) : KtSubstitutorFactory(), KtFirAnalysisSessionComponent {

    override fun buildSubstitutor(builder: KtSubstitutorBuilder): KtSubstitutor {
        if (builder.mappings.isEmpty()) return KtSubstitutor.Empty(token)

        val firSubstitution = buildMap {
            builder.mappings.forEach { (ktTypeParameterSymbol, ktType) ->
                check(ktTypeParameterSymbol is KtFirTypeParameterSymbol)
                check(ktType is KtFirType)