Reference to multiple bounds generic receiver extension function in Kotlin

Question

Has an extension function

fun <T> T.doSomething() where T: A, T: B

If there only one generic bound A, I can use syntax (A::doSomething)(instanceOfA) to reference to the function, but how to do this with multiple bounds?

Example:

interface A, interface B, and a extension function bounded with both interfaces fun <T> T.doSomething() where T: A, T: B.

Now I manage to "override" doSomething if a class extends additional interface C, like class X: A, B, C:

Declare another extension function fun <T> T.doSomething() where T: A, T: B, T: C
Declare doSomething() inside class X

If I use doSomething() in both "override" function directly will cause endless recursion. How can I reference to original fun <T> T.doSomething() where T: A, T: B(like super.doSomething())?

pls give a clear example of what you want to achieve. where do A and B come from? — Willi Mentzel, Jan 24 '19 at 22:48

score 1 · Accepted Answer · answered Jan 25 '19 at 07:39

A bit ugly, but

fun <T> T.doSomething() where T: A, T: B = ...

// calls the first version of doSomething
fun <T> T.doSomethingHelper() where T: A, T: B = this.doSomething()

@JvmName("doSomethingElse")
fun <T> T.doSomething() where T: A, T: B, T: C = ... // use doSomethingHelper() here

Without @JvmName I get

java.lang.ClassFormatError: Duplicate method name&signature in class file Simplest_versionKt

Reference to multiple bounds generic receiver extension function in Kotlin

1 Answers1