[dllthomas]

> [Performance cost] is (de facto) required for dynamically typed languages, but not for statically typed ones where the newtype constructor/deconstructor can be elided at compile time.

For a single value, it should reliably be free in any reasonable statically typed language that meet your other criteria.

For a collection, it may still be de facto required. Unwrapping a set of addresses into a set of strings takes unnecessary cycles, an unsafe coercion, sufficiently sophisticated affordances around coercion that it can be safe, or a smart enough optimiser. At least some static languages have at least one of these; I'm not sure all do, and certainly not all have always had.