These deduction guides became useless with LWG 3282 (implemented in commit r10-6741) and so were removed by LWG 3404.
libstdc++-v3/ChangeLog: PR libstdc++/100044 * include/bits/ranges_util.h (__detail::__iterator_sentinel_pair): Remove helper concept. (subrange(_Pr), subrange(Pr, __make_unsigned_like<...>)): Remove deduction guides, as per LWG 3404. * testsuite/std/ranges/subrange/lwg3282_neg.cc: Check that class template argument deduction fails. Tested powerpc64le-linux. Committed to trunk. I'll backport this to gcc-10 too.
commit 7569ce583f540ae22c585cc5159e3b23deedd987 Author: Jonathan Wakely <jwak...@redhat.com> Date: Mon Apr 12 12:49:17 2021 libstdc++: Implement LWG 3404 for C++20 subrange [PR 100044] These deduction guides became useless with LWG 3282 (implemented in commit r10-6741) and so were removed by LWG 3404. libstdc++-v3/ChangeLog: PR libstdc++/100044 * include/bits/ranges_util.h (__detail::__iterator_sentinel_pair): Remove helper concept. (subrange(_Pr), subrange(Pr, __make_unsigned_like<...>)): Remove deduction guides, as per LWG 3404. * testsuite/std/ranges/subrange/lwg3282_neg.cc: Check that class template argument deduction fails. diff --git a/libstdc++-v3/include/bits/ranges_util.h b/libstdc++-v3/include/bits/ranges_util.h index ae53afd97bd..9d51e1b874e 100644 --- a/libstdc++-v3/include/bits/ranges_util.h +++ b/libstdc++-v3/include/bits/ranges_util.h @@ -186,11 +186,6 @@ namespace ranges && __convertible_to_non_slicing<_Up, tuple_element_t<0, _Tp>> && convertible_to<_Vp, tuple_element_t<1, _Tp>>; - template<typename _Tp> - concept __iterator_sentinel_pair - = !range<_Tp> && __pair_like<_Tp> - && sentinel_for<tuple_element_t<1, _Tp>, tuple_element_t<0, _Tp>>; - } // namespace __detail enum class subrange_kind : bool { unsized, sized }; @@ -352,16 +347,6 @@ namespace ranges __detail::__make_unsigned_like_t<iter_difference_t<_It>>) -> subrange<_It, _Sent, subrange_kind::sized>; - template<__detail::__iterator_sentinel_pair _Pr> - subrange(_Pr) - -> subrange<tuple_element_t<0, _Pr>, tuple_element_t<1, _Pr>>; - - template<__detail::__iterator_sentinel_pair _Pr> - subrange(_Pr, __detail::__make_unsigned_like_t<iter_difference_t< - tuple_element_t<0, _Pr>>>) - -> subrange<tuple_element_t<0, _Pr>, tuple_element_t<1, _Pr>, - subrange_kind::sized>; - template<borrowed_range _Rng> subrange(_Rng&&) -> subrange<iterator_t<_Rng>, sentinel_t<_Rng>, diff --git a/libstdc++-v3/testsuite/std/ranges/subrange/lwg3282_neg.cc b/libstdc++-v3/testsuite/std/ranges/subrange/lwg3282_neg.cc index d9894e4f137..170f4d2962b 100644 --- a/libstdc++-v3/testsuite/std/ranges/subrange/lwg3282_neg.cc +++ b/libstdc++-v3/testsuite/std/ranges/subrange/lwg3282_neg.cc @@ -29,3 +29,16 @@ struct Base {}; struct Derived : Base {}; subrange<Derived*> sd; subrange<Base*> sb = sd; // { dg-error "conversion" } + +void +test_lwg3404() +{ + // LWG 3404. Finish removing subrange's conversions from pair-like + std::pair<char*, char*> p; + subrange sb1(p); // { dg-error "no matching function" } + // { dg-error "class template argument deduction" "" { target *-*-* } 38 } + subrange sb2(p, p.second - p.first); // { dg-error "no matching function" } + // { dg-error "class template argument deduction" "" { target *-*-* } 40 } + + // { dg-prune-output "in requirements with" } +}