https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84782
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2018-03-12
Ever confirmed|0 |1
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced:
struct c { static constexpr bool value = false; };
template <typename a> a declval();
template <typename g, typename = decltype(declval<g>() = 1)> // #1
void h(int);
template <typename>
c h(...);
template<typename T> using i = decltype(h<T>(0));
struct k {
k(const k &) = default;
void operator=(k &&) = delete;
};
struct l : k {
using k::operator=; // #2
};
struct G {
G(const G &);
l q;
};
int j = i<G>::value;
G::G(const G &) = default;
x.cc:28:1: note: ‘G::G(const G&)’ is implicitly deleted because the default
definition would be ill-formed:
G::G(const G &) = default;
^
x.cc:28:1: error: use of deleted function ‘constexpr l::l(const l&)’
x.cc:17:7: note: ‘constexpr l::l(const l&)’ is implicitly declared as deleted
because ‘l’ declares a move constructor or move assignment operator
class l : k {
^
The error is malformed for a start, we issue a note that doesn't follow any
error.
There seem to be two things involved here. The error is apparently triggered by
the SFINAE check at #1 which should silently fail instead of giving an error.
It seems to be an error because of the "using k::operator=;" line at #2 which
should have no effect.
