From 771e7574f4edfe59e425f914bf56b65f242eea64 Mon Sep 17 00:00:00 2001
From: Alexander Udalov <alexander.udalov@jetbrains.com>
Date: Wed, 22 Jul 2020 14:09:30 +0200
Subject: [PATCH] IR: make subtypes of IrDeclaration classes

---
 .../kotlin/fir/lazy/Fir2IrLazyClass.kt        |  2 +-
 .../kotlin/fir/lazy/Fir2IrLazyConstructor.kt  |  2 +-
 .../kotlin/fir/lazy/Fir2IrLazyProperty.kt     |  2 +-
 .../fir/lazy/Fir2IrLazySimpleFunction.kt      |  2 +-
 .../impl/IrAnonymousInitializerImpl.kt        |  2 +-
 .../ir/declarations/impl/IrClassImpl.kt       |  2 +-
 .../ir/declarations/impl/IrConstructorImpl.kt |  2 +-
 .../ir/declarations/impl/IrEnumEntryImpl.kt   |  2 +-
 .../impl/IrErrorDeclarationImpl.kt            |  2 +-
 .../ir/declarations/impl/IrFieldImpl.kt       |  2 +-
 .../ir/declarations/impl/IrFunctionImpl.kt    |  2 +-
 .../impl/IrLocalDelegatedPropertyImpl.kt      |  2 +-
 .../ir/declarations/impl/IrPropertyImpl.kt    |  2 +-
 .../ir/declarations/impl/IrTypeAliasImpl.kt   |  2 +-
 .../declarations/impl/IrTypeParameterImpl.kt  |  2 +-
 .../declarations/impl/IrValueParameterImpl.kt |  2 +-
 .../PersistentIrAnonymousInitializer.kt       |  4 +--
 .../persistent/PersistentIrClass.kt           |  3 +-
 .../persistent/PersistentIrConstructor.kt     |  3 +-
 .../persistent/PersistentIrEnumEntry.kt       |  4 +--
 .../PersistentIrErrorDeclaration.kt           |  2 +-
 .../persistent/PersistentIrField.kt           |  4 +--
 .../persistent/PersistentIrFunction.kt        |  3 +-
 .../PersistentIrLocalDelegatedProperty.kt     |  2 +-
 .../persistent/PersistentIrProperty.kt        |  4 +--
 .../persistent/PersistentIrTypeAlias.kt       |  3 +-
 .../persistent/PersistentIrTypeParameter.kt   |  3 +-
 .../persistent/PersistentIrValueParameter.kt  |  3 +-
 .../ir/declarations/IrAnonymousInitializer.kt |  9 +++---
 .../kotlin/ir/declarations/IrClass.kt         | 28 +++++++++----------
 .../kotlin/ir/declarations/IrConstructor.kt   |  6 ++--
 .../kotlin/ir/declarations/IrEnumEntry.kt     |  8 +++---
 .../ir/declarations/IrErrorDeclaration.kt     |  2 +-
 .../kotlin/ir/declarations/IrField.kt         | 16 +++++------
 .../kotlin/ir/declarations/IrFunction.kt      | 22 +++++++--------
 .../declarations/IrLocalDelegatedProperty.kt  | 16 +++++------
 .../kotlin/ir/declarations/IrProperty.kt      | 26 ++++++++---------
 .../kotlin/ir/declarations/IrScript.kt        |  6 ++--
 .../ir/declarations/IrSimpleFunction.kt       | 16 +++++------
 .../kotlin/ir/declarations/IrTypeAlias.kt     |  8 +++---
 .../kotlin/ir/declarations/IrTypeParameter.kt | 12 ++++----
 .../ir/declarations/IrValueDeclaration.kt     | 10 +++----
 .../ir/declarations/IrValueParameter.kt       | 14 +++++-----
 .../kotlin/ir/declarations/IrVariable.kt      | 13 ++++-----
 .../ir/declarations/impl/IrScriptImpl.kt      |  5 ++--
 .../ir/declarations/impl/IrVariableImpl.kt    |  6 ++--
 .../ir/declarations/lazy/IrLazyClass.kt       |  2 +-
 .../ir/declarations/lazy/IrLazyConstructor.kt |  2 +-
 .../declarations/lazy/IrLazyEnumEntryImpl.kt  |  2 +-
 .../ir/declarations/lazy/IrLazyField.kt       |  2 +-
 .../ir/declarations/lazy/IrLazyFunction.kt    |  2 +-
 .../ir/declarations/lazy/IrLazyProperty.kt    |  2 +-
 .../ir/declarations/lazy/IrLazyTypeAlias.kt   |  2 +-
 .../declarations/lazy/IrLazyTypeParameter.kt  |  2 +-
 54 files changed, 152 insertions(+), 157 deletions(-)

diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyClass.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyClass.kt
index 851c8bd34c9..db3c29446a8 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyClass.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyClass.kt
@@ -31,7 +31,7 @@ class Fir2IrLazyClass(
     override var origin: IrDeclarationOrigin,
     override val fir: FirRegularClass,
     override val symbol: Fir2IrClassSymbol,
-) : IrClass, AbstractFir2IrLazyDeclaration<FirRegularClass, IrClass>, Fir2IrComponents by components {
+) : IrClass(), AbstractFir2IrLazyDeclaration<FirRegularClass, IrClass>, Fir2IrComponents by components {
     init {
         symbol.bind(this)
         classifierStorage.preCacheTypeParameters(fir)
diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyConstructor.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyConstructor.kt
index 6fd373df117..1ccabb3a3e6 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyConstructor.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyConstructor.kt
@@ -29,7 +29,7 @@ class Fir2IrLazyConstructor(
     override var origin: IrDeclarationOrigin,
     override val fir: FirConstructor,
     override val symbol: Fir2IrConstructorSymbol,
-) : IrConstructor, AbstractFir2IrLazyDeclaration<FirConstructor, IrConstructor>, Fir2IrComponents by components {
+) : IrConstructor(), AbstractFir2IrLazyDeclaration<FirConstructor, IrConstructor>, Fir2IrComponents by components {
     init {
         symbol.bind(this)
         classifierStorage.preCacheTypeParameters(fir)
diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyProperty.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyProperty.kt
index 67ea89fcea7..f737e2c83b9 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyProperty.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyProperty.kt
@@ -32,7 +32,7 @@ class Fir2IrLazyProperty(
     override val fir: FirProperty,
     override val symbol: Fir2IrPropertySymbol,
     override val isFakeOverride: Boolean
-) : IrProperty, AbstractFir2IrLazyDeclaration<FirProperty, IrProperty>, Fir2IrComponents by components {
+) : IrProperty(), AbstractFir2IrLazyDeclaration<FirProperty, IrProperty>, Fir2IrComponents by components {
     init {
         symbol.bind(this)
         classifierStorage.preCacheTypeParameters(fir)
diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazySimpleFunction.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazySimpleFunction.kt
index a499711187c..461d24b3bfa 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazySimpleFunction.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazySimpleFunction.kt
@@ -33,7 +33,7 @@ class Fir2IrLazySimpleFunction(
     firParent: FirRegularClass,
     override val symbol: Fir2IrSimpleFunctionSymbol,
     override val isFakeOverride: Boolean
-) : IrSimpleFunction, AbstractFir2IrLazyDeclaration<FirSimpleFunction, IrSimpleFunction>, Fir2IrComponents by components {
+) : IrSimpleFunction(), AbstractFir2IrLazyDeclaration<FirSimpleFunction, IrSimpleFunction>, Fir2IrComponents by components {
     init {
         symbol.bind(this)
         classifierStorage.preCacheTypeParameters(fir)
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrAnonymousInitializerImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrAnonymousInitializerImpl.kt
index 55e2aaf614a..94e340d9fc2 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrAnonymousInitializerImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrAnonymousInitializerImpl.kt
@@ -32,7 +32,7 @@ class IrAnonymousInitializerImpl(
     override var origin: IrDeclarationOrigin,
     override val symbol: IrAnonymousInitializerSymbol,
     override val isStatic: Boolean = false
-) : IrAnonymousInitializer {
+) : IrAnonymousInitializer() {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrClassImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrClassImpl.kt
index 72b65d1d20e..65ed380aab0 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrClassImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrClassImpl.kt
@@ -41,7 +41,7 @@ class IrClassImpl(
     override val isExpect: Boolean = false,
     override val isFun: Boolean = false,
     override val source: SourceElement = SourceElement.NO_SOURCE
-) : IrClass {
+) : IrClass() {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrConstructorImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrConstructorImpl.kt
index e08d7249be8..aa3f8c7a30f 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrConstructorImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrConstructorImpl.kt
@@ -38,7 +38,7 @@ class IrConstructorImpl(
     override val isExternal: Boolean,
     override val isPrimary: Boolean,
     override val isExpect: Boolean,
-) : IrConstructor {
+) : IrConstructor() {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrEnumEntryImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrEnumEntryImpl.kt
index e7f75f4eb35..76504e68280 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrEnumEntryImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrEnumEntryImpl.kt
@@ -30,7 +30,7 @@ class IrEnumEntryImpl(
     override var origin: IrDeclarationOrigin,
     override val symbol: IrEnumEntrySymbol,
     override val name: Name
-) : IrEnumEntry {
+) : IrEnumEntry() {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrErrorDeclarationImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrErrorDeclarationImpl.kt
index 30bcdc17b91..7689b17e41b 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrErrorDeclarationImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrErrorDeclarationImpl.kt
@@ -29,7 +29,7 @@ class IrErrorDeclarationImpl(
     override val startOffset: Int,
     override val endOffset: Int,
     override val descriptor: DeclarationDescriptor
-) : IrErrorDeclaration {
+) : IrErrorDeclaration() {
     override var origin: IrDeclarationOrigin = IrDeclarationOrigin.DEFINED
 
     override val factory: IrFactory
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrFieldImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrFieldImpl.kt
index 5f77315d4bf..f5f947a2b28 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrFieldImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrFieldImpl.kt
@@ -38,7 +38,7 @@ class IrFieldImpl(
     override val isFinal: Boolean,
     override val isExternal: Boolean,
     override val isStatic: Boolean,
-) : IrField {
+) : IrField() {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrFunctionImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrFunctionImpl.kt
index 6ff452a2fe0..f06148db751 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrFunctionImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrFunctionImpl.kt
@@ -32,7 +32,7 @@ abstract class IrFunctionCommonImpl(
     override val isOperator: Boolean,
     override val isInfix: Boolean,
     override val isExpect: Boolean,
-) : IrSimpleFunction {
+) : IrSimpleFunction() {
     override val factory: IrFactory
         get() = IrFactoryImpl
 
