From dd8bed8b466ac064984565259d817f96301471c4 Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <Mikhail.Glukhikh@jetbrains.com>
Date: Thu, 14 Sep 2017 20:39:29 +0300
Subject: [PATCH] Migration: expect/actual in diagnostic tests

---
 .../enum/additionalEntriesInImpl.kt           |  8 +--
 .../enum/additionalEntriesInImpl.txt          | 18 +++---
 .../enum/constructorInHeaderEnum.kt           |  4 +-
 .../enum/constructorInHeaderEnum.txt          | 10 ++--
 .../multiplatform/enum/differentEntryOrder.kt |  8 +--
 .../enum/differentEntryOrder.txt              | 18 +++---
 .../multiplatform/enum/enumEntryWithBody.kt   |  2 +-
 .../multiplatform/enum/enumEntryWithBody.txt  |  8 +--
 .../tests/multiplatform/enum/simpleEnum.kt    |  4 +-
 .../tests/multiplatform/enum/simpleEnum.txt   | 10 ++--
 .../generic/membersInGenericClass.kt          | 10 ++--
 .../generic/membersInGenericClass.txt         | 16 +++---
 .../multiplatform/headerClass/classKinds.kt   | 20 +++----
 .../multiplatform/headerClass/classKinds.txt  | 26 ++++-----
 .../explicitConstructorDelegation.kt          |  4 +-
 .../explicitConstructorDelegation.txt         |  4 +-
 .../headerClass/extraHeaderOnMembers.kt       |  8 +--
 .../headerClass/extraHeaderOnMembers.txt      |  8 +--
 .../headerClass/genericClassImplTypeAlias.kt  | 40 ++++++-------
 .../headerClass/genericClassImplTypeAlias.txt | 20 +++----
 .../headerClass/headerClassMember.kt          | 14 ++---
 .../headerClass/headerClassMember.txt         | 18 +++---
 .../headerClassWithFunctionBody.kt            |  2 +-
 .../headerClassWithFunctionBody.txt           | 12 ++--
 .../headerClass/implDataClass.kt              | 12 ++--
 .../headerClass/implDataClass.txt             | 32 +++++------
 .../headerClass/implOpenClass.kt              |  8 +--
 .../headerClass/implOpenClass.txt             |  8 +--
 .../headerClass/nestedClasses.kt              | 34 +++++------
 .../headerClass/nestedClasses.txt             | 56 +++++++++----------
 .../headerClass/nestedClassesWithErrors.kt    | 36 ++++++------
 .../headerClass/nestedClassesWithErrors.txt   | 44 +++++++--------
 .../headerClass/noImplKeywordOnMember.kt      |  4 +-
 .../headerClass/noImplKeywordOnMember.txt     |  6 +-
 .../headerClass/simpleHeaderClass.kt          |  6 +-
 .../headerClass/simpleHeaderClass.txt         |  6 +-
 .../multiplatform/headerClass/superClass.kt   |  6 +-
 .../multiplatform/headerClass/superClass.txt  |  6 +-
 .../headerFunInNonHeaderClass.kt              |  2 +-
 .../multiplatform/implDelegatedMember.kt      |  4 +-
 .../multiplatform/implDelegatedMember.txt     |  6 +-
 .../tests/multiplatform/implDynamic.kt        | 12 ++--
 .../tests/multiplatform/implDynamic.txt       | 16 +++---
 .../tests/multiplatform/implFakeOverride.kt   |  4 +-
 .../tests/multiplatform/implFakeOverride.txt  |  6 +-
 .../tests/multiplatform/java/flexibleTypes.kt |  4 +-
 .../multiplatform/java/flexibleTypes.txt      |  8 +--
 .../multiplatform/java/parameterNames.kt      |  4 +-
 .../multiplatform/java/parameterNames.txt     |  4 +-
 .../multiplatform/modifierApplicability.kt    | 30 +++++-----
 .../multiplatform/modifierApplicability.txt   |  4 +-
 .../tests/multiplatform/namedArguments.kt     | 12 ++--
 .../tests/multiplatform/namedArguments.txt    | 12 ++--
 .../topLevelFun/callHeaderFun.kt              |  6 +-
 .../topLevelFun/callHeaderFun.txt             |  6 +-
 .../conflictingHeaderDeclarations.kt          |  6 +-
 .../conflictingHeaderDeclarations.txt         |  6 +-
 .../conflictingImplDeclarations.kt            | 10 ++--
 .../conflictingImplDeclarations.txt           | 10 ++--
 .../topLevelFun/defaultArguments.kt           |  2 +-
 .../topLevelFun/defaultArguments.txt          |  2 +-
 .../topLevelFun/functionModifiers.kt          | 20 +++----
 .../topLevelFun/functionModifiers.txt         | 20 +++----
 .../headerAndImplInDIfferentPackages.kt       |  6 +-
 .../headerAndImplInDIfferentPackages.txt      |  6 +-
 .../topLevelFun/headerDeclarationWithBody.kt  |  6 +-
 .../topLevelFun/headerDeclarationWithBody.txt |  6 +-
 .../topLevelFun/headerWithoutImpl.kt          |  2 +-
 .../topLevelFun/headerWithoutImpl.txt         |  2 +-
 .../topLevelFun/implDeclarationWithoutBody.kt |  6 +-
 .../implDeclarationWithoutBody.txt            |  6 +-
 .../topLevelFun/implWithoutHeader.kt          |  2 +-
 .../topLevelFun/implWithoutHeader.txt         |  2 +-
 .../multiplatform/topLevelFun/inlineFun.kt    | 12 ++--
 .../multiplatform/topLevelFun/inlineFun.txt   | 12 ++--
 .../topLevelFun/simpleHeaderFun.kt            |  6 +-
 .../topLevelFun/simpleHeaderFun.txt           |  6 +-
 .../topLevelFun/valueParameterModifiers.kt    | 32 +++++------
 .../topLevelFun/valueParameterModifiers.txt   | 32 +++++------
 .../differentKindsOfProperties.kt             | 34 +++++------
 .../differentKindsOfProperties.txt            | 28 +++++-----
 .../topLevelProperty/simpleHeaderVar.kt       |  6 +-
 .../topLevelProperty/simpleHeaderVar.txt      |  6 +-
 .../noMultiplatformProjects.kt                | 12 ++--
 .../noMultiplatformProjects.txt               |  6 +-
 85 files changed, 504 insertions(+), 504 deletions(-)

diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/additionalEntriesInImpl.kt b/compiler/testData/diagnostics/tests/multiplatform/enum/additionalEntriesInImpl.kt
index bcea2b2ac02..0fdbc9c2816 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/additionalEntriesInImpl.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/additionalEntriesInImpl.kt
@@ -1,10 +1,10 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header enum class Foo { A, B }
-header enum class Bar { X, Y, Z }
+expect enum class Foo { A, B }
+expect enum class Bar { X, Y, Z }
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-impl enum class Foo { A, B, C, D, E }
-impl enum class Bar { V, X, W, Y, Z }
+actual enum class Foo { A, B, C, D, E }
+actual enum class Bar { V, X, W, Y, Z }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/additionalEntriesInImpl.txt b/compiler/testData/diagnostics/tests/multiplatform/enum/additionalEntriesInImpl.txt
index 0a9600148d1..4cd9ac28660 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/additionalEntriesInImpl.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/additionalEntriesInImpl.txt
@@ -1,12 +1,12 @@
 // -- Module: <m1-common> --
 package
 
-public final header enum class Bar : kotlin.Enum<Bar> {
-    header enum entry X
+public final expect enum class Bar : kotlin.Enum<Bar> {
+    expect enum entry X
 
-    header enum entry Y
+    expect enum entry Y
 
-    header enum entry Z
+    expect enum entry Z
 
     public final override /*1*/ /*fake_override*/ val name: kotlin.String
     public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
@@ -21,10 +21,10 @@ public final header enum class Bar : kotlin.Enum<Bar> {
     public final /*synthesized*/ fun values(): kotlin.Array<Bar>
 }
 
-public final header enum class Foo : kotlin.Enum<Foo> {
-    header enum entry A
+public final expect enum class Foo : kotlin.Enum<Foo> {
+    expect enum entry A
 
-    header enum entry B
+    expect enum entry B
 
     public final override /*1*/ /*fake_override*/ val name: kotlin.String
     public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
@@ -43,7 +43,7 @@ public final header enum class Foo : kotlin.Enum<Foo> {
 // -- Module: <m2-jvm> --
 package
 
-public final impl enum class Bar : kotlin.Enum<Bar> {
+public final actual enum class Bar : kotlin.Enum<Bar> {
     enum entry V
 
     enum entry X
@@ -70,7 +70,7 @@ public final impl enum class Bar : kotlin.Enum<Bar> {
     public final /*synthesized*/ fun values(): kotlin.Array<Bar>
 }
 
-public final impl enum class Foo : kotlin.Enum<Foo> {
+public final actual enum class Foo : kotlin.Enum<Foo> {
     enum entry A
 
     enum entry B
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.kt b/compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.kt
index f43bf7e8953..a96f43e9f21 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header enum class En<!HEADER_ENUM_CONSTRUCTOR!>(x: Int)<!> {
+expect enum class En<!HEADER_ENUM_CONSTRUCTOR!>(x: Int)<!> {
     E1,
     E2(42),
     ;
@@ -10,6 +10,6 @@ header enum class En<!HEADER_ENUM_CONSTRUCTOR!>(x: Int)<!> {
     <!HEADER_ENUM_CONSTRUCTOR!>constructor(s: String)<!>
 }
 
-header enum class En2 {
+expect enum class En2 {
     E1<!NO_CONSTRUCTOR!>()<!>
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.txt b/compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.txt
index 541b95b4a41..d09f7d8d137 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.txt
@@ -1,9 +1,9 @@
 package
 
-public final header enum class En : kotlin.Enum<En> {
-    header enum entry E1
+public final expect enum class En : kotlin.Enum<En> {
+    expect enum entry E1
 
-    header enum entry E2
+    expect enum entry E2
 
     private constructor En(/*0*/ x: kotlin.Int)
     private constructor En(/*0*/ s: kotlin.String)
@@ -20,8 +20,8 @@ public final header enum class En : kotlin.Enum<En> {
     public final /*synthesized*/ fun values(): kotlin.Array<En>
 }
 
-public final header enum class En2 : kotlin.Enum<En2> {
-    header enum entry E1
+public final expect enum class En2 : kotlin.Enum<En2> {
+    expect enum entry E1
 
     public final override /*1*/ /*fake_override*/ val name: kotlin.String
     public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/differentEntryOrder.kt b/compiler/testData/diagnostics/tests/multiplatform/enum/differentEntryOrder.kt
index 6bdc6f5ff9f..a0928c8d2ed 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/differentEntryOrder.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/differentEntryOrder.kt
@@ -1,10 +1,10 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header enum class Foo { A, B }
-header enum class Bar { X, Y, Z }
+expect enum class Foo { A, B }
+expect enum class Bar { X, Y, Z }
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-impl enum class Foo { B, A }
-impl enum class Bar { X, Z, Y }
+actual enum class Foo { B, A }
+actual enum class Bar { X, Z, Y }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/differentEntryOrder.txt b/compiler/testData/diagnostics/tests/multiplatform/enum/differentEntryOrder.txt
index fa3c9899ff4..ed359015ee1 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/differentEntryOrder.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/differentEntryOrder.txt
@@ -1,12 +1,12 @@
 // -- Module: <m1-common> --
 package
 
-public final header enum class Bar : kotlin.Enum<Bar> {
-    header enum entry X
+public final expect enum class Bar : kotlin.Enum<Bar> {
+    expect enum entry X
 
-    header enum entry Y
+    expect enum entry Y
 
-    header enum entry Z
+    expect enum entry Z
 
     public final override /*1*/ /*fake_override*/ val name: kotlin.String
     public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
@@ -21,10 +21,10 @@ public final header enum class Bar : kotlin.Enum<Bar> {
     public final /*synthesized*/ fun values(): kotlin.Array<Bar>
 }
 
