Partially revert "Persistent IR implementation"

This partially reverts commit f437da8ee5.
Changes related to carriers and others are still there. They will be
moved out to a separate module in a subsequent commit.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrAnonymousInitializerImpl.kt

@@ -20,7 +20,6 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrAnonymousInitializer
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.AnonymousInitializerCarrier
 import org.jetbrains.kotlin.ir.expressions.IrBlockBody
 import org.jetbrains.kotlin.ir.symbols.IrAnonymousInitializerSymbol
 
@@ -30,10 +29,7 @@ class IrAnonymousInitializerImpl(
     origin: IrDeclarationOrigin,
     override val symbol: IrAnonymousInitializerSymbol,
     override val isStatic: Boolean = false
-) : IrDeclarationBase<AnonymousInitializerCarrier>(startOffset, endOffset, origin),
-    IrAnonymousInitializer,
-    AnonymousInitializerCarrier {
-
+) : IrDeclarationBase(startOffset, endOffset, origin), IrAnonymousInitializer {
     init {
         symbol.bind(this)
     }
@@ -42,16 +38,5 @@ class IrAnonymousInitializerImpl(
     override val descriptor: ClassDescriptor
         get() = symbol.descriptor
 
-    override var bodyField: IrBlockBody? = null
-
-    override var body: IrBlockBody
-        get() = getCarrier().bodyField!!
-        set(v) {
-            if (getCarrier().bodyField !== v) {
-                if (v is IrBodyBase<*>) {
-                    v.container = this
-                }
-                setCarrier().bodyField = v
-            }
-        }
+    override lateinit var body: IrBlockBody
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrClassImpl.kt

@@ -19,12 +19,9 @@ package org.jetbrains.kotlin.ir.declarations.impl
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.ClassCarrier
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.name.Name
-import java.util.*
-import kotlin.collections.ArrayList
 
 class IrClassImpl(
     startOffset: Int,
@@ -33,8 +30,8 @@ class IrClassImpl(
     override val symbol: IrClassSymbol,
     override val name: Name,
     override val kind: ClassKind,
-    visibility: Visibility,
-    modality: Modality,
+    override var visibility: Visibility,
+    override var modality: Modality,
     override val isCompanion: Boolean = false,
     override val isInner: Boolean = false,
     override val isData: Boolean = false,
@@ -43,11 +40,7 @@ class IrClassImpl(
     override val isExpect: Boolean = false,
     override val isFun: Boolean = false,
     override val source: SourceElement = SourceElement.NO_SOURCE
-) :
-    IrDeclarationBase<ClassCarrier>(startOffset, endOffset, origin),
-    IrClass,
-    ClassCarrier {
-
+) : IrDeclarationBase(startOffset, endOffset, origin), IrClass {
     init {
         symbol.bind(this)
     }
@@ -56,89 +49,15 @@ class IrClassImpl(
     override val descriptor: ClassDescriptor
         get() = symbol.descriptor
 
-    override var visibilityField: Visibility = visibility
-
-    override var visibility: Visibility
-        get() = getCarrier().visibilityField
-        set(v) {
-            if (visibility !== v) {
-                setCarrier().visibilityField = v
-            }
-        }
-
-    override var thisReceiverField: IrValueParameter? = null
-
-    override var thisReceiver: IrValueParameter?
-        get() = getCarrier().thisReceiverField
-        set(v) {
-            if (thisReceiver !== v) {
-                setCarrier().thisReceiverField = v
-            }
-        }
-
-    private var initialDeclarations: MutableList<IrDeclaration>? = null
+    override var thisReceiver: IrValueParameter? = null
 
     override val declarations: MutableList<IrDeclaration> = ArrayList()
-        get() {
-            if (createdOn < stageController.currentStage && initialDeclarations == null) {
-                initialDeclarations = Collections.unmodifiableList(ArrayList(field))
-            }
 
-            return if (stageController.canAccessDeclarationsOf(this)) {
-                ensureLowered()
-                field
-            } else {
-                initialDeclarations ?: field
-            }
-        }
+    override var typeParameters: List<IrTypeParameter> = emptyList()
 
-    override var typeParametersField: List<IrTypeParameter> = emptyList()
+    override var superTypes: List<IrType> = emptyList()
 
