[gcc r16-2104] libstdc++: Silence a warning in a test for span.

[Tomasz Kaminski]

https://gcc.gnu.org/g:a543fcbb72f014f146f5804c963bb9dfd936e50b

commit r16-2104-ga543fcbb72f014f146f5804c963bb9dfd936e50b
Author: Luc Grosheintz <luc.grosheintz@gmail.com>
Date:   Tue Jul 8 11:49:20 2025 +0200

    libstdc++: Silence a warning in a test for span.
    
    In a test of span, there's an unused variable myspan. This
    commit silences the warning.
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/23_containers/span/contiguous_range_neg.cc: Silence
            warning about unused variable myspan.
    
    Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
    Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
    Signed-off-by: Luc Grosheintz <luc.grosheintz@gmail.com>

Diff:
---
 libstdc++-v3/testsuite/23_containers/span/contiguous_range_neg.cc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libstdc++-v3/testsuite/23_containers/span/contiguous_range_neg.cc b/libstdc++-v3/testsuite/23_containers/span/contiguous_range_neg.cc
index c9e9112ed6dc..890fdf8aea08 100644
--- a/libstdc++-v3/testsuite/23_containers/span/contiguous_range_neg.cc
+++ b/libstdc++-v3/testsuite/23_containers/span/contiguous_range_neg.cc
@@ -25,6 +25,7 @@ main()
 {
   std::deque<int> d{};
   std::span<int, std::dynamic_extent> myspan(d); // { dg-error "no match" }
+  (void) myspan;
 }
 
 // { dg-prune-output "data" }