6 files changed, 72 insertions, 19 deletions

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;