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrLocalDelegatedPropertyImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrLocalDelegatedPropertyImpl.kt
index 239f6ed3634..6fd07670734 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrLocalDelegatedPropertyImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrLocalDelegatedPropertyImpl.kt
@@ -32,7 +32,7 @@ class IrLocalDelegatedPropertyImpl(
     override val name: Name,
     override val type: IrType,
     override val isVar: Boolean
-) : IrLocalDelegatedProperty {
+) : IrLocalDelegatedProperty() {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrPropertyImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrPropertyImpl.kt
index 1e9105b215a..2ad8044a6ed 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrPropertyImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrPropertyImpl.kt
@@ -38,7 +38,7 @@ abstract class IrPropertyCommonImpl(
     override val isDelegated: Boolean,
     override val isExternal: Boolean,
     override val isExpect: Boolean,
-) : IrProperty {
+) : IrProperty() {
     override val factory: IrFactory
         get() = IrFactoryImpl
 
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeAliasImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeAliasImpl.kt
index 634cb65a010..4bb40cd6f32 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeAliasImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeAliasImpl.kt
@@ -23,7 +23,7 @@ class IrTypeAliasImpl(
     override val expandedType: IrType,
     override val isActual: Boolean,
     override var origin: IrDeclarationOrigin
-) : IrTypeAlias {
+) : IrTypeAlias() {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeParameterImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeParameterImpl.kt
index 48ccbecc4bb..c18c62ea380 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeParameterImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeParameterImpl.kt
@@ -38,7 +38,7 @@ class IrTypeParameterImpl(
     override val index: Int,
     override val isReified: Boolean,
     override val variance: Variance
-) : IrTypeParameter {
+) : IrTypeParameter() {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrValueParameterImpl.kt b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrValueParameterImpl.kt
index e943371b993..493ea69a2b9 100644
--- a/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrValueParameterImpl.kt
+++ b/compiler/ir/ir.tree.impl/src/org/jetbrains/kotlin/ir/declarations/impl/IrValueParameterImpl.kt
@@ -39,7 +39,7 @@ class IrValueParameterImpl(
     override val varargElementType: IrType?,
     override val isCrossinline: Boolean,
     override val isNoinline: Boolean
-) : IrValueParameter {
+) : IrValueParameter() {
     @ObsoleteDescriptorBasedAPI
     override val descriptor: ParameterDescriptor
         get() = symbol.descriptor
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrAnonymousInitializer.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrAnonymousInitializer.kt
index f5bfd4a1337..e724238189f 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrAnonymousInitializer.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrAnonymousInitializer.kt
@@ -34,8 +34,8 @@ internal class PersistentIrAnonymousInitializer(
     origin: IrDeclarationOrigin,
     override val symbol: IrAnonymousInitializerSymbol,
     override val isStatic: Boolean = false
-) : PersistentIrDeclarationBase<AnonymousInitializerCarrier>,
-    IrAnonymousInitializer,
+) : IrAnonymousInitializer(),
+    PersistentIrDeclarationBase<AnonymousInitializerCarrier>,
     AnonymousInitializerCarrier {
 
     init {
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrClass.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrClass.kt
index ec6a3bf2b96..5ccd9acd8bb 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrClass.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrClass.kt
@@ -44,9 +44,8 @@ internal class PersistentIrClass(
     override val isExpect: Boolean = false,
     override val isFun: Boolean = false,
     override val source: SourceElement = SourceElement.NO_SOURCE
-) :
+) : IrClass(),
     PersistentIrDeclarationBase<ClassCarrier>,
-    IrClass,
     ClassCarrier {
 
     init {
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrConstructor.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrConstructor.kt
index 081293efaac..b17c289ced8 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrConstructor.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrConstructor.kt
@@ -40,9 +40,8 @@ internal class PersistentIrConstructor(
     override val isExternal: Boolean,
     override val isPrimary: Boolean,
     override val isExpect: Boolean
-) :
+) : IrConstructor(),
     PersistentIrDeclarationBase<ConstructorCarrier>,
-    IrConstructor,
     ConstructorCarrier {
 
     init {
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrEnumEntry.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrEnumEntry.kt
index 1f08d48e294..33243e7d488 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrEnumEntry.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrEnumEntry.kt
@@ -32,8 +32,8 @@ internal class PersistentIrEnumEntry(
     origin: IrDeclarationOrigin,
     override val symbol: IrEnumEntrySymbol,
     override val name: Name
-) : PersistentIrDeclarationBase<EnumEntryCarrier>,
-    IrEnumEntry,
+) : IrEnumEntry(),
+    PersistentIrDeclarationBase<EnumEntryCarrier>,
     EnumEntryCarrier {
 
