Merge #8945

8945: fix: Make expected type work in more situations r=flodiebold a=flodiebold

Also makes call info show the correct types for generic methods.

![2021-05-23-182952_1134x616_scrot](https://user-images.githubusercontent.com/906069/119269023-dd5a5b00-bbf5-11eb-993a-b6e122c3b9a6.png)
![2021-05-23-183117_922x696_scrot](https://user-images.githubusercontent.com/906069/119269025-dfbcb500-bbf5-11eb-983c-fc415b8428e0.png)


Co-authored-by: Florian Diebold <[email protected]>

1 files changed, 5 insertions, 2 deletions

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.