How to convert/cast from a protocol to a class in swift?

Pretty simple, I'd have thought; I just want to check if a variable is a class and cast it to one if possible.

For example:

var cellProtocol:MyTableViewCellProtocol? = nil
cellProtocol = tableView.dequeueReusableCellWithIdentifier(kCellIdentifier, forIndexPath: indexPath) as MyTableViewCell

how do I explicitly cast the cell to a UITableViewCell?

Inheritance as follows:

class MyTableViewCell: UITableViewCell, MyTableViewCellProtocol {
//....
}


@objc protocol MyTableViewCellProtocol: class, NSObjectProtocol {
    func configureCell()
}

That protocol definition was the result of me trying to solve this problem. My original one didn't have the @objc tag in it or the class-only identifier.

I tried a few things to make the cast happen but it has not worked:

    var cellToReturn = cellProtocol as UITableViewCell

This doesn't compile because UITableViewCell does not inherit explicitly from MyTableViewCellProtocol.

    var cellToReturn = cellProtocol as AnyObject as UITableViewCell

This fails at runtime because cellProtocol fails to cast into AnyObject.

I haven't been able to get the unsafeBitCast thing to work yet but that's another possibility I've been exploring.

Just a note, that this DOES work in Obj-C.

id<MyTableViewCellProtocol> cellProtocol = cell;
[cellProtocol configureCell];
UITableViewCell *cellCast = (UITableViewCell *)cellProtocol;

This gives me no errors and runs fine.