-public final header enum class Foo : kotlin.Enum<Foo> {
-    header enum entry A
+public final expect enum class Foo : kotlin.Enum<Foo> {
+    expect enum entry A
 
-    header enum entry B
+    expect enum entry B
 
     public final override /*1*/ /*fake_override*/ val name: kotlin.String
     public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
@@ -43,7 +43,7 @@ public final header enum class Foo : kotlin.Enum<Foo> {
 // -- Module: <m2-jvm> --
 package
 
-public final impl enum class Bar : kotlin.Enum<Bar> {
+public final actual enum class Bar : kotlin.Enum<Bar> {
     enum entry X
 
     enum entry Z
@@ -66,7 +66,7 @@ public final impl enum class Bar : kotlin.Enum<Bar> {
     public final /*synthesized*/ fun values(): kotlin.Array<Bar>
 }
 
-public final impl enum class Foo : kotlin.Enum<Foo> {
+public final actual enum class Foo : kotlin.Enum<Foo> {
     enum entry B
 
     enum entry A
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/enumEntryWithBody.kt b/compiler/testData/diagnostics/tests/multiplatform/enum/enumEntryWithBody.kt
index 15752d70a8a..cf66d5cb060 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/enumEntryWithBody.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/enumEntryWithBody.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header enum class En {
+expect enum class En {
     E1,
     <!HEADER_ENUM_ENTRY_WITH_BODY!>E2 {
         <!HEADER_DECLARATION_WITH_BODY!>fun foo()<!> = ""
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/enumEntryWithBody.txt b/compiler/testData/diagnostics/tests/multiplatform/enum/enumEntryWithBody.txt
index 5152048b9b1..6180d457022 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/enumEntryWithBody.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/enumEntryWithBody.txt
@@ -1,11 +1,11 @@
 package
 
-public final header enum class En : kotlin.Enum<En> {
-    header enum entry E1
+public final expect enum class En : kotlin.Enum<En> {
+    expect enum entry E1
 
-    header enum entry E2
+    expect enum entry E2
 
-    header enum entry E3
+    expect enum entry E3
 
     public final override /*1*/ /*fake_override*/ val name: kotlin.String
     public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/simpleEnum.kt b/compiler/testData/diagnostics/tests/multiplatform/enum/simpleEnum.kt
index 1ffdff8cb93..853f3029a2c 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/simpleEnum.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/simpleEnum.kt
@@ -1,7 +1,7 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header enum class Foo {
+expect enum class Foo {
     ENTRY1,
     ENTRY2,
     ENTRY3;
@@ -9,7 +9,7 @@ header enum class Foo {
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-impl enum class Foo(val x: String) {
+actual enum class Foo(val x: String) {
     ENTRY1("1"),
     ENTRY2("2"),
     ENTRY3("3");
diff --git a/compiler/testData/diagnostics/tests/multiplatform/enum/simpleEnum.txt b/compiler/testData/diagnostics/tests/multiplatform/enum/simpleEnum.txt
index 0bbcaccdaf5..22a4adc0f28 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/enum/simpleEnum.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/enum/simpleEnum.txt
@@ -1,12 +1,12 @@
 // -- Module: <m1-common> --
 package
 
-public final header enum class Foo : kotlin.Enum<Foo> {
-    header enum entry ENTRY1
+public final expect enum class Foo : kotlin.Enum<Foo> {
+    expect enum entry ENTRY1
 
-    header enum entry ENTRY2
+    expect enum entry ENTRY2
 
-    header enum entry ENTRY3
+    expect enum entry ENTRY3
 
     public final override /*1*/ /*fake_override*/ val name: kotlin.String
     public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
@@ -25,7 +25,7 @@ public final header enum class Foo : kotlin.Enum<Foo> {
 // -- Module: <m2-jvm> --
 package
 
-public final impl enum class Foo : kotlin.Enum<Foo> {
+public final actual enum class Foo : kotlin.Enum<Foo> {
     enum entry ENTRY1
 
     enum entry ENTRY2
diff --git a/compiler/testData/diagnostics/tests/multiplatform/generic/membersInGenericClass.kt b/compiler/testData/diagnostics/tests/multiplatform/generic/membersInGenericClass.kt
index 13542922806..109e6652f72 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/generic/membersInGenericClass.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/generic/membersInGenericClass.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header interface A<T> {
+expect interface A<T> {
     val x: T
     var y: List<T>
     fun f(p: Collection<T>): Map<T, A<T?>>
@@ -11,8 +11,8 @@ header interface A<T> {
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl interface A<T> {
-    impl val x: T
-    impl var y: List<T>
-    impl fun f(p: Collection<T>): Map<T, A<T?>>
+actual interface A<T> {
+    actual val x: T
+    actual var y: List<T>
+    actual fun f(p: Collection<T>): Map<T, A<T?>>
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/generic/membersInGenericClass.txt b/compiler/testData/diagnostics/tests/multiplatform/generic/membersInGenericClass.txt
index dae790fbc1b..35252a9b711 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/generic/membersInGenericClass.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/generic/membersInGenericClass.txt
@@ -1,11 +1,11 @@
 // -- Module: <m1-common> --
 package
 
-public header interface A</*0*/ T> {
-    public header abstract val x: T
-    public header abstract var y: kotlin.collections.List<T>
+public expect interface A</*0*/ T> {
+    public expect abstract val x: T
+    public expect abstract var y: kotlin.collections.List<T>
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public abstract header fun f(/*0*/ p: kotlin.collections.Collection<T>): kotlin.collections.Map<T, A<T?>>
+    public abstract expect fun f(/*0*/ p: kotlin.collections.Collection<T>): kotlin.collections.Map<T, A<T?>>
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
@@ -14,11 +14,11 @@ public header interface A</*0*/ T> {
 // -- Module: <m2-jvm> --
 package
 
