CON50-CPP: Mutexes do not have destructors in most real libraries

Mark ~mutex() as deleted, as that is what we see in real libraries.

Also modify lock_guard. This didn't have any affect on the test, but retained
to ensure we better reflect real compilers.

Author: lcartey

cpp/common/test/includes/standard-library/mutex.h

@@ -23,7 +23,7 @@ constexpr try_to_lock_t try_to_lock{};
 class mutex {
 public:
   constexpr mutex() noexcept;
-  ~mutex();
+  ~mutex() = default;
   mutex(const mutex &) = delete;
   mutex &operator=(const mutex &) = delete;
   void lock();
@@ -62,15 +62,19 @@ template <class Mutex>
 void swap(unique_lock<Mutex> &x, unique_lock<Mutex> &y) noexcept;
 
 template <class _Lock0, class _Lock1, class... _LockN>
-void lock(_Lock0 &_Lk0, _Lock1 &_Lk1, _LockN &..._LkN) { }
+void lock(_Lock0 &_Lk0, _Lock1 &_Lk1, _LockN &..._LkN) {}
 
 template <typename Mutex> class lock_guard {
 public:
   typedef Mutex mutex_type;
 
-  explicit lock_guard(mutex_type &__m);
+  explicit lock_guard(mutex_type &__m) : _m(__m) { _m.lock(); }
   lock_guard(const lock_guard &) = delete;
   lock_guard &operator=(const lock_guard &) = delete;
+  ~lock_guard() { _m.unlock(); }
+
+private:
+  mutex_type &_m;
 };
 
 } // namespace std

cpp/common/test/rules/donotdestroyamutexwhileitislocked/DoNotDestroyAMutexWhileItIsLocked.expected

@@ -1,6 +1,3 @@
-| test.cpp:4:18:4:33 | call to mutex | Mutex used by thread potentially $@ while in use. | test.cpp:11:18:11:26 | call to ~mutex | destroyed |
 | test.cpp:4:18:4:33 | call to mutex | Mutex used by thread potentially $@ while in use. | test.cpp:11:18:11:26 | delete | destroyed |
-| test.cpp:16:14:16:15 | call to mutex | Mutex used by thread potentially $@ while in use. | test.cpp:21:1:21:1 | call to ~mutex | destroyed |
 | test.cpp:16:14:16:15 | call to mutex | Mutex used by thread potentially $@ while in use. | test.cpp:21:1:21:1 | return ... | destroyed |
-| test.cpp:94:8:94:23 | call to mutex | Mutex used by thread potentially $@ while in use. | test.cpp:10:34:10:42 | call to ~mutex | destroyed |
 | test.cpp:94:8:94:23 | call to mutex | Mutex used by thread potentially $@ while in use. | test.cpp:10:34:10:42 | delete | destroyed |