-    override var typeParameters: List<IrTypeParameter>
-        get() = getCarrier().typeParametersField
-        set(v) {
-            if (typeParameters !== v) {
-                setCarrier().typeParametersField = v
-            }
-        }
+    override var metadata: MetadataSource? = null
 
-    override var superTypesField: List<IrType> = emptyList()
-
-    override var superTypes: List<IrType>
-        get() = getCarrier().superTypesField
-        set(v) {
-            if (superTypes !== v) {
-                setCarrier().superTypesField = v
-            }
-        }
-
-    override var metadataField: MetadataSource? = null
-
-    override var metadata: MetadataSource?
-        get() = getCarrier().metadataField
-        set(v) {
-            if (metadata !== v) {
-                setCarrier().metadataField = v
-            }
-        }
-
-    override var modalityField: Modality = modality
-
-    override var modality: Modality
-        get() = getCarrier().modalityField
-        set(v) {
-            if (modality !== v) {
-                setCarrier().modalityField = v
-            }
-        }
-
-    override var attributeOwnerIdField: IrAttributeContainer = this
-
-    override var attributeOwnerId: IrAttributeContainer
-        get() = getCarrier().attributeOwnerIdField
-        set(v) {
-            if (attributeOwnerId !== v) {
-                setCarrier().attributeOwnerIdField = v
-            }
-        }
+    override var attributeOwnerId: IrAttributeContainer = this
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrConstructorImpl.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrConstructor
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.ConstructorCarrier
 import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.name.Name
@@ -38,16 +37,7 @@ class IrConstructorImpl(
     isExternal: Boolean,
     override val isPrimary: Boolean,
     isExpect: Boolean
-) :
-    IrFunctionBase<ConstructorCarrier>(
-        startOffset, endOffset, origin, name,
-        visibility,
-        isInline, isExternal, isExpect,
-        returnType
-    ),
-    IrConstructor,
-    ConstructorCarrier {
-
+) : IrFunctionBase(startOffset, endOffset, origin, name, visibility, isInline, isExternal, isExpect, returnType), IrConstructor {
     init {
         symbol.bind(this)
     }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrDeclarationBase.kt

@@ -17,170 +17,27 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.ir.IrElementBase
-import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.BodyCarrier
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.Carrier
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.DeclarationCarrier
-import org.jetbrains.kotlin.ir.expressions.IrBody
+import org.jetbrains.kotlin.ir.declarations.IrDeclaration
+import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
+import org.jetbrains.kotlin.ir.declarations.IrDeclarationParent
+import org.jetbrains.kotlin.ir.declarations.IrFactory
 import org.jetbrains.kotlin.ir.expressions.IrConstructorCall
 
-abstract class IrDeclarationBase<T : DeclarationCarrier>(
+abstract class IrDeclarationBase(
     startOffset: Int,
     endOffset: Int,
-    origin: IrDeclarationOrigin
-) : IrPersistingElementBase<T>(startOffset, endOffset),
-    IrDeclaration,
-    DeclarationCarrier {
-
+    override var origin: IrDeclarationOrigin
+) : IrElementBase(startOffset, endOffset), IrDeclaration {
     override val factory: IrFactory
         get() = IrFactoryImpl
 
-    override var parentField: IrDeclarationParent? = null
-
-    // TODO reduce boilerplate
+    private var _parent: IrDeclarationParent? = null
     override var parent: IrDeclarationParent
-        get() = getCarrier().parentField ?: throw UninitializedPropertyAccessException("Parent not initialized: $this")
-        set(p) {
-            if (getCarrier().parentField !== p) {
-                setCarrier().parentField = p
-            }
-        }
-
-    override var originField: IrDeclarationOrigin = origin
-
-    override var origin: IrDeclarationOrigin
-        get() = getCarrier().originField
-        set(p) {
-            if (getCarrier().originField !== p) {
-                setCarrier().originField = p
-            }
-        }
-
-    var removedOn: Int = Int.MAX_VALUE
-
-    override var annotationsField: List<IrConstructorCall> = emptyList()
-
-    override var annotations: List<IrConstructorCall>
-        get() = getCarrier().annotationsField
+        get() = _parent
+            ?: throw UninitializedPropertyAccessException("Parent not initialized: $this")
         set(v) {
-            if (getCarrier().annotationsField !== v) {
-                setCarrier().annotationsField = v
-            }
+            _parent = v
         }
 
