[pushed] c++: extend Wdangling-reference17.C [PR109642]

[Marek Polacek <polacek@redhat.com>]

Tested x86_64-pc-linux-gnu, applying to trunk.

-- >8 --
This patch extends g++.dg/warn/Wdangling-reference17.C with code
from PR109642.  I'm not creating a new test because this one
already #includes the required headers.

	PR c++/109642

gcc/testsuite/ChangeLog:

	* g++.dg/warn/Wdangling-reference17.C: Additional testing.
---
 gcc/testsuite/g++.dg/warn/Wdangling-reference17.C | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/gcc/testsuite/g++.dg/warn/Wdangling-reference17.C b/gcc/testsuite/g++.dg/warn/Wdangling-reference17.C
index 223698422c2..8cda5dea444 100644
--- a/gcc/testsuite/g++.dg/warn/Wdangling-reference17.C
+++ b/gcc/testsuite/g++.dg/warn/Wdangling-reference17.C
@@ -4,6 +4,7 @@
 
 #include <vector>
 #include <ranges>
+#include <span>
 
 int main()
 {
@@ -12,4 +13,15 @@ int main()
     {
       (void) i;
     }
+
+  // From c++/109642.
+  const auto vec = std::vector{ 1, 2, 3 };
+  const auto s = std::span<decltype(vec)::value_type const>{vec};
+
+  for ([[maybe_unused]] auto _ : s | std::views::take(2)) { }
+
+  for ([[maybe_unused]] auto _ : vec | std::views::take(2)) { }
+
+  const auto s_view = s | std::views::take(2);
+  for ([[maybe_unused]] auto _ : s_view) { }
 }

base-commit: bc77c035c45bb224790b1c03d06a64c8a1cc51c5
-- 
2.43.0