They may be in the current implementations, but removing an implementation constraint can only increase the solution space, so it cannot make the best implementation slower.
As a trivial example, the current implementation that guarantees iteration happens in insertion order also is a valid implementation for a spec that does not require that guarantee.
They may be in the current implementations, but removing an implementation constraint can only increase the solution space, so it cannot make the best implementation slower.
As a trivial example, the current implementation that guarantees iteration happens in insertion order also is a valid implementation for a spec that does not require that guarantee.