Subst gat normalize pred correctly

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1958,7 +1958,7 @@ pub(super) fn check_type_bounds<'tcx>(
     let container_id = impl_ty.container_id(tcx);
 
     let rebased_substs = impl_ty_substs.rebase_onto(tcx, container_id, impl_trait_ref.substs);
-    let impl_ty_value = tcx.type_of(impl_ty.def_id).subst_identity();
+    let impl_ty_value = tcx.type_of(impl_ty.def_id).subst(tcx, impl_ty_substs);
 
     let param_env = tcx.param_env(impl_ty.def_id);
 

tests/ui/generic-associated-types/gat-bounds-normalize-pred.rs

@@ -0,0 +1,17 @@
+// check-pass
+
+trait Foo {
+    type Assoc<T>: PartialEq<Self::Assoc<i32>>;
+}
+
+impl Foo for () {
+    type Assoc<T> = Wrapper<T>;
+}
+
+struct Wrapper<T>(T);
+
+impl<T> PartialEq<Wrapper<i32>> for Wrapper<T> {
+    fn eq(&self, _other: &Wrapper<i32>) -> bool { true }
+}
+
+fn main() {}