[clang-tools-extra] [clang-tidy] Fix bugprone-tagged-union-member-count false-positive (PR #135831)

[Baranov Victor via cfe-commits]

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Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/135831 at github.com>


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@@ -28,6 +31,25 @@ Example:
     } Data;
   };
 
+The following example illustrates the exception for unions and enums from
+system header files and the ``std`` namespace.
+
+.. code-block:: c++
+
+  #include <pthread.h>
+
+  struct NotTaggedUnion {
+    enum MyEnum { MyEnumConstant1, MyEnumConstant2 } En;
+    pthread_mutex_t Mutex;
+  };
+
+The ``pthread_mutex_t`` type may be defined as a union behind a typedef,
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vbvictor wrote:

```suggestion
The ``pthread_mutex_t`` type may be defined as a union behind a ``typedef``,
```

https://github.com/llvm/llvm-project/pull/135831