Scala's '::' operator, how does it work?

Question

In Scala, I can make a caseclass, case class Foo(x:Int), and then put it in a list like so:

List(Foo(42))

Now, nothing strange

Answer 1

It ends with a :. And that is the sign, that this function is defined in the class to the right (in List class here).

So, it's List(Foo(2)).::(Foo(40)), not Foo(40).::(List(Foo(2))) in your example.