     init {
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrErrorDeclaration.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrErrorDeclaration.kt
index b92329e3102..2864d65eb5c 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrErrorDeclaration.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrErrorDeclaration.kt
@@ -31,7 +31,7 @@ internal class PersistentIrErrorDeclaration(
     override val startOffset: Int,
     override val endOffset: Int,
     override val descriptor: DeclarationDescriptor
-) : PersistentIrDeclarationBase<ErrorCarrier>, IrErrorDeclaration, ErrorCarrier {
+) : PersistentIrDeclarationBase<ErrorCarrier>, IrErrorDeclaration(), ErrorCarrier {
     override var lastModified: Int = stageController.currentStage
     override var loweredUpTo: Int = stageController.currentStage
     override var values: Array<Carrier>? = null
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrField.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrField.kt
index 9d986be3326..a8e3b9a830d 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrField.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrField.kt
@@ -40,8 +40,8 @@ internal class PersistentIrField(
     override val isFinal: Boolean,
     override val isExternal: Boolean,
     override val isStatic: Boolean
-) : PersistentIrDeclarationBase<FieldCarrier>,
-    IrField,
+) : IrField(),
+    PersistentIrDeclarationBase<FieldCarrier>,
     FieldCarrier {
 
     init {
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrFunction.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrFunction.kt
index 961fbc92a6a..5ecba9a58e6 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrFunction.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrFunction.kt
@@ -34,9 +34,8 @@ internal abstract class PersistentIrFunctionCommon(
     override val isOperator: Boolean,
     override val isInfix: Boolean,
     override val isExpect: Boolean,
-) :
+) : IrSimpleFunction(),
     PersistentIrDeclarationBase<FunctionCarrier>,
-    IrSimpleFunction,
     FunctionCarrier {
 
     override var lastModified: Int = stageController.currentStage
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrLocalDelegatedProperty.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrLocalDelegatedProperty.kt
index 57663bf5681..3d0e54132eb 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrLocalDelegatedProperty.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrLocalDelegatedProperty.kt
@@ -37,7 +37,7 @@ internal class PersistentIrLocalDelegatedProperty(
     override val isVar: Boolean
 ) :
     PersistentIrDeclarationBase<LocalDelegatedPropertyCarrier>,
-    IrLocalDelegatedProperty,
+    IrLocalDelegatedProperty(),
     LocalDelegatedPropertyCarrier {
 
     init {
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrProperty.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrProperty.kt
index b67b5d267bb..8ba511968b1 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrProperty.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrProperty.kt
@@ -40,8 +40,8 @@ internal abstract class PersistentIrPropertyCommon(
     override val isDelegated: Boolean,
     override val isExternal: Boolean,
     override val isExpect: Boolean,
-) : PersistentIrDeclarationBase<PropertyCarrier>,
-    IrProperty,
+) : IrProperty(),
+    PersistentIrDeclarationBase<PropertyCarrier>,
     PropertyCarrier {
 
     override var lastModified: Int = stageController.currentStage
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrTypeAlias.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrTypeAlias.kt
index bdbbdd11c2c..c1db7726e36 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrTypeAlias.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrTypeAlias.kt
@@ -25,9 +25,8 @@ internal class PersistentIrTypeAlias(
     override val expandedType: IrType,
     override val isActual: Boolean,
     origin: IrDeclarationOrigin
-) :
+) : IrTypeAlias(),
     PersistentIrDeclarationBase<TypeAliasCarrier>,
-    IrTypeAlias,
     TypeAliasCarrier {
 
     init {
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrTypeParameter.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrTypeParameter.kt
index d6bf4d1c1ee..c0133964d8f 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrTypeParameter.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrTypeParameter.kt
@@ -40,9 +40,8 @@ internal class PersistentIrTypeParameter(
     override val index: Int,
     override val isReified: Boolean,
     override val variance: Variance
-) :
+) : IrTypeParameter(),
     PersistentIrDeclarationBase<TypeParameterCarrier>,
-    IrTypeParameter,
     TypeParameterCarrier {
 
     init {
diff --git a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrValueParameter.kt b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrValueParameter.kt
index 1e5aa4b2496..7746e667b33 100644
--- a/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrValueParameter.kt
+++ b/compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrValueParameter.kt
@@ -41,9 +41,8 @@ internal class PersistentIrValueParameter(
     override val varargElementType: IrType?,
     override val isCrossinline: Boolean,
     override val isNoinline: Boolean
-) :
+) : IrValueParameter(),
     PersistentIrDeclarationBase<ValueParameterCarrier>,
-    IrValueParameter,
     ValueParameterCarrier {
 
     @ObsoleteDescriptorBasedAPI
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrAnonymousInitializer.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrAnonymousInitializer.kt
index 0a89f274e22..f60cd81f169 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrAnonymousInitializer.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrAnonymousInitializer.kt
@@ -23,12 +23,13 @@ import org.jetbrains.kotlin.ir.symbols.IrAnonymousInitializerSymbol
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrAnonymousInitializer : IrSymbolDeclaration<IrAnonymousInitializerSymbol> {
+abstract class IrAnonymousInitializer : IrSymbolDeclaration<IrAnonymousInitializerSymbol> {
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: ClassDescriptor // TODO special descriptor for anonymous initializer blocks
-    val isStatic: Boolean
+    abstract override val descriptor: ClassDescriptor // TODO special descriptor for anonymous initializer blocks
 
