fn change_visibility_of_reexport() {
-        check_assist(
-            change_visibility,
-            r"
-            mod foo {
-                use bar::Baz;
-                mod bar { pub(super) struct Baz; }
-            }
-            foo::Baz<|>
-            ",
-            r"
-            mod foo {
-                <|>pub(crate) use bar::Baz;
-                mod bar { pub(super) struct Baz; }
-            }
-            foo::Baz
-            ",
-        )
-    }
-
-    #[test]
-    fn adds_pub_when_target_is_in_another_crate() {
-        check_assist(
-            change_visibility,
-            r"//- /main.rs crate:a deps:foo
-              foo::Bar<|>
-              //- /lib.rs crate:foo
-              struct Bar;",
-            r"<|>pub struct Bar;
-",
-        )
-    }
-
-    #[test]
     fn change_visibility_target() {
         check_assist_target(change_visibility, "<|>fn foo() {}", "fn");
         check_assist_target(change_visibility, "pub(crate)<|> fn foo() {}", "pub(crate)");
diff --git a/crates/ra_assists/src/handlers/early_return.rs b/crates/ra_assists/src/handlers/early_return.rs
index 66b296081..4cc75a7ce 100644
--- a/crates/ra_assists/src/handlers/early_return.rs
+++ b/crates/ra_assists/src/handlers/early_return.rs
@@ -97,7 +97,6 @@ pub(crate) fn convert_to_guarded_return(acc: &mut Assists, ctx: &AssistContext)
     }
 
     then_block.syntax().last_child_or_token().filter(|t| t.kind() == R_CURLY)?;
-    let cursor_position = ctx.offset();
 
     let target = if_expr.syntax().text_range();
     acc.add(AssistId("convert_to_guarded_return"), "Convert to guarded return", target, |edit| {
@@ -148,7 +147,6 @@ pub(crate) fn convert_to_guarded_return(acc: &mut Assists, ctx: &AssistContext)
             }
         };
         edit.replace_ast(parent_block, ast::BlockExpr::cast(new_block).unwrap());
-        edit.set_cursor(cursor_position);
 
         fn replace(
             new_expr: &SyntaxNode,
@@ -207,7 +205,7 @@ mod tests {
             r#"
             fn main() {
                 bar();
-                if<|> !true {
+                if !true {
                     return;
                 }
                 foo();
@@ -237,7 +235,7 @@ mod tests {
             r#"
             fn main(n: Option<String>) {
                 bar();
-                le<|>t n = match n {
+                let n = match n {
                     Some(it) => it,
                     _ => return,
                 };
@@ -263,7 +261,7 @@ mod tests {
             "#,
             r#"
             fn main() {
-                le<|>t x = match Err(92) {
+                let x = match Err(92) {
                     Ok(it) => it,
                     _ => return,
                 };
@@ -291,7 +289,7 @@ mod tests {
             r#"
             fn main(n: Option<String>) {
                 bar();
-                le<|>t n = match n {
+                let n = match n {
                     Ok(it) => it,
                     _ => return,
                 };
@@ -321,7 +319,7 @@ mod tests {
             r#"
             fn main() {
                 while true {
-                    if<|> !true {
+                    if !true {
                         continue;
                     }
                     foo();
@@ -349,7 +347,7 @@ mod tests {
             r#"
             fn main() {
                 while true {
-                    le<|>t n = match n {
+                    let n = match n {
                         Some(it) => it,
                         _ => continue,
                     };
@@ -378,7 +376,7 @@ mod tests {
             r#"
             fn main() {
                 loop {
-                    if<|> !true {
+                    if !true {
                         continue;
                     }
                     foo();
@@ -406,7 +404,7 @@ mod tests {
             r#"
             fn main() {
                 loop {
-                    le<|>t n = match n {
+                    let n = match n {
                         Some(it) => it,
                         _ => continue,
                     };
diff --git a/crates/ra_assists/src/handlers/fill_match_arms.rs b/crates/ra_assists/src/handlers/fill_match_arms.rs
index 13c1e7e80..cc303285b 100644
--- a/crates/ra_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ra_assists/src/handlers/fill_match_arms.rs
@@ -4,8 +4,12 @@ use hir::{Adt, HasSource, ModuleDef, Semantics};
 use itertools::Itertools;
 use ra_ide_db::RootDatabase;
 use ra_syntax::ast::{self, make, AstNode, MatchArm, NameOwner, Pat};
+use test_utils::mark;
 
-use crate::{AssistContext, AssistId, Assists};
+use crate::{
+    utils::{render_snippet, Cursor, FamousDefs},
+    AssistContext, AssistId, Assists,
+};
 
 // Assist: fill_match_arms
 //
@@ -26,7 +30,7 @@ use crate::{AssistContext, AssistId, Assists};
 //
 // fn handle(action: Action) {
 //     match action {
-//         Action::Move { distance } => {}
+//         $0Action::Move { distance } => {}
 //         Action::Stop => {}
 //     }
 // }
@@ -49,12 +53,18 @@ pub(crate) fn fill_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<
     let missing_arms: Vec<MatchArm> = if let Some(enum_def) = resolve_enum_def(&ctx.sema, &expr) {
         let variants = enum_def.variants(ctx.db);
 
-        variants
+        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()
+            .collect::<Vec<_>>();
+        if Some(enum_def) == FamousDefs(&ctx.sema, 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() {
@@ -93,10 +103,23 @@ pub(crate) fn fill_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<
     }
 
     let target = match_expr.syntax().text_range();
-    acc.add(AssistId("fill_match_arms"), "Fill match arms", target, |edit| {
-        let new_arm_list = match_arm_list.remove_placeholder().append_arms(missing_arms);
-        edit.set_cursor(expr.syntax().text_range().start());
-        edit.replace_ast(match_arm_list, new_arm_list);
+    acc.add(AssistId("fill_match_arms"), "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 = match_arm_list.syntax().text_range();
+        match (first_new_arm, ctx.config.snippet_cap) {
+            (Some(first_new_arm), Some(cap)) => {
+                let snippet = render_snippet(
+                    cap,
+                    new_arm_list.syntax(),
+                    Cursor::Before(first_new_arm.syntax()),
+                );
+                builder.replace_snippet(cap, old_range, snippet);
+            }
+            _ => builder.replace(old_range, new_arm_list.to_string()),
+        }
     })
 }
 
@@ -167,7 +190,12 @@ fn build_pat(db: &RootDatabase, module: hir::Module, var: hir::EnumVariant) -> O
 
 #[cfg(test)]
 mod tests {
-    use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
+    use test_utils::mark;
+
+    use crate::{
+        tests::{check_assist, check_assist_not_applicable, check_assist_target},
+        utils::FamousDefs,
+    };
 
     use super::fill_match_arms;
 
@@ -214,12 +242,12 @@ mod tests {
             r#"
             enum A {
                 As,
-                Bs{x:i32, y:Option<i32>},
+                Bs { x: i32, y: Option<i32> },
                 Cs(i32, Option<i32>),
             }
             fn main() {
                 match A::As<|> {
-                    A::Bs{x,y:Some(_)} => {}
+                    A::Bs { x, y: Some(_) } => {}
                     A::Cs(_, Some(_)) => {}
                 }
             }
@@ -227,14 +255,14 @@ mod tests {
             r#"
             enum A {
                 As,
-                Bs{x:i32, y:Option<i32>},
+                Bs { x: i32, y: Option<i32> },
                 Cs(i32, Option<i32>),
             }
             fn main() {
-                match <|>A::As {
-                    A::Bs{x,y:Some(_)} => {}
+                match A::As {
+                    A::Bs { x, y: Some(_) } => {}
                     A::Cs(_, Some(_)) => {}
-                    A::As => {}
+                    $0A::As => {}
                 }
             }
             "#,
@@ -264,9 +292,9 @@ mod tests {
                 Cs(Option<i32>),
             }
             fn main() {
-                match <|>A::As {
+                match A::As {
                     A::Cs(_) | A::Bs => {}
-                    A::As => {}
+                    $0A::As => {}
                 }
             }
             "#,
@@ -310,11 +338,11 @@ mod tests {
                 Ys,
             }
             fn main() {
-                match <|>A::As {
+                match A::As {
                     A::Bs if 0 < 1 => {}
                     A::Ds(_value) => { let x = 1; }
                     A::Es(B::Xs) => (),
-                    A::As => {}
+                    $0A::As => {}
                     A::Cs => {}
                 }
             }
@@ -332,7 +360,7 @@ mod tests {
                 Bs,
                 Cs(String),
                 Ds(String, String),
-                Es{ x: usize, y: usize }
+                Es { x: usize, y: usize }
             }
 
             fn main() {
@@ -346,13 +374,13 @@ mod tests {
                 Bs,
                 Cs(String),
                 Ds(String, String),
-                Es{ x: usize, y: usize }
+                Es { x: usize, y: usize }
             }
 
             fn main() {
                 let a = A::As;
-                match <|>a {
-                    A::As => {}
+                match a {
+                    $0A::As => {}
                     A::Bs => {}
                     A::Cs(_) => {}
                     A::Ds(_, _) => {}
@@ -368,14 +396,8 @@ mod tests {
         check_assist(
             fill_match_arms,
             r#"
-            enum A {
-                One,
-                Two,
-            }
-            enum B {
-                One,
-                Two,
-            }
+            enum A { One, Two }
+            enum B { One, Two }
 
             fn main() {
                 let a = A::One;
@@ -384,20 +406,14 @@ mod tests {
             }
             "#,
             r#"
-            enum A {
-                One,
-                Two,
-            }
-            enum B {
-                One,
-                Two,
-            }
+            enum A { One, Two }
+            enum B { One, Two }
 
             fn main() {
                 let a = A::One;
                 let b = B::One;
-                match <|>(a, b) {
-                    (A::One, B::One) => {}
+                match (a, b) {
+                    $0(A::One, B::One) => {}
                     (A::One, B::Two) => {}
                     (A::Two, B::One) => {}
                     (A::Two, B::Two) => {}
@@ -412,14 +428,8 @@ mod tests {
         check_assist(
             fill_match_arms,
             r#"
-            enum A {
-                One,
-                Two,
-            }
-            enum B {
-                One,
-                Two,
-            }
+            enum A { One, Two }
+            enum B { One, Two }
 
             fn main() {
                 let a = A::One;
@@ -428,20 +438,14 @@ mod tests {
             }
             "#,
             r#"
-            enum A {
-                One,
-                Two,
-            }
-            enum B {
-                One,
-                Two,
-            }
+            enum A { One, Two }
+            enum B { One, Two }
 
             fn main() {
                 let a = A::One;
                 let b = B::One;
-                match <|>(&a, &b) {
-                    (A::One, B::One) => {}
+                match (&a, &b) {
+                    $0(A::One, B::One) => {}
                     (A::One, B::Two) => {}
                     (A::Two, B::One) => {}
                     (A::Two, B::Two) => {}
@@ -456,14 +460,8 @@ mod tests {
         check_assist_not_applicable(
             fill_match_arms,
             r#"
-            enum A {
-                One,
-                Two,
-            }
-            enum B {
-                One,
-                Two,
-            }
+            enum A { One, Two }
+            enum B { One, Two }
 
             fn main() {
                 let a = A::One;
@@ -481,14 +479,8 @@ mod tests {
         check_assist_not_applicable(
             fill_match_arms,
             r#"
-            enum A {
-                One,
-                Two,
-            }
-            enum B {
-                One,
-                Two,
-            }
+            enum A { One, Two }
+            enum B { One, Two }
 
             fn main() {
                 let a = A::One;
@@ -512,10 +504,7 @@ mod tests {
         check_assist_not_applicable(
             fill_match_arms,
             r#"
-            enum A {
-                One,
-                Two,
-            }
+            enum A { One, Two }
 
             fn main() {
                 let a = A::One;
@@ -531,9 +520,7 @@ mod tests {
         check_assist(
             fill_match_arms,
             r#"
-            enum A {
-                As,
-            }
+            enum A { As }
 
             fn foo(a: &A) {
                 match a<|> {
@@ -541,13 +528,11 @@ mod tests {
             }
             "#,
             r#"
-            enum A {
-                As,
-            }
+            enum A { As }
 
             fn foo(a: &A) {
-                match <|>a {
-                    A::As => {}
+                match a {
+                    $0A::As => {}
                 }
             }
             "#,
@@ -557,7 +542,7 @@ mod tests {
             fill_match_arms,
             r#"
             enum A {
-                Es{ x: usize, y: usize }
+                Es { x: usize, y: usize }
             }
 
             fn foo(a: &mut A) {
@@ -567,12 +552,12 @@ mod tests {
             "#,
             r#"
             enum A {
-                Es{ x: usize, y: usize }
+                Es { x: usize, y: usize }
             }
 
             fn foo(a: &mut A) {
-                match <|>a {
-                    A::Es { x, y } => {}
+                match a {
+                    $0A::Es { x, y } => {}
                 }
             }
             "#,
@@ -611,8 +596,8 @@ mod tests {
             enum E { X, Y }
 
             fn main() {
-                match <|>E::X {
-                    E::X => {}
+                match E::X {
+                    $0E::X => {}
                     E::Y => {}
                 }
             }
@@ -639,8 +624,8 @@ mod tests {
             use foo::E::X;
 
             fn main() {
-                match <|>X {
-                    X => {}
+                match X {
+                    $0X => {}
                     foo::E::Y => {}
                 }
             }
@@ -653,10 +638,7 @@ mod tests {
         check_assist(
             fill_match_arms,
             r#"
-            enum A {
-                One,
-                Two,
-            }
+            enum A { One, Two }
             fn foo(a: A) {
                 match a {
                     // foo bar baz<|>
@@ -666,16 +648,13 @@ mod tests {
             }
             "#,
             r#"
-            enum A {
-                One,
-                Two,
-            }
+            enum A { One, Two }
             fn foo(a: A) {
-                match <|>a {
+                match a {
                     // foo bar baz
                     A::One => {}
                     // This is where the rest should be
-                    A::Two => {}
+                    $0A::Two => {}
                 }
             }
             "#,
@@ -687,10 +666,7 @@ mod tests {
         check_assist(
             fill_match_arms,
             r#"
-            enum A {
-                One,
-                Two,
-            }
+            enum A { One, Two }
             fn foo(a: A) {
                 match a {
                     // foo bar baz<|>
@@ -698,14 +674,11 @@ mod tests {
             }
             "#,
             r#"
-            enum A {
-                One,
-                Two,
-            }
+            enum A { One, Two }
             fn foo(a: A) {
-                match <|>a {
+                match a {
                     // foo bar baz
-                    A::One => {}
+                    $0A::One => {}
                     A::Two => {}
                 }
             }
@@ -728,12 +701,37 @@ mod tests {
             r#"
             enum A { One, Two, }
             fn foo(a: A) {
-                match <|>a {
-                    A::One => {}
+                match a {
+                    $0A::One => {}
                     A::Two => {}
                 }
             }
             "#,
         );
     }
+
+    #[test]
+    fn option_order() {
+        mark::check!(option_order);
+        let before = r#"
+fn foo(opt: Option<i32>) {
+    match opt<|> {
+    }
+}"#;
+        let before =
+            &format!("//- main.rs crate:main deps:core\n{}{}", before, FamousDefs::FIXTURE);
+
+        check_assist(
+            fill_match_arms,
+            before,
+            r#"
+fn foo(opt: Option<i32>) {
+    match opt {
+        $0Some(_) => {}
+        None => {}
+    }
+}
+"#,
+        );
+    }
 }
diff --git a/crates/ra_assists/src/handlers/fix_visibility.rs b/crates/ra_assists/src/handlers/fix_visibility.rs
new file mode 100644
index 000000000..9ec42f568
--- /dev/null
+++ b/crates/ra_assists/src/handlers/fix_visibility.rs
@@ -0,0 +1,559 @@
+use hir::{db::HirDatabase, HasSource, HasVisibility, PathResolution};
+use ra_db::FileId;
+use ra_syntax::{
+    ast, AstNode,
+    SyntaxKind::{ATTR, COMMENT, WHITESPACE},
+    SyntaxNode, TextRange, TextSize,
+};
+
+use crate::{AssistContext, AssistId, 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<|>() {}
+// }
+// ```
+// ->
+// ```
+// 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, 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"), assist_label, target, |builder| {
+        builder.set_file(target_file);
+        match ctx.config.snippet_cap {
+            Some(cap) => builder.insert_snippet(cap, offset, format!("$0{} ", 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::RecordField = 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, target) = match in_file_source.value {
+        hir::FieldSource::Named(it) => {
+            let s = it.syntax();
+            (vis_offset(s), s.text_range())
+        }
+        hir::FieldSource::Pos(it) => {
+            let s = it.syntax();
+            (vis_offset(s), 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"), assist_label, target, |builder| {
+        builder.set_file(target_file);
+        match ctx.config.snippet_cap {
+            Some(cap) => builder.insert_snippet(cap, offset, format!("$0{} ", missing_visibility)),
+            None => builder.insert(offset, format!("{} ", missing_visibility)),
+        }
+    })
+}
+
+fn target_data_for_def(
+    db: &dyn HirDatabase,
+    def: hir::ModuleDef,
+) -> Option<(TextSize, TextRange, FileId, Option<hir::Name>)> {
+    fn offset_target_and_file_id<S, Ast>(
+        db: &dyn HirDatabase,
+        x: S,
+    ) -> (TextSize, TextRange, FileId)
+    where
+        S: HasSource<Ast = Ast>,
+        Ast: AstNode,
+    {
+        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;
+        (vis_offset(syntax), syntax.text_range(), file_id.original_file(db.upcast()))
+    }
+
+    let target_name;
+    let (offset, 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), syntax.text_range(), file_id)
+        }
+        // Enum variants can't be private, we can't modify builtin types
+        hir::ModuleDef::EnumVariant(_) | hir::ModuleDef::BuiltinType(_) => return None,
+    };
+
+    Some((offset, target, target_file, target_name))
+}
+
+fn vis_offset(node: &SyntaxNode) -> TextSize {
+    node.children_with_tokens()
+        .skip_while(|it| match it.kind() {
+            WHITESPACE | COMMENT | ATTR => true,
+            _ => false,
+        })
+        .next()
+        .map(|it| it.text_range().start())
+        .unwrap_or_else(|| node.text_range().start())
+}
+
+#[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<|>() } ",
+            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<|>() } ",
+        )
+    }
+
+    #[test]
+    fn fix_visibility_of_adt_in_submodule() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { struct Foo; }
+              fn main() { foo::Foo<|> } ",
+            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<|> } ",
+        );
+        check_assist(
+            fix_visibility,
+            r"mod foo { enum Foo; }
+              fn main() { foo::Foo<|> } ",
+            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<|> } ",
+        );
+        check_assist(
+            fix_visibility,
+            r"mod foo { union Foo; }
+              fn main() { foo::Foo<|> } ",
+            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<|> } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_adt_in_other_file() {
+        check_assist(
+            fix_visibility,
+            r"
+              //- /main.rs
+              mod foo;
+              fn main() { foo::Foo<|> }
+
+              //- /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 { <|>bar: () }; } ",
+            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 { <|>bar: () }; }
+              //- /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 { <|>bar: () }; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"//- /lib.rs
+              mod foo;
+              fn main() { foo::Foo { <|>bar: () }; }
+              //- /foo.rs
+              pub struct Foo { pub bar: () }
+              ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_enum_variant_field() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { pub enum Foo { Bar { bar: () } } }
+              fn main() { foo::Foo::Bar { <|>bar: () }; } ",
+            r"mod foo { pub enum Foo { Bar { $0pub(crate) bar: () } } }
+              fn main() { foo::Foo::Bar { bar: () }; } ",
+        );
+        check_assist(
+            fix_visibility,
+            r"//- /lib.rs
+              mod foo;
+              fn main() { foo::Foo::Bar { <|>bar: () }; }
+              //- /foo.rs
+              pub enum Foo { Bar { bar: () } }
+              ",
+            r"pub enum Foo { Bar { $0pub(crate) bar: () } }
+
+",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"mod foo { pub struct Foo { pub bar: (), } }
+              fn main() { foo::Foo { <|>bar: () }; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"//- /lib.rs
+              mod foo;
+              fn main() { foo::Foo { <|>bar: () }; }
+              //- /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 { <|>bar: () }; } ",
+            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 { <|>bar: () }; }
+              //- /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 { <|>bar: () }; } ",
+        );
+        check_assist_not_applicable(
+            fix_visibility,
+            r"//- /lib.rs
+              mod foo;
+              fn main() { foo::Foo { <|>bar: () }; }
+              //- /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<|> } ",
+            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<|> } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_static() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { static FOO: () = (); }
+              fn main() { foo::FOO<|> } ",
+            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<|> } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_trait() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { trait Foo { fn foo(&self) {} } }
+              fn main() { let x: &dyn foo::<|>Foo; } ",
+            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<|>; } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_type_alias() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { type Foo = (); }
+              fn main() { let x: foo::Foo<|>; } ",
+            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<|>; } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_module() {
+        check_assist(
+            fix_visibility,
+            r"mod foo { mod bar { fn bar() {} } }
+              fn main() { foo::bar<|>::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<|>::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<|>::bar(); } ",
+        );
+    }
+
+    #[test]
+    fn fix_visibility_of_inline_module_in_other_file() {
+        check_assist(
+            fix_visibility,
+            r"
+            //- /main.rs
+            mod foo;
+            fn main() { foo::bar<|>::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<|>>::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<|>
+              //- /lib.rs crate:foo
+              struct Bar;",
+            r"$0pub struct 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<|>
+            ",
+            r"
+            mod foo {
+                $0pub(crate) use bar::Baz;
+                mod bar { pub(super) struct Baz; }
+            }
+            foo::Baz
+            ",
+        )
+    }
+}
diff --git a/crates/ra_assists/src/handlers/flip_binexpr.rs b/crates/ra_assists/src/handlers/flip_binexpr.rs
index 692ba4895..573196576 100644
--- a/crates/ra_assists/src/handlers/flip_binexpr.rs
+++ b/crates/ra_assists/src/handlers/flip_binexpr.rs
@@ -85,17 +85,13 @@ mod tests {
         check_assist(
             flip_binexpr,
             "fn f() { let res = 1 ==<|> 2; }",
-            "fn f() { let res = 2 ==<|> 1; }",
+            "fn f() { let res = 2 == 1; }",
         )
     }
 
     #[test]
     fn flip_binexpr_works_for_gt() {
-        check_assist(
-            flip_binexpr,
-            "fn f() { let res = 1 ><|> 2; }",
-            "fn f() { let res = 2 <<|> 1; }",
-        )
+        check_assist(flip_binexpr, "fn f() { let res = 1 ><|> 2; }", "fn f() { let res = 2 < 1; }")
     }
 
     #[test]
@@ -103,7 +99,7 @@ mod tests {
         check_assist(
             flip_binexpr,
             "fn f() { let res = 1 <=<|> 2; }",
-            "fn f() { let res = 2 >=<|> 1; }",
+            "fn f() { let res = 2 >= 1; }",
         )
     }
 
@@ -112,7 +108,7 @@ mod tests {
         check_assist(
             flip_binexpr,
             "fn f() { let res = (1 + 1) ==<|> (2 + 2); }",
-            "fn f() { let res = (2 + 2) ==<|> (1 + 1); }",
+            "fn f() { let res = (2 + 2) == (1 + 1); }",
         )
     }
 
@@ -132,7 +128,7 @@ mod tests {
             fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
                 match other.downcast_ref::<Self>() {
                     None => false,
-                    Some(it) => self ==<|> it,
+                    Some(it) => self == it,
                 }
             }
             "#,
diff --git a/crates/ra_assists/src/handlers/flip_comma.rs b/crates/ra_assists/src/handlers/flip_comma.rs
index dfe2a7fed..a57a1c463 100644
--- a/crates/ra_assists/src/handlers/flip_comma.rs
+++ b/crates/ra_assists/src/handlers/flip_comma.rs
@@ -45,7 +45,7 @@ mod tests {
         check_assist(
             flip_comma,
             "fn foo(x: i32,<|> y: Result<(), ()>) {}",
-            "fn foo(y: Result<(), ()>,<|> x: i32) {}",
+            "fn foo(y: Result<(), ()>, x: i32) {}",
         )
     }
 
diff --git a/crates/ra_assists/src/handlers/flip_trait_bound.rs b/crates/ra_assists/src/handlers/flip_trait_bound.rs
index 8a08702ab..0115adc8b 100644
--- a/crates/ra_assists/src/handlers/flip_trait_bound.rs
+++ b/crates/ra_assists/src/handlers/flip_trait_bound.rs
@@ -60,7 +60,7 @@ mod tests {
         check_assist(
             flip_trait_bound,
             "struct S<T> where T: A <|>+ B { }",
-            "struct S<T> where T: B <|>+ A { }",
+            "struct S<T> where T: B + A { }",
         )
     }
 
@@ -69,13 +69,13 @@ mod tests {
         check_assist(
             flip_trait_bound,
             "impl X for S<T> where T: A +<|> B { }",
-            "impl X for S<T> where T: B +<|> A { }",
+            "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 <|>+ B>(t: T) { }", "fn f<T: B <|>+ A>(t: T) { }")
+        check_assist(flip_trait_bound, "fn f<T: A <|>+ B>(t: T) { }", "fn f<T: B + A>(t: T) { }")
     }
 
     #[test]
@@ -83,7 +83,7 @@ mod tests {
         check_assist(
             flip_trait_bound,
             "fn f<T>(t: T) where T: A +<|> B { }",
-            "fn f<T>(t: T) where T: B +<|> A { }",
+            "fn f<T>(t: T) where T: B + A { }",
         )
     }
 
@@ -92,7 +92,7 @@ mod tests {
         check_assist(
             flip_trait_bound,
             "fn f<T>(t: T) where T: A <|>+ 'static { }",
-            "fn f<T>(t: T) where T: 'static <|>+ A { }",
+            "fn f<T>(t: T) where T: 'static + A { }",
         )
     }
 
@@ -101,7 +101,7 @@ mod tests {
         check_assist(
             flip_trait_bound,
             "struct S<T> where T: A<T> <|>+ b_mod::B<T> + C<T> { }",
-            "struct S<T> where T: b_mod::B<T> <|>+ A<T> + C<T> { }",
+            "struct S<T> where T: b_mod::B<T> + A<T> + C<T> { }",
         )
     }
 
@@ -110,7 +110,7 @@ mod tests {
         check_assist(
             flip_trait_bound,
             "struct S<T> where T: A + B + C + D + E + F +<|> G + H + I + J { }",
-            "struct S<T> where T: A + B + C + D + E + G +<|> F + H + I + J { }",
+            "struct S<T> where T: A + B + C + D + E + G + F + H + I + J { }",
         )
     }
 }
diff --git a/crates/ra_assists/src/handlers/inline_local_variable.rs b/crates/ra_assists/src/handlers/inline_local_variable.rs
index 5b26814d3..d26e68847 100644
--- a/crates/ra_assists/src/handlers/inline_local_variable.rs
+++ b/crates/ra_assists/src/handlers/inline_local_variable.rs
@@ -3,7 +3,7 @@ use ra_syntax::{
     ast::{self, AstNode, AstToken},
     TextRange,
 };
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{
     assist_context::{AssistContext, Assists},
@@ -33,11 +33,11 @@ pub(crate) fn inline_local_variable(acc: &mut Assists, ctx: &AssistContext) -> O
         _ => return None,
     };
     if bind_pat.mut_token().is_some() {
-        tested_by!(test_not_inline_mut_variable);
+        mark::hit!(test_not_inline_mut_variable);
         return None;
     }
     if !bind_pat.syntax().text_range().contains_inclusive(ctx.offset()) {
-        tested_by!(not_applicable_outside_of_bind_pat);
+        mark::hit!(not_applicable_outside_of_bind_pat);
         return None;
     }
     let initializer_expr = let_stmt.initializer()?;
@@ -46,7 +46,7 @@ pub(crate) fn inline_local_variable(acc: &mut Assists, ctx: &AssistContext) -> O
     let def = Definition::Local(def);
     let refs = def.find_usages(ctx.db, None);
     if refs.is_empty() {
-        tested_by!(test_not_applicable_if_variable_unused);
+        mark::hit!(test_not_applicable_if_variable_unused);
         return None;
     };
 
@@ -116,13 +116,12 @@ pub(crate) fn inline_local_variable(acc: &mut Assists, ctx: &AssistContext) -> O
             let replacement = if should_wrap { init_in_paren.clone() } else { init_str.clone() };
             builder.replace(desc.file_range.range, replacement)
         }
-        builder.set_cursor(delete_range.start())
     })
 }
 
 #[cfg(test)]
 mod tests {
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::tests::{check_assist, check_assist_not_applicable};
 
@@ -149,7 +148,7 @@ fn foo() {
             r"
 fn bar(a: usize) {}
 fn foo() {
-    <|>1 + 1;
+    1 + 1;
     if 1 > 10 {
     }
 
@@ -183,7 +182,7 @@ fn foo() {
             r"
 fn bar(a: usize) {}
 fn foo() {
-    <|>(1 + 1) + 1;
+    (1 + 1) + 1;
     if (1 + 1) > 10 {
     }
 
@@ -217,7 +216,7 @@ fn foo() {
             r"
 fn bar(a: usize) {}
 fn foo() {
-    <|>bar(1) + 1;
+    bar(1) + 1;
     if bar(1) > 10 {
     }
 
@@ -251,7 +250,7 @@ fn foo() {
             r"
 fn bar(a: usize): usize { a }
 fn foo() {
-    <|>(bar(1) as u64) + 1;
+    (bar(1) as u64) + 1;
     if (bar(1) as u64) > 10 {
     }
 
@@ -283,7 +282,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>{ 10 + 1 } + 1;
+    { 10 + 1 } + 1;
     if { 10 + 1 } > 10 {
     }
 
@@ -315,7 +314,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>( 10 + 1 ) + 1;
+    ( 10 + 1 ) + 1;
     if ( 10 + 1 ) > 10 {
     }
 
@@ -330,7 +329,7 @@ fn foo() {
 
     #[test]
     fn test_not_inline_mut_variable() {
-        covers!(test_not_inline_mut_variable);
+        mark::check!(test_not_inline_mut_variable);
         check_assist_not_applicable(
             inline_local_variable,
             r"
@@ -353,7 +352,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>let b = bar(10 + 1) * 10;
+    let b = bar(10 + 1) * 10;
     let c = bar(10 + 1) as usize;
 }",
         );
@@ -373,7 +372,7 @@ fn foo() {
             r"
 fn foo() {
     let x = vec![1, 2, 3];
-    <|>let b = x[0] * 10;
+    let b = x[0] * 10;
     let c = x[0] as usize;
 }",
         );
@@ -393,7 +392,7 @@ fn foo() {
             r"
 fn foo() {
     let bar = vec![1];
-    <|>let b = bar.len() * 10;
+    let b = bar.len() * 10;
     let c = bar.len() as usize;
 }",
         );
@@ -421,7 +420,7 @@ struct Bar {
 
 fn foo() {
     let bar = Bar { foo: 1 };
-    <|>let b = bar.foo * 10;
+    let b = bar.foo * 10;
     let c = bar.foo as usize;
 }",
         );
@@ -442,7 +441,7 @@ fn foo() -> Option<usize> {
             r"
 fn foo() -> Option<usize> {
     let bar = Some(1);
-    <|>let b = bar? * 10;
+    let b = bar? * 10;
     let c = bar? as usize;
     None
 }",
@@ -462,7 +461,7 @@ fn foo() {
             r"
 fn foo() {
     let bar = 10;
-    <|>let b = &bar * 10;
+    let b = &bar * 10;
 }",
         );
     }
@@ -478,7 +477,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>let b = (10, 20)[0];
+    let b = (10, 20)[0];
 }",
         );
     }
@@ -494,7 +493,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>let b = [1, 2, 3].len();
+    let b = [1, 2, 3].len();
 }",
         );
     }
@@ -511,7 +510,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>let b = (10 + 20) * 10;
+    let b = (10 + 20) * 10;
     let c = (10 + 20) as usize;
 }",
         );
@@ -531,7 +530,7 @@ fn foo() {
             r"
 fn foo() {
     let d = 10;
-    <|>let b = d * 10;
+    let b = d * 10;
     let c = d as usize;
 }",
         );
@@ -549,7 +548,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>let b = { 10 } * 10;
+    let b = { 10 } * 10;
     let c = { 10 } as usize;
 }",
         );
@@ -569,7 +568,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>let b = (10 + 20) * 10;
+    let b = (10 + 20) * 10;
     let c = (10 + 20, 20);
     let d = [10 + 20, 10];
     let e = (10 + 20);
@@ -588,7 +587,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>for i in vec![10, 20] {}
+    for i in vec![10, 20] {}
 }",
         );
     }
@@ -604,7 +603,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>while 1 > 0 {}
+    while 1 > 0 {}
 }",
         );
     }
@@ -622,7 +621,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>loop {
+    loop {
         break 1 + 1;
     }
 }",
@@ -640,7 +639,7 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>return 1 > 0;
+    return 1 > 0;
 }",
         );
     }
@@ -656,14 +655,14 @@ fn foo() {
 }",
             r"
 fn foo() {
-    <|>match 1 > 0 {}
+    match 1 > 0 {}
 }",
         );
     }
 
     #[test]
     fn test_not_applicable_if_variable_unused() {
-        covers!(test_not_applicable_if_variable_unused);
+        mark::check!(test_not_applicable_if_variable_unused);
         check_assist_not_applicable(
             inline_local_variable,
             r"
@@ -676,7 +675,7 @@ fn foo() {
 
     #[test]
     fn not_applicable_outside_of_bind_pat() {
-        covers!(not_applicable_outside_of_bind_pat);
+        mark::check!(not_applicable_outside_of_bind_pat);
         check_assist_not_applicable(
             inline_local_variable,
             r"
diff --git a/crates/ra_assists/src/handlers/introduce_variable.rs b/crates/ra_assists/src/handlers/introduce_variable.rs
index fdf3ada0d..31d6539f7 100644
--- a/crates/ra_assists/src/handlers/introduce_variable.rs
+++ b/crates/ra_assists/src/handlers/introduce_variable.rs
@@ -4,10 +4,10 @@ use ra_syntax::{
         BLOCK_EXPR, BREAK_EXPR, COMMENT, LAMBDA_EXPR, LOOP_EXPR, MATCH_ARM, PATH_EXPR, RETURN_EXPR,
         WHITESPACE,
     },
-    SyntaxNode, TextSize,
+    SyntaxNode,
 };
 use stdx::format_to;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{AssistContext, AssistId, Assists};
 
@@ -23,7 +23,7 @@ use crate::{AssistContext, AssistId, Assists};
 // ->
 // ```
 // fn main() {
-//     let var_name = (1 + 2);
+//     let $0var_name = (1 + 2);
 //     var_name * 4;
 // }
 // ```
@@ -33,7 +33,7 @@ pub(crate) fn introduce_variable(acc: &mut Assists, ctx: &AssistContext) -> Opti
     }
     let node = ctx.covering_element();
     if node.kind() == COMMENT {
-        tested_by!(introduce_var_in_comment_is_not_applicable);
+        mark::hit!(introduce_var_in_comment_is_not_applicable);
         return None;
     }
     let expr = node.ancestors().find_map(valid_target_expr)?;
@@ -46,14 +46,13 @@ pub(crate) fn introduce_variable(acc: &mut Assists, ctx: &AssistContext) -> Opti
     acc.add(AssistId("introduce_variable"), "Extract into variable", target, move |edit| {
         let mut buf = String::new();
 
-        let cursor_offset = if wrap_in_block {
+        if wrap_in_block {
             buf.push_str("{ let var_name = ");
-            TextSize::of("{ let ")
         } else {
             buf.push_str("let var_name = ");
-            TextSize::of("let ")
         };
         format_to!(buf, "{}", expr.syntax());
+
         let full_stmt = ast::ExprStmt::cast(anchor_stmt.clone());
         let is_full_stmt = if let Some(expr_stmt) = &full_stmt {
             Some(expr.syntax().clone()) == expr_stmt.expr().map(|e| e.syntax().clone())
@@ -61,32 +60,47 @@ pub(crate) fn introduce_variable(acc: &mut Assists, ctx: &AssistContext) -> Opti
             false
         };
         if is_full_stmt {
-            tested_by!(test_introduce_var_expr_stmt);
+            mark::hit!(test_introduce_var_expr_stmt);
             if full_stmt.unwrap().semicolon_token().is_none() {
                 buf.push_str(";");
             }
-            edit.replace(expr.syntax().text_range(), buf);
-        } else {
-            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_str("\n");
-                buf.push_str(text.trim_start_matches('\n'));
-            } else {
-                buf.push_str(text);
+            let offset = expr.syntax().text_range();
+            match ctx.config.snippet_cap {
+                Some(cap) => {
+                    let snip = buf.replace("let var_name", "let $0var_name");
+                    edit.replace_snippet(cap, offset, snip)
+                }
+                None => edit.replace(offset, buf),
             }
+            return;
+        }
 
-            edit.replace(expr.syntax().text_range(), "var_name".to_string());
-            edit.insert(anchor_stmt.text_range().start(), buf);
-            if wrap_in_block {
-                edit.insert(anchor_stmt.text_range().end(), " }");
+        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_str("\n");
+            buf.push_str(text.trim_start_matches('\n'));
+        } else {
+            buf.push_str(text);
+        }
+
+        edit.replace(expr.syntax().text_range(), "var_name".to_string());
+        let offset = anchor_stmt.text_range().start();
+        match ctx.config.snippet_cap {
+            Some(cap) => {
+                let snip = buf.replace("let var_name", "let $0var_name");
+                edit.insert_snippet(cap, offset, snip)
             }
+            None => edit.insert(offset, buf),
+        }
+
+        if wrap_in_block {
+            edit.insert(anchor_stmt.text_range().end(), " }");
         }
-        edit.set_cursor(anchor_stmt.text_range().start() + cursor_offset);
     })
 }
 
@@ -113,7 +127,7 @@ fn anchor_stmt(expr: ast::Expr) -> Option<(SyntaxNode, bool)> {
     expr.syntax().ancestors().find_map(|node| {
         if let Some(expr) = node.parent().and_then(ast::BlockExpr::cast).and_then(|it| it.expr()) {
             if expr.syntax() == &node {
-                tested_by!(test_introduce_var_last_expr);
+                mark::hit!(test_introduce_var_last_expr);
                 return Some((node, false));
             }
         }
@@ -134,7 +148,7 @@ fn anchor_stmt(expr: ast::Expr) -> Option<(SyntaxNode, bool)> {
 
 #[cfg(test)]
 mod tests {
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
 
@@ -144,37 +158,37 @@ mod tests {
     fn test_introduce_var_simple() {
         check_assist(
             introduce_variable,
-            "
+            r#"
 fn foo() {
     foo(<|>1 + 1<|>);
-}",
-            "
+}"#,
+            r#"
 fn foo() {
-    let <|>var_name = 1 + 1;
+    let $0var_name = 1 + 1;
     foo(var_name);
-}",
+}"#,
         );
     }
 
     #[test]
     fn introduce_var_in_comment_is_not_applicable() {
-        covers!(introduce_var_in_comment_is_not_applicable);
+        mark::check!(introduce_var_in_comment_is_not_applicable);
         check_assist_not_applicable(introduce_variable, "fn main() { 1 + /* <|>comment<|> */ 1; }");
     }
 
     #[test]
     fn test_introduce_var_expr_stmt() {
-        covers!(test_introduce_var_expr_stmt);
+        mark::check!(test_introduce_var_expr_stmt);
         check_assist(
             introduce_variable,
-            "
+            r#"
 fn foo() {
     <|>1 + 1<|>;
-}",
-            "
+}"#,
+            r#"
 fn foo() {
-    let <|>var_name = 1 + 1;
-}",
+    let $0var_name = 1 + 1;
+}"#,
         );
         check_assist(
             introduce_variable,
@@ -185,7 +199,7 @@ fn foo() {
 }",
             "
 fn foo() {
-    let <|>var_name = { let x = 0; x };
+    let $0var_name = { let x = 0; x };
     something_else();
 }",
         );
@@ -201,7 +215,7 @@ fn foo() {
 }",
             "
 fn foo() {
-    let <|>var_name = 1;
+    let $0var_name = 1;
     var_name + 1;
 }",
         );
@@ -209,7 +223,7 @@ fn foo() {
 
     #[test]
     fn test_introduce_var_last_expr() {
-        covers!(test_introduce_var_last_expr);
+        mark::check!(test_introduce_var_last_expr);
         check_assist(
             introduce_variable,
             "
@@ -218,7 +232,7 @@ fn foo() {
 }",
             "
 fn foo() {
-    let <|>var_name = 1 + 1;
+    let $0var_name = 1 + 1;
     bar(var_name)
 }",
         );
@@ -230,7 +244,7 @@ fn foo() {
 }",
             "
 fn foo() {
-    let <|>var_name = bar(1 + 1);
+    let $0var_name = bar(1 + 1);
     var_name
 }",
         )
@@ -253,7 +267,7 @@ fn main() {
 fn main() {
     let x = true;
     let tuple = match x {
-        true => { let <|>var_name = 2 + 2; (var_name, true) }
+        true => { let $0var_name = 2 + 2; (var_name, true) }
         _ => (0, false)
     };
 }
@@ -283,7 +297,7 @@ fn main() {
     let tuple = match x {
         true => {
             let y = 1;
-            let <|>var_name = 2 + y;
+            let $0var_name = 2 + y;
             (var_name, true)
         }
         _ => (0, false)
@@ -304,7 +318,7 @@ fn main() {
 ",
             "
 fn main() {
-    let lambda = |x: u32| { let <|>var_name = x * 2; var_name };
+    let lambda = |x: u32| { let $0var_name = x * 2; var_name };
 }
 ",
         );
@@ -321,7 +335,7 @@ fn main() {
 ",
             "
 fn main() {
-    let lambda = |x: u32| { let <|>var_name = x * 2; var_name };
+    let lambda = |x: u32| { let $0var_name = x * 2; var_name };
 }
 ",
         );
@@ -338,7 +352,7 @@ fn main() {
 ",
             "
 fn main() {
-    let <|>var_name = Some(true);
+    let $0var_name = Some(true);
     let o = var_name;
 }
 ",
@@ -356,7 +370,7 @@ fn main() {
 ",
             "
 fn main() {
-    let <|>var_name = bar.foo();
+    let $0var_name = bar.foo();
     let v = var_name;
 }
 ",
@@ -374,7 +388,7 @@ fn foo() -> u32 {
 ",
             "
 fn foo() -> u32 {
-    let <|>var_name = 2 + 2;
+    let $0var_name = 2 + 2;
     return var_name;
 }
 ",
@@ -396,7 +410,7 @@ fn foo() -> u32 {
 fn foo() -> u32 {
 
 
-    let <|>var_name = 2 + 2;
+    let $0var_name = 2 + 2;
     return var_name;
 }
 ",
@@ -413,7 +427,7 @@ fn foo() -> u32 {
             "
 fn foo() -> u32 {
 
-        let <|>var_name = 2 + 2;
+        let $0var_name = 2 + 2;
         return var_name;
 }
 ",
@@ -438,7 +452,7 @@ fn foo() -> u32 {
     // bar
 
 
-    let <|>var_name = 2 + 2;
+    let $0var_name = 2 + 2;
     return var_name;
 }
 ",
@@ -459,7 +473,7 @@ fn main() {
             "
 fn main() {
     let result = loop {
-        let <|>var_name = 2 + 2;
+        let $0var_name = 2 + 2;
         break var_name;
     };
 }
@@ -478,7 +492,7 @@ fn main() {
 ",
             "
 fn main() {
-    let <|>var_name = 0f32 as u32;
+    let $0var_name = 0f32 as u32;
     let v = var_name;
 }
 ",
diff --git a/crates/ra_assists/src/handlers/invert_if.rs b/crates/ra_assists/src/handlers/invert_if.rs
index 527c7caef..59d278eb9 100644
--- a/crates/ra_assists/src/handlers/invert_if.rs
+++ b/crates/ra_assists/src/handlers/invert_if.rs
@@ -72,7 +72,7 @@ mod tests {
         check_assist(
             invert_if,
             "fn f() { i<|>f x != 3 { 1 } else { 3 + 2 } }",
-            "fn f() { i<|>f x == 3 { 3 + 2 } else { 1 } }",
+            "fn f() { if x == 3 { 3 + 2 } else { 1 } }",
         )
     }
 
@@ -81,7 +81,7 @@ mod tests {
         check_assist(
             invert_if,
             "fn f() { <|>if !cond { 3 * 2 } else { 1 } }",
-            "fn f() { <|>if cond { 1 } else { 3 * 2 } }",
+            "fn f() { if cond { 1 } else { 3 * 2 } }",
         )
     }
 
@@ -90,7 +90,7 @@ mod tests {
         check_assist(
             invert_if,
             "fn f() { i<|>f cond { 3 * 2 } else { 1 } }",
-            "fn f() { i<|>f !cond { 1 } else { 3 * 2 } }",
+            "fn f() { if !cond { 1 } else { 3 * 2 } }",
         )
     }
 
diff --git a/crates/ra_assists/src/handlers/merge_imports.rs b/crates/ra_assists/src/handlers/merge_imports.rs
index ac3e53c27..972d16241 100644
--- a/crates/ra_assists/src/handlers/merge_imports.rs
+++ b/crates/ra_assists/src/handlers/merge_imports.rs
@@ -58,8 +58,6 @@ pub(crate) fn merge_imports(acc: &mut Assists, ctx: &AssistContext) -> Option<()
     let target = tree.syntax().text_range();
     acc.add(AssistId("merge_imports"), "Merge imports", target, |builder| {
         builder.rewrite(rewriter);
-        // FIXME: we only need because our diff is imprecise
-        builder.set_cursor(offset);
     })
 }
 
