38 files changed, 936 insertions, 203 deletions

diff --git a/crates/assists/src/handlers/merge_imports.rs b/crates/assists/src/handlers/merge_imports.rs
index 35b884206..0bd679260 100644
--- a/crates/assists/src/handlers/merge_imports.rs
+++ b/crates/assists/src/handlers/merge_imports.rs
@@ -1,14 +1,14 @@
-use std::iter::successors;
-
 use syntax::{
-    algo::{neighbor, skip_trivia_token, SyntaxRewriter},
-    ast::{self, edit::AstNodeEdit, make},
-    AstNode, Direction, InsertPosition, SyntaxElement, T,
+    algo::{neighbor, SyntaxRewriter},
+    ast, AstNode,
 };
 
 use crate::{
     assist_context::{AssistContext, Assists},
-    utils::next_prev,
+    utils::{
+        insert_use::{try_merge_imports, try_merge_trees},
+        next_prev, MergeBehaviour,
+    },
     AssistId, AssistKind,
 };
 
@@ -30,23 +30,22 @@ pub(crate) fn merge_imports(acc: &mut Assists, ctx: &AssistContext) -> Option<()
     let mut offset = ctx.offset();
 
     if let Some(use_item) = tree.syntax().parent().and_then(ast::Use::cast) {
-        let (merged, to_delete) = next_prev()
-            .filter_map(|dir| neighbor(&use_item, dir))
-            .filter_map(|it| Some((it.clone(), it.use_tree()?)))
-            .find_map(|(use_item, use_tree)| {
-                Some((try_merge_trees(&tree, &use_tree)?, use_item))
+        let (merged, to_delete) =
+            next_prev().filter_map(|dir| neighbor(&use_item, dir)).find_map(|use_item2| {
+                try_merge_imports(&use_item, &use_item2, MergeBehaviour::Full).zip(Some(use_item2))
             })?;
 
-        rewriter.replace_ast(&tree, &merged);
+        rewriter.replace_ast(&use_item, &merged);
         rewriter += to_delete.remove();
 
         if to_delete.syntax().text_range().end() < offset {
             offset -= to_delete.syntax().text_range().len();
         }
     } else {
-        let (merged, to_delete) = next_prev()
-            .filter_map(|dir| neighbor(&tree, dir))
-            .find_map(|use_tree| Some((try_merge_trees(&tree, &use_tree)?, use_tree.clone())))?;
+        let (merged, to_delete) =
+            next_prev().filter_map(|dir| neighbor(&tree, dir)).find_map(|use_tree| {
+                try_merge_trees(&tree, &use_tree, MergeBehaviour::Full).zip(Some(use_tree))
+            })?;
 
         rewriter.replace_ast(&tree, &merged);
         rewriter += to_delete.remove();
@@ -67,66 +66,6 @@ pub(crate) fn merge_imports(acc: &mut Assists, ctx: &AssistContext) -> Option<()
     )
 }
 
-fn try_merge_trees(old: &ast::UseTree, new: &ast::UseTree) -> Option<ast::UseTree> {
-    let lhs_path = old.path()?;
-    let rhs_path = new.path()?;
-
-    let (lhs_prefix, rhs_prefix) = common_prefix(&lhs_path, &rhs_path)?;
-
-    let lhs = old.split_prefix(&lhs_prefix);
-    let rhs = new.split_prefix(&rhs_prefix);
-
-    let should_insert_comma = lhs
-        .use_tree_list()?
-        .r_curly_token()
-        .and_then(|it| skip_trivia_token(it.prev_token()?, Direction::Prev))
-        .map(|it| it.kind() != T![,])
-        .unwrap_or(true);
-
-    let mut to_insert: Vec<SyntaxElement> = Vec::new();
-    if should_insert_comma {
-        to_insert.push(make::token(T![,]).into());
-        to_insert.push(make::tokens::single_space().into());
-    }
-    to_insert.extend(
-        rhs.use_tree_list()?
-            .syntax()
-            .children_with_tokens()
-            .filter(|it| it.kind() != T!['{'] && it.kind() != T!['}']),
-    );
-    let use_tree_list = lhs.use_tree_list()?;
-    let pos = InsertPosition::Before(use_tree_list.r_curly_token()?.into());
-    let use_tree_list = use_tree_list.insert_children(pos, to_insert);
-    Some(lhs.with_use_tree_list(use_tree_list))
-}
-
-fn common_prefix(lhs: &ast::Path, rhs: &ast::Path) -> Option<(ast::Path, ast::Path)> {
-    let mut res = None;
-    let mut lhs_curr = first_path(&lhs);
-    let mut rhs_curr = first_path(&rhs);
-    loop {
-        match (lhs_curr.segment(), rhs_curr.segment()) {
-            (Some(lhs), Some(rhs)) if lhs.syntax().text() == rhs.syntax().text() => (),
-            _ => break,
-        }
-        res = Some((lhs_curr.clone(), rhs_curr.clone()));
-
-        match (lhs_curr.parent_path(), rhs_curr.parent_path()) {
-            (Some(lhs), Some(rhs)) => {
-                lhs_curr = lhs;
-                rhs_curr = rhs;
-            }
-            _ => break,
-        }
-    }
-
-    res
-}
-
-fn first_path(path: &ast::Path) -> ast::Path {
-    successors(Some(path.clone()), |it| it.qualifier()).last().unwrap()
-}
-
 #[cfg(test)]
 mod tests {
     use crate::tests::{check_assist, check_assist_not_applicable};
@@ -189,6 +128,78 @@ use std::{fmt::{Display, self}};
     }
 
     #[test]
+    fn skip_pub1() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+pub use std::fmt<|>::Debug;
+use std::fmt::Display;
+",
+        );
+    }
+
+    #[test]
+    fn skip_pub_last() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+use std::fmt<|>::Debug;
+pub use std::fmt::Display;
+",
+        );
+    }
+
+    #[test]
+    fn skip_pub_crate_pub() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+pub(crate) use std::fmt<|>::Debug;
+pub use std::fmt::Display;
+",
+        );
+    }
+
+    #[test]
+    fn skip_pub_pub_crate() {
+        check_assist_not_applicable(
+            merge_imports,
+            r"
+pub use std::fmt<|>::Debug;
+pub(crate) use std::fmt::Display;
+",
+        );
+    }
+
+    #[test]
+    fn merge_pub() {
+        check_assist(
+            merge_imports,
+            r"
+pub use std::fmt<|>::Debug;
+pub use std::fmt::Display;
+",
+            r"
+pub use std::fmt::{Debug, Display};
+",
+        )
+    }
+
+    #[test]
+    fn merge_pub_crate() {
+        check_assist(
+            merge_imports,
+            r"
+pub(crate) use std::fmt<|>::Debug;
+pub(crate) use std::fmt::Display;
+",
+            r"
+pub(crate) use std::fmt::{Debug, Display};
+",
+        )
+    }
+
+    #[test]
     fn test_merge_nested() {
         check_assist(
             merge_imports,
diff --git a/crates/assists/src/handlers/remove_dbg.rs b/crates/assists/src/handlers/remove_dbg.rs
index 4e252edf0..a8ab2aecc 100644
--- a/crates/assists/src/handlers/remove_dbg.rs
+++ b/crates/assists/src/handlers/remove_dbg.rs
@@ -1,6 +1,6 @@
 use syntax::{
     ast::{self, AstNode},
-    TextRange, TextSize, T,
+    SyntaxElement, TextRange, TextSize, T,
 };
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
@@ -22,62 +22,108 @@ use crate::{AssistContext, AssistId, AssistKind, Assists};
 // ```
 pub(crate) fn remove_dbg(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
     let macro_call = ctx.find_node_at_offset::<ast::MacroCall>()?;
+    let new_contents = adjusted_macro_contents(&macro_call)?;
 
-    if !is_valid_macrocall(&macro_call, "dbg")? {
-        return None;
-    }
-
-    let is_leaf = macro_call.syntax().next_sibling().is_none();
-
+    let macro_text_range = macro_call.syntax().text_range();
     let macro_end = if macro_call.semicolon_token().is_some() {
-        macro_call.syntax().text_range().end() - TextSize::of(';')
+        macro_text_range.end() - TextSize::of(';')
     } else {
-        macro_call.syntax().text_range().end()
+        macro_text_range.end()
     };
 
-    // macro_range determines what will be deleted and replaced with macro_content
-    let macro_range = TextRange::new(macro_call.syntax().text_range().start(), macro_end);
-    let paste_instead_of_dbg = {
-        let text = macro_call.token_tree()?.syntax().text();
-
-        // leafiness determines if we should include the parenthesis or not
-        let slice_index: TextRange = if is_leaf {
-            // leaf means - we can extract the contents of the dbg! in text
-            TextRange::new(TextSize::of('('), text.len() - TextSize::of(')'))
-        } else {
-            // not leaf - means we should keep the parens
-            TextRange::up_to(text.len())
-        };
-        text.slice(slice_index).to_string()
-    };
+    acc.add(
+        AssistId("remove_dbg", AssistKind::Refactor),
+        "Remove dbg!()",
+        macro_text_range,
+        |builder| {
+            builder.replace(TextRange::new(macro_text_range.start(), macro_end), new_contents);
+        },
+    )
+}
 