-    var body: IrBlockBody
+    abstract val isStatic: Boolean
+
+    abstract var body: IrBlockBody
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitAnonymousInitializer(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrClass.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrClass.kt
index d8b02d4d78b..b9eb2f04b6e 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrClass.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrClass.kt
@@ -28,28 +28,28 @@ import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrClass :
+abstract class IrClass :
     IrSymbolDeclaration<IrClassSymbol>, IrDeclarationWithName, IrDeclarationWithVisibility,
     IrDeclarationContainer, IrTypeParametersContainer, IrAttributeContainer, IrMetadataSourceOwner {
 
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: ClassDescriptor
+    abstract override val descriptor: ClassDescriptor
 
-    val kind: ClassKind
-    var modality: Modality
-    val isCompanion: Boolean
-    val isInner: Boolean
-    val isData: Boolean
-    val isExternal: Boolean
-    val isInline: Boolean
-    val isExpect: Boolean
-    val isFun: Boolean
+    abstract val kind: ClassKind
+    abstract var modality: Modality
+    abstract val isCompanion: Boolean
+    abstract val isInner: Boolean
+    abstract val isData: Boolean
+    abstract val isExternal: Boolean
+    abstract val isInline: Boolean
+    abstract val isExpect: Boolean
+    abstract val isFun: Boolean
 
-    val source: SourceElement
+    abstract val source: SourceElement
 
-    var superTypes: List<IrType>
+    abstract var superTypes: List<IrType>
 
-    var thisReceiver: IrValueParameter?
+    abstract var thisReceiver: IrValueParameter?
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitClass(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrConstructor.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrConstructor.kt
index b16c0d2325a..0d07f928444 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrConstructor.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrConstructor.kt
@@ -21,11 +21,11 @@ import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrConstructor : IrFunction, IrSymbolDeclaration<IrConstructorSymbol> {
+abstract class IrConstructor : IrFunction(), IrSymbolDeclaration<IrConstructorSymbol> {
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: ClassConstructorDescriptor
+    abstract override val descriptor: ClassConstructorDescriptor
 
-    val isPrimary: Boolean
+    abstract val isPrimary: Boolean
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitConstructor(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrEnumEntry.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrEnumEntry.kt
index 1f6194d85fe..3cd35d51a6f 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrEnumEntry.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrEnumEntry.kt
@@ -23,12 +23,12 @@ import org.jetbrains.kotlin.ir.symbols.IrEnumEntrySymbol
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrEnumEntry : IrSymbolDeclaration<IrEnumEntrySymbol>, IrDeclarationWithName {
+abstract class IrEnumEntry : IrSymbolDeclaration<IrEnumEntrySymbol>, IrDeclarationWithName {
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: ClassDescriptor
+    abstract override val descriptor: ClassDescriptor
 
-    var correspondingClass: IrClass?
-    var initializerExpression: IrExpressionBody?
+    abstract var correspondingClass: IrClass?
+    abstract var initializerExpression: IrExpressionBody?
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitEnumEntry(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrErrorDeclaration.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrErrorDeclaration.kt
index 24fac560699..e8966ea1ba6 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrErrorDeclaration.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrErrorDeclaration.kt
@@ -19,7 +19,7 @@ package org.jetbrains.kotlin.ir.declarations
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrErrorDeclaration : IrDeclaration {
+abstract class IrErrorDeclaration : IrDeclaration {
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitErrorDeclaration(this, data)
 
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrField.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrField.kt
index d70f4578c14..4a762b44c6d 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrField.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrField.kt
@@ -14,21 +14,21 @@ import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrField :
+abstract class IrField :
     IrSymbolDeclaration<IrFieldSymbol>,
     IrDeclarationWithName, IrDeclarationWithVisibility, IrDeclarationParent, IrMetadataSourceOwner {
 
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: PropertyDescriptor
+    abstract override val descriptor: PropertyDescriptor
 
-    val type: IrType
-    val isFinal: Boolean
-    val isExternal: Boolean
-    val isStatic: Boolean
+    abstract val type: IrType
+    abstract val isFinal: Boolean
+    abstract val isExternal: Boolean
+    abstract val isStatic: Boolean
 
-    var initializer: IrExpressionBody?
+    abstract var initializer: IrExpressionBody?
 
