13 files changed, 247 insertions, 113 deletions

diff --git a/Cargo.lock b/Cargo.lock
index ca0311595..bcb1cbd9f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -797,9 +797,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.92"
+version = "0.2.93"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "56d855069fafbb9b344c0f962150cd2c1187975cb1c22c1522c240d8c4986714"
+checksum = "9385f66bf6105b241aa65a61cb923ef20efc665cb9f9bb50ac2f0c4b7f378d41"
 
 [[package]]
 name = "libloading"
@@ -912,9 +912,9 @@ dependencies = [
 
 [[package]]
 name = "memmap2"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "04e3e85b970d650e2ae6d70592474087051c11c54da7f7b4949725c5735fbcc6"
+checksum = "397d1a6d6d0563c0f5462bbdae662cf6c784edf5e828e40c7257f85d82bf56dd"
 dependencies = [
  "libc",
 ]
@@ -1391,9 +1391,9 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-rustc_lexer"
-version = "710.0.0"
+version = "714.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b0bba1ca6787b6d4af505b7a940eae9ecb084dd03e07f03bf3ddbf78e738b617"
+checksum = "a35856f140bed0dc7c7d6ba2134099d337377a3a4e11bfc79bccabf1fd4c9d42"
 dependencies = [
  "unicode-xid",
 ]
@@ -1675,9 +1675,9 @@ dependencies = [
 
 [[package]]
 name = "tinyvec"
-version = "1.1.1"
+version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "317cca572a0e89c3ce0ca1f1bdc9369547fe318a683418e42ac8f59d14701023"
+checksum = "5b5220f05bb7de7f3f53c7c065e1199b3172696fe2db9f9c4d8ad9b4ee74c342"
 dependencies = [
  "tinyvec_macros",
 ]
@@ -1815,9 +1815,9 @@ dependencies = [
 
 [[package]]
 name = "unicode-bidi"
-version = "0.3.4"
+version = "0.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
+checksum = "eeb8be209bb1c96b7c177c7420d26e04eccacb0eeae6b980e35fcb74678107e0"
 dependencies = [
  "matches",
 ]
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 86b36c565..13aaa408a 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -1972,9 +1972,9 @@ impl Type {
     pub fn type_parameters(&self) -> impl Iterator<Item = Type> + '_ {
         self.ty
             .strip_references()
-            .substs()
+            .as_adt()
             .into_iter()
-            .flat_map(|substs| substs.iter(&Interner))
+            .flat_map(|(_, substs)| substs.iter(&Interner))
             .filter_map(|arg| arg.ty(&Interner).cloned())
             .map(move |ty| self.derived(ty))
     }
@@ -2115,18 +2115,22 @@ impl Type {
         fn walk_type(db: &dyn HirDatabase, type_: &Type, cb: &mut impl FnMut(Type)) {
             let ty = type_.ty.strip_references();
             match ty.kind(&Interner) {
-                TyKind::Adt(..) => {
+                TyKind::Adt(_, substs) => {
                     cb(type_.derived(ty.clone()));
+                    walk_substs(db, type_, &substs, cb);
                 }
-                TyKind::AssociatedType(..) => {
+                TyKind::AssociatedType(_, substs) => {
                     if let Some(_) = ty.associated_type_parent_trait(db) {
                         cb(type_.derived(ty.clone()));
                     }
+                    walk_substs(db, type_, &substs, cb);
                 }
-                TyKind::OpaqueType(..) => {
+                TyKind::OpaqueType(_, subst) => {
                     if let Some(bounds) = ty.impl_trait_bounds(db) {
                         walk_bounds(db, &type_.derived(ty.clone()), &bounds, cb);
                     }
+
+                    walk_substs(db, type_, subst, cb);
                 }
                 TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
                     if let Some(bounds) = ty.impl_trait_bounds(db) {
@@ -2156,11 +2160,17 @@ impl Type {
                     walk_type(db, &type_.derived(ty.clone()), cb);
                 }
 
