Исправление invy, (текущая версия) :
If T is a union type, the first non-static named data member is zero-initialized and all padding is initialized to zero bits.
Ну и работало оно на x86 навернре у как раз пару полей без конструктора инициализировало.
На x64 ..uh oh.
Исходная версия invy, :
If T is a union type, the first non-static named data member is zero-initialized and all padding is initialized to zero bits.