@@ -142,7 +140,7 @@ use std::fmt<|>::Debug;
 use std::fmt::Display;
 ",
             r"
-use std::fmt<|>::{Debug, Display};
+use std::fmt::{Debug, Display};
 ",
         )
     }
@@ -156,7 +154,7 @@ use std::fmt::Debug;
 use std::fmt<|>::Display;
 ",
             r"
-use std::fmt:<|>:{Display, Debug};
+use std::fmt::{Display, Debug};
 ",
         );
     }
@@ -169,7 +167,7 @@ use std::fmt:<|>:{Display, Debug};
 use std::{fmt<|>::Debug, fmt::Display};
 ",
             r"
-use std::{fmt<|>::{Debug, Display}};
+use std::{fmt::{Debug, Display}};
 ",
         );
         check_assist(
@@ -178,7 +176,7 @@ use std::{fmt<|>::{Debug, Display}};
 use std::{fmt::Debug, fmt<|>::Display};
 ",
             r"
-use std::{fmt::<|>{Display, Debug}};
+use std::{fmt::{Display, Debug}};
 ",
         );
     }
@@ -192,7 +190,7 @@ use std<|>::cell::*;
 use std::str;
 ",
             r"
-use std<|>::{cell::*, str};
+use std::{cell::*, str};
 ",
         )
     }
@@ -206,7 +204,7 @@ use std<|>::cell::*;
 use std::str::*;
 ",
             r"
-use std<|>::{cell::*, str::*};
+use std::{cell::*, str::*};
 ",
         )
     }
@@ -222,7 +220,7 @@ use foo::baz;
 /// Doc comment
 ",
             r"
-use foo<|>::{bar, baz};
+use foo::{bar, baz};
 
 /// Doc comment
 ",
@@ -241,7 +239,7 @@ use {
 ",
             r"
 use {
-    foo<|>::{bar, baz},
+    foo::{bar, baz},
 };
 ",
         );
@@ -255,7 +253,7 @@ use {
 ",
             r"
 use {
-    foo::{bar<|>, baz},
+    foo::{bar, baz},
 };
 ",
         );
@@ -272,7 +270,7 @@ use foo::<|>{
 };
 ",
             r"
-use foo::{<|>
+use foo::{
     FooBar,
 bar::baz};
 ",
diff --git a/crates/ra_assists/src/handlers/merge_match_arms.rs b/crates/ra_assists/src/handlers/merge_match_arms.rs
index d4e38aa6a..ca04ec671 100644
--- a/crates/ra_assists/src/handlers/merge_match_arms.rs
+++ b/crates/ra_assists/src/handlers/merge_match_arms.rs
@@ -3,7 +3,7 @@ use std::iter::successors;
 use ra_syntax::{
     algo::neighbor,
     ast::{self, AstNode},
-    Direction, TextSize,
+    Direction,
 };
 
 use crate::{AssistContext, AssistId, Assists, TextRange};
@@ -41,17 +41,6 @@ pub(crate) fn merge_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option
     let current_expr = current_arm.expr()?;
     let current_text_range = current_arm.syntax().text_range();
 
-    enum CursorPos {
-        InExpr(TextSize),
-        InPat(TextSize),
-    }
-    let cursor_pos = ctx.offset();
-    let cursor_pos = if current_expr.syntax().text_range().contains(cursor_pos) {
-        CursorPos::InExpr(current_text_range.end() - cursor_pos)
-    } else {
-        CursorPos::InPat(cursor_pos)
-    };
-
     // 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))
@@ -87,10 +76,6 @@ pub(crate) fn merge_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option
         let start = arms_to_merge.first().unwrap().syntax().text_range().start();
         let end = arms_to_merge.last().unwrap().syntax().text_range().end();
 
-        edit.set_cursor(match cursor_pos {
-            CursorPos::InExpr(back_offset) => start + TextSize::of(&arm) - back_offset,
-            CursorPos::InPat(offset) => offset,
-        });
         edit.replace(TextRange::new(start, end), arm);
     })
 }
@@ -132,7 +117,7 @@ mod tests {
             fn main() {
                 let x = X::A;
                 let y = match x {
-                    X::A | X::B => { 1i32<|> }
+                    X::A | X::B => { 1i32 }
                     X::C => { 2i32 }
                 }
             }
@@ -164,7 +149,7 @@ mod tests {
             fn main() {
                 let x = X::A;
                 let y = match x {
-                    X::A | X::B | X::C | X::D => {<|> 1i32 },
+                    X::A | X::B | X::C | X::D => { 1i32 },
                     X::E => { 2i32 },
                 }
             }
@@ -197,7 +182,7 @@ mod tests {
                 let x = X::A;
                 let y = match x {
                     X::A => { 1i32 },
-                    _ => { 2i<|>32 }
+                    _ => { 2i32 }
                 }
             }
             "#,
@@ -226,7 +211,7 @@ mod tests {
 
             fn main() {
                 match X::A {
-                    X::A<|> | X::B | X::C => 92,
+                    X::A | X::B | X::C => 92,
                     X::D => 62,
                     _ => panic!(),
                 }
diff --git a/crates/ra_assists/src/handlers/move_bounds.rs b/crates/ra_assists/src/handlers/move_bounds.rs
index a41aacfc3..be2a7eddc 100644
--- a/crates/ra_assists/src/handlers/move_bounds.rs
+++ b/crates/ra_assists/src/handlers/move_bounds.rs
@@ -99,7 +99,7 @@ mod tests {
             fn foo<T: u32, <|>F: FnOnce(T) -> T>() {}
             "#,
             r#"
-            fn foo<T, <|>F>() where T: u32, F: FnOnce(T) -> T {}
+            fn foo<T, F>() where T: u32, F: FnOnce(T) -> T {}
             "#,
         );
     }
@@ -112,7 +112,7 @@ mod tests {
             impl<U: u32, <|>T> A<U, T> {}
             "#,
             r#"
-            impl<U, <|>T> A<U, T> where U: u32 {}
+            impl<U, T> A<U, T> where U: u32 {}
             "#,
         );
     }
@@ -125,7 +125,7 @@ mod tests {
             struct A<<|>T: Iterator<Item = u32>> {}
             "#,
             r#"
-            struct A<<|>T> where T: Iterator<Item = u32> {}
+            struct A<T> where T: Iterator<Item = u32> {}
             "#,
         );
     }
@@ -138,7 +138,7 @@ mod tests {
             struct Pair<<|>T: u32>(T, T);
             "#,
             r#"
-            struct Pair<<|>T>(T, T) where T: u32;
+            struct Pair<T>(T, T) where T: u32;
             "#,
         );
     }
diff --git a/crates/ra_assists/src/handlers/move_guard.rs b/crates/ra_assists/src/handlers/move_guard.rs
index fc0335b57..7edcf0748 100644
--- a/crates/ra_assists/src/handlers/move_guard.rs
+++ b/crates/ra_assists/src/handlers/move_guard.rs
@@ -1,7 +1,6 @@
 use ra_syntax::{
-    ast,
-    ast::{AstNode, AstToken, IfExpr, MatchArm},
-    TextSize,
+    ast::{AstNode, IfExpr, MatchArm},
+    SyntaxKind::WHITESPACE,
 };
 
 use crate::{AssistContext, AssistId, Assists};
@@ -42,24 +41,15 @@ pub(crate) fn move_guard_to_arm_body(acc: &mut Assists, ctx: &AssistContext) ->
 
     let target = guard.syntax().text_range();
     acc.add(AssistId("move_guard_to_arm_body"), "Move guard to arm body", target, |edit| {
-        let offseting_amount = match space_before_guard.and_then(|it| it.into_token()) {
-            Some(tok) => {
-                if ast::Whitespace::cast(tok.clone()).is_some() {
-                    let ele = tok.text_range();
-                    edit.delete(ele);
-                    ele.len()
-                } else {
-                    TextSize::from(0)
-                }
+        match space_before_guard {
+            Some(element) if element.kind() == WHITESPACE => {
+                edit.delete(element.text_range());
             }
-            _ => TextSize::from(0),
+            _ => (),
         };
 
         edit.delete(guard.syntax().text_range());
         edit.replace_node_and_indent(arm_expr.syntax(), buf);
-        edit.set_cursor(
-            arm_expr.syntax().text_range().start() + TextSize::from(3) - offseting_amount,
-        );
     })
 }
 
@@ -124,7 +114,6 @@ pub(crate) fn move_arm_cond_to_match_guard(acc: &mut Assists, ctx: &AssistContex
             }
 
             edit.insert(match_pat.syntax().text_range().end(), buf);
-            edit.set_cursor(match_pat.syntax().text_range().end() + TextSize::from(1));
         },
     )
 }
@@ -172,7 +161,7 @@ mod tests {
                 let t = 'a';
                 let chars = "abcd";
                 match t {
-                    '\r' => if chars.clone().next() == Some('\n') { <|>false },
+                    '\r' => if chars.clone().next() == Some('\n') { false },
                     _ => true
                 }
             }
@@ -195,7 +184,7 @@ mod tests {
             r#"
             fn f() {
                 match x {
-                    y @ 4 | y @ 5 => if y > 5 { <|>true },
+                    y @ 4 | y @ 5 => if y > 5 { true },
                     _ => false
                 }
             }
@@ -222,7 +211,7 @@ mod tests {
                 let t = 'a';
                 let chars = "abcd";
                 match t {
-                    '\r' <|>if chars.clone().next() == Some('\n') => false,
+                    '\r' if chars.clone().next() == Some('\n') => false,
                     _ => true
                 }
             }
@@ -266,7 +255,7 @@ mod tests {
                 let t = 'a';
                 let chars = "abcd";
                 match t {
-                    '\r' <|>if chars.clone().next().is_some() => {  },
+                    '\r' if chars.clone().next().is_some() => {  },
                     _ => true
                 }
             }
@@ -296,7 +285,7 @@ mod tests {
                 let mut t = 'a';
                 let chars = "abcd";
                 match t {
-                    '\r' <|>if chars.clone().next().is_some() => {
+                    '\r' if chars.clone().next().is_some() => {
                         t = 'e';
                         false
                     },
diff --git a/crates/ra_assists/src/handlers/raw_string.rs b/crates/ra_assists/src/handlers/raw_string.rs
index c20ffe0b3..16002d2ac 100644
--- a/crates/ra_assists/src/handlers/raw_string.rs
+++ b/crates/ra_assists/src/handlers/raw_string.rs
@@ -164,7 +164,7 @@ mod test {
             "#,
             r##"
             fn f() {
-                let s = <|>r#"random
+                let s = r#"random
 string"#;
             }
             "##,
@@ -182,7 +182,7 @@ string"#;
             "#,
             r##"
             fn f() {
-                format!(<|>r#"x = {}"#, 92)
+                format!(r#"x = {}"#, 92)
             }
             "##,
         )
@@ -199,7 +199,7 @@ string"#;
             "###,
             r####"
             fn f() {
-                let s = <|>r#"#random##
+                let s = r#"#random##
 string"#;
             }
             "####,
@@ -217,7 +217,7 @@ string"#;
             "###,
             r####"
             fn f() {
-                let s = <|>r###"#random"##
+                let s = r###"#random"##
 string"###;
             }
             "####,
@@ -235,7 +235,7 @@ string"###;
             "#,
             r##"
             fn f() {
-                let s = <|>r#"random string"#;
+                let s = r#"random string"#;
             }
             "##,
         )
@@ -289,7 +289,7 @@ string"###;
             "#,
             r##"
             fn f() {
-                let s = <|>r#"random string"#;
+                let s = r#"random string"#;
             }
             "##,
         )
@@ -306,7 +306,7 @@ string"###;
             "##,
             r###"
             fn f() {
-                let s = <|>r##"random"string"##;
+                let s = r##"random"string"##;
             }
             "###,
         )
@@ -348,7 +348,7 @@ string"###;
             "##,
             r#"
             fn f() {
-                let s = <|>r"random string";
+                let s = r"random string";
             }
             "#,
         )
@@ -365,7 +365,7 @@ string"###;
             "##,
             r#"
             fn f() {
-                let s = <|>r"random\"str\"ing";
+                let s = r"random\"str\"ing";
             }
             "#,
         )
@@ -382,7 +382,7 @@ string"###;
             "###,
             r##"
             fn f() {
-                let s = <|>r#"random string"#;
+                let s = r#"random string"#;
             }
             "##,
         )
@@ -436,7 +436,7 @@ string"###;
             "##,
             r#"
             fn f() {
-                let s = <|>"random string";
+                let s = "random string";
             }
             "#,
         )
@@ -453,7 +453,7 @@ string"###;
             "##,
             r#"
             fn f() {
-                let s = <|>"random\"str\"ing";
+                let s = "random\"str\"ing";
             }
             "#,
         )
@@ -470,7 +470,7 @@ string"###;
             "###,
             r##"
             fn f() {
-                let s = <|>"random string";
+                let s = "random string";
             }
             "##,
         )
diff --git a/crates/ra_assists/src/handlers/remove_dbg.rs b/crates/ra_assists/src/handlers/remove_dbg.rs
index 8eef578cf..961ee1731 100644
--- a/crates/ra_assists/src/handlers/remove_dbg.rs
+++ b/crates/ra_assists/src/handlers/remove_dbg.rs
@@ -29,26 +29,6 @@ pub(crate) fn remove_dbg(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
 
     let macro_range = macro_call.syntax().text_range();
 
-    // If the cursor is inside the macro call, we'll try to maintain the cursor
-    // position by subtracting the length of dbg!( from the start of the file
-    // range, otherwise we'll default to using the start of the macro call
-    let cursor_pos = {
-        let file_range = ctx.frange.range;
-
-        let offset_start = file_range
-            .start()
-            .checked_sub(macro_range.start())
-            .unwrap_or_else(|| TextSize::from(0));
-
-        let dbg_size = TextSize::of("dbg!(");
-
-        if offset_start > dbg_size {
-            file_range.start() - dbg_size
-        } else {
-            macro_range.start()
-        }
-    };
-
     let macro_content = {
         let macro_args = macro_call.token_tree()?.syntax().clone();
 
@@ -58,9 +38,8 @@ pub(crate) fn remove_dbg(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     };
 
     let target = macro_call.syntax().text_range();
-    acc.add(AssistId("remove_dbg"), "Remove dbg!()", target, |edit| {
-        edit.replace(macro_range, macro_content);
-        edit.set_cursor(cursor_pos);
+    acc.add(AssistId("remove_dbg"), "Remove dbg!()", target, |builder| {
+        builder.replace(macro_range, macro_content);
     })
 }
 
@@ -94,13 +73,13 @@ mod tests {
 
     #[test]
     fn test_remove_dbg() {
-        check_assist(remove_dbg, "<|>dbg!(1 + 1)", "<|>1 + 1");
+        check_assist(remove_dbg, "<|>dbg!(1 + 1)", "1 + 1");
 
-        check_assist(remove_dbg, "dbg!<|>((1 + 1))", "<|>(1 + 1)");
+        check_assist(remove_dbg, "dbg!<|>((1 + 1))", "(1 + 1)");
 
-        check_assist(remove_dbg, "dbg!(1 <|>+ 1)", "1 <|>+ 1");
+        check_assist(remove_dbg, "dbg!(1 <|>+ 1)", "1 + 1");
 
-        check_assist(remove_dbg, "let _ = <|>dbg!(1 + 1)", "let _ = <|>1 + 1");
+        check_assist(remove_dbg, "let _ = <|>dbg!(1 + 1)", "let _ = 1 + 1");
 
         check_assist(
             remove_dbg,
@@ -113,7 +92,7 @@ fn foo(n: usize) {
 ",
             "
 fn foo(n: usize) {
-    if let Some(_) = n.<|>checked_sub(4) {
+    if let Some(_) = n.checked_sub(4) {
         // ...
     }
 }
@@ -122,8 +101,8 @@ fn foo(n: usize) {
     }
     #[test]
     fn test_remove_dbg_with_brackets_and_braces() {
-        check_assist(remove_dbg, "dbg![<|>1 + 1]", "<|>1 + 1");
-        check_assist(remove_dbg, "dbg!{<|>1 + 1}", "<|>1 + 1");
+        check_assist(remove_dbg, "dbg![<|>1 + 1]", "1 + 1");
+        check_assist(remove_dbg, "dbg!{<|>1 + 1}", "1 + 1");
     }
 
     #[test]
diff --git a/crates/ra_assists/src/handlers/remove_mut.rs b/crates/ra_assists/src/handlers/remove_mut.rs
index dce546db7..fe4eada03 100644
--- a/crates/ra_assists/src/handlers/remove_mut.rs
+++ b/crates/ra_assists/src/handlers/remove_mut.rs
@@ -26,8 +26,7 @@ pub(crate) fn remove_mut(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     };
 
     let target = mut_token.text_range();
-    acc.add(AssistId("remove_mut"), "Remove `mut` keyword", target, |edit| {
-        edit.set_cursor(delete_from);
-        edit.delete(TextRange::new(delete_from, delete_to));
+    acc.add(AssistId("remove_mut"), "Remove `mut` keyword", target, |builder| {
+        builder.delete(TextRange::new(delete_from, delete_to));
     })
 }
diff --git a/crates/ra_assists/src/handlers/reorder_fields.rs b/crates/ra_assists/src/handlers/reorder_fields.rs
index 757f6406e..897da2832 100644
--- a/crates/ra_assists/src/handlers/reorder_fields.rs
+++ b/crates/ra_assists/src/handlers/reorder_fields.rs
@@ -23,7 +23,7 @@ use crate::{AssistContext, AssistId, Assists};
 // ```
 //
 pub(crate) fn reorder_fields(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    reorder::<ast::RecordLit>(acc, ctx.clone()).or_else(|| reorder::<ast::RecordPat>(acc, ctx))
+    reorder::<ast::RecordLit>(acc, ctx).or_else(|| reorder::<ast::RecordPat>(acc, ctx))
 }
 
 fn reorder<R: AstNode>(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
@@ -140,7 +140,7 @@ mod tests {
         "#,
             r#"
         struct Foo {foo: i32, bar: i32};
-        const test: Foo = <|>Foo {foo: 1, bar: 0}
+        const test: Foo = Foo {foo: 1, bar: 0}
         "#,
         )
     }
@@ -164,7 +164,7 @@ mod tests {
 
         fn f(f: Foo) -> {
             match f {
-                <|>Foo { ref mut bar, baz: 0, .. } => (),
+                Foo { ref mut bar, baz: 0, .. } => (),
                 _ => ()
             }
         }
@@ -202,7 +202,7 @@ mod tests {
             impl Foo {
                 fn new() -> Foo {
                     let foo = String::new();
-                    <|>Foo {
+                    Foo {
                         foo,
                         bar: foo.clone(),
                         extra: "Extra field",
diff --git a/crates/ra_assists/src/handlers/replace_if_let_with_match.rs b/crates/ra_assists/src/handlers/replace_if_let_with_match.rs
index 65f5fc6ab..e016f51c3 100644
--- a/crates/ra_assists/src/handlers/replace_if_let_with_match.rs
+++ b/crates/ra_assists/src/handlers/replace_if_let_with_match.rs
@@ -68,7 +68,6 @@ pub(crate) fn replace_if_let_with_match(acc: &mut Assists, ctx: &AssistContext)
                 .indent(IndentLevel::from_node(if_expr.syntax()))
         };
 
-        edit.set_cursor(if_expr.syntax().text_range().start());
         edit.replace_ast::<ast::Expr>(if_expr.into(), match_expr);
     })
 }
@@ -83,7 +82,7 @@ mod tests {
     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 <|>let VariantData::Struct(..) = *self {
@@ -92,16 +91,16 @@ impl VariantData {
             false
         }
     }
-}           ",
-            "
+}           "#,
+            r#"
 impl VariantData {
     pub fn is_struct(&self) -> bool {
-        <|>match *self {
+        match *self {
             VariantData::Struct(..) => true,
             _ => false,
         }
     }
-}           ",
+}           "#,
         )
     }
 
@@ -109,7 +108,7 @@ impl VariantData {
     fn test_replace_if_let_with_match_doesnt_unwrap_multiline_expressions() {
         check_assist(
             replace_if_let_with_match,
-            "
+            r#"
 fn foo() {
     if <|>let VariantData::Struct(..) = a {
         bar(
@@ -118,10 +117,10 @@ fn foo() {
     } else {
         false
     }
-}           ",
-            "
+}           "#,
+            r#"
 fn foo() {
-    <|>match a {
+    match a {
         VariantData::Struct(..) => {
             bar(
                 123
@@ -129,7 +128,7 @@ fn foo() {
         }
         _ => false,
     }
-}           ",
+}           "#,
         )
     }
 
@@ -137,7 +136,7 @@ fn foo() {
     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 <|>let VariantData::Struct(..) = *self {
@@ -146,7 +145,7 @@ impl VariantData {
             false
         }
     }
-}           ",
+}           "#,
             "if let VariantData::Struct(..) = *self {
             true
         } else {
@@ -176,7 +175,7 @@ enum Option<T> { Some(T), None }
 use Option::*;
 
 fn foo(x: Option<i32>) {
-    <|>match x {
+    match x {
         Some(x) => println!("{}", x),
         None => println!("none"),
     }
@@ -206,7 +205,7 @@ enum Result<T, E> { Ok(T), Err(E) }
 use Result::*;
 
 fn foo(x: Result<i32, ()>) {
-    <|>match x {
+    match x {
         Ok(x) => println!("{}", x),
         Err(_) => println!("none"),
     }
diff --git a/crates/ra_assists/src/handlers/replace_let_with_if_let.rs b/crates/ra_assists/src/handlers/replace_let_with_if_let.rs
index 482957dc6..761557ac0 100644
--- a/crates/ra_assists/src/handlers/replace_let_with_if_let.rs
+++ b/crates/ra_assists/src/handlers/replace_let_with_if_let.rs
@@ -58,12 +58,9 @@ pub(crate) fn replace_let_with_if_let(acc: &mut Assists, ctx: &AssistContext) ->
         let stmt = make::expr_stmt(if_);
 
         let placeholder = stmt.syntax().descendants().find_map(ast::PlaceholderPat::cast).unwrap();
-        let target_offset =
-            let_stmt.syntax().text_range().start() + placeholder.syntax().text_range().start();
         let stmt = stmt.replace_descendant(placeholder.into(), original_pat);
 
         edit.replace_ast(ast::Stmt::from(let_stmt), ast::Stmt::from(stmt));
-        edit.set_cursor(target_offset);
     })
 }
 
@@ -88,7 +85,7 @@ fn main() {
 enum E<T> { X(T), Y(T) }
 
 fn main() {
-    if let <|>x = E::X(92) {
+    if let x = E::X(92) {
     }
 }
             ",
diff --git a/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs b/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
index 1a81d8a0e..0197a8cf0 100644
--- a/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
+++ b/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
@@ -39,7 +39,7 @@ pub(crate) fn replace_qualified_name_with_use(
         target,
         |builder| {
             let path_to_import = hir_path.mod_path().clone();
-            insert_use_statement(path.syntax(), &path_to_import, ctx, builder);
+            insert_use_statement(path.syntax(), &path_to_import, ctx, builder.text_edit_builder());
 
             if let Some(last) = path.segment() {
                 // Here we are assuming the assist will provide a correct use statement
@@ -89,7 +89,7 @@ std::fmt::Debug<|>
             "
 use std::fmt::Debug;
 
-Debug<|>
+Debug
     ",
         );
     }
@@ -106,7 +106,7 @@ fn main() {
             "
 use std::fmt::Debug;
 
-Debug<|>
+Debug
 
 fn main() {
 }
@@ -130,7 +130,7 @@ use std::fmt::Debug;
 fn main() {
 }
 
-Debug<|>
+Debug
     ",
         );
     }
@@ -145,7 +145,7 @@ std::fmt<|>::Debug
             "
 use std::fmt;
 
-fmt<|>::Debug
+fmt::Debug
     ",
         );
     }
@@ -164,7 +164,7 @@ impl std::fmt::Debug<|> for Foo {
 use stdx;
 use std::fmt::Debug;
 
-impl Debug<|> for Foo {
+impl Debug for Foo {
 }
     ",
         );
@@ -181,7 +181,7 @@ impl std::fmt::Debug<|> for Foo {
             "
 use std::fmt::Debug;
 
-impl Debug<|> for Foo {
+impl Debug for Foo {
 }
     ",
         );
@@ -198,7 +198,7 @@ impl Debug<|> for Foo {
             "
     use std::fmt::Debug;
 
-    impl Debug<|> for Foo {
+    impl Debug for Foo {
     }
     ",
         );
@@ -217,7 +217,7 @@ impl std::io<|> for Foo {
             "
 use std::{io, fmt};
 
-impl io<|> for Foo {
+impl io for Foo {
 }
     ",
         );
@@ -236,7 +236,7 @@ impl std::fmt::Debug<|> for Foo {
             "
 use std::fmt::{self, Debug, };
 
-impl Debug<|> for Foo {
+impl Debug for Foo {
 }
     ",
         );
@@ -255,7 +255,7 @@ impl std::fmt<|> for Foo {
             "
 use std::fmt::{self, Debug};
 
-impl fmt<|> for Foo {
+impl fmt for Foo {
 }
     ",
         );
@@ -274,7 +274,7 @@ impl std::fmt::nested<|> for Foo {
             "
 use std::fmt::{Debug, nested::{Display, self}};
 
-impl nested<|> for Foo {
+impl nested for Foo {
 }
 ",
         );
@@ -293,7 +293,7 @@ impl std::fmt::nested<|> for Foo {
             "
 use std::fmt::{Debug, nested::{self, Display}};
 
-impl nested<|> for Foo {
+impl nested for Foo {
 }
 ",
         );
@@ -312,7 +312,7 @@ impl std::fmt::nested::Debug<|> for Foo {
             "
 use std::fmt::{Debug, nested::{Display, Debug}};
 
-impl Debug<|> for Foo {
+impl Debug for Foo {
 }
 ",
         );
@@ -331,7 +331,7 @@ impl std::fmt::nested::Display<|> for Foo {
             "
 use std::fmt::{nested::Display, Debug};
 
-impl Display<|> for Foo {
+impl Display for Foo {
 }
 ",
         );
@@ -350,7 +350,7 @@ impl std::fmt::Display<|> for Foo {
             "
 use std::fmt::{Display, nested::Debug};
 
-impl Display<|> for Foo {
+impl Display for Foo {
 }
 ",
         );
@@ -374,7 +374,7 @@ use crate::{
     AssocItem,
 };
 
-fn foo() { lower<|>::trait_env() }
+fn foo() { lower::trait_env() }
 ",
         );
     }
@@ -392,7 +392,7 @@ impl foo::Debug<|> for Foo {
             "
 use std::fmt as foo;
 
-impl Debug<|> for Foo {
+impl Debug for Foo {
 }
 ",
         );
@@ -435,7 +435,7 @@ mod foo {
     mod bar {
         use std::fmt::Debug;
 
-        Debug<|>
+        Debug
     }
 }
     ",
@@ -458,7 +458,7 @@ fn main() {
 use std::fmt::Debug;
 
 fn main() {
-    Debug<|>
+    Debug
 }
     ",
         );
diff --git a/crates/ra_assists/src/handlers/replace_unwrap_with_match.rs b/crates/ra_assists/src/handlers/replace_unwrap_with_match.rs
index c4b56f6e9..cff7dfb81 100644
--- a/crates/ra_assists/src/handlers/replace_unwrap_with_match.rs
+++ b/crates/ra_assists/src/handlers/replace_unwrap_with_match.rs
@@ -9,7 +9,10 @@ use ra_syntax::{
     AstNode,
 };
 
-use crate::{utils::TryEnum, AssistContext, AssistId, Assists};
+use crate::{
+    utils::{render_snippet, Cursor, TryEnum},
+    AssistContext, AssistId, Assists,
+};
 
 // Assist: replace_unwrap_with_match
 //
@@ -29,7 +32,7 @@ use crate::{utils::TryEnum, AssistContext, AssistId, Assists};
 //     let x: Result<i32, i32> = Result::Ok(92);
 //     let y = match x {
 //         Ok(a) => a,
-//         _ => unreachable!(),
+//         $0_ => unreachable!(),
 //     };
 // }
 // ```
@@ -43,7 +46,7 @@ pub(crate) fn replace_unwrap_with_match(acc: &mut Assists, ctx: &AssistContext)
     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"), "Replace unwrap with match", target, |edit| {
+    acc.add(AssistId("replace_unwrap_with_match"), "Replace unwrap with match", target, |builder| {
         let ok_path = make::path_unqualified(make::path_segment(make::name_ref(happy_variant)));
         let it = make::bind_pat(make::name("a")).into();
         let ok_tuple = make::tuple_struct_pat(ok_path, iter::once(it)).into();
@@ -51,23 +54,37 @@ pub(crate) fn replace_unwrap_with_match(acc: &mut Assists, ctx: &AssistContext)
         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::unreachable_macro_call().into();
+        let unreachable_call = make::expr_unreachable();
         let err_arm = make::match_arm(iter::once(make::placeholder_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()));
 
-        edit.set_cursor(caller.syntax().text_range().start());
-        edit.replace_ast::<ast::Expr>(method_call.into(), match_expr);
+        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 super::*;
     use crate::tests::{check_assist, check_assist_target};
 
+    use super::*;
+
     #[test]
     fn test_replace_result_unwrap_with_match() {
         check_assist(
@@ -85,9 +102,9 @@ 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) {
+    let y = match i(x) {
         Ok(a) => a,
-        _ => unreachable!(),
+        $0_ => unreachable!(),
     };
 }
             ",
@@ -111,9 +128,9 @@ 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) {
+    let y = match i(x) {
         Some(a) => a,
-        _ => unreachable!(),
+        $0_ => unreachable!(),
     };
 }
             ",
@@ -137,9 +154,9 @@ 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) {
+    let y = match i(x) {
         Ok(a) => a,
-        _ => unreachable!(),
+        $0_ => unreachable!(),
     }.count_zeroes();
 }
             ",
diff --git a/crates/ra_assists/src/handlers/split_import.rs b/crates/ra_assists/src/handlers/split_import.rs
index b2757e50c..c7a874480 100644
--- a/crates/ra_assists/src/handlers/split_import.rs
+++ b/crates/ra_assists/src/handlers/split_import.rs
@@ -26,12 +26,10 @@ pub(crate) fn split_import(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
     if new_tree == use_tree {
         return None;
     }
-    let cursor = ctx.offset();
 
     let target = colon_colon.text_range();
     acc.add(AssistId("split_import"), "Split import", target, |edit| {
         edit.replace_ast(use_tree, new_tree);
-        edit.set_cursor(cursor);
     })
 }
 
@@ -46,7 +44,7 @@ mod tests {
         check_assist(
             split_import,
             "use crate::<|>db::RootDatabase;",
-            "use crate::<|>{db::RootDatabase};",
+            "use crate::{db::RootDatabase};",
         )
     }
 
@@ -55,7 +53,7 @@ mod tests {
         check_assist(
             split_import,
             "use crate:<|>:db::{RootDatabase, FileSymbol}",
-            "use crate:<|>:{db::{RootDatabase, FileSymbol}}",
+            "use crate::{db::{RootDatabase, FileSymbol}}",
         )
     }
 
diff --git a/crates/ra_assists/src/handlers/unwrap_block.rs b/crates/ra_assists/src/handlers/unwrap_block.rs
index e52ec557e..8440c7d0f 100644
--- a/crates/ra_assists/src/handlers/unwrap_block.rs
+++ b/crates/ra_assists/src/handlers/unwrap_block.rs
@@ -1,8 +1,10 @@
-use crate::{AssistContext, AssistId, Assists};
-
-use ast::{ElseBranch, Expr, LoopBodyOwner};
 use ra_fmt::unwrap_trivial_block;
-use ra_syntax::{ast, match_ast, AstNode, TextRange, T};
+use ra_syntax::{
+    ast::{self, ElseBranch, Expr, LoopBodyOwner},
+    match_ast, AstNode, TextRange, T,
+};
+
+use crate::{AssistContext, AssistId, Assists};
 
 // Assist: unwrap_block
 //
@@ -60,7 +62,6 @@ pub(crate) fn unwrap_block(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
                             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.set_cursor(ancestor_then_branch.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(), &[' ', '{']));
@@ -77,7 +78,6 @@ pub(crate) fn unwrap_block(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
                                 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.set_cursor(then_branch.syntax().text_range().end());
                                     edit.delete(range_to_del);
                                     edit.replace(target, update_expr_string(else_block.to_string(), &[' ', '{']));
                                 });
@@ -95,8 +95,6 @@ pub(crate) fn unwrap_block(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
 
     let target = expr_to_unwrap.syntax().text_range();
     acc.add(assist_id, assist_label, target, |edit| {
-        edit.set_cursor(expr.syntax().text_range().start());
-
         edit.replace(
             expr.syntax().text_range(),
             update_expr_string(expr_to_unwrap.to_string(), &[' ', '{', '\n']),
@@ -152,7 +150,7 @@ mod tests {
             r#"
             fn main() {
                 bar();
-                <|>foo();
+                foo();
 
                 //comment
                 bar();
@@ -186,7 +184,7 @@ mod tests {
 
                     //comment
                     bar();
-                }<|>
+                }
                 println!("bar");
             }
             "#,
@@ -220,7 +218,7 @@ mod tests {
 
                     //comment
                     //bar();
-                }<|>
+                }
                 println!("bar");
             }
             "#,
@@ -256,7 +254,7 @@ mod tests {
                     //bar();
                 } else if false {
                     println!("bar");
-                }<|>
+                }
                 println!("foo");
             }
             "#,
@@ -296,7 +294,7 @@ mod tests {
                     println!("bar");
                 } else if true {
                     println!("foo");
-                }<|>
+                }
                 println!("else");
             }
             "#,
@@ -334,7 +332,7 @@ mod tests {
                     //bar();
                 } else if false {
                     println!("bar");
-                }<|>
+                }
                 println!("foo");
             }
             "#,
@@ -381,7 +379,7 @@ mod tests {
             "#,
             r#"
             fn main() {
-                <|>if true {
+                if true {
                     foo();
 
                     //comment
@@ -415,7 +413,7 @@ mod tests {
             r#"
             fn main() {
                 for i in 0..5 {
-                    <|>foo();
+                    foo();
 
                     //comment
                     bar();
@@ -445,7 +443,7 @@ mod tests {
             "#,
             r#"
             fn main() {
-                <|>if true {
+                if true {
                     foo();
 
                     //comment
@@ -478,7 +476,7 @@ mod tests {
             "#,
             r#"
             fn main() {
-                <|>if true {
+                if true {
                     foo();
 
                     //comment
diff --git a/crates/ra_assists/src/lib.rs b/crates/ra_assists/src/lib.rs
index b6dc7cb1b..464bc03dd 100644
--- a/crates/ra_assists/src/lib.rs
+++ b/crates/ra_assists/src/lib.rs
@@ -10,8 +10,8 @@ macro_rules! eprintln {
     ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
 }
 
+mod assist_config;
 mod assist_context;
-mod marks;
 #[cfg(test)]
 mod tests;
 pub mod utils;
@@ -24,6 +24,8 @@ use ra_syntax::TextRange;
 
 pub(crate) use crate::assist_context::{AssistContext, Assists};
 
+pub use assist_config::AssistConfig;
+
 /// Unique identifier of the assist, should not be shown to the user
 /// directly.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -54,9 +56,9 @@ impl Assist {
     ///
     /// Assists are returned in the "unresolved" state, that is only labels are
     /// returned, without actual edits.
-    pub fn unresolved(db: &RootDatabase, range: FileRange) -> Vec<Assist> {
+    pub fn unresolved(db: &RootDatabase, config: &AssistConfig, range: FileRange) -> Vec<Assist> {
         let sema = Semantics::new(db);
-        let ctx = AssistContext::new(sema, range);
+        let ctx = AssistContext::new(sema, config, range);
         let mut acc = Assists::new_unresolved(&ctx);
         handlers::all().iter().for_each(|handler| {
             handler(&mut acc, &ctx);
@@ -68,9 +70,13 @@ impl Assist {
     ///
     /// Assists are returned in the "resolved" state, that is with edit fully
     /// computed.
-    pub fn resolved(db: &RootDatabase, range: FileRange) -> Vec<ResolvedAssist> {
+    pub fn resolved(
+        db: &RootDatabase,
+        config: &AssistConfig,
+        range: FileRange,
+    ) -> Vec<ResolvedAssist> {
         let sema = Semantics::new(db);
-        let ctx = AssistContext::new(sema, range);
+        let ctx = AssistContext::new(sema, config, range);
         let mut acc = Assists::new_resolved(&ctx);
         handlers::all().iter().for_each(|handler| {
             handler(&mut acc, &ctx);
@@ -103,12 +109,14 @@ mod handlers {
     mod add_impl;
     mod add_missing_impl_members;
     mod add_new;
+    mod add_turbo_fish;
     mod apply_demorgan;
     mod auto_import;
     mod change_return_type_to_result;
     mod change_visibility;
     mod early_return;
     mod fill_match_arms;
+    mod fix_visibility;
     mod flip_binexpr;
     mod flip_comma;
     mod flip_trait_bound;
@@ -140,12 +148,14 @@ mod handlers {
             add_function::add_function,
             add_impl::add_impl,
             add_new::add_new,
+            add_turbo_fish::add_turbo_fish,
             apply_demorgan::apply_demorgan,
             auto_import::auto_import,
             change_return_type_to_result::change_return_type_to_result,
             change_visibility::change_visibility,
             early_return::convert_to_guarded_return,
             fill_match_arms::fill_match_arms,
+            fix_visibility::fix_visibility,
             flip_binexpr::flip_binexpr,
             flip_comma::flip_comma,
             flip_trait_bound::flip_trait_bound,
diff --git a/crates/ra_assists/src/marks.rs b/crates/ra_assists/src/marks.rs
deleted file mode 100644
index 8d910205f..000000000
--- a/crates/ra_assists/src/marks.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-//! See test_utils/src/marks.rs
-
-test_utils::marks![
-    introduce_var_in_comment_is_not_applicable
-    test_introduce_var_expr_stmt
-    test_introduce_var_last_expr
-    not_applicable_outside_of_bind_pat
-    test_not_inline_mut_variable
-    test_not_applicable_if_variable_unused
-    change_visibility_field_false_positive
-    test_add_from_impl_already_exists
-];
diff --git a/crates/ra_assists/src/tests.rs b/crates/ra_assists/src/tests.rs
index a3eacb8f1..62dd3547f 100644
--- a/crates/ra_assists/src/tests.rs
+++ b/crates/ra_assists/src/tests.rs
@@ -7,11 +7,10 @@ use ra_db::{fixture::WithFixture, FileId, FileRange, SourceDatabaseExt};
 use ra_ide_db::{symbol_index::SymbolsDatabase, RootDatabase};
 use ra_syntax::TextRange;
 use test_utils::{
-    add_cursor, assert_eq_text, extract_offset, extract_range, extract_range_or_offset,
-    RangeOrOffset,
+    assert_eq_text, extract_offset, extract_range, extract_range_or_offset, RangeOrOffset,
 };
 
-use crate::{handlers::Handler, Assist, AssistContext, Assists};
+use crate::{handlers::Handler, Assist, AssistConfig, AssistContext, Assists};
 
 pub(crate) fn with_single_file(text: &str) -> (RootDatabase, FileId) {
     let (mut db, file_id) = RootDatabase::with_single_file(text);
@@ -41,14 +40,14 @@ fn check_doc_test(assist_id: &str, before: &str, after: &str) {
     let (db, file_id) = crate::tests::with_single_file(&before);
     let frange = FileRange { file_id, range: selection.into() };
 
-    let mut assist = Assist::resolved(&db, frange)
+    let mut assist = Assist::resolved(&db, &AssistConfig::default(), frange)
         .into_iter()
         .find(|assist| assist.assist.id.0 == assist_id)
         .unwrap_or_else(|| {
             panic!(
                 "\n\nAssist is not applicable: {}\nAvailable assists: {}",
                 assist_id,
-                Assist::resolved(&db, frange)
+                Assist::resolved(&db, &AssistConfig::default(), frange)
                     .into_iter()
                     .map(|assist| assist.assist.id.0)
                     .collect::<Vec<_>>()
@@ -90,7 +89,8 @@ fn check(handler: Handler, before: &str, expected: ExpectedResult) {
     let frange = FileRange { file_id: file_with_caret_id, range: range_or_offset.into() };
 
     let sema = Semantics::new(&db);
-    let ctx = AssistContext::new(sema, frange);
+    let config = AssistConfig::default();
+    let ctx = AssistContext::new(sema, &config, frange);
     let mut acc = Assists::new_resolved(&ctx);
     handler(&mut acc, &ctx);
     let mut res = acc.finish_resolved();
@@ -102,20 +102,6 @@ fn check(handler: Handler, before: &str, expected: ExpectedResult) {
 
             let mut actual = db.file_text(change.file_id).as_ref().to_owned();
             change.edit.apply(&mut actual);
-
-            match source_change.cursor_position {
-                None => {
-                    if let RangeOrOffset::Offset(before_cursor_pos) = range_or_offset {
-                        let off = change
-                            .edit
-                            .apply_to_offset(before_cursor_pos)
-                            .expect("cursor position is affected by the edit");
-                        actual = add_cursor(&actual, off)
-                    }
-                }
-                Some(off) => actual = add_cursor(&actual, off.offset),
-            };
-
             assert_eq_text!(after, &actual);
         }
         (Some(assist), ExpectedResult::Target(target)) => {
@@ -136,7 +122,7 @@ fn assist_order_field_struct() {
     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::resolved(&db, frange);
+    let assists = Assist::resolved(&db, &AssistConfig::default(), frange);
     let mut assists = assists.iter();
 
     assert_eq!(
@@ -159,7 +145,7 @@ fn assist_order_if_expr() {
     let (range, before) = extract_range(before);
     let (db, file_id) = with_single_file(&before);
     let frange = FileRange { file_id, range };
-    let assists = Assist::resolved(&db, frange);
+    let assists = Assist::resolved(&db, &AssistConfig::default(), frange);
     let mut assists = assists.iter();
 
     assert_eq!(assists.next().expect("expected assist").assist.label, "Extract into variable");
diff --git a/crates/ra_assists/src/tests/generated.rs b/crates/ra_assists/src/tests/generated.rs
index 972dbd251..250e56a69 100644
--- a/crates/ra_assists/src/tests/generated.rs
+++ b/crates/ra_assists/src/tests/generated.rs
@@ -15,7 +15,7 @@ struct S;
 struct S;
 
 impl Debug for S {
-
+    $0
 }
 "#####,
     )
@@ -32,7 +32,7 @@ struct Point {
 }
 "#####,
         r#####"
-#[derive()]
+#[derive($0)]
 struct Point {
     x: u32,
     y: u32,
@@ -78,7 +78,7 @@ fn foo() {
 }
 
 fn bar(arg: &str, baz: Baz) {
-    todo!()
+    ${0:todo!()}
 }
 
 "#####,
@@ -108,16 +108,16 @@ fn doctest_add_impl() {
         "add_impl",
         r#####"
 struct Ctx<T: Clone> {
-     data: T,<|>
+    data: T,<|>
 }
 "#####,
         r#####"
 struct Ctx<T: Clone> {
-     data: T,
+    data: T,
 }
 
 impl<T: Clone> Ctx<T> {
-
+    $0
 }
 "#####,
     )
@@ -150,7 +150,7 @@ trait Trait {
 impl Trait for () {
     Type X = ();
     fn foo(&self) {}
-    fn bar(&self) {}
+    $0fn bar(&self) {}
 
 }
 "#####,
@@ -181,7 +181,7 @@ trait Trait<T> {
 
 impl Trait<u32> for () {
     fn foo(&self) -> u32 {
-        todo!()
+        ${0:todo!()}
     }
 
 }
@@ -204,7 +204,7 @@ struct Ctx<T: Clone> {
 }
 
 impl<T: Clone> Ctx<T> {
-    fn new(data: T) -> Self { Self { data } }
+    fn $0new(data: T) -> Self { Self { data } }
 }
 
 "#####,
@@ -212,6 +212,25 @@ impl<T: Clone> Ctx<T> {
 }
 
 #[test]
+fn doctest_add_turbo_fish() {
+    check_doc_test(
+        "add_turbo_fish",
+        r#####"
+fn make<T>() -> T { todo!() }
+fn main() {
+    let x = make<|>();
+}
+"#####,
+        r#####"
+fn make<T>() -> T { todo!() }
+fn main() {
+    let x = make::<${0:_}>();
+}
+"#####,
+    )
+}
+
+#[test]
 fn doctest_apply_demorgan() {
     check_doc_test(
         "apply_demorgan",
@@ -257,7 +276,7 @@ fn doctest_change_return_type_to_result() {
 fn foo() -> i32<|> { 42i32 }
 "#####,
         r#####"
-fn foo() -> Result<i32, > { Ok(42i32) }
+fn foo() -> Result<i32, ${0:_}> { Ok(42i32) }
 "#####,
     )
 }
@@ -317,7 +336,7 @@ enum Action { Move { distance: u32 }, Stop }
 
 fn handle(action: Action) {
     match action {
-        Action::Move { distance } => {}
+        $0Action::Move { distance } => {}
         Action::Stop => {}
     }
 }
@@ -326,6 +345,29 @@ fn handle(action: Action) {
 }
 
 #[test]
+fn doctest_fix_visibility() {
+    check_doc_test(
+        "fix_visibility",
+        r#####"
+mod m {
+    fn frobnicate() {}
+}
+fn main() {
+    m::frobnicate<|>() {}
+}
+"#####,
+        r#####"
+mod m {
+    $0pub(crate) fn frobnicate() {}
+}
+fn main() {
+    m::frobnicate() {}
+}
+"#####,
+    )
+}
+
+#[test]
 fn doctest_flip_binexpr() {
     check_doc_test(
         "flip_binexpr",
@@ -401,7 +443,7 @@ fn main() {
 "#####,
         r#####"
 fn main() {
-    let var_name = (1 + 2);
+    let $0var_name = (1 + 2);
     var_name * 4;
 }
 "#####,
@@ -722,7 +764,7 @@ fn main() {
     let x: Result<i32, i32> = Result::Ok(92);
     let y = match x {
         Ok(a) => a,
-        _ => unreachable!(),
+        $0_ => unreachable!(),
     };
 }
 "#####,
diff --git a/crates/ra_assists/src/utils.rs b/crates/ra_assists/src/utils.rs
index f3fc92ebf..0038a9764 100644
--- a/crates/ra_assists/src/utils.rs
+++ b/crates/ra_assists/src/utils.rs
@@ -1,18 +1,57 @@
 //! Assorted functions shared by several assists.
 pub(crate) mod insert_use;
 