-public impl interface A</*0*/ T> {
-    public impl abstract val x: T
-    public impl abstract var y: kotlin.collections.List<T>
+public actual interface A</*0*/ T> {
+    public actual abstract val x: T
+    public actual abstract var y: kotlin.collections.List<T>
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public abstract impl fun f(/*0*/ p: kotlin.collections.Collection<T>): kotlin.collections.Map<T, A<T?>>
+    public abstract actual fun f(/*0*/ p: kotlin.collections.Collection<T>): kotlin.collections.Map<T, A<T?>>
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/classKinds.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/classKinds.kt
index 63294ef03a6..d8f41113255 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/classKinds.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/classKinds.kt
@@ -2,25 +2,25 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header interface Interface
+expect interface Interface
 
-header annotation class Anno(val prop: String)
+expect annotation class Anno(val prop: String)
 
-header object Object
+expect object Object
 
-header class Class
+expect class Class
 
-header enum class En { ENTRY }
+expect enum class En { ENTRY }
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl interface Interface
+actual interface Interface
 
-impl annotation class Anno impl constructor(impl val prop: String)
+actual annotation class Anno actual constructor(actual val prop: String)
 
-impl object Object
+actual object Object
 
-impl class Class
+actual class Class
 
-impl enum class En { ENTRY }
+actual enum class En { ENTRY }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/classKinds.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/classKinds.txt
index be85f31bea5..f0cd22d8ac6 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/classKinds.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/classKinds.txt
@@ -1,23 +1,23 @@
 // -- Module: <m1-common> --
 package
 
-public final header annotation class Anno : kotlin.Annotation {
+public final expect annotation class Anno : kotlin.Annotation {
     public constructor Anno(/*0*/ prop: kotlin.String)
-    public header final val prop: kotlin.String
+    public expect final val prop: kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final header class Class {
+public final expect class Class {
     public constructor Class()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final header enum class En : kotlin.Enum<En> {
-    header enum entry ENTRY
+public final expect enum class En : kotlin.Enum<En> {
+    expect enum entry ENTRY
 
     public final override /*1*/ /*fake_override*/ val name: kotlin.String
     public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
@@ -32,13 +32,13 @@ public final header enum class En : kotlin.Enum<En> {
     public final /*synthesized*/ fun values(): kotlin.Array<En>
 }
 
-public header interface Interface {
+public expect interface Interface {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header object Object {
+public expect object Object {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
@@ -48,22 +48,22 @@ public header object Object {
 // -- Module: <m2-jvm> --
 package
 
-public final impl annotation class Anno : kotlin.Annotation {
+public final actual annotation class Anno : kotlin.Annotation {
     public constructor Anno(/*0*/ prop: kotlin.String)
-    public impl final val prop: kotlin.String
+    public actual final val prop: kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final impl class Class {
+public final actual class Class {
     public constructor Class()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final impl enum class En : kotlin.Enum<En> {
+public final actual enum class En : kotlin.Enum<En> {
     enum entry ENTRY
 
     private constructor En()
@@ -82,13 +82,13 @@ public final impl enum class En : kotlin.Enum<En> {
     public final /*synthesized*/ fun values(): kotlin.Array<En>
 }
 
-public impl interface Interface {
+public actual interface Interface {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public impl object Object {
+public actual object Object {
     private constructor Object()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/explicitConstructorDelegation.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/explicitConstructorDelegation.kt
index a7f95e95ec9..72084e76069 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/explicitConstructorDelegation.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/explicitConstructorDelegation.kt
@@ -1,13 +1,13 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header open class A {
+expect open class A {
     constructor(s: String)
 
     constructor(n: Number) : <!HEADER_CLASS_CONSTRUCTOR_DELEGATION_CALL!>this<!>("A")
 }
 
-header class B : A {
+expect class B : A {
     constructor(i: Int)
 
     constructor() : <!HEADER_CLASS_CONSTRUCTOR_DELEGATION_CALL!>super<!>("B")
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/explicitConstructorDelegation.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/explicitConstructorDelegation.txt
index bba953a0e79..3b48a1aa1bc 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/explicitConstructorDelegation.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/explicitConstructorDelegation.txt
@@ -1,6 +1,6 @@
 package
 
-public open header class A {
+public open expect class A {
     public constructor A(/*0*/ n: kotlin.Number)
     public constructor A(/*0*/ s: kotlin.String)
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -8,7 +8,7 @@ public open header class A {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final header class B : A {
+public final expect class B : A {
     public constructor B()
     public constructor B(/*0*/ i: kotlin.Int)
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.kt
index 5beb9a254b1..ffcd9272a1b 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.kt
@@ -2,13 +2,13 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class H {
-    <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>header<!> fun foo()
+expect class H {
+    <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>expect<!> fun foo()
 }
 
 // MODULE: m1-jvm(m1-common)
 // FILE: jvm.kt
 
-impl class H {
-    impl fun foo() {}
+actual class H {
+    actual fun foo() {}
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.txt
index fef594f44f9..4769b0d0417 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.txt
@@ -1,10 +1,10 @@
 // -- Module: <m1-common> --
 package
 
-public final header class H {
+public final expect class H {
     public constructor H()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final header fun foo(): kotlin.Unit
+    public final expect fun foo(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
@@ -13,10 +13,10 @@ public final header class H {
 // -- Module: <m1-jvm> --
 package
 
