[gcc r14-8339] c++: extend Wdangling-reference17.C [PR109642]

[gcc r14-8339] c++: extend Wdangling-reference17.C [PR109642]

[Marek Polacek]

https://gcc.gnu.org/g:c596ce03120cc22e141186401c6656009ddebdaa

commit r14-8339-gc596ce03120cc22e141186401c6656009ddebdaa
Author: Marek Polacek <polacek@redhat.com>
Date:   Mon Jan 22 16:12:33 2024 -0500

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

Diff:
---
 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) { }
 }