-use std::iter;
+use std::{iter, ops};
 
-use hir::{Adt, Crate, Semantics, Trait, Type};
+use hir::{Adt, Crate, Enum, ScopeDef, Semantics, Trait, Type};
 use ra_ide_db::RootDatabase;
 use ra_syntax::{
     ast::{self, make, NameOwner},
-    AstNode, T,
+    AstNode, SyntaxNode, T,
 };
 use rustc_hash::FxHashSet;
 
+use crate::assist_config::SnippetCap;
+
 pub(crate) use insert_use::insert_use_statement;
 
+#[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 fn get_missing_assoc_items(
     sema: &Semantics<RootDatabase>,
     impl_def: &ast::ImplDef,
@@ -161,13 +200,19 @@ impl FamousDefs<'_, '_> {
     #[cfg(test)]
     pub(crate) const FIXTURE: &'static str = r#"
 //- /libcore.rs crate:core
-pub mod convert{
+pub mod convert {
     pub trait From<T> {
         fn from(T) -> Self;
     }
 }
 
-pub mod prelude { pub use crate::convert::From }
+pub mod option {
+    pub enum Option<T> { None, Some(T)}
+}
+
+pub mod prelude {
+    pub use crate::{convert::From, option::Option::{self, *}};
+}
 #[prelude_import]
 pub use prelude::*;
 "#;
@@ -176,7 +221,25 @@ pub use prelude::*;
         self.find_trait("core:convert:From")
     }
 
+    pub(crate) fn core_option_Option(&self) -> Option<Enum> {
+        self.find_enum("core:option:Option")
+    }
+
     fn find_trait(&self, path: &str) -> Option<Trait> {
+        match self.find_def(path)? {
+            hir::ScopeDef::ModuleDef(hir::ModuleDef::Trait(it)) => Some(it),
+            _ => None,
+        }
+    }
+
+    fn find_enum(&self, path: &str) -> Option<Enum> {
+        match self.find_def(path)? {
+            hir::ScopeDef::ModuleDef(hir::ModuleDef::Adt(hir::Adt::Enum(it))) => Some(it),
+            _ => None,
+        }
+    }
+
+    fn find_def(&self, path: &str) -> Option<ScopeDef> {
         let db = self.0.db;
         let mut path = path.split(':');
         let trait_ = path.next_back()?;
@@ -201,9 +264,6 @@ pub use prelude::*;
         }
         let def =
             module.scope(db, None).into_iter().find(|(name, _def)| &name.to_string() == trait_)?.1;
-        match def {
-            hir::ScopeDef::ModuleDef(hir::ModuleDef::Trait(it)) => Some(it),
-            _ => None,
-        }
+        Some(def)
     }
 }
diff --git a/crates/ra_assists/src/utils/insert_use.rs b/crates/ra_assists/src/utils/insert_use.rs
index 1214e3cd4..0ee43482f 100644
--- a/crates/ra_assists/src/utils/insert_use.rs
+++ b/crates/ra_assists/src/utils/insert_use.rs
@@ -11,7 +11,7 @@ use ra_syntax::{
 };
 use ra_text_edit::TextEditBuilder;
 
-use crate::assist_context::{AssistBuilder, AssistContext};
+use crate::assist_context::AssistContext;
 
 /// Creates and inserts a use statement for the given path to import.
 /// The use statement is inserted in the scope most appropriate to the
@@ -21,7 +21,7 @@ pub(crate) fn insert_use_statement(
     position: &SyntaxNode,
     path_to_import: &ModPath,
     ctx: &AssistContext,
-    builder: &mut AssistBuilder,
+    builder: &mut TextEditBuilder,
 ) {
     let target = path_to_import.to_string().split("::").map(SmolStr::new).collect::<Vec<_>>();
     let container = ctx.sema.ancestors_with_macros(position.clone()).find_map(|n| {
@@ -33,7 +33,7 @@ pub(crate) fn insert_use_statement(
 
     if let Some(container) = container {
         let action = best_action_for_target(container, position.clone(), &target);
-        make_assist(&action, &target, builder.text_edit_builder());
+        make_assist(&action, &target, builder);
     }
 }
 
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index c69e0efea..e08d62dd6 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -15,7 +15,7 @@ use ra_syntax::{
     },
     AstNode, AstPtr,
 };
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{
     adt::StructKind,
@@ -226,7 +226,7 @@ impl ExprCollector<'_> {
                         None => self.collect_expr_opt(condition.expr()),
                         // if let -- desugar to match
                         Some(pat) => {
-                            tested_by!(infer_resolve_while_let);
+                            mark::hit!(infer_resolve_while_let);
                             let pat = self.collect_pat(pat);
                             let match_expr = self.collect_expr_opt(condition.expr());
                             let placeholder_pat = self.missing_pat();
diff --git a/crates/ra_hir_def/src/body/scope.rs b/crates/ra_hir_def/src/body/scope.rs
index 86f953c80..09e92b74e 100644
--- a/crates/ra_hir_def/src/body/scope.rs
+++ b/crates/ra_hir_def/src/body/scope.rs
@@ -174,7 +174,7 @@ mod tests {
     use hir_expand::{name::AsName, InFile};
     use ra_db::{fixture::WithFixture, FileId, SourceDatabase};
     use ra_syntax::{algo::find_node_at_offset, ast, AstNode};
-    use test_utils::{assert_eq_text, covers, extract_offset};
+    use test_utils::{assert_eq_text, extract_offset, mark};
 
     use crate::{db::DefDatabase, test_db::TestDB, FunctionId, ModuleDefId};
 
@@ -388,7 +388,7 @@ mod tests {
 
     #[test]
     fn while_let_desugaring() {
-        covers!(infer_resolve_while_let);
+        mark::check!(infer_resolve_while_let);
         do_check_local_name(
             r#"
 fn test() {
diff --git a/crates/ra_hir_def/src/db.rs b/crates/ra_hir_def/src/db.rs
index 498a4c917..945a0025e 100644
--- a/crates/ra_hir_def/src/db.rs
+++ b/crates/ra_hir_def/src/db.rs
@@ -17,6 +17,7 @@ use crate::{
     item_scope::ItemInNs,
     lang_item::{LangItemTarget, LangItems},
     nameres::{raw::RawItems, CrateDefMap},
+    path::ModPath,
     visibility::Visibility,
     AttrDefId, ConstId, ConstLoc, DefWithBodyId, EnumId, EnumLoc, FunctionId, FunctionLoc,
     GenericDefId, ImplId, ImplLoc, ModuleId, StaticId, StaticLoc, StructId, StructLoc, TraitId,
@@ -112,12 +113,15 @@ pub trait DefDatabase: InternDatabase + AstDatabase + Upcast<dyn AstDatabase> {
     #[salsa::invoke(Documentation::documentation_query)]
     fn documentation(&self, def: AttrDefId) -> Option<Documentation>;
 
-    #[salsa::invoke(find_path::importable_locations_in_crate)]
+    #[salsa::invoke(find_path::importable_locations_of_query)]
     fn importable_locations_of(
         &self,
         item: ItemInNs,
         krate: CrateId,
     ) -> Arc<[(ModuleId, Name, Visibility)]>;
+
+    #[salsa::invoke(find_path::find_path_inner_query)]
+    fn find_path_inner(&self, item: ItemInNs, from: ModuleId, max_len: usize) -> Option<ModPath>;
 }
 
 fn crate_def_map_wait(db: &impl DefDatabase, krate: CrateId) -> Arc<CrateDefMap> {
diff --git a/crates/ra_hir_def/src/find_path.rs b/crates/ra_hir_def/src/find_path.rs
index 1ca20fabd..4db798473 100644
--- a/crates/ra_hir_def/src/find_path.rs
+++ b/crates/ra_hir_def/src/find_path.rs
@@ -1,5 +1,11 @@
 //! An algorithm to find a path to refer to a certain item.
 
+use std::sync::Arc;
+
+use hir_expand::name::{known, AsName, Name};
+use ra_prof::profile;
+use test_utils::mark;
+
 use crate::{
     db::DefDatabase,
     item_scope::ItemInNs,
@@ -7,26 +13,28 @@ use crate::{
     visibility::Visibility,
     CrateId, ModuleDefId, ModuleId,
 };
-use hir_expand::name::{known, AsName, Name};
-use std::sync::Arc;
-use test_utils::tested_by;
+
+// FIXME: handle local items
+
+/// Find a path that can be used to refer to a certain item. This can depend on
+/// *from where* you're referring to the item, hence the `from` parameter.
+pub fn find_path(db: &dyn DefDatabase, item: ItemInNs, from: ModuleId) -> Option<ModPath> {
+    let _p = profile("find_path");
+    db.find_path_inner(item, from, MAX_PATH_LEN)
+}
 
 const MAX_PATH_LEN: usize = 15;
 
 impl ModPath {
     fn starts_with_std(&self) -> bool {
-        self.segments.first().filter(|&first_segment| first_segment == &known::std).is_some()
+        self.segments.first() == Some(&known::std)
     }
 
     // When std library is present, paths starting with `std::`
     // should be preferred over paths starting with `core::` and `alloc::`
     fn can_start_with_std(&self) -> bool {
-        self.segments
-            .first()
-            .filter(|&first_segment| {
-                first_segment == &known::alloc || first_segment == &known::core
-            })
-            .is_some()
+        let first_segment = self.segments.first();
+        first_segment == Some(&known::alloc) || first_segment == Some(&known::core)
     }
 
     fn len(&self) -> usize {
@@ -41,16 +49,7 @@ impl ModPath {
     }
 }
 
-// FIXME: handle local items
-
-/// Find a path that can be used to refer to a certain item. This can depend on
-/// *from where* you're referring to the item, hence the `from` parameter.
-pub fn find_path(db: &dyn DefDatabase, item: ItemInNs, from: ModuleId) -> Option<ModPath> {
-    let _p = ra_prof::profile("find_path");
-    find_path_inner(db, item, from, MAX_PATH_LEN)
-}
-
-fn find_path_inner(
+pub(crate) fn find_path_inner_query(
     db: &dyn DefDatabase,
     item: ItemInNs,
     from: ModuleId,
@@ -141,8 +140,7 @@ fn find_path_inner(
     let mut best_path = None;
     let mut best_path_len = max_len;
     for (module_id, name) in importable_locations {
-        let mut path = match find_path_inner(
-            db,
+        let mut path = match db.find_path_inner(
             ItemInNs::Types(ModuleDefId::ModuleId(module_id)),
             from,
             best_path_len - 1,
@@ -165,17 +163,19 @@ fn find_path_inner(
 
 fn select_best_path(old_path: ModPath, new_path: ModPath, prefer_no_std: bool) -> ModPath {
     if old_path.starts_with_std() && new_path.can_start_with_std() {
-        tested_by!(prefer_std_paths);
         if prefer_no_std {
+            mark::hit!(prefer_no_std_paths);
             new_path
         } else {
+            mark::hit!(prefer_std_paths);
             old_path
         }
     } else if new_path.starts_with_std() && old_path.can_start_with_std() {
-        tested_by!(prefer_std_paths);
         if prefer_no_std {
+            mark::hit!(prefer_no_std_paths);
             old_path
         } else {
+            mark::hit!(prefer_std_paths);
             new_path
         }
     } else if new_path.len() < old_path.len() {
@@ -215,11 +215,12 @@ fn find_importable_locations(
 ///
 /// Note that the crate doesn't need to be the one in which the item is defined;
 /// it might be re-exported in other crates.
-pub(crate) fn importable_locations_in_crate(
+pub(crate) fn importable_locations_of_query(
     db: &dyn DefDatabase,
     item: ItemInNs,
     krate: CrateId,
 ) -> Arc<[(ModuleId, Name, Visibility)]> {
+    let _p = profile("importable_locations_of_query");
     let def_map = db.crate_def_map(krate);
     let mut result = Vec::new();
     for (local_id, data) in def_map.modules.iter() {
@@ -251,12 +252,14 @@ pub(crate) fn importable_locations_in_crate(
 
 #[cfg(test)]
 mod tests {
-    use super::*;
-    use crate::test_db::TestDB;
     use hir_expand::hygiene::Hygiene;
     use ra_db::fixture::WithFixture;
     use ra_syntax::ast::AstNode;
-    use test_utils::covers;
+    use test_utils::mark;
+
+    use crate::test_db::TestDB;
+
+    use super::*;
 
     /// `code` needs to contain a cursor marker; checks that `find_path` for the
     /// item the `path` refers to returns that same path when called from the
@@ -511,7 +514,7 @@ mod tests {
 
     #[test]
     fn prefer_std_paths_over_alloc() {
-        covers!(prefer_std_paths);
+        mark::check!(prefer_std_paths);
         let code = r#"
         //- /main.rs crate:main deps:alloc,std
         <|>
@@ -530,51 +533,50 @@ mod tests {
     }
 
     #[test]
-    fn prefer_alloc_paths_over_std() {
-        covers!(prefer_std_paths);
+    fn prefer_core_paths_over_std() {
+        mark::check!(prefer_no_std_paths);
         let code = r#"
-        //- /main.rs crate:main deps:alloc,std
+        //- /main.rs crate:main deps:core,std
         #![no_std]
 
         <|>
 
-        //- /std.rs crate:std deps:alloc
+        //- /std.rs crate:std deps:core
 
-        pub mod sync {
-            pub use alloc::sync::Arc;
+        pub mod fmt {
+            pub use core::fmt::Error;
         }
 
-        //- /zzz.rs crate:alloc
+        //- /zzz.rs crate:core
 
-        pub mod sync {
-            pub struct Arc;
+        pub mod fmt {
+            pub struct Error;
         }
         "#;
-        check_found_path(code, "alloc::sync::Arc");
+        check_found_path(code, "core::fmt::Error");
     }
 
     #[test]
-    fn prefer_core_paths_over_std() {
-        covers!(prefer_std_paths);
+    fn prefer_alloc_paths_over_std() {
         let code = r#"
-        //- /main.rs crate:main deps:core,std
+        //- /main.rs crate:main deps:alloc,std
         #![no_std]
 
         <|>
 
-        //- /std.rs crate:std deps:core
+        //- /std.rs crate:std deps:alloc
 
-        pub mod fmt {
-            pub use core::fmt::Error;
+        pub mod sync {
+            pub use alloc::sync::Arc;
         }
 
-        //- /zzz.rs crate:core
+        //- /zzz.rs crate:alloc
 
-        pub mod fmt {
-            pub struct Error;
+        pub mod sync {
+            pub struct Arc;
         }
         "#;
-        check_found_path(code, "core::fmt::Error");
+        check_found_path(code, "alloc::sync::Arc");
     }
 
     #[test]
diff --git a/crates/ra_hir_def/src/lang_item.rs b/crates/ra_hir_def/src/lang_item.rs
index d96ac8c0a..d962db3cc 100644
--- a/crates/ra_hir_def/src/lang_item.rs
+++ b/crates/ra_hir_def/src/lang_item.rs
@@ -73,8 +73,8 @@ pub struct LangItems {
 }
 
 impl LangItems {
-    pub fn target<'a>(&'a self, item: &str) -> Option<&'a LangItemTarget> {
-        self.items.get(item)
+    pub fn target(&self, item: &str) -> Option<LangItemTarget> {
+        self.items.get(item).copied()
     }
 
     /// Salsa query. This will look for lang items in a specific crate.
@@ -163,9 +163,13 @@ impl LangItems {
     ) where
         T: Into<AttrDefId> + Copy,
     {
-        let attrs = db.attrs(item.into());
-        if let Some(lang_item_name) = attrs.by_key("lang").string_value() {
+        if let Some(lang_item_name) = lang_attr(db, item) {
             self.items.entry(lang_item_name.clone()).or_insert_with(|| constructor(item));
         }
     }
 }
+
+pub fn lang_attr(db: &dyn DefDatabase, item: impl Into<AttrDefId> + Copy) -> Option<SmolStr> {
+    let attrs = db.attrs(item.into());
+    attrs.by_key("lang").string_value().cloned()
+}
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index 518772e8a..5325a2760 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -46,8 +46,6 @@ pub mod find_path;
 
 #[cfg(test)]
 mod test_db;
-#[cfg(test)]
-mod marks;
 
 use std::hash::Hash;
 
diff --git a/crates/ra_hir_def/src/marks.rs b/crates/ra_hir_def/src/marks.rs
deleted file mode 100644
index daa49d5f1..000000000
--- a/crates/ra_hir_def/src/marks.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-//! See test_utils/src/marks.rs
-
-test_utils::marks!(
-    bogus_paths
-    name_res_works_for_broken_modules
-    can_import_enum_variant
-    glob_enum
-    glob_enum_group
-    glob_across_crates
-    std_prelude
-    macro_rules_from_other_crates_are_visible_with_macro_use
-    prelude_is_macro_use
-    macro_dollar_crate_self
-    macro_dollar_crate_other
-    infer_resolve_while_let
-    prefer_std_paths
-);
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index db994122a..353a31ad4 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -14,7 +14,7 @@ use ra_cfg::CfgOptions;
 use ra_db::{CrateId, FileId, ProcMacroId};
 use ra_syntax::ast;
 use rustc_hash::FxHashMap;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{
     attr::Attrs,
@@ -302,7 +302,7 @@ impl DefCollector<'_> {
         );
 
         if let Some(ModuleDefId::ModuleId(m)) = res.take_types() {
-            tested_by!(macro_rules_from_other_crates_are_visible_with_macro_use);
+            mark::hit!(macro_rules_from_other_crates_are_visible_with_macro_use);
             self.import_all_macros_exported(current_module_id, m.krate);
         }
     }
@@ -412,10 +412,10 @@ impl DefCollector<'_> {
             match def.take_types() {
                 Some(ModuleDefId::ModuleId(m)) => {
                     if import.is_prelude {
-                        tested_by!(std_prelude);
+                        mark::hit!(std_prelude);
                         self.def_map.prelude = Some(m);
                     } else if m.krate != self.def_map.krate {
-                        tested_by!(glob_across_crates);
+                        mark::hit!(glob_across_crates);
                         // glob import from other crate => we can just import everything once
                         let item_map = self.db.crate_def_map(m.krate);
                         let scope = &item_map[m.local_id].scope;
@@ -461,7 +461,7 @@ impl DefCollector<'_> {
                     }
                 }
                 Some(ModuleDefId::AdtId(AdtId::EnumId(e))) => {
-                    tested_by!(glob_enum);
+                    mark::hit!(glob_enum);
                     // glob import from enum => just import all the variants
 
                     // XXX: urgh, so this works by accident! Here, we look at
@@ -510,7 +510,7 @@ impl DefCollector<'_> {
 
                     self.update(module_id, &[(name, def)], vis);
                 }
-                None => tested_by!(bogus_paths),
+                None => mark::hit!(bogus_paths),
             }
         }
     }
@@ -683,7 +683,7 @@ impl ModCollector<'_, '_> {
         // Prelude module is always considered to be `#[macro_use]`.
         if let Some(prelude_module) = self.def_collector.def_map.prelude {
             if prelude_module.krate != self.def_collector.def_map.krate {
-                tested_by!(prelude_is_macro_use);
+                mark::hit!(prelude_is_macro_use);
                 self.def_collector.import_all_macros_exported(self.module_id, prelude_module.krate);
             }
         }
diff --git a/crates/ra_hir_def/src/nameres/path_resolution.rs b/crates/ra_hir_def/src/nameres/path_resolution.rs
index 35a0a0c98..19692e70c 100644
--- a/crates/ra_hir_def/src/nameres/path_resolution.rs
+++ b/crates/ra_hir_def/src/nameres/path_resolution.rs
@@ -14,7 +14,7 @@ use std::iter::successors;
 
 use hir_expand::name::Name;
 use ra_db::Edition;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{
     db::DefDatabase,
@@ -108,7 +108,7 @@ impl CrateDefMap {
         let mut curr_per_ns: PerNs = match path.kind {
             PathKind::DollarCrate(krate) => {
                 if krate == self.krate {
-                    tested_by!(macro_dollar_crate_self);
+                    mark::hit!(macro_dollar_crate_self);
                     PerNs::types(
                         ModuleId { krate: self.krate, local_id: self.root }.into(),
                         Visibility::Public,
@@ -116,7 +116,7 @@ impl CrateDefMap {
                 } else {
                     let def_map = db.crate_def_map(krate);
                     let module = ModuleId { krate, local_id: def_map.root };
-                    tested_by!(macro_dollar_crate_other);
+                    mark::hit!(macro_dollar_crate_other);
                     PerNs::types(module.into(), Visibility::Public)
                 }
             }
@@ -221,7 +221,7 @@ impl CrateDefMap {
                 }
                 ModuleDefId::AdtId(AdtId::EnumId(e)) => {
                     // enum variant
-                    tested_by!(can_import_enum_variant);
+                    mark::hit!(can_import_enum_variant);
                     let enum_data = db.enum_data(e);
                     match enum_data.variant(&segment) {
                         Some(local_id) => {
diff --git a/crates/ra_hir_def/src/nameres/raw.rs b/crates/ra_hir_def/src/nameres/raw.rs
index f2716a295..4e628b14d 100644
--- a/crates/ra_hir_def/src/nameres/raw.rs
+++ b/crates/ra_hir_def/src/nameres/raw.rs
@@ -18,7 +18,7 @@ use ra_syntax::{
     ast::{self, AttrsOwner, NameOwner, VisibilityOwner},
     AstNode,
 };
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{
     attr::Attrs,
@@ -346,7 +346,7 @@ impl RawItemsCollector {
             self.push_item(current_module, attrs, RawItemKind::Module(item));
             return;
         }
-        tested_by!(name_res_works_for_broken_modules);
+        mark::hit!(name_res_works_for_broken_modules);
     }
 
     fn add_use_item(&mut self, current_module: Option<Idx<ModuleData>>, use_item: ast::UseItem) {
diff --git a/crates/ra_hir_def/src/nameres/tests.rs b/crates/ra_hir_def/src/nameres/tests.rs
index 1b66c1aac..05cd0297d 100644
--- a/crates/ra_hir_def/src/nameres/tests.rs
+++ b/crates/ra_hir_def/src/nameres/tests.rs
@@ -8,7 +8,7 @@ use std::sync::Arc;
 
 use insta::assert_snapshot;
 use ra_db::{fixture::WithFixture, SourceDatabase};
-use test_utils::covers;
+use test_utils::mark;
 
 use crate::{db::DefDatabase, nameres::*, test_db::TestDB};
 
@@ -132,7 +132,7 @@ fn crate_def_map_fn_mod_same_name() {
 
 #[test]
 fn bogus_paths() {
-    covers!(bogus_paths);
+    mark::check!(bogus_paths);
     let map = def_map(
         "
         //- /lib.rs
@@ -247,7 +247,7 @@ fn re_exports() {
 
 #[test]
 fn std_prelude() {
-    covers!(std_prelude);
+    mark::check!(std_prelude);
     let map = def_map(
         "
         //- /main.rs crate:main deps:test_crate
@@ -271,7 +271,7 @@ fn std_prelude() {
 
 #[test]
 fn can_import_enum_variant() {
-    covers!(can_import_enum_variant);
+    mark::check!(can_import_enum_variant);
     let map = def_map(
         "
         //- /lib.rs
diff --git a/crates/ra_hir_def/src/nameres/tests/globs.rs b/crates/ra_hir_def/src/nameres/tests/globs.rs
index ee8df3a26..2b12c0daa 100644
--- a/crates/ra_hir_def/src/nameres/tests/globs.rs
+++ b/crates/ra_hir_def/src/nameres/tests/globs.rs
@@ -152,7 +152,7 @@ fn glob_privacy_2() {
 
 #[test]
 fn glob_across_crates() {
-    covers!(glob_across_crates);
+    mark::check!(glob_across_crates);
     let map = def_map(
         r"
         //- /main.rs crate:main deps:test_crate
@@ -171,7 +171,6 @@ fn glob_across_crates() {
 
 #[test]
 fn glob_privacy_across_crates() {
-    covers!(glob_across_crates);
     let map = def_map(
         r"
         //- /main.rs crate:main deps:test_crate
@@ -191,7 +190,7 @@ fn glob_privacy_across_crates() {
 
 #[test]
 fn glob_enum() {
-    covers!(glob_enum);
+    mark::check!(glob_enum);
     let map = def_map(
         "
         //- /lib.rs
@@ -212,7 +211,7 @@ fn glob_enum() {
 
 #[test]
 fn glob_enum_group() {
-    covers!(glob_enum_group);
+    mark::check!(glob_enum_group);
     let map = def_map(
         r"
         //- /lib.rs
diff --git a/crates/ra_hir_def/src/nameres/tests/macros.rs b/crates/ra_hir_def/src/nameres/tests/macros.rs
index 40289e3ca..84480d9f6 100644
--- a/crates/ra_hir_def/src/nameres/tests/macros.rs
+++ b/crates/ra_hir_def/src/nameres/tests/macros.rs
@@ -212,7 +212,7 @@ fn unexpanded_macro_should_expand_by_fixedpoint_loop() {
 
 #[test]
 fn macro_rules_from_other_crates_are_visible_with_macro_use() {
-    covers!(macro_rules_from_other_crates_are_visible_with_macro_use);
+    mark::check!(macro_rules_from_other_crates_are_visible_with_macro_use);
     let map = def_map(
         "
         //- /main.rs crate:main deps:foo
@@ -262,7 +262,7 @@ fn macro_rules_from_other_crates_are_visible_with_macro_use() {
 
 #[test]
 fn prelude_is_macro_use() {
-    covers!(prelude_is_macro_use);
+    mark::check!(prelude_is_macro_use);
     let map = def_map(
         "
         //- /main.rs crate:main deps:foo
@@ -544,8 +544,7 @@ fn path_qualified_macros() {
 
 #[test]
 fn macro_dollar_crate_is_correct_in_item() {
-    covers!(macro_dollar_crate_self);
-    covers!(macro_dollar_crate_other);
+    mark::check!(macro_dollar_crate_self);
     let map = def_map(
         "
         //- /main.rs crate:main deps:foo
@@ -603,7 +602,7 @@ fn macro_dollar_crate_is_correct_in_item() {
 
 #[test]
 fn macro_dollar_crate_is_correct_in_indirect_deps() {
-    covers!(macro_dollar_crate_other);
+    mark::check!(macro_dollar_crate_other);
     // From std
     let map = def_map(
         r#"
diff --git a/crates/ra_hir_def/src/nameres/tests/mod_resolution.rs b/crates/ra_hir_def/src/nameres/tests/mod_resolution.rs
index 37fcdfb8c..b43b294ca 100644
--- a/crates/ra_hir_def/src/nameres/tests/mod_resolution.rs
+++ b/crates/ra_hir_def/src/nameres/tests/mod_resolution.rs
@@ -2,7 +2,7 @@ use super::*;
 
 #[test]
 fn name_res_works_for_broken_modules() {
-    covers!(name_res_works_for_broken_modules);
+    mark::check!(name_res_works_for_broken_modules);
     let map = def_map(
         r"
         //- /lib.rs
diff --git a/crates/ra_hir_def/src/path/lower/lower_use.rs b/crates/ra_hir_def/src/path/lower/lower_use.rs
index 5b6854b0f..7cc655487 100644
--- a/crates/ra_hir_def/src/path/lower/lower_use.rs
+++ b/crates/ra_hir_def/src/path/lower/lower_use.rs
@@ -6,7 +6,7 @@ use std::iter;
 use either::Either;
 use hir_expand::{hygiene::Hygiene, name::AsName};
 use ra_syntax::ast::{self, NameOwner};
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::path::{ImportAlias, ModPath, PathKind};
 
@@ -54,7 +54,7 @@ pub(crate) fn lower_use_tree(
         // FIXME: report errors somewhere
         // We get here if we do
         } else if is_glob {
-            tested_by!(glob_enum_group);
+            mark::hit!(glob_enum_group);
             if let Some(prefix) = prefix {
                 cb(prefix, &tree, is_glob, None)
             }
diff --git a/crates/ra_hir_ty/Cargo.toml b/crates/ra_hir_ty/Cargo.toml
index 5fc0ec5e3..b2de7fa34 100644
--- a/crates/ra_hir_ty/Cargo.toml
+++ b/crates/ra_hir_ty/Cargo.toml
@@ -27,9 +27,9 @@ test_utils = { path = "../test_utils" }
 
 scoped-tls = "1"
 
-chalk-solve =   { git = "https://github.com/rust-lang/chalk.git", rev = "3e9c2503ae9c5277c2acb74624dc267876dd89b3" }
-chalk-rust-ir = { git = "https://github.com/rust-lang/chalk.git", rev = "3e9c2503ae9c5277c2acb74624dc267876dd89b3" }
-chalk-ir =      { git = "https://github.com/rust-lang/chalk.git", rev = "3e9c2503ae9c5277c2acb74624dc267876dd89b3" }
+chalk-solve =   { git = "https://github.com/rust-lang/chalk.git", rev = "eaab84b394007d1bed15f5470409a6ea02900a96" }
+chalk-rust-ir = { git = "https://github.com/rust-lang/chalk.git", rev = "eaab84b394007d1bed15f5470409a6ea02900a96" }
+chalk-ir =      { git = "https://github.com/rust-lang/chalk.git", rev = "eaab84b394007d1bed15f5470409a6ea02900a96" }
 
 [dev-dependencies]
 insta = "0.16.0"
diff --git a/crates/ra_hir_ty/src/_match.rs b/crates/ra_hir_ty/src/_match.rs
index 149f65042..3e6e1e333 100644
--- a/crates/ra_hir_ty/src/_match.rs
+++ b/crates/ra_hir_ty/src/_match.rs
@@ -1946,6 +1946,23 @@ mod tests {
 
         check_no_diagnostic(content);
     }
+
+    #[test]
+    fn expr_diverges_missing_arm() {
+        let content = r"
+            enum Either {
+                A,
+                B,
+            }
+            fn test_fn() {
+                match loop {} {
+                    Either::A => (),
+                }
+            }
+        ";
+
+        check_no_diagnostic(content);
+    }
 }
 
 #[cfg(test)]
@@ -1998,26 +2015,6 @@ mod false_negatives {
     }
 
     #[test]
-    fn expr_diverges_missing_arm() {
-        let content = r"
-            enum Either {
-                A,
-                B,
-            }
-            fn test_fn() {
-                match loop {} {
-                    Either::A => (),
-                }
-            }
-        ";
-
-        // This is a false negative.
-        // Even though the match expression diverges, rustc fails
-        // to compile here since `Either::B` is missing.
-        check_no_diagnostic(content);
-    }
-
-    #[test]
     fn expr_loop_missing_arm() {
         let content = r"
             enum Either {
@@ -2035,7 +2032,7 @@ mod false_negatives {
         // We currently infer the type of `loop { break Foo::A }` to `!`, which
         // causes us to skip the diagnostic since `Either::A` doesn't type check
         // with `!`.
-        check_no_diagnostic(content);
+        check_diagnostic(content);
     }
 
     #[test]
diff --git a/crates/ra_hir_ty/src/db.rs b/crates/ra_hir_ty/src/db.rs
index fdb49560b..0a8bb24ac 100644
--- a/crates/ra_hir_ty/src/db.rs
+++ b/crates/ra_hir_ty/src/db.rs
@@ -76,6 +76,8 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::interned]
     fn intern_type_ctor(&self, type_ctor: TypeCtor) -> crate::TypeCtorId;
     #[salsa::interned]
+    fn intern_callable_def(&self, callable_def: CallableDef) -> crate::CallableDefId;
+    #[salsa::interned]
     fn intern_type_param_id(&self, param_id: TypeParamId) -> GlobalTypeParamId;
     #[salsa::interned]
     fn intern_chalk_impl(&self, impl_: Impl) -> crate::traits::GlobalImplId;
@@ -89,11 +91,14 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     fn trait_datum(&self, krate: CrateId, trait_id: chalk::TraitId) -> Arc<chalk::TraitDatum>;
 
     #[salsa::invoke(chalk::struct_datum_query)]
-    fn struct_datum(&self, krate: CrateId, struct_id: chalk::StructId) -> Arc<chalk::StructDatum>;
+    fn struct_datum(&self, krate: CrateId, struct_id: chalk::AdtId) -> Arc<chalk::StructDatum>;
 
     #[salsa::invoke(crate::traits::chalk::impl_datum_query)]
     fn impl_datum(&self, krate: CrateId, impl_id: chalk::ImplId) -> Arc<chalk::ImplDatum>;
 
+    #[salsa::invoke(crate::traits::chalk::fn_def_datum_query)]
+    fn fn_def_datum(&self, krate: CrateId, fn_def_id: chalk::FnDefId) -> Arc<chalk::FnDefDatum>;
+
     #[salsa::invoke(crate::traits::chalk::associated_ty_value_query)]
     fn associated_ty_value(
         &self,
diff --git a/crates/ra_hir_ty/src/infer.rs b/crates/ra_hir_ty/src/infer.rs
index 2876cb141..957d6e0b5 100644
--- a/crates/ra_hir_ty/src/infer.rs
+++ b/crates/ra_hir_ty/src/infer.rs
@@ -218,6 +218,7 @@ struct InferenceContext<'a> {
 #[derive(Clone, Debug)]
 struct BreakableContext {
     pub may_break: bool,
+    pub break_ty: Ty,
 }
 
 impl<'a> InferenceContext<'a> {
diff --git a/crates/ra_hir_ty/src/infer/coerce.rs b/crates/ra_hir_ty/src/infer/coerce.rs
index 173ec59ed..2ee9adb16 100644
--- a/crates/ra_hir_ty/src/infer/coerce.rs
+++ b/crates/ra_hir_ty/src/infer/coerce.rs
@@ -5,7 +5,7 @@
 //! See: https://doc.rust-lang.org/nomicon/coercions.html
 
 use hir_def::{lang_item::LangItemTarget, type_ref::Mutability};
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{autoderef, traits::Solution, Obligation, Substs, TraitRef, Ty, TypeCtor};
 
@@ -34,7 +34,7 @@ impl<'a> InferenceContext<'a> {
             ty1.clone()
         } else {
             if let (ty_app!(TypeCtor::FnDef(_)), ty_app!(TypeCtor::FnDef(_))) = (ty1, ty2) {
-                tested_by!(coerce_fn_reification);
+                mark::hit!(coerce_fn_reification);
                 // Special case: two function types. Try to coerce both to
                 // pointers to have a chance at getting a match. See
                 // https://github.com/rust-lang/rust/blob/7b805396bf46dce972692a6846ce2ad8481c5f85/src/librustc_typeck/check/coercion.rs#L877-L916
@@ -44,7 +44,7 @@ impl<'a> InferenceContext<'a> {
                 let ptr_ty2 = Ty::fn_ptr(sig2);
                 self.coerce_merge_branch(&ptr_ty1, &ptr_ty2)
             } else {
-                tested_by!(coerce_merge_fail_fallback);
+                mark::hit!(coerce_merge_fail_fallback);
                 // For incompatible types, we use the latter one as result
                 // to be better recovery for `if` without `else`.
                 ty2.clone()
diff --git a/crates/ra_hir_ty/src/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs
index 0b67d216a..b28724f0e 100644
--- a/crates/ra_hir_ty/src/infer/expr.rs
+++ b/crates/ra_hir_ty/src/infer/expr.rs
@@ -93,22 +93,25 @@ impl<'a> InferenceContext<'a> {
                 Ty::Unknown
             }
             Expr::Loop { body } => {
-                self.breakables.push(BreakableContext { may_break: false });
+                self.breakables.push(BreakableContext {
+                    may_break: false,
+                    break_ty: self.table.new_type_var(),
+                });
                 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
 
                 let ctxt = self.breakables.pop().expect("breakable stack broken");
                 if ctxt.may_break {
                     self.diverges = Diverges::Maybe;
                 }
-                // FIXME handle break with value
+
                 if ctxt.may_break {
-                    Ty::unit()
+                    ctxt.break_ty
                 } else {
                     Ty::simple(TypeCtor::Never)
                 }
             }
             Expr::While { condition, body } => {
-                self.breakables.push(BreakableContext { may_break: false });
+                self.breakables.push(BreakableContext { may_break: false, break_ty: Ty::Unknown });
                 // while let is desugared to a match loop, so this is always simple while
                 self.infer_expr(*condition, &Expectation::has_type(Ty::simple(TypeCtor::Bool)));
                 self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
@@ -120,7 +123,7 @@ impl<'a> InferenceContext<'a> {
             Expr::For { iterable, body, pat } => {
                 let iterable_ty = self.infer_expr(*iterable, &Expectation::none());
 
-                self.breakables.push(BreakableContext { may_break: false });
+                self.breakables.push(BreakableContext { may_break: false, break_ty: Ty::Unknown });
                 let pat_ty =
                     self.resolve_associated_type(iterable_ty, self.resolve_into_iter_item());
 
@@ -229,17 +232,29 @@ impl<'a> InferenceContext<'a> {
             }
             Expr::Continue => Ty::simple(TypeCtor::Never),
             Expr::Break { expr } => {
-                if let Some(expr) = expr {
-                    // FIXME handle break with value
-                    self.infer_expr(*expr, &Expectation::none());
-                }
+                let val_ty = if let Some(expr) = expr {
+                    self.infer_expr(*expr, &Expectation::none())
+                } else {
+                    Ty::unit()
+                };
+
+                let last_ty = if let Some(ctxt) = self.breakables.last() {
+                    ctxt.break_ty.clone()
+                } else {
+                    Ty::Unknown
+                };
+
+                let merged_type = self.coerce_merge_branch(&last_ty, &val_ty);
+
                 if let Some(ctxt) = self.breakables.last_mut() {
+                    ctxt.break_ty = merged_type;
                     ctxt.may_break = true;
                 } else {
                     self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
                         expr: tgt_expr,
                     });
                 }
+
                 Ty::simple(TypeCtor::Never)
             }
             Expr::Return { expr } => {
diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs
index 54ec870df..4006f595d 100644
--- a/crates/ra_hir_ty/src/infer/pat.rs
+++ b/crates/ra_hir_ty/src/infer/pat.rs
@@ -10,7 +10,7 @@ use hir_def::{
     FieldId,
 };
 use hir_expand::name::Name;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use super::{BindingMode, Expectation, InferenceContext};
 use crate::{utils::variant_data, Substs, Ty, TypeCtor};
@@ -111,7 +111,7 @@ impl<'a> InferenceContext<'a> {
                 }
             }
         } else if let Pat::Ref { .. } = &body[pat] {
-            tested_by!(match_ergonomics_ref);
+            mark::hit!(match_ergonomics_ref);
             // When you encounter a `&pat` pattern, reset to Move.
             // This is so that `w` is by value: `let (_, &w) = &(1, &2);`
             default_bm = BindingMode::Move;
diff --git a/crates/ra_hir_ty/src/infer/unify.rs b/crates/ra_hir_ty/src/infer/unify.rs
index ab0bc8b70..269495ca0 100644
--- a/crates/ra_hir_ty/src/infer/unify.rs
+++ b/crates/ra_hir_ty/src/infer/unify.rs
@@ -4,7 +4,7 @@ use std::borrow::Cow;
 
 use ena::unify::{InPlaceUnificationTable, NoError, UnifyKey, UnifyValue};
 
-use test_utils::tested_by;
+use test_utils::mark;
 
 use super::{InferenceContext, Obligation};
 use crate::{
@@ -313,7 +313,7 @@ impl InferenceTable {
         // more than once
         for i in 0..3 {
             if i > 0 {
-                tested_by!(type_var_resolves_to_int_var);
+                mark::hit!(type_var_resolves_to_int_var);
             }
             match &*ty {
                 Ty::Infer(tv) => {
@@ -342,7 +342,7 @@ impl InferenceTable {
             Ty::Infer(tv) => {
                 let inner = tv.to_inner();
                 if tv_stack.contains(&inner) {
-                    tested_by!(type_var_cycles_resolve_as_possible);
+                    mark::hit!(type_var_cycles_resolve_as_possible);
                     // recursive type
                     return tv.fallback_value();
                 }
@@ -369,7 +369,7 @@ impl InferenceTable {
             Ty::Infer(tv) => {
                 let inner = tv.to_inner();
                 if tv_stack.contains(&inner) {
-                    tested_by!(type_var_cycles_resolve_completely);
+                    mark::hit!(type_var_cycles_resolve_completely);
                     // recursive type
                     return tv.fallback_value();
                 }
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index daea02f88..93cb45a64 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -42,7 +42,6 @@ pub mod expr;
 mod tests;
 #[cfg(test)]
 mod test_db;
-mod marks;
 mod _match;
 
 use std::ops::Deref;
@@ -156,10 +155,16 @@ pub enum TypeCtor {
 /// This exists just for Chalk, because Chalk just has a single `StructId` where
 /// we have different kinds of ADTs, primitive types and special type
 /// constructors like tuples and function pointers.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Ord, PartialOrd)]
 pub struct TypeCtorId(salsa::InternId);
 impl_intern_key!(TypeCtorId);
 
+/// This exists just for Chalk, because Chalk just has a single `FnDefId` where
+/// we have different IDs for struct and enum variant constructors.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Ord, PartialOrd)]
+pub struct CallableDefId(salsa::InternId);
+impl_intern_key!(CallableDefId);
+
 impl TypeCtor {
     pub fn num_ty_params(self, db: &dyn HirDatabase) -> usize {
         match self {
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index 9ad6dbe07..35ac86a46 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -812,7 +812,7 @@ impl TraitEnvironment {
                 // add `Self: Trait<T1, T2, ...>` to the environment in trait
                 // function default implementations (and hypothetical code
                 // inside consts or type aliases)
-                test_utils::tested_by!(trait_self_implements_self);
+                test_utils::mark::hit!(trait_self_implements_self);
                 let substs = Substs::type_params(db, trait_id);
                 let trait_ref = TraitRef { trait_: trait_id, substs };
                 let pred = GenericPredicate::Implemented(trait_ref);
diff --git a/crates/ra_hir_ty/src/marks.rs b/crates/ra_hir_ty/src/marks.rs
deleted file mode 100644
index a39740143..000000000
--- a/crates/ra_hir_ty/src/marks.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-//! See test_utils/src/marks.rs
-
-test_utils::marks!(
-    type_var_cycles_resolve_completely
-    type_var_cycles_resolve_as_possible
-    type_var_resolves_to_int_var
-    impl_self_type_match_without_receiver
-    match_ergonomics_ref
-    coerce_merge_fail_fallback
-    coerce_fn_reification
-    trait_self_implements_self
-);
diff --git a/crates/ra_hir_ty/src/method_resolution.rs b/crates/ra_hir_ty/src/method_resolution.rs
index 0851e16a8..e19628fdf 100644
--- a/crates/ra_hir_ty/src/method_resolution.rs
+++ b/crates/ra_hir_ty/src/method_resolution.rs
@@ -469,7 +469,7 @@ fn iterate_inherent_methods<T>(
                 // already happens in `is_valid_candidate` above; if not, we
                 // check it here
                 if receiver_ty.is_none() && inherent_impl_substs(db, impl_def, self_ty).is_none() {
-                    test_utils::tested_by!(impl_self_type_match_without_receiver);
+                    test_utils::mark::hit!(impl_self_type_match_without_receiver);
                     continue;
                 }
                 if let Some(result) = callback(&self_ty.value, item) {
diff --git a/crates/ra_hir_ty/src/tests/coercion.rs b/crates/ra_hir_ty/src/tests/coercion.rs
index 6dc4b2cd1..2cc4f4bf9 100644
--- a/crates/ra_hir_ty/src/tests/coercion.rs
+++ b/crates/ra_hir_ty/src/tests/coercion.rs
@@ -1,6 +1,6 @@
 use super::infer_with_mismatches;
 use insta::assert_snapshot;
-use test_utils::covers;
+use test_utils::mark;
 
 // Infer with some common definitions and impls.
 fn infer(source: &str) -> String {
@@ -339,7 +339,7 @@ fn test(i: i32) {
 
 #[test]
 fn coerce_merge_one_by_one1() {
-    covers!(coerce_merge_fail_fallback);
+    mark::check!(coerce_merge_fail_fallback);
 
     assert_snapshot!(
         infer(r#"
@@ -547,7 +547,7 @@ fn test() {
 
 #[test]
 fn coerce_fn_items_in_match_arms() {
-    covers!(coerce_fn_reification);
+    mark::check!(coerce_fn_reification);
     assert_snapshot!(
         infer_with_mismatches(r#"
 fn foo1(x: u32) -> isize { 1 }
diff --git a/crates/ra_hir_ty/src/tests/method_resolution.rs b/crates/ra_hir_ty/src/tests/method_resolution.rs
index 9c2c9e1d2..558a70022 100644
--- a/crates/ra_hir_ty/src/tests/method_resolution.rs
+++ b/crates/ra_hir_ty/src/tests/method_resolution.rs
@@ -984,7 +984,7 @@ fn test() { S2.into()<|>; }
 
 #[test]
 fn method_resolution_overloaded_method() {
-    test_utils::covers!(impl_self_type_match_without_receiver);
+    test_utils::mark::check!(impl_self_type_match_without_receiver);
     let t = type_at(
         r#"
 //- main.rs
diff --git a/crates/ra_hir_ty/src/tests/patterns.rs b/crates/ra_hir_ty/src/tests/patterns.rs
index d83ff5e0e..0c5f972a2 100644
--- a/crates/ra_hir_ty/src/tests/patterns.rs
+++ b/crates/ra_hir_ty/src/tests/patterns.rs
@@ -1,5 +1,5 @@
 use insta::assert_snapshot;
-use test_utils::covers;
+use test_utils::mark;
 
 use super::{infer, infer_with_mismatches};
 
@@ -197,7 +197,7 @@ fn test() {
 
 #[test]
 fn infer_pattern_match_ergonomics_ref() {
-    covers!(match_ergonomics_ref);
+    mark::check!(match_ergonomics_ref);
     assert_snapshot!(
         infer(r#"
 fn test() {
diff --git a/crates/ra_hir_ty/src/tests/regression.rs b/crates/ra_hir_ty/src/tests/regression.rs
index c2168222e..1f004bd63 100644
--- a/crates/ra_hir_ty/src/tests/regression.rs
+++ b/crates/ra_hir_ty/src/tests/regression.rs
@@ -1,9 +1,10 @@
 use insta::assert_snapshot;
-use test_utils::covers;
+use ra_db::fixture::WithFixture;
+use test_utils::mark;
 
