make compare_const_impl a query and use it in instance.rs

compiler/rustc_middle/src/query/mod.rs

@@ -2100,4 +2100,10 @@ rustc_queries! {
     query permits_zero_init(key: TyAndLayout<'tcx>) -> bool {
         desc { "checking to see if {:?} permits being left zeroed", key.ty }
     }
+
+    query compare_assoc_const_impl_item_with_trait_item(
+        key: (&'tcx ty::AssocItem, &'tcx ty::AssocItem, ty::TraitRef<'tcx>)
+    ) -> Result<(), ErrorGuaranteed> {
+        desc { |tcx| "checking assoc const `{}` has the same type as trait item", tcx.def_path_str(key.0.def_id) }
+    }
 }