Not really, no. You can get localised unification but bidir as a whole like in Rust but you lose most of the advantage of unification. Hybrid systems are bidir for parts, unification for others.
But, I maintain that what the article calls HM is trully unification independantly of what's above. This is not about algorithm W. It's actually about the tension between solving types as a large constraint problem or using annotations to check.
But, I maintain that what the article calls HM is trully unification independantly of what's above. This is not about algorithm W. It's actually about the tension between solving types as a large constraint problem or using annotations to check.