[Bug c++/108099] ICE when parsing signed __int128_t typedef

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108099

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #2)
> (In reply to Jonathan Wakely from comment #1)
> > __int128_t is already a typedef, so you can't add a signed or unsigned
> > qualifier to it.
> 
> i.e. the same reason this doesn't work:
> 
> using I = int;
> signed I i = 0;

Hmm, actually g++ *does* allow this, unless you use -pedantic-errors:

using I = int;
using II = signed I;

It's not valid C++ though.