Exactly because of this reason.
value :: is not a member of Int
In Scala, the operators are actually functions on objects. In this case, :: is a function on Nil object, which is actually an Empty list object.
scala> Nil
res0: scala.collection.immutable.Nil.type = List()
When you do 1::2, Scala looks for the function named :: on 2 and it doesn't find that. That is why it fails with that error.
Note: In Scala, if the last character of the operator is not colon, then the operator is invoked on the first operand. For example, 1 + 2 is basically 1.+(2). But, if the last character is colon, the the operator is invoked on the right hand side operand. So in this case, 1 :: Nil is actually Nil.::(1). Since, the :: returns another list object, you can chain it, like this 1 :: 2 :: Nil is actually, Nil.::(2).::(1).
