[Bug] Random warnings for unresolved `java.io.Serializable` from commonMain

[juliamcclellan]

What is happening? What should have happened instead?

I'm seeing a number of lines logged with WARN: `java.io.Serializable` is unresolved in [some location] for seemingly random lines in the commonMain source set (there is no direct reference to java.io.Serializable). This is for a KMP project with at least one js or native target in addition to a jvm target.

This happens starting with 2.3.0-dev-426.

Reproducer

Some example lines which trigger the warning:

typealias LongType = Long
enum class CommonEnum
expect class FooException : Exception

Dokka version

2.3.0-dev-426

Kotlin Gradle Plugin (KGP) version

No response

Android Gradle Plugin (AGP) version (if applicable)

No response

Build tool

Gradle

Project type

• Kotlin Multiplatform (KMP)
• Android
• JVM
• Other

Anything else? (optional)

No response

[whyoleg]

I believe it might be coming from an "implicit" supertype, which is added to Throwable, primitives, and probably enums.
AFAIK, a similar situation could happen with Cloneable, and I've seen "unresolved" references to those in IDEA at some point. Might be similar to KT-74448 K2. False positive MISSING_DEPENDENCY_SUPERCLASS in LinkedListTest.kt, kotlinx.coroutines.

Not sure if it's an issue in AA or in Dokka at this point. cc @vmishenev, might be worth asking the AA team.