[Bug c++/79653] [5/6/7 Regression] ICE on invalid c++ code in cp_check_const_attributes in cp/decl2.c:1423

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79653

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
cp_check_const_attributes should check ARG before accessing its TREE_VALUE.