-    let target = macro_call.syntax().text_range();
-    acc.add(AssistId("remove_dbg", AssistKind::Refactor), "Remove dbg!()", target, |builder| {
-        builder.replace(macro_range, paste_instead_of_dbg);
+fn adjusted_macro_contents(macro_call: &ast::MacroCall) -> Option<String> {
+    let contents = get_valid_macrocall_contents(&macro_call, "dbg")?;
+    let macro_text_with_brackets = macro_call.token_tree()?.syntax().text();
+    let macro_text_in_brackets = macro_text_with_brackets.slice(TextRange::new(
+        TextSize::of('('),
+        macro_text_with_brackets.len() - TextSize::of(')'),
+    ));
+
+    let is_leaf = macro_call.syntax().next_sibling().is_none();
+    Some(if !is_leaf && needs_parentheses_around_macro_contents(contents) {
+        format!("({})", macro_text_in_brackets)
+    } else {
+        macro_text_in_brackets.to_string()
     })
 }
 
 /// Verifies that the given macro_call actually matches the given name
-/// and contains proper ending tokens
-fn is_valid_macrocall(macro_call: &ast::MacroCall, macro_name: &str) -> Option<bool> {
+/// and contains proper ending tokens, then returns the contents between the ending tokens
+fn get_valid_macrocall_contents(
+    macro_call: &ast::MacroCall,
+    macro_name: &str,
+) -> Option<Vec<SyntaxElement>> {
     let path = macro_call.path()?;
     let name_ref = path.segment()?.name_ref()?;
 
     // Make sure it is actually a dbg-macro call, dbg followed by !
     let excl = path.syntax().next_sibling_or_token()?;
-
     if name_ref.text() != macro_name || excl.kind() != T![!] {
         return None;
     }
 
-    let node = macro_call.token_tree()?.syntax().clone();
-    let first_child = node.first_child_or_token()?;
-    let last_child = node.last_child_or_token()?;
+    let mut children_with_tokens = macro_call.token_tree()?.syntax().children_with_tokens();
+    let first_child = children_with_tokens.next()?;
+    let mut contents_between_brackets = children_with_tokens.collect::<Vec<_>>();
+    let last_child = contents_between_brackets.pop()?;
+
+    if contents_between_brackets.is_empty() {
+        None
+    } else {
+        match (first_child.kind(), last_child.kind()) {
+            (T!['('], T![')']) | (T!['['], T![']']) | (T!['{'], T!['}']) => {
+                Some(contents_between_brackets)
+            }
+            _ => None,
+        }
+    }
+}
 
-    match (first_child.kind(), last_child.kind()) {
-        (T!['('], T![')']) | (T!['['], T![']']) | (T!['{'], T!['}']) => Some(true),
-        _ => Some(false),
+fn needs_parentheses_around_macro_contents(macro_contents: Vec<SyntaxElement>) -> bool {
+    if macro_contents.len() < 2 {
+        return false;
     }
+    let mut unpaired_brackets_in_contents = Vec::new();
+    for element in macro_contents {
+        match element.kind() {
+            T!['('] | T!['['] | T!['{'] => unpaired_brackets_in_contents.push(element),
+            T![')'] => {
+                if !matches!(unpaired_brackets_in_contents.pop(), Some(correct_bracket) if correct_bracket.kind() == T!['('])
+                {
+                    return true;
+                }
+            }
+            T![']'] => {
+                if !matches!(unpaired_brackets_in_contents.pop(), Some(correct_bracket) if correct_bracket.kind() == T!['['])
+                {
+                    return true;
+                }
+            }
+            T!['}'] => {
+                if !matches!(unpaired_brackets_in_contents.pop(), Some(correct_bracket) if correct_bracket.kind() == T!['{'])
+                {
+                    return true;
+                }
+            }
+            symbol_kind => {
+                let symbol_not_in_bracket = unpaired_brackets_in_contents.is_empty();
+                if symbol_not_in_bracket && symbol_kind.is_punct() {
+                    return true;
+                }
+            }
+        }
+    }
+    !unpaired_brackets_in_contents.is_empty()
 }
 
 #[cfg(test)]
@@ -157,12 +203,38 @@ fn foo(n: usize) {
     }
 
     #[test]
+    fn remove_dbg_from_non_leaf_simple_expression() {
+        check_assist(
+            remove_dbg,
+            "
+fn main() {
+    let mut a = 1;
+    while dbg!<|>(a) < 10000 {
+        a += 1;
+    }
+}
+",
+            "
+fn main() {
+    let mut a = 1;
+    while a < 10000 {
+        a += 1;
+    }
+}
+",
+        );
+    }
+
+    #[test]
     fn test_remove_dbg_keep_expression() {
         check_assist(
             remove_dbg,
             r#"let res = <|>dbg!(a + b).foo();"#,
             r#"let res = (a + b).foo();"#,
         );
+
+        check_assist(remove_dbg, r#"let res = <|>dbg!(2 + 2) * 5"#, r#"let res = (2 + 2) * 5"#);
+        check_assist(remove_dbg, r#"let res = <|>dbg![2 + 2] * 5"#, r#"let res = (2 + 2) * 5"#);
     }
 
     #[test]
diff --git a/crates/assists/src/utils/insert_use.rs b/crates/assists/src/utils/insert_use.rs
index 8a4c8520d..98553b2e0 100644
--- a/crates/assists/src/utils/insert_use.rs
+++ b/crates/assists/src/utils/insert_use.rs
@@ -138,13 +138,23 @@ pub(crate) fn insert_use(
     algo::insert_children(scope.as_syntax_node(), insert_position, to_insert)
 }
 
-fn try_merge_imports(
+fn eq_visibility(vis0: Option<ast::Visibility>, vis1: Option<ast::Visibility>) -> bool {
+    match (vis0, vis1) {
+        (None, None) => true,
+        // FIXME: Don't use the string representation to check for equality
+        // spaces inside of the node would break this comparison
+        (Some(vis0), Some(vis1)) => vis0.to_string() == vis1.to_string(),
+        _ => false,
+    }
+}
+
+pub(crate) fn try_merge_imports(
     old: &ast::Use,
     new: &ast::Use,
     merge_behaviour: MergeBehaviour,
 ) -> Option<ast::Use> {
-    // don't merge into re-exports
-    if old.visibility().and_then(|vis| vis.pub_token()).is_some() {
+    // don't merge imports with different visibilities
+    if !eq_visibility(old.visibility(), new.visibility()) {
         return None;
     }
     let old_tree = old.use_tree()?;
@@ -161,7 +171,7 @@ fn use_tree_list_is_nested(tl: &ast::UseTreeList) -> bool {
 }
 
 // FIXME: currently this merely prepends the new tree into old, ideally it would insert the items in a sorted fashion
-pub fn try_merge_trees(
+pub(crate) fn try_merge_trees(
     old: &ast::UseTree,
     new: &ast::UseTree,
     merge_behaviour: MergeBehaviour,
@@ -278,7 +288,8 @@ fn first_path(path: &ast::Path) -> ast::Path {
 }
 
 fn segment_iter(path: &ast::Path) -> impl Iterator<Item = ast::PathSegment> + Clone {
-    path.syntax().children().flat_map(ast::PathSegment::cast)
+    // cant make use of SyntaxNode::siblings, because the returned Iterator is not clone
+    successors(first_segment(path), |p| p.parent_path().parent_path().and_then(|p| p.segment()))
 }
 
 #[derive(PartialEq, Eq)]
@@ -684,8 +695,18 @@ use std::io;",
         check_last(
             "foo::bar",
             r"use foo::bar::baz::Qux;",
-            r"use foo::bar::baz::Qux;
-use foo::bar;",
+            r"use foo::bar;
+use foo::bar::baz::Qux;",
+        );
+    }
+
+    #[test]
+    fn insert_short_before_long() {
+        check_none(
+            "foo::bar",
+            r"use foo::bar::baz::Qux;",
+            r"use foo::bar;
+use foo::bar::baz::Qux;",
         );
     }
 
diff --git a/crates/base_db/src/input.rs b/crates/base_db/src/input.rs
index f3d65cdf0..9a61f1d56 100644
--- a/crates/base_db/src/input.rs
+++ b/crates/base_db/src/input.rs
@@ -12,7 +12,7 @@ use cfg::CfgOptions;
 use rustc_hash::{FxHashMap, FxHashSet};
 use syntax::SmolStr;
 use tt::TokenExpander;
-use vfs::file_set::FileSet;
+use vfs::{file_set::FileSet, VfsPath};
 
 pub use vfs::FileId;
 
@@ -43,6 +43,12 @@ impl SourceRoot {
     pub fn new_library(file_set: FileSet) -> SourceRoot {
         SourceRoot { is_library: true, file_set }
     }
+    pub fn path_for_file(&self, file: &FileId) -> Option<&VfsPath> {
+        self.file_set.path_for_file(file)
+    }
+    pub fn file_for_path(&self, path: &VfsPath) -> Option<&FileId> {
+        self.file_set.file_for_path(path)
+    }
     pub fn iter(&self) -> impl Iterator<Item = FileId> + '_ {
         self.file_set.iter()
     }
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index 1594d4f0f..0516a05b4 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -207,8 +207,8 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.resolve_record_field(field)
     }
 
-    pub fn resolve_record_field_pat(&self, field: &ast::RecordPatField) -> Option<Field> {
-        self.imp.resolve_record_field_pat(field)
+    pub fn resolve_record_pat_field(&self, field: &ast::RecordPatField) -> Option<Field> {
+        self.imp.resolve_record_pat_field(field)
     }
 
     pub fn resolve_macro_call(&self, macro_call: &ast::MacroCall) -> Option<MacroDef> {
@@ -433,8 +433,8 @@ impl<'db> SemanticsImpl<'db> {
         self.analyze(field.syntax()).resolve_record_field(self.db, field)
     }
 
