[Bug c++/64297] [5 Regression] ICE: canonical types differ for identical types

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64297

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> ---
struct A {
  typedef int X;
  template <int> X m_fn1() const;
};
template <typename> struct is_function {};
is_function<int() const &> i;
struct D {
  template <typename Y, typename = is_function<Y>> D(Y);
} b(&A::m_fn1<0>);