[FIR] add support for implementation by delgation

This commit handles "subclass: super-interface by delegate-expression".

During Psi2Fir, for each delegate, we add to the subclass a synthetic
field (which has type super-interface), and an assignment of the
delegate-expression to the synthetic field in the primary constructor,
so that the delegate-expression can be resolved and transformed along
the way.

During Fir2Ir, we look up delegatable members from the super-interface
and generate corresponding functions/properties for the subclass.

TODO: support for generic delegatable members and generic
super-interface.

compiler/fir/analysis-tests/testData/resolve/delegatedSuperType.txt

@@ -13,8 +13,11 @@ FILE: delegatedSuperType.kt
 
     }
     public final class C : R|A| {
+        local final field $$delegate_0: R|A|
+
         public constructor(b: R|B|): R|C| {
             super<R|kotlin/Any|>()
+            this@R|/C|.R|<local>/$$delegate_0| = R|<local>/b|
         }
 
         public final val b: R|B| = R|<local>/b|

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt

@@ -407,6 +407,10 @@ fun isOverriding(
             // Not checking the field type (they should match each other if everything other match, otherwise it's a compilation error)
             target.name == superCandidate.name
         }
+        target is IrProperty && superCandidate is IrProperty -> {
+            // Not checking the property type (they should match each other if names match, otherwise it's a compilation error)
+            target.name == superCandidate.name
+        }
         else -> false
     }
 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt

@@ -5,7 +5,10 @@
 
 package org.jetbrains.kotlin.fir.backend
 
-import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.descriptors.ClassKind
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.descriptors.Visibilities
+import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.lazy.Fir2IrLazyClass
 import org.jetbrains.kotlin.fir.resolve.firProvider
@@ -23,7 +26,10 @@ import org.jetbrains.kotlin.ir.declarations.impl.IrClassImpl
 import org.jetbrains.kotlin.ir.declarations.impl.IrEnumEntryImpl
 import org.jetbrains.kotlin.ir.declarations.impl.IrTypeAliasImpl
 import org.jetbrains.kotlin.ir.declarations.impl.IrTypeParameterImpl
-import org.jetbrains.kotlin.ir.descriptors.*
+import org.jetbrains.kotlin.ir.descriptors.WrappedClassDescriptor
+import org.jetbrains.kotlin.ir.descriptors.WrappedEnumEntryDescriptor
+import org.jetbrains.kotlin.ir.descriptors.WrappedTypeAliasDescriptor
+import org.jetbrains.kotlin.ir.descriptors.WrappedTypeParameterDescriptor
 import org.jetbrains.kotlin.ir.expressions.impl.IrEnumConstructorCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrExpressionBodyImpl
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConverter.kt

@@ -87,7 +87,7 @@ class Fir2IrConverter(
         anonymousObject.getPrimaryConstructorIfAny()?.let {
             irClass.declarations += declarationStorage.createIrConstructor(it, irClass)
         }
-        for (declaration in anonymousObject.declarations) {
+        for (declaration in sortBySynthetic(anonymousObject.declarations)) {
             if (declaration is FirRegularClass) {
                 registerClassAndNestedClasses(declaration, irClass)
                 processClassAndNestedClassHeaders(declaration)
@@ -98,6 +98,13 @@ class Fir2IrConverter(
         return irClass
     }
 
+    // Sort declarations so that all non-synthetic declarations are before synthetic ones.
+    // This is needed because converting synthetic fields for implementation delegation needs to know
+    // existing declarations in the class to avoid adding redundant delegated members.
+    private fun sortBySynthetic(declarations: List<FirDeclaration>) : Iterable<FirDeclaration> {
+        return declarations.sortedBy { it.isSynthetic }
+    }
+
     private fun processClassMembers(
         regularClass: FirRegularClass,
         irClass: IrClass = classifierStorage.getCachedIrClass(regularClass)!!
@@ -105,7 +112,7 @@ class Fir2IrConverter(
         regularClass.getPrimaryConstructorIfAny()?.let {
             irClass.declarations += declarationStorage.createIrConstructor(it, irClass)
         }
-        for (declaration in regularClass.declarations) {
+        for (declaration in sortBySynthetic(regularClass.declarations)) {
             val irDeclaration = processMemberDeclaration(declaration, irClass) ?: continue
             irClass.declarations += irDeclaration
         }
@@ -142,6 +149,13 @@ class Fir2IrConverter(
             is FirProperty -> {
                 declarationStorage.createIrProperty(declaration, parent)
             }
+            is FirField -> {
+                if (declaration.isSynthetic) {
+                    declarationStorage.createIrFieldAndDelegatedMembers(declaration, parent as IrClass)
+                } else {
+                    throw AssertionError("Unexpected non-synthetic field: ${declaration::class}")
+                }
+            }
             is FirConstructor -> if (!declaration.isPrimary) {
                 declarationStorage.createIrConstructor(declaration, parent as IrClass)
             } else {

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.fir.FirAnnotationContainer
 import org.jetbrains.kotlin.fir.backend.generators.AnnotationGenerator
+import org.jetbrains.kotlin.fir.backend.generators.DelegatedMemberGenerator
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.impl.FirDefaultPropertyGetter
 import org.jetbrains.kotlin.fir.declarations.impl.FirDefaultPropertySetter
@@ -36,12 +37,9 @@ import org.jetbrains.kotlin.ir.declarations.impl.*
 import org.jetbrains.kotlin.ir.descriptors.*
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrSyntheticBodyKind
-import org.jetbrains.kotlin.ir.expressions.impl.IrErrorExpressionImpl
-import org.jetbrains.kotlin.ir.expressions.impl.IrExpressionBodyImpl
+import org.jetbrains.kotlin.ir.expressions.impl.*
 import org.jetbrains.kotlin.ir.symbols.*
-import org.jetbrains.kotlin.ir.types.IrErrorType
-import org.jetbrains.kotlin.ir.types.IrSimpleType
-import org.jetbrains.kotlin.ir.types.IrType
+import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
@@ -78,6 +76,8 @@ class Fir2IrDeclarationStorage(
 
     private val localStorage = Fir2IrLocalStorage()
 
+    private val delegatedMemberGenerator = DelegatedMemberGenerator(components)
+
     private fun areCompatible(firFunction: FirFunction<*>, irFunction: IrFunction): Boolean {
         if (firFunction is FirSimpleFunction && irFunction is IrSimpleFunction) {
             if (irFunction.name != firFunction.name) return false
@@ -700,9 +700,39 @@ class Fir2IrDeclarationStorage(
 
     fun getCachedIrProperty(property: FirProperty): IrProperty? = propertyCache[property]
 
-    private fun createIrField(field: FirField): IrField {
+    fun getCachedIrField(field: FirField): IrField? = fieldCache[field]
+
+    fun createIrFieldAndDelegatedMembers(field: FirField, parent: IrClass): IrField {
+        val irField = createIrField(field, origin = IrDeclarationOrigin.DELEGATE)
+        irField.setAndModifyParent(parent)
+        delegatedMemberGenerator.generate(irField, parent)
+        return irField
+    }
+
+    internal fun findOverriddenFirFunction(irFunction: IrSimpleFunction, superClassId: ClassId): FirFunction<*>? {
+        val functions = getFirClassByFqName(superClassId)?.declarations?.filter {
+            it is FirFunction<*> && functionCache.containsKey(it) && irFunction.overrides(functionCache[it]!!)
+        }
+        return if (functions.isNullOrEmpty()) null else functions.first() as FirFunction<*>
+    }
+
+    internal fun findOverriddenFirProperty(irProperty: IrProperty, superClassId: ClassId): FirProperty? {
+        val properties = getFirClassByFqName(superClassId)?.declarations?.filter {
+            it is FirProperty && it.name == irProperty.name
+        }
+        return if (properties.isNullOrEmpty()) null else properties.first() as FirProperty
+    }
+
+    private fun getFirClassByFqName(classId: ClassId): FirClass<*>? {
+        val declaration = firProvider.getClassLikeSymbolByFqName(classId) ?: firSymbolProvider.getClassLikeSymbolByFqName(classId)
+        return declaration?.fir as? FirClass<*>
+    }
+
+    private fun createIrField(
+        field: FirField,
+        origin: IrDeclarationOrigin = IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB
+    ): IrField {
         val descriptor = WrappedFieldDescriptor()
-        val origin = IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB
         val type = field.returnTypeRef.toIrType()
         return field.convertWithOffsets { startOffset, endOffset ->
             symbolTable.declareField(

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt

@@ -76,6 +76,14 @@ class Fir2IrVisitor(
         TODO("Should not be here: ${element.render()}")
     }
 
+    override fun visitField(field: FirField, data: Any?): IrField {
+        if (field.isSynthetic) {
+            return declarationStorage.getCachedIrField(field)!!
+        } else {
+            throw AssertionError("Unexpected field: ${field.render()}")
+        }
+    }
+
     override fun visitFile(file: FirFile, data: Any?): IrFile {
         return conversionScope.withParent(declarationStorage.getIrFile(file)) {
             file.declarations.forEach {

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/ClassMemberGenerator.kt

@@ -59,6 +59,16 @@ internal class ClassMemberGenerator(
                     else -> null
                 }
             }
+            // Add delegated members *before* fake override generations.
+            // Otherwise, fake overrides for delegated members, which are redundant, will be added.
+            irClass.declarations.filter {
+                it.origin == IrDeclarationOrigin.DELEGATED_MEMBER
+            }.forEach {
+                when (it) {
+                    is IrSimpleFunction -> processedCallableNames += it.name
+                    is IrProperty -> processedCallableNames += it.name
+                }
+            }
             // Add synthetic members *before* fake override generations.
             // Otherwise, redundant members, e.g., synthetic toString _and_ fake override toString, will be added.
             if (irClass.isInline && klass.getPrimaryConstructorIfAny() != null) {

