Issue with ReplaceWith and this

Support
1

So I have an issue with deprecating extension function. I think it is easiest to explain it on example so let’s say we have these two extension functions (it’s a stupid example but it serves just to show where the issue is).

@Deprecated("message", ReplaceWith("save(MyClass(this), foo, bar)"))
ClassFromLib.saveOld(foo: String, bar: String)

ClassFromLib.save(myClass: MyClass, foo: String, bar: String)

Where my class is something like this:

class MyClass(param: BaseClass)

So the usage for those extension methods would be:

class CallerClass(val libClass: ClassFormLib): BaseClass {
    fun someFun() {
        libClass.saveOld("foo", "bar")
        
        libClass.save(MyClass(this), "foo", "bar")
    }
}

And when in Android Studio I try to replace call of saveOld function I actually get something like this:

libClass.save(MyClass(libClass), "foo", "bar")

And that is a type mismatch because required is BaseClass but it got ClassFormLib, what I really wanted was that I literally get this not instance on which that extension function is called. I understand that this is expected behaviour and it works as it should - this is detected and it presumes that it reffers to instance of class on which it is called, but I just want literally this to be there. Is that possible in any way?

I have a stupid workaround for that, I wrote deprecation like this:

@Deprecated("message", ReplaceWith("save(MyClass(thi), foo, bar)"))
ClassFromLib.saveOld(foo: String, bar: String)

But that just stupid because than somebody who uses that need to manually add s.

2

No idea if this is possible. Just out of interest what happens if you don’t have a BaseClass as a reciever, eg.

fun someGenericFunction(libClass: ClassFromLib) {
    libClass.saveOld("foo", "bar")
}

Based on what I see you would want to replace that with

fun someGenericFunction(libClass: ClassFromLib) {
    libClass.save(MyClass(this), "foo", "bar")
}

but there is no this so it would result in a compiler error.
Or did I understand your problem wrong?

1 Like
3

Sorry I realised that I had one error in original post. But I edited it and fixed that issue. It might be that it confused you. I don’t understand what exactly you mean by “what happens”. In my case those methods are always called inside some class which inherits BaseClass. And in your case, yes I want it to be like you wrote it but actually what I will get is this:

fun someGenericFunction(libClass: ClassFromLib) {
    libClass.save(MyClass(libClass), "foo", "bar")
}

Because deprecation rule will recognize keyword this and it will replace this with the object on which that method is called so in this case libClass. But I wanted it to just put MyClass(this) as first param.