-use super::infer;
 use crate::test_db::TestDB;
-use ra_db::fixture::WithFixture;
+
+use super::infer;
 
 #[test]
 fn bug_484() {
@@ -89,8 +90,8 @@ fn quux() {
 
 #[test]
 fn recursive_vars() {
-    covers!(type_var_cycles_resolve_completely);
-    covers!(type_var_cycles_resolve_as_possible);
+    mark::check!(type_var_cycles_resolve_completely);
+    mark::check!(type_var_cycles_resolve_as_possible);
     assert_snapshot!(
         infer(r#"
 fn test() {
@@ -112,8 +113,6 @@ fn test() {
 
 #[test]
 fn recursive_vars_2() {
-    covers!(type_var_cycles_resolve_completely);
-    covers!(type_var_cycles_resolve_as_possible);
     assert_snapshot!(
         infer(r#"
 fn test() {
@@ -170,7 +169,7 @@ fn write() {
 
 #[test]
 fn infer_std_crash_2() {
-    covers!(type_var_resolves_to_int_var);
+    mark::check!(type_var_resolves_to_int_var);
     // caused "equating two type variables, ...", taken from std
     assert_snapshot!(
         infer(r#"
diff --git a/crates/ra_hir_ty/src/tests/simple.rs b/crates/ra_hir_ty/src/tests/simple.rs
index 72122c070..fd2208af2 100644
--- a/crates/ra_hir_ty/src/tests/simple.rs
+++ b/crates/ra_hir_ty/src/tests/simple.rs
@@ -1860,3 +1860,66 @@ fn test() {
     "###
     );
 }
+
+#[test]
+fn infer_loop_break_with_val() {
+    assert_snapshot!(
+        infer(r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn test() {
+    let x = loop {
+        if false {
+            break None;
+        }
+
+        break Some(true);
+    };
+}
+"#),
+        @r###"
+    60..169 '{     ...  }; }': ()
+    70..71 'x': Option<bool>
+    74..166 'loop {...     }': Option<bool>
+    79..166 '{     ...     }': ()
+    89..133 'if fal...     }': ()
+    92..97 'false': bool
+    98..133 '{     ...     }': ()
+    112..122 'break None': !
+    118..122 'None': Option<bool>
+    143..159 'break ...(true)': !
+    149..153 'Some': Some<bool>(bool) -> Option<bool>
+    149..159 'Some(true)': Option<bool>
+    154..158 'true': bool
+    "###
+    );
+}
+
+#[test]
+fn infer_loop_break_without_val() {
+    assert_snapshot!(
+        infer(r#"
+enum Option<T> { Some(T), None }
+use Option::*;
+
+fn test() {
+    let x = loop {
+        if false {
+            break;
+        }
+    };
+}
+"#),
+        @r###"
+    60..137 '{     ...  }; }': ()
+    70..71 'x': ()
+    74..134 'loop {...     }': ()
+    79..134 '{     ...     }': ()
+    89..128 'if fal...     }': ()
+    92..97 'false': bool
+    98..128 '{     ...     }': ()
+    112..117 'break': !
+    "###
+    );
+}
diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs
index c49aacf98..0419bc751 100644
--- a/crates/ra_hir_ty/src/tests/traits.rs
+++ b/crates/ra_hir_ty/src/tests/traits.rs
@@ -1,10 +1,11 @@
 use insta::assert_snapshot;
-
 use ra_db::fixture::WithFixture;
+use test_utils::mark;
 
-use super::{infer, infer_with_mismatches, type_at, type_at_pos};
 use crate::test_db::TestDB;
 
+use super::{infer, infer_with_mismatches, type_at, type_at_pos};
+
 #[test]
 fn infer_await() {
     let (db, pos) = TestDB::with_position(
@@ -301,7 +302,7 @@ fn test() {
 
 #[test]
 fn trait_default_method_self_bound_implements_trait() {
-    test_utils::covers!(trait_self_implements_self);
+    mark::check!(trait_self_implements_self);
     assert_snapshot!(
         infer(r#"
 trait Trait {
@@ -324,7 +325,6 @@ trait Trait {
 
 #[test]
 fn trait_default_method_self_bound_implements_super_trait() {
-    test_utils::covers!(trait_self_implements_self);
     assert_snapshot!(
         infer(r#"
 trait SuperTrait {
@@ -2602,3 +2602,155 @@ fn test(x: &dyn Foo) {
     "###
     );
 }
+
+#[test]
+fn builtin_copy() {
+    assert_snapshot!(
+        infer_with_mismatches(r#"
+#[lang = "copy"]
+trait Copy {}
+
+struct IsCopy;
+impl Copy for IsCopy {}
+struct NotCopy;
+
+trait Test { fn test(&self) -> bool; }
+impl<T: Copy> Test for T {}
+
+fn test() {
+    IsCopy.test();
+    NotCopy.test();
+    (IsCopy, IsCopy).test();
+    (IsCopy, NotCopy).test();
+}
+"#, true),
+        @r###"
+    111..115 'self': &Self
+    167..268 '{     ...t(); }': ()
+    173..179 'IsCopy': IsCopy
+    173..186 'IsCopy.test()': bool
+    192..199 'NotCopy': NotCopy
+    192..206 'NotCopy.test()': {unknown}
+    212..228 '(IsCop...sCopy)': (IsCopy, IsCopy)
+    212..235 '(IsCop...test()': bool
+    213..219 'IsCopy': IsCopy
+    221..227 'IsCopy': IsCopy
+    241..258 '(IsCop...tCopy)': (IsCopy, NotCopy)
+    241..265 '(IsCop...test()': {unknown}
+    242..248 'IsCopy': IsCopy
+    250..257 'NotCopy': NotCopy
+    "###
+    );
+}
+
+#[test]
+fn builtin_fn_def_copy() {
+    assert_snapshot!(
+        infer_with_mismatches(r#"
+#[lang = "copy"]
+trait Copy {}
+
+fn foo() {}
+fn bar<T: Copy>(T) -> T {}
+struct Struct(usize);
+enum Enum { Variant(usize) }
+
+trait Test { fn test(&self) -> bool; }
+impl<T: Copy> Test for T {}
+
+fn test() {
+    foo.test();
+    bar.test();
+    Struct.test();
+    Enum::Variant.test();
+}
+"#, true),
+        // wrong result, because the built-in Copy impl for fn defs doesn't exist in Chalk yet
+        @r###"
+    42..44 '{}': ()
+    61..62 'T': {unknown}
+    69..71 '{}': ()
+    69..71: expected T, got ()
+    146..150 'self': &Self
+    202..282 '{     ...t(); }': ()
+    208..211 'foo': fn foo()
+    208..218 'foo.test()': {unknown}
+    224..227 'bar': fn bar<{unknown}>({unknown}) -> {unknown}
+    224..234 'bar.test()': {unknown}
+    240..246 'Struct': Struct(usize) -> Struct
+    240..253 'Struct.test()': {unknown}
+    259..272 'Enum::Variant': Variant(usize) -> Enum
+    259..279 'Enum::...test()': {unknown}
+    "###
+    );
+}
+
+#[test]
+fn builtin_fn_ptr_copy() {
+    assert_snapshot!(
+        infer_with_mismatches(r#"
+#[lang = "copy"]
+trait Copy {}
+
+trait Test { fn test(&self) -> bool; }
+impl<T: Copy> Test for T {}
+
+fn test(f1: fn(), f2: fn(usize) -> u8, f3: fn(u8, u8) -> &u8) {
+    f1.test();
+    f2.test();
+    f3.test();
+}
+"#, true),
+        @r###"
+    55..59 'self': &Self
+    109..111 'f1': fn()
+    119..121 'f2': fn(usize) -> u8
+    140..142 'f3': fn(u8, u8) -> &u8
+    163..211 '{     ...t(); }': ()
+    169..171 'f1': fn()
+    169..178 'f1.test()': bool
+    184..186 'f2': fn(usize) -> u8
+    184..193 'f2.test()': bool
+    199..201 'f3': fn(u8, u8) -> &u8
+    199..208 'f3.test()': bool
+    "###
+    );
+}
+
+#[test]
+fn builtin_sized() {
+    assert_snapshot!(
+        infer_with_mismatches(r#"
+#[lang = "sized"]
+trait Sized {}
+
+trait Test { fn test(&self) -> bool; }
+impl<T: Sized> Test for T {}
+
+fn test() {
+    1u8.test();
+    (*"foo").test(); // not Sized
+    (1u8, 1u8).test();
+    (1u8, *"foo").test(); // not Sized
+}
+"#, true),
+        @r###"
+    57..61 'self': &Self
+    114..229 '{     ...ized }': ()
+    120..123 '1u8': u8
+    120..130 '1u8.test()': bool
+    136..151 '(*"foo").test()': {unknown}
+    137..143 '*"foo"': str
+    138..143 '"foo"': &str
+    170..180 '(1u8, 1u8)': (u8, u8)
+    170..187 '(1u8, ...test()': bool
+    171..174 '1u8': u8
+    176..179 '1u8': u8
+    193..206 '(1u8, *"foo")': (u8, str)
+    193..213 '(1u8, ...test()': {unknown}
+    194..197 '1u8': u8
+    199..205 '*"foo"': str
+    200..205 '"foo"': &str
+    "###
+    );
+}
diff --git a/crates/ra_hir_ty/src/traits/chalk.rs b/crates/ra_hir_ty/src/traits/chalk.rs
index 5870618a0..5b0f12a3c 100644
--- a/crates/ra_hir_ty/src/traits/chalk.rs
+++ b/crates/ra_hir_ty/src/traits/chalk.rs
@@ -1,301 +1,29 @@
 //! Conversion code from/to Chalk.
-use std::{fmt, sync::Arc};
+use std::sync::Arc;
 
 use log::debug;
 
-use chalk_ir::{
-    cast::Cast, fold::shift::Shift, interner::HasInterner, Goal, GoalData, Parameter,
-    PlaceholderIndex, TypeName, UniverseIndex,
-};
+use chalk_ir::{fold::shift::Shift, GenericArg, TypeName};
 
-use hir_def::{AssocContainerId, AssocItemId, GenericDefId, HasModule, Lookup, TypeAliasId};
-use ra_db::{
-    salsa::{InternId, InternKey},
-    CrateId,
+use hir_def::{
+    lang_item::{lang_attr, LangItemTarget},
+    AssocContainerId, AssocItemId, HasModule, Lookup, TypeAliasId,
 };
+use ra_db::{salsa::InternKey, CrateId};
 
-use super::{builtin, AssocTyValue, Canonical, ChalkContext, Impl, Obligation};
+use super::{builtin, AssocTyValue, ChalkContext, Impl};
 use crate::{
     db::HirDatabase, display::HirDisplay, method_resolution::TyFingerprint, utils::generics,
-    ApplicationTy, DebruijnIndex, GenericPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor,
+    CallableDef, DebruijnIndex, GenericPredicate, Substs, Ty, TypeCtor,
 };
+use chalk_rust_ir::WellKnownTrait;
+use mapping::{convert_where_clauses, generic_predicate_to_inline_bound, make_binders};
 
-pub(super) mod tls;
-
-#[derive(Debug, Copy, Clone, Hash, PartialOrd, Ord, PartialEq, Eq)]
-pub struct Interner;
-
-impl chalk_ir::interner::Interner for Interner {
-    type InternedType = Box<chalk_ir::TyData<Self>>;
-    type InternedLifetime = chalk_ir::LifetimeData<Self>;
-    type InternedParameter = chalk_ir::ParameterData<Self>;
-    type InternedGoal = Arc<GoalData<Self>>;
-    type InternedGoals = Vec<Goal<Self>>;
-    type InternedSubstitution = Vec<Parameter<Self>>;
-    type InternedProgramClause = chalk_ir::ProgramClauseData<Self>;
-    type InternedProgramClauses = Arc<[chalk_ir::ProgramClause<Self>]>;
-    type InternedQuantifiedWhereClauses = Vec<chalk_ir::QuantifiedWhereClause<Self>>;
-    type InternedParameterKinds = Vec<chalk_ir::ParameterKind<()>>;
-    type InternedCanonicalVarKinds = Vec<chalk_ir::ParameterKind<UniverseIndex>>;
-    type Identifier = TypeAliasId;
-    type DefId = InternId;
-
-    fn debug_struct_id(
-        type_kind_id: StructId,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_struct_id(type_kind_id, fmt)))
-    }
-
-    fn debug_trait_id(type_kind_id: TraitId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_trait_id(type_kind_id, fmt)))
-    }
-
-    fn debug_assoc_type_id(id: AssocTypeId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_assoc_type_id(id, fmt)))
-    }
-
-    fn debug_alias(
-        alias: &chalk_ir::AliasTy<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_alias(alias, fmt)))
-    }
-
-    fn debug_projection_ty(
-        proj: &chalk_ir::ProjectionTy<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_projection_ty(proj, fmt)))
-    }
-
-    fn debug_opaque_ty(
-        opaque_ty: &chalk_ir::OpaqueTy<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_opaque_ty(opaque_ty, fmt)))
-    }
-
-    fn debug_opaque_ty_id(
-        opaque_ty_id: chalk_ir::OpaqueTyId<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_opaque_ty_id(opaque_ty_id, fmt)))
-    }
-
-    fn debug_ty(ty: &chalk_ir::Ty<Interner>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_ty(ty, fmt)))
-    }
-
-    fn debug_lifetime(
-        lifetime: &chalk_ir::Lifetime<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_lifetime(lifetime, fmt)))
-    }
-
-    fn debug_parameter(
-        parameter: &Parameter<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_parameter(parameter, fmt)))
-    }
-
-    fn debug_goal(goal: &Goal<Interner>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_goal(goal, fmt)))
-    }
-
-    fn debug_goals(
-        goals: &chalk_ir::Goals<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_goals(goals, fmt)))
-    }
-
-    fn debug_program_clause_implication(
-        pci: &chalk_ir::ProgramClauseImplication<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_program_clause_implication(pci, fmt)))
-    }
-
-    fn debug_application_ty(
-        application_ty: &chalk_ir::ApplicationTy<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_application_ty(application_ty, fmt)))
-    }
-
-    fn debug_substitution(
-        substitution: &chalk_ir::Substitution<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| Some(prog?.debug_substitution(substitution, fmt)))
-    }
-
-    fn debug_separator_trait_ref(
-        separator_trait_ref: &chalk_ir::SeparatorTraitRef<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
-        tls::with_current_program(|prog| {
-            Some(prog?.debug_separator_trait_ref(separator_trait_ref, fmt))
-        })
-    }
-
-    fn intern_ty(&self, ty: chalk_ir::TyData<Self>) -> Box<chalk_ir::TyData<Self>> {
-        Box::new(ty)
-    }
-
-    fn ty_data<'a>(&self, ty: &'a Box<chalk_ir::TyData<Self>>) -> &'a chalk_ir::TyData<Self> {
-        ty
-    }
-
-    fn intern_lifetime(
-        &self,
-        lifetime: chalk_ir::LifetimeData<Self>,
-    ) -> chalk_ir::LifetimeData<Self> {
-        lifetime
-    }
-
-    fn lifetime_data<'a>(
-        &self,
-        lifetime: &'a chalk_ir::LifetimeData<Self>,
-    ) -> &'a chalk_ir::LifetimeData<Self> {
-        lifetime
-    }
-
-    fn intern_parameter(
-        &self,
-        parameter: chalk_ir::ParameterData<Self>,
-    ) -> chalk_ir::ParameterData<Self> {
-        parameter
-    }
-
-    fn parameter_data<'a>(
-        &self,
-        parameter: &'a chalk_ir::ParameterData<Self>,
-    ) -> &'a chalk_ir::ParameterData<Self> {
-        parameter
-    }
-
-    fn intern_goal(&self, goal: GoalData<Self>) -> Arc<GoalData<Self>> {
-        Arc::new(goal)
-    }
-
-    fn intern_goals<E>(
-        &self,
-        data: impl IntoIterator<Item = Result<Goal<Self>, E>>,
-    ) -> Result<Self::InternedGoals, E> {
-        data.into_iter().collect()
-    }
-
-    fn goal_data<'a>(&self, goal: &'a Arc<GoalData<Self>>) -> &'a GoalData<Self> {
-        goal
-    }
-
-    fn goals_data<'a>(&self, goals: &'a Vec<Goal<Interner>>) -> &'a [Goal<Interner>] {
-        goals
-    }
-
-    fn intern_substitution<E>(
-        &self,
-        data: impl IntoIterator<Item = Result<Parameter<Self>, E>>,
-    ) -> Result<Vec<Parameter<Self>>, E> {
-        data.into_iter().collect()
-    }
-
-    fn substitution_data<'a>(
-        &self,
-        substitution: &'a Vec<Parameter<Self>>,
-    ) -> &'a [Parameter<Self>] {
-        substitution
-    }
-
-    fn intern_program_clause(
-        &self,
-        data: chalk_ir::ProgramClauseData<Self>,
-    ) -> chalk_ir::ProgramClauseData<Self> {
-        data
-    }
-
-    fn program_clause_data<'a>(
-        &self,
-        clause: &'a chalk_ir::ProgramClauseData<Self>,
-    ) -> &'a chalk_ir::ProgramClauseData<Self> {
-        clause
-    }
-
-    fn intern_program_clauses<E>(
-        &self,
-        data: impl IntoIterator<Item = Result<chalk_ir::ProgramClause<Self>, E>>,
-    ) -> Result<Arc<[chalk_ir::ProgramClause<Self>]>, E> {
-        data.into_iter().collect()
-    }
-
-    fn program_clauses_data<'a>(
-        &self,
-        clauses: &'a Arc<[chalk_ir::ProgramClause<Self>]>,
-    ) -> &'a [chalk_ir::ProgramClause<Self>] {
-        &clauses
-    }
-
-    fn intern_quantified_where_clauses<E>(
-        &self,
-        data: impl IntoIterator<Item = Result<chalk_ir::QuantifiedWhereClause<Self>, E>>,
-    ) -> Result<Self::InternedQuantifiedWhereClauses, E> {
-        data.into_iter().collect()
-    }
-
-    fn quantified_where_clauses_data<'a>(
-        &self,
-        clauses: &'a Self::InternedQuantifiedWhereClauses,
-    ) -> &'a [chalk_ir::QuantifiedWhereClause<Self>] {
-        clauses
-    }
-
-    fn intern_parameter_kinds<E>(
-        &self,
-        data: impl IntoIterator<Item = Result<chalk_ir::ParameterKind<()>, E>>,
-    ) -> Result<Self::InternedParameterKinds, E> {
-        data.into_iter().collect()
-    }
+pub use self::interner::*;
 
-    fn parameter_kinds_data<'a>(
-        &self,
-        parameter_kinds: &'a Self::InternedParameterKinds,
-    ) -> &'a [chalk_ir::ParameterKind<()>] {
-        &parameter_kinds
-    }
-
-    fn intern_canonical_var_kinds<E>(
-        &self,
-        data: impl IntoIterator<Item = Result<chalk_ir::ParameterKind<UniverseIndex>, E>>,
-    ) -> Result<Self::InternedCanonicalVarKinds, E> {
-        data.into_iter().collect()
-    }
-
-    fn canonical_var_kinds_data<'a>(
-        &self,
-        canonical_var_kinds: &'a Self::InternedCanonicalVarKinds,
-    ) -> &'a [chalk_ir::ParameterKind<UniverseIndex>] {
-        &canonical_var_kinds
-    }
-}
-
-impl chalk_ir::interner::HasInterner for Interner {
-    type Interner = Self;
-}
-
-pub type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
-pub type AssociatedTyDatum = chalk_rust_ir::AssociatedTyDatum<Interner>;
-pub type TraitId = chalk_ir::TraitId<Interner>;
-pub type TraitDatum = chalk_rust_ir::TraitDatum<Interner>;
-pub type StructId = chalk_ir::StructId<Interner>;
-pub type StructDatum = chalk_rust_ir::StructDatum<Interner>;
-pub type ImplId = chalk_ir::ImplId<Interner>;
-pub type ImplDatum = chalk_rust_ir::ImplDatum<Interner>;
-pub type AssociatedTyValueId = chalk_rust_ir::AssociatedTyValueId<Interner>;
-pub type AssociatedTyValue = chalk_rust_ir::AssociatedTyValue<Interner>;
+pub(super) mod tls;
+mod interner;
+mod mapping;
 
 pub(super) trait ToChalk {
     type Chalk;
@@ -310,508 +38,6 @@ where
     T::from_chalk(db, chalk)
 }
 
-impl ToChalk for Ty {
-    type Chalk = chalk_ir::Ty<Interner>;
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Ty<Interner> {
-        match self {
-            Ty::Apply(apply_ty) => {
-                let name = apply_ty.ctor.to_chalk(db);
-                let substitution = apply_ty.parameters.to_chalk(db);
-                chalk_ir::ApplicationTy { name, substitution }.cast(&Interner).intern(&Interner)
-            }
-            Ty::Projection(proj_ty) => {
-                let associated_ty_id = proj_ty.associated_ty.to_chalk(db);
-                let substitution = proj_ty.parameters.to_chalk(db);
-                chalk_ir::AliasTy::Projection(chalk_ir::ProjectionTy {
-                    associated_ty_id,
-                    substitution,
-                })
-                .cast(&Interner)
-                .intern(&Interner)
-            }
-            Ty::Placeholder(id) => {
-                let interned_id = db.intern_type_param_id(id);
-                PlaceholderIndex {
-                    ui: UniverseIndex::ROOT,
-                    idx: interned_id.as_intern_id().as_usize(),
-                }
-                .to_ty::<Interner>(&Interner)
-            }
-            Ty::Bound(idx) => chalk_ir::TyData::BoundVar(idx).intern(&Interner),
-            Ty::Infer(_infer_ty) => panic!("uncanonicalized infer ty"),
-            Ty::Dyn(predicates) => {
-                let where_clauses = chalk_ir::QuantifiedWhereClauses::from(
-                    &Interner,
-                    predicates.iter().filter(|p| !p.is_error()).cloned().map(|p| p.to_chalk(db)),
-                );
-                let bounded_ty = chalk_ir::DynTy { bounds: make_binders(where_clauses, 1) };
-                chalk_ir::TyData::Dyn(bounded_ty).intern(&Interner)
-            }
-            Ty::Opaque(_) | Ty::Unknown => {
-                let substitution = chalk_ir::Substitution::empty(&Interner);
-                let name = TypeName::Error;
-                chalk_ir::ApplicationTy { name, substitution }.cast(&Interner).intern(&Interner)
-            }
-        }
-    }
-    fn from_chalk(db: &dyn HirDatabase, chalk: chalk_ir::Ty<Interner>) -> Self {
-        match chalk.data(&Interner).clone() {
-            chalk_ir::TyData::Apply(apply_ty) => match apply_ty.name {
-                TypeName::Error => Ty::Unknown,
-                _ => {
-                    let ctor = from_chalk(db, apply_ty.name);
-                    let parameters = from_chalk(db, apply_ty.substitution);
-                    Ty::Apply(ApplicationTy { ctor, parameters })
-                }
-            },
-            chalk_ir::TyData::Placeholder(idx) => {
-                assert_eq!(idx.ui, UniverseIndex::ROOT);
-                let interned_id = crate::db::GlobalTypeParamId::from_intern_id(
-                    crate::salsa::InternId::from(idx.idx),
-                );
-                Ty::Placeholder(db.lookup_intern_type_param_id(interned_id))
-            }
-            chalk_ir::TyData::Alias(chalk_ir::AliasTy::Projection(proj)) => {
-                let associated_ty = from_chalk(db, proj.associated_ty_id);
-                let parameters = from_chalk(db, proj.substitution);
-                Ty::Projection(ProjectionTy { associated_ty, parameters })
-            }
-            chalk_ir::TyData::Alias(chalk_ir::AliasTy::Opaque(_)) => unimplemented!(),
-            chalk_ir::TyData::Function(_) => unimplemented!(),
-            chalk_ir::TyData::BoundVar(idx) => Ty::Bound(idx),
-            chalk_ir::TyData::InferenceVar(_iv) => Ty::Unknown,
-            chalk_ir::TyData::Dyn(where_clauses) => {
-                assert_eq!(where_clauses.bounds.binders.len(&Interner), 1);
-                let predicates = where_clauses
-                    .bounds
-                    .skip_binders()
-                    .iter(&Interner)
-                    .map(|c| from_chalk(db, c.clone()))
-                    .collect();
-                Ty::Dyn(predicates)
-            }
-        }
-    }
-}
-
-impl ToChalk for Substs {
-    type Chalk = chalk_ir::Substitution<Interner>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Substitution<Interner> {
-        chalk_ir::Substitution::from(&Interner, self.iter().map(|ty| ty.clone().to_chalk(db)))
-    }
-
-    fn from_chalk(db: &dyn HirDatabase, parameters: chalk_ir::Substitution<Interner>) -> Substs {
-        let tys = parameters
-            .iter(&Interner)
-            .map(|p| match p.ty(&Interner) {
-                Some(ty) => from_chalk(db, ty.clone()),
-                None => unimplemented!(),
-            })
-            .collect();
-        Substs(tys)
-    }
-}
-
-impl ToChalk for TraitRef {
-    type Chalk = chalk_ir::TraitRef<Interner>;
-
-    fn to_chalk(self: TraitRef, db: &dyn HirDatabase) -> chalk_ir::TraitRef<Interner> {
-        let trait_id = self.trait_.to_chalk(db);
-        let substitution = self.substs.to_chalk(db);
-        chalk_ir::TraitRef { trait_id, substitution }
-    }
-
-    fn from_chalk(db: &dyn HirDatabase, trait_ref: chalk_ir::TraitRef<Interner>) -> Self {
-        let trait_ = from_chalk(db, trait_ref.trait_id);
-        let substs = from_chalk(db, trait_ref.substitution);
-        TraitRef { trait_, substs }
-    }
-}
-
-impl ToChalk for hir_def::TraitId {
-    type Chalk = TraitId;
-
-    fn to_chalk(self, _db: &dyn HirDatabase) -> TraitId {
-        chalk_ir::TraitId(self.as_intern_id())
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, trait_id: TraitId) -> hir_def::TraitId {
-        InternKey::from_intern_id(trait_id.0)
-    }
-}
-
-impl ToChalk for TypeCtor {
-    type Chalk = TypeName<Interner>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> TypeName<Interner> {
-        match self {
-            TypeCtor::AssociatedType(type_alias) => {
-                let type_id = type_alias.to_chalk(db);
-                TypeName::AssociatedType(type_id)
-            }
-            _ => {
-                // other TypeCtors get interned and turned into a chalk StructId
-                let struct_id = db.intern_type_ctor(self).into();
-                TypeName::Struct(struct_id)
-            }
-        }
-    }
-
-    fn from_chalk(db: &dyn HirDatabase, type_name: TypeName<Interner>) -> TypeCtor {
-        match type_name {
-            TypeName::Struct(struct_id) => db.lookup_intern_type_ctor(struct_id.into()),
-            TypeName::AssociatedType(type_id) => TypeCtor::AssociatedType(from_chalk(db, type_id)),
-            TypeName::OpaqueType(_) => unreachable!(),
-
-            TypeName::Scalar(_) => unreachable!(),
-            TypeName::Tuple(_) => unreachable!(),
-            TypeName::Raw(_) => unreachable!(),
-            TypeName::Slice => unreachable!(),
-            TypeName::Ref(_) => unreachable!(),
-            TypeName::Str => unreachable!(),
-
-            TypeName::Error => {
-                // this should not be reached, since we don't represent TypeName::Error with TypeCtor
-                unreachable!()
-            }
-        }
-    }
-}
-
-impl ToChalk for Impl {
-    type Chalk = ImplId;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> ImplId {
-        db.intern_chalk_impl(self).into()
-    }
-
-    fn from_chalk(db: &dyn HirDatabase, impl_id: ImplId) -> Impl {
-        db.lookup_intern_chalk_impl(impl_id.into())
-    }
-}
-
-impl ToChalk for TypeAliasId {
-    type Chalk = AssocTypeId;
-
-    fn to_chalk(self, _db: &dyn HirDatabase) -> AssocTypeId {
-        chalk_ir::AssocTypeId(self.as_intern_id())
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, type_alias_id: AssocTypeId) -> TypeAliasId {
-        InternKey::from_intern_id(type_alias_id.0)
-    }
-}
-
-impl ToChalk for AssocTyValue {
-    type Chalk = AssociatedTyValueId;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> AssociatedTyValueId {
-        db.intern_assoc_ty_value(self).into()
-    }
-
-    fn from_chalk(db: &dyn HirDatabase, assoc_ty_value_id: AssociatedTyValueId) -> AssocTyValue {
-        db.lookup_intern_assoc_ty_value(assoc_ty_value_id.into())
-    }
-}
-
-impl ToChalk for GenericPredicate {
-    type Chalk = chalk_ir::QuantifiedWhereClause<Interner>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::QuantifiedWhereClause<Interner> {
-        match self {
-            GenericPredicate::Implemented(trait_ref) => {
-                let chalk_trait_ref = trait_ref.to_chalk(db);
-                let chalk_trait_ref = chalk_trait_ref.shifted_in(&Interner);
-                make_binders(chalk_ir::WhereClause::Implemented(chalk_trait_ref), 0)
-            }
-            GenericPredicate::Projection(projection_pred) => {
-                let ty = projection_pred.ty.to_chalk(db).shifted_in(&Interner);
-                let projection = projection_pred.projection_ty.to_chalk(db).shifted_in(&Interner);
-                let alias = chalk_ir::AliasTy::Projection(projection);
-                make_binders(chalk_ir::WhereClause::AliasEq(chalk_ir::AliasEq { alias, ty }), 0)
-            }
-            GenericPredicate::Error => panic!("tried passing GenericPredicate::Error to Chalk"),
-        }
-    }
-
-    fn from_chalk(
-        db: &dyn HirDatabase,
-        where_clause: chalk_ir::QuantifiedWhereClause<Interner>,
-    ) -> GenericPredicate {
-        // we don't produce any where clauses with binders and can't currently deal with them
-        match where_clause
-            .skip_binders()
-            .shifted_out(&Interner)
-            .expect("unexpected bound vars in where clause")
-        {
-            chalk_ir::WhereClause::Implemented(tr) => {
-                GenericPredicate::Implemented(from_chalk(db, tr))
-            }
-            chalk_ir::WhereClause::AliasEq(projection_eq) => {
-                let projection_ty = from_chalk(
-                    db,
-                    match projection_eq.alias {
-                        chalk_ir::AliasTy::Projection(p) => p,
-                        _ => unimplemented!(),
-                    },
-                );
-                let ty = from_chalk(db, projection_eq.ty);
-                GenericPredicate::Projection(super::ProjectionPredicate { projection_ty, ty })
-            }
-        }
-    }
-}
-
-impl ToChalk for ProjectionTy {
-    type Chalk = chalk_ir::ProjectionTy<Interner>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::ProjectionTy<Interner> {
-        chalk_ir::ProjectionTy {
-            associated_ty_id: self.associated_ty.to_chalk(db),
-            substitution: self.parameters.to_chalk(db),
-        }
-    }
-
-    fn from_chalk(
-        db: &dyn HirDatabase,
-        projection_ty: chalk_ir::ProjectionTy<Interner>,
-    ) -> ProjectionTy {
-        ProjectionTy {
-            associated_ty: from_chalk(db, projection_ty.associated_ty_id),
-            parameters: from_chalk(db, projection_ty.substitution),
-        }
-    }
-}
-
-impl ToChalk for super::ProjectionPredicate {
-    type Chalk = chalk_ir::AliasEq<Interner>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::AliasEq<Interner> {
-        chalk_ir::AliasEq {
-            alias: chalk_ir::AliasTy::Projection(self.projection_ty.to_chalk(db)),
-            ty: self.ty.to_chalk(db),
-        }
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, _normalize: chalk_ir::AliasEq<Interner>) -> Self {
-        unimplemented!()
-    }
-}
-
-impl ToChalk for Obligation {
-    type Chalk = chalk_ir::DomainGoal<Interner>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::DomainGoal<Interner> {
-        match self {
-            Obligation::Trait(tr) => tr.to_chalk(db).cast(&Interner),
-            Obligation::Projection(pr) => pr.to_chalk(db).cast(&Interner),
-        }
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, _goal: chalk_ir::DomainGoal<Interner>) -> Self {
-        unimplemented!()
-    }
-}
-
-impl<T> ToChalk for Canonical<T>
-where
-    T: ToChalk,
-    T::Chalk: HasInterner<Interner = Interner>,
-{
-    type Chalk = chalk_ir::Canonical<T::Chalk>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Canonical<T::Chalk> {
-        let parameter = chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::ROOT);
-        let value = self.value.to_chalk(db);
-        chalk_ir::Canonical {
-            value,
-            binders: chalk_ir::CanonicalVarKinds::from(&Interner, vec![parameter; self.num_vars]),
-        }
-    }
-
-    fn from_chalk(db: &dyn HirDatabase, canonical: chalk_ir::Canonical<T::Chalk>) -> Canonical<T> {
-        Canonical {
-            num_vars: canonical.binders.len(&Interner),
-            value: from_chalk(db, canonical.value),
-        }
-    }
-}
-
-impl ToChalk for Arc<super::TraitEnvironment> {
-    type Chalk = chalk_ir::Environment<Interner>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Environment<Interner> {
-        let mut clauses = Vec::new();
-        for pred in &self.predicates {
-            if pred.is_error() {
-                // for env, we just ignore errors
-                continue;
-            }
-            let program_clause: chalk_ir::ProgramClause<Interner> =
-                pred.clone().to_chalk(db).cast(&Interner);
-            clauses.push(program_clause.into_from_env_clause(&Interner));
-        }
-        chalk_ir::Environment::new(&Interner).add_clauses(&Interner, clauses)
-    }
-
-    fn from_chalk(
-        _db: &dyn HirDatabase,
-        _env: chalk_ir::Environment<Interner>,
-    ) -> Arc<super::TraitEnvironment> {
-        unimplemented!()
-    }
-}
-
-impl<T: ToChalk> ToChalk for super::InEnvironment<T>
-where
-    T::Chalk: chalk_ir::interner::HasInterner<Interner = Interner>,
-{
-    type Chalk = chalk_ir::InEnvironment<T::Chalk>;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::InEnvironment<T::Chalk> {
-        chalk_ir::InEnvironment {
-            environment: self.environment.to_chalk(db),
-            goal: self.value.to_chalk(db),
-        }
-    }
-
-    fn from_chalk(
-        db: &dyn HirDatabase,
-        in_env: chalk_ir::InEnvironment<T::Chalk>,
-    ) -> super::InEnvironment<T> {
-        super::InEnvironment {
-            environment: from_chalk(db, in_env.environment),
-            value: from_chalk(db, in_env.goal),
-        }
-    }
-}
-
-impl ToChalk for builtin::BuiltinImplData {
-    type Chalk = ImplDatum;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> ImplDatum {
-        let impl_type = chalk_rust_ir::ImplType::External;
-        let where_clauses = self.where_clauses.into_iter().map(|w| w.to_chalk(db)).collect();
-
-        let impl_datum_bound =
-            chalk_rust_ir::ImplDatumBound { trait_ref: self.trait_ref.to_chalk(db), where_clauses };
-        let associated_ty_value_ids =
-            self.assoc_ty_values.into_iter().map(|v| v.to_chalk(db)).collect();
-        chalk_rust_ir::ImplDatum {
-            binders: make_binders(impl_datum_bound, self.num_vars),
-            impl_type,
-            polarity: chalk_rust_ir::Polarity::Positive,
-            associated_ty_value_ids,
-        }
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, _data: ImplDatum) -> Self {
-        unimplemented!()
-    }
-}
-
-impl ToChalk for builtin::BuiltinImplAssocTyValueData {
-    type Chalk = AssociatedTyValue;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> AssociatedTyValue {
-        let ty = self.value.to_chalk(db);
-        let value_bound = chalk_rust_ir::AssociatedTyValueBound { ty };
-
-        chalk_rust_ir::AssociatedTyValue {
-            associated_ty_id: self.assoc_ty_id.to_chalk(db),
-            impl_id: self.impl_.to_chalk(db),
-            value: make_binders(value_bound, self.num_vars),
-        }
-    }
-
-    fn from_chalk(
-        _db: &dyn HirDatabase,
-        _data: AssociatedTyValue,
-    ) -> builtin::BuiltinImplAssocTyValueData {
-        unimplemented!()
-    }
-}
-
-fn make_binders<T>(value: T, num_vars: usize) -> chalk_ir::Binders<T>
-where
-    T: HasInterner<Interner = Interner>,
-{
-    chalk_ir::Binders::new(
-        chalk_ir::ParameterKinds::from(
-            &Interner,
-            std::iter::repeat(chalk_ir::ParameterKind::Ty(())).take(num_vars),
-        ),
-        value,
-    )
-}
-
-fn convert_where_clauses(
-    db: &dyn HirDatabase,
-    def: GenericDefId,
-    substs: &Substs,
-) -> Vec<chalk_ir::QuantifiedWhereClause<Interner>> {
-    let generic_predicates = db.generic_predicates(def);
-    let mut result = Vec::with_capacity(generic_predicates.len());
-    for pred in generic_predicates.iter() {
-        if pred.value.is_error() {
-            // skip errored predicates completely
-            continue;
-        }
-        result.push(pred.clone().subst(substs).to_chalk(db));
-    }
-    result
-}
-
-fn generic_predicate_to_inline_bound(
-    db: &dyn HirDatabase,
-    pred: &GenericPredicate,
-    self_ty: &Ty,
-) -> Option<chalk_rust_ir::InlineBound<Interner>> {
-    // An InlineBound is like a GenericPredicate, except the self type is left out.
-    // We don't have a special type for this, but Chalk does.
-    match pred {
-        GenericPredicate::Implemented(trait_ref) => {
-            if &trait_ref.substs[0] != self_ty {
-                // we can only convert predicates back to type bounds if they
-                // have the expected self type
-                return None;
-            }
-            let args_no_self = trait_ref.substs[1..]
-                .iter()
-                .map(|ty| ty.clone().to_chalk(db).cast(&Interner))
-                .collect();
-            let trait_bound =
-                chalk_rust_ir::TraitBound { trait_id: trait_ref.trait_.to_chalk(db), args_no_self };
-            Some(chalk_rust_ir::InlineBound::TraitBound(trait_bound))
-        }
-        GenericPredicate::Projection(proj) => {
-            if &proj.projection_ty.parameters[0] != self_ty {
-                return None;
-            }
-            let trait_ = match proj.projection_ty.associated_ty.lookup(db.upcast()).container {
-                AssocContainerId::TraitId(t) => t,
-                _ => panic!("associated type not in trait"),
-            };
-            let args_no_self = proj.projection_ty.parameters[1..]
-                .iter()
-                .map(|ty| ty.clone().to_chalk(db).cast(&Interner))
-                .collect();
-            let alias_eq_bound = chalk_rust_ir::AliasEqBound {
-                value: proj.ty.clone().to_chalk(db),
-                trait_bound: chalk_rust_ir::TraitBound {
-                    trait_id: trait_.to_chalk(db),
-                    args_no_self,
-                },
-                associated_ty_id: proj.projection_ty.associated_ty.to_chalk(db),
-                parameters: Vec::new(), // FIXME we don't support generic associated types yet
-            };
-            Some(chalk_rust_ir::InlineBound::AliasEqBound(alias_eq_bound))
-        }
-        GenericPredicate::Error => None,
-    }
-}
-
 impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     fn associated_ty_data(&self, id: AssocTypeId) -> Arc<AssociatedTyDatum> {
         self.db.associated_ty_data(id)
@@ -819,16 +45,24 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     fn trait_datum(&self, trait_id: TraitId) -> Arc<TraitDatum> {
         self.db.trait_datum(self.krate, trait_id)
     }
-    fn struct_datum(&self, struct_id: StructId) -> Arc<StructDatum> {
+    fn adt_datum(&self, struct_id: AdtId) -> Arc<StructDatum> {
         self.db.struct_datum(self.krate, struct_id)
     }
     fn impl_datum(&self, impl_id: ImplId) -> Arc<ImplDatum> {
         self.db.impl_datum(self.krate, impl_id)
     }
+
+    fn fn_def_datum(
+        &self,
+        fn_def_id: chalk_ir::FnDefId<Interner>,
+    ) -> Arc<chalk_rust_ir::FnDefDatum<Interner>> {
+        self.db.fn_def_datum(self.krate, fn_def_id)
+    }
+
     fn impls_for_trait(
         &self,
         trait_id: TraitId,
-        parameters: &[Parameter<Interner>],
+        parameters: &[GenericArg<Interner>],
     ) -> Vec<ImplId> {
         debug!("impls_for_trait {:?}", trait_id);
         let trait_: hir_def::TraitId = from_chalk(self.db, trait_id);
@@ -859,7 +93,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         debug!("impls_for_trait returned {} impls", result.len());
         result
     }
-    fn impl_provided_for(&self, auto_trait_id: TraitId, struct_id: StructId) -> bool {
+    fn impl_provided_for(&self, auto_trait_id: TraitId, struct_id: AdtId) -> bool {
         debug!("impl_provided_for {:?}, {:?}", auto_trait_id, struct_id);
         false // FIXME
     }
@@ -878,10 +112,15 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     }
     fn well_known_trait_id(
         &self,
-        _well_known_trait: chalk_rust_ir::WellKnownTrait,
+        well_known_trait: chalk_rust_ir::WellKnownTrait,
     ) -> Option<chalk_ir::TraitId<Interner>> {
-        // FIXME tell Chalk about well-known traits (here and in trait_datum)
-        None
+        let lang_attr = lang_attr_from_well_known_trait(well_known_trait);
+        let lang_items = self.db.crate_lang_items(self.krate);
+        let trait_ = match lang_items.target(lang_attr) {
+            Some(LangItemTarget::TraitId(trait_)) => trait_,
+            _ => return None,
+        };
+        Some(trait_.to_chalk(self.db))
     }
 
     fn program_clauses_for_env(
@@ -983,7 +222,8 @@ pub(crate) fn trait_datum_query(
     let associated_ty_ids =
         trait_data.associated_types().map(|type_alias| type_alias.to_chalk(db)).collect();
     let trait_datum_bound = chalk_rust_ir::TraitDatumBound { where_clauses };
-    let well_known = None; // FIXME set this (depending on lang items)
+    let well_known =
+        lang_attr(db.upcast(), trait_).and_then(|name| well_known_trait_from_lang_attr(&name));
     let trait_datum = TraitDatum {
         id: trait_id,
         binders: make_binders(trait_datum_bound, bound_vars.len()),
@@ -994,13 +234,32 @@ pub(crate) fn trait_datum_query(
     Arc::new(trait_datum)
 }
 
+fn well_known_trait_from_lang_attr(name: &str) -> Option<WellKnownTrait> {
+    Some(match name {
+        "sized" => WellKnownTrait::SizedTrait,
+        "copy" => WellKnownTrait::CopyTrait,
+        "clone" => WellKnownTrait::CloneTrait,
+        "drop" => WellKnownTrait::DropTrait,
+        _ => return None,
+    })
+}
+
+fn lang_attr_from_well_known_trait(attr: WellKnownTrait) -> &'static str {
+    match attr {
+        WellKnownTrait::SizedTrait => "sized",
+        WellKnownTrait::CopyTrait => "copy",
+        WellKnownTrait::CloneTrait => "clone",
+        WellKnownTrait::DropTrait => "drop",
+    }
+}
+
 pub(crate) fn struct_datum_query(
     db: &dyn HirDatabase,
     krate: CrateId,
-    struct_id: StructId,
+    struct_id: AdtId,
 ) -> Arc<StructDatum> {
     debug!("struct_datum {:?}", struct_id);
-    let type_ctor: TypeCtor = from_chalk(db, TypeName::Struct(struct_id));
+    let type_ctor: TypeCtor = from_chalk(db, TypeName::Adt(struct_id));
     debug!("struct {:?} = {:?}", struct_id, type_ctor);
     let num_params = type_ctor.num_ty_params(db);
     let upstream = type_ctor.krate(db) != Some(krate);
@@ -1012,12 +271,12 @@ pub(crate) fn struct_datum_query(
             convert_where_clauses(db, generic_def, &bound_vars)
         })
         .unwrap_or_else(Vec::new);
-    let flags = chalk_rust_ir::StructFlags {
+    let flags = chalk_rust_ir::AdtFlags {
         upstream,
         // FIXME set fundamental flag correctly
         fundamental: false,
     };
-    let struct_datum_bound = chalk_rust_ir::StructDatumBound {
+    let struct_datum_bound = chalk_rust_ir::AdtDatumBound {
         fields: Vec::new(), // FIXME add fields (only relevant for auto traits)
         where_clauses,
     };
@@ -1145,15 +404,47 @@ fn type_alias_associated_ty_value(
     Arc::new(value)
 }
 
-impl From<StructId> for crate::TypeCtorId {
-    fn from(struct_id: StructId) -> Self {
-        InternKey::from_intern_id(struct_id.0)
+pub(crate) fn fn_def_datum_query(
+    db: &dyn HirDatabase,
+    _krate: CrateId,
+    fn_def_id: FnDefId,
+) -> Arc<FnDefDatum> {
+    let callable_def: CallableDef = from_chalk(db, fn_def_id);
+    let generic_params = generics(db.upcast(), callable_def.into());
+    let sig = db.callable_item_signature(callable_def);
+    let bound_vars = Substs::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let where_clauses = convert_where_clauses(db, callable_def.into(), &bound_vars);
+    let bound = chalk_rust_ir::FnDefDatumBound {
+        // Note: Chalk doesn't actually use this information yet as far as I am aware, but we provide it anyway
+        argument_types: sig.value.params().iter().map(|ty| ty.clone().to_chalk(db)).collect(),
+        return_type: sig.value.ret().clone().to_chalk(db),
+        where_clauses,
+    };
+    let datum = FnDefDatum { id: fn_def_id, binders: make_binders(bound, sig.num_binders) };
+    Arc::new(datum)
+}
+
+impl From<AdtId> for crate::TypeCtorId {
+    fn from(struct_id: AdtId) -> Self {
+        struct_id.0
     }
 }
 