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DelegatedMemberGenerator.kt

@@ -0,0 +1,271 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.backend.generators
+
+import org.jetbrains.kotlin.backend.common.ir.isFinalClass
+import org.jetbrains.kotlin.backend.common.ir.isOverridable
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.descriptors.Visibilities
+import org.jetbrains.kotlin.fir.backend.Fir2IrComponents
+import org.jetbrains.kotlin.fir.backend.FirMetadataSource
+import org.jetbrains.kotlin.fir.backend.declareThisReceiverParameter
+import org.jetbrains.kotlin.fir.backend.isOverriding
+import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.declarations.builder.buildProperty
+import org.jetbrains.kotlin.fir.declarations.builder.buildSimpleFunction
+import org.jetbrains.kotlin.fir.declarations.builder.buildValueParameterCopy
+import org.jetbrains.kotlin.fir.declarations.impl.FirDeclarationStatusImpl
+import org.jetbrains.kotlin.fir.symbols.CallableId
+import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirVariableSymbol
+import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.declarations.impl.IrFunctionImpl
+import org.jetbrains.kotlin.ir.declarations.impl.IrPropertyImpl
+import org.jetbrains.kotlin.ir.declarations.impl.IrValueParameterImpl
+import org.jetbrains.kotlin.ir.descriptors.WrappedPropertyDescriptor
+import org.jetbrains.kotlin.ir.descriptors.WrappedSimpleFunctionDescriptor
+import org.jetbrains.kotlin.ir.descriptors.WrappedValueParameterDescriptor
+import org.jetbrains.kotlin.ir.expressions.impl.*
+import org.jetbrains.kotlin.ir.types.classOrNull
+import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeImpl
+import org.jetbrains.kotlin.ir.types.isNothing
+import org.jetbrains.kotlin.ir.types.isUnit
+import org.jetbrains.kotlin.ir.util.classId
+import org.jetbrains.kotlin.ir.util.defaultType
+import org.jetbrains.kotlin.ir.util.hasAnnotation
+import org.jetbrains.kotlin.ir.util.isFakeOverride
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.Name
+
+/**
+ * A generator for delegated members from implementation by delegation.
+ *
+ * It assumes a synthetic field with the super-interface type has been created for the delegate expression. It looks for delegatable
+ * methods and properties in the super-interface, and creates corresponding members in the subclass.
+ * TODO: generic super interface types and generic delegated members.
+ */
+internal class DelegatedMemberGenerator(
+    private val components: Fir2IrComponents
+) : Fir2IrComponents by components {
+
+    // Generate delegated members for [subClass]. The synthetic field [irField] has the super interface type.
+    fun generate(irField: IrField, subClass: IrClass) {
+        val superClass = (irField.type as IrSimpleTypeImpl)?.classOrNull?.owner ?: return
+        val superClassId = superClass.classId ?: return
+        superClass.declarations?.filter {
+            it.isDelegatable() && !subClass.declarations.any { decl -> isOverriding(irBuiltIns, decl, it) }
+        }?.forEach {
+            if (it is IrSimpleFunction) {
+                val firFunction = declarationStorage.findOverriddenFirFunction(it, superClassId) ?: return
+                val function = generateDelegatedFunction(subClass, irField, it, firFunction)
+                subClass.addMember(function)
+            } else if (it is IrProperty) {
+                val firProperty = declarationStorage.findOverriddenFirProperty(it, superClassId) ?: return
+                generateDelegatedProperty(subClass, irField, it, firProperty)
+            }
+        }
+    }
+
+    private fun IrDeclaration.isDelegatable(): Boolean {
+        return isOverridable()
+                && !isFakeOverride
+                && !(this is IrSimpleFunction && hasDefaultImplementation())
+    }
+
+    private fun IrDeclaration.isOverridable(): Boolean {
+        return when (this) {
+            is IrSimpleFunction -> this.isOverridable
+            is IrProperty -> visibility != Visibilities.PRIVATE && modality != Modality.FINAL && (parent as? IrClass)?.isFinalClass != true
+            else -> false
+        }
+    }
+
+    private fun IrSimpleFunction.hasDefaultImplementation(): Boolean {
+        var realFunction: IrSimpleFunction? = this
+        while (realFunction != null && realFunction.isFakeOverride) {
+            realFunction = realFunction.overriddenSymbols?.firstOrNull()?.owner
+        }
+        return realFunction != null
+                && (realFunction.modality != Modality.ABSTRACT && realFunction.origin == IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB
+                || realFunction.annotations.hasAnnotation(FqName("kotlin.jvm.JvmDefault")))
+    }
+
+    private fun generateDelegatedFunction(
+        subClass: IrClass,
+        irField: IrField,
+        superFunction: IrSimpleFunction,
+        firSuperFunction: FirFunction<*>
+    ): IrSimpleFunction {
+        val startOffset = irField.startOffset
+        val endOffset = irField.endOffset
+        val descriptor = WrappedSimpleFunctionDescriptor()
+        val origin = IrDeclarationOrigin.DELEGATED_MEMBER
+        val modality = if (superFunction.modality == Modality.ABSTRACT) Modality.OPEN else superFunction.modality
+        val delegateFunction = symbolTable.declareSimpleFunction(descriptor) { symbol ->
+            IrFunctionImpl(
+                startOffset,
+                endOffset,
+                origin,
+                symbol,
+                superFunction.name,
+                superFunction.visibility,
+                modality,
+                superFunction.returnType,
+                superFunction.isInline,
+                superFunction.isExternal,
+                superFunction.isTailrec,
+                superFunction.isSuspend,
+                superFunction.isOperator,
+                superFunction.isExpect
+            ).apply {
+                descriptor.bind(this)
+                declarationStorage.enterScope(this)
+                this.parent = subClass
+                overriddenSymbols += superFunction.symbol
+                dispatchReceiverParameter = declareThisReceiverParameter(symbolTable, subClass.defaultType, origin)
+                // TODO: type parameters from superFunctions and type substitution when super interface types are generic
+                superFunction.valueParameters.forEach { valueParameter ->
+                    val parameterDescriptor = WrappedValueParameterDescriptor()
+                    valueParameters += symbolTable.declareValueParameter(
+                        startOffset, endOffset, origin, parameterDescriptor, valueParameter.type
+                    ) { symbol ->
+                        IrValueParameterImpl(
+                            startOffset, endOffset, origin, symbol,
+                            valueParameter.name, valueParameter.index, valueParameter.type,
+                            null, valueParameter.isCrossinline, valueParameter.isNoinline
+                        ).also {
+                            parameterDescriptor.bind(it)
+                            it.parent = this
+                        }
+                    }
+                }
+
+                val visibility = when (firSuperFunction) {
+                    is FirSimpleFunction -> firSuperFunction.status.visibility
+                    is FirPropertyAccessor -> firSuperFunction.status.visibility
+                    else -> Visibilities.PUBLIC
+                }
+                metadata = FirMetadataSource.Function(
+                    buildSimpleFunction {
+                        this.origin = FirDeclarationOrigin.Synthetic
+                        this.name = superFunction.name
+                        this.symbol = FirNamedFunctionSymbol(getCallableId(subClass, superFunction.name))
+                        this.status = FirDeclarationStatusImpl(visibility, modality)
+                        this.session = components.session
+                        this.returnTypeRef = firSuperFunction.returnTypeRef
+                        firSuperFunction.valueParameters.map { superParameter ->
+                            this.valueParameters.add(
+                                buildValueParameterCopy(superParameter) {
+                                    this.origin = FirDeclarationOrigin.Synthetic
+                                    this.session = components.session
+                                    this.symbol = FirVariableSymbol(superParameter.name)
+                                }
+                            )
+                        }
+                    }
+                )
+
+                declarationStorage.leaveScope(this)
+            }
+        }
+
+        val body = IrBlockBodyImpl(startOffset, endOffset)
+        val irCall = IrCallImpl(
+            startOffset,
+            endOffset,
+            superFunction.returnType,
+            superFunction.symbol,
+            superFunction.typeParameters.size,
+            superFunction.valueParameters.size
+        ).apply {
+            dispatchReceiver =
+                IrGetFieldImpl(
+                    startOffset, endOffset,
+                    irField.symbol,
+                    irField.type,
+                    IrGetValueImpl(
+                        startOffset, endOffset,
+                        delegateFunction.dispatchReceiverParameter?.type!!,
+                        delegateFunction.dispatchReceiverParameter?.symbol!!
+                    )
+                )
+            extensionReceiver =
+                delegateFunction.extensionReceiverParameter?.let { extensionReceiver ->
+                    IrGetValueImpl(startOffset, endOffset, extensionReceiver.type, extensionReceiver.symbol)
+                }
+            delegateFunction.valueParameters.forEach {
+                putValueArgument(it.index, IrGetValueImpl(startOffset, endOffset, it.type, it.symbol))
+            }
+        }
+        if (superFunction.returnType.isUnit() || superFunction.returnType.isNothing()) {
+            body.statements.add(irCall)
+        } else {
+            val irReturn = IrReturnImpl(startOffset, endOffset, irBuiltIns.nothingType, delegateFunction.symbol, irCall)
+            body.statements.add(irReturn)
+        }
+        delegateFunction.body = body
+        return delegateFunction
+    }
+
+    private fun generateDelegatedProperty(
+        subClass: IrClass,
+        irField: IrField,
+        superProperty: IrProperty,
+        firSuperProperty: FirProperty
+    ) {
+        val startOffset = irField.startOffset
+        val endOffset = irField.endOffset
+        val descriptor = WrappedPropertyDescriptor()
+        val modality = if (superProperty.modality == Modality.ABSTRACT) Modality.OPEN else superProperty.modality
+        symbolTable.declareProperty(
+            startOffset, endOffset,
+            IrDeclarationOrigin.DELEGATED_MEMBER, descriptor, superProperty.isDelegated
+        ) { symbol ->
+            IrPropertyImpl(
+                startOffset, endOffset, IrDeclarationOrigin.DELEGATED_MEMBER, symbol,
+                superProperty.name, superProperty.visibility,
+                modality,
+                isVar = superProperty.isVar,
+                isConst = superProperty.isConst,
+                isLateinit = superProperty.isLateinit,
+                isDelegated = superProperty.isDelegated,
+                isExternal = false,
+                isExpect = superProperty.isExpect,
+                isFakeOverride = false
+            ).apply {
+                descriptor.bind(this)
+                this.parent = subClass
+                getter = generateDelegatedFunction(subClass, irField, superProperty.getter!!, firSuperProperty.getter!!).apply {
+                    this.correspondingPropertySymbol = symbol
+                }
+                if (superProperty.isVar) {
+                    setter = generateDelegatedFunction(subClass, irField, superProperty.setter!!, firSuperProperty.setter!!).apply {
+                        this.correspondingPropertySymbol = symbol
+                    }
+                }
+                this.metadata = FirMetadataSource.Property(
+                    buildProperty {
+                        this.name = superProperty.name
+                        this.origin = FirDeclarationOrigin.Synthetic
+                        this.session = components.session
+                        this.status = FirDeclarationStatusImpl(firSuperProperty.status.visibility, modality)
+                        this.isLocal = firSuperProperty.isLocal
+                        this.returnTypeRef = firSuperProperty.returnTypeRef
+                        this.symbol = FirPropertySymbol(getCallableId(subClass, superProperty.name))
+                        this.isVar = firSuperProperty.isVar
+                    }
+                )
+                subClass.addMember(this)
+            }
+        }
+    }
+
+    private fun getCallableId(irClass: IrClass, name: Name): CallableId {
+        val classId = irClass.classId
+        return if (classId != null) CallableId(classId, name) else CallableId(name)
+    }
+}

compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/DeclarationsConverter.kt

