Fix coverity CID 611220: unchecked dynamic_cast

[noryb009]

For GCI2013 task: ​https://www.google-melange.com/gci/task/view/google/gci2013/5785682865815552

[anevilyak]

This is a case where Coverity is technically correct, but not practically. The check for TYPE_ENUMERATION already accomplishes the same thing.

[noryb009]

Shouldn't it be changed to use `static_cast' instead, then?

[anevilyak]

Not necessarily, bear in mind dynamic_cast isn't only for checking type validity ; depending on the structure of the classes in question and the inheritance hierarchy involved, it may also adjust the 'this' pointer in the process, so it's not interchangeable with static_cast except in simple cases.

[noryb009]

Ok, thank you for the explanation!