-    override fun ensureLowered() {
-        if (stageController.currentStage > loweredUpTo) {
-            stageController.lazyLower(this)
-        }
-    }
+    override var annotations: List<IrConstructorCall> = emptyList()
 }
-
-abstract class IrPersistingElementBase<T : Carrier>(
-    startOffset: Int,
-    endOffset: Int
-) : IrElementBase(startOffset, endOffset),
-    Carrier {
-
-    override var lastModified: Int = stageController.currentStage
-
-    var loweredUpTo = stageController.currentStage
-
-    // TODO Array<T>?
-    private var values: Array<Carrier>? = null
-
-    val createdOn: Int = stageController.currentStage
-//        get() = values?.let { (it[0] as T).lastModified } ?: lastModified
-
-    abstract fun ensureLowered()
-
-    protected fun getCarrier(): T {
-        stageController.currentStage.let { stage ->
-            ensureLowered()
-
-            if (stage >= lastModified) return this as T
-
-            if (stage < createdOn) error("Access before creation")
-
-            val v = values
-                ?: error("How come?")
-
-            var l = -1
-            var r = v.size
-            while (r - l > 1) {
-                val m = (l + r) / 2
-                if ((v[m] as T).lastModified <= stage) {
-                    l = m
-                } else {
-                    r = m
-                }
-            }
-            if (l < 0) {
-                error("access before creation")
-            }
-
-            return v[l] as T
-        }
-    }
-
-    // TODO naming? e.g. `mutableCarrier`
-    protected fun setCarrier(): T {
-        val stage = stageController.currentStage
-
-        ensureLowered()
-
-        if (!stageController.canModify(this)) {
-            error("Cannot modify this element!")
-        }
-
-        if (loweredUpTo > stage) {
-            error("retrospective modification")
-        }
-
-        // TODO move up? i.e. fast path
-        if (stage == lastModified) {
-            return this as T
-        } else {
-            values = (values ?: emptyArray()) + this.clone() as T
-        }
-
-        this.lastModified = stage
-
-        return this as T
-    }
-}
-
-abstract class IrBodyBase<B : IrBodyBase<B>>(
-    startOffset: Int,
-    endOffset: Int,
-    private var initializer: (B.() -> Unit)?
-) : IrPersistingElementBase<BodyCarrier>(startOffset, endOffset), IrBody, BodyCarrier {
-    override var containerField: IrDeclaration? = null
-
-    var container: IrDeclaration
-        get() = getCarrier().containerField!!
-        set(p) {
-            if (getCarrier().containerField !== p) {
-                setCarrier().containerField = p
-            }
-        }
-
-    protected fun <T> checkEnabled(fn: () -> T): T {
-        if (!stageController.bodiesEnabled) error("Bodies disabled!")
-        ensureLowered()
-        return fn()
-    }
-
-    override fun ensureLowered() {
-        initializer?.let { initFn ->
-            initializer = null
-            stageController.withStage(createdOn) {
-                stageController.bodyLowering {
-                    initFn.invoke(this as B)
-                }
-            }
-        }
-        if (loweredUpTo + 1 < stageController.currentStage) {
-            stageController.lazyLower(this)
-        }
-    }
-}

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrEnumEntryImpl.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrEnumEntry
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.EnumEntryCarrier
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.symbols.IrEnumEntrySymbol
 import org.jetbrains.kotlin.name.Name
@@ -32,10 +31,7 @@ class IrEnumEntryImpl(
     origin: IrDeclarationOrigin,
     override val symbol: IrEnumEntrySymbol,
     override val name: Name
-) : IrDeclarationBase<EnumEntryCarrier>(startOffset, endOffset, origin),
-    IrEnumEntry,
-    EnumEntryCarrier {
-
+) : IrDeclarationBase(startOffset, endOffset, origin), IrEnumEntry {
     init {
         symbol.bind(this)
     }
@@ -44,26 +40,6 @@ class IrEnumEntryImpl(
     override val descriptor: ClassDescriptor
         get() = symbol.descriptor
 
