Make Ty wrap TyKind in an Arc

... like it will be in Chalk. We still keep `interned_mut` and
`into_inner` methods that will probably not exist with Chalk.

This worsens performance slightly (5ginstr inference on RA), but doesn't
include other simplifications we can do yet.

1 files changed, 1 insertions, 1 deletions

diff --git a/crates/hir_ty/src/infer/coerce.rs b/crates/hir_ty/src/infer/coerce.rs
index 36670043a..435f7d0db 100644
--- a/crates/hir_ty/src/infer/coerce.rs
+++ b/crates/hir_ty/src/infer/coerce.rs
@@ -71,7 +71,7 @@ impl<'a> InferenceContext<'a> {
         }
 
         // Pointer weakening and function to pointer
-        match (&mut from_ty.0, to_ty.interned(&Interner)) {
+        match (from_ty.interned_mut(), to_ty.interned(&Interner)) {
             // `*mut T` -> `*const T`
             // `&mut T` -> `&T`
             (TyKind::Raw(m1, ..), TyKind::Raw(m2 @ Mutability::Not, ..))