[Bug c++/107085] __reference_constructs_from_temporary does not detect static up-cast

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107085

--- Comment #10 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Even more simplified:

struct X {
  virtual void f();
};
struct Z : X {};
constexpr X x = X(Z());

I guess we shouldn't try to force_elide X::X(X&&) here because X is a
potentially-overlapping subobject.