+                TyKind::FnDef(_, substs)
+                | TyKind::Tuple(_, substs)
+                | TyKind::Closure(.., substs) => {
+                    walk_substs(db, type_, &substs, cb);
+                }
+                TyKind::Function(hir_ty::FnPointer { substitution, .. }) => {
+                    walk_substs(db, type_, &substitution.0, cb);
+                }
+
                 _ => {}
             }
-            if let Some(substs) = ty.substs() {
-                walk_substs(db, type_, &substs, cb);
-            }
         }
 
         walk_type(db, self, &mut cb);
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index ce6f3c008..847d2537d 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -20,7 +20,7 @@ use hir_def::{
 use hir_expand::{hygiene::Hygiene, name::AsName, HirFileId, InFile};
 use hir_ty::{
     diagnostics::{record_literal_missing_fields, record_pattern_missing_fields},
-    InferenceResult, Interner, Substitution, TyLoweringContext,
+    InferenceResult, Interner, Substitution, TyExt, TyLoweringContext,
 };
 use syntax::{
     ast::{self, AstNode},
@@ -306,7 +306,7 @@ impl SourceAnalyzer {
         let infer = self.infer.as_ref()?;
 
         let expr_id = self.expr_id(db, &literal.clone().into())?;
-        let substs = infer.type_of_expr[expr_id].substs()?;
+        let substs = infer.type_of_expr[expr_id].as_adt()?.1;
 
         let (variant, missing_fields, _exhaustive) =
             record_literal_missing_fields(db, infer, expr_id, &body[expr_id])?;
@@ -324,7 +324,7 @@ impl SourceAnalyzer {
         let infer = self.infer.as_ref()?;
 
         let pat_id = self.pat_id(&pattern.clone().into())?;
-        let substs = infer.type_of_pat[pat_id].substs()?;
+        let substs = infer.type_of_pat[pat_id].as_adt()?.1;
 
         let (variant, missing_fields, _exhaustive) =
             record_pattern_missing_fields(db, infer, pat_id, &body[pat_id])?;
diff --git a/crates/hir_ty/src/chalk_ext.rs b/crates/hir_ty/src/chalk_ext.rs
index 8e8a1aa48..6a353423a 100644
--- a/crates/hir_ty/src/chalk_ext.rs
+++ b/crates/hir_ty/src/chalk_ext.rs
@@ -8,7 +8,7 @@ use hir_def::{
 use crate::{
     db::HirDatabase, from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id,
     from_placeholder_idx, to_chalk_trait_id, AdtId, AliasEq, AliasTy, Binders, CallableDefId,
-    CallableSig, ImplTraitId, Interner, Lifetime, ProjectionTy, QuantifiedWhereClause,
+    CallableSig, FnPointer, ImplTraitId, Interner, Lifetime, ProjectionTy, QuantifiedWhereClause,
     Substitution, TraitRef, Ty, TyBuilder, TyKind, WhereClause,
 };
 
@@ -34,6 +34,9 @@ pub trait TyExt {
 
     fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>>;
     fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId>;
+
+    /// FIXME: Get rid of this, it's not a good abstraction
+    fn equals_ctor(&self, other: &Ty) -> bool;
 }
 
 impl TyExt for Ty {
@@ -238,6 +241,36 @@ impl TyExt for Ty {
             _ => None,
         }
     }
+
+    fn equals_ctor(&self, other: &Ty) -> bool {
+        match (self.kind(&Interner), other.kind(&Interner)) {
+            (TyKind::Adt(adt, ..), TyKind::Adt(adt2, ..)) => adt == adt2,
+            (TyKind::Slice(_), TyKind::Slice(_)) | (TyKind::Array(_, _), TyKind::Array(_, _)) => {
+                true
+            }
+            (TyKind::FnDef(def_id, ..), TyKind::FnDef(def_id2, ..)) => def_id == def_id2,
+            (TyKind::OpaqueType(ty_id, ..), TyKind::OpaqueType(ty_id2, ..)) => ty_id == ty_id2,
+            (TyKind::AssociatedType(ty_id, ..), TyKind::AssociatedType(ty_id2, ..)) => {
+                ty_id == ty_id2
+            }
+            (TyKind::Foreign(ty_id, ..), TyKind::Foreign(ty_id2, ..)) => ty_id == ty_id2,
+            (TyKind::Closure(id1, _), TyKind::Closure(id2, _)) => id1 == id2,
+            (TyKind::Ref(mutability, ..), TyKind::Ref(mutability2, ..))
+            | (TyKind::Raw(mutability, ..), TyKind::Raw(mutability2, ..)) => {
+                mutability == mutability2
+            }
+            (
+                TyKind::Function(FnPointer { num_binders, sig, .. }),
+                TyKind::Function(FnPointer { num_binders: num_binders2, sig: sig2, .. }),
+            ) => num_binders == num_binders2 && sig == sig2,
+            (TyKind::Tuple(cardinality, _), TyKind::Tuple(cardinality2, _)) => {
+                cardinality == cardinality2
+            }
+            (TyKind::Str, TyKind::Str) | (TyKind::Never, TyKind::Never) => true,
+            (TyKind::Scalar(scalar), TyKind::Scalar(scalar2)) => scalar == scalar2,
+            _ => false,
+        }
+    }
 }
 
 pub trait ProjectionTyExt {
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 9ab0fa212..9841988c5 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -412,7 +412,10 @@ impl<'a> InferenceContext<'a> {
 
                 self.unify(&ty, &expected.ty);
 