-impl From<crate::TypeCtorId> for StructId {
+impl From<crate::TypeCtorId> for AdtId {
     fn from(type_ctor_id: crate::TypeCtorId) -> Self {
-        chalk_ir::StructId(type_ctor_id.as_intern_id())
+        chalk_ir::AdtId(type_ctor_id)
+    }
+}
+
+impl From<FnDefId> for crate::CallableDefId {
+    fn from(fn_def_id: FnDefId) -> Self {
+        InternKey::from_intern_id(fn_def_id.0)
+    }
+}
+
+impl From<crate::CallableDefId> for FnDefId {
+    fn from(callable_def_id: crate::CallableDefId) -> Self {
+        chalk_ir::FnDefId(callable_def_id.as_intern_id())
     }
 }
 
diff --git a/crates/ra_hir_ty/src/traits/chalk/interner.rs b/crates/ra_hir_ty/src/traits/chalk/interner.rs
new file mode 100644
index 000000000..2a27f8ed8
--- /dev/null
+++ b/crates/ra_hir_ty/src/traits/chalk/interner.rs
@@ -0,0 +1,353 @@
+//! Implementation of the Chalk `Interner` trait, which allows customizing the
+//! representation of the various objects Chalk deals with (types, goals etc.).
+
+use super::tls;
+use chalk_ir::{GenericArg, Goal, GoalData};
+use hir_def::TypeAliasId;
+use ra_db::salsa::InternId;
+use std::{fmt, sync::Arc};
+
+#[derive(Debug, Copy, Clone, Hash, PartialOrd, Ord, PartialEq, Eq)]
+pub struct Interner;
+
+pub type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
+pub type AssociatedTyDatum = chalk_rust_ir::AssociatedTyDatum<Interner>;
+pub type TraitId = chalk_ir::TraitId<Interner>;
+pub type TraitDatum = chalk_rust_ir::TraitDatum<Interner>;
+pub type AdtId = chalk_ir::AdtId<Interner>;
+pub type StructDatum = chalk_rust_ir::AdtDatum<Interner>;
+pub type ImplId = chalk_ir::ImplId<Interner>;
+pub type ImplDatum = chalk_rust_ir::ImplDatum<Interner>;
+pub type AssociatedTyValueId = chalk_rust_ir::AssociatedTyValueId<Interner>;
+pub type AssociatedTyValue = chalk_rust_ir::AssociatedTyValue<Interner>;
+pub type FnDefId = chalk_ir::FnDefId<Interner>;
+pub type FnDefDatum = chalk_rust_ir::FnDefDatum<Interner>;
+
+impl chalk_ir::interner::Interner for Interner {
+    type InternedType = Box<chalk_ir::TyData<Self>>; // FIXME use Arc?
+    type InternedLifetime = chalk_ir::LifetimeData<Self>;
+    type InternedConst = Arc<chalk_ir::ConstData<Self>>;
+    type InternedConcreteConst = ();
+    type InternedGenericArg = chalk_ir::GenericArgData<Self>;
+    type InternedGoal = Arc<GoalData<Self>>;
+    type InternedGoals = Vec<Goal<Self>>;
+    type InternedSubstitution = Vec<GenericArg<Self>>;
+    type InternedProgramClause = chalk_ir::ProgramClauseData<Self>;
+    type InternedProgramClauses = Arc<[chalk_ir::ProgramClause<Self>]>;
+    type InternedQuantifiedWhereClauses = Vec<chalk_ir::QuantifiedWhereClause<Self>>;
+    type InternedVariableKinds = Vec<chalk_ir::VariableKind<Self>>;
+    type InternedCanonicalVarKinds = Vec<chalk_ir::CanonicalVarKind<Self>>;
+    type DefId = InternId;
+    type InternedAdtId = crate::TypeCtorId;
+    type Identifier = TypeAliasId;
+
+    fn debug_adt_id(type_kind_id: AdtId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_struct_id(type_kind_id, fmt)))
+    }
+
+    fn debug_trait_id(type_kind_id: TraitId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_trait_id(type_kind_id, fmt)))
+    }
+
+    fn debug_assoc_type_id(id: AssocTypeId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_assoc_type_id(id, fmt)))
+    }
+
+    fn debug_alias(
+        alias: &chalk_ir::AliasTy<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_alias(alias, fmt)))
+    }
+
+    fn debug_projection_ty(
+        proj: &chalk_ir::ProjectionTy<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_projection_ty(proj, fmt)))
+    }
+
+    fn debug_opaque_ty(
+        opaque_ty: &chalk_ir::OpaqueTy<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_opaque_ty(opaque_ty, fmt)))
+    }
+
+    fn debug_opaque_ty_id(
+        opaque_ty_id: chalk_ir::OpaqueTyId<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_opaque_ty_id(opaque_ty_id, fmt)))
+    }
+
+    fn debug_ty(ty: &chalk_ir::Ty<Interner>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_ty(ty, fmt)))
+    }
+
+    fn debug_lifetime(
+        lifetime: &chalk_ir::Lifetime<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_lifetime(lifetime, fmt)))
+    }
+
+    fn debug_generic_arg(
+        parameter: &GenericArg<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_generic_arg(parameter, fmt)))
+    }
+
+    fn debug_goal(goal: &Goal<Interner>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_goal(goal, fmt)))
+    }
+
+    fn debug_goals(
+        goals: &chalk_ir::Goals<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_goals(goals, fmt)))
+    }
+
+    fn debug_program_clause_implication(
+        pci: &chalk_ir::ProgramClauseImplication<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_program_clause_implication(pci, fmt)))
+    }
+
+    fn debug_application_ty(
+        application_ty: &chalk_ir::ApplicationTy<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_application_ty(application_ty, fmt)))
+    }
+
+    fn debug_substitution(
+        substitution: &chalk_ir::Substitution<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_substitution(substitution, fmt)))
+    }
+
+    fn debug_separator_trait_ref(
+        separator_trait_ref: &chalk_ir::SeparatorTraitRef<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| {
+            Some(prog?.debug_separator_trait_ref(separator_trait_ref, fmt))
+        })
+    }
+
+    fn debug_fn_def_id(
+        fn_def_id: chalk_ir::FnDefId<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_fn_def_id(fn_def_id, fmt)))
+    }
+    fn debug_const(
+        constant: &chalk_ir::Const<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_const(constant, fmt)))
+    }
+    fn debug_variable_kinds(
+        variable_kinds: &chalk_ir::VariableKinds<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_variable_kinds(variable_kinds, fmt)))
+    }
+    fn debug_variable_kinds_with_angles(
+        variable_kinds: &chalk_ir::VariableKinds<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| {
+            Some(prog?.debug_variable_kinds_with_angles(variable_kinds, fmt))
+        })
+    }
+    fn debug_canonical_var_kinds(
+        canonical_var_kinds: &chalk_ir::CanonicalVarKinds<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| {
+            Some(prog?.debug_canonical_var_kinds(canonical_var_kinds, fmt))
+        })
+    }
+    fn debug_program_clause(
+        clause: &chalk_ir::ProgramClause<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_program_clause(clause, fmt)))
+    }
+    fn debug_program_clauses(
+        clauses: &chalk_ir::ProgramClauses<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_program_clauses(clauses, fmt)))
+    }
+    fn debug_quantified_where_clauses(
+        clauses: &chalk_ir::QuantifiedWhereClauses<Self>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
+        tls::with_current_program(|prog| Some(prog?.debug_quantified_where_clauses(clauses, fmt)))
+    }
+
+    fn intern_ty(&self, ty: chalk_ir::TyData<Self>) -> Box<chalk_ir::TyData<Self>> {
+        Box::new(ty)
+    }
+
+    fn ty_data<'a>(&self, ty: &'a Box<chalk_ir::TyData<Self>>) -> &'a chalk_ir::TyData<Self> {
+        ty
+    }
+
+    fn intern_lifetime(
+        &self,
+        lifetime: chalk_ir::LifetimeData<Self>,
+    ) -> chalk_ir::LifetimeData<Self> {
+        lifetime
+    }
+
+    fn lifetime_data<'a>(
+        &self,
+        lifetime: &'a chalk_ir::LifetimeData<Self>,
+    ) -> &'a chalk_ir::LifetimeData<Self> {
+        lifetime
+    }
+
+    fn intern_const(&self, constant: chalk_ir::ConstData<Self>) -> Arc<chalk_ir::ConstData<Self>> {
+        Arc::new(constant)
+    }
+
+    fn const_data<'a>(
+        &self,
+        constant: &'a Arc<chalk_ir::ConstData<Self>>,
+    ) -> &'a chalk_ir::ConstData<Self> {
+        constant
+    }
+
+    fn const_eq(&self, _ty: &Box<chalk_ir::TyData<Self>>, _c1: &(), _c2: &()) -> bool {
+        true
+    }
+
+    fn intern_generic_arg(
+        &self,
+        parameter: chalk_ir::GenericArgData<Self>,
+    ) -> chalk_ir::GenericArgData<Self> {
+        parameter
+    }
+
+    fn generic_arg_data<'a>(
+        &self,
+        parameter: &'a chalk_ir::GenericArgData<Self>,
+    ) -> &'a chalk_ir::GenericArgData<Self> {
+        parameter
+    }
+
+    fn intern_goal(&self, goal: GoalData<Self>) -> Arc<GoalData<Self>> {
+        Arc::new(goal)
+    }
+
+    fn intern_goals<E>(
+        &self,
+        data: impl IntoIterator<Item = Result<Goal<Self>, E>>,
+    ) -> Result<Self::InternedGoals, E> {
+        data.into_iter().collect()
+    }
+
+    fn goal_data<'a>(&self, goal: &'a Arc<GoalData<Self>>) -> &'a GoalData<Self> {
+        goal
+    }
+
+    fn goals_data<'a>(&self, goals: &'a Vec<Goal<Interner>>) -> &'a [Goal<Interner>] {
+        goals
+    }
+
+    fn intern_substitution<E>(
+        &self,
+        data: impl IntoIterator<Item = Result<GenericArg<Self>, E>>,
+    ) -> Result<Vec<GenericArg<Self>>, E> {
+        data.into_iter().collect()
+    }
+
+    fn substitution_data<'a>(
+        &self,
+        substitution: &'a Vec<GenericArg<Self>>,
+    ) -> &'a [GenericArg<Self>] {
+        substitution
+    }
+
+    fn intern_program_clause(
+        &self,
+        data: chalk_ir::ProgramClauseData<Self>,
+    ) -> chalk_ir::ProgramClauseData<Self> {
+        data
+    }
+
+    fn program_clause_data<'a>(
+        &self,
+        clause: &'a chalk_ir::ProgramClauseData<Self>,
+    ) -> &'a chalk_ir::ProgramClauseData<Self> {
+        clause
+    }
+
+    fn intern_program_clauses<E>(
+        &self,
+        data: impl IntoIterator<Item = Result<chalk_ir::ProgramClause<Self>, E>>,
+    ) -> Result<Arc<[chalk_ir::ProgramClause<Self>]>, E> {
+        data.into_iter().collect()
+    }
+
+    fn program_clauses_data<'a>(
+        &self,
+        clauses: &'a Arc<[chalk_ir::ProgramClause<Self>]>,
+    ) -> &'a [chalk_ir::ProgramClause<Self>] {
+        &clauses
+    }
+
+    fn intern_quantified_where_clauses<E>(
+        &self,
+        data: impl IntoIterator<Item = Result<chalk_ir::QuantifiedWhereClause<Self>, E>>,
+    ) -> Result<Self::InternedQuantifiedWhereClauses, E> {
+        data.into_iter().collect()
+    }
+
+    fn quantified_where_clauses_data<'a>(
+        &self,
+        clauses: &'a Self::InternedQuantifiedWhereClauses,
+    ) -> &'a [chalk_ir::QuantifiedWhereClause<Self>] {
+        clauses
+    }
+
+    fn intern_generic_arg_kinds<E>(
+        &self,
+        data: impl IntoIterator<Item = Result<chalk_ir::VariableKind<Self>, E>>,
+    ) -> Result<Self::InternedVariableKinds, E> {
+        data.into_iter().collect()
+    }
+
+    fn variable_kinds_data<'a>(
+        &self,
+        parameter_kinds: &'a Self::InternedVariableKinds,
+    ) -> &'a [chalk_ir::VariableKind<Self>] {
+        &parameter_kinds
+    }
+
+    fn intern_canonical_var_kinds<E>(
+        &self,
+        data: impl IntoIterator<Item = Result<chalk_ir::CanonicalVarKind<Self>, E>>,
+    ) -> Result<Self::InternedCanonicalVarKinds, E> {
+        data.into_iter().collect()
+    }
+
+    fn canonical_var_kinds_data<'a>(
+        &self,
+        canonical_var_kinds: &'a Self::InternedCanonicalVarKinds,
+    ) -> &'a [chalk_ir::CanonicalVarKind<Self>] {
+        &canonical_var_kinds
+    }
+}
+
+impl chalk_ir::interner::HasInterner for Interner {
+    type Interner = Self;
+}
diff --git a/crates/ra_hir_ty/src/traits/chalk/mapping.rs b/crates/ra_hir_ty/src/traits/chalk/mapping.rs
new file mode 100644
index 000000000..7082cb095
--- /dev/null
+++ b/crates/ra_hir_ty/src/traits/chalk/mapping.rs
@@ -0,0 +1,701 @@
+//! This module contains the implementations of the `ToChalk` trait, which
+//! handles conversion between our data types and their corresponding types in
+//! Chalk (in both directions); plus some helper functions for more specialized
+//! conversions.
+
+use chalk_ir::{
+    cast::Cast, fold::shift::Shift, interner::HasInterner, PlaceholderIndex, Scalar, TypeName,
+    UniverseIndex,
+};
+
+use hir_def::{type_ref::Mutability, AssocContainerId, GenericDefId, Lookup, TypeAliasId};
+use ra_db::salsa::InternKey;
+
+use crate::{
+    db::HirDatabase,
+    primitive::{FloatBitness, FloatTy, IntBitness, IntTy, Signedness, Uncertain},
+    traits::{builtin, AssocTyValue, Canonical, Impl, Obligation},
+    ApplicationTy, CallableDef, GenericPredicate, InEnvironment, ProjectionPredicate, ProjectionTy,
+    Substs, TraitEnvironment, TraitRef, Ty, TypeCtor,
+};
+
+use super::interner::*;
+use super::*;
+
+impl ToChalk for Ty {
+    type Chalk = chalk_ir::Ty<Interner>;
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Ty<Interner> {
+        match self {
+            Ty::Apply(apply_ty) => match apply_ty.ctor {
+                TypeCtor::Ref(m) => ref_to_chalk(db, m, apply_ty.parameters),
+                TypeCtor::FnPtr { num_args: _ } => {
+                    let substitution = apply_ty.parameters.to_chalk(db).shifted_in(&Interner);
+                    chalk_ir::TyData::Function(chalk_ir::Fn { num_binders: 0, substitution })
+                        .intern(&Interner)
+                }
+                _ => {
+                    let name = apply_ty.ctor.to_chalk(db);
+                    let substitution = apply_ty.parameters.to_chalk(db);
+                    chalk_ir::ApplicationTy { name, substitution }.cast(&Interner).intern(&Interner)
+                }
+            },
+            Ty::Projection(proj_ty) => {
+                let associated_ty_id = proj_ty.associated_ty.to_chalk(db);
+                let substitution = proj_ty.parameters.to_chalk(db);
+                chalk_ir::AliasTy::Projection(chalk_ir::ProjectionTy {
+                    associated_ty_id,
+                    substitution,
+                })
+                .cast(&Interner)
+                .intern(&Interner)
+            }
+            Ty::Placeholder(id) => {
+                let interned_id = db.intern_type_param_id(id);
+                PlaceholderIndex {
+                    ui: UniverseIndex::ROOT,
+                    idx: interned_id.as_intern_id().as_usize(),
+                }
+                .to_ty::<Interner>(&Interner)
+            }
+            Ty::Bound(idx) => chalk_ir::TyData::BoundVar(idx).intern(&Interner),
+            Ty::Infer(_infer_ty) => panic!("uncanonicalized infer ty"),
+            Ty::Dyn(predicates) => {
+                let where_clauses = chalk_ir::QuantifiedWhereClauses::from(
+                    &Interner,
+                    predicates.iter().filter(|p| !p.is_error()).cloned().map(|p| p.to_chalk(db)),
+                );
+                let bounded_ty = chalk_ir::DynTy { bounds: make_binders(where_clauses, 1) };
+                chalk_ir::TyData::Dyn(bounded_ty).intern(&Interner)
+            }
+            Ty::Opaque(_) | Ty::Unknown => {
+                let substitution = chalk_ir::Substitution::empty(&Interner);
+                let name = TypeName::Error;
+                chalk_ir::ApplicationTy { name, substitution }.cast(&Interner).intern(&Interner)
+            }
+        }
+    }
+    fn from_chalk(db: &dyn HirDatabase, chalk: chalk_ir::Ty<Interner>) -> Self {
+        match chalk.data(&Interner).clone() {
+            chalk_ir::TyData::Apply(apply_ty) => match apply_ty.name {
+                TypeName::Error => Ty::Unknown,
+                TypeName::Ref(m) => ref_from_chalk(db, m, apply_ty.substitution),
+                _ => {
+                    let ctor = from_chalk(db, apply_ty.name);
+                    let parameters = from_chalk(db, apply_ty.substitution);
+                    Ty::Apply(ApplicationTy { ctor, parameters })
+                }
+            },
+            chalk_ir::TyData::Placeholder(idx) => {
+                assert_eq!(idx.ui, UniverseIndex::ROOT);
+                let interned_id = crate::db::GlobalTypeParamId::from_intern_id(
+                    crate::salsa::InternId::from(idx.idx),
+                );
+                Ty::Placeholder(db.lookup_intern_type_param_id(interned_id))
+            }
+            chalk_ir::TyData::Alias(chalk_ir::AliasTy::Projection(proj)) => {
+                let associated_ty = from_chalk(db, proj.associated_ty_id);
+                let parameters = from_chalk(db, proj.substitution);
+                Ty::Projection(ProjectionTy { associated_ty, parameters })
+            }
+            chalk_ir::TyData::Alias(chalk_ir::AliasTy::Opaque(_)) => unimplemented!(),
+            chalk_ir::TyData::Function(chalk_ir::Fn { num_binders: _, substitution }) => {
+                let parameters: Substs = from_chalk(db, substitution);
+                Ty::Apply(ApplicationTy {
+                    ctor: TypeCtor::FnPtr { num_args: (parameters.len() - 1) as u16 },
+                    parameters,
+                })
+            }
+            chalk_ir::TyData::BoundVar(idx) => Ty::Bound(idx),
+            chalk_ir::TyData::InferenceVar(_iv) => Ty::Unknown,
+            chalk_ir::TyData::Dyn(where_clauses) => {
+                assert_eq!(where_clauses.bounds.binders.len(&Interner), 1);
+                let predicates = where_clauses
+                    .bounds
+                    .skip_binders()
+                    .iter(&Interner)
+                    .map(|c| from_chalk(db, c.clone()))
+                    .collect();
+                Ty::Dyn(predicates)
+            }
+        }
+    }
+}
+
+const LIFETIME_PLACEHOLDER: PlaceholderIndex =
+    PlaceholderIndex { ui: UniverseIndex::ROOT, idx: usize::MAX };
+
+/// We currently don't model lifetimes, but Chalk does. So, we have to insert a
+/// fake lifetime here, because Chalks built-in logic may expect it to be there.
+fn ref_to_chalk(
+    db: &dyn HirDatabase,
+    mutability: Mutability,
+    subst: Substs,
+) -> chalk_ir::Ty<Interner> {
+    let arg = subst[0].clone().to_chalk(db);
+    let lifetime = LIFETIME_PLACEHOLDER.to_lifetime(&Interner);
+    chalk_ir::ApplicationTy {
+        name: TypeName::Ref(mutability.to_chalk(db)),
+        substitution: chalk_ir::Substitution::from(
+            &Interner,
+            vec![lifetime.cast(&Interner), arg.cast(&Interner)],
+        ),
+    }
+    .intern(&Interner)
+}
+
+/// Here we remove the lifetime from the type we got from Chalk.
+fn ref_from_chalk(
+    db: &dyn HirDatabase,
+    mutability: chalk_ir::Mutability,
+    subst: chalk_ir::Substitution<Interner>,
+) -> Ty {
+    let tys = subst
+        .iter(&Interner)
+        .filter_map(|p| Some(from_chalk(db, p.ty(&Interner)?.clone())))
+        .collect();
+    Ty::apply(TypeCtor::Ref(from_chalk(db, mutability)), Substs(tys))
+}
+
+impl ToChalk for Substs {
+    type Chalk = chalk_ir::Substitution<Interner>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Substitution<Interner> {
+        chalk_ir::Substitution::from(&Interner, self.iter().map(|ty| ty.clone().to_chalk(db)))
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, parameters: chalk_ir::Substitution<Interner>) -> Substs {
+        let tys = parameters
+            .iter(&Interner)
+            .map(|p| match p.ty(&Interner) {
+                Some(ty) => from_chalk(db, ty.clone()),
+                None => unimplemented!(),
+            })
+            .collect();
+        Substs(tys)
+    }
+}
+
+impl ToChalk for TraitRef {
+    type Chalk = chalk_ir::TraitRef<Interner>;
+
+    fn to_chalk(self: TraitRef, db: &dyn HirDatabase) -> chalk_ir::TraitRef<Interner> {
+        let trait_id = self.trait_.to_chalk(db);
+        let substitution = self.substs.to_chalk(db);
+        chalk_ir::TraitRef { trait_id, substitution }
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, trait_ref: chalk_ir::TraitRef<Interner>) -> Self {
+        let trait_ = from_chalk(db, trait_ref.trait_id);
+        let substs = from_chalk(db, trait_ref.substitution);
+        TraitRef { trait_, substs }
+    }
+}
+
+impl ToChalk for hir_def::TraitId {
+    type Chalk = TraitId;
+
+    fn to_chalk(self, _db: &dyn HirDatabase) -> TraitId {
+        chalk_ir::TraitId(self.as_intern_id())
+    }
+
+    fn from_chalk(_db: &dyn HirDatabase, trait_id: TraitId) -> hir_def::TraitId {
+        InternKey::from_intern_id(trait_id.0)
+    }
+}
+
+impl ToChalk for TypeCtor {
+    type Chalk = TypeName<Interner>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> TypeName<Interner> {
+        match self {
+            TypeCtor::AssociatedType(type_alias) => {
+                let type_id = type_alias.to_chalk(db);
+                TypeName::AssociatedType(type_id)
+            }
+
+            TypeCtor::Bool => TypeName::Scalar(Scalar::Bool),
+            TypeCtor::Char => TypeName::Scalar(Scalar::Char),
+            TypeCtor::Int(Uncertain::Known(int_ty)) => TypeName::Scalar(int_ty_to_chalk(int_ty)),
+            TypeCtor::Float(Uncertain::Known(FloatTy { bitness: FloatBitness::X32 })) => {
+                TypeName::Scalar(Scalar::Float(chalk_ir::FloatTy::F32))
+            }
+            TypeCtor::Float(Uncertain::Known(FloatTy { bitness: FloatBitness::X64 })) => {
+                TypeName::Scalar(Scalar::Float(chalk_ir::FloatTy::F64))
+            }
+
+            TypeCtor::Tuple { cardinality } => TypeName::Tuple(cardinality.into()),
+            TypeCtor::RawPtr(mutability) => TypeName::Raw(mutability.to_chalk(db)),
+            TypeCtor::Slice => TypeName::Slice,
+            TypeCtor::Ref(mutability) => TypeName::Ref(mutability.to_chalk(db)),
+            TypeCtor::Str => TypeName::Str,
+            TypeCtor::FnDef(callable_def) => {
+                let id = callable_def.to_chalk(db);
+                TypeName::FnDef(id)
+            }
+            TypeCtor::Int(Uncertain::Unknown)
+            | TypeCtor::Float(Uncertain::Unknown)
+            | TypeCtor::Adt(_)
+            | TypeCtor::Array
+            | TypeCtor::FnPtr { .. }
+            | TypeCtor::Never
+            | TypeCtor::Closure { .. } => {
+                // other TypeCtors get interned and turned into a chalk StructId
+                let struct_id = db.intern_type_ctor(self).into();
+                TypeName::Adt(struct_id)
+            }
+        }
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, type_name: TypeName<Interner>) -> TypeCtor {
+        match type_name {
+            TypeName::Adt(struct_id) => db.lookup_intern_type_ctor(struct_id.into()),
+            TypeName::AssociatedType(type_id) => TypeCtor::AssociatedType(from_chalk(db, type_id)),
+            TypeName::OpaqueType(_) => unreachable!(),
+
+            TypeName::Scalar(Scalar::Bool) => TypeCtor::Bool,
+            TypeName::Scalar(Scalar::Char) => TypeCtor::Char,
+            TypeName::Scalar(Scalar::Int(int_ty)) => TypeCtor::Int(Uncertain::Known(IntTy {
+                signedness: Signedness::Signed,
+                bitness: bitness_from_chalk_int(int_ty),
+            })),
+            TypeName::Scalar(Scalar::Uint(uint_ty)) => TypeCtor::Int(Uncertain::Known(IntTy {
+                signedness: Signedness::Unsigned,
+                bitness: bitness_from_chalk_uint(uint_ty),
+            })),
+            TypeName::Scalar(Scalar::Float(chalk_ir::FloatTy::F32)) => {
+                TypeCtor::Float(Uncertain::Known(FloatTy { bitness: FloatBitness::X32 }))
+            }
+            TypeName::Scalar(Scalar::Float(chalk_ir::FloatTy::F64)) => {
+                TypeCtor::Float(Uncertain::Known(FloatTy { bitness: FloatBitness::X64 }))
+            }
+            TypeName::Tuple(cardinality) => TypeCtor::Tuple { cardinality: cardinality as u16 },
+            TypeName::Raw(mutability) => TypeCtor::RawPtr(from_chalk(db, mutability)),
+            TypeName::Slice => TypeCtor::Slice,
+            TypeName::Ref(mutability) => TypeCtor::Ref(from_chalk(db, mutability)),
+            TypeName::Str => TypeCtor::Str,
+
+            TypeName::FnDef(fn_def_id) => {
+                let callable_def = from_chalk(db, fn_def_id);
+                TypeCtor::FnDef(callable_def)
+            }
+
+            TypeName::Error => {
+                // this should not be reached, since we don't represent TypeName::Error with TypeCtor
+                unreachable!()
+            }
+        }
+    }
+}
+
+fn bitness_from_chalk_uint(uint_ty: chalk_ir::UintTy) -> IntBitness {
+    use chalk_ir::UintTy;
+
+    match uint_ty {
+        UintTy::Usize => IntBitness::Xsize,
+        UintTy::U8 => IntBitness::X8,
+        UintTy::U16 => IntBitness::X16,
+        UintTy::U32 => IntBitness::X32,
+        UintTy::U64 => IntBitness::X64,
+        UintTy::U128 => IntBitness::X128,
+    }
+}
+
+fn bitness_from_chalk_int(int_ty: chalk_ir::IntTy) -> IntBitness {
+    use chalk_ir::IntTy;
+
+    match int_ty {
+        IntTy::Isize => IntBitness::Xsize,
+        IntTy::I8 => IntBitness::X8,
+        IntTy::I16 => IntBitness::X16,
+        IntTy::I32 => IntBitness::X32,
+        IntTy::I64 => IntBitness::X64,
+        IntTy::I128 => IntBitness::X128,
+    }
+}
+
+fn int_ty_to_chalk(int_ty: IntTy) -> Scalar {
+    use chalk_ir::{IntTy, UintTy};
+
+    match int_ty.signedness {
+        Signedness::Signed => Scalar::Int(match int_ty.bitness {
+            IntBitness::Xsize => IntTy::Isize,
+            IntBitness::X8 => IntTy::I8,
+            IntBitness::X16 => IntTy::I16,
+            IntBitness::X32 => IntTy::I32,
+            IntBitness::X64 => IntTy::I64,
+            IntBitness::X128 => IntTy::I128,
+        }),
+        Signedness::Unsigned => Scalar::Uint(match int_ty.bitness {
+            IntBitness::Xsize => UintTy::Usize,
+            IntBitness::X8 => UintTy::U8,
+            IntBitness::X16 => UintTy::U16,
+            IntBitness::X32 => UintTy::U32,
+            IntBitness::X64 => UintTy::U64,
+            IntBitness::X128 => UintTy::U128,
+        }),
+    }
+}
+
+impl ToChalk for Mutability {
+    type Chalk = chalk_ir::Mutability;
+    fn to_chalk(self, _db: &dyn HirDatabase) -> Self::Chalk {
+        match self {
+            Mutability::Shared => chalk_ir::Mutability::Not,
+            Mutability::Mut => chalk_ir::Mutability::Mut,
+        }
+    }
+    fn from_chalk(_db: &dyn HirDatabase, chalk: Self::Chalk) -> Self {
+        match chalk {
+            chalk_ir::Mutability::Mut => Mutability::Mut,
+            chalk_ir::Mutability::Not => Mutability::Shared,
+        }
+    }
+}
+
+impl ToChalk for Impl {
+    type Chalk = ImplId;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> ImplId {
+        db.intern_chalk_impl(self).into()
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, impl_id: ImplId) -> Impl {
+        db.lookup_intern_chalk_impl(impl_id.into())
+    }
+}
+
+impl ToChalk for CallableDef {
+    type Chalk = FnDefId;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> FnDefId {
+        db.intern_callable_def(self).into()
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, fn_def_id: FnDefId) -> CallableDef {
+        db.lookup_intern_callable_def(fn_def_id.into())
+    }
+}
+
+impl ToChalk for TypeAliasId {
+    type Chalk = AssocTypeId;
+
+    fn to_chalk(self, _db: &dyn HirDatabase) -> AssocTypeId {
+        chalk_ir::AssocTypeId(self.as_intern_id())
+    }
+
+    fn from_chalk(_db: &dyn HirDatabase, type_alias_id: AssocTypeId) -> TypeAliasId {
+        InternKey::from_intern_id(type_alias_id.0)
+    }
+}
+
+impl ToChalk for AssocTyValue {
+    type Chalk = AssociatedTyValueId;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> AssociatedTyValueId {
+        db.intern_assoc_ty_value(self).into()
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, assoc_ty_value_id: AssociatedTyValueId) -> AssocTyValue {
+        db.lookup_intern_assoc_ty_value(assoc_ty_value_id.into())
+    }
+}
+
+impl ToChalk for GenericPredicate {
+    type Chalk = chalk_ir::QuantifiedWhereClause<Interner>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::QuantifiedWhereClause<Interner> {
+        match self {
+            GenericPredicate::Implemented(trait_ref) => {
+                let chalk_trait_ref = trait_ref.to_chalk(db);
+                let chalk_trait_ref = chalk_trait_ref.shifted_in(&Interner);
+                make_binders(chalk_ir::WhereClause::Implemented(chalk_trait_ref), 0)
+            }
+            GenericPredicate::Projection(projection_pred) => {
+                let ty = projection_pred.ty.to_chalk(db).shifted_in(&Interner);
+                let projection = projection_pred.projection_ty.to_chalk(db).shifted_in(&Interner);
+                let alias = chalk_ir::AliasTy::Projection(projection);
+                make_binders(chalk_ir::WhereClause::AliasEq(chalk_ir::AliasEq { alias, ty }), 0)
+            }
+            GenericPredicate::Error => panic!("tried passing GenericPredicate::Error to Chalk"),
+        }
+    }
+
+    fn from_chalk(
+        db: &dyn HirDatabase,
+        where_clause: chalk_ir::QuantifiedWhereClause<Interner>,
+    ) -> GenericPredicate {
+        // we don't produce any where clauses with binders and can't currently deal with them
+        match where_clause
+            .skip_binders()
+            .shifted_out(&Interner)
+            .expect("unexpected bound vars in where clause")
+        {
+            chalk_ir::WhereClause::Implemented(tr) => {
+                GenericPredicate::Implemented(from_chalk(db, tr))
+            }
+            chalk_ir::WhereClause::AliasEq(projection_eq) => {
+                let projection_ty = from_chalk(
+                    db,
+                    match projection_eq.alias {
+                        chalk_ir::AliasTy::Projection(p) => p,
+                        _ => unimplemented!(),
+                    },
+                );
+                let ty = from_chalk(db, projection_eq.ty);
+                GenericPredicate::Projection(ProjectionPredicate { projection_ty, ty })
+            }
+        }
+    }
+}
+
+impl ToChalk for ProjectionTy {
+    type Chalk = chalk_ir::ProjectionTy<Interner>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::ProjectionTy<Interner> {
+        chalk_ir::ProjectionTy {
+            associated_ty_id: self.associated_ty.to_chalk(db),
+            substitution: self.parameters.to_chalk(db),
+        }
+    }
+
+    fn from_chalk(
+        db: &dyn HirDatabase,
+        projection_ty: chalk_ir::ProjectionTy<Interner>,
+    ) -> ProjectionTy {
+        ProjectionTy {
+            associated_ty: from_chalk(db, projection_ty.associated_ty_id),
+            parameters: from_chalk(db, projection_ty.substitution),
+        }
+    }
+}
+
+impl ToChalk for ProjectionPredicate {
+    type Chalk = chalk_ir::AliasEq<Interner>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::AliasEq<Interner> {
+        chalk_ir::AliasEq {
+            alias: chalk_ir::AliasTy::Projection(self.projection_ty.to_chalk(db)),
+            ty: self.ty.to_chalk(db),
+        }
+    }
+
+    fn from_chalk(_db: &dyn HirDatabase, _normalize: chalk_ir::AliasEq<Interner>) -> Self {
+        unimplemented!()
+    }
+}
+
+impl ToChalk for Obligation {
+    type Chalk = chalk_ir::DomainGoal<Interner>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::DomainGoal<Interner> {
+        match self {
+            Obligation::Trait(tr) => tr.to_chalk(db).cast(&Interner),
+            Obligation::Projection(pr) => pr.to_chalk(db).cast(&Interner),
+        }
+    }
+
+    fn from_chalk(_db: &dyn HirDatabase, _goal: chalk_ir::DomainGoal<Interner>) -> Self {
+        unimplemented!()
+    }
+}
+
+impl<T> ToChalk for Canonical<T>
+where
+    T: ToChalk,
+    T::Chalk: HasInterner<Interner = Interner>,
+{
+    type Chalk = chalk_ir::Canonical<T::Chalk>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Canonical<T::Chalk> {
+        let parameter = chalk_ir::CanonicalVarKind::new(
+            chalk_ir::VariableKind::Ty,
+            chalk_ir::UniverseIndex::ROOT,
+        );
+        let value = self.value.to_chalk(db);
+        chalk_ir::Canonical {
+            value,
+            binders: chalk_ir::CanonicalVarKinds::from(&Interner, vec![parameter; self.num_vars]),
+        }
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, canonical: chalk_ir::Canonical<T::Chalk>) -> Canonical<T> {
+        Canonical {
+            num_vars: canonical.binders.len(&Interner),
+            value: from_chalk(db, canonical.value),
+        }
+    }
+}
+
+impl ToChalk for Arc<TraitEnvironment> {
+    type Chalk = chalk_ir::Environment<Interner>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Environment<Interner> {
+        let mut clauses = Vec::new();
+        for pred in &self.predicates {
+            if pred.is_error() {
+                // for env, we just ignore errors
+                continue;
+            }
+            let program_clause: chalk_ir::ProgramClause<Interner> =
+                pred.clone().to_chalk(db).cast(&Interner);
+            clauses.push(program_clause.into_from_env_clause(&Interner));
+        }
+        chalk_ir::Environment::new(&Interner).add_clauses(&Interner, clauses)
+    }
+
+    fn from_chalk(
+        _db: &dyn HirDatabase,
+        _env: chalk_ir::Environment<Interner>,
+    ) -> Arc<TraitEnvironment> {
+        unimplemented!()
+    }
+}
+
+impl<T: ToChalk> ToChalk for InEnvironment<T>
+where
+    T::Chalk: chalk_ir::interner::HasInterner<Interner = Interner>,
+{
+    type Chalk = chalk_ir::InEnvironment<T::Chalk>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::InEnvironment<T::Chalk> {
+        chalk_ir::InEnvironment {
+            environment: self.environment.to_chalk(db),
+            goal: self.value.to_chalk(db),
+        }
+    }
+
+    fn from_chalk(
+        db: &dyn HirDatabase,
+        in_env: chalk_ir::InEnvironment<T::Chalk>,
+    ) -> InEnvironment<T> {
+        InEnvironment {
+            environment: from_chalk(db, in_env.environment),
+            value: from_chalk(db, in_env.goal),
+        }
+    }
+}
+
+impl ToChalk for builtin::BuiltinImplData {
+    type Chalk = ImplDatum;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> ImplDatum {
+        let impl_type = chalk_rust_ir::ImplType::External;
+        let where_clauses = self.where_clauses.into_iter().map(|w| w.to_chalk(db)).collect();
+
+        let impl_datum_bound =
+            chalk_rust_ir::ImplDatumBound { trait_ref: self.trait_ref.to_chalk(db), where_clauses };
+        let associated_ty_value_ids =
+            self.assoc_ty_values.into_iter().map(|v| v.to_chalk(db)).collect();
+        chalk_rust_ir::ImplDatum {
+            binders: make_binders(impl_datum_bound, self.num_vars),
+            impl_type,
+            polarity: chalk_rust_ir::Polarity::Positive,
+            associated_ty_value_ids,
+        }
+    }
+
+    fn from_chalk(_db: &dyn HirDatabase, _data: ImplDatum) -> Self {
+        unimplemented!()
+    }
+}
+
+impl ToChalk for builtin::BuiltinImplAssocTyValueData {
+    type Chalk = AssociatedTyValue;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> AssociatedTyValue {
+        let ty = self.value.to_chalk(db);
+        let value_bound = chalk_rust_ir::AssociatedTyValueBound { ty };
+
+        chalk_rust_ir::AssociatedTyValue {
+            associated_ty_id: self.assoc_ty_id.to_chalk(db),
+            impl_id: self.impl_.to_chalk(db),
+            value: make_binders(value_bound, self.num_vars),
+        }
+    }
+
+    fn from_chalk(
+        _db: &dyn HirDatabase,
+        _data: AssociatedTyValue,
+    ) -> builtin::BuiltinImplAssocTyValueData {
+        unimplemented!()
+    }
+}
+
+pub(super) fn make_binders<T>(value: T, num_vars: usize) -> chalk_ir::Binders<T>
+where
+    T: HasInterner<Interner = Interner>,
+{
+    chalk_ir::Binders::new(
+        chalk_ir::VariableKinds::from(
+            &Interner,
+            std::iter::repeat(chalk_ir::VariableKind::Ty).take(num_vars),
+        ),
+        value,
+    )
+}
+
+pub(super) fn convert_where_clauses(
+    db: &dyn HirDatabase,
+    def: GenericDefId,
+    substs: &Substs,
+) -> Vec<chalk_ir::QuantifiedWhereClause<Interner>> {
+    let generic_predicates = db.generic_predicates(def);
+    let mut result = Vec::with_capacity(generic_predicates.len());
+    for pred in generic_predicates.iter() {
+        if pred.value.is_error() {
+            // skip errored predicates completely
+            continue;
+        }
+        result.push(pred.clone().subst(substs).to_chalk(db));
+    }
+    result
+}
+
+pub(super) fn generic_predicate_to_inline_bound(
+    db: &dyn HirDatabase,
+    pred: &GenericPredicate,
+    self_ty: &Ty,
+) -> Option<chalk_rust_ir::InlineBound<Interner>> {
+    // An InlineBound is like a GenericPredicate, except the self type is left out.
+    // We don't have a special type for this, but Chalk does.
+    match pred {
+        GenericPredicate::Implemented(trait_ref) => {
+            if &trait_ref.substs[0] != self_ty {
+                // we can only convert predicates back to type bounds if they
+                // have the expected self type
+                return None;
+            }
+            let args_no_self = trait_ref.substs[1..]
+                .iter()
+                .map(|ty| ty.clone().to_chalk(db).cast(&Interner))
+                .collect();
+            let trait_bound =
+                chalk_rust_ir::TraitBound { trait_id: trait_ref.trait_.to_chalk(db), args_no_self };
+            Some(chalk_rust_ir::InlineBound::TraitBound(trait_bound))
+        }
+        GenericPredicate::Projection(proj) => {
+            if &proj.projection_ty.parameters[0] != self_ty {
+                return None;
+            }
+            let trait_ = match proj.projection_ty.associated_ty.lookup(db.upcast()).container {
+                AssocContainerId::TraitId(t) => t,
+                _ => panic!("associated type not in trait"),
+            };
+            let args_no_self = proj.projection_ty.parameters[1..]
+                .iter()
+                .map(|ty| ty.clone().to_chalk(db).cast(&Interner))
+                .collect();
+            let alias_eq_bound = chalk_rust_ir::AliasEqBound {
+                value: proj.ty.clone().to_chalk(db),
+                trait_bound: chalk_rust_ir::TraitBound {
+                    trait_id: trait_.to_chalk(db),
+                    args_no_self,
+                },
+                associated_ty_id: proj.projection_ty.associated_ty.to_chalk(db),
+                parameters: Vec::new(), // FIXME we don't support generic associated types yet
+            };
+            Some(chalk_rust_ir::InlineBound::AliasEqBound(alias_eq_bound))
+        }
+        GenericPredicate::Error => None,
+    }
+}
diff --git a/crates/ra_hir_ty/src/traits/chalk/tls.rs b/crates/ra_hir_ty/src/traits/chalk/tls.rs
index 4867cb17e..d88828c7c 100644
--- a/crates/ra_hir_ty/src/traits/chalk/tls.rs
+++ b/crates/ra_hir_ty/src/traits/chalk/tls.rs
@@ -1,7 +1,7 @@
 //! Implementation of Chalk debug helper functions using TLS.
 use std::fmt;
 
-use chalk_ir::{AliasTy, Goal, Goals, Lifetime, Parameter, ProgramClauseImplication, TypeName};
+use chalk_ir::{AliasTy, GenericArg, Goal, Goals, Lifetime, ProgramClauseImplication, TypeName};
 use itertools::Itertools;
 
 use super::{from_chalk, Interner};
@@ -15,10 +15,10 @@ pub struct DebugContext<'a>(&'a (dyn HirDatabase + 'a));
 impl DebugContext<'_> {
     pub fn debug_struct_id(
         &self,
-        id: super::StructId,
+        id: super::AdtId,
         f: &mut fmt::Formatter<'_>,
     ) -> Result<(), fmt::Error> {
-        let type_ctor: TypeCtor = from_chalk(self.0, TypeName::Struct(id));
+        let type_ctor: TypeCtor = from_chalk(self.0, TypeName::Adt(id));
         match type_ctor {
             TypeCtor::Bool => write!(f, "bool")?,
             TypeCtor::Char => write!(f, "char")?,
@@ -188,9 +188,9 @@ impl DebugContext<'_> {
         write!(fmt, "{:?}", lifetime.data(&Interner))
     }
 
-    pub fn debug_parameter(
+    pub fn debug_generic_arg(
         &self,
-        parameter: &Parameter<Interner>,
+        parameter: &GenericArg<Interner>,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Result<(), fmt::Error> {
         write!(fmt, "{:?}", parameter.data(&Interner).inner_debug())
@@ -244,6 +244,79 @@ impl DebugContext<'_> {
     ) -> Result<(), fmt::Error> {
         write!(fmt, "{:?}", separator_trait_ref.debug(&Interner))
     }
+
+    pub fn debug_fn_def_id(
+        &self,
+        fn_def_id: chalk_ir::FnDefId<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Result<(), fmt::Error> {
+        let def: CallableDef = from_chalk(self.0, fn_def_id);
+        let name = match def {
+            CallableDef::FunctionId(ff) => self.0.function_data(ff).name.clone(),
+            CallableDef::StructId(s) => self.0.struct_data(s).name.clone(),
+            CallableDef::EnumVariantId(e) => {
+                let enum_data = self.0.enum_data(e.parent);
+                enum_data.variants[e.local_id].name.clone()
+            }
+        };
+        match def {
+            CallableDef::FunctionId(_) => write!(fmt, "{{fn {}}}", name),
+            CallableDef::StructId(_) | CallableDef::EnumVariantId(_) => {
+                write!(fmt, "{{ctor {}}}", name)
+            }
+        }
+    }
+
+    pub fn debug_const(
+        &self,
+        _constant: &chalk_ir::Const<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> fmt::Result {
+        write!(fmt, "const")
+    }
+
+    pub fn debug_variable_kinds(
+        &self,
+        variable_kinds: &chalk_ir::VariableKinds<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> fmt::Result {
+        write!(fmt, "{:?}", variable_kinds.as_slice(&Interner))
+    }
+    pub fn debug_variable_kinds_with_angles(
+        &self,
+        variable_kinds: &chalk_ir::VariableKinds<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> fmt::Result {
+        write!(fmt, "{:?}", variable_kinds.inner_debug(&Interner))
+    }
+    pub fn debug_canonical_var_kinds(
+        &self,
+        canonical_var_kinds: &chalk_ir::CanonicalVarKinds<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> fmt::Result {
+        write!(fmt, "{:?}", canonical_var_kinds.as_slice(&Interner))
+    }
+    pub fn debug_program_clause(
+        &self,
+        clause: &chalk_ir::ProgramClause<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> fmt::Result {
+        write!(fmt, "{:?}", clause.data(&Interner))
+    }
+    pub fn debug_program_clauses(
+        &self,
+        clauses: &chalk_ir::ProgramClauses<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> fmt::Result {
+        write!(fmt, "{:?}", clauses.as_slice(&Interner))
+    }
+    pub fn debug_quantified_where_clauses(
+        &self,
+        clauses: &chalk_ir::QuantifiedWhereClauses<Interner>,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> fmt::Result {
+        write!(fmt, "{:?}", clauses.as_slice(&Interner))
+    }
 }
 
 mod unsafe_tls {
diff --git a/crates/ra_ide/src/call_info.rs b/crates/ra_ide/src/call_info.rs
index 780a03c13..aa039e6fc 100644
--- a/crates/ra_ide/src/call_info.rs
+++ b/crates/ra_ide/src/call_info.rs
@@ -5,7 +5,7 @@ use ra_syntax::{
     ast::{self, ArgListOwner},
     match_ast, AstNode, SyntaxNode, SyntaxToken,
 };
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{CallInfo, FilePosition, FunctionSignature};
 
