As part of implementing K2 support in a compiler plugin that generates a

Companion

object I get the following error when combining the plugin with

kotlinx.serialization

.

java.lang.IllegalStateException: Multiple plugins generated nested class with same name Companion for class /Sample:
public final companion object Companion : R|kotlin/Any| {
}

public final companion object Companion : R|kotlin/Any| {
}

Seems like both plugins are generating a

Companion

. For user-defined companions the

FirRegularClassSymbol.companionObjectSymbol

will be non-null, but I have tried debugging and cannot find any information to indentify and prevent this situation in my

FirDeclarationGenerationExtension.getNestedClassifiersNames

and/or

FirDeclarationGenerationExtension.generateNestedClassLikeDeclaration

. Also tried debugging the

kotlinx.serialization

-plugin and there is also no visibility of my generated companion, so does not look like an ordering issue and even with both plugins setting their appropriate

GeneratedDeclarationKey

there is no way to detect each others additions. Anybody with a suggestion to identify this situation, or how are plugins supposed to coexist?

Hey Such plugins interaction actually just want considered when API was designed Could you please report an issue?

I have created this youtrack issue

Thank you!