[Bug c++/87480] [8/9 Regression] SFINAE constructor not matched, only in templated function

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87480

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |8.3

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Slightly further reduced (it happens for any function template, not just
constructors):

template<typename T> T&& declval();

template <typename T, typename = decltype(declval<T>().d)> void f(T) { }

struct A {
  double d;
};

#ifndef FIX
template <typename>
#endif
void j(A& a) {
  f(a);
}