override val element: KtThisExpression,
) : ElementToShorten() {
    override val nameToImport: FqName? = null
    override val importAllInParent: Boolean = false
}

/**
 * N.B. Does not subclass [ElementToShorten] because currently
 * there's no reason to do that.
 */
private class ShortenKDocQualifier(
    val element: KDocName,
)

        require(subClass is KtFirSymbol<*>)
        require(superClass is KtFirSymbol<*>)

        if (subClass == superClass) return false
        return isSubClassOf(
            subClass = subClass.firSymbol.fir as FirClass,
            superClass = superClass.firSymbol.fir as FirClass,
            rootModuleSession,

            token,
        )
    }
    add(FirErrors.SUBCLASS_OPT_IN_INAPPLICABLE) { firDiagnostic ->
        SubclassOptInInapplicableImpl(
            firDiagnostic.a,
            firDiagnostic as KtPsiDiagnostic,
            token,
        )
    }
    add(FirErrors.SUBCLASS_OPT_ARGUMENT_IS_NOT_MARKER) { firDiagnostic ->
        SubclassOptArgumentIsNotMarkerImpl(

- [`KTIJ-26576`](https://youtrack.jetbrains.com/issue/KTIJ-26576) K2 IDE: "Redundant qualifier" false positive with referring parent's subclass in type constraint
- [`KTIJ-26785`](https://youtrack.jetbrains.com/issue/KTIJ-26785) K2 IDE: False positive "Redundant qualifier" inspection in extension function for Java interface with nested interface

        }

        return overriddenDescriptors
    }

    override fun isSubClassOf(subClass: KtClassOrObjectSymbol, superClass: KtClassOrObjectSymbol): Boolean {
        if (subClass == superClass) return false

        val subClassDescriptor = getSymbolDescriptor(subClass) as? ClassDescriptor ?: return false
        val superClassDescriptor = getSymbolDescriptor(superClass) as? ClassDescriptor ?: return false

) : KtSubstitutorProvider(), KtFirAnalysisSessionComponent {
    override fun createSubstitutor(
        subClass: KtClassOrObjectSymbol,
        superClass: KtClassOrObjectSymbol,
    ): KtSubstitutor? {
        if (subClass == superClass) return KtSubstitutor.Empty(token)

        val baseFirSymbol = subClass.firSymbol
        val superFirSymbol = superClass.firSymbol

             * no separate symbol for that case.
             *
             * Java statics present a similar case - they can be imported not only from the declaring class,
             * but also from any subclass.
             */
            private fun FirQualifiedAccessExpression.importableNameForImplicitlyDispatchedCallable(): FqName? {
                val dispatchReceiver = dispatchReceiver
                if (