-                let substs = ty.substs().cloned().unwrap_or_else(|| Substitution::empty(&Interner));
+                let substs = ty
+                    .as_adt()
+                    .map(|(_, s)| s.clone())
+                    .unwrap_or_else(|| Substitution::empty(&Interner));
                 let field_types = def_id.map(|it| self.db.field_types(it)).unwrap_or_default();
                 let variant_data = def_id.map(|it| it.variant_data(self.db.upcast()));
                 for field in fields.iter() {
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index e4813c87c..f88d5c5d3 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -33,7 +33,8 @@ impl<'a> InferenceContext<'a> {
         }
         self.unify(&ty, expected);
 
-        let substs = ty.substs().cloned().unwrap_or_else(|| Substitution::empty(&Interner));
+        let substs =
+            ty.as_adt().map(|(_, s)| s.clone()).unwrap_or_else(|| Substitution::empty(&Interner));
 
         let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default();
         let (pre, post) = match ellipsis {
@@ -74,7 +75,8 @@ impl<'a> InferenceContext<'a> {
 
         self.unify(&ty, expected);
 
-        let substs = ty.substs().cloned().unwrap_or_else(|| Substitution::empty(&Interner));
+        let substs =
+            ty.as_adt().map(|(_, s)| s.clone()).unwrap_or_else(|| Substitution::empty(&Interner));
 
         let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default();
         for subpat in subpats {
diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs
index d717e3375..2ea9dd920 100644
--- a/crates/hir_ty/src/infer/unify.rs
+++ b/crates/hir_ty/src/infer/unify.rs
@@ -8,7 +8,8 @@ use ena::unify::{InPlaceUnificationTable, NoError, UnifyKey, UnifyValue};
 use super::{DomainGoal, InferenceContext};
 use crate::{
     AliasEq, AliasTy, BoundVar, Canonical, CanonicalVarKinds, DebruijnIndex, FnPointer, FnSubst,
-    InEnvironment, InferenceVar, Interner, Scalar, Substitution, Ty, TyKind, TypeWalk, WhereClause,
+    InEnvironment, InferenceVar, Interner, Scalar, Substitution, Ty, TyExt, TyKind, TypeWalk,
+    WhereClause,
 };
 
 impl<'a> InferenceContext<'a> {
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index ae3987752..2e851d3e0 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -168,65 +168,7 @@ impl CallableSig {
     }
 }
 