@@ -36,6 +36,7 @@ import org.jetbrains.kotlin.fir.lightTree.fir.modifier.Modifier
 import org.jetbrains.kotlin.fir.lightTree.fir.modifier.TypeModifier
 import org.jetbrains.kotlin.fir.lightTree.fir.modifier.TypeParameterModifier
 import org.jetbrains.kotlin.fir.lightTree.fir.modifier.TypeProjectionModifier
+import org.jetbrains.kotlin.fir.references.builder.buildSimpleNamedReference
 import org.jetbrains.kotlin.fir.scopes.FirScopeProvider
 import org.jetbrains.kotlin.fir.symbols.CallableId
 import org.jetbrains.kotlin.fir.symbols.impl.*
@@ -408,6 +409,8 @@ class DeclarationsConverter(
                     val delegationSpecifiers = superTypeList?.let { convertDelegationSpecifiers(it) }
                     var delegatedSuperTypeRef: FirTypeRef? = delegationSpecifiers?.delegatedSuperTypeRef
                     val delegatedConstructorSource: FirLightSourceElement? = delegationSpecifiers?.delegatedConstructorSource
+                    delegationSpecifiers?.delegateFields?.map { declarations += it }
+
                     val superTypeCallEntry = delegationSpecifiers?.delegatedConstructorArguments.orEmpty()
                     val superTypeRefs = mutableListOf<FirTypeRef>()
 
@@ -449,7 +452,10 @@ class DeclarationsConverter(
                         superTypeCallEntry = superTypeCallEntry
                     )
                     //parse primary constructor
-                    val primaryConstructorWrapper = convertPrimaryConstructor(primaryConstructor, classWrapper, delegatedConstructorSource)
+                    val primaryConstructorWrapper = convertPrimaryConstructor(
+                        primaryConstructor, classWrapper, delegatedConstructorSource,
+                        delegationSpecifiers?.primaryConstructorBody
+                    )
                     val firPrimaryConstructor = primaryConstructorWrapper?.firConstructor
                     firPrimaryConstructor?.let { declarations += it }
 
@@ -503,6 +509,8 @@ class DeclarationsConverter(
         var delegatedSuperTypeRef: FirTypeRef? = null
         var classBody: LighterASTNode? = null
         var delegatedConstructorSource: FirLightSourceElement? = null
+        var delegateFields: List<FirField>? = null
+        var primaryConstructorBody: FirBlock? = null
         objectLiteral.getChildNodesByType(OBJECT_DECLARATION).first().forEachChildren {
             when (it.tokenType) {
                 MODIFIER_LIST -> modifiers = convertModifierList(it)
@@ -512,6 +520,8 @@ class DeclarationsConverter(
                     superTypeRefs += it.superTypesRef
                     superTypeCallEntry += it.delegatedConstructorArguments
                     delegatedConstructorSource = it.delegatedConstructorSource
+                    delegateFields = it.delegateFields
+                    primaryConstructorBody = it.primaryConstructorBody
                 }
                 CLASS_BODY -> classBody = it
             }
@@ -537,6 +547,7 @@ class DeclarationsConverter(
                 this.superTypeRefs += superTypeRefs
                 typeRef = delegatedSelfType
 
+                delegateFields?.map { this.declarations += it }
                 val classWrapper = ClassWrapper(
                     SpecialNames.NO_NAME_PROVIDED, modifiers, ClassKind.OBJECT, this,
                     hasPrimaryConstructor = false,
@@ -547,7 +558,7 @@ class DeclarationsConverter(
                     superTypeCallEntry = superTypeCallEntry
                 )
                 //parse primary constructor
-                convertPrimaryConstructor(primaryConstructor, classWrapper, delegatedConstructorSource)
+                convertPrimaryConstructor(primaryConstructor, classWrapper, delegatedConstructorSource, primaryConstructorBody)
                     ?.let { this.declarations += it.firConstructor }
 
                 //parse declarations
@@ -666,7 +677,8 @@ class DeclarationsConverter(
     private fun convertPrimaryConstructor(
         primaryConstructor: LighterASTNode?,
         classWrapper: ClassWrapper,
-        delegatedConstructorSource: FirLightSourceElement?
+        delegatedConstructorSource: FirLightSourceElement?,
+        body: FirBlock? = null
     ): PrimaryConstructor? {
         if (primaryConstructor == null && !classWrapper.isEnumEntry() && classWrapper.hasSecondaryConstructor) return null
         if (classWrapper.isInterface()) return null
@@ -709,6 +721,7 @@ class DeclarationsConverter(
                 typeParameters += constructorTypeParametersFromConstructedClass(classWrapper.classBuilder.typeParameters)
                 this.valueParameters += valueParameters.map { it.firValueParameter }
                 delegatedConstructor = firDelegatedCall
+                this.body = body
             }, valueParameters
         )
     }
@@ -1303,7 +1316,9 @@ class DeclarationsConverter(
         val delegatedSuperTypeRef: FirTypeRef?,
         val superTypesRef: List<FirTypeRef>,
         val delegatedConstructorArguments: List<FirExpression>,
-        val delegatedConstructorSource: FirLightSourceElement?
+        val delegatedConstructorSource: FirLightSourceElement?,
+        val delegateFields: List<FirField>,
+        val primaryConstructorBody: FirBlock?
     )
 
     private fun convertDelegationSpecifiers(delegationSpecifiers: LighterASTNode): DelegationSpecifiers {
@@ -1311,6 +1326,9 @@ class DeclarationsConverter(
         val superTypeCallEntry = mutableListOf<FirExpression>()
         var delegatedSuperTypeRef: FirTypeRef? = null
         var delegateConstructorSource: FirLightSourceElement? = null
+        val delegateFields = mutableListOf<FirField>()
+        val initializeDelegateStatements = mutableListOf<FirStatement>()
+        var delegateNumber = 0
         delegationSpecifiers.forEachChildren {
             when (it.tokenType) {
                 SUPER_TYPE_ENTRY -> superTypeRefs += convertType(it)
@@ -1320,10 +1338,23 @@ class DeclarationsConverter(
                     superTypeCallEntry += second
                     delegateConstructorSource = it.toFirSourceElement()
                 }
-                DELEGATED_SUPER_TYPE_ENTRY -> superTypeRefs += convertExplicitDelegation(it)
+                DELEGATED_SUPER_TYPE_ENTRY -> {
+                    superTypeRefs += convertExplicitDelegation(it, delegateNumber, delegateFields, initializeDelegateStatements)
+                    delegateNumber++
+                }
             }
         }
-        return DelegationSpecifiers(delegatedSuperTypeRef, superTypeRefs, superTypeCallEntry, delegateConstructorSource)
+        val body = if (initializeDelegateStatements.isNotEmpty()) {
+            buildBlock {
+                for (statement in initializeDelegateStatements) {
+                    statements += statement
+                }
+            }
+        } else null
+        return DelegationSpecifiers(
+            delegatedSuperTypeRef, superTypeRefs, superTypeCallEntry, delegateConstructorSource,
+            delegateFields, body
+        )
     }
 
     /**
@@ -1352,7 +1383,12 @@ class DeclarationsConverter(
      *   : userType "by" element
      *   ;
      */
-    private fun convertExplicitDelegation(explicitDelegation: LighterASTNode): FirDelegatedTypeRef {
+    private fun convertExplicitDelegation(
+        explicitDelegation: LighterASTNode,
+        delegateNumber: Int,
+        delegateFields: MutableList<FirField>,
+        initializeDelegateStatements: MutableList<FirStatement>
+    ): FirTypeRef {
         lateinit var firTypeRef: FirTypeRef
         var firExpression: FirExpression? = buildErrorExpression(
             explicitDelegation.toFirSourceElement(), ConeSimpleDiagnostic("Should have delegate", DiagnosticKind.Syntax)
@@ -1364,10 +1400,30 @@ class DeclarationsConverter(
             }
         }
 
-        return buildDelegatedTypeRef {
-            delegate = firExpression
-            typeRef = firTypeRef
-        }
+        val delegateName = Name.identifier("\$\$delegate_$delegateNumber")
+        delegateFields.add(
+            buildField {
+                source = firExpression!!.source
+                session = baseSession
+                origin = FirDeclarationOrigin.Synthetic
+                name = delegateName
+                returnTypeRef = firTypeRef!!
+                symbol = FirFieldSymbol(CallableId(name))
+                isVar = false
+                status = FirDeclarationStatusImpl(Visibilities.LOCAL, Modality.FINAL)
+            }
+        )
+        initializeDelegateStatements.add(
+            buildVariableAssignment {
+                source = firExpression!!.source
+                calleeReference =
+                    buildSimpleNamedReference {
+                        name = delegateName
+                    }
+                rValue = firExpression!!
+            }
+        )
+        return firTypeRef
     }
 
