[Bug c++/117317] [12/13/14/15 Regression] ICE on call to virtual constexpr function via comparison operator in CRTP with multiple inheritance with template since r12-4202-g09d886e671f223

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117317

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This really isn't specific to defaulted comparison operators,
struct C {
  constexpr virtual bool foo () const = 0;
};
struct A : public C {};
struct B : public C {};
template <int>
struct D : A, B
{
  constexpr D () {}
  constexpr bool foo () const override { return true; }
};
constexpr D<0> d;
static_assert (d.foo (), "");
ICEs already since r0-110035-g2fda8e144a7db5b, since
r0-113261-g99c18869efe4d723
in that exact use_thunk spot.

Maybe emit_associated_thunks should do nothing on
!DECL_INTERFACE_KNOWN (fn) && DECL_DEFER_OUTPUT (fn)
functions?