-impl Ty {
-    pub fn equals_ctor(&self, other: &Ty) -> bool {
-        match (self.kind(&Interner), other.kind(&Interner)) {
-            (TyKind::Adt(adt, ..), TyKind::Adt(adt2, ..)) => adt == adt2,
-            (TyKind::Slice(_), TyKind::Slice(_)) | (TyKind::Array(_, _), TyKind::Array(_, _)) => {
-                true
-            }
-            (TyKind::FnDef(def_id, ..), TyKind::FnDef(def_id2, ..)) => def_id == def_id2,
-            (TyKind::OpaqueType(ty_id, ..), TyKind::OpaqueType(ty_id2, ..)) => ty_id == ty_id2,
-            (TyKind::AssociatedType(ty_id, ..), TyKind::AssociatedType(ty_id2, ..)) => {
-                ty_id == ty_id2
-            }
-            (TyKind::Foreign(ty_id, ..), TyKind::Foreign(ty_id2, ..)) => ty_id == ty_id2,
-            (TyKind::Closure(id1, _), TyKind::Closure(id2, _)) => id1 == id2,
-            (TyKind::Ref(mutability, ..), TyKind::Ref(mutability2, ..))
-            | (TyKind::Raw(mutability, ..), TyKind::Raw(mutability2, ..)) => {
-                mutability == mutability2
-            }
-            (
-                TyKind::Function(FnPointer { num_binders, sig, .. }),
-                TyKind::Function(FnPointer { num_binders: num_binders2, sig: sig2, .. }),
-            ) => num_binders == num_binders2 && sig == sig2,
-            (TyKind::Tuple(cardinality, _), TyKind::Tuple(cardinality2, _)) => {
-                cardinality == cardinality2
-            }
-            (TyKind::Str, TyKind::Str) | (TyKind::Never, TyKind::Never) => true,
-            (TyKind::Scalar(scalar), TyKind::Scalar(scalar2)) => scalar == scalar2,
-            _ => false,
-        }
-    }
-
-    /// Returns the type parameters of this type if it has some (i.e. is an ADT
-    /// or function); so if `self` is `Option<u32>`, this returns the `u32`.
-    pub fn substs(&self) -> Option<&Substitution> {
-        match self.kind(&Interner) {
-            TyKind::Adt(_, substs)
-            | TyKind::FnDef(_, substs)
-            | TyKind::Tuple(_, substs)
-            | TyKind::OpaqueType(_, substs)
-            | TyKind::AssociatedType(_, substs)
-            | TyKind::Closure(.., substs) => Some(substs),
-            TyKind::Function(FnPointer { substitution: substs, .. }) => Some(&substs.0),
-            _ => None,
-        }
-    }
-
-    fn substs_mut(&mut self) -> Option<&mut Substitution> {
-        match self.interned_mut() {
-            TyKind::Adt(_, substs)
-            | TyKind::FnDef(_, substs)
-            | TyKind::Tuple(_, substs)
-            | TyKind::OpaqueType(_, substs)
-            | TyKind::AssociatedType(_, substs)
-            | TyKind::Closure(.., substs) => Some(substs),
-            TyKind::Function(FnPointer { substitution: substs, .. }) => Some(&mut substs.0),
-            _ => None,
-        }
-    }
-}
+impl Ty {}
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
 pub enum ImplTraitId {
diff --git a/crates/hir_ty/src/walk.rs b/crates/hir_ty/src/walk.rs
index 41ebf6137..91116dcda 100644
--- a/crates/hir_ty/src/walk.rs
+++ b/crates/hir_ty/src/walk.rs
@@ -162,13 +162,15 @@ impl TypeWalk for Ty {
             TyKind::Function(fn_pointer) => {
                 fn_pointer.substitution.0.walk(f);
             }
-            _ => {
-                if let Some(substs) = self.substs() {
-                    for t in substs.iter(&Interner) {
-                        t.walk(f);
-                    }
-                }
+            TyKind::Adt(_, substs)
+            | TyKind::FnDef(_, substs)
+            | TyKind::Tuple(_, substs)
+            | TyKind::OpaqueType(_, substs)
+            | TyKind::AssociatedType(_, substs)
+            | TyKind::Closure(.., substs) => {
+                substs.walk(f);
             }
+            _ => {}
         }
         f(self);
     }
@@ -199,11 +201,15 @@ impl TypeWalk for Ty {
             TyKind::Function(fn_pointer) => {
                 fn_pointer.substitution.0.walk_mut_binders(f, binders.shifted_in());
             }
-            _ => {
-                if let Some(substs) = self.substs_mut() {
-                    substs.walk_mut_binders(f, binders);
-                }
+            TyKind::Adt(_, substs)
+            | TyKind::FnDef(_, substs)
+            | TyKind::Tuple(_, substs)
+            | TyKind::OpaqueType(_, substs)
+            | TyKind::AssociatedType(_, substs)
+            | TyKind::Closure(.., substs) => {
+                substs.walk_mut_binders(f, binders);
             }
+            _ => {}
         }
         f(self, binders);
     }
diff --git a/crates/ide/src/typing.rs b/crates/ide/src/typing.rs
index 11408d445..1378048e5 100644
--- a/crates/ide/src/typing.rs
+++ b/crates/ide/src/typing.rs
@@ -22,18 +22,19 @@ use ide_db::{
 use syntax::{
     algo::find_node_at_offset,
     ast::{self, edit::IndentLevel, AstToken},
-    AstNode, SourceFile,
+    AstNode, Parse, SourceFile,
     SyntaxKind::{FIELD_EXPR, METHOD_CALL_EXPR},
     TextRange, TextSize,
 };
 
-use text_edit::TextEdit;
+use text_edit::{Indel, TextEdit};
 
 use crate::SourceChange;
 
 pub(crate) use on_enter::on_enter;
 
-pub(crate) const TRIGGER_CHARS: &str = ".=>";
+// Don't forget to add new trigger characters to `server_capabilities` in `caps.rs`.
+pub(crate) const TRIGGER_CHARS: &str = ".=>{";
 
