address review

compiler/rustc_middle/src/query/mod.rs

@@ -1644,6 +1644,11 @@ rustc_queries! {
         desc { "normalizing `{:?}`", goal }
     }
 
+    // FIXME: Implement `normalize_generic_arg_after_erasing_regions` and
+    // `normalize_mir_const_after_erasing_regions` in terms of
+    // `try_normalize_generic_arg_after_erasing_regions` and
+    // `try_normalize_mir_const_after_erasing_regions`, respectively.
+
     /// Do not call this query directly: invoke `normalize_erasing_regions` instead.
     query normalize_generic_arg_after_erasing_regions(
         goal: ParamEnvAnd<'tcx, GenericArg<'tcx>>