[Bug c++/93297] internal compiler error: in set_constraints, at cp/constraint.cc:

[john at mcfarlane dot name via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93297

--- Comment #9 from John McFarlane <john at mcfarlane dot name> ---
And here is an ICE in 10.2: 

   struct a;
   template <typename = int> class b;
   template <class> b()->b<>;
   template <int> using c = b<a>;
   static_assert(c{}

CL: g++ -v -std=c++2a source.cpp
Online: https://godbolt.org/z/54aTr6