-public final impl class H {
+public final actual class H {
     public constructor H()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final impl fun foo(): kotlin.Unit
+    public final actual fun foo(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.kt
index e2a4a69a9f5..388199fecc2 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.kt
@@ -3,29 +3,29 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class C1
-header interface C2<A>
-header interface C3<B>
-header interface C4<D, E>
-header interface C5<F, G>
-header interface C6<H>
-header interface C7<I>
-header interface C8<J>
-header interface C9<K>
-header interface C10<L>
+expect class C1
+expect interface C2<A>
+expect interface C3<B>
+expect interface C4<D, E>
+expect interface C5<F, G>
+expect interface C6<H>
+expect interface C7<I>
+expect interface C8<J>
+expect interface C9<K>
+expect interface C10<L>
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl typealias C1 = String
-<!IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE!>impl typealias C2<<!UNUSED_TYPEALIAS_PARAMETER!>A<!>> = List<String><!>
-<!IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE!>impl typealias C3<B> = List<B><!>
-impl typealias C4<D, E> = MutableMap<D, E>
-<!IMPL_TYPE_ALIAS_WITH_COMPLEX_SUBSTITUTION!>impl typealias C5<F, G> = MutableMap<G, F><!>
-impl typealias C6<H> = MutableList<H>
-<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>impl typealias C7<I> = MutableList<out I><!>
-<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>impl typealias C8<<!UNUSED_TYPEALIAS_PARAMETER!>J<!>> = MutableList<*><!>
-<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>impl typealias C9<K> = MutableList<in K><!>
+actual typealias C1 = String
+<!IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE!>actual typealias C2<<!UNUSED_TYPEALIAS_PARAMETER!>A<!>> = List<String><!>
+<!IMPL_TYPE_ALIAS_TO_CLASS_WITH_DECLARATION_SITE_VARIANCE!>actual typealias C3<B> = List<B><!>
+actual typealias C4<D, E> = MutableMap<D, E>
+<!IMPL_TYPE_ALIAS_WITH_COMPLEX_SUBSTITUTION!>actual typealias C5<F, G> = MutableMap<G, F><!>
+actual typealias C6<H> = MutableList<H>
+<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>actual typealias C7<I> = MutableList<out I><!>
+<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>actual typealias C8<<!UNUSED_TYPEALIAS_PARAMETER!>J<!>> = MutableList<*><!>
+<!IMPL_TYPE_ALIAS_WITH_USE_SITE_VARIANCE!>actual typealias C9<K> = MutableList<in K><!>
 
 typealias Tmp<K> = MutableList<K>
-<!IMPL_TYPE_ALIAS_NOT_TO_CLASS!>impl typealias C10<L> = Tmp<L><!>
+<!IMPL_TYPE_ALIAS_NOT_TO_CLASS!>actual typealias C10<L> = Tmp<L><!>
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.txt
index 67e749d98d2..7027c967f17 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/genericClassImplTypeAlias.txt
@@ -1,62 +1,62 @@
 // -- Module: <m1-common> --
 package
 
-public final header class C1 {
+public final expect class C1 {
     public constructor C1()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C10</*0*/ L> {
+public expect interface C10</*0*/ L> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C2</*0*/ A> {
+public expect interface C2</*0*/ A> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C3</*0*/ B> {
+public expect interface C3</*0*/ B> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C4</*0*/ D, /*1*/ E> {
+public expect interface C4</*0*/ D, /*1*/ E> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C5</*0*/ F, /*1*/ G> {
+public expect interface C5</*0*/ F, /*1*/ G> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C6</*0*/ H> {
+public expect interface C6</*0*/ H> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C7</*0*/ I> {
+public expect interface C7</*0*/ I> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C8</*0*/ J> {
+public expect interface C8</*0*/ J> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public header interface C9</*0*/ K> {
+public expect interface C9</*0*/ K> {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.kt
index 603e112527a..89ac1118e5b 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.kt
@@ -1,7 +1,7 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header class Foo {
+expect class Foo {
     val foo: String
 
     fun bar(x: Int): Int
@@ -9,16 +9,16 @@ header class Foo {
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-impl class Foo {
-    impl val foo: String = "JVM"
+actual class Foo {
+    actual val foo: String = "JVM"
 
-    impl fun bar(x: Int): Int = x + 1
+    actual fun bar(x: Int): Int = x + 1
 }
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
-impl class Foo {
-    impl val foo: String = "JS"
+actual class Foo {
+    actual val foo: String = "JS"
 
-    impl fun bar(x: Int): Int = x - 1
+    actual fun bar(x: Int): Int = x - 1
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.txt
index 0579b60b6db..c4905b14e98 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassMember.txt
@@ -1,10 +1,10 @@
 // -- Module: <m1-common> --
 package
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo()
-    public header final val foo: kotlin.String
-    public final header fun bar(/*0*/ x: kotlin.Int): kotlin.Int
+    public expect final val foo: kotlin.String
+    public final expect fun bar(/*0*/ x: kotlin.Int): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
@@ -14,10 +14,10 @@ public final header class Foo {
 // -- Module: <m2-jvm> --
 package
 
-public final impl class Foo {
+public final actual class Foo {
     public constructor Foo()
-    public impl final val foo: kotlin.String = "JVM"
-    public final impl fun bar(/*0*/ x: kotlin.Int): kotlin.Int
+    public actual final val foo: kotlin.String = "JVM"
+    public final actual fun bar(/*0*/ x: kotlin.Int): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
@@ -27,10 +27,10 @@ public final impl class Foo {
 // -- Module: <m3-js> --
 package
 
-public final impl class Foo {
+public final actual class Foo {
     public constructor Foo()
-    public impl final val foo: kotlin.String = "JS"
-    public final impl fun bar(/*0*/ x: kotlin.Int): kotlin.Int
+    public actual final val foo: kotlin.String = "JS"
+    public final actual fun bar(/*0*/ x: kotlin.Int): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassWithFunctionBody.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassWithFunctionBody.kt
index d33a106589a..a44cf419e53 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassWithFunctionBody.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassWithFunctionBody.kt
@@ -1,7 +1,7 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header class Foo(
+expect class Foo(
         <!HEADER_CLASS_CONSTRUCTOR_PROPERTY_PARAMETER!>val constructorProperty: String<!>,
         constructorParameter: String
 ) {
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassWithFunctionBody.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassWithFunctionBody.txt
index 4d71d652972..049a8ff806e 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassWithFunctionBody.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/headerClassWithFunctionBody.txt
@@ -1,15 +1,15 @@
 package
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo()
     public constructor Foo(/*0*/ s: kotlin.String)
     public constructor Foo(/*0*/ constructorProperty: kotlin.String, /*1*/ constructorParameter: kotlin.String)
-    public header final val constructorProperty: kotlin.String
-    public header final var getSet: kotlin.String
-    public header final val prop: kotlin.String = "no"
-    public final header fun defaultArg(/*0*/ value: kotlin.String = ...): kotlin.Unit
+    public expect final val constructorProperty: kotlin.String
+    public expect final var getSet: kotlin.String
+    public expect final val prop: kotlin.String = "no"
+    public final expect fun defaultArg(/*0*/ value: kotlin.String = ...): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final header fun functionWithBody(/*0*/ x: kotlin.Int): kotlin.Int
+    public final expect fun functionWithBody(/*0*/ x: kotlin.Int): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/implDataClass.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/implDataClass.kt
index ed270f519f8..06bdbf3b645 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/implDataClass.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/implDataClass.kt
@@ -2,14 +2,14 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class Foo(x: Int, y: String) {
+expect class Foo(x: Int, y: String) {
     val x: Int
     val y: String
 }
 