-    fn resolve_record_field_pat(&self, field: &ast::RecordPatField) -> Option<Field> {
-        self.analyze(field.syntax()).resolve_record_field_pat(self.db, field)
+    fn resolve_record_pat_field(&self, field: &ast::RecordPatField) -> Option<Field> {
+        self.analyze(field.syntax()).resolve_record_pat_field(self.db, field)
     }
 
     fn resolve_macro_call(&self, macro_call: &ast::MacroCall) -> Option<MacroDef> {
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index 1d13c4f1d..1aef0f33f 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -179,13 +179,13 @@ impl SourceAnalyzer {
         Some((struct_field.into(), local))
     }
 
-    pub(crate) fn resolve_record_field_pat(
+    pub(crate) fn resolve_record_pat_field(
         &self,
         _db: &dyn HirDatabase,
         field: &ast::RecordPatField,
     ) -> Option<Field> {
         let pat_id = self.pat_id(&field.pat()?)?;
-        let struct_field = self.infer.as_ref()?.record_field_pat_resolution(pat_id)?;
+        let struct_field = self.infer.as_ref()?.record_pat_field_resolution(pat_id)?;
         Some(struct_field.into())
     }
 
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index c5ebc2aa0..2d91bb21f 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -838,8 +838,12 @@ impl ExprCollector<'_> {
 
                 Pat::Missing
             }
+            ast::Pat::BoxPat(boxpat) => {
+                let inner = self.collect_pat_opt(boxpat.pat());
+                Pat::Box { inner }
+            }
             // FIXME: implement
-            ast::Pat::BoxPat(_) | ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) => Pat::Missing,
+            ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) => Pat::Missing,
         };
         let ptr = AstPtr::new(&pat);
         self.alloc_pat(pattern, Either::Left(ptr))
diff --git a/crates/hir_def/src/expr.rs b/crates/hir_def/src/expr.rs
index e862c2080..e5d740a36 100644
--- a/crates/hir_def/src/expr.rs
+++ b/crates/hir_def/src/expr.rs
@@ -398,6 +398,7 @@ pub enum Pat {
     Bind { mode: BindingAnnotation, name: Name, subpat: Option<PatId> },
     TupleStruct { path: Option<Path>, args: Vec<PatId>, ellipsis: Option<usize> },
     Ref { pat: PatId, mutability: Mutability },
+    Box { inner: PatId },
 }
 
 impl Pat {
@@ -418,6 +419,7 @@ impl Pat {
             Pat::Record { args, .. } => {
                 args.iter().map(|f| f.pat).for_each(f);
             }
+            Pat::Box { inner } => f(*inner),
         }
     }
 }
diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index 03b00b101..2b53b8297 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -125,7 +125,7 @@ pub struct InferenceResult {
     field_resolutions: FxHashMap<ExprId, FieldId>,
     /// For each field in record literal, records the field it resolves to.
     record_field_resolutions: FxHashMap<ExprId, FieldId>,
-    record_field_pat_resolutions: FxHashMap<PatId, FieldId>,
+    record_pat_field_resolutions: FxHashMap<PatId, FieldId>,
     /// For each struct literal, records the variant it resolves to.
     variant_resolutions: FxHashMap<ExprOrPatId, VariantId>,
     /// For each associated item record what it resolves to
@@ -146,8 +146,8 @@ impl InferenceResult {
     pub fn record_field_resolution(&self, expr: ExprId) -> Option<FieldId> {
         self.record_field_resolutions.get(&expr).copied()
     }
-    pub fn record_field_pat_resolution(&self, pat: PatId) -> Option<FieldId> {
-        self.record_field_pat_resolutions.get(&pat).copied()
+    pub fn record_pat_field_resolution(&self, pat: PatId) -> Option<FieldId> {
+        self.record_pat_field_resolutions.get(&pat).copied()
     }
     pub fn variant_resolution_for_expr(&self, id: ExprId) -> Option<VariantId> {
         self.variant_resolutions.get(&id.into()).copied()
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index 4dd4f9802..cde2ab82b 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -70,7 +70,7 @@ impl<'a> InferenceContext<'a> {
             let matching_field = var_data.as_ref().and_then(|it| it.field(&subpat.name));
             if let Some(local_id) = matching_field {
                 let field_def = FieldId { parent: def.unwrap(), local_id };
-                self.result.record_field_pat_resolutions.insert(subpat.pat, field_def);
+                self.result.record_pat_field_resolutions.insert(subpat.pat, field_def);
             }
 
             let expected_ty =
@@ -209,6 +209,18 @@ impl<'a> InferenceContext<'a> {
                 end_ty
             }
             Pat::Lit(expr) => self.infer_expr(*expr, &Expectation::has_type(expected.clone())),
+            Pat::Box { inner } => match self.resolve_boxed_box() {
+                Some(box_adt) => {
+                    let inner_expected = match expected.as_adt() {
+                        Some((adt, substs)) if adt == box_adt => substs.as_single(),
+                        _ => &Ty::Unknown,
+                    };
+
+                    let inner_ty = self.infer_pat(*inner, inner_expected, default_bm);
+                    Ty::apply_one(TypeCtor::Adt(box_adt), inner_ty)
+                }
+                None => Ty::Unknown,
+            },
             Pat::Missing => Ty::Unknown,
         };
         // use a new type variable if we got Ty::Unknown here
@@ -236,6 +248,6 @@ fn is_non_ref_pat(body: &hir_def::body::Body, pat: PatId) -> bool {
             Expr::Literal(Literal::String(..)) => false,
             _ => true,
         },
-        Pat::Wild | Pat::Bind { .. } | Pat::Ref { .. } | Pat::Missing => false,
+        Pat::Wild | Pat::Bind { .. } | Pat::Ref { .. } | Pat::Box { .. } | Pat::Missing => false,
     }
 }
diff --git a/crates/hir_ty/src/tests/patterns.rs b/crates/hir_ty/src/tests/patterns.rs
index aeb191c79..6a965ac4f 100644
--- a/crates/hir_ty/src/tests/patterns.rs
+++ b/crates/hir_ty/src/tests/patterns.rs
@@ -654,3 +654,28 @@ fn slice_tail_pattern() {
         "#]],
     );
 }
+
+#[test]
+fn box_pattern() {
+    check_infer(
+        r#"
+        #[lang = "owned_box"]
+        pub struct Box<T>(T);
+
+        fn foo(params: Box<i32>) {
+            match params {
+                box integer => {}
+            }
+        }
+        "#,
+        expect![[r#"
+            52..58 'params': Box<i32>
+            70..124 '{     ...   } }': ()
+            76..122 'match ...     }': ()
+            82..88 'params': Box<i32>
+            99..110 'box integer': Box<i32>
+            103..110 'integer': i32
+            114..116 '{}': ()
+        "#]],
+    );
+}
diff --git a/crates/hir_ty/src/traits/chalk.rs b/crates/hir_ty/src/traits/chalk.rs
index ff364789e..57d0a32df 100644
--- a/crates/hir_ty/src/traits/chalk.rs
+++ b/crates/hir_ty/src/traits/chalk.rs
@@ -307,13 +307,17 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         let id = from_chalk(self.db, trait_id);
         self.db.trait_data(id).name.to_string()
     }
-    // FIXME: lookup names
-    fn adt_name(&self, struct_id: chalk_ir::AdtId<Interner>) -> String {
-        let datum = self.db.struct_datum(self.krate, struct_id);
-        format!("{:?}", datum.name(&Interner))
+    fn adt_name(&self, adt_id: chalk_ir::AdtId<Interner>) -> String {
+        let id = from_chalk(self.db, adt_id);
+        match id {
+            hir_def::AdtId::StructId(id) => self.db.struct_data(id).name.to_string(),
+            hir_def::AdtId::EnumId(id) => self.db.enum_data(id).name.to_string(),
+            hir_def::AdtId::UnionId(id) => self.db.union_data(id).name.to_string(),
+        }
     }
     fn assoc_type_name(&self, assoc_ty_id: chalk_ir::AssocTypeId<Interner>) -> String {
-        format!("Assoc_{}", assoc_ty_id.0)
+        let id = self.db.associated_ty_data(assoc_ty_id).name;
+        self.db.type_alias_data(id).name.to_string()
     }
     fn opaque_type_name(&self, opaque_ty_id: chalk_ir::OpaqueTyId<Interner>) -> String {
         format!("Opaque_{}", opaque_ty_id.0)
diff --git a/crates/hir_ty/src/traits/chalk/interner.rs b/crates/hir_ty/src/traits/chalk/interner.rs
index fc0f9c201..eb35db3ff 100644
--- a/crates/hir_ty/src/traits/chalk/interner.rs
+++ b/crates/hir_ty/src/traits/chalk/interner.rs
@@ -26,7 +26,7 @@ pub type OpaqueTyId = chalk_ir::OpaqueTyId<Interner>;
 pub type OpaqueTyDatum = chalk_solve::rust_ir::OpaqueTyDatum<Interner>;
 
 impl chalk_ir::interner::Interner for Interner {
-    type InternedType = Box<chalk_ir::TyData<Self>>; // FIXME use Arc?
+    type InternedType = Arc<chalk_ir::TyData<Self>>;
     type InternedLifetime = chalk_ir::LifetimeData<Self>;
     type InternedConst = Arc<chalk_ir::ConstData<Self>>;
     type InternedConcreteConst = ();
@@ -34,7 +34,7 @@ impl chalk_ir::interner::Interner for Interner {
     type InternedGoal = Arc<GoalData<Self>>;
     type InternedGoals = Vec<Goal<Self>>;
     type InternedSubstitution = Vec<GenericArg<Self>>;
-    type InternedProgramClause = chalk_ir::ProgramClauseData<Self>;
+    type InternedProgramClause = Arc<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>>;
@@ -197,11 +197,11 @@ impl chalk_ir::interner::Interner for Interner {
         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 intern_ty(&self, ty: chalk_ir::TyData<Self>) -> Arc<chalk_ir::TyData<Self>> {
+        Arc::new(ty)
     }
 