@@ -84,7 +84,7 @@ fn call_info_for_token(sema: &Semantics<RootDatabase>, token: SyntaxToken) -> Op
 
                 let arg_list_range = arg_list.syntax().text_range();
                 if !arg_list_range.contains_inclusive(token.text_range().start()) {
-                    tested_by!(call_info_bad_offset);
+                    mark::hit!(call_info_bad_offset);
                     return None;
                 }
 
@@ -213,7 +213,7 @@ impl CallInfo {
 
 #[cfg(test)]
 mod tests {
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::mock_analysis::single_file_with_position;
 
@@ -529,7 +529,7 @@ By default this method stops actor's `Context`."#
 
     #[test]
     fn call_info_bad_offset() {
-        covers!(call_info_bad_offset);
+        mark::check!(call_info_bad_offset);
         let (analysis, position) = single_file_with_position(
             r#"fn foo(x: u32, y: u32) -> u32 {x + y}
                fn bar() { foo <|> (3, ); }"#,
diff --git a/crates/ra_ide/src/completion.rs b/crates/ra_ide/src/completion.rs
index 8bdc43b1a..191300704 100644
--- a/crates/ra_ide/src/completion.rs
+++ b/crates/ra_ide/src/completion.rs
@@ -59,8 +59,8 @@ pub use crate::completion::{
 /// with ordering of completions (currently this is done by the client).
 pub(crate) fn completions(
     db: &RootDatabase,
-    position: FilePosition,
     config: &CompletionConfig,
+    position: FilePosition,
 ) -> Option<Completions> {
     let ctx = CompletionContext::new(db, position, config)?;
 
diff --git a/crates/ra_ide/src/completion/complete_qualified_path.rs b/crates/ra_ide/src/completion/complete_qualified_path.rs
index db7430454..02ac0166b 100644
--- a/crates/ra_ide/src/completion/complete_qualified_path.rs
+++ b/crates/ra_ide/src/completion/complete_qualified_path.rs
@@ -3,7 +3,7 @@
 use hir::{Adt, HasVisibility, PathResolution, ScopeDef};
 use ra_syntax::AstNode;
 use rustc_hash::FxHashSet;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::completion::{CompletionContext, Completions};
 
@@ -40,7 +40,7 @@ pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                         if let Some(name_ref) = ctx.name_ref_syntax.as_ref() {
                             if name_ref.syntax().text() == name.to_string().as_str() {
                                 // for `use self::foo<|>`, don't suggest `foo` as a completion
-                                tested_by!(dont_complete_current_use);
+                                mark::hit!(dont_complete_current_use);
                                 continue;
                             }
                         }
@@ -147,7 +147,7 @@ pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
 
 #[cfg(test)]
 mod tests {
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
     use insta::assert_debug_snapshot;
@@ -158,7 +158,7 @@ mod tests {
 
     #[test]
     fn dont_complete_current_use() {
-        covers!(dont_complete_current_use);
+        mark::check!(dont_complete_current_use);
         let completions = do_completion(r"use self::foo<|>;", CompletionKind::Reference);
         assert!(completions.is_empty());
     }
diff --git a/crates/ra_ide/src/completion/complete_unqualified_path.rs b/crates/ra_ide/src/completion/complete_unqualified_path.rs
index bd40af1cb..db791660a 100644
--- a/crates/ra_ide/src/completion/complete_unqualified_path.rs
+++ b/crates/ra_ide/src/completion/complete_unqualified_path.rs
@@ -1,7 +1,7 @@
 //! Completion of names from the current scope, e.g. locals and imported items.
 
 use hir::ScopeDef;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::completion::{CompletionContext, Completions};
 use hir::{Adt, ModuleDef, Type};
@@ -30,7 +30,7 @@ pub(super) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
         if ctx.use_item_syntax.is_some() {
             if let (ScopeDef::Unknown, Some(name_ref)) = (&res, &ctx.name_ref_syntax) {
                 if name_ref.syntax().text() == name.to_string().as_str() {
-                    tested_by!(self_fulfilling_completion);
+                    mark::hit!(self_fulfilling_completion);
                     return;
                 }
             }
@@ -66,7 +66,7 @@ fn complete_enum_variants(acc: &mut Completions, ctx: &CompletionContext, ty: &T
 #[cfg(test)]
 mod tests {
     use insta::assert_debug_snapshot;
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::completion::{test_utils::do_completion, CompletionItem, CompletionKind};
 
@@ -76,7 +76,7 @@ mod tests {
 
     #[test]
     fn self_fulfilling_completion() {
-        covers!(self_fulfilling_completion);
+        mark::check!(self_fulfilling_completion);
         assert_debug_snapshot!(
             do_reference_completion(
                 r#"
diff --git a/crates/ra_ide/src/completion/completion_item.rs b/crates/ra_ide/src/completion/completion_item.rs
index 6021f7279..cfb7c1e38 100644
--- a/crates/ra_ide/src/completion/completion_item.rs
+++ b/crates/ra_ide/src/completion/completion_item.rs
@@ -63,8 +63,8 @@ impl fmt::Debug for CompletionItem {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let mut s = f.debug_struct("CompletionItem");
         s.field("label", &self.label()).field("source_range", &self.source_range());
-        if self.text_edit().as_indels().len() == 1 {
-            let atom = &self.text_edit().as_indels()[0];
+        if self.text_edit().len() == 1 {
+            let atom = &self.text_edit().iter().next().unwrap();
             s.field("delete", &atom.delete);
             s.field("insert", &atom.insert);
         } else {
diff --git a/crates/ra_ide/src/completion/presentation.rs b/crates/ra_ide/src/completion/presentation.rs
index 077cf9647..440ffa31d 100644
--- a/crates/ra_ide/src/completion/presentation.rs
+++ b/crates/ra_ide/src/completion/presentation.rs
@@ -3,7 +3,7 @@
 use hir::{Docs, HasAttrs, HasSource, HirDisplay, ModPath, ScopeDef, StructKind, Type};
 use ra_syntax::ast::NameOwner;
 use stdx::SepBy;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{
     completion::{
@@ -121,7 +121,7 @@ impl Completions {
                     _ => false,
                 };
                 if has_non_default_type_params {
-                    tested_by!(inserts_angle_brackets_for_generics);
+                    mark::hit!(inserts_angle_brackets_for_generics);
                     completion_item = completion_item
                         .lookup_by(local_name.clone())
                         .label(format!("{}<…>", local_name))
@@ -176,7 +176,7 @@ impl Completions {
             }
             None if needs_bang => builder.insert_text(format!("{}!", name)),
             _ => {
-                tested_by!(dont_insert_macro_call_parens_unncessary);
+                mark::hit!(dont_insert_macro_call_parens_unncessary);
                 builder.insert_text(name)
             }
         };
@@ -330,14 +330,14 @@ pub(crate) fn compute_score(
     // FIXME: this should not fall back to string equality.
     let ty = &ty.display(ctx.db).to_string();
     let (active_name, active_type) = if let Some(record_field) = &ctx.record_field_syntax {
-        tested_by!(test_struct_field_completion_in_record_lit);
+        mark::hit!(test_struct_field_completion_in_record_lit);
         let (struct_field, _local) = ctx.sema.resolve_record_field(record_field)?;
         (
             struct_field.name(ctx.db).to_string(),
             struct_field.signature_ty(ctx.db).display(ctx.db).to_string(),
         )
     } else if let Some(active_parameter) = &ctx.active_parameter {
-        tested_by!(test_struct_field_completion_in_func_call);
+        mark::hit!(test_struct_field_completion_in_func_call);
         (active_parameter.name.clone(), active_parameter.ty.clone())
     } else {
         return None;
@@ -398,7 +398,7 @@ impl Builder {
             None => return self,
         };
         // If not an import, add parenthesis automatically.
-        tested_by!(inserts_parens_for_function_calls);
+        mark::hit!(inserts_parens_for_function_calls);
 
         let (snippet, label) = if params.is_empty() {
             (format!("{}()$0", name), format!("{}()", name))
@@ -457,7 +457,7 @@ fn guess_macro_braces(macro_name: &str, docs: &str) -> (&'static str, &'static s
 #[cfg(test)]
 mod tests {
     use insta::assert_debug_snapshot;
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::completion::{
         test_utils::{do_completion, do_completion_with_options},
@@ -607,7 +607,7 @@ mod tests {
 
     #[test]
     fn inserts_parens_for_function_calls() {
-        covers!(inserts_parens_for_function_calls);
+        mark::check!(inserts_parens_for_function_calls);
         assert_debug_snapshot!(
             do_reference_completion(
                 r"
@@ -992,7 +992,7 @@ mod tests {
 
     #[test]
     fn inserts_angle_brackets_for_generics() {
-        covers!(inserts_angle_brackets_for_generics);
+        mark::check!(inserts_angle_brackets_for_generics);
         assert_debug_snapshot!(
             do_reference_completion(
                 r"
@@ -1115,7 +1115,7 @@ mod tests {
 
     #[test]
     fn dont_insert_macro_call_parens_unncessary() {
-        covers!(dont_insert_macro_call_parens_unncessary);
+        mark::check!(dont_insert_macro_call_parens_unncessary);
         assert_debug_snapshot!(
             do_reference_completion(
                 r"
@@ -1181,7 +1181,7 @@ mod tests {
 
     #[test]
     fn test_struct_field_completion_in_func_call() {
-        covers!(test_struct_field_completion_in_func_call);
+        mark::check!(test_struct_field_completion_in_func_call);
         assert_debug_snapshot!(
         do_reference_completion(
                 r"
@@ -1271,7 +1271,7 @@ mod tests {
 
     #[test]
     fn test_struct_field_completion_in_record_lit() {
-        covers!(test_struct_field_completion_in_record_lit);
+        mark::check!(test_struct_field_completion_in_record_lit);
         assert_debug_snapshot!(
         do_reference_completion(
                 r"
diff --git a/crates/ra_ide/src/completion/test_utils.rs b/crates/ra_ide/src/completion/test_utils.rs
index eb90b5279..bf22452a2 100644
--- a/crates/ra_ide/src/completion/test_utils.rs
+++ b/crates/ra_ide/src/completion/test_utils.rs
@@ -20,7 +20,7 @@ pub(crate) fn do_completion_with_options(
     } else {
         single_file_with_position(code)
     };
-    let completions = analysis.completions(position, options).unwrap().unwrap();
+    let completions = analysis.completions(options, position).unwrap().unwrap();
     let completion_items: Vec<CompletionItem> = completions.into();
     let mut kind_completions: Vec<CompletionItem> =
         completion_items.into_iter().filter(|c| c.completion_kind == kind).collect();
diff --git a/crates/ra_ide/src/diagnostics.rs b/crates/ra_ide/src/diagnostics.rs
index 87a0b80f1..3d83c0f71 100644
--- a/crates/ra_ide/src/diagnostics.rs
+++ b/crates/ra_ide/src/diagnostics.rs
@@ -21,7 +21,7 @@ use ra_syntax::{
 };
 use ra_text_edit::{TextEdit, TextEditBuilder};
 
-use crate::{Diagnostic, FileId, FileSystemEdit, SourceChange, SourceFileEdit};
+use crate::{Diagnostic, FileId, FileSystemEdit, Fix, SourceChange, SourceFileEdit};
 
 #[derive(Debug, Copy, Clone)]
 pub enum Severity {
@@ -63,8 +63,8 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
             .parent()
             .unwrap_or_else(|| RelativePath::new(""))
             .join(&d.candidate);
-        let create_file = FileSystemEdit::CreateFile { source_root, path };
-        let fix = SourceChange::file_system_edit("Create module", create_file);
+        let fix =
+            Fix::new("Create module", FileSystemEdit::CreateFile { source_root, path }.into());
         res.borrow_mut().push(Diagnostic {
             range: sema.diagnostics_range(d).range,
             message: d.message(),
@@ -88,14 +88,12 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
                 field_list = field_list.append_field(&field);
             }
 
-            let mut builder = TextEditBuilder::default();
-            algo::diff(&d.ast(db).syntax(), &field_list.syntax()).into_text_edit(&mut builder);
-
-            Some(SourceChange::source_file_edit_from(
-                "Fill struct fields",
-                file_id,
-                builder.finish(),
-            ))
+            let edit = {
+                let mut builder = TextEditBuilder::default();
+                algo::diff(&d.ast(db).syntax(), &field_list.syntax()).into_text_edit(&mut builder);
+                builder.finish()
+            };
+            Some(Fix::new("Fill struct fields", SourceFileEdit { file_id, edit }.into()))
         };
 
         res.borrow_mut().push(Diagnostic {
@@ -117,7 +115,8 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
         let node = d.ast(db);
         let replacement = format!("Ok({})", node.syntax());
         let edit = TextEdit::replace(node.syntax().text_range(), replacement);
-        let fix = SourceChange::source_file_edit_from("Wrap with ok", file_id, edit);
+        let source_change = SourceChange::source_file_edit_from(file_id, edit);
+        let fix = Fix::new("Wrap with ok", source_change);
         res.borrow_mut().push(Diagnostic {
             range: sema.diagnostics_range(d).range,
             message: d.message(),
@@ -154,9 +153,9 @@ fn check_unnecessary_braces_in_use_statement(
             range,
             message: "Unnecessary braces in use statement".to_string(),
             severity: Severity::WeakWarning,
-            fix: Some(SourceChange::source_file_edit(
+            fix: Some(Fix::new(
                 "Remove unnecessary braces",
-                SourceFileEdit { file_id, edit },
+                SourceFileEdit { file_id, edit }.into(),
             )),
         });
     }
@@ -198,9 +197,9 @@ fn check_struct_shorthand_initialization(
                     range: record_field.syntax().text_range(),
                     message: "Shorthand struct initialization".to_string(),
                     severity: Severity::WeakWarning,
-                    fix: Some(SourceChange::source_file_edit(
+                    fix: Some(Fix::new(
                         "Use struct shorthand initialization",
-                        SourceFileEdit { file_id, edit },
+                        SourceFileEdit { file_id, edit }.into(),
                     )),
                 });
             }
@@ -240,7 +239,7 @@ mod tests {
         let diagnostic =
             diagnostics.pop().unwrap_or_else(|| panic!("no diagnostics for:\n{}\n", before));
         let mut fix = diagnostic.fix.unwrap();
-        let edit = fix.source_file_edits.pop().unwrap().edit;
+        let edit = fix.source_change.source_file_edits.pop().unwrap().edit;
         let actual = {
             let mut actual = before.to_string();
             edit.apply(&mut actual);
@@ -258,7 +257,7 @@ mod tests {
         let (analysis, file_position) = analysis_and_position(fixture);
         let diagnostic = analysis.diagnostics(file_position.file_id).unwrap().pop().unwrap();
         let mut fix = diagnostic.fix.unwrap();
-        let edit = fix.source_file_edits.pop().unwrap().edit;
+        let edit = fix.source_change.source_file_edits.pop().unwrap().edit;
         let target_file_contents = analysis.file_text(file_position.file_id).unwrap();
         let actual = {
             let mut actual = target_file_contents.to_string();
@@ -295,7 +294,7 @@ mod tests {
         let (analysis, file_id) = single_file(before);
         let diagnostic = analysis.diagnostics(file_id).unwrap().pop().unwrap();
         let mut fix = diagnostic.fix.unwrap();
-        let edit = fix.source_file_edits.pop().unwrap().edit;
+        let edit = fix.source_change.source_file_edits.pop().unwrap().edit;
         let actual = {
             let mut actual = before.to_string();
             edit.apply(&mut actual);
@@ -616,22 +615,24 @@ mod tests {
             Diagnostic {
                 message: "unresolved module",
                 range: 0..8,
+                severity: Error,
                 fix: Some(
-                    SourceChange {
+                    Fix {
                         label: "Create module",
-                        source_file_edits: [],
-                        file_system_edits: [
-                            CreateFile {
-                                source_root: SourceRootId(
-                                    0,
-                                ),
-                                path: "foo.rs",
-                            },
-                        ],
-                        cursor_position: None,
+                        source_change: SourceChange {
+                            source_file_edits: [],
+                            file_system_edits: [
+                                CreateFile {
+                                    source_root: SourceRootId(
+                                        0,
+                                    ),
+                                    path: "foo.rs",
+                                },
+                            ],
+                            is_snippet: false,
+                        },
                     },
                 ),
-                severity: Error,
             },
         ]
         "###);
@@ -665,29 +666,31 @@ mod tests {
             Diagnostic {
                 message: "Missing structure fields:\n- b",
                 range: 224..233,
+                severity: Error,
                 fix: Some(
-                    SourceChange {
+                    Fix {
                         label: "Fill struct fields",
-                        source_file_edits: [
-                            SourceFileEdit {
-                                file_id: FileId(
-                                    1,
-                                ),
-                                edit: TextEdit {
-                                    indels: [
-                                        Indel {
-                                            insert: "{a:42, b: ()}",
-                                            delete: 3..9,
-                                        },
-                                    ],
+                        source_change: SourceChange {
+                            source_file_edits: [
+                                SourceFileEdit {
+                                    file_id: FileId(
+                                        1,
+                                    ),
+                                    edit: TextEdit {
+                                        indels: [
+                                            Indel {
+                                                insert: "{a:42, b: ()}",
+                                                delete: 3..9,
+                                            },
+                                        ],
+                                    },
                                 },
-                            },
-                        ],
-                        file_system_edits: [],
-                        cursor_position: None,
+                            ],
+                            file_system_edits: [],
+                            is_snippet: false,
+                        },
                     },
                 ),
-                severity: Error,
             },
         ]
         "###);
diff --git a/crates/ra_ide/src/display.rs b/crates/ra_ide/src/display.rs
index 722092de9..8bb312156 100644
--- a/crates/ra_ide/src/display.rs
+++ b/crates/ra_ide/src/display.rs
@@ -79,14 +79,14 @@ pub(crate) fn rust_code_markup_with_doc(
     doc: Option<&str>,
     mod_path: Option<&str>,
 ) -> String {
-    let mut buf = "```rust\n".to_owned();
+    let mut buf = String::new();
 
     if let Some(mod_path) = mod_path {
         if !mod_path.is_empty() {
-            format_to!(buf, "{}\n", mod_path);
+            format_to!(buf, "{}\n___\n\n", mod_path);
         }
     }
-    format_to!(buf, "{}\n```", code);
+    format_to!(buf, "```rust\n{}\n```", code);
 
     if let Some(doc) = doc {
         format_to!(buf, "\n\n{}", doc);
diff --git a/crates/ra_ide/src/goto_definition.rs b/crates/ra_ide/src/goto_definition.rs
index 150895abb..90e85d419 100644
--- a/crates/ra_ide/src/goto_definition.rs
+++ b/crates/ra_ide/src/goto_definition.rs
@@ -93,7 +93,7 @@ pub(crate) fn reference_definition(
 
 #[cfg(test)]
 mod tests {
-    use test_utils::{assert_eq_text, covers};
+    use test_utils::assert_eq_text;
 
     use crate::mock_analysis::analysis_and_position;
 
@@ -208,7 +208,6 @@ mod tests {
 
     #[test]
     fn goto_def_for_macros() {
-        covers!(ra_ide_db::goto_def_for_macros);
         check_goto(
             "
             //- /lib.rs
@@ -225,7 +224,6 @@ mod tests {
 
     #[test]
     fn goto_def_for_macros_from_other_crates() {
-        covers!(ra_ide_db::goto_def_for_macros);
         check_goto(
             "
             //- /lib.rs
@@ -245,7 +243,6 @@ mod tests {
 
     #[test]
     fn goto_def_for_use_alias() {
-        covers!(ra_ide_db::goto_def_for_use_alias);
         check_goto(
             "
             //- /lib.rs
@@ -370,7 +367,6 @@ mod tests {
 
     #[test]
     fn goto_def_for_methods() {
-        covers!(ra_ide_db::goto_def_for_methods);
         check_goto(
             "
             //- /lib.rs
@@ -390,7 +386,6 @@ mod tests {
 
     #[test]
     fn goto_def_for_fields() {
-        covers!(ra_ide_db::goto_def_for_fields);
         check_goto(
             r"
             //- /lib.rs
@@ -409,7 +404,6 @@ mod tests {
 
     #[test]
     fn goto_def_for_record_fields() {
-        covers!(ra_ide_db::goto_def_for_record_fields);
         check_goto(
             r"
             //- /lib.rs
@@ -430,7 +424,6 @@ mod tests {
 
     #[test]
     fn goto_def_for_record_pat_fields() {
-        covers!(ra_ide_db::goto_def_for_record_field_pats);
         check_goto(
             r"
             //- /lib.rs
@@ -873,7 +866,6 @@ mod tests {
 
     #[test]
     fn goto_def_for_field_init_shorthand() {
-        covers!(ra_ide_db::goto_def_for_field_init_shorthand);
         check_goto(
             "
             //- /lib.rs
diff --git a/crates/ra_ide/src/hover.rs b/crates/ra_ide/src/hover.rs
index befa977c7..1f4f6b848 100644
--- a/crates/ra_ide/src/hover.rs
+++ b/crates/ra_ide/src/hover.rs
@@ -405,7 +405,7 @@ mod tests {
                 };
             }
         "#,
-            &["Foo\nfield_a: u32"],
+            &["Foo\n___\n\n```rust\nfield_a: u32"],
         );
 
         // Hovering over the field in the definition
@@ -422,7 +422,7 @@ mod tests {
                 };
             }
         "#,
-            &["Foo\nfield_a: u32"],
+            &["Foo\n___\n\n```rust\nfield_a: u32"],
         );
     }
 
@@ -475,7 +475,7 @@ fn main() {
             ",
         );
         let hover = analysis.hover(position).unwrap().unwrap();
-        assert_eq!(trim_markup_opt(hover.info.first()), Some("Option\nSome"));
+        assert_eq!(trim_markup_opt(hover.info.first()), Some("Option\n___\n\n```rust\nSome"));
 
         let (analysis, position) = single_file_with_position(
             "
@@ -503,6 +503,9 @@ fn main() {
         "#,
             &["
 Option
+___
+
+```rust
 None
 ```
 
@@ -524,6 +527,9 @@ The None variant
         "#,
             &["
 Option
+___
+
+```rust
 Some
 ```
 
@@ -606,7 +612,10 @@ fn func(foo: i32) { if true { <|>foo; }; }
             ",
         );
         let hover = analysis.hover(position).unwrap().unwrap();
-        assert_eq!(trim_markup_opt(hover.info.first()), Some("wrapper::Thing\nfn new() -> Thing"));
+        assert_eq!(
+            trim_markup_opt(hover.info.first()),
+            Some("wrapper::Thing\n___\n\n```rust\nfn new() -> Thing")
+        );
     }
 
     #[test]
diff --git a/crates/ra_ide/src/join_lines.rs b/crates/ra_ide/src/join_lines.rs
index d3af780c4..af1ade8a1 100644
--- a/crates/ra_ide/src/join_lines.rs
+++ b/crates/ra_ide/src/join_lines.rs
@@ -166,16 +166,28 @@ fn is_trailing_comma(left: SyntaxKind, right: SyntaxKind) -> bool {
 
 #[cfg(test)]
 mod tests {
-    use crate::test_utils::{assert_eq_text, check_action, extract_range};
+    use ra_syntax::SourceFile;
+    use test_utils::{add_cursor, assert_eq_text, extract_offset, extract_range};
 
     use super::*;
 
     fn check_join_lines(before: &str, after: &str) {
-        check_action(before, after, |file, offset| {
-            let range = TextRange::empty(offset);
-            let res = join_lines(file, range);
-            Some(res)
-        })
+        let (before_cursor_pos, before) = extract_offset(before);
+        let file = SourceFile::parse(&before).ok().unwrap();
+
+        let range = TextRange::empty(before_cursor_pos);
+        let result = join_lines(&file, range);
+
+        let actual = {
+            let mut actual = before.to_string();
+            result.apply(&mut actual);
+            actual
+        };
+        let actual_cursor_pos = result
+            .apply_to_offset(before_cursor_pos)
+            .expect("cursor position is affected by the edit");
+        let actual = add_cursor(&actual, actual_cursor_pos);
+        assert_eq_text!(after, &actual);
     }
 
     #[test]
diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index 78149ddfc..5ac002d82 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -42,11 +42,6 @@ mod inlay_hints;
 mod expand_macro;
 mod ssr;
 
-#[cfg(test)]
-mod marks;
-#[cfg(test)]
-mod test_utils;
-
 use std::sync::Arc;
 
 use ra_cfg::CfgOptions;
@@ -82,19 +77,19 @@ pub use crate::{
 };
 
 pub use hir::Documentation;
-pub use ra_assists::AssistId;
+pub use ra_assists::{AssistConfig, AssistId};
 pub use ra_db::{
     Canceled, CrateGraph, CrateId, Edition, FileId, FilePosition, FileRange, SourceRootId,
 };
 pub use ra_ide_db::{
     change::{AnalysisChange, LibraryData},
     line_index::{LineCol, LineIndex},
-    line_index_utils::translate_offset_with_edit,
     search::SearchScope,
     source_change::{FileSystemEdit, SourceChange, SourceFileEdit},
     symbol_index::Query,
     RootDatabase,
 };
+pub use ra_text_edit::{Indel, TextEdit};
 
 pub type Cancelable<T> = Result<T, Canceled>;
 
@@ -102,8 +97,22 @@ pub type Cancelable<T> = Result<T, Canceled>;
 pub struct Diagnostic {
     pub message: String,
     pub range: TextRange,
-    pub fix: Option<SourceChange>,
     pub severity: Severity,
+    pub fix: Option<Fix>,
+}
+
+#[derive(Debug)]
+pub struct Fix {
+    pub label: String,
+    pub source_change: SourceChange,
+}
+
+impl Fix {
+    pub fn new(label: impl Into<String>, source_change: SourceChange) -> Self {
+        let label = label.into();
+        assert!(label.starts_with(char::is_uppercase) && !label.ends_with('.'));
+        Self { label, source_change }
+    }
 }
 
 /// Info associated with a text range.
@@ -291,14 +300,10 @@ impl Analysis {
 
     /// Returns an edit to remove all newlines in the range, cleaning up minor
     /// stuff like trailing commas.
-    pub fn join_lines(&self, frange: FileRange) -> Cancelable<SourceChange> {
+    pub fn join_lines(&self, frange: FileRange) -> Cancelable<TextEdit> {
         self.with_db(|db| {
             let parse = db.parse(frange.file_id);
-            let file_edit = SourceFileEdit {
-                file_id: frange.file_id,
-                edit: join_lines::join_lines(&parse.tree(), frange.range),
-            };
-            SourceChange::source_file_edit("Join lines", file_edit)
+            join_lines::join_lines(&parse.tree(), frange.range)
         })
     }
 
@@ -458,17 +463,17 @@ impl Analysis {
     /// Computes completions at the given position.
     pub fn completions(
         &self,
-        position: FilePosition,
         config: &CompletionConfig,
+        position: FilePosition,
     ) -> Cancelable<Option<Vec<CompletionItem>>> {
-        self.with_db(|db| completion::completions(db, position, config).map(Into::into))
+        self.with_db(|db| completion::completions(db, config, position).map(Into::into))
     }
 
     /// Computes assists (aka code actions aka intentions) for the given
     /// position.
-    pub fn assists(&self, frange: FileRange) -> Cancelable<Vec<Assist>> {
+    pub fn assists(&self, config: &AssistConfig, frange: FileRange) -> Cancelable<Vec<Assist>> {
         self.with_db(|db| {
-            ra_assists::Assist::resolved(db, frange)
+            ra_assists::Assist::resolved(db, config, frange)
                 .into_iter()
                 .map(|assist| Assist {
                     id: assist.assist.id,
@@ -502,7 +507,7 @@ impl Analysis {
     ) -> Cancelable<Result<SourceChange, SsrError>> {
         self.with_db(|db| {
             let edits = ssr::parse_search_replace(query, parse_only, db)?;
-            Ok(SourceChange::source_file_edits("Structural Search Replace", edits))
+            Ok(SourceChange::source_file_edits(edits))
         })
     }
 
diff --git a/crates/ra_ide/src/marks.rs b/crates/ra_ide/src/marks.rs
deleted file mode 100644
index 51ca4dde3..000000000
--- a/crates/ra_ide/src/marks.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-//! See test_utils/src/marks.rs
-
-test_utils::marks!(
-    inserts_angle_brackets_for_generics
-    inserts_parens_for_function_calls
-    call_info_bad_offset
-    dont_complete_current_use
-    test_resolve_parent_module_on_module_decl
-    search_filters_by_range
-    dont_insert_macro_call_parens_unncessary
-    self_fulfilling_completion
-    test_struct_field_completion_in_func_call
-    test_struct_field_completion_in_record_lit
-    test_rename_struct_field_for_shorthand
-    test_rename_local_for_field_shorthand
-);
diff --git a/crates/ra_ide/src/parent_module.rs b/crates/ra_ide/src/parent_module.rs
index aaf4460df..a083fb1eb 100644
--- a/crates/ra_ide/src/parent_module.rs
+++ b/crates/ra_ide/src/parent_module.rs
@@ -7,7 +7,7 @@ use ra_syntax::{
     algo::find_node_at_offset,
     ast::{self, AstNode},
 };
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::NavigationTarget;
 
@@ -25,7 +25,7 @@ pub(crate) fn parent_module(db: &RootDatabase, position: FilePosition) -> Vec<Na
             .item_list()
             .map_or(false, |it| it.syntax().text_range().contains_inclusive(position.offset))
         {
-            tested_by!(test_resolve_parent_module_on_module_decl);
+            mark::hit!(test_resolve_parent_module_on_module_decl);
             module = m.syntax().ancestors().skip(1).find_map(ast::Module::cast);
         }
     }
@@ -57,7 +57,7 @@ pub(crate) fn crate_for(db: &RootDatabase, file_id: FileId) -> Vec<CrateId> {
 mod tests {
     use ra_cfg::CfgOptions;
     use ra_db::Env;
-    use test_utils::covers;
+    use test_utils::mark;
 
     use crate::{
         mock_analysis::{analysis_and_position, MockAnalysis},
@@ -81,7 +81,7 @@ mod tests {
 
     #[test]
     fn test_resolve_parent_module_on_module_decl() {
-        covers!(test_resolve_parent_module_on_module_decl);
+        mark::check!(test_resolve_parent_module_on_module_decl);
         let (analysis, pos) = analysis_and_position(
             "
             //- /lib.rs
diff --git a/crates/ra_ide/src/references.rs b/crates/ra_ide/src/references.rs
index 074284b42..96444bf6a 100644
--- a/crates/ra_ide/src/references.rs
+++ b/crates/ra_ide/src/references.rs
@@ -190,8 +190,6 @@ fn get_struct_def_name_for_struct_literal_search(
 
 #[cfg(test)]
 mod tests {
-    use test_utils::covers;
-
     use crate::{
         mock_analysis::{analysis_and_position, single_file_with_position, MockAnalysis},
         Declaration, Reference, ReferenceSearchResult, SearchScope,
@@ -301,7 +299,6 @@ mod tests {
 
     #[test]
     fn search_filters_by_range() {
-        covers!(ra_ide_db::search_filters_by_range);
         let code = r#"
             fn foo() {
                 let spam<|> = 92;
diff --git a/crates/ra_ide/src/references/rename.rs b/crates/ra_ide/src/references/rename.rs
index 410dae75c..28c6349b1 100644
--- a/crates/ra_ide/src/references/rename.rs
+++ b/crates/ra_ide/src/references/rename.rs
@@ -9,7 +9,7 @@ use ra_syntax::{
 };
 use ra_text_edit::TextEdit;
 use std::convert::TryInto;
-use test_utils::tested_by;
+use test_utils::mark;
 
 use crate::{
     references::find_all_refs, FilePosition, FileSystemEdit, RangeInfo, Reference, ReferenceKind,
@@ -57,13 +57,13 @@ fn source_edit_from_reference(reference: Reference, new_name: &str) -> SourceFil
     let file_id = reference.file_range.file_id;
     let range = match reference.kind {
         ReferenceKind::FieldShorthandForField => {
-            tested_by!(test_rename_struct_field_for_shorthand);
+            mark::hit!(test_rename_struct_field_for_shorthand);
             replacement_text.push_str(new_name);
             replacement_text.push_str(": ");
             TextRange::new(reference.file_range.range.start(), reference.file_range.range.start())
         }
         ReferenceKind::FieldShorthandForLocal => {
-            tested_by!(test_rename_local_for_field_shorthand);
+            mark::hit!(test_rename_local_for_field_shorthand);
             replacement_text.push_str(": ");
             replacement_text.push_str(new_name);
             TextRange::new(reference.file_range.range.end(), reference.file_range.range.end())
@@ -128,7 +128,7 @@ fn rename_mod(
         source_file_edits.extend(ref_edits);
     }
 
-    Some(SourceChange::from_edits("Rename", source_file_edits, file_system_edits))
+    Some(SourceChange::from_edits(source_file_edits, file_system_edits))
 }
 
 fn rename_to_self(db: &RootDatabase, position: FilePosition) -> Option<RangeInfo<SourceChange>> {
@@ -171,7 +171,7 @@ fn rename_to_self(db: &RootDatabase, position: FilePosition) -> Option<RangeInfo
         ),
     });
 
-    Some(RangeInfo::new(range, SourceChange::source_file_edits("Rename", edits)))
+    Some(RangeInfo::new(range, SourceChange::source_file_edits(edits)))
 }
 
 fn text_edit_from_self_param(
@@ -234,7 +234,7 @@ fn rename_self_to_param(
     let range = ast::SelfParam::cast(self_token.parent())
         .map_or(self_token.text_range(), |p| p.syntax().text_range());
 
-    Some(RangeInfo::new(range, SourceChange::source_file_edits("Rename", edits)))
+    Some(RangeInfo::new(range, SourceChange::source_file_edits(edits)))
 }
 
 fn rename_reference(
@@ -253,14 +253,14 @@ fn rename_reference(
         return None;
     }
 
-    Some(RangeInfo::new(range, SourceChange::source_file_edits("Rename", edit)))
+    Some(RangeInfo::new(range, SourceChange::source_file_edits(edit)))
 }
 
 #[cfg(test)]
 mod tests {
     use insta::assert_debug_snapshot;
     use ra_text_edit::TextEditBuilder;
-    use test_utils::{assert_eq_text, covers};
+    use test_utils::{assert_eq_text, mark};
 
     use crate::{
         mock_analysis::analysis_and_position, mock_analysis::single_file_with_position, FileId,
@@ -492,7 +492,7 @@ mod tests {
 
     #[test]
     fn test_rename_struct_field_for_shorthand() {
-        covers!(test_rename_struct_field_for_shorthand);
+        mark::check!(test_rename_struct_field_for_shorthand);
         test_rename(
             r#"
     struct Foo {
@@ -522,7 +522,7 @@ mod tests {
 
     #[test]
     fn test_rename_local_for_field_shorthand() {
-        covers!(test_rename_local_for_field_shorthand);
+        mark::check!(test_rename_local_for_field_shorthand);
         test_rename(
             r#"
     struct Foo {
@@ -642,7 +642,6 @@ mod tests {
             RangeInfo {
                 range: 4..7,
                 info: SourceChange {
-                    label: "Rename",
                     source_file_edits: [
                         SourceFileEdit {
                             file_id: FileId(
@@ -669,7 +668,7 @@ mod tests {
                             dst_path: "bar/foo2.rs",
                         },
                     ],
-                    cursor_position: None,
+                    is_snippet: false,
                 },
             },
         )
@@ -694,7 +693,6 @@ mod tests {
             RangeInfo {
                 range: 4..7,
                 info: SourceChange {
-                    label: "Rename",
                     source_file_edits: [
                         SourceFileEdit {
                             file_id: FileId(
@@ -721,7 +719,7 @@ mod tests {
                             dst_path: "foo2/mod.rs",
                         },
                     ],
-                    cursor_position: None,
+                    is_snippet: false,
                 },
             },
         )
@@ -777,7 +775,6 @@ mod tests {
             RangeInfo {
                 range: 8..11,
                 info: SourceChange {
-                    label: "Rename",
                     source_file_edits: [
                         SourceFileEdit {
                             file_id: FileId(
@@ -817,7 +814,7 @@ mod tests {
                             dst_path: "bar/foo2.rs",
                         },
                     ],
-                    cursor_position: None,
+                    is_snippet: false,
                 },
             },
         )
@@ -983,8 +980,8 @@ mod tests {
         if let Some(change) = source_change {
             for edit in change.info.source_file_edits {
                 file_id = Some(edit.file_id);
-                for indel in edit.edit.as_indels() {
-                    text_edit_builder.replace(indel.delete, indel.insert.clone());
+                for indel in edit.edit.into_iter() {
+                    text_edit_builder.replace(indel.delete, indel.insert);
                 }
             }
         }
diff --git a/crates/ra_ide/src/runnables.rs b/crates/ra_ide/src/runnables.rs
index fa8a9d92c..131b8f307 100644
--- a/crates/ra_ide/src/runnables.rs
+++ b/crates/ra_ide/src/runnables.rs
@@ -1,6 +1,6 @@
 //! FIXME: write short doc here
 
-use hir::Semantics;
+use hir::{AsAssocItem, Semantics};
 use itertools::Itertools;
 use ra_ide_db::RootDatabase;
 use ra_syntax::{
@@ -65,14 +65,36 @@ fn runnable_fn(sema: &Semantics<RootDatabase>, fn_def: ast::FnDef) -> Option<Run
         RunnableKind::Bin
     } else {
         let test_id = if let Some(module) = sema.to_def(&fn_def).map(|def| def.module(sema.db)) {
-            let path = module
+            let def = sema.to_def(&fn_def)?;
+            let impl_trait_name =
+                def.as_assoc_item(sema.db).and_then(|assoc_item| {
+                    match assoc_item.container(sema.db) {
+                        hir::AssocItemContainer::Trait(trait_item) => {
+                            Some(trait_item.name(sema.db).to_string())
+                        }
+                        hir::AssocItemContainer::ImplDef(impl_def) => impl_def
+                            .target_ty(sema.db)
+                            .as_adt()
+                            .map(|adt| adt.name(sema.db).to_string()),
+                    }
+                });
+
+            let path_iter = module
                 .path_to_root(sema.db)
                 .into_iter()
                 .rev()
                 .filter_map(|it| it.name(sema.db))
-                .map(|name| name.to_string())
-                .chain(std::iter::once(name_string))
-                .join("::");
+                .map(|name| name.to_string());
+
+            let path = if let Some(impl_trait_name) = impl_trait_name {
+                path_iter
+                    .chain(std::iter::once(impl_trait_name))
+                    .chain(std::iter::once(name_string))
+                    .join("::")
+            } else {
+                path_iter.chain(std::iter::once(name_string)).join("::")
+            };
+
             TestId::Path(path)
         } else {
             TestId::Name(name_string)
@@ -238,6 +260,44 @@ mod tests {
     }
 
     #[test]
+    fn test_runnables_doc_test_in_impl() {
+        let (analysis, pos) = analysis_and_position(
+            r#"
+        //- /lib.rs
+        <|> //empty
+        fn main() {}
+
+        struct Data;
+        impl Data {
+            /// ```
+            /// let x = 5;
+            /// ```
+            fn foo() {}
+        }
+        "#,
+        );
+        let runnables = analysis.runnables(pos.file_id).unwrap();
+        assert_debug_snapshot!(&runnables,
+        @r###"
+        [
+            Runnable {
+                range: 1..21,
+                kind: Bin,
+            },
+            Runnable {
+                range: 51..105,
+                kind: DocTest {
+                    test_id: Path(
+                        "Data::foo",
+                    ),
+                },
+            },
+        ]
+        "###
+                );
+    }
+
+    #[test]
     fn test_runnables_module() {
         let (analysis, pos) = analysis_and_position(
             r#"
diff --git a/crates/ra_ide/src/test_utils.rs b/crates/ra_ide/src/test_utils.rs
deleted file mode 100644
index 48c8fd1f4..000000000
--- a/crates/ra_ide/src/test_utils.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-//! FIXME: write short doc here
-
-use ra_syntax::{SourceFile, TextSize};
-use ra_text_edit::TextEdit;
-
-pub use test_utils::*;
-
-pub fn check_action<F: Fn(&SourceFile, TextSize) -> Option<TextEdit>>(
-    before: &str,
-    after: &str,
-    f: F,
-) {
-    let (before_cursor_pos, before) = extract_offset(before);
-    let file = SourceFile::parse(&before).ok().unwrap();
-    let result = f(&file, before_cursor_pos).expect("code action is not applicable");
-    let actual = {
-        let mut actual = before.to_string();
-        result.apply(&mut actual);
-        actual
-    };
-    let actual_cursor_pos =
-        result.apply_to_offset(before_cursor_pos).expect("cursor position is affected by the edit");
-    let actual = add_cursor(&actual, actual_cursor_pos);
-    assert_eq_text!(after, &actual);
-}
diff --git a/crates/ra_ide/src/typing.rs b/crates/ra_ide/src/typing.rs
index 6f04f0be4..39bb3b357 100644
--- a/crates/ra_ide/src/typing.rs
+++ b/crates/ra_ide/src/typing.rs
@@ -17,7 +17,7 @@ mod on_enter;
 
 use ra_db::{FilePosition, SourceDatabase};
 use ra_fmt::leading_indent;
-use ra_ide_db::{source_change::SingleFileChange, RootDatabase};
+use ra_ide_db::RootDatabase;
 use ra_syntax::{
     algo::find_node_at_offset,
     ast::{self, AstToken},
@@ -40,15 +40,11 @@ pub(crate) fn on_char_typed(
     assert!(TRIGGER_CHARS.contains(char_typed));
     let file = &db.parse(position.file_id).tree();
     assert_eq!(file.syntax().text().char_at(position.offset), Some(char_typed));
-    let single_file_change = on_char_typed_inner(file, position.offset, char_typed)?;
-    Some(single_file_change.into_source_change(position.file_id))
+    let text_edit = on_char_typed_inner(file, position.offset, char_typed)?;
+    Some(SourceChange::source_file_edit_from(position.file_id, text_edit))
 }
 
-fn on_char_typed_inner(
-    file: &SourceFile,
-    offset: TextSize,
-    char_typed: char,
-) -> Option<SingleFileChange> {
+fn on_char_typed_inner(file: &SourceFile, offset: TextSize, char_typed: char) -> Option<TextEdit> {
     assert!(TRIGGER_CHARS.contains(char_typed));
     match char_typed {
         '.' => on_dot_typed(file, offset),
@@ -61,7 +57,7 @@ fn on_char_typed_inner(
 /// Returns an edit which should be applied after `=` was typed. Primarily,
 /// this works when adding `let =`.
 // FIXME: use a snippet completion instead of this hack here.
-fn on_eq_typed(file: &SourceFile, offset: TextSize) -> Option<SingleFileChange> {
+fn on_eq_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
     assert_eq!(file.syntax().text().char_at(offset), Some('='));
     let let_stmt: ast::LetStmt = find_node_at_offset(file.syntax(), offset)?;
     if let_stmt.semicolon_token().is_some() {
@@ -79,15 +75,11 @@ fn on_eq_typed(file: &SourceFile, offset: TextSize) -> Option<SingleFileChange>
         return None;
     }
     let offset = let_stmt.syntax().text_range().end();
-    Some(SingleFileChange {
-        label: "add semicolon".to_string(),
-        edit: TextEdit::insert(offset, ";".to_string()),
-        cursor_position: None,
-    })
+    Some(TextEdit::insert(offset, ";".to_string()))
 }
 
 /// Returns an edit which should be applied when a dot ('.') is typed on a blank line, indenting the line appropriately.
-fn on_dot_typed(file: &SourceFile, offset: TextSize) -> Option<SingleFileChange> {
+fn on_dot_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
     assert_eq!(file.syntax().text().char_at(offset), Some('.'));
     let whitespace =
         file.syntax().token_at_offset(offset).left_biased().and_then(ast::Whitespace::cast)?;
@@ -108,15 +100,11 @@ fn on_dot_typed(file: &SourceFile, offset: TextSize) -> Option<SingleFileChange>
         return None;
     }
 
-    Some(SingleFileChange {
-        label: "reindent dot".to_string(),
-        edit: TextEdit::replace(TextRange::new(offset - current_indent_len, offset), target_indent),
-        cursor_position: Some(offset + target_indent_len - current_indent_len + TextSize::of('.')),
-    })
+    Some(TextEdit::replace(TextRange::new(offset - current_indent_len, offset), target_indent))
 }
 
 /// Adds a space after an arrow when `fn foo() { ... }` is turned into `fn foo() -> { ... }`
-fn on_arrow_typed(file: &SourceFile, offset: TextSize) -> Option<SingleFileChange> {
+fn on_arrow_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
     let file_text = file.syntax().text();
     assert_eq!(file_text.char_at(offset), Some('>'));
     let after_arrow = offset + TextSize::of('>');
@@ -127,11 +115,7 @@ fn on_arrow_typed(file: &SourceFile, offset: TextSize) -> Option<SingleFileChang
         return None;
     }
 
-    Some(SingleFileChange {
-        label: "add space after return type".to_string(),
-        edit: TextEdit::insert(after_arrow, " ".to_string()),
-        cursor_position: Some(after_arrow),
-    })
+    Some(TextEdit::insert(after_arrow, " ".to_string()))
 }
 
 #[cfg(test)]
@@ -140,29 +124,23 @@ mod tests {
 
     use super::*;
 
-    fn do_type_char(char_typed: char, before: &str) -> Option<(String, SingleFileChange)> {
+    fn do_type_char(char_typed: char, before: &str) -> Option<String> {
         let (offset, before) = extract_offset(before);
         let edit = TextEdit::insert(offset, char_typed.to_string());
         let mut before = before.to_string();
         edit.apply(&mut before);
         let parse = SourceFile::parse(&before);
         on_char_typed_inner(&parse.tree(), offset, char_typed).map(|it| {
-            it.edit.apply(&mut before);
-            (before.to_string(), it)
+            it.apply(&mut before);
+            before.to_string()
         })
     }
 
     fn type_char(char_typed: char, before: &str, after: &str) {
-        let (actual, file_change) = do_type_char(char_typed, before)
+        let actual = do_type_char(char_typed, before)
             .unwrap_or_else(|| panic!("typing `{}` did nothing", char_typed));
 
