https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94842
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Indeed: _Atomic float x = 5; void bar (float y[(int) (x += 2)]) { } is accepted while _Atomic float x = 5; void foo (void) { void bar (float y[(int) (x += 2)]) {} } ICEs. The problem is that create_artificial_label called from build_atomic_assign from the nested function parameter declaration parsing sets LABEL_DECL to current_function_decl