     /*****    TYPES    *****/

compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.fir.expressions.impl.FirSingleExpressionBlock
 import org.jetbrains.kotlin.fir.references.FirNamedReference
 import org.jetbrains.kotlin.fir.references.builder.*
 import org.jetbrains.kotlin.fir.scopes.FirScopeProvider
+import org.jetbrains.kotlin.fir.symbols.CallableId
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.builder.*
@@ -48,7 +49,6 @@ import org.jetbrains.kotlin.util.OperatorNameConventions
 import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
 import java.util.*
 import org.jetbrains.kotlin.utils.addToStdlib.runIf
-import kotlin.collections.contains
 
 class RawFirBuilder(
     session: FirSession, val baseScopeProvider: FirScopeProvider, val stubMode: Boolean
@@ -459,6 +459,8 @@ class RawFirBuilder(
         ): FirTypeRef {
             var superTypeCallEntry: KtSuperTypeCallEntry? = null
             var delegatedSuperTypeRef: FirTypeRef? = null
+            var delegateNumber = 0
+            val initializeDelegateStatements = mutableListOf<FirStatement>()
             for (superTypeListEntry in superTypeListEntries) {
                 when (superTypeListEntry) {
                     is KtSuperTypeEntry -> {
@@ -471,10 +473,32 @@ class RawFirBuilder(
                     }
                     is KtDelegatedSuperTypeEntry -> {
                         val type = superTypeListEntry.typeReference.toFirOrErrorType()
-                        container.superTypeRefs += buildDelegatedTypeRef {
-                            delegate = { superTypeListEntry.delegateExpression }.toFirExpression("Should have delegate")
-                            typeRef = type
+                        val delegateExpression = { superTypeListEntry.delegateExpression }.toFirExpression("Should have delegate")
+                        container.superTypeRefs += type
+                        val delegateName = Name.identifier("\$\$delegate_$delegateNumber")
+                        val delegateSource = superTypeListEntry.delegateExpression?.toFirSourceElement()
+                        val delegateField = buildField {
+                            source = delegateSource
+                            session = baseSession
+                            origin = FirDeclarationOrigin.Synthetic
+                            name = delegateName
+                            returnTypeRef = type
+                            symbol = FirFieldSymbol(CallableId(name))
+                            isVar = false
+                            status = FirDeclarationStatusImpl(Visibilities.LOCAL, Modality.FINAL)
                         }
+                        initializeDelegateStatements.add(
+                            buildVariableAssignment {
+                                source = delegateSource
+                                calleeReference =
+                                    buildSimpleNamedReference {
+                                        name = delegateName
+                                    }
+                                rValue = delegateExpression
+                            }
+                        )
+                        container.declarations.add(delegateField)
+                        delegateNumber ++
                     }
                 }
             }
@@ -526,8 +550,14 @@ class RawFirBuilder(
                 delegatedSuperTypeRef,
                 delegatedSelfTypeRef ?: delegatedSuperTypeRef,
                 owner = this,
-                containerTypeParameters
+                containerTypeParameters,
+                body = if (initializeDelegateStatements.isNotEmpty()) buildBlock {
+                    for (statement in initializeDelegateStatements) {
+                        statements += statement
+                    }
+                } else null
             )
+
             container.declarations += firPrimaryConstructor
             return delegatedSuperTypeRef
         }
@@ -537,7 +567,8 @@ class RawFirBuilder(
             delegatedSuperTypeRef: FirTypeRef,
             delegatedSelfTypeRef: FirTypeRef,
             owner: KtClassOrObject,
-            ownerTypeParameters: List<FirTypeParameterRef>
+            ownerTypeParameters: List<FirTypeParameterRef>,
+            body: FirBlock? = null
         ): FirConstructor {
             val constructorCallee = superTypeCallEntry?.calleeExpression?.toFirSourceElement()
             val constructorSource = this?.toFirSourceElement()
@@ -577,6 +608,7 @@ class RawFirBuilder(
                 typeParameters += constructorTypeParametersFromConstructedClass(ownerTypeParameters)
                 this@toFirConstructor?.extractAnnotationsTo(this)
                 this@toFirConstructor?.extractValueParametersTo(this)
+                this.body = body
             }
         }
 
@@ -719,7 +751,7 @@ class RawFirBuilder(
                             classOrObject.extractSuperTypeListEntriesTo(this, delegatedSelfType, null, classKind, typeParameters)
 
                         val primaryConstructor = classOrObject.primaryConstructor
-                        val firPrimaryConstructor = declarations.firstOrNull() as? FirConstructor
+                        val firPrimaryConstructor = declarations.firstOrNull {it is FirConstructor} as? FirConstructor
                         if (primaryConstructor != null && firPrimaryConstructor != null) {
                             primaryConstructor.valueParameters.zip(
                                 firPrimaryConstructor.valueParameters

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirStatusResolveTransformer.kt

@@ -138,6 +138,14 @@ class FirStatusResolveTransformer(
         return transformDeclaration(property, data)
     }
 
+    override fun transformField(
+        field: FirField,
+        data: FirDeclarationStatus?
+    ): CompositeTransformResult<FirDeclaration> {
+        field.transformStatus(this, field.resolveStatus(field.status, containingClass, isLocal = false))
+        return transformDeclaration(field, data)
+    }
+
     override fun transformEnumEntry(enumEntry: FirEnumEntry, data: FirDeclarationStatus?): CompositeTransformResult<FirDeclaration> {
         return transformDeclaration(enumEntry, data)
     }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirDeclarationsResolveTransformer.kt

@@ -741,7 +741,7 @@ open class FirDeclarationsResolveTransformer(transformer: FirBodyResolveTransfor
             else
                 staticsAndCompanion
 
-        val constructor = (owner as? FirRegularClass)?.declarations?.firstOrNull() as? FirConstructor
+        val constructor = (owner as? FirRegularClass)?.declarations?.firstOrNull { it is FirConstructor } as? FirConstructor
         val primaryConstructorParametersScope =
             if (constructor?.isPrimary == true) {
                 constructor.valueParameters.fold(FirLocalScope()) { acc, param -> acc.storeVariable(param) }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/FirDeclarationUtil.kt

@@ -9,8 +9,8 @@ import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.fir.declarations.builder.FirRegularClassBuilder
 import org.jetbrains.kotlin.fir.declarations.builder.FirTypeParameterBuilder
-import org.jetbrains.kotlin.fir.declarations.impl.FirRegularClassImpl
 import org.jetbrains.kotlin.fir.declarations.impl.FirFileImpl
+import org.jetbrains.kotlin.fir.declarations.impl.FirRegularClassImpl
 import org.jetbrains.kotlin.fir.symbols.impl.FirAnonymousObjectSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
@@ -119,4 +119,7 @@ var FirProperty.isFromVararg: Boolean? by FirDeclarationDataRegistry.data(IsFrom
 
 fun FirAnnotatedDeclaration.hasAnnotation(classId: ClassId): Boolean {
     return annotations.any { it.annotationTypeRef.coneTypeSafe<ConeClassLikeType>()?.classId == classId }
-}
+}
+
+inline val FirDeclaration.isSynthetic: Boolean
+    get() = origin == FirDeclarationOrigin.Synthetic

compiler/testData/codegen/box/bridges/delegation.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A<T> {
     fun foo(): T
 }

compiler/testData/codegen/box/bridges/delegationProperty.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A<T> {
     var result: T
 }

compiler/testData/codegen/box/bridges/fakeGenericCovariantOverrideWithDelegation.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A<T> {
     fun foo(t: T): String
 }

compiler/testData/codegen/box/classes/delegation2.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface Trait1 {
     fun foo() : String
 }

compiler/testData/codegen/box/classes/inheritance.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // Changed when traits were introduced. May not make sense any more
 
 open class X(val x : Int) {}

compiler/testData/codegen/box/classes/kt2224.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A {
     fun foo(): Int
 }

compiler/testData/codegen/box/classes/kt285.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface Trait {
     fun foo() = "O"
     fun bar(): String

compiler/testData/codegen/box/classes/kt3001.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A {
     val result: String
 }

compiler/testData/codegen/box/classes/kt3414.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A {
     fun foo(): Int
 }

compiler/testData/codegen/box/closures/kt11634_3.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A {
     fun foo(): String
 }

compiler/testData/codegen/box/closures/kt11634_4.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A {
     fun foo(): String
 }

compiler/testData/codegen/box/coroutines/delegatedSuspendMember.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // WITH_RUNTIME
 // WITH_COROUTINES
 // COMMON_COROUTINES_TEST

compiler/testData/codegen/box/coroutines/inlineClasses/interfaceDelegateWithInlineClass.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // WITH_RUNTIME
 // WITH_COROUTINES
 // COMMON_COROUTINES_TEST

compiler/testData/codegen/box/coroutines/tailCallOptimizations/interfaceDelegation.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 // FULL_JDK
 // WITH_RUNTIME

compiler/testData/codegen/box/coroutines/tailCallToNothing.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // WITH_RUNTIME
 // WITH_COROUTINES
 import helpers.*

compiler/testData/codegen/box/coroutines/unitTypeReturn/interfaceDelegation.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // WITH_RUNTIME
 // WITH_COROUTINES
 

compiler/testData/codegen/box/delegation/defaultOverride.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // SKIP_JDK6
 // TARGET_BACKEND: JVM
 

compiler/testData/codegen/box/delegation/hiddenSuperOverrideIn1.0.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 public interface Base {
     fun test() = "base fail"
 }

compiler/testData/codegen/box/delegation/kt8154.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface A<T> {
     fun foo(): T
 }

compiler/testData/codegen/box/delegation/mixed.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // SKIP_JDK6
 // TARGET_BACKEND: JVM
 // FILE: Base.java

compiler/testData/codegen/box/enum/enumEntryReferenceFromInnerClassConstructor3.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface IFoo {
     fun foo(): String
 }

compiler/testData/codegen/box/inlineClasses/interfaceDelegation/interfaceImplementationByDelegation.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND_FIR: JVM_IR
 
 interface IFoo {
     fun getO(): String

compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegatedToInlineClassInt.kt

@@ -1,6 +1,5 @@
 // KJS_WITH_FULL_RUNTIME
 // WITH_RUNTIME
-// IGNORE_BACKEND_FIR: JVM_IR
 import kotlin.test.assertEquals
 
 interface IFoo {

compiler/testData/codegen/box/inlineClasses/interfaceDelegation/memberFunDelegatedToInlineClassLong.kt