 // Feature: On Typing Assists
 //
@@ -41,6 +42,7 @@ pub(crate) const TRIGGER_CHARS: &str = ".=>";
 //
 // - typing `let =` tries to smartly add `;` if `=` is followed by an existing expression
 // - typing `.` in a chain method call auto-indents
+// - typing `{` in front of an expression inserts a closing `}` after the expression
 //
 // VS Code::
 //
@@ -57,28 +59,79 @@ pub(crate) fn on_char_typed(
     position: FilePosition,
     char_typed: char,
 ) -> Option<SourceChange> {
-    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));
+    if !stdx::always!(TRIGGER_CHARS.contains(char_typed)) {
+        return None;
+    }
+    let file = &db.parse(position.file_id);
+    if !stdx::always!(file.tree().syntax().text().char_at(position.offset) == Some(char_typed)) {
+        return None;
+    }
     let edit = on_char_typed_inner(file, position.offset, char_typed)?;
     Some(SourceChange::from_text_edit(position.file_id, edit))
 }
 
-fn on_char_typed_inner(file: &SourceFile, offset: TextSize, char_typed: char) -> Option<TextEdit> {
-    assert!(TRIGGER_CHARS.contains(char_typed));
+fn on_char_typed_inner(
+    file: &Parse<SourceFile>,
+    offset: TextSize,
+    char_typed: char,
+) -> Option<TextEdit> {
+    if !stdx::always!(TRIGGER_CHARS.contains(char_typed)) {
+        return None;
+    }
     match char_typed {
-        '.' => on_dot_typed(file, offset),
-        '=' => on_eq_typed(file, offset),
-        '>' => on_arrow_typed(file, offset),
+        '.' => on_dot_typed(&file.tree(), offset),
+        '=' => on_eq_typed(&file.tree(), offset),
+        '>' => on_arrow_typed(&file.tree(), offset),
+        '{' => on_opening_brace_typed(file, offset),
         _ => unreachable!(),
     }
 }
 
+/// Inserts a closing `}` when the user types an opening `{`, wrapping an existing expression in a
+/// block.
+fn on_opening_brace_typed(file: &Parse<SourceFile>, offset: TextSize) -> Option<TextEdit> {
+    if !stdx::always!(file.tree().syntax().text().char_at(offset) == Some('{')) {
+        return None;
+    }
+
+    let brace_token = file.tree().syntax().token_at_offset(offset).right_biased()?;
+
+    // Remove the `{` to get a better parse tree, and reparse
+    let file = file.reparse(&Indel::delete(brace_token.text_range()));
+
+    let mut expr: ast::Expr = find_node_at_offset(file.tree().syntax(), offset)?;
+    if expr.syntax().text_range().start() != offset {
+        return None;
+    }
+
+    // Enclose the outermost expression starting at `offset`
+    while let Some(parent) = expr.syntax().parent() {
+        if parent.text_range().start() != expr.syntax().text_range().start() {
+            break;
+        }
+
+        match ast::Expr::cast(parent) {
+            Some(parent) => expr = parent,
+            None => break,
+        }
+    }
+
+    // If it's a statement in a block, we don't know how many statements should be included
+    if ast::ExprStmt::can_cast(expr.syntax().parent()?.kind()) {
+        return None;
+    }
+
+    // Insert `}` right after the expression.
+    Some(TextEdit::insert(expr.syntax().text_range().end() + TextSize::of("{"), "}".to_string()))
+}
+
 /// 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<TextEdit> {
-    assert_eq!(file.syntax().text().char_at(offset), Some('='));
+    if !stdx::always!(file.syntax().text().char_at(offset) == Some('=')) {
+        return None;
+    }
     let let_stmt: ast::LetStmt = find_node_at_offset(file.syntax(), offset)?;
     if let_stmt.semicolon_token().is_some() {
         return None;
@@ -100,7 +153,9 @@ fn on_eq_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
 
 /// 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<TextEdit> {
-    assert_eq!(file.syntax().text().char_at(offset), Some('.'));
+    if !stdx::always!(file.syntax().text().char_at(offset) == Some('.')) {
+        return None;
+    }
     let whitespace =
         file.syntax().token_at_offset(offset).left_biased().and_then(ast::Whitespace::cast)?;
 