-    var correspondingPropertySymbol: IrPropertySymbol?
+    abstract var correspondingPropertySymbol: IrPropertySymbol?
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitField(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrFunction.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrFunction.kt
index 655d5281193..6b011116ca3 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrFunction.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrFunction.kt
@@ -27,25 +27,25 @@ import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrFunction :
+abstract class IrFunction :
     IrDeclarationWithName, IrDeclarationWithVisibility, IrTypeParametersContainer, IrSymbolOwner, IrDeclarationParent, IrReturnTarget,
     IrMetadataSourceOwner {
 
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: FunctionDescriptor
-    override val symbol: IrFunctionSymbol
+    abstract override val descriptor: FunctionDescriptor
+    abstract override val symbol: IrFunctionSymbol
 
-    val isInline: Boolean // NB: there's an inline constructor for Array and each primitive array class
-    val isExternal: Boolean
-    val isExpect: Boolean
+    abstract val isInline: Boolean // NB: there's an inline constructor for Array and each primitive array class
+    abstract val isExternal: Boolean
+    abstract val isExpect: Boolean
 
-    var returnType: IrType
+    abstract var returnType: IrType
 
-    var dispatchReceiverParameter: IrValueParameter?
-    var extensionReceiverParameter: IrValueParameter?
-    var valueParameters: List<IrValueParameter>
+    abstract var dispatchReceiverParameter: IrValueParameter?
+    abstract var extensionReceiverParameter: IrValueParameter?
+    abstract var valueParameters: List<IrValueParameter>
 
-    var body: IrBody?
+    abstract var body: IrBody?
 
     override fun <D> acceptChildren(visitor: IrElementVisitor<Unit, D>, data: D) {
         typeParameters.forEach { it.accept(visitor, data) }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrLocalDelegatedProperty.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrLocalDelegatedProperty.kt
index cf769469f78..a2cf1b3e78d 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrLocalDelegatedProperty.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrLocalDelegatedProperty.kt
@@ -23,21 +23,21 @@ import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrLocalDelegatedProperty :
+abstract class IrLocalDelegatedProperty :
     IrDeclarationWithName,
     IrSymbolOwner,
     IrMetadataSourceOwner {
 
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: VariableDescriptorWithAccessors
-    override val symbol: IrLocalDelegatedPropertySymbol
+    abstract override val descriptor: VariableDescriptorWithAccessors
+    abstract override val symbol: IrLocalDelegatedPropertySymbol
 
-    val type: IrType
-    val isVar: Boolean
+    abstract val type: IrType
+    abstract val isVar: Boolean
 
-    var delegate: IrVariable
-    var getter: IrFunction
-    var setter: IrFunction?
+    abstract var delegate: IrVariable
+    abstract var getter: IrFunction
+    abstract var setter: IrFunction?
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitLocalDelegatedProperty(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrProperty.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrProperty.kt
index 5ed24f31a4c..6689ea0ec59 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrProperty.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrProperty.kt
@@ -22,22 +22,22 @@ import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrProperty : IrOverridableMember, IrMetadataSourceOwner {
+abstract class IrProperty : IrOverridableMember, IrMetadataSourceOwner {
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: PropertyDescriptor
-    override val symbol: IrPropertySymbol
+    abstract override val descriptor: PropertyDescriptor
+    abstract override val symbol: IrPropertySymbol
 
-    val isVar: Boolean
-    val isConst: Boolean
-    val isLateinit: Boolean
-    val isDelegated: Boolean
-    val isExternal: Boolean
-    val isExpect: Boolean
-    val isFakeOverride: Boolean
+    abstract val isVar: Boolean
+    abstract val isConst: Boolean
+    abstract val isLateinit: Boolean
+    abstract val isDelegated: Boolean
+    abstract val isExternal: Boolean
+    abstract val isExpect: Boolean
+    abstract val isFakeOverride: Boolean
 
-    var backingField: IrField?
-    var getter: IrSimpleFunction?
-    var setter: IrSimpleFunction?
+    abstract var backingField: IrField?
+    abstract var getter: IrSimpleFunction?
+    abstract var setter: IrSimpleFunction?
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitProperty(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrScript.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrScript.kt
index f24b333c717..6591891490e 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrScript.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrScript.kt
@@ -10,9 +10,9 @@ import org.jetbrains.kotlin.ir.symbols.IrScriptSymbol
 
 //TODO: make IrScript as IrPackageFragment, because script is used as a file, not as a class
 //NOTE: declarations and statements stored separately
-interface IrScript : IrSymbolDeclaration<IrScriptSymbol>, IrDeclarationContainer, IrDeclarationWithName, IrDeclarationParent {
-    val statements: MutableList<IrStatement>
+abstract class IrScript : IrSymbolDeclaration<IrScriptSymbol>, IrDeclarationContainer, IrDeclarationWithName, IrDeclarationParent {
+    abstract val statements: MutableList<IrStatement>
 
     // NOTE: is the result of the FE conversion, because there script interpreted as a class and has receiver
-    var thisReceiver: IrValueParameter
+    abstract var thisReceiver: IrValueParameter
 }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrSimpleFunction.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrSimpleFunction.kt
index f0dd6a7aaf2..6a41b6e6eec 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrSimpleFunction.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrSimpleFunction.kt
@@ -9,20 +9,20 @@ import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrSimpleFunction :
-    IrFunction,
+abstract class IrSimpleFunction :
+    IrFunction(),
     IrSymbolDeclaration<IrSimpleFunctionSymbol>,
     IrOverridableDeclaration<IrSimpleFunctionSymbol>,
     IrOverridableMember,
     IrAttributeContainer {
 
