https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94061
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |ppalka at gcc dot gnu.org
--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to Frank Heckenbach from comment #1)
> I ran into the same problem.
>
> Interestingly, clang also seems to reject it, so maybe it is wrong by the
> letter of the standard? Though it would seem strange to me -- after all,
> when manually implementing B::operator<=> a protected operator in A will do
> fine.
How do you define it? It works if we define it as
auto operator <=> (const B& b) const {
return A::operator<=>(b);
}
but not if it's defined as
auto operator <=> (const B& b) const {
return static_cast<const A&>(*this) <=> static_cast<const A&>(b);
}
According to [class.spaceship], IIUC the synthesized operator<=> looks more
similar to the latter invalid definition (invoking <=> recursively as an
operator expression on each pair of corresponding subobjects), so GCC/Clang
might be right to define it as deleted.
