4 files changed, 40 insertions, 37 deletions

diff --git a/crates/hir_ty/src/infer/coerce.rs b/crates/hir_ty/src/infer/coerce.rs
index 765a02b1c..03b97e7db 100644
--- a/crates/hir_ty/src/infer/coerce.rs
+++ b/crates/hir_ty/src/infer/coerce.rs
@@ -76,17 +76,17 @@ impl<'a> InferenceContext<'a> {
         // way around first would mean we make the type variable `!`, instead of
         // just marking it as possibly diverging.
         if self.coerce(&ty2, &ty1) {
-            ty1.clone()
+            ty1
         } else if self.coerce(&ty1, &ty2) {
-            ty2.clone()
+            ty2
         } else {
             if let Some(id) = id {
                 self.result
                     .type_mismatches
-                    .insert(id.into(), TypeMismatch { expected: ty1.clone(), actual: ty2.clone() });
+                    .insert(id.into(), TypeMismatch { expected: ty1.clone(), actual: ty2 });
             }
             cov_mark::hit!(coerce_merge_fail_fallback);
-            ty1.clone()
+            ty1
         }
     }
 
@@ -183,7 +183,7 @@ impl<'a> InferenceContext<'a> {
         // details of coercion errors though, so I think it's useful to leave
         // the structure like it is.
 
-        let canonicalized = self.canonicalize(from_ty.clone());
+        let canonicalized = self.canonicalize(from_ty);
         let autoderef = autoderef::autoderef(
             self.db,
             self.resolver.krate(),
@@ -389,7 +389,7 @@ impl<'a> InferenceContext<'a> {
                 // The CoerceUnsized trait should have two generic params: Self and T.
                 return Err(TypeError);
             }
-            b.push(coerce_from.clone()).push(to_ty.clone()).build()
+            b.push(coerce_from).push(to_ty.clone()).build()
         };
 
         let goal: InEnvironment<DomainGoal> =
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 08c05c67c..41ef45326 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -44,7 +44,7 @@ impl<'a> InferenceContext<'a> {
             if !could_unify {
                 self.result.type_mismatches.insert(
                     tgt_expr.into(),
-                    TypeMismatch { expected: expected_ty.clone(), actual: ty.clone() },
+                    TypeMismatch { expected: expected_ty, actual: ty.clone() },
                 );
             }
         }
@@ -57,15 +57,14 @@ impl<'a> InferenceContext<'a> {
         let ty = self.infer_expr_inner(expr, &expected);
         let ty = if let Some(target) = expected.only_has_type(&mut self.table) {
             if !self.coerce(&ty, &target) {
-                self.result.type_mismatches.insert(
-                    expr.into(),
-                    TypeMismatch { expected: target.clone(), actual: ty.clone() },
-                );
+                self.result
+                    .type_mismatches
+                    .insert(expr.into(), TypeMismatch { expected: target, actual: ty.clone() });
                 // Return actual type when type mismatch.
                 // This is needed for diagnostic when return type mismatch.
                 ty
             } else {
-                target.clone()
+                target
             }
         } else {
             ty
@@ -120,7 +119,7 @@ impl<'a> InferenceContext<'a> {
     }
 
     fn infer_expr_inner(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
-        self.db.check_canceled();
+        self.db.unwind_if_cancelled();
 
         let body = Arc::clone(&self.body); // avoid borrow checker problem
         let ty = match &body[tgt_expr] {
@@ -805,7 +804,7 @@ impl<'a> InferenceContext<'a> {
                     None => self.table.new_float_var(),
                 },
             },
-            Expr::MacroStmts { tail } => self.infer_expr(*tail, expected),
+            Expr::MacroStmts { tail } => self.infer_expr_inner(*tail, expected),
         };
         // use a new type variable if we got unknown here
         let ty = self.insert_type_vars_shallow(ty);
@@ -891,17 +890,21 @@ impl<'a> InferenceContext<'a> {
                 method_name,
             )
         });
-        let (derefed_receiver_ty, method_ty, def_generics) = match resolved {
+        let (derefed_receiver_ty, method_ty, substs) = match resolved {
             Some((ty, func)) => {
                 let ty = canonicalized_receiver.decanonicalize_ty(ty);
-                self.write_method_resolution(tgt_expr, func);
-                (ty, self.db.value_ty(func.into()), Some(generics(self.db.upcast(), func.into())))
+                let generics = generics(self.db.upcast(), func.into());
+                let substs = self.substs_for_method_call(generics, generic_args, &ty);
+                self.write_method_resolution(tgt_expr, func, substs.clone());
+                (ty, self.db.value_ty(func.into()), substs)
             }
-            None => (receiver_ty, Binders::empty(&Interner, self.err_ty()), None),
+            None => (
+                receiver_ty,
+                Binders::empty(&Interner, self.err_ty()),
+                Substitution::empty(&Interner),
+            ),
         };
-        let substs = self.substs_for_method_call(def_generics, generic_args, &derefed_receiver_ty);
         let method_ty = method_ty.substitute(&Interner, &substs);
-        let method_ty = self.insert_type_vars(method_ty);
         self.register_obligations_for_call(&method_ty);
         let (expected_receiver_ty, param_tys, ret_ty) = match method_ty.callable_sig(self.db) {
             Some(sig) => {
@@ -950,23 +953,21 @@ impl<'a> InferenceContext<'a> {
 
