[Bug c++/120969] two consecutive '[' shall only introduce an attribute before '[' token

[f.heckenbach--- via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120969

--- Comment #2 from Frank Heckenbach <f.heckenb...@fh-soft.de> ---
(In reply to Andrew Pinski from comment #1)
> I am almost want to close this as won't fix since -fconcepts-ts has already
> been removed in GCC 15 which was released 3 months ago.

So much for the "deprecation period"
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120917#c13) ...