-    val isTailrec: Boolean
-    val isSuspend: Boolean
-    val isFakeOverride: Boolean
-    val isOperator: Boolean
-    val isInfix: Boolean
+    abstract val isTailrec: Boolean
+    abstract val isSuspend: Boolean
+    abstract val isFakeOverride: Boolean
+    abstract val isOperator: Boolean
+    abstract val isInfix: Boolean
 
-    var correspondingPropertySymbol: IrPropertySymbol?
+    abstract var correspondingPropertySymbol: IrPropertySymbol?
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitSimpleFunction(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeAlias.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeAlias.kt
index 3c13b32ec27..392575f0687 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeAlias.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeAlias.kt
@@ -13,17 +13,17 @@ import org.jetbrains.kotlin.ir.util.transformIfNeeded
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrTypeAlias :
+abstract class IrTypeAlias :
     IrSymbolDeclaration<IrTypeAliasSymbol>,
     IrDeclarationWithName,
     IrDeclarationWithVisibility,
     IrTypeParametersContainer {
 
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: TypeAliasDescriptor
+    abstract override val descriptor: TypeAliasDescriptor
 
-    val isActual: Boolean
-    val expandedType: IrType
+    abstract val isActual: Boolean
+    abstract val expandedType: IrType
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitTypeAlias(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeParameter.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeParameter.kt
index 961a13e8c9f..1c610665866 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeParameter.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeParameter.kt
@@ -24,14 +24,14 @@ import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.types.Variance
 
-interface IrTypeParameter : IrSymbolDeclaration<IrTypeParameterSymbol>, IrDeclarationWithName {
+abstract class IrTypeParameter : IrSymbolDeclaration<IrTypeParameterSymbol>, IrDeclarationWithName {
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: TypeParameterDescriptor
+    abstract override val descriptor: TypeParameterDescriptor
 
-    val variance: Variance
-    val index: Int
-    val isReified: Boolean
-    val superTypes: MutableList<IrType>
+    abstract val variance: Variance
+    abstract val index: Int
+    abstract val isReified: Boolean
+    abstract val superTypes: MutableList<IrType>
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitTypeParameter(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueDeclaration.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueDeclaration.kt
index 60c710fbd6e..1b235c48e25 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueDeclaration.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueDeclaration.kt
@@ -10,10 +10,10 @@ import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.symbols.IrValueSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 
-interface IrValueDeclaration : IrDeclarationWithName, IrSymbolOwner {
+abstract class IrValueDeclaration : IrDeclarationWithName, IrSymbolOwner {
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: ValueDescriptor
+    abstract override val descriptor: ValueDescriptor
 
-    override val symbol: IrValueSymbol
-    val type: IrType
-}
\ No newline at end of file
+    abstract override val symbol: IrValueSymbol
+    abstract val type: IrType
+}
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueParameter.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueParameter.kt
index 4d65eef6ccc..8e62f0db2cc 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueParameter.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueParameter.kt
@@ -24,16 +24,16 @@ import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
-interface IrValueParameter : IrValueDeclaration, IrSymbolDeclaration<IrValueParameterSymbol> {
+abstract class IrValueParameter : IrValueDeclaration(), IrSymbolDeclaration<IrValueParameterSymbol> {
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: ParameterDescriptor
+    abstract override val descriptor: ParameterDescriptor
 
-    val index: Int
-    val varargElementType: IrType?
-    val isCrossinline: Boolean
-    val isNoinline: Boolean
+    abstract val index: Int
+    abstract val varargElementType: IrType?
+    abstract val isCrossinline: Boolean
+    abstract val isNoinline: Boolean
 
-    var defaultValue: IrExpressionBody?
+    abstract var defaultValue: IrExpressionBody?
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =
         visitor.visitValueParameter(this, data)
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrVariable.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrVariable.kt
index 60a0485fe98..62bf477a1cb 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrVariable.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrVariable.kt
@@ -21,14 +21,13 @@ import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.symbols.IrVariableSymbol
 
-interface IrVariable : IrValueDeclaration, IrSymbolDeclaration<IrVariableSymbol> {
+abstract class IrVariable : IrValueDeclaration(), IrSymbolDeclaration<IrVariableSymbol> {
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: VariableDescriptor
+    abstract override val descriptor: VariableDescriptor
 
-    val isVar: Boolean
-    val isConst: Boolean
-    val isLateinit: Boolean
+    abstract val isVar: Boolean
+    abstract val isConst: Boolean
+    abstract val isLateinit: Boolean
 
-    var initializer: IrExpression?
+    abstract var initializer: IrExpression?
 }
-
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrScriptImpl.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrScriptImpl.kt
index 93856c20ca2..dbd35327cbb 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrScriptImpl.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrScriptImpl.kt
@@ -23,7 +23,7 @@ private val SCRIPT_ORIGIN = object : IrDeclarationOriginImpl("FIELD_FOR_OBJECT_I
 class IrScriptImpl(
     override val symbol: IrScriptSymbol,
     override val name: Name
-) : IrScript, IrDeclaration {
+) : IrScript() {
     override val startOffset: Int get() = UNDEFINED_OFFSET
     override val endOffset: Int get() = UNDEFINED_OFFSET
     override var origin: IrDeclarationOrigin = SCRIPT_ORIGIN
@@ -44,7 +44,8 @@ class IrScriptImpl(
     override lateinit var thisReceiver: IrValueParameter
 