     fn substs_for_method_call(
         &mut self,
-        def_generics: Option<Generics>,
+        def_generics: Generics,
         generic_args: Option<&GenericArgs>,
         receiver_ty: &Ty,
     ) -> Substitution {
         let (parent_params, self_params, type_params, impl_trait_params) =
-            def_generics.as_ref().map_or((0, 0, 0, 0), |g| g.provenance_split());
+            def_generics.provenance_split();
         assert_eq!(self_params, 0); // method shouldn't have another Self param
         let total_len = parent_params + type_params + impl_trait_params;
         let mut substs = Vec::with_capacity(total_len);
         // Parent arguments are unknown, except for the receiver type
-        if let Some(parent_generics) = def_generics.as_ref().map(|p| p.iter_parent()) {
-            for (_id, param) in parent_generics {
-                if param.provenance == hir_def::generics::TypeParamProvenance::TraitSelf {
-                    substs.push(receiver_ty.clone());
-                } else {
-                    substs.push(self.err_ty());
-                }
+        for (_id, param) in def_generics.iter_parent() {
+            if param.provenance == hir_def::generics::TypeParamProvenance::TraitSelf {
+                substs.push(receiver_ty.clone());
+            } else {
+                substs.push(self.table.new_type_var());
             }
         }
         // handle provided type arguments
@@ -989,7 +990,7 @@ impl<'a> InferenceContext<'a> {
         };
         let supplied_params = substs.len();
         for _ in supplied_params..total_len {
-            substs.push(self.err_ty());
+            substs.push(self.table.new_type_var());
         }
         assert_eq!(substs.len(), total_len);
         Substitution::from_iter(&Interner, substs)
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index 9c8e3b6ae..83e0a7a9e 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -196,7 +196,7 @@ impl<'a> InferenceContext<'a> {
                 let inner_ty = if let Some(subpat) = subpat {
                     self.infer_pat(*subpat, &expected, default_bm)
                 } else {
-                    expected.clone()
+                    expected
                 };
                 let inner_ty = self.insert_type_vars_shallow(inner_ty);
 
@@ -266,10 +266,9 @@ impl<'a> InferenceContext<'a> {
         // use a new type variable if we got error type here
         let ty = self.insert_type_vars_shallow(ty);
         if !self.unify(&ty, &expected) {
-            self.result.type_mismatches.insert(
-                pat.into(),
-                TypeMismatch { expected: expected.clone(), actual: ty.clone() },
-            );
+            self.result
+                .type_mismatches
+                .insert(pat.into(), TypeMismatch { expected: expected, actual: ty.clone() });
         }
         self.write_pat_ty(pat, ty.clone());
         ty
diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs
index f8233cac3..ea5684229 100644
--- a/crates/hir_ty/src/infer/unify.rs
+++ b/crates/hir_ty/src/infer/unify.rs
@@ -295,8 +295,11 @@ impl<'a> InferenceTable<'a> {
         .expect("fold failed unexpectedly")
     }
 
-    pub(crate) fn resolve_ty_completely(&mut self, ty: Ty) -> Ty {
-        self.resolve_with_fallback(ty, |_, _, d, _| d)
+    pub(crate) fn resolve_completely<T>(&mut self, t: T) -> T::Result
+    where
+        T: HasInterner<Interner = Interner> + Fold<Interner>,
+    {
+        self.resolve_with_fallback(t, |_, _, d, _| d)
     }
 
     /// Unify two types and register new trait goals that arise from that.