`Fault` keyword in try block

Question

While exploring an assembly in reflector I stumbled upon a fault keyword in a compiler generated class.

Do any of you know the meaning if this keyword?

C#

private bool MoveNext()
{
    bool flag;
    try
    {
        // [...]
    }
    fault
    {
        this.Dispose();
    }
    return flag;
}

vb.net

Private Function MoveNext() As Boolean 
    Dim flag As Boolean
    Try 
        ' [...]
    Fault
        Me.Dispose
    End Try
    Return flag
End Function

Answer 1

Do any of you know the meaning if this keyword?

Yes. It's not valid C#, but in IL it's the equivalent of finally, but only if an exception has been thrown.

There's no direct correlation in C#, which is why the decompiler can't decompile it to proper C#. You could emulate it with something like:

bool success = false;
try
{
    ... stuff ...
    success = true; // This has to occur on all "normal" ways of exiting the
                    // block, including return statements.
}
finally
{
    if (!success)
    {
        Dispose();
    }
}

I mention it in my iterator block implementation details article which looks relevant to your particular example :)