Vector bool may not have to store a range of space optimized bool values but the interface is still different enough and guarantees different enough that is is

Vector bool may not have to store a range of space optimized bool values but the interface is still different enough and guarantees different enough that is is largely thought of as a mistake. For one the const reference type is bool and not bool const &. Plus other members like flip… mostly the issue is in generic code expecting a normal vector