@@ -1,6 +1,5 @@
 // KJS_WITH_FULL_RUNTIME
 // WITH_RUNTIME
-// IGNORE_BACKEND_FIR: JVM_IR
 import kotlin.test.assertEquals
 
 interface IFoo {

compiler/testData/codegen/box/properties/kt2655.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface TextField {
     fun getText(): String
     fun setText(text: String)

compiler/testData/codegen/box/properties/kt2786.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 interface FooTrait {
         val propertyTest: String
 }

compiler/testData/codegen/box/secondaryConstructors/delegationWithPrimary.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 internal interface A {
     fun foo(): String
 }

compiler/testData/codegen/box/strings/kt3571.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class Thing(delegate: CharSequence) : CharSequence by delegate
   
 fun box(): String {

compiler/testData/codegen/box/throws/delegationAndThrows.kt

@@ -1,6 +1,5 @@
 // !LANGUAGE: +DoNotGenerateThrowsForDelegatedKotlinMembers
 // TARGET_BACKEND: JVM
-// IGNORE_BACKEND_FIR: JVM_IR
 // WITH_RUNTIME
 // FILE: A.kt
 

compiler/testData/codegen/box/toArray/toArray.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 
 // WITH_RUNTIME

compiler/testData/codegen/box/toArray/toArrayFromJava.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 // The old backend thinks `toArray(): Array<Int?>` is the same as `toArray(): Array<Any?>`
 // IGNORE_BACKEND: JVM

compiler/testData/diagnostics/tests/annotations/annotationInheritance.fir.kt

@@ -4,5 +4,5 @@ interface T
 
 annotation class Ann: C()
 annotation class Ann2: T
-annotation class Ann3: T by a
+annotation class Ann3: T by <!ANNOTATION_CLASS_MEMBER!>a<!>
 annotation class Ann4: C(), T

compiler/testData/diagnostics/tests/override/MissingDelegate.fir.kt

@@ -1,3 +1,3 @@
-class C : Base1 by Base2(1) {
+class C : Base1 by <!UNRESOLVED_REFERENCE!>Base2<!>(1) {
   fun test() { }
 }

compiler/testData/ir/irText/classes/delegatedGenericImplementation.fir.txt

@@ -46,34 +46,59 @@ FILE fqName:<root> fileName:/delegatedGenericImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Test1 modality:FINAL visibility:public superTypes:[<root>.IBase<E of <root>.Test1>]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <B> ($this:<root>.IBase<A of <root>.IBase>, a:E of <root>.Test1, b:B of <root>.Test1.foo) returnType:kotlin.Unit [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<E of <root>.Test1> visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.Test1<E of <root>.Test1> declared in <root>.Test1' type=<root>.Test1<E of <root>.Test1> origin=null
+          value: GET_VAR 'i: <root>.IBase<E of <root>.Test1> declared in <root>.Test1.<init>' type=<root>.IBase<E of <root>.Test1> origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.Test1<E of <root>.Test1>, a:A of <root>.IBase, b:B of <root>.IBase.foo) returnType:kotlin.Unit
       overridden:
         public abstract fun foo <B> (a: A of <root>.IBase, b: B of <root>.IBase.foo): kotlin.Unit declared in <root>.IBase
-      TYPE_PARAMETER name:B index:0 variance: superTypes:[kotlin.Any?]
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase<A of <root>.IBase>
-      VALUE_PARAMETER name:a index:0 type:E of <root>.Test1
-      VALUE_PARAMETER name:b index:1 type:B of <root>.Test1.foo
-    PROPERTY FAKE_OVERRIDE name:id visibility:public modality:ABSTRACT [fake_override,val]
-      FUN FAKE_OVERRIDE name:<get-id> visibility:public modality:ABSTRACT <C> ($this:<root>.IBase<A of <root>.IBase>) returnType:kotlin.collections.Map<E of <root>.Test1, C of <root>.Test1.<get-id>>? [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:id visibility:public modality:ABSTRACT [fake_override,val]
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test1<E of <root>.Test1>
+      VALUE_PARAMETER DELEGATED_MEMBER name:a index:0 type:A of <root>.IBase
+      VALUE_PARAMETER DELEGATED_MEMBER name:b index:1 type:B of <root>.IBase.foo
+      BLOCK_BODY
+        CALL 'public abstract fun foo <B> (a: A of <root>.IBase, b: B of <root>.IBase.foo): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+          <B>: <none>
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<E of <root>.Test1> visibility:local [final]' type=<root>.IBase<E of <root>.Test1> origin=null
+            receiver: GET_VAR '<this>: <root>.Test1<E of <root>.Test1> declared in <root>.Test1.foo' type=<root>.Test1<E of <root>.Test1> origin=null
+          a: GET_VAR 'a: A of <root>.IBase declared in <root>.Test1.foo' type=A of <root>.IBase origin=null
+          b: GET_VAR 'b: B of <root>.IBase.foo declared in <root>.Test1.foo' type=B of <root>.IBase.foo origin=null
+    PROPERTY DELEGATED_MEMBER name:id visibility:public modality:OPEN [val]
+      FUN DELEGATED_MEMBER name:<get-id> visibility:public modality:OPEN <> ($this:<root>.Test1<E of <root>.Test1>) returnType:kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>?
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:id visibility:public modality:OPEN [val]
         overridden:
           public abstract fun <get-id> <C> (): kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>? declared in <root>.IBase
-        TYPE_PARAMETER name:C index:0 variance: superTypes:[kotlin.Any?]
-        $this: VALUE_PARAMETER name:<this> type:<root>.IBase<A of <root>.IBase>
-    PROPERTY FAKE_OVERRIDE name:x visibility:public modality:ABSTRACT [fake_override,var]
-      FUN FAKE_OVERRIDE name:<get-x> visibility:public modality:ABSTRACT <D> ($this:<root>.IBase<A of <root>.IBase>) returnType:D of <root>.Test1.<get-x>? [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:x visibility:public modality:ABSTRACT [fake_override,var]
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test1<E of <root>.Test1>
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-id> (): kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>? declared in <root>.Test1'
+            CALL 'public abstract fun <get-id> <C> (): kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>? declared in <root>.IBase' type=kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>? origin=null
+              <C>: <none>
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<E of <root>.Test1> visibility:local [final]' type=<root>.IBase<E of <root>.Test1> origin=null
+                receiver: GET_VAR '<this>: <root>.Test1<E of <root>.Test1> declared in <root>.Test1.<get-id>' type=<root>.Test1<E of <root>.Test1> origin=null
+    PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [var]
+      FUN DELEGATED_MEMBER name:<get-x> visibility:public modality:OPEN <> ($this:<root>.Test1<E of <root>.Test1>) returnType:D of <root>.IBase.<get-x>?
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [var]
         overridden:
           public abstract fun <get-x> <D> (): D of <root>.IBase.<get-x>? declared in <root>.IBase
-        TYPE_PARAMETER name:D index:0 variance: superTypes:[kotlin.Any?]
-        $this: VALUE_PARAMETER name:<this> type:<root>.IBase<A of <root>.IBase>
-      FUN FAKE_OVERRIDE name:<set-x> visibility:public modality:ABSTRACT <D> ($this:<root>.IBase<A of <root>.IBase>, <set-?>:D of <root>.Test1.<set-x>?) returnType:kotlin.Unit [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:x visibility:public modality:ABSTRACT [fake_override,var]
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test1<E of <root>.Test1>
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-x> (): D of <root>.IBase.<get-x>? declared in <root>.Test1'
+            CALL 'public abstract fun <get-x> <D> (): D of <root>.IBase.<get-x>? declared in <root>.IBase' type=D of <root>.IBase.<get-x>? origin=null
+              <D>: <none>
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<E of <root>.Test1> visibility:local [final]' type=<root>.IBase<E of <root>.Test1> origin=null
+                receiver: GET_VAR '<this>: <root>.Test1<E of <root>.Test1> declared in <root>.Test1.<get-x>' type=<root>.Test1<E of <root>.Test1> origin=null
+      FUN DELEGATED_MEMBER name:<set-x> visibility:public modality:OPEN <> ($this:<root>.Test1<E of <root>.Test1>, <set-?>:D of <root>.IBase.<set-x>?) returnType:kotlin.Unit
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [var]
         overridden:
           public abstract fun <set-x> <D> (<set-?>: D of <root>.IBase.<set-x>?): kotlin.Unit declared in <root>.IBase
-        TYPE_PARAMETER name:D index:0 variance: superTypes:[kotlin.Any?]
-        $this: VALUE_PARAMETER name:<this> type:<root>.IBase<A of <root>.IBase>
