diff mbox series

[pushed] libstdc++: Make ranges::to closure objects SFINAE-friendly [PR112802]

Message ID 20231218230631.1779040-1-ppalka@redhat.com
State New
Headers show
Series [pushed] libstdc++: Make ranges::to closure objects SFINAE-friendly [PR112802] | expand

Commit Message

Patrick Palka Dec. 18, 2023, 11:06 p.m. UTC 
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(+)
diff mbox series

Patch

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index be8475c0cb1..752a04e01bd 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -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
 	{
diff --git a/libstdc++-v3/testsuite/std/ranges/conv/1.cc b/libstdc++-v3/testsuite/std/ranges/conv/1.cc
index 6d6a708ab64..09fd515edf1 100644
--- a/libstdc++-v3/testsuite/std/ranges/conv/1.cc
+++ b/libstdc++-v3/testsuite/std/ranges/conv/1.cc
@@ -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();
 }