Sometimes tools can be overly pedantic

I received a mail from a reader of Effective C# asking about a possible error in one of my samples.  He pointed out that my example for the Dispose pattern (Item 17) triggers an FX Cop (MS Code Analysis) warning:

// Have its own disposed flag.
private bool disposed = false;

protected override void Dispose(bool isDisposing)
{
 // Don't dispose more than once.
 if (disposed)
 return;
 if (isDisposing)
 {
 // TODO: free managed resources here.
 }
 // TODO: free unmanaged resources here.

 // Let the base class free its resources.
 // Base class is responsible for calling
 // GC.SuppressFinalize( )
 base.Dispose(isDisposing);

 // Set derived class disposed flag:
 disposed = true;
}

The warning says this code does not ensure that base.Dispose() is always called.  I suppose if you examined the entire class, and somewhere else a piece of code sets the disposed flag to true, it’s possible. But that seems to be a very unlikely occurrence.

The lesson (to me) is that the tools are there to help us, not control us.