-    fn ty_data<'a>(&self, ty: &'a Box<chalk_ir::TyData<Self>>) -> &'a chalk_ir::TyData<Self> {
+    fn ty_data<'a>(&self, ty: &'a Arc<chalk_ir::TyData<Self>>) -> &'a chalk_ir::TyData<Self> {
         ty
     }
 
@@ -230,7 +230,7 @@ impl chalk_ir::interner::Interner for Interner {
         constant
     }
 
-    fn const_eq(&self, _ty: &Box<chalk_ir::TyData<Self>>, _c1: &(), _c2: &()) -> bool {
+    fn const_eq(&self, _ty: &Arc<chalk_ir::TyData<Self>>, _c1: &(), _c2: &()) -> bool {
         true
     }
 
@@ -284,13 +284,13 @@ impl chalk_ir::interner::Interner for Interner {
     fn intern_program_clause(
         &self,
         data: chalk_ir::ProgramClauseData<Self>,
-    ) -> chalk_ir::ProgramClauseData<Self> {
-        data
+    ) -> Arc<chalk_ir::ProgramClauseData<Self>> {
+        Arc::new(data)
     }
 
     fn program_clause_data<'a>(
         &self,
-        clause: &'a chalk_ir::ProgramClauseData<Self>,
+        clause: &'a Arc<chalk_ir::ProgramClauseData<Self>>,
     ) -> &'a chalk_ir::ProgramClauseData<Self> {
         clause
     }
diff --git a/crates/hir_ty/src/traits/chalk/mapping.rs b/crates/hir_ty/src/traits/chalk/mapping.rs
index fe62f3fa7..d6bacba1d 100644
--- a/crates/hir_ty/src/traits/chalk/mapping.rs
+++ b/crates/hir_ty/src/traits/chalk/mapping.rs
@@ -464,6 +464,18 @@ impl ToChalk for hir_def::ImplId {
     }
 }
 
+impl ToChalk for hir_def::AdtId {
+    type Chalk = AdtId;
+
+    fn to_chalk(self, _db: &dyn HirDatabase) -> Self::Chalk {
+        chalk_ir::AdtId(self.into())
+    }
+
+    fn from_chalk(_db: &dyn HirDatabase, id: AdtId) -> Self {
+        id.0
+    }
+}
+
 impl ToChalk for CallableDefId {
     type Chalk = FnDefId;
 
diff --git a/crates/ide/src/completion.rs b/crates/ide/src/completion.rs
index 33bed6991..daea2aa95 100644
--- a/crates/ide/src/completion.rs
+++ b/crates/ide/src/completion.rs
@@ -19,6 +19,7 @@ mod complete_unqualified_path;
 mod complete_postfix;
 mod complete_macro_in_item_position;
 mod complete_trait_impl;
+mod complete_mod;
 
 use ide_db::RootDatabase;
 
@@ -124,6 +125,7 @@ pub(crate) fn completions(
     complete_postfix::complete_postfix(&mut acc, &ctx);
     complete_macro_in_item_position::complete_macro_in_item_position(&mut acc, &ctx);
     complete_trait_impl::complete_trait_impl(&mut acc, &ctx);
+    complete_mod::complete_mod(&mut acc, &ctx);
 
     Some(acc)
 }
diff --git a/crates/ide/src/completion/complete_attribute.rs b/crates/ide/src/completion/complete_attribute.rs
index 0abfaebcb..f4a9864d1 100644
--- a/crates/ide/src/completion/complete_attribute.rs
+++ b/crates/ide/src/completion/complete_attribute.rs
@@ -13,6 +13,10 @@ use crate::completion::{
 };
 
 pub(super) fn complete_attribute(acc: &mut Completions, ctx: &CompletionContext) -> Option<()> {
+    if ctx.mod_declaration_under_caret.is_some() {
+        return None;
+    }
+
     let attribute = ctx.attribute_under_caret.as_ref()?;
     match (attribute.path(), attribute.token_tree()) {
         (Some(path), Some(token_tree)) if path.to_string() == "derive" => {
diff --git a/crates/ide/src/completion/complete_mod.rs b/crates/ide/src/completion/complete_mod.rs
new file mode 100644
index 000000000..3cfc2e131
--- /dev/null
+++ b/crates/ide/src/completion/complete_mod.rs
@@ -0,0 +1,324 @@
+//! Completes mod declarations.
+
+use base_db::{SourceDatabaseExt, VfsPath};
+use hir::{Module, ModuleSource};
+use ide_db::RootDatabase;
+use rustc_hash::FxHashSet;
+
+use crate::{CompletionItem, CompletionItemKind};
+
+use super::{
+    completion_context::CompletionContext, completion_item::CompletionKind,
+    completion_item::Completions,
+};
+
+/// Complete mod declaration, i.e. `mod <|> ;`
+pub(super) fn complete_mod(acc: &mut Completions, ctx: &CompletionContext) -> Option<()> {
+    let mod_under_caret = match &ctx.mod_declaration_under_caret {
+        Some(mod_under_caret) if mod_under_caret.item_list().is_some() => return None,
+        Some(mod_under_caret) => mod_under_caret,
+        None => return None,
+    };
+
+    let _p = profile::span("completion::complete_mod");
+
+    let current_module = ctx.scope.module()?;
+
+    let module_definition_file =
+        current_module.definition_source(ctx.db).file_id.original_file(ctx.db);
+    let source_root = ctx.db.source_root(ctx.db.file_source_root(module_definition_file));
+    let directory_to_look_for_submodules = directory_to_look_for_submodules(
+        current_module,
+        ctx.db,
+        source_root.path_for_file(&module_definition_file)?,
+    )?;
+
+    let existing_mod_declarations = current_module
+        .children(ctx.db)
+        .filter_map(|module| Some(module.name(ctx.db)?.to_string()))
+        .collect::<FxHashSet<_>>();
+
+    let module_declaration_file =
+        current_module.declaration_source(ctx.db).map(|module_declaration_source_file| {
+            module_declaration_source_file.file_id.original_file(ctx.db)
+        });
+
+    source_root
+        .iter()
+        .filter(|submodule_candidate_file| submodule_candidate_file != &module_definition_file)
+        .filter(|submodule_candidate_file| {
+            Some(submodule_candidate_file) != module_declaration_file.as_ref()
+        })
+        .filter_map(|submodule_file| {
+            let submodule_path = source_root.path_for_file(&submodule_file)?;
+            let directory_with_submodule = submodule_path.parent()?;
+            match submodule_path.name_and_extension()? {
+                ("lib", Some("rs")) | ("main", Some("rs")) => None,
+                ("mod", Some("rs")) => {
+                    if directory_with_submodule.parent()? == directory_to_look_for_submodules {
+                        match directory_with_submodule.name_and_extension()? {
+                            (directory_name, None) => Some(directory_name.to_owned()),
+                            _ => None,
+                        }
+                    } else {
+                        None
+                    }
+                }
+                (file_name, Some("rs"))
+                    if directory_with_submodule == directory_to_look_for_submodules =>
+                {
+                    Some(file_name.to_owned())
+                }
+                _ => None,
+            }
+        })
+        .filter(|name| !existing_mod_declarations.contains(name))
+        .for_each(|submodule_name| {
+            let mut label = submodule_name;
+            if mod_under_caret.semicolon_token().is_none() {
+                label.push(';')
+            }
+            acc.add(
+                CompletionItem::new(CompletionKind::Magic, ctx.source_range(), &label)
+                    .kind(CompletionItemKind::Module),
+            )
+        });
+
+    Some(())
+}
+
+fn directory_to_look_for_submodules(
+    module: Module,
+    db: &RootDatabase,
+    module_file_path: &VfsPath,
+) -> Option<VfsPath> {
+    let directory_with_module_path = module_file_path.parent()?;
+    let base_directory = match module_file_path.name_and_extension()? {
+        ("mod", Some("rs")) | ("lib", Some("rs")) | ("main", Some("rs")) => {
+            Some(directory_with_module_path)
+        }
+        (regular_rust_file_name, Some("rs")) => {
+            if matches!(
+                (
+                    directory_with_module_path
+                        .parent()
+                        .as_ref()
+                        .and_then(|path| path.name_and_extension()),
+                    directory_with_module_path.name_and_extension(),
+                ),
+                (Some(("src", None)), Some(("bin", None)))
+            ) {
+                // files in /src/bin/ can import each other directly
+                Some(directory_with_module_path)
+            } else {
+                directory_with_module_path.join(regular_rust_file_name)
+            }
+        }
+        _ => None,
+    }?;
+
+    let mut resulting_path = base_directory;
+    for module in module_chain_to_containing_module_file(module, db) {
+        if let Some(name) = module.name(db) {
+            resulting_path = resulting_path.join(&name.to_string())?;
+        }
+    }
+
+    Some(resulting_path)
+}
+
+fn module_chain_to_containing_module_file(
+    current_module: Module,
+    db: &RootDatabase,
+) -> Vec<Module> {
+    let mut path = Vec::new();
+
+    let mut current_module = Some(current_module);
+    while let Some(ModuleSource::Module(_)) =
+        current_module.map(|module| module.definition_source(db).value)
+    {
+        if let Some(module) = current_module {
+            path.insert(0, module);
+            current_module = module.parent(db);
+        } else {
+            current_module = None;
+        }
+    }
+
+    path
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::completion::{test_utils::completion_list, CompletionKind};
+    use expect_test::{expect, Expect};
+
+    fn check(ra_fixture: &str, expect: Expect) {
+        let actual = completion_list(ra_fixture, CompletionKind::Magic);
+        expect.assert_eq(&actual);
+    }
+
+    #[test]
+    fn lib_module_completion() {
+        check(
+            r#"
+            //- /lib.rs
+            mod <|>
+            //- /foo.rs
+            fn foo() {}
+            //- /foo/ignored_foo.rs
+            fn ignored_foo() {}
+            //- /bar/mod.rs
+            fn bar() {}
+            //- /bar/ignored_bar.rs
+            fn ignored_bar() {}
+        "#,
+            expect![[r#"
+                md bar;
+                md foo;
+            "#]],
+        );
+    }
+
+    #[test]
+    fn no_module_completion_with_module_body() {
+        check(
+            r#"
+            //- /lib.rs
+            mod <|> {
+
+            }
+            //- /foo.rs
+            fn foo() {}
+        "#,
+            expect![[r#""#]],
+        );
+    }
+
+    #[test]
+    fn main_module_completion() {
+        check(
+            r#"
+            //- /main.rs
+            mod <|>
+            //- /foo.rs
+            fn foo() {}
+            //- /foo/ignored_foo.rs
+            fn ignored_foo() {}
+            //- /bar/mod.rs
+            fn bar() {}
+            //- /bar/ignored_bar.rs
+            fn ignored_bar() {}
+        "#,
+            expect![[r#"
+                md bar;
+                md foo;
+            "#]],
+        );
+    }
+
+    #[test]
+    fn main_test_module_completion() {
+        check(
+            r#"
+            //- /main.rs
+            mod tests {
+                mod <|>;
+            }
+            //- /tests/foo.rs
+            fn foo() {}
+        "#,
+            expect![[r#"
+                md foo
+            "#]],
+        );
+    }
+
+    #[test]
+    fn directly_nested_module_completion() {
+        check(
+            r#"
+            //- /lib.rs
+            mod foo;
+            //- /foo.rs
+            mod <|>;
+            //- /foo/bar.rs
+            fn bar() {}
+            //- /foo/bar/ignored_bar.rs
+            fn ignored_bar() {}
+            //- /foo/baz/mod.rs
+            fn baz() {}
+            //- /foo/moar/ignored_moar.rs
+            fn ignored_moar() {}
+        "#,
+            expect![[r#"
+                md bar
+                md baz
+            "#]],
+        );
+    }
+
+    #[test]
+    fn nested_in_source_module_completion() {
+        check(
+            r#"
+            //- /lib.rs
+            mod foo;
+            //- /foo.rs
+            mod bar {
+                mod <|>
+            }
+            //- /foo/bar/baz.rs
+            fn baz() {}
+        "#,
+            expect![[r#"
+                md baz;
+            "#]],
+        );
+    }
+
+    // FIXME binary modules are not supported in tests properly
+    // Binary modules are a bit special, they allow importing the modules from `/src/bin`
+    // and that's why are good to test two things:
+    // * no cycles are allowed in mod declarations
+    // * no modules from the parent directory are proposed
+    // Unfortunately, binary modules support is in cargo not rustc,
+    // hence the test does not work now
+    //
+    // #[test]
+    // fn regular_bin_module_completion() {
+    //     check(
+    //         r#"
+    //         //- /src/bin.rs
+    //         fn main() {}
+    //         //- /src/bin/foo.rs
+    //         mod <|>
+    //         //- /src/bin/bar.rs
+    //         fn bar() {}
+    //         //- /src/bin/bar/bar_ignored.rs
+    //         fn bar_ignored() {}
+    //     "#,
+    //         expect![[r#"
+    //             md bar;
+    //         "#]],
+    //     );
+    // }
+
+    #[test]
+    fn already_declared_bin_module_completion_omitted() {
+        check(
+            r#"
+            //- /src/bin.rs
+            fn main() {}
+            //- /src/bin/foo.rs
+            mod <|>
+            //- /src/bin/bar.rs
+            mod foo;
+            fn bar() {}
+            //- /src/bin/bar/bar_ignored.rs
+            fn bar_ignored() {}
+        "#,
+            expect![[r#""#]],
+        );
+    }
+}
diff --git a/crates/ide/src/completion/complete_qualified_path.rs b/crates/ide/src/completion/complete_qualified_path.rs
index accb09f7e..79de50792 100644
--- a/crates/ide/src/completion/complete_qualified_path.rs
+++ b/crates/ide/src/completion/complete_qualified_path.rs
@@ -13,7 +13,7 @@ pub(super) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
         None => return,
     };
 