-    override var correspondingClassField: IrClass? = null
-
-    override var correspondingClass: IrClass?
-        get() = getCarrier().correspondingClassField
-        set(v) {
-            if (correspondingClass !== v) {
-                setCarrier().correspondingClassField = v
-            }
-        }
-
-    override var initializerExpressionField: IrExpressionBody? = null
-
-    override var initializerExpression: IrExpressionBody?
-        get() = getCarrier().initializerExpressionField
-        set(v) {
-            if (initializerExpression !== v) {
-                if (v is IrBodyBase<*>) {
-                    v.container = this
-                }
-                setCarrier().initializerExpressionField = v
-            }
-        }
+    override var correspondingClass: IrClass? = null
+    override var initializerExpression: IrExpressionBody? = null
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrErrorDeclarationImpl.kt

@@ -20,11 +20,10 @@ import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrErrorDeclaration
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.ErrorCarrier
 
 @OptIn(ObsoleteDescriptorBasedAPI::class)
 class IrErrorDeclarationImpl(
     startOffset: Int,
     endOffset: Int,
     override val descriptor: DeclarationDescriptor
-) : IrDeclarationBase<ErrorCarrier>(startOffset, endOffset, IrDeclarationOrigin.DEFINED), IrErrorDeclaration, ErrorCarrier
+) : IrDeclarationBase(startOffset, endOffset, IrDeclarationOrigin.DEFINED), IrErrorDeclaration

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFactoryImpl.kt

@@ -252,7 +252,7 @@ object IrFactoryImpl : IrFactory {
         startOffset: Int,
         endOffset: Int,
     ): IrBlockBody =
-        IrBlockBodyImpl(startOffset, endOffset, null)
+        IrBlockBodyImpl(startOffset, endOffset)
 
     override fun createBlockBody(
         startOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFieldImpl.kt

@@ -22,7 +22,6 @@ import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.MetadataSource
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.FieldCarrier
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
 import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
@@ -39,11 +38,8 @@ class IrFieldImpl(
     override var visibility: Visibility,
     override val isFinal: Boolean,
     override val isExternal: Boolean,
-    override val isStatic: Boolean
-) : IrDeclarationBase<FieldCarrier>(startOffset, endOffset, origin),
-    IrField,
-    FieldCarrier {
-
+    override val isStatic: Boolean,
+) : IrDeclarationBase(startOffset, endOffset, origin), IrField {
     init {
         symbol.bind(this)
     }
@@ -52,36 +48,9 @@ class IrFieldImpl(
     override val descriptor: PropertyDescriptor
         get() = symbol.descriptor
 
-    override var initializerField: IrExpressionBody? = null
+    override var initializer: IrExpressionBody? = null
 
-    override var initializer: IrExpressionBody?
-        get() = getCarrier().initializerField
-        set(v) {
-            if (initializer !== v) {
-                if (v is IrBodyBase<*>) {
-                    v.container = this
-                }
-                setCarrier().initializerField = v
-            }
-        }
+    override var correspondingPropertySymbol: IrPropertySymbol? = null
 
-    override var correspondingPropertySymbolField: IrPropertySymbol? = null
-
-    override var correspondingPropertySymbol: IrPropertySymbol?
-        get() = getCarrier().correspondingPropertySymbolField
-        set(v) {
-            if (correspondingPropertySymbol !== v) {
-                setCarrier().correspondingPropertySymbolField = v
-            }
-        }
-
-    override var metadataField: MetadataSource? = null
-
-    override var metadata: MetadataSource?
-        get() = getCarrier().metadataField
-        set(v) {
-            if (metadata !== v) {
-                setCarrier().metadataField = v
-            }
-        }
+    override var metadata: MetadataSource? = null
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFileImpl.kt

@@ -52,7 +52,7 @@ class IrFileImpl(
 
     override val declarations: MutableList<IrDeclaration> = ArrayList()
 
-    override var annotations: List<IrConstructorCall> = ArrayList()
+    override var annotations: List<IrConstructorCall> = emptyList()
 
     override var metadata: MetadataSource? = null
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFunctionBase.kt

@@ -18,116 +18,36 @@ package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.FunctionBaseCarrier
 import org.jetbrains.kotlin.ir.expressions.IrBody
 import org.jetbrains.kotlin.ir.types.IrType
-import org.jetbrains.kotlin.ir.types.impl.IrUninitializedType
 import org.jetbrains.kotlin.name.Name
 
