scala, guidelines on return type - when prefer seq, iterable, traversable

Question

When do you choose to type a given function\'s return type as Seq vs Iterable vs Traversable (or alternatively even deeper within Se

Answer 1

Make your method's return type as specific as possible. Then if the caller wants to keep it as a SuperSpecializedHashMap or type it as a GenTraversableOnce, they can. This is why the compiler infers the most specific type by default.