-    if ctx.attribute_under_caret.is_some() {
+    if ctx.attribute_under_caret.is_some() || ctx.mod_declaration_under_caret.is_some() {
         return;
     }
 
diff --git a/crates/ide/src/completion/complete_unqualified_path.rs b/crates/ide/src/completion/complete_unqualified_path.rs
index 1f1b682a7..8eda4b64d 100644
--- a/crates/ide/src/completion/complete_unqualified_path.rs
+++ b/crates/ide/src/completion/complete_unqualified_path.rs
@@ -13,6 +13,7 @@ pub(super) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
     if ctx.record_lit_syntax.is_some()
         || ctx.record_pat_syntax.is_some()
         || ctx.attribute_under_caret.is_some()
+        || ctx.mod_declaration_under_caret.is_some()
     {
         return;
     }
diff --git a/crates/ide/src/completion/completion_context.rs b/crates/ide/src/completion/completion_context.rs
index 47355d5dc..161f59c1e 100644
--- a/crates/ide/src/completion/completion_context.rs
+++ b/crates/ide/src/completion/completion_context.rs
@@ -77,6 +77,7 @@ pub(crate) struct CompletionContext<'a> {
     pub(super) is_path_type: bool,
     pub(super) has_type_args: bool,
     pub(super) attribute_under_caret: Option<ast::Attr>,
+    pub(super) mod_declaration_under_caret: Option<ast::Module>,
     pub(super) unsafe_is_prev: bool,
     pub(super) if_is_prev: bool,
     pub(super) block_expr_parent: bool,
@@ -152,6 +153,7 @@ impl<'a> CompletionContext<'a> {
             has_type_args: false,
             dot_receiver_is_ambiguous_float_literal: false,
             attribute_under_caret: None,
+            mod_declaration_under_caret: None,
             unsafe_is_prev: false,
             in_loop_body: false,
             ref_pat_parent: false,
@@ -238,7 +240,10 @@ impl<'a> CompletionContext<'a> {
         self.trait_as_prev_sibling = has_trait_as_prev_sibling(syntax_element.clone());
         self.is_match_arm = is_match_arm(syntax_element.clone());
         self.has_item_list_or_source_file_parent =
-            has_item_list_or_source_file_parent(syntax_element);
+            has_item_list_or_source_file_parent(syntax_element.clone());
+        self.mod_declaration_under_caret =
+            find_node_at_offset::<ast::Module>(&file_with_fake_ident, offset)
+                .filter(|module| module.item_list().is_none());
     }
 
     fn fill(
diff --git a/crates/ide/src/completion/patterns.rs b/crates/ide/src/completion/patterns.rs
index c6ae589db..b17ddf133 100644
--- a/crates/ide/src/completion/patterns.rs
+++ b/crates/ide/src/completion/patterns.rs
@@ -115,6 +115,7 @@ pub(crate) fn if_is_prev(element: SyntaxElement) -> bool {
         .filter(|it| it.kind() == IF_KW)
         .is_some()
 }
+
 #[test]
 fn test_if_is_prev() {
     check_pattern_is_applicable(r"if l<|>", if_is_prev);
diff --git a/crates/ide/src/syntax_highlighting.rs b/crates/ide/src/syntax_highlighting.rs
index 25d6f7abd..d9fc25d88 100644
--- a/crates/ide/src/syntax_highlighting.rs
+++ b/crates/ide/src/syntax_highlighting.rs
@@ -4,7 +4,7 @@ mod injection;
 #[cfg(test)]
 mod tests;
 
-use hir::{Name, Semantics, VariantDef};
+use hir::{Local, Name, Semantics, VariantDef};
 use ide_db::{
     defs::{classify_name, classify_name_ref, Definition, NameClass, NameRefClass},
     RootDatabase,
@@ -13,8 +13,8 @@ use rustc_hash::FxHashMap;
 use syntax::{
     ast::{self, HasFormatSpecifier},
     AstNode, AstToken, Direction, NodeOrToken, SyntaxElement,
-    SyntaxKind::*,
-    TextRange, WalkEvent, T,
+    SyntaxKind::{self, *},
+    SyntaxNode, SyntaxToken, TextRange, WalkEvent, T,
 };
 
 use crate::FileId;
@@ -454,6 +454,32 @@ fn macro_call_range(macro_call: &ast::MacroCall) -> Option<TextRange> {
     Some(TextRange::new(range_start, range_end))
 }
 
+/// Returns true if the parent nodes of `node` all match the `SyntaxKind`s in `kinds` exactly.
+fn parents_match(mut node: NodeOrToken<SyntaxNode, SyntaxToken>, mut kinds: &[SyntaxKind]) -> bool {
+    while let (Some(parent), [kind, rest @ ..]) = (&node.parent(), kinds) {
+        if parent.kind() != *kind {
+            return false;
+        }
+
+        // FIXME: Would be nice to get parent out of the match, but binding by-move and by-value
+        // in the same pattern is unstable: rust-lang/rust#68354.
+        node = node.parent().unwrap().into();
+        kinds = rest;
+    }
+
+    // Only true if we matched all expected kinds
+    kinds.len() == 0
+}
+
+fn is_consumed_lvalue(
+    node: NodeOrToken<SyntaxNode, SyntaxToken>,
+    local: &Local,
+    db: &RootDatabase,
+) -> bool {
+    // When lvalues are passed as arguments and they're not Copy, then mark them as Consuming.
+    parents_match(node, &[PATH_SEGMENT, PATH, PATH_EXPR, ARG_LIST]) && !local.ty(db).is_copy(db)
+}
+
 fn highlight_element(
     sema: &Semantics<RootDatabase>,
     bindings_shadow_count: &mut FxHashMap<Name, u32>,
@@ -522,6 +548,12 @@ fn highlight_element(
 