-abstract class IrFunctionBase<T : FunctionBaseCarrier>(
+abstract class IrFunctionBase(
     startOffset: Int,
     endOffset: Int,
     origin: IrDeclarationOrigin,
     override val name: Name,
-    visibility: Visibility,
+    override var visibility: Visibility,
     override val isInline: Boolean,
     override val isExternal: Boolean,
     override val isExpect: Boolean,
     returnType: IrType
-) :
-    IrDeclarationBase<T>(startOffset, endOffset, origin),
-    IrFunction,
-    FunctionBaseCarrier {
-
-    override var returnTypeFieldField: IrType = returnType
-
-    private var returnTypeField: IrType
-        get() = getCarrier().returnTypeFieldField
-        set(v) {
-            if (returnTypeField !== v) {
-                setCarrier().returnTypeFieldField = v
-            }
-        }
-
+) : IrDeclarationBase(startOffset, endOffset, origin), IrFunction {
     @Suppress("DEPRECATION")
-    final override var returnType: IrType
-        get() = returnTypeField.let {
-            if (it !== IrUninitializedType) it else error("Return type is not initialized")
-        }
-        set(c) {
-            returnTypeField = c
+    final override var returnType: IrType = returnType
+        get() = if (field === org.jetbrains.kotlin.ir.types.impl.IrUninitializedType) {
+            error("Return type is not initialized")
+        } else {
+            field
         }
 
-    override var typeParametersField: List<IrTypeParameter> = emptyList()
+    override var typeParameters: List<IrTypeParameter> = emptyList()
 
-    override var typeParameters: List<IrTypeParameter>
-        get() = getCarrier().typeParametersField
-        set(v) {
-            if (typeParameters !== v) {
-                setCarrier().typeParametersField = v
-            }
-        }
+    override var dispatchReceiverParameter: IrValueParameter? = null
+    override var extensionReceiverParameter: IrValueParameter? = null
+    override var valueParameters: List<IrValueParameter> = emptyList()
 
-    override var dispatchReceiverParameterField: IrValueParameter? = null
+    final override var body: IrBody? = null
 
-    override var dispatchReceiverParameter: IrValueParameter?
-        get() = getCarrier().dispatchReceiverParameterField
-        set(v) {
-            if (dispatchReceiverParameter !== v) {
-                setCarrier().dispatchReceiverParameterField = v
-            }
-        }
-
-    override var extensionReceiverParameterField: IrValueParameter? = null
-
-    override var extensionReceiverParameter: IrValueParameter?
-        get() = getCarrier().extensionReceiverParameterField
-        set(v) {
-            if (extensionReceiverParameter !== v) {
-                setCarrier().extensionReceiverParameterField = v
-            }
-        }
-
-    override var valueParametersField: List<IrValueParameter> = emptyList()
-
-    override var valueParameters: List<IrValueParameter>
-        get() = getCarrier().valueParametersField
-        set(v) {
-            if (valueParameters !== v) {
-                setCarrier().valueParametersField = v
-            }
-        }
-
-    override var bodyField: IrBody? = null
-
-    final override var body: IrBody?
-        get() = getCarrier().bodyField
-        set(v) {
-            if (body !== v) {
-                if (v is IrBodyBase<*>) {
-                    v.container = this
-                }
-                setCarrier().bodyField = v
-            }
-        }
-
-    override var metadataField: MetadataSource? = null
-
-    override var metadata: MetadataSource?
-        get() = getCarrier().metadataField
-        set(v) {
-            if (metadata !== v) {
-                setCarrier().metadataField = v
-            }
-        }
-
-    override var visibilityField: Visibility = visibility
-
-    override var visibility: Visibility
-        get() = getCarrier().visibilityField
-        set(v) {
-            if (visibility !== v) {
-                setCarrier().visibilityField = v
-            }
-        }
+    override var metadata: MetadataSource? = null
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFunctionImpl.kt

