what would be the underlying difference between

val self = this

and

val self get() = this

is the latter more expensive for no reason? are they the same?

The latter doesn't create a member field.

ergo you can use it in things like interfaces, but are there other advantages? does it have no disadvantages?

Less memory? Can be inlined?

Keep in mind that the second one evaluates the expression every time, the first one only once. No different in this exact case though.

Ah, wasn't thinking about the general case.