message: Fix assert_assignable
diff: @@ -406,6 +406,10 @@ fn assert_assignable<'tcx>(
  to_ty: Ty<'tcx>,
  ) {
  match (&from_ty.kind, &to_ty.kind) {
  + (ty::Ref(_, a, _), ty::Ref(_, b, _))
  + | (ty::RawPtr(TypeAndMut { ty: a, mutbl: _}), ty::RawPtr(TypeAndMut { ty: b, mutbl: _})) => {
  + assert_assignable(fx, a, b);
  + }
  (ty::FnPtr(_), ty::FnPtr(_)) => {
  let from_sig = fx.tcx.normalize_erasing_late_bound_regions(
  ParamEnv::reveal_all(),
  