6 files changed, 54 insertions, 30 deletions

diff --git a/crates/ra_hir/src/code_model_impl/function/scope.rs b/crates/ra_hir/src/code_model_impl/function/scope.rs
index 7e8eb7704..220c71f74 100644
--- a/crates/ra_hir/src/code_model_impl/function/scope.rs
+++ b/crates/ra_hir/src/code_model_impl/function/scope.rs
@@ -88,10 +88,17 @@ impl FnScopes {
 
     fn add_bindings(&mut self, body: &Body, scope: ScopeId, pat: PatId) {
         match &body[pat] {
-            Pat::Bind { name, .. } => self.scopes[scope].entries.push(ScopeEntry {
-                name: name.clone(),
-                pat,
-            }),
+            Pat::Bind { name, .. } => {
+                // bind can have a subpattern, but it's actually not allowed
+                // to bind to things in there
+                let entry = ScopeEntry {
+                    name: name.clone(),
+                    pat,
+                };
+                self.scopes[scope].entries.push(entry)
+            }
+            // FIXME: isn't every call to add_binding starting an entirely new
+            // tree walk!?
             p => p.walk_child_pats(|pat| self.add_bindings(body, scope, pat)),
         }
     }
diff --git a/crates/ra_hir/src/expr.rs b/crates/ra_hir/src/expr.rs
index 4d372c97b..c05bbc442 100644
--- a/crates/ra_hir/src/expr.rs
+++ b/crates/ra_hir/src/expr.rs
@@ -398,7 +398,7 @@ pub enum Pat {
     Bind {
         mode: BindingAnnotation,
         name: Name,
-        sub_pat: Option<PatId>,
+        subpat: Option<PatId>,
     },
     TupleStruct {
         path: Option<Path>,
@@ -413,12 +413,10 @@ pub enum Pat {
 impl Pat {
     pub fn walk_child_pats(&self, mut f: impl FnMut(PatId)) {
         match self {
-            Pat::Range { .. }
-            | Pat::Lit(..)
-            | Pat::Path(..)
-            | Pat::Wild
-            | Pat::Missing
-            | Pat::Bind { .. } => {}
+            Pat::Range { .. } | Pat::Lit(..) | Pat::Path(..) | Pat::Wild | Pat::Missing => {}
+            Pat::Bind { subpat, .. } => {
+                subpat.iter().map(|pat| *pat).for_each(f);
+            }
             Pat::Tuple(args) | Pat::TupleStruct { args, .. } => {
                 args.iter().map(|pat| *pat).for_each(f);
             }
@@ -833,11 +831,11 @@ impl ExprCollector {
                     .map(|nr| nr.as_name())
                     .unwrap_or_else(Name::missing);
                 let annotation = BindingAnnotation::new(bp.is_mutable(), bp.is_ref());
-                let sub_pat = bp.pat().map(|subpat| self.collect_pat(subpat));
+                let subpat = bp.pat().map(|subpat| self.collect_pat(subpat));
                 Pat::Bind {
                     name,
                     mode: annotation,
-                    sub_pat,
+                    subpat,
                 }
             }
             ast::PatKind::TupleStructPat(p) => {
@@ -928,7 +926,7 @@ pub(crate) fn collect_fn_body_syntax(node: &ast::FnDef) -> BodySyntaxMapping {
                 Pat::Bind {
                     name: Name::self_param(),
                     mode: BindingAnnotation::Unannotated,
-                    sub_pat: None,
+                    subpat: None,
                 },
                 self_param,
             );
diff --git a/crates/ra_hir/src/ty.rs b/crates/ra_hir/src/ty.rs
index bc842dd26..57fd1ed2a 100644
--- a/crates/ra_hir/src/ty.rs
+++ b/crates/ra_hir/src/ty.rs
@@ -904,39 +904,39 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         }
     }
 
-    fn infer_tuple_struct(&mut self, path: Option<&Path>, sub_pats: &[PatId]) -> Ty {
+    fn infer_tuple_struct(&mut self, path: Option<&Path>, subpats: &[PatId]) -> Ty {
         let (ty, fields) = if let Some(x) = self.resolve_fields(path) {
             x
         } else {
             return Ty::Unknown;
         };
 
-        if fields.len() != sub_pats.len() {
+        if fields.len() != subpats.len() {
             return Ty::Unknown;
         }
 
-        for (&sub_pat, field) in sub_pats.iter().zip(fields.iter()) {
+        for (&subpat, field) in subpats.iter().zip(fields.iter()) {
             let sub_ty = self.make_ty(&field.type_ref);
-            self.infer_pat(sub_pat, &Expectation::has_type(sub_ty));
+            self.infer_pat(subpat, &Expectation::has_type(sub_ty));
         }
 
         ty
     }
 
-    fn infer_struct(&mut self, path: Option<&Path>, sub_pats: &[FieldPat]) -> Ty {
+    fn infer_struct(&mut self, path: Option<&Path>, subpats: &[FieldPat]) -> Ty {
         let (ty, fields) = if let Some(x) = self.resolve_fields(path) {
             x
         } else {
             return Ty::Unknown;
         };
 
