https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81932
--- Comment #16 from Paul Smith <psmith at gnu dot org> --- I'm not familiar with the implementations but I'm not sure we can expect GDB to be able to handle this situation, at least not with any sort of efficiency. It's already a difficult part of GDB's job, looking up types quickly. I filed a bug a few years ago where GDB macros slowed down by over 94x (from a few seconds to over 11 minutes) due to a symbol lookup issue: it's a very sensitive area. Adding more complexity to this and asking GDB to try one variation of a given type after another until it finds one seems less than optimal. Even if it's decided that a change does need to happen on the GDB side, hopefully GCC will continue to generate the expected debugging symbols until that change is made and published in GDB.
