[libcxx-commits] [libcxx] [libc++] Add [[gnu::warn_unused]] to a bunch of threading utilities (PR #213963)

[Louis Dionne via libcxx-commits]

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@@ -69,3 +77,48 @@ void container_const_iterators() {
   std::vector<int>::const_iterator m;                  // expected-warning {{unused variable}}
   std::vector<bool>::const_iterator n;                 // expected-warning {{unused variable}}
 }
+
+#ifndef TEST_HAS_NO_THREADS
+void synchronization(std::mutex& m) {
+  // <mutex>
+  std::mutex a;                      // expected-warning {{unused variable}}
+  std::once_flag b;                  // expected-warning {{unused variable}}
+  std::recursive_mutex c;            // expected-warning {{unused variable}}
+  std::recursive_timed_mutex d;      // expected-warning {{unused variable}}
+  std::timed_mutex e;                // expected-warning {{unused variable}}
+  std::unique_lock<std::mutex> f;    // TODO: We should warn on this
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ldionne wrote:

Let's link to a Github issue instead (same below).

https://github.com/llvm/llvm-project/pull/213963