@@ -129,7 +184,9 @@ fn on_dot_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
 /// Adds a space after an arrow when `fn foo() { ... }` is turned into `fn foo() -> { ... }`
 fn on_arrow_typed(file: &SourceFile, offset: TextSize) -> Option<TextEdit> {
     let file_text = file.syntax().text();
-    assert_eq!(file_text.char_at(offset), Some('>'));
+    if !stdx::always!(file_text.char_at(offset) == Some('>')) {
+        return None;
+    }
     let after_arrow = offset + TextSize::of('>');
     if file_text.char_at(after_arrow) != Some('{') {
         return None;
@@ -152,7 +209,7 @@ mod tests {
         let edit = TextEdit::insert(offset, char_typed.to_string());
         edit.apply(&mut before);
         let parse = SourceFile::parse(&before);
-        on_char_typed_inner(&parse.tree(), offset, char_typed).map(|it| {
+        on_char_typed_inner(&parse, offset, char_typed).map(|it| {
             it.apply(&mut before);
             before.to_string()
         })
@@ -373,4 +430,85 @@ fn main() {
     fn adds_space_after_return_type() {
         type_char('>', "fn foo() -$0{ 92 }", "fn foo() -> { 92 }")
     }
+
+    #[test]
+    fn adds_closing_brace() {
+        type_char(
+            '{',
+            r#"
+fn f() { match () { _ => $0() } }
+            "#,
+            r#"
+fn f() { match () { _ => {()} } }
+            "#,
+        );
+        type_char(
+            '{',
+            r#"
+fn f() { $0() }
+            "#,
+            r#"
+fn f() { {()} }
+            "#,
+        );
+        type_char(
+            '{',
+            r#"
+fn f() { let x = $0(); }
+            "#,
+            r#"
+fn f() { let x = {()}; }
+            "#,
+        );
+        type_char(
+            '{',
+            r#"
+fn f() { let x = $0a.b(); }
+            "#,
+            r#"
+fn f() { let x = {a.b()}; }
+            "#,
+        );
+        type_char(
+            '{',
+            r#"
+const S: () = $0();
+fn f() {}
+            "#,
+            r#"
+const S: () = {()};
+fn f() {}
+            "#,
+        );
+        type_char(
+            '{',
+            r#"
+const S: () = $0a.b();
+fn f() {}
+            "#,
+            r#"
+const S: () = {a.b()};
+fn f() {}
+            "#,
+        );
+        type_char(
+            '{',
+            r#"
+fn f() {
+    match x {
+        0 => $0(),
+        1 => (),
+    }
+}
+            "#,
+            r#"
+fn f() {
+    match x {
+        0 => {()},
+        1 => (),
+    }
+}
+            "#,
+        );
+    }
 }
diff --git a/crates/rust-analyzer/src/caps.rs b/crates/rust-analyzer/src/caps.rs
index 7a5bcb8c7..3c87782f2 100644
--- a/crates/rust-analyzer/src/caps.rs
+++ b/crates/rust-analyzer/src/caps.rs
@@ -57,7 +57,7 @@ pub fn server_capabilities(client_caps: &ClientCapabilities) -> ServerCapabiliti
         document_range_formatting_provider: None,
         document_on_type_formatting_provider: Some(DocumentOnTypeFormattingOptions {
             first_trigger_character: "=".to_string(),
-            more_trigger_character: Some(vec![".".to_string(), ">".to_string()]),
+            more_trigger_character: Some(vec![".".to_string(), ">".to_string(), "{".to_string()]),
         }),
         selection_range_provider: Some(SelectionRangeProviderCapability::Simple(true)),
         folding_range_provider: Some(FoldingRangeProviderCapability::Simple(true)),
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index 4d10a2ead..31d8c487b 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -231,7 +231,6 @@ pub(crate) fn handle_on_enter(
     Ok(Some(edit))
 }
 
-// Don't forget to add new trigger characters to `ServerCapabilities` in `caps.rs`.
 pub(crate) fn handle_on_type_formatting(
     snap: GlobalStateSnapshot,
     params: lsp_types::DocumentOnTypeFormattingParams,
diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index 10024366e..f09cdf28a 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -14,7 +14,7 @@ doctest = false
 cov-mark = { version = "1.1", features = ["thread-local"] }
 itertools = "0.10.0"
 rowan = "0.13.0-pre.3"
-rustc_lexer = { version = "710.0.0", package = "rustc-ap-rustc_lexer" }
+rustc_lexer = { version = "714.0.0", package = "rustc-ap-rustc_lexer" }
 rustc-hash = "1.1.0"
 arrayvec = "0.7"
 once_cell = "1.3.1"