I have an expect class: ```public expect class CopyOnWriteArrayList<E>() : MutableList<E&gt...

# k2-adopters

[Edoardo Luppi]

I have an expect class:

public expect class CopyOnWriteArrayList<E>() : MutableList<E> {
  public constructor(elements: Collection<E>)
  
  ... all the methods from MutableList. Not sure why but K2 requires overriding them explicitly
}

With an actual typealias per platform:

public actual typealias CopyOnWriteArrayList<E> = ArrayList<E> // Native
public actual typealias CopyOnWriteArrayList<E> = java.util.concurrent.CopyOnWriteArrayList<E> // JVM
public actual typealias CopyOnWriteArrayList<E> = ArrayList<E> // WASM WASI
public actual typealias CopyOnWriteArrayList<E> = ArrayList<E> // JS and WASM JS

K2 complains with this error:

e: file:///C:/Users/.../CopyOnWriteArrayList.kt:5:1 Expect declaration `CopyOnWriteArrayList` doesn't match actual `CopyOnWriteArrayList` because some expected members have no actual ones

But without telling me which expected members. Is this a bug?

[Edoardo Luppi]

Maybe it's https://youtrack.jetbrains.com/issue/KT-60155/?

[dmitriy.novozhilov]

cc @bobko, @Roman Efremov

[Roman Efremov]

@Edoardo Luppi could you tell please, which compiler version are you using (2.0.0-Beta3/earlier)? And on which platform it is reported (JVM/Native/other)?

[Edoardo Luppi]

@Roman Efremov forgot to try it with 2.0.0-Beta3. I'm using 1.9.22 with experimental K2 enabled.
Will let you know if it happens the same in the latest one.

The error is reported on the common source set btw.

[Edoardo Luppi]

Ahhh nice, with Beta3 I get a much better error message.

e: file:///C:/Users/edoardo.luppi/IdeaProjects/antlr-kotlin/antlr-kotlin-runtime/src/jvmMain/kotlin/com/strumenta/antlrkotlin/runtime/IdentityHashMap.kt:8:25 'actual typealias IdentityHashMap<K, V> = IdentityHashMap<K, V>' has no corresponding members for expected class members:

    expect val values: MutableCollection<V>

e: file:///C:/Users/edoardo.luppi/IdeaProjects/antlr-kotlin/antlr-kotlin-runtime/src/jvmMain/kotlin/com/strumenta/antlrkotlin/runtime/WeakHashMap.kt:8:25 'actual typealias WeakHashMap<K, V> = WeakHashMap<K, V>' has no corresponding members for expected class members:

    expect val values: MutableCollection<V>

[Edoardo Luppi]

I guess Kotlin is looking for a getValues() method, but the Java classes have values()

[Edoardo Luppi]

(Not sure if you consider it a bug or not tho)

[Roman Efremov]

This is known problem (KT-63624), should be fixed in 2.0.0-Beta4

[Roman Efremov]

Thanks for the report!

[Edoardo Luppi]

Oh nice, thanks!