override fun substitute(substitutor: KtSubstitutor): KtFunctionLikeSignature<S> = withValidityAssertion {
        KtFe10FunctionLikeSignature(
            symbol,
            substitutor.substitute(returnType),
            receiverType?.let { substitutor.substitute(it) },
            valueParameters.map { valueParameter ->

    override fun substitute(substitutor: KtSubstitutor): KtVariableLikeSignature<S> = withValidityAssertion {
        KtFe10VariableLikeSignature(
            symbol,
            substitutor.substitute(returnType),
            receiverType?.let { substitutor.substitute(it) },
        )
    }

    override fun equals(other: Any?): Boolean {

        var isImplicitInvoke = false

        // TODO: Ideally, we should get the substitutor from the candidate. But it seems there is no way to get the substitutor from the
        //  candidate, `Candidate.substitutor` is not complete. maybe we can carry over the final substitutor if it's available from
        //  body resolve phase?
        val substitutor = when (fir) {

        }

        fun buildSubstitutor(substitutor: ConeSubstitutor): KtSubstitutor {
            if (substitutor == ConeSubstitutor.Empty) return KtSubstitutor.Empty(token)
            return when (substitutor) {
                is ConeSubstitutorByMap -> KtFirMapBackedSubstitutor(substitutor, this@KtSymbolByFirBuilder)
                is ChainedSubstitutor -> KtFirChainedSubstitutor(substitutor, this@KtSymbolByFirBuilder)

                    return ApplicableAsFunctionalVariableCall(substitutor, receiverCastRequired, token)
                }

                return ApplicableAsExtensionCallable(substitutor, receiverCastRequired, token)
            }

            return implicitReceivers.firstNotNullOfOrNull(::processReceiver)
                ?: processReceiver(null)

/compiler/testData/versionRequirement/ "Kotlin JVM"
/compiler/testData/writeFlags/ "Kotlin JVM"
/compiler/testData/writeSignature/ "Kotlin JVM"
/compiler/testData/type-checker-test.kt "Kotlin Compiler Core"
/compiler/testData/type-substitutor.kt "Kotlin Compiler Core"
/compiler/tests/ "Kotlin Compiler Core" "Kotlin JVM" "Kotlin Native" "Kotlin Wasm" "Kotlin Common Backend"
/compiler/tests/org/jetbrains/kotlin/klib/ "Kotlin Common Backend"

    }

    override fun getEnhancedType(type: KtType): KtType? {
        require(type is KtFirType)
        val coneType = type.coneType
        val substitutor = EnhancedForWarningConeSubstitutor(typeContext)
        val enhancedConeType = substitutor.substituteType(coneType)

        return enhancedConeType?.asKtType()
    }

    override fun buildSelfClassType(symbol: KtNamedClassOrObjectSymbol): KtType {

- [`KT-59667`](https://youtrack.jetbrains.com/issue/KT-59667) Analysis API: PsiInvalidElementAccessException from JavaClassifierTypeImpl.substitutor
- [`KT-59705`](https://youtrack.jetbrains.com/issue/KT-59705) KotlinExceptionWithAttachments: No fir element was found for getter

            if (type.hasRecursiveTypeArgument()) return type
            // Return `null` means we will use [fir.resolve.substitution.Substitutors]'s [substituteRecursive]
            // that literally substitutes type arguments recursively.
            return null
        }

        val firClassNode = type.lookupTag.toSymbol(session) as? FirClassSymbol
        if (firClassNode != null) {

        val substitutor = (this as? FirQualifiedAccessExpression)
            ?.createConeSubstitutorFromTypeArguments(rootModuleSession, discardErrorTypes = !substituteWithErrorTypes)
            ?: ConeSubstitutor.Empty

        return resolvedArgumentMapping?.mapValuesTo(LinkedHashMap()) { (_, parameter) ->
            SubstitutedValueParameter(parameter, substitutor.substituteOrSelf(parameter.returnTypeRef.coneType))