Remove unused LockAssertion struct

doc/developer-notes.md

@@ -793,25 +793,6 @@ bool ChainstateManager::ProcessNewBlock(...)
 }
 ```
 
-- When Clang Thread Safety Analysis is unable to determine if a mutex is locked, use `LockAssertion` class instances:
-
-```C++
-// net_processing.h
-void RelayTransaction(...) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
-
-// net_processing.cpp
-void RelayTransaction(...)
-{
-    AssertLockHeld(::cs_main);
-
-    connman.ForEachNode([&txid, &wtxid](CNode* pnode) {
-        LockAssertion lock(::cs_main);
-        ...
-    });
-}
-
-```
-
 - Build and run tests with `-DDEBUG_LOCKORDER` to verify that no potential
   deadlocks are introduced. As of 0.12, this is defined by default when
   configuring with `--enable-debug`.

src/sync.h

@@ -352,18 +352,4 @@ public:
     }
 };
 
-// Utility class for indicating to compiler thread analysis that a mutex is
-// locked (when it couldn't be determined otherwise).
-struct SCOPED_LOCKABLE LockAssertion
-{
-    template <typename Mutex>
-    explicit LockAssertion(Mutex& mutex) EXCLUSIVE_LOCK_FUNCTION(mutex)
-    {
-#ifdef DEBUG_LOCKORDER
-        AssertLockHeld(mutex);
-#endif
-    }
-    ~LockAssertion() UNLOCK_FUNCTION() {}
-};
-
 #endif // BITCOIN_SYNC_H