@@ -13,7 +13,6 @@ import org.jetbrains.kotlin.ir.declarations.IrAttributeContainer
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrFakeOverrideFunction
 import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.FunctionCarrier
 import org.jetbrains.kotlin.ir.descriptors.WrappedSimpleFunctionDescriptor
 import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
@@ -34,44 +33,13 @@ abstract class IrFunctionCommonImpl(
     override val isOperator: Boolean,
     override val isInfix: Boolean,
     isExpect: Boolean,
-) :
-    IrFunctionBase<FunctionCarrier>(startOffset, endOffset, origin, name, visibility, isInline, isExternal, isExpect, returnType),
-    IrSimpleFunction,
-    FunctionCarrier {
-
-    @ObsoleteDescriptorBasedAPI
-    abstract override val descriptor: FunctionDescriptor
-
-    override var overriddenSymbolsField: List<IrSimpleFunctionSymbol> = emptyList()
-
-    override var overriddenSymbols: List<IrSimpleFunctionSymbol>
-        get() = getCarrier().overriddenSymbolsField
-        set(v) {
-            if (overriddenSymbols !== v) {
-                setCarrier().overriddenSymbolsField = v
-            }
-        }
+) : IrFunctionBase(startOffset, endOffset, origin, name, visibility, isInline, isExternal, isExpect, returnType), IrSimpleFunction {
+    override var overriddenSymbols: List<IrSimpleFunctionSymbol> = emptyList()
 
     @Suppress("LeakingThis")
-    override var attributeOwnerIdField: IrAttributeContainer = this
+    override var attributeOwnerId: IrAttributeContainer = this
 
-    override var attributeOwnerId: IrAttributeContainer
-        get() = getCarrier().attributeOwnerIdField
-        set(v) {
-            if (attributeOwnerId !== v) {
-                setCarrier().attributeOwnerIdField = v
-            }
-        }
-
-    override var correspondingPropertySymbolField: IrPropertySymbol? = null
-
-    override var correspondingPropertySymbol: IrPropertySymbol?
-        get() = getCarrier().correspondingPropertySymbolField
-        set(v) {
-            if (correspondingPropertySymbol !== v) {
-                setCarrier().correspondingPropertySymbolField = v
-            }
-        }
+    override var correspondingPropertySymbol: IrPropertySymbol? = null
 }
 
 class IrFunctionImpl(

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrLocalDelegatedPropertyImpl.kt

@@ -19,12 +19,10 @@ package org.jetbrains.kotlin.ir.declarations.impl
 import org.jetbrains.kotlin.descriptors.VariableDescriptorWithAccessors
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.LocalDelegatedPropertyCarrier
 import org.jetbrains.kotlin.ir.symbols.IrLocalDelegatedPropertySymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.name.Name
 
-// TODO make not persistent
 class IrLocalDelegatedPropertyImpl(
     startOffset: Int,
     endOffset: Int,
@@ -33,11 +31,7 @@ class IrLocalDelegatedPropertyImpl(
     override val name: Name,
     override val type: IrType,
     override val isVar: Boolean
-) :
-    IrDeclarationBase<LocalDelegatedPropertyCarrier>(startOffset, endOffset, origin),
-    IrLocalDelegatedProperty,
-    LocalDelegatedPropertyCarrier {
-
+) : IrDeclarationBase(startOffset, endOffset, origin), IrLocalDelegatedProperty {
     init {
         symbol.bind(this)
     }
@@ -46,43 +40,11 @@ class IrLocalDelegatedPropertyImpl(
     override val descriptor: VariableDescriptorWithAccessors
         get() = symbol.descriptor
 
-    override var delegateField: IrVariable? = null
+    override lateinit var delegate: IrVariable
 
-    override var delegate: IrVariable
-        get() = getCarrier().delegateField!!
-        set(v) {
-            if (getCarrier().delegateField !== v) {
-                setCarrier().delegateField = v
-            }
-        }
+    override lateinit var getter: IrFunction
 
-    override var getterField: IrFunction? = null
+    override var setter: IrFunction? = null
 
-    override var getter: IrFunction
-        get() = getCarrier().getterField!!
-        set(v) {
-            if (getCarrier().getterField !== v) {
-                setCarrier().getterField = v
-            }
-        }
-
-    override var setterField: IrFunction? = null
-
-    override var setter: IrFunction?
-        get() = getCarrier().setterField
-        set(v) {
-            if (setter !== v) {
-                setCarrier().setterField = v
-            }
-        }
-
-    override var metadataField: MetadataSource? = null
-
-    override var metadata: MetadataSource?
-        get() = getCarrier().metadataField
-        set(v) {
-            if (metadata !== v) {
-                setCarrier().metadataField = v
-            }
-        }
+    override var metadata: MetadataSource? = null
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrPropertyImpl.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.PropertyCarrier
 import org.jetbrains.kotlin.ir.descriptors.WrappedPropertyDescriptor
 import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
 import org.jetbrains.kotlin.name.Name
@@ -38,52 +37,14 @@ abstract class IrPropertyCommonImpl(
     override val isDelegated: Boolean,
     override val isExternal: Boolean,
     override val isExpect: Boolean,
-) : IrDeclarationBase<PropertyCarrier>(startOffset, endOffset, origin),
-    IrProperty,
-    PropertyCarrier {
+) : IrDeclarationBase(startOffset, endOffset, origin), IrProperty {
+    override var backingField: IrField? = null
 