-        if after.contains("<|>") {
-            let (offset, after) = extract_offset(after);
-            assert_eq_text!(&after, &actual);
-            assert_eq!(file_change.cursor_position, Some(offset))
-        } else {
-            assert_eq_text!(after, &actual);
-        }
+        assert_eq_text!(after, &actual);
     }
 
     fn type_char_noop(char_typed: char, before: &str) {
@@ -350,6 +328,6 @@ fn foo() {
 
     #[test]
     fn adds_space_after_return_type() {
-        type_char('>', "fn foo() -<|>{ 92 }", "fn foo() -><|> { 92 }")
+        type_char('>', "fn foo() -<|>{ 92 }", "fn foo() -> { 92 }")
     }
 }
diff --git a/crates/ra_ide/src/typing/on_enter.rs b/crates/ra_ide/src/typing/on_enter.rs
index 78a40cc94..e7d64b4f6 100644
--- a/crates/ra_ide/src/typing/on_enter.rs
+++ b/crates/ra_ide/src/typing/on_enter.rs
@@ -38,17 +38,12 @@ pub(crate) fn on_enter(db: &RootDatabase, position: FilePosition) -> Option<Sour
     }
 
     let indent = node_indent(&file, comment.syntax())?;
-    let inserted = format!("\n{}{} ", indent, prefix);
-    let cursor_position = position.offset + TextSize::of(&inserted);
+    let inserted = format!("\n{}{} $0", indent, prefix);
     let edit = TextEdit::insert(position.offset, inserted);
 
-    Some(
-        SourceChange::source_file_edit(
-            "On enter",
-            SourceFileEdit { edit, file_id: position.file_id },
-        )
-        .with_cursor(FilePosition { offset: cursor_position, file_id: position.file_id }),
-    )
+    let mut res = SourceChange::from(SourceFileEdit { edit, file_id: position.file_id });
+    res.is_snippet = true;
+    Some(res)
 }
 
 fn followed_by_comment(comment: &ast::Comment) -> bool {
@@ -84,7 +79,7 @@ fn node_indent(file: &SourceFile, token: &SyntaxToken) -> Option<SmolStr> {
 
 #[cfg(test)]
 mod tests {
-    use test_utils::{add_cursor, assert_eq_text, extract_offset};
+    use test_utils::{assert_eq_text, extract_offset};
 
     use crate::mock_analysis::single_file;
 
@@ -98,7 +93,6 @@ mod tests {
         assert_eq!(result.source_file_edits.len(), 1);
         let mut actual = before.to_string();
         result.source_file_edits[0].edit.apply(&mut actual);
-        let actual = add_cursor(&actual, result.cursor_position.unwrap().offset);
         Some(actual)
     }
 
@@ -121,7 +115,7 @@ fn foo() {
 ",
             r"
 /// Some docs
-/// <|>
+/// $0
 fn foo() {
 }
 ",
@@ -137,7 +131,7 @@ impl S {
             r"
 impl S {
     /// Some
-    /// <|> docs.
+    /// $0 docs.
     fn foo() {}
 }
 ",
@@ -151,7 +145,7 @@ fn foo() {
 ",
             r"
 ///
-/// <|> Some docs
+/// $0 Some docs
 fn foo() {
 }
 ",
@@ -175,7 +169,7 @@ fn main() {
             r"
 fn main() {
     // Fix
-    // <|> me
+    // $0 me
     let x = 1 + 1;
 }
 ",
@@ -195,7 +189,7 @@ fn main() {
             r"
 fn main() {
     // Fix
-    // <|>
+    // $0
     // me
     let x = 1 + 1;
 }
diff --git a/crates/ra_ide_db/src/defs.rs b/crates/ra_ide_db/src/defs.rs
index 60c11178e..8b06cbfc5 100644
--- a/crates/ra_ide_db/src/defs.rs
+++ b/crates/ra_ide_db/src/defs.rs
@@ -14,7 +14,6 @@ use ra_syntax::{
     ast::{self, AstNode},
     match_ast,
 };
-use test_utils::tested_by;
 
 use crate::RootDatabase;
 
@@ -118,7 +117,6 @@ fn classify_name_inner(sema: &Semantics<RootDatabase>, name: &ast::Name) -> Opti
     match_ast! {
         match parent {
             ast::Alias(it) => {
-                tested_by!(goto_def_for_use_alias; force);
                 let use_tree = it.syntax().parent().and_then(ast::UseTree::cast)?;
                 let path = use_tree.path()?;
                 let path_segment = path.segment()?;
@@ -203,6 +201,8 @@ impl NameRefClass {
     }
 }
 
+// Note: we don't have unit-tests for this rather important function.
+// It is primarily exercised via goto definition tests in `ra_ide`.
 pub fn classify_name_ref(
     sema: &Semantics<RootDatabase>,
     name_ref: &ast::NameRef,
@@ -212,22 +212,18 @@ pub fn classify_name_ref(
     let parent = name_ref.syntax().parent()?;
 
     if let Some(method_call) = ast::MethodCallExpr::cast(parent.clone()) {
-        tested_by!(goto_def_for_methods; force);
         if let Some(func) = sema.resolve_method_call(&method_call) {
             return Some(NameRefClass::Definition(Definition::ModuleDef(func.into())));
         }
     }
 
     if let Some(field_expr) = ast::FieldExpr::cast(parent.clone()) {
-        tested_by!(goto_def_for_fields; force);
         if let Some(field) = sema.resolve_field(&field_expr) {
             return Some(NameRefClass::Definition(Definition::Field(field)));
         }
     }
 
     if let Some(record_field) = ast::RecordField::for_field_name(name_ref) {
-        tested_by!(goto_def_for_record_fields; force);
-        tested_by!(goto_def_for_field_init_shorthand; force);
         if let Some((field, local)) = sema.resolve_record_field(&record_field) {
             let field = Definition::Field(field);
             let res = match local {
@@ -239,7 +235,6 @@ pub fn classify_name_ref(
     }
 
     if let Some(record_field_pat) = ast::RecordFieldPat::cast(parent.clone()) {
-        tested_by!(goto_def_for_record_field_pats; force);
         if let Some(field) = sema.resolve_record_field_pat(&record_field_pat) {
             let field = Definition::Field(field);
             return Some(NameRefClass::Definition(field));
@@ -247,7 +242,6 @@ pub fn classify_name_ref(
     }
 
     if let Some(macro_call) = parent.ancestors().find_map(ast::MacroCall::cast) {
-        tested_by!(goto_def_for_macros; force);
         if let Some(macro_def) = sema.resolve_macro_call(&macro_call) {
             return Some(NameRefClass::Definition(Definition::Macro(macro_def)));
         }
diff --git a/crates/ra_ide_db/src/lib.rs b/crates/ra_ide_db/src/lib.rs
index 52fcd7b6f..1b74e6558 100644
--- a/crates/ra_ide_db/src/lib.rs
+++ b/crates/ra_ide_db/src/lib.rs
@@ -2,9 +2,7 @@
 //!
 //! It is mainly a `HirDatabase` for semantic analysis, plus a `SymbolsDatabase`, for fuzzy search.
 
-pub mod marks;
 pub mod line_index;
-pub mod line_index_utils;
 pub mod symbol_index;
 pub mod change;
 pub mod defs;
diff --git a/crates/ra_ide_db/src/line_index_utils.rs b/crates/ra_ide_db/src/line_index_utils.rs
deleted file mode 100644
index 7fa6fc448..000000000
--- a/crates/ra_ide_db/src/line_index_utils.rs
+++ /dev/null
@@ -1,302 +0,0 @@
-//! Code actions can specify desirable final position of the cursor.
-//!
-//! The position is specified as a `TextSize` in the final file. We need to send
-//! it in `(Line, Column)` coordinate though. However, we only have a LineIndex
-//! for a file pre-edit!
-//!
-//! Code in this module applies this "to (Line, Column) after edit"
-//! transformation.
-
-use std::convert::TryInto;
-
-use ra_syntax::{TextRange, TextSize};
-use ra_text_edit::{Indel, TextEdit};
-
-use crate::line_index::{LineCol, LineIndex, Utf16Char};
-
-pub fn translate_offset_with_edit(
-    line_index: &LineIndex,
-    offset: TextSize,
-    text_edit: &TextEdit,
-) -> LineCol {
-    let mut state = Edits::from_text_edit(&text_edit);
-
-    let mut res = RunningLineCol::new();
-
-    macro_rules! test_step {
-        ($x:ident) => {
-            match &$x {
-                Step::Newline(n) => {
-                    if offset < *n {
-                        return res.to_line_col(offset);
-                    } else {
-                        res.add_line(*n);
-                    }
-                }
-                Step::Utf16Char(x) => {
-                    if offset < x.end() {
-                        // if the offset is inside a multibyte char it's invalid
-                        // clamp it to the start of the char
-                        let clamp = offset.min(x.start());
-                        return res.to_line_col(clamp);
-                    } else {
-                        res.adjust_col(*x);
-                    }
-                }
-            }
-        };
-    }
-
-    for orig_step in LineIndexStepIter::from(line_index) {
-        loop {
-            let translated_step = state.translate_step(&orig_step);
-            match state.next_steps(&translated_step) {
-                NextSteps::Use => {
-                    test_step!(translated_step);
-                    break;
-                }
-                NextSteps::ReplaceMany(ns) => {
-                    for n in ns {
-                        test_step!(n);
-                    }
-                    break;
-                }
-                NextSteps::AddMany(ns) => {
-                    for n in ns {
-                        test_step!(n);
-                    }
-                }
-            }
-        }
-    }
-
-    loop {
-        match state.next_inserted_steps() {
-            None => break,
-            Some(ns) => {
-                for n in ns {
-                    test_step!(n);
-                }
-            }
-        }
-    }
-
-    res.to_line_col(offset)
-}
-
-#[derive(Debug, Clone)]
-enum Step {
-    Newline(TextSize),
-    Utf16Char(TextRange),
-}
-
-#[derive(Debug)]
-struct LineIndexStepIter<'a> {
-    line_index: &'a LineIndex,
-    next_newline_idx: usize,
-    utf16_chars: Option<(TextSize, std::slice::Iter<'a, Utf16Char>)>,
-}
-
-impl LineIndexStepIter<'_> {
-    fn from(line_index: &LineIndex) -> LineIndexStepIter {
-        let mut x = LineIndexStepIter { line_index, next_newline_idx: 0, utf16_chars: None };
-        // skip first newline since it's not real
-        x.next();
-        x
-    }
-}
-
-impl Iterator for LineIndexStepIter<'_> {
-    type Item = Step;
-    fn next(&mut self) -> Option<Step> {
-        self.utf16_chars
-            .as_mut()
-            .and_then(|(newline, x)| {
-                let x = x.next()?;
-                Some(Step::Utf16Char(TextRange::new(*newline + x.start, *newline + x.end)))
-            })
-            .or_else(|| {
-                let next_newline = *self.line_index.newlines.get(self.next_newline_idx)?;
-                self.utf16_chars = self
-                    .line_index
-                    .utf16_lines
-                    .get(&(self.next_newline_idx as u32))
-                    .map(|x| (next_newline, x.iter()));
-                self.next_newline_idx += 1;
-                Some(Step::Newline(next_newline))
-            })
-    }
-}
-
-#[derive(Debug)]
-struct OffsetStepIter<'a> {
-    text: &'a str,
-    offset: TextSize,
-}
-
-impl Iterator for OffsetStepIter<'_> {
-    type Item = Step;
-    fn next(&mut self) -> Option<Step> {
-        let (next, next_offset) = self
-            .text
-            .char_indices()
-            .filter_map(|(i, c)| {
-                let i: TextSize = i.try_into().unwrap();
-                let char_len = TextSize::of(c);
-                if c == '\n' {
-                    let next_offset = self.offset + i + char_len;
-                    let next = Step::Newline(next_offset);
-                    Some((next, next_offset))
-                } else {
-                    if !c.is_ascii() {
-                        let start = self.offset + i;
-                        let end = start + char_len;
-                        let next = Step::Utf16Char(TextRange::new(start, end));
-                        let next_offset = end;
-                        Some((next, next_offset))
-                    } else {
-                        None
-                    }
-                }
-            })
-            .next()?;
-        let next_idx: usize = (next_offset - self.offset).into();
-        self.text = &self.text[next_idx..];
-        self.offset = next_offset;
-        Some(next)
-    }
-}
-
-#[derive(Debug)]
-enum NextSteps<'a> {
-    Use,
-    ReplaceMany(OffsetStepIter<'a>),
-    AddMany(OffsetStepIter<'a>),
-}
-
-#[derive(Debug)]
-struct TranslatedEdit<'a> {
-    delete: TextRange,
-    insert: &'a str,
-    diff: i64,
-}
-
-struct Edits<'a> {
-    edits: &'a [Indel],
-    current: Option<TranslatedEdit<'a>>,
-    acc_diff: i64,
-}
-
-impl<'a> Edits<'a> {
-    fn from_text_edit(text_edit: &'a TextEdit) -> Edits<'a> {
-        let mut x = Edits { edits: text_edit.as_indels(), current: None, acc_diff: 0 };
-        x.advance_edit();
-        x
-    }
-    fn advance_edit(&mut self) {
-        self.acc_diff += self.current.as_ref().map_or(0, |x| x.diff);
-        match self.edits.split_first() {
-            Some((next, rest)) => {
-                let delete = self.translate_range(next.delete);
-                let diff = next.insert.len() as i64 - usize::from(next.delete.len()) as i64;
-                self.current = Some(TranslatedEdit { delete, insert: &next.insert, diff });
-                self.edits = rest;
-            }
-            None => {
-                self.current = None;
-            }
-        }
-    }
-
-    fn next_inserted_steps(&mut self) -> Option<OffsetStepIter<'a>> {
-        let cur = self.current.as_ref()?;
-        let res = Some(OffsetStepIter { offset: cur.delete.start(), text: &cur.insert });
-        self.advance_edit();
-        res
-    }
-
-    fn next_steps(&mut self, step: &Step) -> NextSteps {
-        let step_pos = match *step {
-            Step::Newline(n) => n,
-            Step::Utf16Char(r) => r.end(),
-        };
-        match &mut self.current {
-            Some(edit) => {
-                if step_pos <= edit.delete.start() {
-                    NextSteps::Use
-                } else if step_pos <= edit.delete.end() {
-                    let iter = OffsetStepIter { offset: edit.delete.start(), text: &edit.insert };
-                    // empty slice to avoid returning steps again
-                    edit.insert = &edit.insert[edit.insert.len()..];
-                    NextSteps::ReplaceMany(iter)
-                } else {
-                    let iter = OffsetStepIter { offset: edit.delete.start(), text: &edit.insert };
-                    // empty slice to avoid returning steps again
-                    edit.insert = &edit.insert[edit.insert.len()..];
-                    self.advance_edit();
-                    NextSteps::AddMany(iter)
-                }
-            }
-            None => NextSteps::Use,
-        }
-    }
-
-    fn translate_range(&self, range: TextRange) -> TextRange {
-        if self.acc_diff == 0 {
-            range
-        } else {
-            let start = self.translate(range.start());
-            let end = self.translate(range.end());
-            TextRange::new(start, end)
-        }
-    }
-
-    fn translate(&self, x: TextSize) -> TextSize {
-        if self.acc_diff == 0 {
-            x
-        } else {
-            TextSize::from((usize::from(x) as i64 + self.acc_diff) as u32)
-        }
-    }
-
-    fn translate_step(&self, x: &Step) -> Step {
-        if self.acc_diff == 0 {
-            x.clone()
-        } else {
-            match *x {
-                Step::Newline(n) => Step::Newline(self.translate(n)),
-                Step::Utf16Char(r) => Step::Utf16Char(self.translate_range(r)),
-            }
-        }
-    }
-}
-
-#[derive(Debug)]
-struct RunningLineCol {
-    line: u32,
-    last_newline: TextSize,
-    col_adjust: TextSize,
-}
-
-impl RunningLineCol {
-    fn new() -> RunningLineCol {
-        RunningLineCol { line: 0, last_newline: TextSize::from(0), col_adjust: TextSize::from(0) }
-    }
-
-    fn to_line_col(&self, offset: TextSize) -> LineCol {
-        LineCol {
-            line: self.line,
-            col_utf16: ((offset - self.last_newline) - self.col_adjust).into(),
-        }
-    }
-
-    fn add_line(&mut self, newline: TextSize) {
-        self.line += 1;
-        self.last_newline = newline;
-        self.col_adjust = TextSize::from(0);
-    }
-
-    fn adjust_col(&mut self, range: TextRange) {
-        self.col_adjust += range.len() - TextSize::from(1);
-    }
-}
diff --git a/crates/ra_ide_db/src/marks.rs b/crates/ra_ide_db/src/marks.rs
deleted file mode 100644
index 386fe605c..000000000
--- a/crates/ra_ide_db/src/marks.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-//! See test_utils/src/marks.rs
-
-test_utils::marks![
-    goto_def_for_macros
-    goto_def_for_use_alias
-    goto_def_for_methods
-    goto_def_for_fields
-    goto_def_for_record_fields
-    goto_def_for_field_init_shorthand
-    goto_def_for_record_field_pats
-    search_filters_by_range
-];
diff --git a/crates/ra_ide_db/src/search.rs b/crates/ra_ide_db/src/search.rs
index b464959fc..589f44771 100644
--- a/crates/ra_ide_db/src/search.rs
+++ b/crates/ra_ide_db/src/search.rs
@@ -12,7 +12,6 @@ use ra_db::{FileId, FileRange, SourceDatabaseExt};
 use ra_prof::profile;
 use ra_syntax::{ast, match_ast, AstNode, TextRange, TextSize};
 use rustc_hash::FxHashMap;
-use test_utils::tested_by;
 
 use crate::{
     defs::{classify_name_ref, Definition, NameRefClass},
@@ -209,7 +208,6 @@ impl Definition {
             for (idx, _) in text.match_indices(pat) {
                 let offset: TextSize = idx.try_into().unwrap();
                 if !search_range.contains_inclusive(offset) {
-                    tested_by!(search_filters_by_range; force);
                     continue;
                 }
 
diff --git a/crates/ra_ide_db/src/source_change.rs b/crates/ra_ide_db/src/source_change.rs
index af81a91a4..e713f4b7e 100644
--- a/crates/ra_ide_db/src/source_change.rs
+++ b/crates/ra_ide_db/src/source_change.rs
@@ -3,90 +3,35 @@
 //!
 //! It can be viewed as a dual for `AnalysisChange`.
 
-use ra_db::{FileId, FilePosition, RelativePathBuf, SourceRootId};
-use ra_text_edit::{TextEdit, TextSize};
+use ra_db::{FileId, RelativePathBuf, SourceRootId};
+use ra_text_edit::TextEdit;
 
 #[derive(Debug, Clone)]
 pub struct SourceChange {
-    /// For display in the undo log in the editor
-    pub label: String,
     pub source_file_edits: Vec<SourceFileEdit>,
     pub file_system_edits: Vec<FileSystemEdit>,
-    pub cursor_position: Option<FilePosition>,
+    pub is_snippet: bool,
 }
 
 impl SourceChange {
     /// Creates a new SourceChange with the given label
     /// from the edits.
-    pub fn from_edits<L: Into<String>>(
-        label: L,
+    pub fn from_edits(
         source_file_edits: Vec<SourceFileEdit>,
         file_system_edits: Vec<FileSystemEdit>,
     ) -> Self {
-        SourceChange {
-            label: label.into(),
-            source_file_edits,
-            file_system_edits,
-            cursor_position: None,
-        }
+        SourceChange { source_file_edits, file_system_edits, is_snippet: false }
     }
 
     /// Creates a new SourceChange with the given label,
     /// containing only the given `SourceFileEdits`.
-    pub fn source_file_edits<L: Into<String>>(label: L, edits: Vec<SourceFileEdit>) -> Self {
-        let label = label.into();
-        assert!(label.starts_with(char::is_uppercase));
-        SourceChange {
-            label: label,
-            source_file_edits: edits,
-            file_system_edits: vec![],
-            cursor_position: None,
-        }
-    }
-
-    /// Creates a new SourceChange with the given label,
-    /// containing only the given `FileSystemEdits`.
-    pub(crate) fn file_system_edits<L: Into<String>>(label: L, edits: Vec<FileSystemEdit>) -> Self {
-        SourceChange {
-            label: label.into(),
-            source_file_edits: vec![],
-            file_system_edits: edits,
-            cursor_position: None,
-        }
-    }
-
-    /// Creates a new SourceChange with the given label,
-    /// containing only a single `SourceFileEdit`.
-    pub fn source_file_edit<L: Into<String>>(label: L, edit: SourceFileEdit) -> Self {
-        SourceChange::source_file_edits(label, vec![edit])
-    }
-
-    /// Creates a new SourceChange with the given label
-    /// from the given `FileId` and `TextEdit`
-    pub fn source_file_edit_from<L: Into<String>>(
-        label: L,
-        file_id: FileId,
-        edit: TextEdit,
-    ) -> Self {
-        SourceChange::source_file_edit(label, SourceFileEdit { file_id, edit })
+    pub fn source_file_edits(edits: Vec<SourceFileEdit>) -> Self {
+        SourceChange { source_file_edits: edits, file_system_edits: vec![], is_snippet: false }
     }
-
     /// Creates a new SourceChange with the given label
     /// from the given `FileId` and `TextEdit`
-    pub fn file_system_edit<L: Into<String>>(label: L, edit: FileSystemEdit) -> Self {
-        SourceChange::file_system_edits(label, vec![edit])
-    }
-
-    /// Sets the cursor position to the given `FilePosition`
-    pub fn with_cursor(mut self, cursor_position: FilePosition) -> Self {
-        self.cursor_position = Some(cursor_position);
-        self
-    }
-
-    /// Sets the cursor position to the given `FilePosition`
-    pub fn with_cursor_opt(mut self, cursor_position: Option<FilePosition>) -> Self {
-        self.cursor_position = cursor_position;
-        self
+    pub fn source_file_edit_from(file_id: FileId, edit: TextEdit) -> Self {
+        SourceFileEdit { file_id, edit }.into()
     }
 }
 
@@ -96,25 +41,28 @@ pub struct SourceFileEdit {
     pub edit: TextEdit,
 }
 
+impl From<SourceFileEdit> for SourceChange {
+    fn from(edit: SourceFileEdit) -> SourceChange {
+        SourceChange {
+            source_file_edits: vec![edit],
+            file_system_edits: Vec::new(),
+            is_snippet: false,
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum FileSystemEdit {
     CreateFile { source_root: SourceRootId, path: RelativePathBuf },
     MoveFile { src: FileId, dst_source_root: SourceRootId, dst_path: RelativePathBuf },
 }
 
-pub struct SingleFileChange {
-    pub label: String,
-    pub edit: TextEdit,
-    pub cursor_position: Option<TextSize>,
-}
-
-impl SingleFileChange {
-    pub fn into_source_change(self, file_id: FileId) -> SourceChange {
+impl From<FileSystemEdit> for SourceChange {
+    fn from(edit: FileSystemEdit) -> SourceChange {
         SourceChange {
-            label: self.label,
-            source_file_edits: vec![SourceFileEdit { file_id, edit: self.edit }],
-            file_system_edits: Vec::new(),
-            cursor_position: self.cursor_position.map(|offset| FilePosition { file_id, offset }),
+            source_file_edits: Vec::new(),
+            file_system_edits: vec![edit],
+            is_snippet: false,
         }
     }
 }
diff --git a/crates/ra_syntax/Cargo.toml b/crates/ra_syntax/Cargo.toml
index c07ff488e..a9a5cc7bc 100644
--- a/crates/ra_syntax/Cargo.toml
+++ b/crates/ra_syntax/Cargo.toml
@@ -13,7 +13,7 @@ doctest = false
 [dependencies]
 itertools = "0.9.0"
 rowan = "0.10.0"
-rustc_lexer = { version = "656.0.0", package = "rustc-ap-rustc_lexer" }
+rustc_lexer = { version = "660.0.0", package = "rustc-ap-rustc_lexer" }
 rustc-hash = "1.1.0"
 arrayvec = "0.5.1"
 once_cell = "1.3.1"
diff --git a/crates/ra_syntax/src/algo.rs b/crates/ra_syntax/src/algo.rs
index 2a8dac757..664894d1f 100644
--- a/crates/ra_syntax/src/algo.rs
+++ b/crates/ra_syntax/src/algo.rs
@@ -266,6 +266,15 @@ impl<'a> SyntaxRewriter<'a> {
         let replacement = Replacement::Single(with.clone().into());
         self.replacements.insert(what, replacement);
     }
+    pub fn replace_with_many<T: Clone + Into<SyntaxElement>>(
+        &mut self,
+        what: &T,
+        with: Vec<SyntaxElement>,
+    ) {
+        let what = what.clone().into();
+        let replacement = Replacement::Many(with);
+        self.replacements.insert(what, replacement);
+    }
     pub fn replace_ast<T: AstNode>(&mut self, what: &T, with: &T) {
         self.replace(what.syntax(), with.syntax())
     }
@@ -302,31 +311,41 @@ impl<'a> SyntaxRewriter<'a> {
 
     fn rewrite_children(&self, node: &SyntaxNode) -> SyntaxNode {
         //  FIXME: this could be made much faster.
-        let new_children =
-            node.children_with_tokens().flat_map(|it| self.rewrite_self(&it)).collect::<Vec<_>>();
+        let mut new_children = Vec::new();
+        for child in node.children_with_tokens() {
+            self.rewrite_self(&mut new_children, &child);
+        }
         with_children(node, new_children)
     }
 
     fn rewrite_self(
         &self,
+        acc: &mut Vec<NodeOrToken<rowan::GreenNode, rowan::GreenToken>>,
         element: &SyntaxElement,
-    ) -> Option<NodeOrToken<rowan::GreenNode, rowan::GreenToken>> {
+    ) {
         if let Some(replacement) = self.replacement(&element) {
-            return match replacement {
+            match replacement {
                 Replacement::Single(NodeOrToken::Node(it)) => {
-                    Some(NodeOrToken::Node(it.green().clone()))
+                    acc.push(NodeOrToken::Node(it.green().clone()))
                 }
                 Replacement::Single(NodeOrToken::Token(it)) => {
-                    Some(NodeOrToken::Token(it.green().clone()))
+                    acc.push(NodeOrToken::Token(it.green().clone()))
                 }
-                Replacement::Delete => None,
+                Replacement::Many(replacements) => {
+                    acc.extend(replacements.iter().map(|it| match it {
+                        NodeOrToken::Node(it) => NodeOrToken::Node(it.green().clone()),
+                        NodeOrToken::Token(it) => NodeOrToken::Token(it.green().clone()),
+                    }))
+                }
+                Replacement::Delete => (),
             };
+            return;
         }
         let res = match element {
             NodeOrToken::Token(it) => NodeOrToken::Token(it.green().clone()),
             NodeOrToken::Node(it) => NodeOrToken::Node(self.rewrite_children(it).green().clone()),
         };
-        Some(res)
+        acc.push(res)
     }
 }
 
@@ -341,6 +360,7 @@ impl ops::AddAssign for SyntaxRewriter<'_> {
 enum Replacement {
     Delete,
     Single(SyntaxElement),
+    Many(Vec<SyntaxElement>),
 }
 
 fn with_children(
diff --git a/crates/ra_syntax/src/ast/edit.rs b/crates/ra_syntax/src/ast/edit.rs
index 24a1e1d91..29eb3fcb9 100644
--- a/crates/ra_syntax/src/ast/edit.rs
+++ b/crates/ra_syntax/src/ast/edit.rs
@@ -1,7 +1,10 @@
 //! This module contains functions for editing syntax trees. As the trees are
 //! immutable, all function here return a fresh copy of the tree, instead of
 //! doing an in-place modification.
-use std::{iter, ops::RangeInclusive};
+use std::{
+    fmt, iter,
+    ops::{self, RangeInclusive},
+};
 
 use arrayvec::ArrayVec;
 
@@ -437,6 +440,28 @@ impl From<u8> for IndentLevel {
     }
 }
 
+impl fmt::Display for IndentLevel {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let spaces = "                                        ";
+        let buf;
+        let len = self.0 as usize * 4;
+        let indent = if len <= spaces.len() {
+            &spaces[..len]
+        } else {
+            buf = iter::repeat(' ').take(len).collect::<String>();
+            &buf
+        };
+        fmt::Display::fmt(indent, f)
+    }
+}
+
+impl ops::Add<u8> for IndentLevel {
+    type Output = IndentLevel;
+    fn add(self, rhs: u8) -> IndentLevel {
+        IndentLevel(self.0 + rhs)
+    }
+}
+
 impl IndentLevel {
     pub fn from_node(node: &SyntaxNode) -> IndentLevel {
         let first_token = match node.first_token() {
@@ -453,6 +478,14 @@ impl IndentLevel {
         IndentLevel(0)
     }
 
+    /// XXX: this intentionally doesn't change the indent of the very first token.
+    /// Ie, in something like
+    /// ```
+    /// fn foo() {
+    ///    92
+    /// }
+    /// ```
+    /// if you indent the block, the `{` token would stay put.
     fn increase_indent(self, node: SyntaxNode) -> SyntaxNode {
         let mut rewriter = SyntaxRewriter::default();
         node.descendants_with_tokens()
@@ -463,12 +496,7 @@ impl IndentLevel {
                 text.contains('\n')
             })
             .for_each(|ws| {
-                let new_ws = make::tokens::whitespace(&format!(
-                    "{}{:width$}",
-                    ws.syntax().text(),
-                    "",
-                    width = self.0 as usize * 4
-                ));
+                let new_ws = make::tokens::whitespace(&format!("{}{}", ws.syntax(), self,));
                 rewriter.replace(ws.syntax(), &new_ws)
             });
         rewriter.rewrite(&node)
@@ -485,7 +513,7 @@ impl IndentLevel {
             })
             .for_each(|ws| {
                 let new_ws = make::tokens::whitespace(
-                    &ws.syntax().text().replace(&format!("\n{:1$}", "", self.0 as usize * 4), "\n"),
+                    &ws.syntax().text().replace(&format!("\n{}", self), "\n"),
                 );
                 rewriter.replace(ws.syntax(), &new_ws)
             });
diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index d0e960fb4..da0eb0926 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -1,5 +1,9 @@
 //! This module contains free-standing functions for creating AST fragments out
 //! of smaller pieces.
+//!
+//! Note that all functions here intended to be stupid constructors, which just
+//! assemble a finish node from immediate children. If you want to do something
+//! smarter than that, it probably doesn't belong in this module.
 use itertools::Itertools;
 use stdx::format_to;
 
@@ -95,6 +99,9 @@ pub fn expr_empty_block() -> ast::Expr {
 pub fn expr_unimplemented() -> ast::Expr {
     expr_from_text("unimplemented!()")
 }
+pub fn expr_unreachable() -> ast::Expr {
+    expr_from_text("unreachable!()")
+}
 pub fn expr_todo() -> ast::Expr {
     expr_from_text("todo!()")
 }
@@ -264,10 +271,6 @@ pub fn token(kind: SyntaxKind) -> SyntaxToken {
         .unwrap_or_else(|| panic!("unhandled token: {:?}", kind))
 }
 
-pub fn unreachable_macro_call() -> ast::MacroCall {
-    ast_from_text(&format!("unreachable!()"))
-}
-
 pub fn param(name: String, ty: String) -> ast::Param {
     ast_from_text(&format!("fn f({}: {}) {{ }}", name, ty))
 }
@@ -277,7 +280,12 @@ pub fn param_list(pats: impl IntoIterator<Item = ast::Param>) -> ast::ParamList
     ast_from_text(&format!("fn f({}) {{ }}", args))
 }
 
+pub fn visibility_pub_crate() -> ast::Visibility {
+    ast_from_text("pub(crate) struct S")
+}
+
 pub fn fn_def(
+    visibility: Option<ast::Visibility>,
     fn_name: ast::Name,
     type_params: Option<ast::TypeParamList>,
     params: ast::ParamList,
@@ -285,21 +293,11 @@ pub fn fn_def(
 ) -> ast::FnDef {
     let type_params =
         if let Some(type_params) = type_params { format!("<{}>", type_params) } else { "".into() };
-    ast_from_text(&format!("fn {}{}{} {}", fn_name, type_params, params, body))
-}
-
-pub fn add_leading_newlines(amount_of_newlines: usize, t: impl AstNode) -> ast::SourceFile {
-    let newlines = "\n".repeat(amount_of_newlines);
-    ast_from_text(&format!("{}{}", newlines, t.syntax()))
-}
-
-pub fn add_trailing_newlines(amount_of_newlines: usize, t: impl AstNode) -> ast::SourceFile {
-    let newlines = "\n".repeat(amount_of_newlines);
-    ast_from_text(&format!("{}{}", t.syntax(), newlines))
-}
-
-pub fn add_pub_crate_modifier(fn_def: ast::FnDef) -> ast::FnDef {
-    ast_from_text(&format!("pub(crate) {}", fn_def))
+    let visibility = match visibility {
+        None => String::new(),
+        Some(it) => format!("{} ", it),
+    };
+    ast_from_text(&format!("{}fn {}{}{} {}", visibility, fn_name, type_params, params, body))
 }
 
 fn ast_from_text<N: AstNode>(text: &str) -> N {
diff --git a/crates/ra_syntax/src/ast/tokens.rs b/crates/ra_syntax/src/ast/tokens.rs
index 74906d8a6..3cd6d99c3 100644
--- a/crates/ra_syntax/src/ast/tokens.rs
+++ b/crates/ra_syntax/src/ast/tokens.rs
@@ -6,6 +6,7 @@ use crate::{
     ast::{AstToken, Comment, RawString, String, Whitespace},
     TextRange, TextSize,
 };
+use rustc_lexer::unescape::{unescape_literal, Mode};
 
 impl Comment {
     pub fn kind(&self) -> CommentKind {
@@ -147,7 +148,7 @@ impl HasStringValue for String {
 
         let mut buf = std::string::String::with_capacity(text.len());
         let mut has_error = false;
-        rustc_lexer::unescape::unescape_str(text, &mut |_, unescaped_char| match unescaped_char {
+        unescape_literal(text, Mode::Str, &mut |_, unescaped_char| match unescaped_char {
             Ok(c) => buf.push(c),
             Err(_) => has_error = true,
         });
@@ -498,7 +499,7 @@ impl HasFormatSpecifier for String {
         let offset = self.text_range_between_quotes()?.start() - self.syntax().text_range().start();
 
         let mut res = Vec::with_capacity(text.len());
-        rustc_lexer::unescape::unescape_str(text, &mut |range, unescaped_char| {
+        unescape_literal(text, Mode::Str, &mut |range, unescaped_char| {
             res.push((
                 TextRange::new(range.start.try_into().unwrap(), range.end.try_into().unwrap())
                     + offset,
diff --git a/crates/ra_syntax/src/validation.rs b/crates/ra_syntax/src/validation.rs
index d68cf0a82..fdec48fb0 100644
--- a/crates/ra_syntax/src/validation.rs
+++ b/crates/ra_syntax/src/validation.rs
@@ -2,15 +2,15 @@
 
 mod block;
 
-use std::convert::TryFrom;
-
-use rustc_lexer::unescape;
-
 use crate::{
     ast, match_ast, AstNode, SyntaxError,
     SyntaxKind::{BYTE, BYTE_STRING, CHAR, CONST_DEF, FN_DEF, INT_NUMBER, STRING, TYPE_ALIAS_DEF},
     SyntaxNode, SyntaxToken, TextSize, T,
 };
+use rustc_lexer::unescape::{
+    self, unescape_byte, unescape_byte_literal, unescape_char, unescape_literal, Mode,
+};
+use std::convert::TryFrom;
 
 fn rustc_unescape_error_to_string(err: unescape::EscapeError) -> &'static str {
     use unescape::EscapeError as EE;
@@ -81,10 +81,8 @@ fn rustc_unescape_error_to_string(err: unescape::EscapeError) -> &'static str {
 
 pub(crate) fn validate(root: &SyntaxNode) -> Vec<SyntaxError> {
     // FIXME:
-    // * Add validation of character literal containing only a single char
-    // * Add validation of `crate` keyword not appearing in the middle of the symbol path
+    // * Add unescape validation of raw string literals and raw byte string literals
     // * Add validation of doc comments are being attached to nodes
-    // * Remove validation of unterminated literals (it is already implemented in `tokenize()`)
 
     let mut errors = Vec::new();
     for node in root.descendants() {
@@ -121,18 +119,18 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
 
     match token.kind() {
         BYTE => {
-            if let Some(Err(e)) = unquote(text, 2, '\'').map(unescape::unescape_byte) {
+            if let Some(Err(e)) = unquote(text, 2, '\'').map(unescape_byte) {
                 push_err(2, e);
             }
         }
         CHAR => {
-            if let Some(Err(e)) = unquote(text, 1, '\'').map(unescape::unescape_char) {
+            if let Some(Err(e)) = unquote(text, 1, '\'').map(unescape_char) {
                 push_err(1, e);
             }
         }
         BYTE_STRING => {
             if let Some(without_quotes) = unquote(text, 2, '"') {
-                unescape::unescape_byte_str(without_quotes, &mut |range, char| {
+                unescape_byte_literal(without_quotes, Mode::ByteStr, &mut |range, char| {
                     if let Err(err) = char {
                         push_err(2, (range.start, err));
                     }
@@ -141,7 +139,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
         }
         STRING => {
             if let Some(without_quotes) = unquote(text, 1, '"') {
-                unescape::unescape_str(without_quotes, &mut |range, char| {
+                unescape_literal(without_quotes, Mode::Str, &mut |range, char| {
                     if let Err(err) = char {
                         push_err(1, (range.start, err));
                     }
diff --git a/crates/ra_text_edit/src/lib.rs b/crates/ra_text_edit/src/lib.rs
index c4f945101..25554f583 100644
--- a/crates/ra_text_edit/src/lib.rs
+++ b/crates/ra_text_edit/src/lib.rs
@@ -3,6 +3,7 @@
 //! `rust-analyzer` never mutates text itself and only sends diffs to clients,
 //! so `TextEdit` is the ultimate representation of the work done by
 //! rust-analyzer.
+use std::{slice, vec};
 
 pub use text_size::{TextRange, TextSize};
 
@@ -16,7 +17,7 @@ pub struct Indel {
     pub delete: TextRange,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Default, Debug, Clone)]
 pub struct TextEdit {
     indels: Vec<Indel>,
 }
@@ -63,25 +64,24 @@ impl TextEdit {
         builder.finish()
     }
 
-    pub(crate) fn from_indels(mut indels: Vec<Indel>) -> TextEdit {
-        indels.sort_by_key(|a| (a.delete.start(), a.delete.end()));
-        for (a1, a2) in indels.iter().zip(indels.iter().skip(1)) {
-            assert!(a1.delete.end() <= a2.delete.start())
-        }
-        TextEdit { indels }
+    pub fn len(&self) -> usize {
+        self.indels.len()
     }
 
     pub fn is_empty(&self) -> bool {
         self.indels.is_empty()
     }
 
-    // FXME: impl IntoIter instead
-    pub fn as_indels(&self) -> &[Indel] {
-        &self.indels
+    pub fn iter(&self) -> slice::Iter<'_, Indel> {
+        self.indels.iter()
+    }
+
+    pub fn into_iter(self) -> vec::IntoIter<Indel> {
+        self.indels.into_iter()
     }
 
     pub fn apply(&self, text: &mut String) {
-        match self.indels.len() {
+        match self.len() {
             0 => return,
             1 => {
                 self.indels[0].apply(text);
@@ -114,6 +114,17 @@ impl TextEdit {
         *text = buf
     }
 
+    pub fn union(&mut self, other: TextEdit) -> Result<(), TextEdit> {
+        // FIXME: can be done without allocating intermediate vector
+        let mut all = self.iter().chain(other.iter()).collect::<Vec<_>>();
+        if !check_disjoint(&mut all) {
+            return Err(other);
+        }
+        self.indels.extend(other.indels);
+        assert!(check_disjoint(&mut self.indels));
+        Ok(())
+    }
+
     pub fn apply_to_offset(&self, offset: TextSize) -> Option<TextSize> {
         let mut res = offset;
         for indel in self.indels.iter() {
@@ -141,9 +152,19 @@ impl TextEditBuilder {
         self.indels.push(Indel::insert(offset, text))
     }
     pub fn finish(self) -> TextEdit {
-        TextEdit::from_indels(self.indels)
+        let mut indels = self.indels;
+        assert!(check_disjoint(&mut indels));
+        TextEdit { indels }
     }
     pub fn invalidates_offset(&self, offset: TextSize) -> bool {
         self.indels.iter().any(|indel| indel.delete.contains_inclusive(offset))
     }
 }
+
+fn check_disjoint(indels: &mut [impl std::borrow::Borrow<Indel>]) -> bool {
+    indels.sort_by_key(|indel| (indel.borrow().delete.start(), indel.borrow().delete.end()));
+    indels
+        .iter()
+        .zip(indels.iter().skip(1))
+        .all(|(l, r)| l.borrow().delete.end() <= r.borrow().delete.start())
+}
diff --git a/crates/rust-analyzer/src/bin/main.rs b/crates/rust-analyzer/src/bin/main.rs
index 09908458d..e82fd57de 100644
--- a/crates/rust-analyzer/src/bin/main.rs
+++ b/crates/rust-analyzer/src/bin/main.rs
@@ -74,12 +74,25 @@ fn run_server() -> Result<()> {
     log::info!("lifecycle: server started");
 
     let (connection, io_threads) = Connection::stdio();
-    let server_capabilities = serde_json::to_value(rust_analyzer::server_capabilities()).unwrap();
 
-    let initialize_params = connection.initialize(server_capabilities)?;
+    let (initialize_id, initialize_params) = connection.initialize_start()?;
     let initialize_params =
         from_json::<lsp_types::InitializeParams>("InitializeParams", initialize_params)?;
 
+    let server_capabilities = rust_analyzer::server_capabilities(&initialize_params.capabilities);
+
+    let initialize_result = lsp_types::InitializeResult {
+        capabilities: server_capabilities,
+        server_info: Some(lsp_types::ServerInfo {
+            name: String::from("rust-analyzer"),
+            version: Some(String::from(env!("REV"))),
+        }),
+    };
+
+    let initialize_result = serde_json::to_value(initialize_result).unwrap();
+
+    connection.initialize_finish(initialize_id, initialize_result)?;
+
     if let Some(client_info) = initialize_params.client_info {
         log::info!("Client '{}' {}", client_info.name, client_info.version.unwrap_or_default());
     }
diff --git a/crates/rust-analyzer/src/caps.rs b/crates/rust-analyzer/src/caps.rs
index 110c9a442..780fc9317 100644
--- a/crates/rust-analyzer/src/caps.rs
+++ b/crates/rust-analyzer/src/caps.rs
@@ -1,19 +1,23 @@
 //! Advertizes the capabilities of the LSP Server.
 use std::env;
 
-use crate::semantic_tokens;
-
 use lsp_types::{
-    CallHierarchyServerCapability, CodeActionOptions, CodeActionProviderCapability,
-    CodeLensOptions, CompletionOptions, DocumentOnTypeFormattingOptions,
-    FoldingRangeProviderCapability, ImplementationProviderCapability, RenameOptions,
-    RenameProviderCapability, SaveOptions, SelectionRangeProviderCapability,
-    SemanticTokensDocumentProvider, SemanticTokensLegend, SemanticTokensOptions,
-    ServerCapabilities, SignatureHelpOptions, TextDocumentSyncCapability, TextDocumentSyncKind,
-    TextDocumentSyncOptions, TypeDefinitionProviderCapability, WorkDoneProgressOptions,
+    CallHierarchyServerCapability, ClientCapabilities, CodeActionOptions,
+    CodeActionProviderCapability, CodeLensOptions, CompletionOptions,
+    DocumentOnTypeFormattingOptions, FoldingRangeProviderCapability,
+    ImplementationProviderCapability, RenameOptions, RenameProviderCapability, SaveOptions,
+    SelectionRangeProviderCapability, SemanticTokensDocumentProvider, SemanticTokensLegend,
+    SemanticTokensOptions, ServerCapabilities, SignatureHelpOptions, TextDocumentSyncCapability,
+    TextDocumentSyncKind, TextDocumentSyncOptions, TypeDefinitionProviderCapability,
+    WorkDoneProgressOptions,
 };
+use serde_json::json;
+
+use crate::semantic_tokens;
+
+pub fn server_capabilities(client_caps: &ClientCapabilities) -> ServerCapabilities {
+    let code_action_provider = code_action_capabilities(client_caps);
 
