The FakeRttiSupport class contains a workaround in its validate_tag function. Specifically, the argument type is uintx rather than the more appropriate TagType. This was needed to avoid a -Wtypes-limit warning when building on MacOSX when instantiated TagType's range is always in the checked range. This warning should be considered spurious, since it involves a template parameter type; there is an old gcc bug about this (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=11856), which was fixed in gcc 4.8. Once we're no longer using any compilers which generate this spurious warning, we can remove the workaround.