v4: when function argument name matches a local variable name, local variable is marked undefined

Try this snippit with Qt5.2 beta1, then compare with Qt5.0:

import QtQuick 2.0

MouseArea {
    width: 200
    height: 100

    QtObject {
        id: d
        function hello(input) {
            var temp = "Hello " + input;
            var input = temp + "!";
            print(input);
        }
    }

    onClicked: {
        d.hello("you")
    }
}

In 5.0, it prints "Hello you!" but in 5.2 it prints "Hello undefined!"

The fact that the function 'hello' names its argument the same as one of its local variables is naughty, but I suspect it should work. I'm no EMCAScript master however.