override val isExtension: Boolean
        get() = withValidityAssertion { descriptor.isExtension }

    override val origin: KtSymbolOrigin
        get() = withValidityAssertion { expandedDescriptor.getSymbolOrigin(analysisContext) }

    override val typeParameters: List<KtTypeParameterSymbol>
        get() = withValidityAssertion { descriptor.typeParameters.map { KtFe10DescTypeParameterSymbol(it, analysisContext) } }