https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81917
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |ice-on-valid-code
Last reconfirmed|2017-08-22 00:00:00 |2019-6-24
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
FWIW a user has sent me an ice-on-valid reproducer for this as well. After
reduce it's:
template <int a> struct b { static constexpr int c = a; };
template <bool e> using d = b<e>;
template <int> struct h { template <typename g, typename> using f = g; };
template <bool, typename i> using j = i;
template <typename> using k = void;
template <template <class...> class l> struct r {
template <typename... n> using f = l<n...>;
};
template <typename o, typename... p> using aa = typename o::template f<p...>;
template <typename g> struct s {
template <typename... q> using f = aa<g, q...>;
};
template <typename m, typename o> struct t {
template <typename... p>
using f = typename h<sizeof...(
p)>::template f<o, void>::template f<typename m::template f<p>...>;
};
template <typename o, typename... p> struct ab {
template <typename... q> using f = typename o::template f<q..., p...>;
};
template <typename o, typename... p> struct ac {
template <typename... q> using f = typename o::template f<p..., q...>;
};
template <typename... n> using ad = ab<r<ac>, n...>;
struct ae;
struct v {
template <typename... af> using f = t<ad<ae>, r<s>>::f<af...>;
};
template <typename, template <typename...> class, class...>
struct IsValidT_impl {};
template <template <typename...> class g, typename... p>
struct IsValidT_impl<k<g<p...>>, g, p...> : d<true> {};
struct w {
template <template <typename...> class g, class... p>
using f = IsValidT_impl<void, g, p...>;
};
template <template <class> class ag> struct x {
template <typename... g> using f = ag<g...>;
};
template <typename, typename, typename, typename ah, typename... ai>
struct y : aa<v, ai...>::template f<int> {
using aj = aa<ah, ae>;
aj ak();
};
namespace f {
template <typename g, typename al> using am = decltype(g().ak().an(0, al()));
struct z {
template <typename g> friend auto operator==(j<w::f<am, ae, g>::c, ae>, g) {}
template <typename g> friend auto operator==(g, j<w::f<am, ae, g>::c, ae>) {}
};
template <typename, typename> struct ao : z {};
} // namespace f
using ap = r<f::ao>;
struct aq {
template <typename ar, typename as> auto an(ar at, as au) { return at == au;
}
};
namespace av {
template <typename> struct aw : aq {};
} // namespace av
using ax = x<av::aw>;
namespace ay {
template <typename> struct az : aa<ax, int> {};
} // namespace ay
using u = x<ay::az>;
namespace ba {
template <typename> struct bb : aa<u, int> {};
} // namespace ba
using bc = x<ba::bb>;
struct ae : y<int, int, int, bc, ap> {};
int main() {
ae a;
a == 0;
}
This compiles OK since r257542 but still fails with GCC 7:
81917.ii: In instantiation of 'struct IsValidT_impl<void, f::am, ae, ae>':
81917.ii:49:37: required by substitution of 'template<class g> auto
f::operator==(g, j<IsValidT_impl<void, f::am, ae, g>::c, ae>) [with g = ae]'
81917.ii:72:8: required from here
81917.ii:32:8: error: redefinition of 'struct IsValidT_impl<void, f::am, ae,
ae>'
struct IsValidT_impl<k<g<p...>>, g, p...> : d<true> {};
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
81917.ii:32: confused by earlier errors, bailing out
Is the fix safe to backport to gcc-7-branch?