                             let mut h = highlight_def(db, def);
 
+                            if let Definition::Local(local) = &def {
+                                if is_consumed_lvalue(name_ref.syntax().clone().into(), local, db) {
+                                    h |= HighlightModifier::Consuming;
+                                }
+                            }
+
                             if let Some(parent) = name_ref.syntax().parent() {
                                 if matches!(parent.kind(), FIELD_EXPR | RECORD_PAT_FIELD) {
                                     if let Definition::Field(field) = def {
@@ -645,21 +677,30 @@ fn highlight_element(
                         .and_then(ast::SelfParam::cast)
                         .and_then(|p| p.mut_token())
                         .is_some();
-                    // closure to enforce lazyness
-                    let self_path = || {
-                        sema.resolve_path(&element.parent()?.parent().and_then(ast::Path::cast)?)
-                    };
+                    let self_path = &element
+                        .parent()
+                        .as_ref()
+                        .and_then(SyntaxNode::parent)
+                        .and_then(ast::Path::cast)
+                        .and_then(|p| sema.resolve_path(&p));
+                    let mut h = HighlightTag::SelfKeyword.into();
                     if self_param_is_mut
-                        || matches!(self_path(),
+                        || matches!(self_path,
                             Some(hir::PathResolution::Local(local))
                                 if local.is_self(db)
                                     && (local.is_mut(db) || local.ty(db).is_mutable_reference())
                         )
                     {
-                        HighlightTag::SelfKeyword | HighlightModifier::Mutable
-                    } else {
-                        HighlightTag::SelfKeyword.into()
+                        h |= HighlightModifier::Mutable
                     }
+
+                    if let Some(hir::PathResolution::Local(local)) = self_path {
+                        if is_consumed_lvalue(element, &local, db) {
+                            h |= HighlightModifier::Consuming;
+                        }
+                    }
+
+                    h
                 }
                 T![ref] => element
                     .parent()
diff --git a/crates/ide/src/syntax_highlighting/test_data/highlighting.html b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
index d0df2e0ec..cde42024c 100644
--- a/crates/ide/src/syntax_highlighting/test_data/highlighting.html
+++ b/crates/ide/src/syntax_highlighting/test_data/highlighting.html
@@ -61,8 +61,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 <span class="punctuation">}</span>
 
 <span class="keyword">impl</span> <span class="struct">Foo</span> <span class="punctuation">{</span>
-    <span class="keyword">fn</span> <span class="function declaration">baz</span><span class="punctuation">(</span><span class="keyword">mut</span> <span class="self_keyword mutable">self</span><span class="punctuation">)</span> <span class="operator">-&gt;</span> <span class="builtin_type">i32</span> <span class="punctuation">{</span>
-        <span class="self_keyword">self</span><span class="punctuation">.</span><span class="field">x</span>
+    <span class="keyword">fn</span> <span class="function declaration">baz</span><span class="punctuation">(</span><span class="keyword">mut</span> <span class="self_keyword mutable">self</span><span class="punctuation">,</span> <span class="value_param declaration">f</span><span class="punctuation">:</span> <span class="struct">Foo</span><span class="punctuation">)</span> <span class="operator">-&gt;</span> <span class="builtin_type">i32</span> <span class="punctuation">{</span>
+        <span class="value_param">f</span><span class="punctuation">.</span><span class="function consuming">baz</span><span class="punctuation">(</span><span class="self_keyword consuming">self</span><span class="punctuation">)</span>
     <span class="punctuation">}</span>
 
     <span class="keyword">fn</span> <span class="function declaration">qux</span><span class="punctuation">(</span><span class="operator">&</span><span class="keyword">mut</span> <span class="self_keyword mutable">self</span><span class="punctuation">)</span> <span class="punctuation">{</span>
@@ -80,8 +80,8 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 <span class="punctuation">}</span>
 
 <span class="keyword">impl</span> <span class="struct">FooCopy</span> <span class="punctuation">{</span>
-    <span class="keyword">fn</span> <span class="function declaration">baz</span><span class="punctuation">(</span><span class="self_keyword">self</span><span class="punctuation">)</span> <span class="operator">-&gt;</span> <span class="builtin_type">u32</span> <span class="punctuation">{</span>
-        <span class="self_keyword">self</span><span class="punctuation">.</span><span class="field">x</span>
+    <span class="keyword">fn</span> <span class="function declaration">baz</span><span class="punctuation">(</span><span class="self_keyword">self</span><span class="punctuation">,</span> <span class="value_param declaration">f</span><span class="punctuation">:</span> <span class="struct">FooCopy</span><span class="punctuation">)</span> <span class="operator">-&gt;</span> <span class="builtin_type">u32</span> <span class="punctuation">{</span>
+        <span class="value_param">f</span><span class="punctuation">.</span><span class="function">baz</span><span class="punctuation">(</span><span class="self_keyword">self</span><span class="punctuation">)</span>
     <span class="punctuation">}</span>
 
     <span class="keyword">fn</span> <span class="function declaration">qux</span><span class="punctuation">(</span><span class="operator">&</span><span class="keyword">mut</span> <span class="self_keyword mutable">self</span><span class="punctuation">)</span> <span class="punctuation">{</span>
@@ -144,14 +144,15 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
     <span class="variable">y</span><span class="punctuation">;</span>
 
     <span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable declaration mutable">foo</span> <span class="operator">=</span> <span class="struct">Foo</span> <span class="punctuation">{</span> <span class="field">x</span><span class="punctuation">,</span> <span class="field">y</span><span class="punctuation">:</span> <span class="variable mutable">x</span> <span class="punctuation">}</span><span class="punctuation">;</span>
+    <span class="keyword">let</span> <span class="variable declaration">foo2</span> <span class="operator">=</span> <span class="variable mutable">foo</span><span class="punctuation">.</span><span class="unresolved_reference">clone</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
     <span class="variable mutable">foo</span><span class="punctuation">.</span><span class="function">quop</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
     <span class="variable mutable">foo</span><span class="punctuation">.</span><span class="function mutable">qux</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
-    <span class="variable mutable">foo</span><span class="punctuation">.</span><span class="function consuming">baz</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
+    <span class="variable mutable">foo</span><span class="punctuation">.</span><span class="function consuming">baz</span><span class="punctuation">(</span><span class="variable consuming">foo2</span><span class="punctuation">)</span><span class="punctuation">;</span>
 
     <span class="keyword">let</span> <span class="keyword">mut</span> <span class="variable declaration mutable">copy</span> <span class="operator">=</span> <span class="struct">FooCopy</span> <span class="punctuation">{</span> <span class="field">x</span> <span class="punctuation">}</span><span class="punctuation">;</span>
     <span class="variable mutable">copy</span><span class="punctuation">.</span><span class="function">quop</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
     <span class="variable mutable">copy</span><span class="punctuation">.</span><span class="function mutable">qux</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
-    <span class="variable mutable">copy</span><span class="punctuation">.</span><span class="function">baz</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
+    <span class="variable mutable">copy</span><span class="punctuation">.</span><span class="function">baz</span><span class="punctuation">(</span><span class="variable mutable">copy</span><span class="punctuation">)</span><span class="punctuation">;</span>
 <span class="punctuation">}</span>
 
 <span class="keyword">enum</span> <span class="enum declaration">Option</span><span class="punctuation">&lt;</span><span class="type_param declaration">T</span><span class="punctuation">&gt;</span> <span class="punctuation">{</span>
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index 6f72a29bd..57d4e1252 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -35,8 +35,8 @@ impl Bar for Foo {
 }
 
 impl Foo {
-    fn baz(mut self) -> i32 {
-        self.x
+    fn baz(mut self, f: Foo) -> i32 {
+        f.baz(self)
     }
 
     fn qux(&mut self) {
@@ -54,8 +54,8 @@ struct FooCopy {
 }
 
 impl FooCopy {
-    fn baz(self) -> u32 {
-        self.x
+    fn baz(self, f: FooCopy) -> u32 {
+        f.baz(self)
     }
 
     fn qux(&mut self) {
@@ -118,14 +118,15 @@ fn main() {
     y;
 
     let mut foo = Foo { x, y: x };
+    let foo2 = foo.clone();
     foo.quop();
     foo.qux();
-    foo.baz();
+    foo.baz(foo2);
 
     let mut copy = FooCopy { x };
     copy.quop();
     copy.qux();
-    copy.baz();
+    copy.baz(copy);
 }
 
 enum Option<T> {
diff --git a/crates/ide_db/src/defs.rs b/crates/ide_db/src/defs.rs
index 0d0affc27..f8c7aa491 100644
--- a/crates/ide_db/src/defs.rs
+++ b/crates/ide_db/src/defs.rs
@@ -157,9 +157,9 @@ pub fn classify_name(sema: &Semantics<RootDatabase>, name: &ast::Name) -> Option
             ast::IdentPat(it) => {
                 let local = sema.to_def(&it)?;
 
