https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36887
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Simplified testcase: #pragma GCC poison a int a; GCC outputs: <source>:2:5: error: attempt to use poisoned "a" 2 | int a; | ^ But not the location of the #pragma which would be useful to debug why it was poisoned.