1 files changed, 30 insertions, 15 deletions

diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index f1cebbdb9..7a4268819 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -28,17 +28,18 @@ use hir_def::{
     AdtId, AssocItemId, DefWithBodyId, EnumVariantId, FieldId, FunctionId, HasModule, Lookup,
     TraitId, TypeAliasId, VariantId,
 };
-use hir_expand::{diagnostics::DiagnosticSink, name::name};
+use hir_expand::name::name;
 use la_arena::ArenaMap;
 use rustc_hash::FxHashMap;
 use stdx::impl_from;
 use syntax::SmolStr;
 
 use super::{DomainGoal, InEnvironment, ProjectionTy, TraitEnvironment, TraitRef, Ty};
+use crate::diagnostics_sink::DiagnosticSink;
 use crate::{
     db::HirDatabase, fold_tys, infer::diagnostics::InferenceDiagnostic,
-    lower::ImplTraitLoweringMode, to_assoc_type_id, AliasEq, AliasTy, Goal, Interner, TyBuilder,
-    TyExt, TyKind,
+    lower::ImplTraitLoweringMode, to_assoc_type_id, AliasEq, AliasTy, Goal, Interner, Substitution,
+    TyBuilder, TyExt, TyKind,
 };
 
 // This lint has a false positive here. See the link below for details.
@@ -132,7 +133,7 @@ impl Default for InternedStandardTypes {
 #[derive(Clone, PartialEq, Eq, Debug, Default)]
 pub struct InferenceResult {
     /// For each method call expr, records the function it resolves to.
-    method_resolutions: FxHashMap<ExprId, FunctionId>,
+    method_resolutions: FxHashMap<ExprId, (FunctionId, Substitution)>,
     /// For each field access expr, records the field it resolves to.
     field_resolutions: FxHashMap<ExprId, FieldId>,
     /// For each struct literal or pattern, records the variant it resolves to.
@@ -152,8 +153,8 @@ pub struct InferenceResult {
 }
 
 impl InferenceResult {
-    pub fn method_resolution(&self, expr: ExprId) -> Option<FunctionId> {
-        self.method_resolutions.get(&expr).copied()
+    pub fn method_resolution(&self, expr: ExprId) -> Option<(FunctionId, Substitution)> {
+        self.method_resolutions.get(&expr).cloned()
     }
     pub fn field_resolution(&self, expr: ExprId) -> Option<FieldId> {
         self.field_resolutions.get(&expr).copied()
@@ -284,14 +285,17 @@ impl<'a> InferenceContext<'a> {
         self.table.propagate_diverging_flag();
         let mut result = std::mem::take(&mut self.result);
         for ty in result.type_of_expr.values_mut() {
-            *ty = self.table.resolve_ty_completely(ty.clone());
+            *ty = self.table.resolve_completely(ty.clone());
         }
         for ty in result.type_of_pat.values_mut() {
-            *ty = self.table.resolve_ty_completely(ty.clone());
+            *ty = self.table.resolve_completely(ty.clone());
         }
         for mismatch in result.type_mismatches.values_mut() {
-            mismatch.expected = self.table.resolve_ty_completely(mismatch.expected.clone());
-            mismatch.actual = self.table.resolve_ty_completely(mismatch.actual.clone());
+            mismatch.expected = self.table.resolve_completely(mismatch.expected.clone());
+            mismatch.actual = self.table.resolve_completely(mismatch.actual.clone());
+        }
+        for (_, subst) in result.method_resolutions.values_mut() {
+            *subst = self.table.resolve_completely(subst.clone());
         }
         result
     }
@@ -300,8 +304,8 @@ impl<'a> InferenceContext<'a> {
         self.result.type_of_expr.insert(expr, ty);
     }
 
-    fn write_method_resolution(&mut self, expr: ExprId, func: FunctionId) {
-        self.result.method_resolutions.insert(expr, func);
+    fn write_method_resolution(&mut self, expr: ExprId, func: FunctionId, subst: Substitution) {
+        self.result.method_resolutions.insert(expr, (func, subst));
     }
 
     fn write_field_resolution(&mut self, expr: ExprId, field: FieldId) {
@@ -554,7 +558,13 @@ impl<'a> InferenceContext<'a> {
 
             self.infer_pat(*pat, &ty, BindingMode::default());
         }
-        let return_ty = self.make_ty_with_mode(&data.ret_type, ImplTraitLoweringMode::Disallowed); // FIXME implement RPIT
+        let error_ty = &TypeRef::Error;
+        let return_ty = if data.is_async() {
+            data.async_ret_type.as_deref().unwrap_or(error_ty)
+        } else {
+            &*data.ret_type
+        };
+        let return_ty = self.make_ty_with_mode(return_ty, ImplTraitLoweringMode::Disallowed); // FIXME implement RPIT
         self.return_ty = return_ty;
     }
 
@@ -575,9 +585,14 @@ impl<'a> InferenceContext<'a> {
     }
 
     fn resolve_ops_try_ok(&self) -> Option<TypeAliasId> {
+        // FIXME resolve via lang_item once try v2 is stable
         let path = path![core::ops::Try];
         let trait_ = self.resolver.resolve_known_trait(self.db.upcast(), &path)?;
-        self.db.trait_data(trait_).associated_type_by_name(&name![Ok])
+        let trait_data = self.db.trait_data(trait_);
+        trait_data
+            // FIXME remove once try v2 is stable
+            .associated_type_by_name(&name![Ok])
+            .or_else(|| trait_data.associated_type_by_name(&name![Output]))
     }
 
     fn resolve_ops_neg_output(&self) -> Option<TypeAliasId> {
@@ -790,11 +805,11 @@ impl std::ops::BitOrAssign for Diverges {
 
 mod diagnostics {
     use hir_def::{expr::ExprId, DefWithBodyId};
-    use hir_expand::diagnostics::DiagnosticSink;
 
     use crate::{
         db::HirDatabase,
         diagnostics::{BreakOutsideOfLoop, NoSuchField},
+        diagnostics_sink::DiagnosticSink,
     };
 
     #[derive(Debug, PartialEq, Eq, Clone)]