What's the difference between `::` and `+:` for prepending to a list)?

Question

List has 2 methods that are specified to prepend an element to an (immutable) list:

• +: (implementing Seq.+:), and
<

Answer 1

+: is more generic, since it allows the result type to be different from the type of the object it is called on. For example:

scala> Range(1,4).+:(0)
res7: scala.collection.immutable.IndexedSeq[Int] = Vector(0, 1, 2, 3)