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>

1 files changed, 1 insertions, 0 deletions

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 c9e9112..890fdf8 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" }