[Bug c++/92338] double/float thought (ambiguous) candidate for C-array index. (Non numeric types aren't.)

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92338

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
All compilers agree, because it's what the standard says should happen.