-        VALUE_PARAMETER name:<set-?> index:0 type:D of <root>.Test1.<set-x>?
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test1<E of <root>.Test1>
+        VALUE_PARAMETER DELEGATED_MEMBER name:<set-?> index:0 type:D of <root>.IBase.<set-x>?
+        BLOCK_BODY
+          CALL 'public abstract fun <set-x> <D> (<set-?>: D of <root>.IBase.<set-x>?): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+            <D>: <none>
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<E of <root>.Test1> visibility:local [final]' type=<root>.IBase<E of <root>.Test1> origin=null
+              receiver: GET_VAR '<this>: <root>.Test1<E of <root>.Test1> declared in <root>.Test1.<set-x>' type=<root>.Test1<E of <root>.Test1> origin=null
+            <set-?>: GET_VAR '<set-?>: D of <root>.IBase.<set-x>? declared in <root>.Test1.<set-x>' type=D of <root>.IBase.<set-x>? origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<E of <root>.Test1> visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
@@ -94,6 +119,9 @@ FILE fqName:<root> fileName:/delegatedGenericImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Test2 modality:FINAL visibility:public superTypes:[<root>.IBase<kotlin.String>]'
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<kotlin.String> visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2' type=<root>.Test2 origin=null
+          value: GET_VAR 'j: <root>.IBase<kotlin.String> declared in <root>.Test2.<init>' type=<root>.IBase<kotlin.String> origin=null
     PROPERTY name:j visibility:public modality:FINAL [var]
       FIELD PROPERTY_BACKING_FIELD name:j type:<root>.IBase<kotlin.String> visibility:private
         EXPRESSION_BODY
@@ -113,34 +141,56 @@ FILE fqName:<root> fileName:/delegatedGenericImplementation.kt
           SET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:j type:<root>.IBase<kotlin.String> visibility:private' type=kotlin.Unit origin=null
             receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<set-j>' type=<root>.Test2 origin=null
             value: GET_VAR '<set-?>: <root>.IBase<kotlin.String> declared in <root>.Test2.<set-j>' type=<root>.IBase<kotlin.String> origin=null
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <B> ($this:<root>.IBase<A of <root>.IBase>, a:kotlin.String, b:B of <root>.Test2.foo) returnType:kotlin.Unit [fake_override]
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.Test2, a:A of <root>.IBase, b:B of <root>.IBase.foo) returnType:kotlin.Unit
       overridden:
         public abstract fun foo <B> (a: A of <root>.IBase, b: B of <root>.IBase.foo): kotlin.Unit declared in <root>.IBase
-      TYPE_PARAMETER name:B index:0 variance: superTypes:[kotlin.Any?]
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase<A of <root>.IBase>
-      VALUE_PARAMETER name:a index:0 type:kotlin.String
-      VALUE_PARAMETER name:b index:1 type:B of <root>.Test2.foo
-    PROPERTY FAKE_OVERRIDE name:id visibility:public modality:ABSTRACT [fake_override,val]
-      FUN FAKE_OVERRIDE name:<get-id> visibility:public modality:ABSTRACT <C> ($this:<root>.IBase<A of <root>.IBase>) returnType:kotlin.collections.Map<kotlin.String, C of <root>.Test2.<get-id>>? [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:id visibility:public modality:ABSTRACT [fake_override,val]
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+      VALUE_PARAMETER DELEGATED_MEMBER name:a index:0 type:A of <root>.IBase
+      VALUE_PARAMETER DELEGATED_MEMBER name:b index:1 type:B of <root>.IBase.foo
+      BLOCK_BODY
+        CALL 'public abstract fun foo <B> (a: A of <root>.IBase, b: B of <root>.IBase.foo): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+          <B>: <none>
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<kotlin.String> visibility:local [final]' type=<root>.IBase<kotlin.String> origin=null
+            receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.foo' type=<root>.Test2 origin=null
+          a: GET_VAR 'a: A of <root>.IBase declared in <root>.Test2.foo' type=A of <root>.IBase origin=null
+          b: GET_VAR 'b: B of <root>.IBase.foo declared in <root>.Test2.foo' type=B of <root>.IBase.foo origin=null
+    PROPERTY DELEGATED_MEMBER name:id visibility:public modality:OPEN [val]
+      FUN DELEGATED_MEMBER name:<get-id> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>?
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:id visibility:public modality:OPEN [val]
         overridden:
           public abstract fun <get-id> <C> (): kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>? declared in <root>.IBase
-        TYPE_PARAMETER name:C index:0 variance: superTypes:[kotlin.Any?]
-        $this: VALUE_PARAMETER name:<this> type:<root>.IBase<A of <root>.IBase>
-    PROPERTY FAKE_OVERRIDE name:x visibility:public modality:ABSTRACT [fake_override,var]
-      FUN FAKE_OVERRIDE name:<get-x> visibility:public modality:ABSTRACT <D> ($this:<root>.IBase<A of <root>.IBase>) returnType:D of <root>.Test2.<get-x>? [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:x visibility:public modality:ABSTRACT [fake_override,var]
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-id> (): kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>? declared in <root>.Test2'
+            CALL 'public abstract fun <get-id> <C> (): kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>? declared in <root>.IBase' type=kotlin.collections.Map<A of <root>.IBase, C of <root>.IBase.<get-id>>? origin=null
+              <C>: <none>
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<kotlin.String> visibility:local [final]' type=<root>.IBase<kotlin.String> origin=null
+                receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<get-id>' type=<root>.Test2 origin=null
+    PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [var]
+      FUN DELEGATED_MEMBER name:<get-x> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:D of <root>.IBase.<get-x>?
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [var]
         overridden:
           public abstract fun <get-x> <D> (): D of <root>.IBase.<get-x>? declared in <root>.IBase
-        TYPE_PARAMETER name:D index:0 variance: superTypes:[kotlin.Any?]
-        $this: VALUE_PARAMETER name:<this> type:<root>.IBase<A of <root>.IBase>
-      FUN FAKE_OVERRIDE name:<set-x> visibility:public modality:ABSTRACT <D> ($this:<root>.IBase<A of <root>.IBase>, <set-?>:D of <root>.Test2.<set-x>?) returnType:kotlin.Unit [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:x visibility:public modality:ABSTRACT [fake_override,var]
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-x> (): D of <root>.IBase.<get-x>? declared in <root>.Test2'
+            CALL 'public abstract fun <get-x> <D> (): D of <root>.IBase.<get-x>? declared in <root>.IBase' type=D of <root>.IBase.<get-x>? origin=null
+              <D>: <none>
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<kotlin.String> visibility:local [final]' type=<root>.IBase<kotlin.String> origin=null
+                receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<get-x>' type=<root>.Test2 origin=null
+      FUN DELEGATED_MEMBER name:<set-x> visibility:public modality:OPEN <> ($this:<root>.Test2, <set-?>:D of <root>.IBase.<set-x>?) returnType:kotlin.Unit
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [var]
         overridden:
           public abstract fun <set-x> <D> (<set-?>: D of <root>.IBase.<set-x>?): kotlin.Unit declared in <root>.IBase
-        TYPE_PARAMETER name:D index:0 variance: superTypes:[kotlin.Any?]
-        $this: VALUE_PARAMETER name:<this> type:<root>.IBase<A of <root>.IBase>
-        VALUE_PARAMETER name:<set-?> index:0 type:D of <root>.Test2.<set-x>?
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        VALUE_PARAMETER DELEGATED_MEMBER name:<set-?> index:0 type:D of <root>.IBase.<set-x>?
+        BLOCK_BODY
+          CALL 'public abstract fun <set-x> <D> (<set-?>: D of <root>.IBase.<set-x>?): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+            <D>: <none>
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<kotlin.String> visibility:local [final]' type=<root>.IBase<kotlin.String> origin=null
+              receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<set-x>' type=<root>.Test2 origin=null
+            <set-?>: GET_VAR '<set-?>: D of <root>.IBase.<set-x>? declared in <root>.Test2.<set-x>' type=D of <root>.IBase.<set-x>? origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<kotlin.String> visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any

