benchmarks: fix some (future) -Wunused-result warnings

Clang 10 warns about unused results of relational operators, which is
where this is coming from.

Fix by adding the usual prefix

  [[maybe_unused]] auto r = ~~~;

to silence the warning. Do this elsewhere, too, since [[nodiscard]] is
slowly being rolled out across all our APIs. This is not a complete
sweep, though.

Not picking to 5.15, because this pattern doesn't work there and I
don't want to introduce a new one.

Pick-to: 6.3 6.2
Change-Id: I40dd8ad07496b686979dce533e044cbb486e30f3
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/benchmarks/corelib/io/qurl/tst_bench_qurl.cpp b/tests/benchmarks/corelib/io/qurl/tst_bench_qurl.cpp
index 8165f8d059..0ed155d221 100644
--- a/tests/benchmarks/corelib/io/qurl/tst_bench_qurl.cpp
+++ b/tests/benchmarks/corelib/io/qurl/tst_bench_qurl.cpp
@@ -188,7 +188,7 @@ void tst_QUrl::equality()
         QUrl url("pics/avatar.png");
         QUrl url2("pics/avatar2.png");
         QBENCHMARK {
-            url == url2;
+            [[maybe_unused]] auto r = url == url2;
         }
     }
 }