[Bug c++/95299] New: sorry, unimplemented: mangling typename_type

[jonathan.poelen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95299

            Bug ID: 95299
           Summary: sorry, unimplemented: mangling typename_type
           Product: gcc
           Version: 9.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jonathan.poelen at gmail dot com
  Target Milestone: ---

Since version 7 to trunk, the following code no longer compiles
(https://godbolt.org/z/T9gpw4)

template<int n>
struct func_select
{
  using type = void;
};

struct func
{
  template<class... seqs>
  using f = typename func_select<sizeof...(seqs)>::type;
};

template<class>
struct to_int
{
  using type = int;
};

template<class... T>
func::f<typename to_int<T>::type...> bar(T...)
{}

int main()
{
  bar();
}