-                if let Some(record_field_pat) = it.syntax().parent().and_then(ast::RecordPatField::cast) {
-                    if record_field_pat.name_ref().is_none() {
-                        if let Some(field) = sema.resolve_record_field_pat(&record_field_pat) {
+                if let Some(record_pat_field) = it.syntax().parent().and_then(ast::RecordPatField::cast) {
+                    if record_pat_field.name_ref().is_none() {
+                        if let Some(field) = sema.resolve_record_pat_field(&record_pat_field) {
                             let field = Definition::Field(field);
                             return Some(NameClass::FieldShorthand { local, field });
                         }
@@ -275,8 +275,8 @@ pub fn classify_name_ref(
         }
     }
 
-    if let Some(record_field_pat) = ast::RecordPatField::cast(parent.clone()) {
-        if let Some(field) = sema.resolve_record_field_pat(&record_field_pat) {
+    if let Some(record_pat_field) = ast::RecordPatField::cast(parent.clone()) {
+        if let Some(field) = sema.resolve_record_pat_field(&record_pat_field) {
             let field = Definition::Field(field);
             return Some(NameRefClass::Definition(field));
         }
diff --git a/crates/parser/src/grammar/patterns.rs b/crates/parser/src/grammar/patterns.rs
index 796f206e1..7e7f73dee 100644
--- a/crates/parser/src/grammar/patterns.rs
+++ b/crates/parser/src/grammar/patterns.rs
@@ -188,7 +188,7 @@ fn tuple_pat_fields(p: &mut Parser) {
     p.expect(T![')']);
 }
 
-// test record_field_pat_list
+// test record_pat_field_list
 // fn foo() {
 //     let S {} = ();
 //     let S { f, ref mut g } = ();
@@ -208,7 +208,7 @@ fn record_pat_field_list(p: &mut Parser) {
             c => {
                 let m = p.start();
                 match c {
-                    // test record_field_pat
+                    // test record_pat_field
                     // fn foo() {
                     //     let S { 0: 1 } = ();
                     //     let S { x: 1 } = ();
diff --git a/crates/project_model/src/lib.rs b/crates/project_model/src/lib.rs
index 2d91939ce..288c39e49 100644
--- a/crates/project_model/src/lib.rs
+++ b/crates/project_model/src/lib.rs
@@ -33,7 +33,7 @@ pub enum ProjectWorkspace {
     /// Project workspace was discovered by running `cargo metadata` and `rustc --print sysroot`.
     Cargo { cargo: CargoWorkspace, sysroot: Sysroot },
     /// Project workspace was manually specified using a `rust-project.json` file.
-    Json { project: ProjectJson },
+    Json { project: ProjectJson, sysroot: Option<Sysroot> },
 }
 
 impl fmt::Debug for ProjectWorkspace {
@@ -44,10 +44,10 @@ impl fmt::Debug for ProjectWorkspace {
                 .field("n_packages", &cargo.packages().len())
                 .field("n_sysroot_crates", &sysroot.crates().len())
                 .finish(),
-            ProjectWorkspace::Json { project } => {
+            ProjectWorkspace::Json { project, sysroot } => {
                 let mut debug_struct = f.debug_struct("Json");
                 debug_struct.field("n_crates", &project.n_crates());
-                if let Some(sysroot) = &project.sysroot {
+                if let Some(sysroot) = sysroot {
                     debug_struct.field("n_sysroot_crates", &sysroot.crates().len());
                 }
                 debug_struct.finish()
@@ -169,7 +169,11 @@ impl ProjectWorkspace {
                 })?;
                 let project_location = project_json.parent().unwrap().to_path_buf();
                 let project = ProjectJson::new(&project_location, data);
-                ProjectWorkspace::Json { project }
+                let sysroot = match &project.sysroot_src {
+                    Some(path) => Some(Sysroot::load(path)?),
+                    None => None,
+                };
+                ProjectWorkspace::Json { project, sysroot }
             }
             ProjectManifest::CargoToml(cargo_toml) => {
                 let cargo_version = utf8_stdout({
@@ -203,12 +207,21 @@ impl ProjectWorkspace {
         Ok(res)
     }
 
+    pub fn load_inline(project_json: ProjectJson) -> Result<ProjectWorkspace> {
+        let sysroot = match &project_json.sysroot_src {
+            Some(path) => Some(Sysroot::load(path)?),
+            None => None,
+        };
+
+        Ok(ProjectWorkspace::Json { project: project_json, sysroot })
+    }
+
     /// Returns the roots for the current `ProjectWorkspace`
     /// The return type contains the path and whether or not
     /// the root is a member of the current workspace
     pub fn to_roots(&self) -> Vec<PackageRoot> {
         match self {
-            ProjectWorkspace::Json { project } => project
+            ProjectWorkspace::Json { project, sysroot } => project
                 .crates()
                 .map(|(_, krate)| PackageRoot {
                     is_member: krate.is_workspace_member,
@@ -217,7 +230,7 @@ impl ProjectWorkspace {
                 })
                 .collect::<FxHashSet<_>>()
                 .into_iter()
-                .chain(project.sysroot.as_ref().into_iter().flat_map(|sysroot| {
+                .chain(sysroot.as_ref().into_iter().flat_map(|sysroot| {
                     sysroot.crates().map(move |krate| PackageRoot {
                         is_member: false,
                         include: vec![sysroot[krate].root_dir().to_path_buf()],
@@ -255,7 +268,7 @@ impl ProjectWorkspace {
 
     pub fn proc_macro_dylib_paths(&self) -> Vec<AbsPathBuf> {
         match self {
-            ProjectWorkspace::Json { project } => project
+            ProjectWorkspace::Json { project, sysroot: _ } => project
                 .crates()
                 .filter_map(|(_, krate)| krate.proc_macro_dylib_path.as_ref())
                 .cloned()
@@ -285,9 +298,8 @@ impl ProjectWorkspace {
     ) -> CrateGraph {
         let mut crate_graph = CrateGraph::default();
         match self {
-            ProjectWorkspace::Json { project } => {
-                let sysroot_dps = project
-                    .sysroot
+            ProjectWorkspace::Json { project, sysroot } => {
+                let sysroot_dps = sysroot
                     .as_ref()
                     .map(|sysroot| sysroot_to_crate_graph(&mut crate_graph, sysroot, target, load));
 
diff --git a/crates/project_model/src/project_json.rs b/crates/project_model/src/project_json.rs
index 5a0fe749a..979e90058 100644
--- a/crates/project_model/src/project_json.rs
+++ b/crates/project_model/src/project_json.rs
@@ -7,12 +7,12 @@ use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::FxHashMap;
 use serde::{de, Deserialize};
 
-use crate::{cfg_flag::CfgFlag, Sysroot};
+use crate::cfg_flag::CfgFlag;
 
 /// Roots and crates that compose this Rust project.
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct ProjectJson {
-    pub(crate) sysroot: Option<Sysroot>,
+    pub(crate) sysroot_src: Option<AbsPathBuf>,
     crates: Vec<Crate>,
 }
 
@@ -35,7 +35,7 @@ pub struct Crate {
 impl ProjectJson {
     pub fn new(base: &AbsPath, data: ProjectJsonData) -> ProjectJson {
         ProjectJson {
-            sysroot: data.sysroot_src.map(|it| base.join(it)).map(|it| Sysroot::load(&it)),
+            sysroot_src: data.sysroot_src.map(|it| base.join(it)),
             crates: data
                 .crates
                 .into_iter()
diff --git a/crates/project_model/src/sysroot.rs b/crates/project_model/src/sysroot.rs
index 74c0eda9a..871808d89 100644
--- a/crates/project_model/src/sysroot.rs
+++ b/crates/project_model/src/sysroot.rs
@@ -51,11 +51,11 @@ impl Sysroot {
     pub fn discover(cargo_toml: &AbsPath) -> Result<Sysroot> {
         let current_dir = cargo_toml.parent().unwrap();
         let sysroot_src_dir = discover_sysroot_src_dir(current_dir)?;
-        let res = Sysroot::load(&sysroot_src_dir);
+        let res = Sysroot::load(&sysroot_src_dir)?;
         Ok(res)
     }
 
-    pub fn load(sysroot_src_dir: &AbsPath) -> Sysroot {
+    pub fn load(sysroot_src_dir: &AbsPath) -> Result<Sysroot> {
         let mut sysroot = Sysroot { crates: Arena::default() };
 
         for name in SYSROOT_CRATES.trim().lines() {
@@ -89,7 +89,14 @@ impl Sysroot {
             }
         }
 
-        sysroot
+        if sysroot.by_name("core").is_none() {
+            anyhow::bail!(
+                "could not find libcore in sysroot path `{}`",
+                sysroot_src_dir.as_ref().display()
+            );
+        }
+
+        Ok(sysroot)
     }
 
     fn by_name(&self, name: &str) -> Option<SysrootCrate> {
diff --git a/crates/rust-analyzer/src/diagnostics/test_data/macro_compiler_error.txt b/crates/rust-analyzer/src/diagnostics/test_data/macro_compiler_error.txt
index 89dae7d5a..00e8da8a7 100644
--- a/crates/rust-analyzer/src/diagnostics/test_data/macro_compiler_error.txt
+++ b/crates/rust-analyzer/src/diagnostics/test_data/macro_compiler_error.txt
@@ -44,4 +44,49 @@
         },
         fixes: [],
     },
+    MappedRustDiagnostic {
+        url: "file:///test/crates/hir_def/src/path.rs",
+        diagnostic: Diagnostic {
+            range: Range {
+                start: Position {
+                    line: 264,
+                    character: 8,
+                },
+                end: Position {
+                    line: 264,
+                    character: 76,
+                },
+            },
+            severity: Some(
+                Error,
+            ),
+            code: None,
+            source: Some(
+                "rustc",
+            ),
+            message: "Please register your known path in the path module",
+            related_information: Some(
+                [
+                    DiagnosticRelatedInformation {
+                        location: Location {
+                            uri: "file:///test/crates/hir_def/src/data.rs",
+                            range: Range {
+                                start: Position {
+                                    line: 79,
+                                    character: 15,
+                                },
+                                end: Position {
+                                    line: 79,
+                                    character: 41,
+                                },
+                            },
+                        },
+                        message: "Exact error occured here",
+                    },
+                ],
+            ),
+            tags: None,
+        },
+        fixes: [],
+    },
 ]
diff --git a/crates/rust-analyzer/src/diagnostics/to_proto.rs b/crates/rust-analyzer/src/diagnostics/to_proto.rs
index f69a949f2..33606edda 100644
--- a/crates/rust-analyzer/src/diagnostics/to_proto.rs
+++ b/crates/rust-analyzer/src/diagnostics/to_proto.rs
@@ -225,12 +225,43 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
 