-pub fn server_capabilities() -> ServerCapabilities {
     ServerCapabilities {
         text_document_sync: Some(TextDocumentSyncCapability::Options(TextDocumentSyncOptions {
             open_close: Some(true),
@@ -45,20 +49,7 @@ pub fn server_capabilities() -> ServerCapabilities {
         document_highlight_provider: Some(true),
         document_symbol_provider: Some(true),
         workspace_symbol_provider: Some(true),
-        code_action_provider: Some(CodeActionProviderCapability::Options(CodeActionOptions {
-            // Advertise support for all built-in CodeActionKinds
-            code_action_kinds: Some(vec![
-                lsp_types::code_action_kind::EMPTY.to_string(),
-                lsp_types::code_action_kind::QUICKFIX.to_string(),
-                lsp_types::code_action_kind::REFACTOR.to_string(),
-                lsp_types::code_action_kind::REFACTOR_EXTRACT.to_string(),
-                lsp_types::code_action_kind::REFACTOR_INLINE.to_string(),
-                lsp_types::code_action_kind::REFACTOR_REWRITE.to_string(),
-                lsp_types::code_action_kind::SOURCE.to_string(),
-                lsp_types::code_action_kind::SOURCE_ORGANIZE_IMPORTS.to_string(),
-            ]),
-            work_done_progress_options: Default::default(),
-        })),
+        code_action_provider: Some(code_action_provider),
         code_lens_provider: Some(CodeLensOptions { resolve_provider: Some(true) }),
         document_formatting_provider: Some(true),
         document_range_formatting_provider: None,
@@ -91,6 +82,35 @@ pub fn server_capabilities() -> ServerCapabilities {
             }
             .into(),
         ),
-        experimental: Default::default(),
+        experimental: Some(json!({
+            "joinLines": true,
+            "ssr": true,
+        })),
     }
 }
+
+fn code_action_capabilities(client_caps: &ClientCapabilities) -> CodeActionProviderCapability {
+    client_caps
+        .text_document
+        .as_ref()
+        .and_then(|it| it.code_action.as_ref())
+        .and_then(|it| it.code_action_literal_support.as_ref())
+        .map_or(CodeActionProviderCapability::Simple(true), |_| {
+            CodeActionProviderCapability::Options(CodeActionOptions {
+                // Advertise support for all built-in CodeActionKinds.
+                // Ideally we would base this off of the client capabilities
+                // but the client is supposed to fall back gracefully for unknown values.
+                code_action_kinds: Some(vec![
+                    lsp_types::code_action_kind::EMPTY.to_string(),
+                    lsp_types::code_action_kind::QUICKFIX.to_string(),
+                    lsp_types::code_action_kind::REFACTOR.to_string(),
+                    lsp_types::code_action_kind::REFACTOR_EXTRACT.to_string(),
+                    lsp_types::code_action_kind::REFACTOR_INLINE.to_string(),
+                    lsp_types::code_action_kind::REFACTOR_REWRITE.to_string(),
+                    lsp_types::code_action_kind::SOURCE.to_string(),
+                    lsp_types::code_action_kind::SOURCE_ORGANIZE_IMPORTS.to_string(),
+                ]),
+                work_done_progress_options: Default::default(),
+            })
+        })
+}
diff --git a/crates/rust-analyzer/src/cli/analysis_bench.rs b/crates/rust-analyzer/src/cli/analysis_bench.rs
index 6147ae207..b20efe98d 100644
--- a/crates/rust-analyzer/src/cli/analysis_bench.rs
+++ b/crates/rust-analyzer/src/cli/analysis_bench.rs
@@ -105,7 +105,7 @@ pub fn analysis_bench(
             if is_completion {
                 let options = CompletionConfig::default();
                 let res = do_work(&mut host, file_id, |analysis| {
-                    analysis.completions(file_position, &options)
+                    analysis.completions(&options, file_position)
                 });
                 if verbosity.is_verbose() {
                     println!("\n{:#?}", res);
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index b5dc6f0fa..c0f7c2c0c 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -11,7 +11,7 @@ use std::{ffi::OsString, path::PathBuf};
 
 use lsp_types::ClientCapabilities;
 use ra_flycheck::FlycheckConfig;
-use ra_ide::{CompletionConfig, InlayHintsConfig};
+use ra_ide::{AssistConfig, CompletionConfig, InlayHintsConfig};
 use ra_project_model::CargoConfig;
 use serde::Deserialize;
 
@@ -32,6 +32,7 @@ pub struct Config {
 
     pub inlay_hints: InlayHintsConfig,
     pub completion: CompletionConfig,
+    pub assist: AssistConfig,
     pub call_info_full: bool,
     pub lens: LensConfig,
 }
@@ -101,6 +102,7 @@ pub struct ClientCapsConfig {
     pub hierarchical_symbols: bool,
     pub code_action_literals: bool,
     pub work_done_progress: bool,
+    pub code_action_group: bool,
 }
 
 impl Default for Config {
@@ -136,6 +138,7 @@ impl Default for Config {
                 add_call_argument_snippets: true,
                 ..CompletionConfig::default()
             },
+            assist: AssistConfig::default(),
             call_info_full: true,
             lens: LensConfig::default(),
         }
@@ -266,13 +269,12 @@ impl Config {
             {
                 self.client_caps.hierarchical_symbols = value
             }
-            if let Some(value) = doc_caps
-                .code_action
-                .as_ref()
-                .and_then(|it| Some(it.code_action_literal_support.is_some()))
+            if let Some(value) =
+                doc_caps.code_action.as_ref().map(|it| it.code_action_literal_support.is_some())
             {
                 self.client_caps.code_action_literals = value;
             }
+
             self.completion.allow_snippets(false);
             if let Some(completion) = &doc_caps.completion {
                 if let Some(completion_item) = &completion.completion_item {
@@ -288,5 +290,16 @@ impl Config {
                 self.client_caps.work_done_progress = value;
             }
         }
+
+        self.assist.allow_snippets(false);
+        if let Some(experimental) = &caps.experimental {
+            let snippet_text_edit =
+                experimental.get("snippetTextEdit").and_then(|it| it.as_bool()) == Some(true);
+            self.assist.allow_snippets(snippet_text_edit);
+
+            let code_action_group =
+                experimental.get("codeActionGroup").and_then(|it| it.as_bool()) == Some(true);
+            self.client_caps.code_action_group = code_action_group
+        }
     }
 }
diff --git a/crates/rust-analyzer/src/diagnostics.rs b/crates/rust-analyzer/src/diagnostics.rs
index 4bdd45a7d..25856c543 100644
--- a/crates/rust-analyzer/src/diagnostics.rs
+++ b/crates/rust-analyzer/src/diagnostics.rs
@@ -3,9 +3,11 @@ pub(crate) mod to_proto;
 
 use std::{collections::HashMap, sync::Arc};
 
-use lsp_types::{CodeActionOrCommand, Diagnostic, Range};
+use lsp_types::{Diagnostic, Range};
 use ra_ide::FileId;
 
+use crate::lsp_ext;
+
 pub type CheckFixes = Arc<HashMap<FileId, Vec<Fix>>>;
 
 #[derive(Debug, Default, Clone)]
@@ -18,13 +20,13 @@ pub struct DiagnosticCollection {
 #[derive(Debug, Clone)]
 pub struct Fix {
     pub range: Range,
-    pub action: CodeActionOrCommand,
+    pub action: lsp_ext::CodeAction,
 }
 
 #[derive(Debug)]
 pub enum DiagnosticTask {
     ClearCheck,
-    AddCheck(FileId, Diagnostic, Vec<CodeActionOrCommand>),
+    AddCheck(FileId, Diagnostic, Vec<lsp_ext::CodeAction>),
     SetNative(FileId, Vec<Diagnostic>),
 }
 
@@ -38,7 +40,7 @@ impl DiagnosticCollection {
         &mut self,
         file_id: FileId,
         diagnostic: Diagnostic,
-        fixes: Vec<CodeActionOrCommand>,
+        fixes: Vec<lsp_ext::CodeAction>,
     ) {
         let diagnostics = self.check.entry(file_id).or_default();
         for existing_diagnostic in diagnostics.iter() {
diff --git a/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_multi_line_fix.snap b/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_multi_line_fix.snap
index 076b3cf27..c40cfdcdc 100644
--- a/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_multi_line_fix.snap
+++ b/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_multi_line_fix.snap
@@ -65,12 +65,13 @@ expression: diag
         fixes: [
             CodeAction {
                 title: "return the expression directly",
+                group: None,
                 kind: Some(
                     "quickfix",
                 ),
-                diagnostics: None,
+                command: None,
                 edit: Some(
-                    WorkspaceEdit {
+                    SnippetWorkspaceEdit {
                         changes: Some(
                             {
                                 "file:///test/src/main.rs": [
@@ -106,8 +107,6 @@ expression: diag
                         document_changes: None,
                     },
                 ),
-                command: None,
-                is_preferred: None,
             },
         ],
     },
diff --git a/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable.snap b/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable.snap
index 69138c15b..6dd3fcb2e 100644
--- a/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable.snap
+++ b/crates/rust-analyzer/src/diagnostics/snapshots/rust_analyzer__diagnostics__to_proto__tests__snap_rustc_unused_variable.snap
@@ -50,12 +50,13 @@ expression: diag
         fixes: [
             CodeAction {
                 title: "consider prefixing with an underscore",
+                group: None,
                 kind: Some(
                     "quickfix",
                 ),
-                diagnostics: None,
+                command: None,
                 edit: Some(
-                    WorkspaceEdit {
+                    SnippetWorkspaceEdit {
                         changes: Some(
                             {
                                 "file:///test/driver/subcommand/repl.rs": [
@@ -78,8 +79,6 @@ expression: diag
                         document_changes: None,
                     },
                 ),
-                command: None,
-                is_preferred: None,
             },
         ],
     },
diff --git a/crates/rust-analyzer/src/diagnostics/to_proto.rs b/crates/rust-analyzer/src/diagnostics/to_proto.rs
index eabf4908f..a500d670a 100644
--- a/crates/rust-analyzer/src/diagnostics/to_proto.rs
+++ b/crates/rust-analyzer/src/diagnostics/to_proto.rs
@@ -7,13 +7,13 @@ use std::{
 };
 
 use lsp_types::{
-    CodeAction, Diagnostic, DiagnosticRelatedInformation, DiagnosticSeverity, DiagnosticTag,
-    Location, NumberOrString, Position, Range, TextEdit, Url, WorkspaceEdit,
+    Diagnostic, DiagnosticRelatedInformation, DiagnosticSeverity, DiagnosticTag, Location,
+    NumberOrString, Position, Range, TextEdit, Url,
 };
 use ra_flycheck::{Applicability, DiagnosticLevel, DiagnosticSpan, DiagnosticSpanMacroExpansion};
 use stdx::format_to;
 
-use crate::Result;
+use crate::{lsp_ext, Result};
 
 /// Converts a Rust level string to a LSP severity
 fn map_level_to_severity(val: DiagnosticLevel) -> Option<DiagnosticSeverity> {
@@ -110,7 +110,7 @@ fn is_deprecated(rd: &ra_flycheck::Diagnostic) -> bool {
 
 enum MappedRustChildDiagnostic {
     Related(DiagnosticRelatedInformation),
-    SuggestedFix(CodeAction),
+    SuggestedFix(lsp_ext::CodeAction),
     MessageLine(String),
 }
 
@@ -143,13 +143,16 @@ fn map_rust_child_diagnostic(
             message: rd.message.clone(),
         })
     } else {
-        MappedRustChildDiagnostic::SuggestedFix(CodeAction {
+        MappedRustChildDiagnostic::SuggestedFix(lsp_ext::CodeAction {
             title: rd.message.clone(),
+            group: None,
             kind: Some("quickfix".to_string()),
-            diagnostics: None,
-            edit: Some(WorkspaceEdit::new(edit_map)),
+            edit: Some(lsp_ext::SnippetWorkspaceEdit {
+                // FIXME: there's no good reason to use edit_map here....
+                changes: Some(edit_map),
+                document_changes: None,
+            }),
             command: None,
-            is_preferred: None,
         })
     }
 }
@@ -158,7 +161,7 @@ fn map_rust_child_diagnostic(
 pub(crate) struct MappedRustDiagnostic {
     pub location: Location,
     pub diagnostic: Diagnostic,
-    pub fixes: Vec<CodeAction>,
+    pub fixes: Vec<lsp_ext::CodeAction>,
 }
 
 /// Converts a Rust root diagnostic to LSP form
diff --git a/crates/rust-analyzer/src/lsp_ext.rs b/crates/rust-analyzer/src/lsp_ext.rs
index 313a8c769..c25d90a50 100644
--- a/crates/rust-analyzer/src/lsp_ext.rs
+++ b/crates/rust-analyzer/src/lsp_ext.rs
@@ -1,6 +1,6 @@
 //! rust-analyzer extensions to the LSP.
 
-use std::path::PathBuf;
+use std::{collections::HashMap, path::PathBuf};
 
 use lsp_types::request::Request;
 use lsp_types::{Location, Position, Range, TextDocumentIdentifier};
@@ -87,22 +87,22 @@ pub enum JoinLines {}
 
 impl Request for JoinLines {
     type Params = JoinLinesParams;
-    type Result = SourceChange;
-    const METHOD: &'static str = "rust-analyzer/joinLines";
+    type Result = Vec<lsp_types::TextEdit>;
+    const METHOD: &'static str = "experimental/joinLines";
 }
 
 #[derive(Deserialize, Serialize, Debug)]
 #[serde(rename_all = "camelCase")]
 pub struct JoinLinesParams {
     pub text_document: TextDocumentIdentifier,
-    pub range: Range,
+    pub ranges: Vec<Range>,
 }
 
 pub enum OnEnter {}
 
 impl Request for OnEnter {
     type Params = lsp_types::TextDocumentPositionParams;
-    type Result = Option<SourceChange>;
+    type Result = Option<SnippetWorkspaceEdit>;
     const METHOD: &'static str = "rust-analyzer/onEnter";
 }
 
@@ -133,14 +133,6 @@ pub struct Runnable {
     pub cwd: Option<PathBuf>,
 }
 
-#[derive(Deserialize, Serialize, Debug)]
-#[serde(rename_all = "camelCase")]
-pub struct SourceChange {
-    pub label: String,
-    pub workspace_edit: lsp_types::WorkspaceEdit,
-    pub cursor_position: Option<lsp_types::TextDocumentPositionParams>,
-}
-
 pub enum InlayHints {}
 
 impl Request for InlayHints {
@@ -173,8 +165,8 @@ pub enum Ssr {}
 
 impl Request for Ssr {
     type Params = SsrParams;
-    type Result = SourceChange;
-    const METHOD: &'static str = "rust-analyzer/ssr";
+    type Result = lsp_types::WorkspaceEdit;
+    const METHOD: &'static str = "experimental/ssr";
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -183,3 +175,56 @@ pub struct SsrParams {
     pub query: String,
     pub parse_only: bool,
 }
+
+pub enum CodeActionRequest {}
+
+impl Request for CodeActionRequest {
+    type Params = lsp_types::CodeActionParams;
+    type Result = Option<Vec<CodeAction>>;
+    const METHOD: &'static str = "textDocument/codeAction";
+}
+
+#[derive(Debug, PartialEq, Clone, Default, Deserialize, Serialize)]
+pub struct CodeAction {
+    pub title: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub group: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub kind: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub command: Option<lsp_types::Command>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub edit: Option<SnippetWorkspaceEdit>,
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Default, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SnippetWorkspaceEdit {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub changes: Option<HashMap<lsp_types::Url, Vec<lsp_types::TextEdit>>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub document_changes: Option<Vec<SnippetDocumentChangeOperation>>,
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Deserialize, Serialize)]
+#[serde(untagged, rename_all = "lowercase")]
+pub enum SnippetDocumentChangeOperation {
+    Op(lsp_types::ResourceOp),
+    Edit(SnippetTextDocumentEdit),
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SnippetTextDocumentEdit {
+    pub text_document: lsp_types::VersionedTextDocumentIdentifier,
+    pub edits: Vec<SnippetTextEdit>,
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Default, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SnippetTextEdit {
+    pub range: Range,
+    pub new_text: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub insert_text_format: Option<lsp_types::InsertTextFormat>,
+}
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 15e5bb354..87795fffb 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -518,6 +518,7 @@ fn on_request(
         .on::<lsp_ext::ParentModule>(handlers::handle_parent_module)?
         .on::<lsp_ext::Runnables>(handlers::handle_runnables)?
         .on::<lsp_ext::InlayHints>(handlers::handle_inlay_hints)?
+        .on::<lsp_ext::CodeActionRequest>(handlers::handle_code_action)?
         .on::<lsp_types::request::OnTypeFormatting>(handlers::handle_on_type_formatting)?
         .on::<lsp_types::request::DocumentSymbolRequest>(handlers::handle_document_symbol)?
         .on::<lsp_types::request::WorkspaceSymbol>(handlers::handle_workspace_symbol)?
@@ -525,7 +526,6 @@ fn on_request(
         .on::<lsp_types::request::GotoImplementation>(handlers::handle_goto_implementation)?
         .on::<lsp_types::request::GotoTypeDefinition>(handlers::handle_goto_type_definition)?
         .on::<lsp_types::request::Completion>(handlers::handle_completion)?
-        .on::<lsp_types::request::CodeActionRequest>(handlers::handle_code_action)?
         .on::<lsp_types::request::CodeLensRequest>(handlers::handle_code_lens)?
         .on::<lsp_types::request::CodeLensResolve>(handlers::handle_code_lens_resolve)?
         .on::<lsp_types::request::FoldingRangeRequest>(handlers::handle_folding_range)?
diff --git a/crates/rust-analyzer/src/main_loop/handlers.rs b/crates/rust-analyzer/src/main_loop/handlers.rs
index e67556752..ba6857556 100644
--- a/crates/rust-analyzer/src/main_loop/handlers.rs
+++ b/crates/rust-analyzer/src/main_loop/handlers.rs
@@ -11,15 +11,15 @@ use lsp_server::ErrorCode;
 use lsp_types::{
     CallHierarchyIncomingCall, CallHierarchyIncomingCallsParams, CallHierarchyItem,
     CallHierarchyOutgoingCall, CallHierarchyOutgoingCallsParams, CallHierarchyPrepareParams,
-    CodeAction, CodeActionResponse, CodeLens, Command, CompletionItem, Diagnostic,
-    DocumentFormattingParams, DocumentHighlight, DocumentSymbol, FoldingRange, FoldingRangeParams,
-    Hover, HoverContents, Location, MarkupContent, MarkupKind, Position, PrepareRenameResponse,
-    Range, RenameParams, SemanticTokensParams, SemanticTokensRangeParams,
-    SemanticTokensRangeResult, SemanticTokensResult, SymbolInformation, TextDocumentIdentifier,
-    TextEdit, Url, WorkspaceEdit,
+    CodeLens, Command, CompletionItem, Diagnostic, DocumentFormattingParams, DocumentHighlight,
+    DocumentSymbol, FoldingRange, FoldingRangeParams, Hover, HoverContents, Location,
+    MarkupContent, MarkupKind, Position, PrepareRenameResponse, Range, RenameParams,
+    SemanticTokensParams, SemanticTokensRangeParams, SemanticTokensRangeResult,
+    SemanticTokensResult, SymbolInformation, TextDocumentIdentifier, Url, WorkspaceEdit,
 };
 use ra_ide::{
-    Assist, FileId, FilePosition, FileRange, Query, RangeInfo, Runnable, RunnableKind, SearchScope,
+    FileId, FilePosition, FileRange, Query, RangeInfo, Runnable, RunnableKind, SearchScope,
+    TextEdit,
 };
 use ra_prof::profile;
 use ra_project_model::TargetKind;
@@ -150,22 +150,35 @@ pub fn handle_find_matching_brace(
 pub fn handle_join_lines(
     world: WorldSnapshot,
     params: lsp_ext::JoinLinesParams,
-) -> Result<lsp_ext::SourceChange> {
+) -> Result<Vec<lsp_types::TextEdit>> {
     let _p = profile("handle_join_lines");
-    let frange = from_proto::file_range(&world, params.text_document, params.range)?;
-    let source_change = world.analysis().join_lines(frange)?;
-    to_proto::source_change(&world, source_change)
+    let file_id = from_proto::file_id(&world, &params.text_document.uri)?;
+    let line_index = world.analysis().file_line_index(file_id)?;
+    let line_endings = world.file_line_endings(file_id);
+    let mut res = TextEdit::default();
+    for range in params.ranges {
+        let range = from_proto::text_range(&line_index, range);
+        let edit = world.analysis().join_lines(FileRange { file_id, range })?;
+        match res.union(edit) {
+            Ok(()) => (),
+            Err(_edit) => {
+                // just ignore overlapping edits
+            }
+        }
+    }
+    let res = to_proto::text_edit_vec(&line_index, line_endings, res);
+    Ok(res)
 }
 
 pub fn handle_on_enter(
     world: WorldSnapshot,
     params: lsp_types::TextDocumentPositionParams,
-) -> Result<Option<lsp_ext::SourceChange>> {
+) -> Result<Option<lsp_ext::SnippetWorkspaceEdit>> {
     let _p = profile("handle_on_enter");
     let position = from_proto::file_position(&world, params)?;
     match world.analysis().on_enter(position)? {
         None => Ok(None),
-        Some(source_change) => to_proto::source_change(&world, source_change).map(Some),
+        Some(source_change) => to_proto::snippet_workspace_edit(&world, source_change).map(Some),
     }
 }
 
@@ -173,7 +186,7 @@ pub fn handle_on_enter(
 pub fn handle_on_type_formatting(
     world: WorldSnapshot,
     params: lsp_types::DocumentOnTypeFormattingParams,
-) -> Result<Option<Vec<TextEdit>>> {
+) -> Result<Option<Vec<lsp_types::TextEdit>>> {
     let _p = profile("handle_on_type_formatting");
     let mut position = from_proto::file_position(&world, params.text_document_position)?;
     let line_index = world.analysis().file_line_index(position.file_id)?;
@@ -268,7 +281,7 @@ pub fn handle_document_symbol(
             kind: symbol.kind,
             deprecated: symbol.deprecated,
             location: Location::new(url.clone(), symbol.range),
-            container_name: container_name,
+            container_name,
         });
 
         for child in symbol.children.iter().flatten() {
@@ -476,7 +489,7 @@ pub fn handle_completion(
         return Ok(None);
     }
 
-    let items = match world.analysis().completions(position, &world.config.completion)? {
+    let items = match world.analysis().completions(&world.config.completion, position)? {
         None => return Ok(None),
         Some(items) => items,
     };
@@ -585,9 +598,8 @@ pub fn handle_rename(world: WorldSnapshot, params: RenameParams) -> Result<Optio
         None => return Ok(None),
         Some(it) => it.info,
     };
-
-    let source_change = to_proto::source_change(&world, source_change)?;
-    Ok(Some(source_change.workspace_edit))
+    let workspace_edit = to_proto::workspace_edit(&world, source_change)?;
+    Ok(Some(workspace_edit))
 }
 
 pub fn handle_references(
@@ -620,7 +632,7 @@ pub fn handle_references(
 pub fn handle_formatting(
     world: WorldSnapshot,
     params: DocumentFormattingParams,
-) -> Result<Option<Vec<TextEdit>>> {
+) -> Result<Option<Vec<lsp_types::TextEdit>>> {
     let _p = profile("handle_formatting");
     let file_id = from_proto::file_id(&world, &params.text_document.uri)?;
     let file = world.analysis().file_text(file_id)?;
@@ -687,7 +699,7 @@ pub fn handle_formatting(
         }
     }
 
-    Ok(Some(vec![TextEdit {
+    Ok(Some(vec![lsp_types::TextEdit {
         range: Range::new(Position::new(0, 0), end_position),
         new_text: captured_stdout,
     }]))
@@ -696,14 +708,22 @@ pub fn handle_formatting(
 pub fn handle_code_action(
     world: WorldSnapshot,
     params: lsp_types::CodeActionParams,
-) -> Result<Option<CodeActionResponse>> {
+) -> Result<Option<Vec<lsp_ext::CodeAction>>> {
     let _p = profile("handle_code_action");
+    // We intentionally don't support command-based actions, as those either
+    // requires custom client-code anyway, or requires server-initiated edits.
+    // Server initiated edits break causality, so we avoid those as well.
+    if !world.config.client_caps.code_action_literals {
+        return Ok(None);
+    }
+
     let file_id = from_proto::file_id(&world, &params.text_document.uri)?;
     let line_index = world.analysis().file_line_index(file_id)?;
     let range = from_proto::text_range(&line_index, params.range);
+    let frange = FileRange { file_id, range };
 
     let diagnostics = world.analysis().diagnostics(file_id)?;
-    let mut res = CodeActionResponse::default();
+    let mut res: Vec<lsp_ext::CodeAction> = Vec::new();
 
     let fixes_from_diagnostics = diagnostics
         .into_iter()
@@ -711,24 +731,12 @@ pub fn handle_code_action(
         .filter(|(diag_range, _fix)| diag_range.intersect(range).is_some())
         .map(|(_range, fix)| fix);
 
-    for source_edit in fixes_from_diagnostics {
-        let title = source_edit.label.clone();
-        let edit = to_proto::source_change(&world, source_edit)?;
-
-        let command = Command {
-            title,
-            command: "rust-analyzer.applySourceChange".to_string(),
-            arguments: Some(vec![to_value(edit).unwrap()]),
-        };
-        let action = CodeAction {
-            title: command.title.clone(),
-            kind: None,
-            diagnostics: None,
-            edit: None,
-            command: Some(command),
-            is_preferred: None,
-        };
-        res.push(action.into());
+    for fix in fixes_from_diagnostics {
+        let title = fix.label;
+        let edit = to_proto::snippet_workspace_edit(&world, fix.source_change)?;
+        let action =
+            lsp_ext::CodeAction { title, group: None, kind: None, edit: Some(edit), command: None };
+        res.push(action);
     }
 
     for fix in world.check_fixes.get(&file_id).into_iter().flatten() {
@@ -739,70 +747,8 @@ pub fn handle_code_action(
         res.push(fix.action.clone());
     }
 
-    let mut grouped_assists: FxHashMap<String, (usize, Vec<Assist>)> = FxHashMap::default();
-    for assist in world.analysis().assists(FileRange { file_id, range })?.into_iter() {
-        match &assist.group_label {
-            Some(label) => grouped_assists
-                .entry(label.to_owned())
-                .or_insert_with(|| {
-                    let idx = res.len();
-                    let dummy = Command::new(String::new(), String::new(), None);
-                    res.push(dummy.into());
-                    (idx, Vec::new())
-                })
-                .1
-                .push(assist),
-            None => {
-                res.push(to_proto::code_action(&world, assist)?.into());
-            }
-        }
-    }
-
-    for (group_label, (idx, assists)) in grouped_assists {
-        if assists.len() == 1 {
-            res[idx] = to_proto::code_action(&world, assists.into_iter().next().unwrap())?.into();
-        } else {
-            let title = group_label;
-
-            let mut arguments = Vec::with_capacity(assists.len());
-            for assist in assists {
-                let source_change = to_proto::source_change(&world, assist.source_change)?;
-                arguments.push(to_value(source_change)?);
-            }
-
-            let command = Some(Command {
-                title: title.clone(),
-                command: "rust-analyzer.selectAndApplySourceChange".to_string(),
-                arguments: Some(vec![serde_json::Value::Array(arguments)]),
-            });
-            res[idx] = CodeAction {
-                title,
-                kind: None,
-                diagnostics: None,
-                edit: None,
-                command,
-                is_preferred: None,
-            }
-            .into();
-        }
-    }
-
-    // If the client only supports commands then filter the list
-    // and remove and actions that depend on edits.
-    if !world.config.client_caps.code_action_literals {
-        // FIXME: use drain_filter once it hits stable.
-        res = res
-            .into_iter()
-            .filter_map(|it| match it {
-                cmd @ lsp_types::CodeActionOrCommand::Command(_) => Some(cmd),
-                lsp_types::CodeActionOrCommand::CodeAction(action) => match action.command {
-                    Some(cmd) if action.edit.is_none() => {
-                        Some(lsp_types::CodeActionOrCommand::Command(cmd))
-                    }
-                    _ => None,
-                },
-            })
-            .collect();
+    for assist in world.analysis().assists(&world.config.assist, frange)?.into_iter() {
+        res.push(to_proto::code_action(&world, assist)?.into());
     }
     Ok(Some(res))
 }
@@ -828,11 +774,11 @@ pub fn handle_code_lens(
         for runnable in world.analysis().runnables(file_id)? {
             let (run_title, debugee) = match &runnable.kind {
                 RunnableKind::Test { .. } | RunnableKind::TestMod { .. } => {
-                    ("▶️\u{fe0e}Run Test", true)
+                    ("▶\u{fe0e} Run Test", true)
                 }
                 RunnableKind::DocTest { .. } => {
                     // cargo does not support -no-run for doctests
-                    ("▶️\u{fe0e}Run Doctest", false)
+                    ("▶\u{fe0e} Run Doctest", false)
                 }
                 RunnableKind::Bench { .. } => {
                     // Nothing wrong with bench debugging
@@ -998,11 +944,11 @@ pub fn handle_document_highlight(
 pub fn handle_ssr(
     world: WorldSnapshot,
     params: lsp_ext::SsrParams,
-) -> Result<lsp_ext::SourceChange> {
+) -> Result<lsp_types::WorkspaceEdit> {
     let _p = profile("handle_ssr");
     let source_change =
         world.analysis().structural_search_replace(&params.query, params.parse_only)??;
-    to_proto::source_change(&world, source_change)
+    to_proto::workspace_edit(&world, source_change)
 }
 
 pub fn publish_diagnostics(world: &WorldSnapshot, file_id: FileId) -> Result<DiagnosticTask> {
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 09343f925..672e47e41 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -1,13 +1,12 @@
 //! Conversion of rust-analyzer specific types to lsp_types equivalents.
 use ra_db::{FileId, FileRange};
 use ra_ide::{
-    translate_offset_with_edit, Assist, CompletionItem, CompletionItemKind, Documentation,
-    FileSystemEdit, Fold, FoldKind, FunctionSignature, Highlight, HighlightModifier, HighlightTag,
-    HighlightedRange, InlayHint, InlayKind, InsertTextFormat, LineIndex, NavigationTarget,
-    ReferenceAccess, Severity, SourceChange, SourceFileEdit,
+    Assist, CompletionItem, CompletionItemKind, Documentation, FileSystemEdit, Fold, FoldKind,
+    FunctionSignature, Highlight, HighlightModifier, HighlightTag, HighlightedRange, Indel,
+    InlayHint, InlayKind, InsertTextFormat, LineIndex, NavigationTarget, ReferenceAccess, Severity,
+    SourceChange, SourceFileEdit, TextEdit,
 };
 use ra_syntax::{SyntaxKind, TextRange, TextSize};
-use ra_text_edit::{Indel, TextEdit};
 use ra_vfs::LineEndings;
 
 use crate::{lsp_ext, semantic_tokens, world::WorldSnapshot, Result};
@@ -112,16 +111,28 @@ pub(crate) fn text_edit(
     lsp_types::TextEdit { range, new_text }
 }
 
+pub(crate) fn snippet_text_edit(
+    line_index: &LineIndex,
+    line_endings: LineEndings,
+    is_snippet: bool,
+    indel: Indel,
+) -> lsp_ext::SnippetTextEdit {
+    let text_edit = text_edit(line_index, line_endings, indel);
+    let insert_text_format =
+        if is_snippet { Some(lsp_types::InsertTextFormat::Snippet) } else { None };
+    lsp_ext::SnippetTextEdit {
+        range: text_edit.range,
+        new_text: text_edit.new_text,
+        insert_text_format,
+    }
+}
+
 pub(crate) fn text_edit_vec(
     line_index: &LineIndex,
     line_endings: LineEndings,
     text_edit: TextEdit,
 ) -> Vec<lsp_types::TextEdit> {
-    text_edit
-        .as_indels()
-        .iter()
-        .map(|it| self::text_edit(line_index, line_endings, it.clone()))
-        .collect()
+    text_edit.into_iter().map(|indel| self::text_edit(line_index, line_endings, indel)).collect()
 }
 
 pub(crate) fn completion_item(
@@ -134,7 +145,7 @@ pub(crate) fn completion_item(
     // LSP does not allow arbitrary edits in completion, so we have to do a
     // non-trivial mapping here.
     let source_range = completion_item.source_range();
-    for indel in completion_item.text_edit().as_indels() {
+    for indel in completion_item.text_edit().iter() {
         if indel.delete.contains_range(source_range) {
             text_edit = Some(if indel.delete == source_range {
                 self::text_edit(line_index, line_endings, indel.clone())
@@ -360,14 +371,6 @@ pub(crate) fn url(world: &WorldSnapshot, file_id: FileId) -> Result<lsp_types::U
     world.file_id_to_uri(file_id)
 }
 
-pub(crate) fn text_document_identifier(
-    world: &WorldSnapshot,
-    file_id: FileId,
-) -> Result<lsp_types::TextDocumentIdentifier> {
-    let res = lsp_types::TextDocumentIdentifier { uri: url(world, file_id)? };
-    Ok(res)
-}
-
 pub(crate) fn versioned_text_document_identifier(
     world: &WorldSnapshot,
     file_id: FileId,
@@ -442,20 +445,20 @@ pub(crate) fn goto_definition_response(
     }
 }
 
-pub(crate) fn text_document_edit(
+pub(crate) fn snippet_text_document_edit(
     world: &WorldSnapshot,
+    is_snippet: bool,
     source_file_edit: SourceFileEdit,
-) -> Result<lsp_types::TextDocumentEdit> {
+) -> Result<lsp_ext::SnippetTextDocumentEdit> {
     let text_document = versioned_text_document_identifier(world, source_file_edit.file_id, None)?;
     let line_index = world.analysis().file_line_index(source_file_edit.file_id)?;
     let line_endings = world.file_line_endings(source_file_edit.file_id);
     let edits = source_file_edit
         .edit
-        .as_indels()
-        .iter()
-        .map(|it| text_edit(&line_index, line_endings, it.clone()))
+        .into_iter()
+        .map(|it| snippet_text_edit(&line_index, line_endings, is_snippet, it))
         .collect();
-    Ok(lsp_types::TextDocumentEdit { text_document, edits })
+    Ok(lsp_ext::SnippetTextDocumentEdit { text_document, edits })
 }
 
 pub(crate) fn resource_op(
@@ -476,45 +479,65 @@ pub(crate) fn resource_op(
     Ok(res)
 }
 
-pub(crate) fn source_change(
+pub(crate) fn snippet_workspace_edit(
     world: &WorldSnapshot,
     source_change: SourceChange,
-) -> Result<lsp_ext::SourceChange> {
-    let cursor_position = match source_change.cursor_position {
-        None => None,
-        Some(pos) => {
-            let line_index = world.analysis().file_line_index(pos.file_id)?;
-            let edit = source_change
-                .source_file_edits
-                .iter()
-                .find(|it| it.file_id == pos.file_id)
-                .map(|it| &it.edit);
-            let line_col = match edit {
-                Some(edit) => translate_offset_with_edit(&*line_index, pos.offset, edit),
-                None => line_index.line_col(pos.offset),
-            };
-            let position =
-                lsp_types::Position::new(u64::from(line_col.line), u64::from(line_col.col_utf16));
-            Some(lsp_types::TextDocumentPositionParams {
-                text_document: text_document_identifier(world, pos.file_id)?,
-                position,
-            })
-        }
-    };
-    let mut document_changes: Vec<lsp_types::DocumentChangeOperation> = Vec::new();
+) -> Result<lsp_ext::SnippetWorkspaceEdit> {
+    let mut document_changes: Vec<lsp_ext::SnippetDocumentChangeOperation> = Vec::new();
     for op in source_change.file_system_edits {
         let op = resource_op(&world, op)?;
-        document_changes.push(lsp_types::DocumentChangeOperation::Op(op));
+        document_changes.push(lsp_ext::SnippetDocumentChangeOperation::Op(op));
     }
     for edit in source_change.source_file_edits {
-        let edit = text_document_edit(&world, edit)?;
-        document_changes.push(lsp_types::DocumentChangeOperation::Edit(edit));
+        let edit = snippet_text_document_edit(&world, source_change.is_snippet, edit)?;
+        document_changes.push(lsp_ext::SnippetDocumentChangeOperation::Edit(edit));
+    }
+    let workspace_edit =
+        lsp_ext::SnippetWorkspaceEdit { changes: None, document_changes: Some(document_changes) };
+    Ok(workspace_edit)
+}
+
+pub(crate) fn workspace_edit(
+    world: &WorldSnapshot,
+    source_change: SourceChange,
+) -> Result<lsp_types::WorkspaceEdit> {
+    assert!(!source_change.is_snippet);
+    snippet_workspace_edit(world, source_change).map(|it| it.into())
+}
+
+impl From<lsp_ext::SnippetWorkspaceEdit> for lsp_types::WorkspaceEdit {
+    fn from(snippet_workspace_edit: lsp_ext::SnippetWorkspaceEdit) -> lsp_types::WorkspaceEdit {
+        lsp_types::WorkspaceEdit {
+            changes: None,
+            document_changes: snippet_workspace_edit.document_changes.map(|changes| {
+                lsp_types::DocumentChanges::Operations(
+                    changes
+                        .into_iter()
+                        .map(|change| match change {
+                            lsp_ext::SnippetDocumentChangeOperation::Op(op) => {
+                                lsp_types::DocumentChangeOperation::Op(op)
+                            }
+                            lsp_ext::SnippetDocumentChangeOperation::Edit(edit) => {
+                                lsp_types::DocumentChangeOperation::Edit(
+                                    lsp_types::TextDocumentEdit {
+                                        text_document: edit.text_document,
+                                        edits: edit
+                                            .edits
+                                            .into_iter()
+                                            .map(|edit| lsp_types::TextEdit {
+                                                range: edit.range,
+                                                new_text: edit.new_text,
+                                            })
+                                            .collect(),
+                                    },
+                                )
+                            }
+                        })
+                        .collect(),
+                )
+            }),
+        }
     }
-    let workspace_edit = lsp_types::WorkspaceEdit {
-        changes: None,
-        document_changes: Some(lsp_types::DocumentChanges::Operations(document_changes)),
-    };
-    Ok(lsp_ext::SourceChange { label: source_change.label, workspace_edit, cursor_position })
 }
 
 pub fn call_hierarchy_item(
@@ -572,22 +595,13 @@ fn main() <fold>{
     }
 }
 
-pub(crate) fn code_action(world: &WorldSnapshot, assist: Assist) -> Result<lsp_types::CodeAction> {
-    let source_change = source_change(&world, assist.source_change)?;
-    let arg = serde_json::to_value(source_change)?;
-    let title = assist.label;
-    let command = lsp_types::Command {
-        title: title.clone(),
-        command: "rust-analyzer.applySourceChange".to_string(),
-        arguments: Some(vec![arg]),
-    };
-
-    Ok(lsp_types::CodeAction {
-        title,
+pub(crate) fn code_action(world: &WorldSnapshot, assist: Assist) -> Result<lsp_ext::CodeAction> {
+    let res = lsp_ext::CodeAction {
+        title: assist.label,
+        group: if world.config.client_caps.code_action_group { assist.group_label } else { None },
         kind: Some(String::new()),
-        diagnostics: None,
-        edit: None,
-        command: Some(command),
-        is_preferred: None,
-    })
+        edit: Some(snippet_workspace_edit(world, assist.source_change)?),
+        command: None,
+    };
+    Ok(res)
 }
diff --git a/crates/rust-analyzer/tests/heavy_tests/main.rs b/crates/rust-analyzer/tests/heavy_tests/main.rs
index 5011cc273..738a9a8e3 100644
--- a/crates/rust-analyzer/tests/heavy_tests/main.rs
+++ b/crates/rust-analyzer/tests/heavy_tests/main.rs
@@ -333,29 +333,17 @@ fn main() {}
             partial_result_params: PartialResultParams::default(),
             work_done_progress_params: WorkDoneProgressParams::default(),
         },
-        json!([
-          {
-            "command": {
-              "arguments": [
+        json!([{
+            "edit": {
+              "documentChanges": [
                 {
-                  "cursorPosition": null,
-                  "label": "Create module",
-                  "workspaceEdit": {
-                    "documentChanges": [
-                      {
-                        "kind": "create",
-                        "uri": "file:///[..]/src/bar.rs"
-                      }
-                    ]
-                  }
+                  "kind": "create",
+                  "uri": "file:///[..]/src/bar.rs"
                 }
-              ],
-              "command": "rust-analyzer.applySourceChange",
-              "title": "Create module"
+              ]
             },
             "title": "Create module"
-          }
-        ]),
+        }]),
     );
 
     server.request::<CodeActionRequest>(
@@ -416,29 +404,17 @@ fn main() {{}}
             partial_result_params: PartialResultParams::default(),
             work_done_progress_params: WorkDoneProgressParams::default(),
         },
-        json!([
-          {
-            "command": {
-              "arguments": [
+        json!([{
+            "edit": {
+              "documentChanges": [
                 {
-                  "cursorPosition": null,
-                  "label": "Create module",
-                  "workspaceEdit": {
-                    "documentChanges": [
-                      {
-                        "kind": "create",
-                        "uri": "file:///[..]/src/bar.rs"
-                      }
-                    ]
-                  }
+                  "kind": "create",
+                  "uri": "file://[..]/src/bar.rs"
                 }
-              ],
-              "command": "rust-analyzer.applySourceChange",
-              "title": "Create module"
+              ]
             },
             "title": "Create module"
-          }
-        ]),
+        }]),
     );
 
     server.request::<CodeActionRequest>(
@@ -498,27 +474,21 @@ fn main() {{}}
             position: Position { line: 0, character: 5 },
         },
         json!({
-          "cursorPosition": {
-            "position": { "character": 4, "line": 1 },
-            "textDocument": { "uri": "file:///[..]src/m0.rs" }
-          },
-          "label": "On enter",
-          "workspaceEdit": {
-            "documentChanges": [
-              {
-                "edits": [
-                  {
-                    "newText": "\n/// ",
-                    "range": {
-                      "end": { "character": 5, "line": 0 },
-                      "start": { "character": 5, "line": 0 }
-                    }
+          "documentChanges": [
+            {
+              "edits": [
+                {
+                  "insertTextFormat": 2,
+                  "newText": "\n/// $0",
+                  "range": {
+                    "end": { "character": 5, "line": 0 },
+                    "start": { "character": 5, "line": 0 }
                   }
-                ],
-                "textDocument": { "uri": "file:///[..]src/m0.rs", "version": null }
-              }
-            ]
-          }
+                }
+              ],
+              "textDocument": { "uri": "file:///[..]src/m0.rs", "version": null }
+            }
+          ]
         }),
     );
     let elapsed = start.elapsed();
@@ -550,27 +520,21 @@ version = \"0.0.0\"
             position: Position { line: 0, character: 8 },
         },
         json!({
-          "cursorPosition": {
-            "position": { "line": 1, "character": 4 },
-            "textDocument": { "uri": "file:///[..]src/main.rs" }
-          },
-          "label": "On enter",
-          "workspaceEdit": {
-            "documentChanges": [
-              {
-                "edits": [
-                  {
-                    "newText": "\r\n/// ",
-                    "range": {
-                      "end": { "line": 0, "character": 8 },
-                      "start": { "line": 0, "character": 8 }
-                    }
+          "documentChanges": [
+            {
+              "edits": [
+                {
+                  "insertTextFormat": 2,
+                  "newText": "\r\n/// $0",
+                  "range": {
+                    "end": { "line": 0, "character": 8 },
+                    "start": { "line": 0, "character": 8 }
                   }
-                ],
-                "textDocument": { "uri": "file:///[..]src/main.rs", "version": null }
-              }
-            ]
-          }
+                }
+              ],
+              "textDocument": { "uri": "file:///[..]src/main.rs", "version": null }
+            }
+          ]
         }),
     );
 }
@@ -810,5 +774,5 @@ pub fn foo(_input: TokenStream) -> TokenStream {
     });
 
     let value = res.get("contents").unwrap().get("value").unwrap().to_string();
-    assert_eq!(value, r#""```rust\nfoo::Bar\nfn bar()\n```""#)
+    assert_eq!(value, r#""foo::Bar\n___\n\n```rust\nfn bar()\n```""#)
 }
diff --git a/crates/stdx/src/lib.rs b/crates/stdx/src/lib.rs
index 0f34ce70e..71a57fba2 100644
--- a/crates/stdx/src/lib.rs
+++ b/crates/stdx/src/lib.rs
@@ -116,3 +116,11 @@ pub fn to_lower_snake_case(s: &str) -> String {
     }
     buf
 }
+
+pub fn replace(buf: &mut String, from: char, to: &str) {
+    if !buf.contains(from) {
+        return;
+    }
+    // FIXME: do this in place.
+    *buf = buf.replace(from, to)
+}
diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index b1e3c328f..be2cfbaa2 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -7,7 +7,7 @@
 //! * marks (see the eponymous module).
 
 #[macro_use]
-pub mod marks;
+pub mod mark;
 
 use std::{
     fs,
diff --git a/crates/test_utils/src/marks.rs b/crates/test_utils/src/mark.rs
index c3185e860..7c309a894 100644
--- a/crates/test_utils/src/marks.rs
+++ b/crates/test_utils/src/mark.rs
@@ -7,18 +7,18 @@
 //! ```
 //! #[test]
 //! fn test_foo() {
-//!     covers!(test_foo);
+//!     mark::check!(test_foo);
 //! }
 //! ```
 //!
 //! and in the code under test you write
 //!
 //! ```
-//! # use test_utils::tested_by;
+//! # use test_utils::mark;
 //! # fn some_condition() -> bool { true }
 //! fn foo() {
 //!     if some_condition() {
-//!         tested_by!(test_foo);
+//!         mark::hit!(test_foo);
 //!     }
 //! }
 //! ```
@@ -29,43 +29,31 @@
 use std::sync::atomic::{AtomicUsize, Ordering};
 
 #[macro_export]
-macro_rules! tested_by {
-    ($ident:ident; force) => {{
-        {
-            // sic! use call-site crate
-            crate::marks::$ident.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
-        }
-    }};
+macro_rules! _hit {
     ($ident:ident) => {{
         #[cfg(test)]
         {
-            // sic! use call-site crate
-            crate::marks::$ident.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
+            extern "C" {
+                #[no_mangle]
+                static $ident: std::sync::atomic::AtomicUsize;
+            }
+            unsafe {
+                $ident.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
+            }
         }
     }};
 }
+pub use _hit as hit;
 
 #[macro_export]
-macro_rules! covers {
-    // sic! use call-site crate
+macro_rules! _check {
     ($ident:ident) => {
-        $crate::covers!(crate::$ident)
-    };
-    ($krate:ident :: $ident:ident) => {
-        let _checker = $crate::marks::MarkChecker::new(&$krate::marks::$ident);
-    };
-}
-
-#[macro_export]
-macro_rules! marks {
-    ($($ident:ident)*) => {
-        $(
-        #[allow(bad_style)]
-        pub static $ident: std::sync::atomic::AtomicUsize =
-            std::sync::atomic::AtomicUsize::new(0);
-        )*
+        #[no_mangle]
+        static $ident: std::sync::atomic::AtomicUsize = std::sync::atomic::AtomicUsize::new(0);
+        let _checker = $crate::mark::MarkChecker::new(&$ident);
     };
 }
+pub use _check as check;
 
 pub struct MarkChecker {
     mark: &'static AtomicUsize,