K2/JSIR - `@JSExports` generates clashing declarat...

# k2-adopters

[andylamax]

K2/JSIR - @JSExports generates clashing declarations for companion objects that extends its own class

Kotlin: 2.0.0-Beta2
Work on: K1/Legacy
Issue: KT-64364

## Problem
When a companion object with a supper class whose clashing declarations have clearly being disambiguated with the @JsName
annotation, the compiler still errors with
JavaScript name (xxx) generated for this declaration clashes with another declarations

## Reproducer
Reproducer can be found at github

## Elaboration
Consider the following block of code

interface Optional<out T> {
  @JsName("valueOrThrowException")
  fun valueOrThrow(exp: Throwable): T

  fun valueOrThrow(): T = valueOrThrow(NoSuchElementException("Optional has no value"))
}

abstract class None<out T : Any> private constructor() : Optional<T> {
  @PublishedApi
  internal companion object : None<Nothing>()

  override fun valueOrThrow(exp: Throwable): Nothing = throw exp
}

This fails to compile with the error
• JavaScript name (valueOrThrow) generated for this declaration clashes with another declarations: [fun valueOrThrow(exp: Throwable): Nothing]
• JavaScript name (valueOrThrow) generated for this declaration clashes with another declarations: [fun valueOrThrow(): Nothing]
## Expected Behaviour
This should work the same as it does in Kotlin/JVM,Kotlin/Native or K1 for that matter, or without @JsExport
Workarounds
• Avoid using JsExports
• The compiler knows how to handle function overloads if the definitions haven't been marked by JsExport
• Avoid extending subclassing the class with it's companion object
• This problem appears to happen only when the companion object extends its own class

class None<out T : Any> private constructor() : Optional<T> {
    
  @PublishedApi
  internal companion object {
    val instance by lazy { None<Nothing>() }
  }

  override fun valueOrThrow(exp: Throwable): Nothing = throw exp
}