-header class Bar(z: Double)
+expect class Bar(z: Double)
 
-header class Baz(w: List<String>) {
+expect class Baz(w: List<String>) {
     val w: List<String>
 
     operator fun component1(): List<String>
@@ -25,8 +25,8 @@ header class Baz(w: List<String>) {
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl data class Foo impl constructor(impl val x: Int, impl val y: String)
+actual data class Foo actual constructor(actual val x: Int, actual val y: String)
 
-impl data class Bar impl constructor(val z: Double)
+actual data class Bar actual constructor(val z: Double)
 
-impl data class Baz impl constructor(impl val w: List<String>)
+actual data class Baz actual constructor(actual val w: List<String>)
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/implDataClass.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/implDataClass.txt
index d6281db0dd6..291a41f6ea6 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/implDataClass.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/implDataClass.txt
@@ -1,26 +1,26 @@
 // -- Module: <m1-common> --
 package
 
-public final header class Bar {
+public final expect class Bar {
     public constructor Bar(/*0*/ z: kotlin.Double)
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final header class Baz {
+public final expect class Baz {
     public constructor Baz(/*0*/ w: kotlin.collections.List<kotlin.String>)
-    public header final val w: kotlin.collections.List<kotlin.String>
-    public final operator header fun component1(): kotlin.collections.List<kotlin.String>
-    public open header override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open header override /*1*/ fun hashCode(): kotlin.Int
-    public open header override /*1*/ fun toString(): kotlin.String
+    public expect final val w: kotlin.collections.List<kotlin.String>
+    public final operator expect fun component1(): kotlin.collections.List<kotlin.String>
+    public open expect override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open expect override /*1*/ fun hashCode(): kotlin.Int
+    public open expect override /*1*/ fun toString(): kotlin.String
 }
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo(/*0*/ x: kotlin.Int, /*1*/ y: kotlin.String)
-    public header final val x: kotlin.Int
-    public header final val y: kotlin.String
+    public expect final val x: kotlin.Int
+    public expect final val y: kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
@@ -30,7 +30,7 @@ public final header class Foo {
 // -- Module: <m2-jvm> --
 package
 
-public final impl data class Bar {
+public final actual data class Bar {
     public constructor Bar(/*0*/ z: kotlin.Double)
     public final val z: kotlin.Double
     public final operator /*synthesized*/ fun component1(): kotlin.Double
@@ -40,9 +40,9 @@ public final impl data class Bar {
     public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
 }
 
-public final impl data class Baz {
+public final actual data class Baz {
     public constructor Baz(/*0*/ w: kotlin.collections.List<kotlin.String>)
-    public impl final val w: kotlin.collections.List<kotlin.String>
+    public actual final val w: kotlin.collections.List<kotlin.String>
     public final operator /*synthesized*/ fun component1(): kotlin.collections.List<kotlin.String>
     public final /*synthesized*/ fun copy(/*0*/ w: kotlin.collections.List<kotlin.String> = ...): Baz
     public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -50,10 +50,10 @@ public final impl data class Baz {
     public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
 }
 
-public final impl data class Foo {
+public final actual data class Foo {
     public constructor Foo(/*0*/ x: kotlin.Int, /*1*/ y: kotlin.String)
-    public impl final val x: kotlin.Int
-    public impl final val y: kotlin.String
+    public actual final val x: kotlin.Int
+    public actual final val y: kotlin.String
     public final operator /*synthesized*/ fun component1(): kotlin.Int
     public final operator /*synthesized*/ fun component2(): kotlin.String
     public final /*synthesized*/ fun copy(/*0*/ x: kotlin.Int = ..., /*1*/ y: kotlin.String = ...): Foo
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/implOpenClass.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/implOpenClass.kt
index 77cf7fd386e..38b52c8c35d 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/implOpenClass.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/implOpenClass.kt
@@ -2,15 +2,15 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class Foo
+expect class Foo
 
-header fun getFoo(): Foo
+expect fun getFoo(): Foo
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl open class Foo
+actual open class Foo
 
 class Bar : Foo()
 
-impl fun getFoo(): Foo = Bar()
+actual fun getFoo(): Foo = Bar()
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/implOpenClass.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/implOpenClass.txt
index 62872669be1..fc1ef86aa6b 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/implOpenClass.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/implOpenClass.txt
@@ -1,9 +1,9 @@
 // -- Module: <m1-common> --
 package
 
-public header fun getFoo(): Foo
+public expect fun getFoo(): Foo
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -14,7 +14,7 @@ public final header class Foo {
 // -- Module: <m2-jvm> --
 package
 
-public impl fun getFoo(): Foo
+public actual fun getFoo(): Foo
 
 public final class Bar : Foo {
     public constructor Bar()
@@ -23,7 +23,7 @@ public final class Bar : Foo {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public open impl class Foo {
+public open actual class Foo {
     public constructor Foo()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClasses.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClasses.kt
index 2c4dd10c7da..ba17319f3dd 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClasses.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClasses.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class OuterClass {
+expect class OuterClass {
     class NestedClass {
         class DeepNested {
             class Another {
@@ -20,39 +20,39 @@ header class OuterClass {
     companion object
 }
 
-header class OuterClassWithNamedCompanion {
+expect class OuterClassWithNamedCompanion {
     companion object Factory
 }
 
-header object OuterObject {
+expect object OuterObject {
     object NestedObject
 }
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl class OuterClass {
-    impl class NestedClass {
-        impl class DeepNested {
-            impl class Another {
-                impl fun f(s: String) {}
-                impl val p: Int = 42
+actual class OuterClass {
+    actual class NestedClass {
+        actual class DeepNested {
+            actual class Another {
+                actual fun f(s: String) {}
+                actual val p: Int = 42
             }
         }
     }
 