             // If error occurs from macro expansion, add related info pointing to
             // where the error originated
-            if !is_from_macro(&primary_span.file_name) && primary_span.expansion.is_some() {
-                related_information.push(lsp_types::DiagnosticRelatedInformation {
-                    location: location_naive(workspace_root, &primary_span),
-                    message: "Error originated from macro here".to_string(),
-                });
-            }
+            // Also, we would generate an additional diagnostic, so that exact place of macro
+            // will be highlighted in the error origin place.
+            let additional_diagnostic =
+                if !is_from_macro(&primary_span.file_name) && primary_span.expansion.is_some() {
+                    let in_macro_location = location_naive(workspace_root, &primary_span);
+
+                    // Add related information for the main disagnostic.
+                    related_information.push(lsp_types::DiagnosticRelatedInformation {
+                        location: in_macro_location.clone(),
+                        message: "Error originated from macro here".to_string(),
+                    });
+
+                    // For the additional in-macro diagnostic we add the inverse message pointing to the error location in code.
+                    let information_for_additional_diagnostic =
+                        vec![lsp_types::DiagnosticRelatedInformation {
+                            location: location.clone(),
+                            message: "Exact error occured here".to_string(),
+                        }];
+
+                    let diagnostic = lsp_types::Diagnostic {
+                        range: in_macro_location.range,
+                        severity,
+                        code: code.clone().map(lsp_types::NumberOrString::String),
+                        source: Some(source.clone()),
+                        message: message.clone(),
+                        related_information: Some(information_for_additional_diagnostic),
+                        tags: if tags.is_empty() { None } else { Some(tags.clone()) },
+                    };
+
+                    Some(MappedRustDiagnostic {
+                        url: in_macro_location.uri,
+                        diagnostic,
+                        fixes: fixes.clone(),
+                    })
+                } else {
+                    None
+                };
 
             let diagnostic = lsp_types::Diagnostic {
                 range: location.range,
@@ -246,8 +277,14 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
                 tags: if tags.is_empty() { None } else { Some(tags.clone()) },
             };
 
-            MappedRustDiagnostic { url: location.uri, diagnostic, fixes: fixes.clone() }
+            let main_diagnostic =
+                MappedRustDiagnostic { url: location.uri, diagnostic, fixes: fixes.clone() };
+            match additional_diagnostic {
+                None => vec![main_diagnostic],
+                Some(additional_diagnostic) => vec![main_diagnostic, additional_diagnostic],
+            }
         })
+        .flatten()
         .collect()
 }
 
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index 20019b944..bab6f8a71 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -109,7 +109,7 @@ impl GlobalState {
                             )
                         }
                         LinkedProject::InlineJsonProject(it) => {
-                            Ok(project_model::ProjectWorkspace::Json { project: it.clone() })
+                            project_model::ProjectWorkspace::load_inline(it.clone())
                         }
                     })
                     .collect::<Vec<_>>();
diff --git a/crates/syntax/test_data/parser/inline/ok/0102_record_field_pat_list.rast b/crates/syntax/test_data/parser/inline/ok/0102_record_pat_field_list.rast
index 866e60ed8..866e60ed8 100644
--- a/crates/syntax/test_data/parser/inline/ok/0102_record_field_pat_list.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0102_record_pat_field_list.rast
diff --git a/crates/syntax/test_data/parser/inline/ok/0102_record_field_pat_list.rs b/crates/syntax/test_data/parser/inline/ok/0102_record_pat_field_list.rs
index da3412fa8..da3412fa8 100644
--- a/crates/syntax/test_data/parser/inline/ok/0102_record_field_pat_list.rs
+++ b/crates/syntax/test_data/parser/inline/ok/0102_record_pat_field_list.rs
diff --git a/crates/syntax/test_data/parser/inline/ok/0145_record_field_pat.rast b/crates/syntax/test_data/parser/inline/ok/0145_record_pat_field.rast
index 925409bdf..925409bdf 100644
--- a/crates/syntax/test_data/parser/inline/ok/0145_record_field_pat.rast
+++ b/crates/syntax/test_data/parser/inline/ok/0145_record_pat_field.rast
diff --git a/crates/syntax/test_data/parser/inline/ok/0145_record_field_pat.rs b/crates/syntax/test_data/parser/inline/ok/0145_record_pat_field.rs
index 26b1d5f89..26b1d5f89 100644
--- a/crates/syntax/test_data/parser/inline/ok/0145_record_field_pat.rs
+++ b/crates/syntax/test_data/parser/inline/ok/0145_record_pat_field.rs
diff --git a/crates/vfs/src/file_set.rs b/crates/vfs/src/file_set.rs
index e9196fcd2..4aa2d6526 100644
--- a/crates/vfs/src/file_set.rs
+++ b/crates/vfs/src/file_set.rs
@@ -23,13 +23,22 @@ impl FileSet {
         let mut base = self.paths[&anchor].clone();
         base.pop();
         let path = base.join(path)?;
-        let res = self.files.get(&path).copied();
-        res
+        self.files.get(&path).copied()
+    }
+
+    pub fn file_for_path(&self, path: &VfsPath) -> Option<&FileId> {
+        self.files.get(path)
     }
+
+    pub fn path_for_file(&self, file: &FileId) -> Option<&VfsPath> {
+        self.paths.get(file)
+    }
+
     pub fn insert(&mut self, file_id: FileId, path: VfsPath) {
         self.files.insert(path.clone(), file_id);
         self.paths.insert(file_id, path);
     }
+
     pub fn iter(&self) -> impl Iterator<Item = FileId> + '_ {
         self.paths.keys().copied()
     }
diff --git a/crates/vfs/src/vfs_path.rs b/crates/vfs/src/vfs_path.rs
index 944a702df..022a0be1e 100644
--- a/crates/vfs/src/vfs_path.rs
+++ b/crates/vfs/src/vfs_path.rs
@@ -48,6 +48,24 @@ impl VfsPath {
             (VfsPathRepr::VirtualPath(_), _) => false,
         }
     }
+    pub fn parent(&self) -> Option<VfsPath> {
+        let mut parent = self.clone();
+        if parent.pop() {
+            Some(parent)
+        } else {
+            None
+        }
+    }
+
+    pub fn name_and_extension(&self) -> Option<(&str, Option<&str>)> {
+        match &self.0 {
+            VfsPathRepr::PathBuf(p) => Some((
+                p.file_stem()?.to_str()?,
+                p.extension().and_then(|extension| extension.to_str()),
+            )),
+            VfsPathRepr::VirtualPath(p) => p.name_and_extension(),
+        }
+    }
 
     // Don't make this `pub`
     pub(crate) fn encode(&self, buf: &mut Vec<u8>) {
@@ -268,4 +286,60 @@ impl VirtualPath {
         res.0 = format!("{}/{}", res.0, path);
         Some(res)
     }
+
+    pub fn name_and_extension(&self) -> Option<(&str, Option<&str>)> {
+        let file_path = if self.0.ends_with('/') { &self.0[..&self.0.len() - 1] } else { &self.0 };
+        let file_name = match file_path.rfind('/') {
+            Some(position) => &file_path[position + 1..],
+            None => file_path,
+        };
+
+        if file_name.is_empty() {
+            None
+        } else {
+            let mut file_stem_and_extension = file_name.rsplitn(2, '.');
+            let extension = file_stem_and_extension.next();
+            let file_stem = file_stem_and_extension.next();
+
+            match (file_stem, extension) {
+                (None, None) => None,
+                (None, Some(_)) | (Some(""), Some(_)) => Some((file_name, None)),
+                (Some(file_stem), extension) => Some((file_stem, extension)),
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn virtual_path_extensions() {
+        assert_eq!(VirtualPath("/".to_string()).name_and_extension(), None);
+        assert_eq!(
+            VirtualPath("/directory".to_string()).name_and_extension(),
+            Some(("directory", None))
+        );
+        assert_eq!(
+            VirtualPath("/directory/".to_string()).name_and_extension(),
+            Some(("directory", None))
+        );
+        assert_eq!(
+            VirtualPath("/directory/file".to_string()).name_and_extension(),
+            Some(("file", None))
+        );
+        assert_eq!(
+            VirtualPath("/directory/.file".to_string()).name_and_extension(),
+            Some((".file", None))
+        );
+        assert_eq!(
+            VirtualPath("/directory/.file.rs".to_string()).name_and_extension(),
+            Some((".file", Some("rs")))
+        );
+        assert_eq!(
+            VirtualPath("/directory/file.rs".to_string()).name_and_extension(),
+            Some(("file", Some("rs")))
+        );
+    }
 }