[Bug c++/70635] [4.9/5/6 Regression] ICE on (and rejects) valid code on x86_64-linux-gnu: Segmentation fault (program cc1plus)

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70635

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> ---
I think we can simply restrict the same_type_p call to type_decls with
TREE_TYPE with CLASS_TYPE_P true or something very close. I'm testing a patch.