compiler/testData/ir/irText/classes/delegatedImplementation.fir.txt

@@ -200,21 +200,39 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Test1 modality:FINAL visibility:public superTypes:[<root>.IBase]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IBase, x:kotlin.Int, s:kotlin.String) returnType:kotlin.Unit [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.Test1 declared in <root>.Test1' type=<root>.Test1 origin=null
+          value: GET_OBJECT 'CLASS OBJECT name:BaseImpl modality:FINAL visibility:public superTypes:[<root>.IBase]' type=<root>.BaseImpl
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.Test1, x:kotlin.Int, s:kotlin.String) returnType:kotlin.Unit
       overridden:
         public abstract fun foo (x: kotlin.Int, s: kotlin.String): kotlin.Unit declared in <root>.IBase
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase
-      VALUE_PARAMETER name:x index:0 type:kotlin.Int
-      VALUE_PARAMETER name:s index:1 type:kotlin.String
-    FUN FAKE_OVERRIDE name:bar visibility:public modality:ABSTRACT <> ($this:<root>.IBase) returnType:kotlin.Int [fake_override]
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test1
+      VALUE_PARAMETER DELEGATED_MEMBER name:x index:0 type:kotlin.Int
+      VALUE_PARAMETER DELEGATED_MEMBER name:s index:1 type:kotlin.String
+      BLOCK_BODY
+        CALL 'public abstract fun foo (x: kotlin.Int, s: kotlin.String): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
+            receiver: GET_VAR '<this>: <root>.Test1 declared in <root>.Test1.foo' type=<root>.Test1 origin=null
+          x: GET_VAR 'x: kotlin.Int declared in <root>.Test1.foo' type=kotlin.Int origin=null
+          s: GET_VAR 's: kotlin.String declared in <root>.Test1.foo' type=kotlin.String origin=null
+    FUN DELEGATED_MEMBER name:bar visibility:public modality:OPEN <> ($this:<root>.Test1) returnType:kotlin.Int
       overridden:
         public abstract fun bar (): kotlin.Int declared in <root>.IBase
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase
-    FUN FAKE_OVERRIDE name:qux visibility:public modality:ABSTRACT <> ($this:<root>.IBase, $receiver:kotlin.String) returnType:kotlin.Unit [fake_override]
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test1
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun bar (): kotlin.Int declared in <root>.Test1'
+          CALL 'public abstract fun bar (): kotlin.Int declared in <root>.IBase' type=kotlin.Int origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
+              receiver: GET_VAR '<this>: <root>.Test1 declared in <root>.Test1.bar' type=<root>.Test1 origin=null
+    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <> ($this:<root>.Test1) returnType:kotlin.Unit
       overridden:
         public abstract fun qux (): kotlin.Unit declared in <root>.IBase
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase
-      $receiver: VALUE_PARAMETER name:<this> type:kotlin.String
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test1
+      BLOCK_BODY
+        CALL 'public abstract fun qux (): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
+            receiver: GET_VAR '<this>: <root>.Test1 declared in <root>.Test1.qux' type=<root>.Test1 origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
@@ -234,21 +252,111 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Test2 modality:FINAL visibility:public superTypes:[<root>.IBase; <root>.IOther]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IBase, x:kotlin.Int, s:kotlin.String) returnType:kotlin.Unit [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2' type=<root>.Test2 origin=null
+          value: GET_OBJECT 'CLASS OBJECT name:BaseImpl modality:FINAL visibility:public superTypes:[<root>.IBase]' type=<root>.BaseImpl
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_1 type:<root>.IOther visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2' type=<root>.Test2 origin=null
+          value: CALL 'public final fun otherImpl (x0: kotlin.String, y0: kotlin.Int): <root>.IOther declared in <root>' type=<root>.IOther origin=null
+            x0: CONST String type=kotlin.String value=""
+            y0: CONST Int type=kotlin.Int value=42
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.Test2, x:kotlin.Int, s:kotlin.String) returnType:kotlin.Unit
       overridden:
         public abstract fun foo (x: kotlin.Int, s: kotlin.String): kotlin.Unit declared in <root>.IBase
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase
-      VALUE_PARAMETER name:x index:0 type:kotlin.Int
-      VALUE_PARAMETER name:s index:1 type:kotlin.String
-    FUN FAKE_OVERRIDE name:bar visibility:public modality:ABSTRACT <> ($this:<root>.IBase) returnType:kotlin.Int [fake_override]
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+      VALUE_PARAMETER DELEGATED_MEMBER name:x index:0 type:kotlin.Int
+      VALUE_PARAMETER DELEGATED_MEMBER name:s index:1 type:kotlin.String
+      BLOCK_BODY
+        CALL 'public abstract fun foo (x: kotlin.Int, s: kotlin.String): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
+            receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.foo' type=<root>.Test2 origin=null
+          x: GET_VAR 'x: kotlin.Int declared in <root>.Test2.foo' type=kotlin.Int origin=null
+          s: GET_VAR 's: kotlin.String declared in <root>.Test2.foo' type=kotlin.String origin=null
+    FUN DELEGATED_MEMBER name:bar visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.Int
       overridden:
         public abstract fun bar (): kotlin.Int declared in <root>.IBase
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase
-    FUN FAKE_OVERRIDE name:qux visibility:public modality:ABSTRACT <> ($this:<root>.IBase, $receiver:kotlin.String) returnType:kotlin.Unit [fake_override]
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun bar (): kotlin.Int declared in <root>.Test2'
+          CALL 'public abstract fun bar (): kotlin.Int declared in <root>.IBase' type=kotlin.Int origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
+              receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.bar' type=<root>.Test2 origin=null
+    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.Unit
       overridden:
         public abstract fun qux (): kotlin.Unit declared in <root>.IBase
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase
-      $receiver: VALUE_PARAMETER name:<this> type:kotlin.String
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+      BLOCK_BODY
+        CALL 'public abstract fun qux (): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]' type=<root>.IBase origin=null
+            receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.qux' type=<root>.Test2 origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IBase visibility:local [final]
+    PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [val]
+      FUN DELEGATED_MEMBER name:<get-x> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.String
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:x visibility:public modality:OPEN [val]
+        overridden:
+          public abstract fun <get-x> (): kotlin.String declared in <root>.IOther
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-x> (): kotlin.String declared in <root>.Test2'
+            CALL 'public abstract fun <get-x> (): kotlin.String declared in <root>.IOther' type=kotlin.String origin=null
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_1 type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
+                receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<get-x>' type=<root>.Test2 origin=null
+    PROPERTY DELEGATED_MEMBER name:y visibility:public modality:OPEN [var]
+      FUN DELEGATED_MEMBER name:<get-y> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.Int
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:y visibility:public modality:OPEN [var]
+        overridden:
+          public abstract fun <get-y> (): kotlin.Int declared in <root>.IOther
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-y> (): kotlin.Int declared in <root>.Test2'
+            CALL 'public abstract fun <get-y> (): kotlin.Int declared in <root>.IOther' type=kotlin.Int origin=null
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_1 type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
+                receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<get-y>' type=<root>.Test2 origin=null
+      FUN DELEGATED_MEMBER name:<set-y> visibility:public modality:OPEN <> ($this:<root>.Test2, <set-?>:kotlin.Int) returnType:kotlin.Unit
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:y visibility:public modality:OPEN [var]
+        overridden:
+          public abstract fun <set-y> (<set-?>: kotlin.Int): kotlin.Unit declared in <root>.IOther
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        VALUE_PARAMETER DELEGATED_MEMBER name:<set-?> index:0 type:kotlin.Int
+        BLOCK_BODY
+          CALL 'public abstract fun <set-y> (<set-?>: kotlin.Int): kotlin.Unit declared in <root>.IOther' type=kotlin.Unit origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_1 type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
+              receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<set-y>' type=<root>.Test2 origin=null
+            <set-?>: GET_VAR '<set-?>: kotlin.Int declared in <root>.Test2.<set-y>' type=kotlin.Int origin=null
+    PROPERTY DELEGATED_MEMBER name:z1 visibility:public modality:OPEN [val]
+      FUN DELEGATED_MEMBER name:<get-z1> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.Int
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:z1 visibility:public modality:OPEN [val]
+        overridden:
+          public abstract fun <get-z1> (): kotlin.Int declared in <root>.IOther
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-z1> (): kotlin.Int declared in <root>.Test2'
+            CALL 'public abstract fun <get-z1> (): kotlin.Int declared in <root>.IOther' type=kotlin.Int origin=null
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_1 type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
+                receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<get-z1>' type=<root>.Test2 origin=null
+    PROPERTY DELEGATED_MEMBER name:z2 visibility:public modality:OPEN [var]
+      FUN DELEGATED_MEMBER name:<get-z2> visibility:public modality:OPEN <> ($this:<root>.Test2) returnType:kotlin.Int
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:z2 visibility:public modality:OPEN [var]
+        overridden:
+          public abstract fun <get-z2> (): kotlin.Int declared in <root>.IOther
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-z2> (): kotlin.Int declared in <root>.Test2'
+            CALL 'public abstract fun <get-z2> (): kotlin.Int declared in <root>.IOther' type=kotlin.Int origin=null
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_1 type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
+                receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<get-z2>' type=<root>.Test2 origin=null
+      FUN DELEGATED_MEMBER name:<set-z2> visibility:public modality:OPEN <> ($this:<root>.Test2, <set-?>:kotlin.Int) returnType:kotlin.Unit
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:z2 visibility:public modality:OPEN [var]
+        overridden:
+          public abstract fun <set-z2> (<set-?>: kotlin.Int): kotlin.Unit declared in <root>.IOther
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test2
+        VALUE_PARAMETER DELEGATED_MEMBER name:<set-?> index:0 type:kotlin.Int
+        BLOCK_BODY
+          CALL 'public abstract fun <set-z2> (<set-?>: kotlin.Int): kotlin.Unit declared in <root>.IOther' type=kotlin.Unit origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_1 type:<root>.IOther visibility:local [final]' type=<root>.IOther origin=null
+              receiver: GET_VAR '<this>: <root>.Test2 declared in <root>.Test2.<set-z2>' type=<root>.Test2 origin=null
+            <set-?>: GET_VAR '<set-?>: kotlin.Int declared in <root>.Test2.<set-z2>' type=kotlin.Int origin=null
+    FIELD DELEGATE name:$$delegate_1 type:<root>.IOther visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
@@ -262,39 +370,3 @@ FILE fqName:<root> fileName:/delegatedImplementation.kt
       overridden:
         public open fun toString (): kotlin.String declared in kotlin.Any
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
-    PROPERTY FAKE_OVERRIDE name:x visibility:public modality:ABSTRACT [fake_override,val]
-      FUN FAKE_OVERRIDE name:<get-x> visibility:public modality:ABSTRACT <> ($this:<root>.IOther) returnType:kotlin.String [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:x visibility:public modality:ABSTRACT [fake_override,val]
-        overridden:
-          public abstract fun <get-x> (): kotlin.String declared in <root>.IOther
-        $this: VALUE_PARAMETER name:<this> type:<root>.IOther
-    PROPERTY FAKE_OVERRIDE name:y visibility:public modality:ABSTRACT [fake_override,var]
-      FUN FAKE_OVERRIDE name:<get-y> visibility:public modality:ABSTRACT <> ($this:<root>.IOther) returnType:kotlin.Int [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:y visibility:public modality:ABSTRACT [fake_override,var]
-        overridden:
-          public abstract fun <get-y> (): kotlin.Int declared in <root>.IOther
-        $this: VALUE_PARAMETER name:<this> type:<root>.IOther
-      FUN FAKE_OVERRIDE name:<set-y> visibility:public modality:ABSTRACT <> ($this:<root>.IOther, <set-?>:kotlin.Int) returnType:kotlin.Unit [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:y visibility:public modality:ABSTRACT [fake_override,var]
-        overridden:
-          public abstract fun <set-y> (<set-?>: kotlin.Int): kotlin.Unit declared in <root>.IOther
-        $this: VALUE_PARAMETER name:<this> type:<root>.IOther
-        VALUE_PARAMETER name:<set-?> index:0 type:kotlin.Int
-    PROPERTY FAKE_OVERRIDE name:z1 visibility:public modality:ABSTRACT [fake_override,val]
-      FUN FAKE_OVERRIDE name:<get-z1> visibility:public modality:ABSTRACT <> ($this:<root>.IOther) returnType:kotlin.Int [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:z1 visibility:public modality:ABSTRACT [fake_override,val]
-        overridden:
-          public abstract fun <get-z1> (): kotlin.Int declared in <root>.IOther
-        $this: VALUE_PARAMETER name:<this> type:<root>.IOther
-    PROPERTY FAKE_OVERRIDE name:z2 visibility:public modality:ABSTRACT [fake_override,var]
-      FUN FAKE_OVERRIDE name:<get-z2> visibility:public modality:ABSTRACT <> ($this:<root>.IOther) returnType:kotlin.Int [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:z2 visibility:public modality:ABSTRACT [fake_override,var]
-        overridden:
-          public abstract fun <get-z2> (): kotlin.Int declared in <root>.IOther
-        $this: VALUE_PARAMETER name:<this> type:<root>.IOther
-      FUN FAKE_OVERRIDE name:<set-z2> visibility:public modality:ABSTRACT <> ($this:<root>.IOther, <set-?>:kotlin.Int) returnType:kotlin.Unit [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:z2 visibility:public modality:ABSTRACT [fake_override,var]
-        overridden:
-          public abstract fun <set-z2> (<set-?>: kotlin.Int): kotlin.Unit declared in <root>.IOther
-        $this: VALUE_PARAMETER name:<this> type:<root>.IOther
-        VALUE_PARAMETER name:<set-?> index:0 type:kotlin.Int

compiler/testData/ir/irText/classes/delegatedImplementationWithExplicitOverride.fir.txt

@@ -53,15 +53,23 @@ FILE fqName:<root> fileName:/delegatedImplementationWithExplicitOverride.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:C modality:FINAL visibility:public superTypes:[<root>.IFooBar]'
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFooBar visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.C declared in <root>.C' type=<root>.C origin=null
+          value: GET_OBJECT 'CLASS OBJECT name:FooBarImpl modality:FINAL visibility:public superTypes:[<root>.IFooBar]' type=<root>.FooBarImpl
     FUN name:bar visibility:public modality:FINAL <> ($this:<root>.C) returnType:kotlin.Unit
       overridden:
         public abstract fun bar (): kotlin.Unit declared in <root>.IFooBar
       $this: VALUE_PARAMETER name:<this> type:<root>.C
       BLOCK_BODY
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFooBar) returnType:kotlin.Unit [fake_override]
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.C) returnType:kotlin.Unit
       overridden:
         public abstract fun foo (): kotlin.Unit declared in <root>.IFooBar
-      $this: VALUE_PARAMETER name:<this> type:<root>.IFooBar
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.C
+      BLOCK_BODY
+        CALL 'public abstract fun foo (): kotlin.Unit declared in <root>.IFooBar' type=kotlin.Unit origin=null
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFooBar visibility:local [final]' type=<root>.IFooBar origin=null
+            receiver: GET_VAR '<this>: <root>.C declared in <root>.C.foo' type=<root>.C origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IFooBar visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any

compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.fir.txt

@@ -123,10 +123,19 @@ FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestJFoo modality:FINAL visibility:public superTypes:[<root>.IFoo]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.TestJFoo declared in <root>.TestJFoo' type=<root>.TestJFoo origin=null
+          value: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JFoo' type=<root>.JFoo origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestJFoo) returnType:kotlin.String
       overridden:
         public abstract fun foo (): kotlin.String declared in <root>.IFoo
-      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.TestJFoo
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestJFoo'
+          CALL 'public abstract fun foo (): kotlin.String declared in <root>.IFoo' type=kotlin.String origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=<root>.IFoo origin=null
+              receiver: GET_VAR '<this>: <root>.TestJFoo declared in <root>.TestJFoo.foo' type=<root>.TestJFoo origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
@@ -146,10 +155,19 @@ FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK1 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.TestK1 declared in <root>.TestK1' type=<root>.TestK1 origin=null
+          value: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.K1' type=<root>.K1 origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestK1) returnType:kotlin.String
       overridden:
         public abstract fun foo (): kotlin.String declared in <root>.IFoo
-      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.TestK1
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestK1'
+          CALL 'public abstract fun foo (): kotlin.String declared in <root>.IFoo' type=kotlin.String origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=<root>.IFoo origin=null
+              receiver: GET_VAR '<this>: <root>.TestK1 declared in <root>.TestK1.foo' type=<root>.TestK1 origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
@@ -169,10 +187,19 @@ FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK2 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.TestK2 declared in <root>.TestK2' type=<root>.TestK2 origin=null
+          value: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.K2' type=<root>.K2 origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestK2) returnType:kotlin.String
       overridden:
         public abstract fun foo (): kotlin.String declared in <root>.IFoo
-      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.TestK2
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestK2'
+          CALL 'public abstract fun foo (): kotlin.String declared in <root>.IFoo' type=kotlin.String origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=<root>.IFoo origin=null
+              receiver: GET_VAR '<this>: <root>.TestK2 declared in <root>.TestK2.foo' type=<root>.TestK2 origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
@@ -192,10 +219,19 @@ FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK3 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.TestK3 declared in <root>.TestK3' type=<root>.TestK3 origin=null
+          value: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.K3' type=<root>.K3 origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestK3) returnType:kotlin.String
       overridden:
         public abstract fun foo (): kotlin.String declared in <root>.IFoo
-      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.TestK3
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestK3'
+          CALL 'public abstract fun foo (): kotlin.String declared in <root>.IFoo' type=kotlin.String origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=<root>.IFoo origin=null
+              receiver: GET_VAR '<this>: <root>.TestK3 declared in <root>.TestK3.foo' type=<root>.TestK3 origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
@@ -215,10 +251,19 @@ FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:TestK4 modality:FINAL visibility:public superTypes:[<root>.IFoo]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IFoo) returnType:kotlin.String [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.TestK4 declared in <root>.TestK4' type=<root>.TestK4 origin=null
+          value: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.K4' type=<root>.K4 origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.TestK4) returnType:kotlin.String
       overridden:
         public abstract fun foo (): kotlin.String declared in <root>.IFoo
-      $this: VALUE_PARAMETER name:<this> type:<root>.IFoo
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.TestK4
+      BLOCK_BODY
+        RETURN type=kotlin.Nothing from='public open fun foo (): kotlin.String declared in <root>.TestK4'
+          CALL 'public abstract fun foo (): kotlin.String declared in <root>.IFoo' type=kotlin.String origin=null
+            $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]' type=<root>.IFoo origin=null
+              receiver: GET_VAR '<this>: <root>.TestK4 declared in <root>.TestK4.foo' type=<root>.TestK4 origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IFoo visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any

compiler/testData/ir/irText/declarations/kt35550.fir.txt

@@ -30,12 +30,22 @@ FILE fqName:<root> fileName:/kt35550.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:A modality:FINAL visibility:public superTypes:[<root>.I]'
-    PROPERTY FAKE_OVERRIDE name:id visibility:public modality:OPEN [fake_override,val]
-      FUN FAKE_OVERRIDE name:<get-id> visibility:public modality:OPEN <> ($this:<root>.I) returnType:T of <root>.I.<get-id> [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:id visibility:public modality:OPEN [fake_override,val]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.I visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.A declared in <root>.A' type=<root>.A origin=null
+          value: GET_VAR 'i: <root>.I declared in <root>.A.<init>' type=<root>.I origin=null
+    PROPERTY DELEGATED_MEMBER name:id visibility:public modality:OPEN [val]
+      FUN DELEGATED_MEMBER name:<get-id> visibility:public modality:OPEN <> ($this:<root>.A) returnType:T of <root>.I.<get-id>
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:id visibility:public modality:OPEN [val]
         overridden:
           public open fun <get-id> <T> (): T of <root>.I.<get-id> declared in <root>.I
-        $this: VALUE_PARAMETER name:<this> type:<root>.I
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.A
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-id> (): T of <root>.I.<get-id> declared in <root>.A'
+            CALL 'public open fun <get-id> <T> (): T of <root>.I.<get-id> declared in <root>.I' type=T of <root>.I.<get-id> origin=null
+              <T>: <none>
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.I visibility:local [final]' type=<root>.I origin=null
+                receiver: GET_VAR '<this>: <root>.A declared in <root>.A.<get-id>' type=<root>.A origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.I visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any

compiler/testData/ir/irText/declarations/parameters/delegatedMembers.fir.txt

@@ -35,24 +35,44 @@ FILE fqName:<root> fileName:/delegatedMembers.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in kotlin.Any'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Test modality:FINAL visibility:public superTypes:[<root>.IBase<TT of <root>.Test>]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:ABSTRACT <> ($this:<root>.IBase<T of <root>.IBase>, x:kotlin.Int) returnType:kotlin.Unit [fake_override]
+        SET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<TT of <root>.Test> visibility:local [final]' type=kotlin.Unit origin=EQ
+          receiver: GET_VAR '<this>: <root>.Test<TT of <root>.Test> declared in <root>.Test' type=<root>.Test<TT of <root>.Test> origin=null
+          value: GET_VAR 'impl: <root>.IBase<TT of <root>.Test> declared in <root>.Test.<init>' type=<root>.IBase<TT of <root>.Test> origin=null
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:<root>.Test<TT of <root>.Test>, x:kotlin.Int) returnType:kotlin.Unit
       overridden:
         public abstract fun foo (x: kotlin.Int): kotlin.Unit declared in <root>.IBase
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase<T of <root>.IBase>
-      VALUE_PARAMETER name:x index:0 type:kotlin.Int
-    PROPERTY FAKE_OVERRIDE name:bar visibility:public modality:ABSTRACT [fake_override,val]
-      FUN FAKE_OVERRIDE name:<get-bar> visibility:public modality:ABSTRACT <> ($this:<root>.IBase<T of <root>.IBase>) returnType:kotlin.Int [fake_override]
-        correspondingProperty: PROPERTY FAKE_OVERRIDE name:bar visibility:public modality:ABSTRACT [fake_override,val]
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test<TT of <root>.Test>
+      VALUE_PARAMETER DELEGATED_MEMBER name:x index:0 type:kotlin.Int
+      BLOCK_BODY
+        CALL 'public abstract fun foo (x: kotlin.Int): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<TT of <root>.Test> visibility:local [final]' type=<root>.IBase<TT of <root>.Test> origin=null
+            receiver: GET_VAR '<this>: <root>.Test<TT of <root>.Test> declared in <root>.Test.foo' type=<root>.Test<TT of <root>.Test> origin=null
+          x: GET_VAR 'x: kotlin.Int declared in <root>.Test.foo' type=kotlin.Int origin=null
+    PROPERTY DELEGATED_MEMBER name:bar visibility:public modality:OPEN [val]
+      FUN DELEGATED_MEMBER name:<get-bar> visibility:public modality:OPEN <> ($this:<root>.Test<TT of <root>.Test>) returnType:kotlin.Int
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:bar visibility:public modality:OPEN [val]
         overridden:
           public abstract fun <get-bar> (): kotlin.Int declared in <root>.IBase
-        $this: VALUE_PARAMETER name:<this> type:<root>.IBase<T of <root>.IBase>
-    FUN FAKE_OVERRIDE name:qux visibility:public modality:ABSTRACT <X> ($this:<root>.IBase<T of <root>.IBase>, t:TT of <root>.Test, x:X of <root>.Test.qux) returnType:kotlin.Unit [fake_override]
+        $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test<TT of <root>.Test>
+        BLOCK_BODY
+          RETURN type=kotlin.Nothing from='public open fun <get-bar> (): kotlin.Int declared in <root>.Test'
+            CALL 'public abstract fun <get-bar> (): kotlin.Int declared in <root>.IBase' type=kotlin.Int origin=null
+              $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<TT of <root>.Test> visibility:local [final]' type=<root>.IBase<TT of <root>.Test> origin=null
+                receiver: GET_VAR '<this>: <root>.Test<TT of <root>.Test> declared in <root>.Test.<get-bar>' type=<root>.Test<TT of <root>.Test> origin=null
+    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <> ($this:<root>.Test<TT of <root>.Test>, t:T of <root>.IBase, x:X of <root>.IBase.qux) returnType:kotlin.Unit
       overridden:
         public abstract fun qux <X> (t: T of <root>.IBase, x: X of <root>.IBase.qux): kotlin.Unit declared in <root>.IBase
-      TYPE_PARAMETER name:X index:0 variance: superTypes:[kotlin.Any?]
-      $this: VALUE_PARAMETER name:<this> type:<root>.IBase<T of <root>.IBase>
-      VALUE_PARAMETER name:t index:0 type:TT of <root>.Test
-      VALUE_PARAMETER name:x index:1 type:X of <root>.Test.qux
+      $this: VALUE_PARAMETER DELEGATED_MEMBER name:<this> type:<root>.Test<TT of <root>.Test>
+      VALUE_PARAMETER DELEGATED_MEMBER name:t index:0 type:T of <root>.IBase
+      VALUE_PARAMETER DELEGATED_MEMBER name:x index:1 type:X of <root>.IBase.qux
+      BLOCK_BODY
+        CALL 'public abstract fun qux <X> (t: T of <root>.IBase, x: X of <root>.IBase.qux): kotlin.Unit declared in <root>.IBase' type=kotlin.Unit origin=null
+          <X>: <none>
+          $this: GET_FIELD 'FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<TT of <root>.Test> visibility:local [final]' type=<root>.IBase<TT of <root>.Test> origin=null
+            receiver: GET_VAR '<this>: <root>.Test<TT of <root>.Test> declared in <root>.Test.qux' type=<root>.Test<TT of <root>.Test> origin=null
+          t: GET_VAR 't: T of <root>.IBase declared in <root>.Test.qux' type=T of <root>.IBase origin=null
+          x: GET_VAR 'x: X of <root>.IBase.qux declared in <root>.Test.qux' type=X of <root>.IBase.qux origin=null
+    FIELD DELEGATE name:$$delegate_0 type:<root>.IBase<TT of <root>.Test> visibility:local [final]
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any