[Bug c/97154] gcc/c/c-decl.c:5729:38: error: Dereference of an invalid iterator

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97154

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This looks valid to me.
spec.empty () || spec.end ()[-1] != ' '
Means if it empty or the last element is a space.