Merge #8687

8687: fix: closure unify without check ClosureId r=lnicola a=komonad

Previously, the unification of closure types is blocked by `Ty.equals_ctor` which compares the ClosureId of the closures. Here is a workaround to allow closures to unify their substitutions.

Fixes #8604.

Co-authored-by: Comonad <[email protected]>

1 files changed, 4 insertions, 0 deletions

diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs
index a887e20b0..d8e0b4320 100644
--- a/crates/hir_ty/src/infer/unify.rs
+++ b/crates/hir_ty/src/infer/unify.rs
@@ -332,6 +332,10 @@ impl InferenceTable {
                 | (TyKind::Slice(ty1), TyKind::Slice(ty2)) => self.unify_inner(ty1, ty2, depth + 1),
                 _ => true, /* we checked equals_ctor already */
             }
+        } else if let (TyKind::Closure(.., substs1), TyKind::Closure(.., substs2)) =
+            (ty1.kind(&Interner), ty2.kind(&Interner))
+        {
+            self.unify_substs(substs1, substs2, depth + 1)
         } else {
             self.unify_inner_trivial(&ty1, &ty2, depth)
         }