[throwaway894345]

Yes, I think in the general sense of “first-class X”, “first-class types” would refer to any language with a concept of “type” (except perhaps certain dynamic languages where types are built from language primitives, but I’m not so sure about that case). I’m inclined to say that “first-class types” overrides that general formulation to mean “reified types” specifically. It’s also possible that I’m mistaken and the general formulation of “first-class X” always means exactly “reified X” (although I think reflection is a form of reification, and thus Go would have “first-class types” despite your above distinction between first-class types and reflected types), in which case Go doesn’t have “first-class goroutines”.