I have a fairly complex data model where the base ...

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[Mark]

I have a fairly complex data model where the base interface has a @Composable operator fun invoke(): String = … function. One of the sub interfaces is a fun interface and I was getting this runtime error whenever invoke() was called on an instance of that `fun interface`:

java.lang.AbstractMethodError: abstract method "java.lang.String BaseInterface.invoke(androidx.compose.runtime.Composer, int)"

Using a standard interface instead of a fun interface solved the problem. AI reckons:

The error occurred because the fun interface was trying to create a synthetic method that conflicted with the @Composable invoke() method from the parent interface. By making it a regular interface, we ensure proper inheritance of all methods from BaseInterface.

Is this a known issue? I can’t post the full data model here because it’s too much code, so I hope this is enough info.

[dmitriy.novozhilov]

cc @shikasd

[shikasd]

Can you file a bug to Google issue tracker? I think this is new

[Mark]

Not sure, but it might be the same as this runtime exception:

interface Foo {
    fun foo(): String = "foo"
}

fun interface Bar: Foo {
    operator fun invoke(): String
}

fun main() {
    val bar = Bar { "bar" }
    println("value: ${bar.foo()}") // "does not define or inherit an implementation of the resolved method 'abstract java.lang.String foo()'"
}

[shikasd]

Yeah, looks the same

[shikasd]

I am not sure how extending fun interfaces works tbh
Although the second one is a bug on Kotlin side

[Mark]

https://issuetracker.google.com/issues/422940457