https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122192
--- Comment #4 from Vincent X <gulackeg at gmail dot com> --- base-specifiers (and the corresponding mem-initializer-ids) have two properties: 1. Name lookup within them is type-only, as stated by Patrick above. Whether the name is dependent or not should not change this. 2. The `typename` disambiguator is disallowed within them by their syntax, since it is redundant semantically (we already ignore non-type names as per Property 1). The observation from the above code is that, seemingly, GCC 13+ and Clang haven't implemented Property 1 for dependent names.