-    @ObsoleteDescriptorBasedAPI
-    abstract override val descriptor: PropertyDescriptor
+    override var getter: IrSimpleFunction? = null
 
-    override var backingFieldField: IrField? = null
+    override var setter: IrSimpleFunction? = null
 
-    override var backingField: IrField?
-        get() = getCarrier().backingFieldField
-        set(v) {
-            if (backingField !== v) {
-                setCarrier().backingFieldField = v
-            }
-        }
-
-    override var getterField: IrSimpleFunction? = null
-
-    override var getter: IrSimpleFunction?
-        get() = getCarrier().getterField
-        set(v) {
-            if (getter !== v) {
-                setCarrier().getterField = v
-            }
-        }
-
-    override var setterField: IrSimpleFunction? = null
-
-    override var setter: IrSimpleFunction?
-        get() = getCarrier().setterField
-        set(v) {
-            if (setter !== v) {
-                setCarrier().setterField = v
-            }
-        }
-
-    override var metadataField: MetadataSource? = null
-
-    override var metadata: MetadataSource?
-        get() = getCarrier().metadataField
-        set(v) {
-            if (metadata !== v) {
-                setCarrier().metadataField = v
-            }
-        }
+    override var metadata: MetadataSource? = null
 }
 
 class IrPropertyImpl(

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeAliasImpl.kt

@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrTypeAlias
 import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.TypeAliasCarrier
 import org.jetbrains.kotlin.ir.symbols.IrTypeAliasSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.name.Name
@@ -25,11 +24,7 @@ class IrTypeAliasImpl(
     override val expandedType: IrType,
     override val isActual: Boolean,
     origin: IrDeclarationOrigin
-) :
-    IrDeclarationBase<TypeAliasCarrier>(startOffset, endOffset, origin),
-    IrTypeAlias,
-    TypeAliasCarrier {
-
+) : IrDeclarationBase(startOffset, endOffset, origin), IrTypeAlias {
     init {
         symbol.bind(this)
     }
@@ -38,13 +33,5 @@ class IrTypeAliasImpl(
     override val descriptor: TypeAliasDescriptor
         get() = symbol.descriptor
 
-    override var typeParametersField: List<IrTypeParameter> = emptyList()
-
-    override var typeParameters: List<IrTypeParameter>
-        get() = getCarrier().typeParametersField
-        set(v) {
-            if (typeParameters !== v) {
-                setCarrier().typeParametersField = v
-            }
-        }
+    override var typeParameters: List<IrTypeParameter> = emptyList()
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeParameterImpl.kt

@@ -20,7 +20,6 @@ import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.TypeParameterCarrier
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.name.Name
@@ -36,11 +35,7 @@ class IrTypeParameterImpl(
     override val index: Int,
     override val isReified: Boolean,
     override val variance: Variance
-) :
-    IrDeclarationBase<TypeParameterCarrier>(startOffset, endOffset, origin),
-    IrTypeParameter,
-    TypeParameterCarrier {
-
+) : IrDeclarationBase(startOffset, endOffset, origin), IrTypeParameter {
     init {
         symbol.bind(this)
     }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrValueParameterImpl.kt

@@ -20,7 +20,6 @@ import org.jetbrains.kotlin.descriptors.ParameterDescriptor
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrValueParameter
-import org.jetbrains.kotlin.ir.declarations.impl.carriers.ValueParameterCarrier
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.symbols.IrValueParameterSymbol
 import org.jetbrains.kotlin.ir.types.IrType
@@ -37,11 +36,7 @@ class IrValueParameterImpl(
     override val varargElementType: IrType?,
     override val isCrossinline: Boolean,
     override val isNoinline: Boolean
-) :
-    IrDeclarationBase<ValueParameterCarrier>(startOffset, endOffset, origin),
-    IrValueParameter,
-    ValueParameterCarrier {
-
+) : IrDeclarationBase(startOffset, endOffset, origin), IrValueParameter {
     @ObsoleteDescriptorBasedAPI
     override val descriptor: ParameterDescriptor
         get() = symbol.descriptor
@@ -50,16 +45,5 @@ class IrValueParameterImpl(
         symbol.bind(this)
     }
 
