[Bug c++/77563] [5/6/7 Regression] explicit constructor breaks narrowing conversion overload resolution

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77563

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced:

struct A {
  A(int) {}
  A(unsigned) {}  // Comment to make it work

  explicit A(long) {}  // Comment to make it work
};

void f(A) { }

int main() {
  f(2);
  f(3l);
}