-    impl inner class InnerClass {
-        impl fun f(x: Int) {}
-        impl val p: String = ""
+    actual inner class InnerClass {
+        actual fun f(x: Int) {}
+        actual val p: String = ""
     }
 
-    impl companion object
+    actual companion object
 }
 
-impl class OuterClassWithNamedCompanion {
-    impl companion object Factory
+actual class OuterClassWithNamedCompanion {
+    actual companion object Factory
 }
 
-impl object OuterObject {
-    impl object NestedObject
+actual object OuterObject {
+    actual object NestedObject
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClasses.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClasses.txt
index a83195df542..be81567ef9c 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClasses.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClasses.txt
@@ -1,44 +1,44 @@
 // -- Module: <m1-common> --
 package
 
-public final header class OuterClass {
+public final expect class OuterClass {
     public constructor OuterClass()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public header companion object Companion {
+    public expect companion object Companion {
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    public final header inner class InnerClass {
+    public final expect inner class InnerClass {
         public constructor InnerClass()
-        public header final val p: kotlin.String
+        public expect final val p: kotlin.String
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-        public final header fun f(/*0*/ x: kotlin.Int): kotlin.Unit
+        public final expect fun f(/*0*/ x: kotlin.Int): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    public final header class NestedClass {
+    public final expect class NestedClass {
         public constructor NestedClass()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-        public final header class DeepNested {
+        public final expect class DeepNested {
             public constructor DeepNested()
             public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
             public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
             public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-            public final header class Another {
+            public final expect class Another {
                 public constructor Another()
-                public header final val p: kotlin.Int
+                public expect final val p: kotlin.Int
                 public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-                public final header fun f(/*0*/ s: kotlin.String): kotlin.Unit
+                public final expect fun f(/*0*/ s: kotlin.String): kotlin.Unit
                 public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
                 public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
             }
@@ -46,25 +46,25 @@ public final header class OuterClass {
     }
 }
 
-public final header class OuterClassWithNamedCompanion {
+public final expect class OuterClassWithNamedCompanion {
     public constructor OuterClassWithNamedCompanion()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public header companion object Factory {
+    public expect companion object Factory {
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 }
 
-public header object OuterObject {
+public expect object OuterObject {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public header object NestedObject {
+    public expect object NestedObject {
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
@@ -75,45 +75,45 @@ public header object OuterObject {
 // -- Module: <m2-jvm> --
 package
 
-public final impl class OuterClass {
+public final actual class OuterClass {
     public constructor OuterClass()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public impl companion object Companion {
+    public actual companion object Companion {
         private constructor Companion()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    public final impl inner class InnerClass {
+    public final actual inner class InnerClass {
         public constructor InnerClass()
-        public impl final val p: kotlin.String = ""
+        public actual final val p: kotlin.String = ""
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-        public final impl fun f(/*0*/ x: kotlin.Int): kotlin.Unit
+        public final actual fun f(/*0*/ x: kotlin.Int): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    public final impl class NestedClass {
+    public final actual class NestedClass {
         public constructor NestedClass()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-        public final impl class DeepNested {
+        public final actual class DeepNested {
             public constructor DeepNested()
             public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
             public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
             public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-            public final impl class Another {
+            public final actual class Another {
                 public constructor Another()
-                public impl final val p: kotlin.Int = 42
+                public actual final val p: kotlin.Int = 42
                 public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-                public final impl fun f(/*0*/ s: kotlin.String): kotlin.Unit
+                public final actual fun f(/*0*/ s: kotlin.String): kotlin.Unit
                 public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
                 public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
             }
@@ -121,13 +121,13 @@ public final impl class OuterClass {
     }
 }
 
-public final impl class OuterClassWithNamedCompanion {
+public final actual class OuterClassWithNamedCompanion {
     public constructor OuterClassWithNamedCompanion()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public impl companion object Factory {
+    public actual companion object Factory {
         private constructor Factory()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -135,13 +135,13 @@ public final impl class OuterClassWithNamedCompanion {
     }
 }
 
-public impl object OuterObject {
+public actual object OuterObject {
     private constructor OuterObject()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public impl object NestedObject {
+    public actual object NestedObject {
         private constructor NestedObject()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.kt
index 80b2d641826..ca45328adf7 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.kt
@@ -2,45 +2,45 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class B {
+expect class B {
     class N {
         <!HEADER_DECLARATION_WITH_BODY, JVM:HEADER_DECLARATION_WITH_BODY!>fun body()<!> {}
-        <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>header<!> fun extraHeader()
+        <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>expect<!> fun extraHeader()
     }
 }
 
-header class C {
-    <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>header<!> class N
-    <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>header<!> enum class E
-    <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>header<!> inner class I
+expect class C {
+    <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>expect<!> class N
+    <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>expect<!> enum class E
+    <!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>expect<!> inner class I
 }
 
-header class D {
+expect class D {
     class N
 }
 
-header class E {
+expect class E {
     class N
 }
 
 // MODULE: m1-jvm(m1-common)
 // FILE: jvm.kt
 
-impl class B {
-    impl class N {
-        impl fun body() {}
-        impl fun extraHeader() {}
+actual class B {
+    actual class N {
+        actual fun body() {}
+        actual fun extraHeader() {}
     }
 }
 
-impl class C {
-    impl class N
-    impl enum class E
-    impl inner class I
+actual class C {
+    actual class N
+    actual enum class E
+    actual inner class I
 }
 
-impl class <!HEADER_CLASS_MEMBERS_ARE_NOT_IMPLEMENTED!>D<!>
+actual class <!HEADER_CLASS_MEMBERS_ARE_NOT_IMPLEMENTED!>D<!>
 
-impl class E {
+actual class E {
     class <!IMPL_MISSING!>N<!>
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.txt
index 6ed6fe8c1c3..58b5bb5f34d 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.txt
@@ -1,29 +1,29 @@
 // -- Module: <m1-common> --
 package
 
