[Bug c++/115716] [11/12/13/14/15 regression] internal compiler error: tree check: accessed elt 2 of 'tree_vec' with 1 elts in tsubst, at cp/pt.cc:16364

[mpolacek at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115716

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I suppose the problem is that we do not detect too many template parameters
here:

template<typename T>
struct S {
  template<typename U>
  struct N { };
};

template<>
template<typename U, typename X> // bad
struct S<int>::N { };

while clang++ says:

q.C:8:1: error: too many template parameters in template redeclaration
    8 | template<typename U, typename X>
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
q.C:3:3: note: previous template declaration is here
    3 |   template<typename U>
      |   ^~~~~~~~~~~~~~~~~~~~