UserModel.Creator(
_, foo, bar, cat, moo, _ -> User(foo, bar, cat, moo)
)

works fine, but

UserModel.Creator(
_, foo, bar, cat, moo, _ -> {
Log.d("")
User(foo, bar, cat, moo)
}
)

doesn’t work.

i believe that happens because when you add the closure brackets the compiler detects it as a function returning Unit

well, from the error log I posted earlier, it seems to the the result is

((Long, String, String, String, String, String?) -> () -> User)

What if you specify

UserModel.Creator<() -> User>(...)

?

Unfortunately, that doesn’t work since the expected type from the root factory object is

User

Needs to be

UserModel.Creator( {
_, foo, bar, cat, moo, _ ->
Log.d("")
User(foo, bar, cat, moo)
}
)

thanks, I guess I don’t fully understand the consequences of wrapping code in a closure

Ah, I see. In that case do what @mwerschy says. (EDIT: you already did 🙂)