From c2aefd5b95adb9e07919a11cdfcca45de79b5324 Mon Sep 17 00:00:00 2001
From: Florian Diebold <flodiebold@gmail.com>
Date: Thu, 29 Apr 2021 20:21:50 +0200
Subject: [PATCH] Don't look in super traits for <T as Trait>::Assoc

This isn't actually how it works, you have to specify the exact trait
that has the associated type.

Fixes #8686.
---
 crates/hir_ty/src/lower.rs            | 13 ++++++-------
 crates/hir_ty/src/tests/regression.rs |  8 ++++++++
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index d01933e6bae..c99dd8d0a46 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -414,17 +414,16 @@ pub(crate) fn lower_partly_resolved_path(
                     self.lower_trait_ref_from_resolved_path(trait_, resolved_segment, self_ty);
                 let ty = if remaining_segments.len() == 1 {
                     let segment = remaining_segments.first().unwrap();
-                    let found = associated_type_by_name_including_super_traits(
-                        self.db,
-                        trait_ref,
-                        &segment.name,
-                    );
+                    let found = self
+                        .db
+                        .trait_data(trait_ref.hir_trait_id())
+                        .associated_type_by_name(&segment.name);
                     match found {
-                        Some((super_trait_ref, associated_ty)) => {
+                        Some(associated_ty) => {
                             // FIXME handle type parameters on the segment
                             TyKind::Alias(AliasTy::Projection(ProjectionTy {
                                 associated_ty_id: to_assoc_type_id(associated_ty),
-                                substitution: super_trait_ref.substitution,
+                                substitution: trait_ref.substitution,
                             }))
                             .intern(&Interner)
                         }
diff --git a/crates/hir_ty/src/tests/regression.rs b/crates/hir_ty/src/tests/regression.rs
index add12c6dbe9..d14f5c9bb11 100644
--- a/crates/hir_ty/src/tests/regression.rs
+++ b/crates/hir_ty/src/tests/regression.rs
@@ -1039,6 +1039,14 @@ fn test() {
 }
         "#,
         expect![[r#"
+            144..152 'residual': R
+            365..366 'r': ControlFlow<B, !>
+            395..410 '{ ControlFlow }': ControlFlow<B, C>
+            397..408 'ControlFlow': ControlFlow<B, C>
+            424..482 '{     ...!>); }': ()
+            430..456 'Contro...sidual': fn from_residual<ControlFlow<u32, {unknown}>, ControlFlow<u32, !>>(ControlFlow<u32, !>) -> ControlFlow<u32, {unknown}>
+            430..479 'Contro...2, !>)': ControlFlow<u32, {unknown}>
+            457..478 'Contro...32, !>': ControlFlow<u32, !>
         "#]],
     );
 }
-- 
2.44.0