-    override var defaultValueField: IrExpressionBody? = null
-
-    override var defaultValue: IrExpressionBody?
-        get() = getCarrier().defaultValueField
-        set(v) {
-            if (defaultValue !== v) {
-                if (v is IrBodyBase<*>) {
-                    v.container = this
-                }
-                setCarrier().defaultValueField = v
-            }
-        }
+    override var defaultValue: IrExpressionBody? = null
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrBlockBodyImpl.kt

@@ -16,28 +16,22 @@
 
 package org.jetbrains.kotlin.ir.expressions.impl
 
+import org.jetbrains.kotlin.ir.IrElementBase
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.declarations.IrFactory
-import org.jetbrains.kotlin.ir.declarations.impl.IrBodyBase
 import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
 import org.jetbrains.kotlin.ir.expressions.IrBlockBody
 
-class IrBlockBodyImpl(
-    startOffset: Int,
-    endOffset: Int,
-    initializer: (IrBlockBody.() -> Unit)? = null
-) :
-    IrBodyBase<IrBlockBodyImpl>(startOffset, endOffset, initializer),
-    IrBlockBody {
-
+class IrBlockBodyImpl(startOffset: Int, endOffset: Int) : IrElementBase(startOffset, endOffset), IrBlockBody {
     constructor(startOffset: Int, endOffset: Int, statements: List<IrStatement>) : this(startOffset, endOffset) {
-        statementsField.addAll(statements)
+        this.statements.addAll(statements)
     }
 
-    private var statementsField: MutableList<IrStatement> = ArrayList()
+    constructor(startOffset: Int, endOffset: Int, initializer: IrBlockBody.() -> Unit) : this(startOffset, endOffset) {
+        this.initializer()
+    }
 
-    override val statements: MutableList<IrStatement>
-        get() = checkEnabled { statementsField }
+    override val statements: MutableList<IrStatement> = ArrayList()
 
     override val factory: IrFactory
         get() = IrFactoryImpl

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrExpressionBodyImpl.kt

@@ -16,33 +16,28 @@
 
 package org.jetbrains.kotlin.ir.expressions.impl
 
+import org.jetbrains.kotlin.ir.IrElementBase
 import org.jetbrains.kotlin.ir.declarations.IrFactory
-import org.jetbrains.kotlin.ir.declarations.impl.IrBodyBase
 import org.jetbrains.kotlin.ir.declarations.impl.IrFactoryImpl
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 
-class IrExpressionBodyImpl private constructor(
+class IrExpressionBodyImpl(
     startOffset: Int,
     endOffset: Int,
-    private var expressionField: IrExpression? = null,
     initializer: (IrExpressionBody.() -> Unit)? = null
-) :
-    IrBodyBase<IrExpressionBodyImpl>(startOffset, endOffset, initializer),
-    IrExpressionBody {
+) : IrElementBase(startOffset, endOffset), IrExpressionBody {
+    init {
+        initializer?.invoke(this)
+    }
 
-    constructor(expression: IrExpression) : this(expression.startOffset, expression.endOffset, expression, null)
+    constructor(startOffset: Int, endOffset: Int, expression: IrExpression) : this(startOffset, endOffset) {
+        this.expression = expression
+    }
 
-    constructor(startOffset: Int, endOffset: Int, expression: IrExpression) : this(startOffset, endOffset, expression, null)
+    constructor(expression: IrExpression) : this(expression.startOffset, expression.endOffset, expression)
 
-    constructor(startOffset: Int, endOffset: Int, initializer: IrExpressionBody.() -> Unit) :
-            this(startOffset, endOffset, null, initializer)
-
-    override var expression: IrExpression
-        get() = checkEnabled { expressionField!! }
-        set(e) {
-            checkEnabled { expressionField = e }
-        }
+    override lateinit var expression: IrExpression
 
     override val factory: IrFactory
         get() = IrFactoryImpl