[Bug c++/79264] [7 Regression] ICE verify_type failed

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79264

--- Comment #2 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
Created attachment 40625
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40625&action=edit
Reduced testcase

./obj/x86_64/gcc/cc1plus -fconcepts -std=c++1z -g3 79264-dbg.ii 

It's very easy to turn this into a different seg fault somewhere in the
gimplifier.  Sadly my 67273 patch doesn't fix this one.