Address code review comments

compiler/rustc_codegen_cranelift/src/value_and_place.rs

@@ -816,6 +816,7 @@ pub(crate) fn assert_assignable<'tcx>(
             // fn(&T) -> for<'l> fn(&'l T) is allowed
         }
         (&ty::Dynamic(from_traits, _, _from_kind), &ty::Dynamic(to_traits, _, _to_kind)) => {
+            // FIXME(dyn-star): Do the right thing with DynKinds
             for (from, to) in from_traits.iter().zip(to_traits) {
                 let from =
                     fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), from);