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: ScriptDescriptor = symbol.descriptor
+    override val descriptor: ScriptDescriptor
+        get() = symbol.descriptor
 
     override val factory: IrFactory
         get() = error("Create IrScriptImpl directly")
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrVariableImpl.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrVariableImpl.kt
index c9b7032c08b..fbd5b9bf612 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrVariableImpl.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrVariableImpl.kt
@@ -40,8 +40,7 @@ class IrVariableImpl(
     override val isVar: Boolean,
     override val isConst: Boolean,
     override val isLateinit: Boolean
-) : IrVariable {
-
+) : IrVariable() {
     private var _parent: IrDeclarationParent? = null
     override var parent: IrDeclarationParent
         get() = _parent
@@ -57,7 +56,8 @@ class IrVariableImpl(
     }
 
     @ObsoleteDescriptorBasedAPI
-    override val descriptor: VariableDescriptor get() = symbol.descriptor
+    override val descriptor: VariableDescriptor
+        get() = symbol.descriptor
 
     override var initializer: IrExpression? = null
 
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyClass.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyClass.kt
index 643e6738a5e..4bd8816c06d 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyClass.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyClass.kt
@@ -38,7 +38,7 @@ class IrLazyClass(
     override val isFun: Boolean,
     override val stubGenerator: DeclarationStubGenerator,
     override val typeTranslator: TypeTranslator
-) : IrClass, IrLazyDeclarationBase {
+) : IrClass(), IrLazyDeclarationBase {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyConstructor.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyConstructor.kt
index 47b4eb32566..54455a95e9f 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyConstructor.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyConstructor.kt
@@ -33,7 +33,7 @@ class IrLazyConstructor(
     override val isExpect: Boolean,
     override val stubGenerator: DeclarationStubGenerator,
     override val typeTranslator: TypeTranslator,
-) : IrConstructor, IrLazyFunctionBase {
+) : IrConstructor(), IrLazyFunctionBase {
     override var parent: IrDeclarationParent by createLazyParent()
 
     override var annotations: List<IrConstructorCall> by createLazyAnnotations()
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyEnumEntryImpl.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyEnumEntryImpl.kt
index 737220d1b70..f4ade5f7e92 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyEnumEntryImpl.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyEnumEntryImpl.kt
@@ -38,7 +38,7 @@ class IrLazyEnumEntryImpl(
     override val descriptor: ClassDescriptor,
     override val stubGenerator: DeclarationStubGenerator,
     override val typeTranslator: TypeTranslator,
-) : IrEnumEntry, IrLazyDeclarationBase {
+) : IrEnumEntry(), IrLazyDeclarationBase {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyField.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyField.kt
index e514c20091f..081b1124f37 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyField.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyField.kt
@@ -36,7 +36,7 @@ class IrLazyField(
     override val isStatic: Boolean,
     override val stubGenerator: DeclarationStubGenerator,
     override val typeTranslator: TypeTranslator,
-) : IrField, IrLazyDeclarationBase {
+) : IrField(), IrLazyDeclarationBase {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyFunction.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyFunction.kt
index c4189981605..7707312d5d6 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyFunction.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyFunction.kt
@@ -41,7 +41,7 @@ class IrLazyFunction(
     override val isInfix: Boolean,
     override val stubGenerator: DeclarationStubGenerator,
     override val typeTranslator: TypeTranslator,
-) : IrSimpleFunction, IrLazyFunctionBase {
+) : IrSimpleFunction(), IrLazyFunctionBase {
     override var parent: IrDeclarationParent by createLazyParent()
 
     override var annotations: List<IrConstructorCall> by createLazyAnnotations()
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyProperty.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyProperty.kt
index 04a08bbe892..fbe6ac071c3 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyProperty.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyProperty.kt
@@ -38,7 +38,7 @@ class IrLazyProperty(
     override val stubGenerator: DeclarationStubGenerator,
     override val typeTranslator: TypeTranslator,
     bindingContext: BindingContext? = null
-) : IrProperty, IrLazyDeclarationBase {
+) : IrProperty(), IrLazyDeclarationBase {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeAlias.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeAlias.kt
index 4d9c4914ef3..bbc52c195b0 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeAlias.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeAlias.kt
@@ -28,7 +28,7 @@ class IrLazyTypeAlias(
     override val isActual: Boolean,
     override val stubGenerator: DeclarationStubGenerator,
     override val typeTranslator: TypeTranslator,
-) : IrTypeAlias, IrLazyDeclarationBase {
+) : IrTypeAlias(), IrLazyDeclarationBase {
     init {
         symbol.bind(this)
     }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeParameter.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeParameter.kt
index 07cd343cff6..6a5714ba207 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeParameter.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeParameter.kt
@@ -29,7 +29,7 @@ class IrLazyTypeParameter(
     override val variance: Variance,
     override val stubGenerator: DeclarationStubGenerator,
     override val typeTranslator: TypeTranslator,
-) : IrTypeParameter, IrLazyDeclarationBase {
+) : IrTypeParameter(), IrLazyDeclarationBase {
     init {
         symbol.bind(this)
     }