-        for sub_pat in sub_pats {
-            let matching_field = fields.iter().find(|field| field.name == sub_pat.name);
+        for subpat in subpats {
+            let matching_field = fields.iter().find(|field| field.name == subpat.name);
 
             if let Some(field) = matching_field {
                 let typeref = &field.type_ref;
                 let sub_ty = self.make_ty(typeref);
-                self.infer_pat(sub_pat.pat, &Expectation::has_type(sub_ty));
+                self.infer_pat(subpat.pat, &Expectation::has_type(sub_ty));
             }
         }
 
@@ -979,8 +979,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             }
             Pat::TupleStruct {
                 path: ref p,
-                args: ref sub_pats,
-            } => self.infer_tuple_struct(p.as_ref(), sub_pats),
+                args: ref subpats,
+            } => self.infer_tuple_struct(p.as_ref(), subpats),
             Pat::Struct {
                 path: ref p,
                 args: ref fields,
@@ -995,12 +995,15 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             Pat::Bind {
                 mode,
                 name: _name,
-                sub_pat,
+                subpat,
             } => {
-                let subty = if let Some(subpat) = sub_pat {
+                let subty = if let Some(subpat) = subpat {
                     self.infer_pat(*subpat, expected)
                 } else {
-                    Ty::Unknown
+                    let ty = self.new_type_var();
+                    self.unify(&ty, &expected.ty);
+                    let ty = self.resolve_ty_as_possible(ty);
+                    ty
                 };
 
                 match mode {
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index e817a8da9..fc4054159 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -359,7 +359,7 @@ fn test(x: &str, y: isize) {
 }
 
 #[test]
-fn infer_simple_pattern() {
+fn infer_pattern() {
     check_inference(
         r#"
 fn test(x: &i32) {
@@ -381,6 +381,7 @@ fn test(x: &i32) {
     let ref ref_to_x = x;
     let mut mut_x = x;
     let ref mut mut_ref_to_x = x;
+    let k = mut_ref_to_x;
 }
 "#,
         "pattern.txt",
@@ -408,6 +409,9 @@ fn test() {
         E::A { x } => x,
         E::B => 1,
     };
+
+    let ref d @ E::A { .. } = e;
+    d;
 }
 "#,
         "adt_pattern.txt",
diff --git a/crates/ra_hir/src/ty/tests/data/adt_pattern.txt b/crates/ra_hir/src/ty/tests/data/adt_pattern.txt
index 3b9b9a078..2daf9647b 100644
--- a/crates/ra_hir/src/ty/tests/data/adt_pattern.txt
+++ b/crates/ra_hir/src/ty/tests/data/adt_pattern.txt
@@ -1,4 +1,4 @@
-[68; 221) '{     ...  }; }': ()
+[68; 262) '{     ...  d; }': ()
 [78; 79) 'e': E
 [82; 95) 'E::A { x: 3 }': E
 [92; 93) '3': usize
@@ -16,3 +16,7 @@
 [191; 192) 'x': usize
 [202; 206) 'E::B': E
 [210; 211) '1': usize
+[229; 248) 'ref d ...{ .. }': &E
+[237; 248) 'E::A { .. }': E
+[251; 252) 'e': E
+[258; 259) 'd': &E
diff --git a/crates/ra_hir/src/ty/tests/data/pattern.txt b/crates/ra_hir/src/ty/tests/data/pattern.txt
index 8b7c967c4..966289aaf 100644
--- a/crates/ra_hir/src/ty/tests/data/pattern.txt
+++ b/crates/ra_hir/src/ty/tests/data/pattern.txt
@@ -1,5 +1,5 @@
 [9; 10) 'x': &i32
-[18; 259) '{     ...c }; }': ()
+[18; 369) '{     ...o_x; }': ()
 [28; 29) 'y': &i32
 [32; 33) 'x': &i32
 [43; 45) '&z': &i32
@@ -37,3 +37,11 @@
 [246; 251) 'a + b': u64
 [250; 251) 'b': u64
 [253; 254) 'c': i32
+[267; 279) 'ref ref_to_x': &&i32
+[282; 283) 'x': &i32
+[293; 302) 'mut mut_x': &i32
+[305; 306) 'x': &i32
+[316; 336) 'ref mu...f_to_x': &mut &i32
+[339; 340) 'x': &i32
+[350; 351) 'k': &mut &i32
+[354; 366) 'mut_ref_to_x': &mut &i32