[pushed] libstdc++: Make ranges::to closure objects SFINAE-friendly [PR112802]
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Commit Message
This also happens to fix composition of these closure objects.
PR libstdc++/112802
PR libstdc++/113068
libstdc++-v3/ChangeLog:
* include/std/ranges (__detail::_To::operator()): Add constraints.
(__detail::_To2::operator()): Likewise.
* testsuite/std/ranges/conv/1.cc (test_sfinae): New test.
(test_composition): New test.
---
libstdc++-v3/include/std/ranges | 4 ++++
libstdc++-v3/testsuite/std/ranges/conv/1.cc | 20 ++++++++++++++++++++
2 files changed, 24 insertions(+)
@@ -9389,6 +9389,8 @@ namespace __detail
struct _To
{
template<typename _Range, typename... _Args>
+ requires requires { ranges::to<_Cont>(std::declval<_Range>(),
+ std::declval<_Args>()...); }
constexpr auto
operator()(_Range&& __r, _Args&&... __args) const
{
@@ -9431,6 +9433,8 @@ namespace __detail
struct _To2
{
template<typename _Range, typename... _Args>
+ requires requires { ranges::to<_Cont>(std::declval<_Range>(),
+ std::declval<_Args>()...); }
constexpr auto
operator()(_Range&& __r, _Args&&... __args) const
{
@@ -448,6 +448,24 @@ test_constexpr()
static_assert(x == 6);
}
+void
+test_sfinae()
+{
+ // PR libstdc++/112802
+ [](auto x) {
+ static_assert(!requires { std::ranges::to<std::vector<int>>()(x); });
+ static_assert(!requires { std::ranges::to<std::vector>()(x); });
+ }(0);
+}
+
+void
+test_composition()
+{
+ // PR libstdc++/113068
+ auto adaptor = std::ranges::to<std::string>() | std::ranges::to<std::string>();
+ auto str = adaptor(" ");
+}
+
int main()
{
test_p1206r7_examples();
@@ -460,4 +478,6 @@ int main()
test_lwg3984();
test_nodiscard();
test_constexpr();
+ test_sfinae();
+ test_composition();
}