It really depends on the semantics of those annotations. For example: how is v:Array.<int> enforced (and is it enforced at all)? Type annotations can be a goo

It really depends on the semantics of those annotations. For example: how is v:Array.<int> enforced (and is it enforced at all)? Type annotations can be a good to seed type inference analysis or adjust collected type feedback. But unless they guarantee stability of objects shapes (e.g. Array.<float> can contain only floating point numbers) they'll give little.