diff --git a/clang/docs/ThreadSafetyAnalysis.rst b/clang/docs/ThreadSafetyAnalysis.rst
--- a/clang/docs/ThreadSafetyAnalysis.rst
+++ b/clang/docs/ThreadSafetyAnalysis.rst
@@ -640,8 +640,8 @@
     Mutex mu;
 
   public:
-    // For thread safety analysis only.  Does not actually return mu.
-    Mutex* getMu() RETURN_CAPABILITY(mu) { return 0; }
+    // For thread safety analysis only.  Does not need to be defined.
+    Mutex* getMu() RETURN_CAPABILITY(mu);
 
     void doSomething() REQUIRES(mu);
   };