-public final header class B {
+public final expect class B {
     public constructor B()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final header class N {
+    public final expect class N {
         public constructor N()
-        public final header fun body(): kotlin.Unit
+        public final expect fun body(): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-        public final header fun extraHeader(): kotlin.Unit
+        public final expect fun extraHeader(): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 }
 
-public final header class C {
+public final expect class C {
     public constructor C()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final header enum class E : kotlin.Enum<C.E> {
+    public final expect enum class E : kotlin.Enum<C.E> {
         public final override /*1*/ /*fake_override*/ val name: kotlin.String
         public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
         protected final override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
@@ -37,14 +37,14 @@ public final header class C {
         public final /*synthesized*/ fun values(): kotlin.Array<C.E>
     }
 
-    public final header inner class I {
+    public final expect inner class I {
         public constructor I()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    public final header class N {
+    public final expect class N {
         public constructor N()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -52,13 +52,13 @@ public final header class C {
     }
 }
 
-public final header class D {
+public final expect class D {
     public constructor D()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final header class N {
+    public final expect class N {
         public constructor N()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -66,13 +66,13 @@ public final header class D {
     }
 }
 
-public final header class E {
+public final expect class E {
     public constructor E()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final header class N {
+    public final expect class N {
         public constructor N()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -84,29 +84,29 @@ public final header class E {
 // -- Module: <m1-jvm> --
 package
 
-public final impl class B {
+public final actual class B {
     public constructor B()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final impl class N {
+    public final actual class N {
         public constructor N()
-        public final impl fun body(): kotlin.Unit
+        public final actual fun body(): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-        public final impl fun extraHeader(): kotlin.Unit
+        public final actual fun extraHeader(): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 }
 
-public final impl class C {
+public final actual class C {
     public constructor C()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final impl enum class E : kotlin.Enum<C.E> {
+    public final actual enum class E : kotlin.Enum<C.E> {
         private constructor E()
         public final override /*1*/ /*fake_override*/ val name: kotlin.String
         public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
@@ -123,14 +123,14 @@ public final impl class C {
         public final /*synthesized*/ fun values(): kotlin.Array<C.E>
     }
 
-    public final impl inner class I {
+    public final actual inner class I {
         public constructor I()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    public final impl class N {
+    public final actual class N {
         public constructor N()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -138,14 +138,14 @@ public final impl class C {
     }
 }
 
-public final impl class D {
+public final actual class D {
     public constructor D()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final impl class E {
+public final actual class E {
     public constructor E()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/noImplKeywordOnMember.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/noImplKeywordOnMember.kt
index 7309bdf610f..8dacd9ea6c1 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/noImplKeywordOnMember.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/noImplKeywordOnMember.kt
@@ -2,13 +2,13 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class Foo {
+expect class Foo {
     fun bar(): String
 }
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl class Foo {
+actual class Foo {
     <!IMPL_MISSING!>fun bar(): String<!> = "bar"
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/noImplKeywordOnMember.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/noImplKeywordOnMember.txt
index 23118c90290..36d9992220b 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/noImplKeywordOnMember.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/noImplKeywordOnMember.txt
@@ -1,9 +1,9 @@
 // -- Module: <m1-common> --
 package
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo()
-    public final header fun bar(): kotlin.String
+    public final expect fun bar(): kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
@@ -13,7 +13,7 @@ public final header class Foo {
 // -- Module: <m2-jvm> --
 package
 
-public final impl class Foo {
+public final actual class Foo {
     public constructor Foo()
     public final fun bar(): kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.kt
index 8c19bb12d46..d4032bccead 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.kt
@@ -1,12 +1,12 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header class Foo
+expect class Foo
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-impl class Foo
+actual class Foo
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
-impl class Foo
+actual class Foo
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.txt
index cffcd317ac3..8ce30f1bfff 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/simpleHeaderClass.txt
@@ -1,7 +1,7 @@
 // -- Module: <m1-common> --
 package
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -12,7 +12,7 @@ public final header class Foo {
 // -- Module: <m2-jvm> --
 package
 
-public final impl class Foo {
+public final actual class Foo {
     public constructor Foo()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -23,7 +23,7 @@ public final impl class Foo {
 // -- Module: <m3-js> --
 package
 
-public final impl class Foo {
+public final actual class Foo {
     public constructor Foo()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.kt
index 5f7287771f7..53929912f48 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.kt
@@ -6,12 +6,12 @@ interface I
 open class C
 interface J
 
-header class Foo : I, C, J
+expect class Foo : I, C, J
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-impl class Foo : I, C(), J
+actual class Foo : I, C(), J
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
-impl class Foo : I, J, C()
+actual class Foo : I, J, C()
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.txt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.txt
index 3e30daf255a..266507319ac 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/superClass.txt
@@ -8,7 +8,7 @@ public open class C {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final header class Foo : I, C, J {
+public final expect class Foo : I, C, J {
     public constructor Foo()
     public open override /*3*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*3*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -38,7 +38,7 @@ public open class C {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final impl class Foo : I, C, J {
+public final actual class Foo : I, C, J {
     public constructor Foo()
     public open override /*3*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*3*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -68,7 +68,7 @@ public open class C {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final impl class Foo : I, J, C {
+public final actual class Foo : I, J, C {
     public constructor Foo()
     public open override /*3*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*3*/ /*fake_override*/ fun hashCode(): kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerFunInNonHeaderClass.kt b/compiler/testData/diagnostics/tests/multiplatform/headerFunInNonHeaderClass.kt
index 3f0f1a99da1..b04f0649f28 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerFunInNonHeaderClass.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerFunInNonHeaderClass.kt
@@ -3,7 +3,7 @@
 // FILE: common.kt
 
 class Foo {
-    <!NON_ABSTRACT_FUNCTION_WITH_NO_BODY, JVM:NON_ABSTRACT_FUNCTION_WITH_NO_BODY!><!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>header<!> fun bar(): String<!>
+    <!NON_ABSTRACT_FUNCTION_WITH_NO_BODY, JVM:NON_ABSTRACT_FUNCTION_WITH_NO_BODY!><!WRONG_MODIFIER_TARGET, JVM:WRONG_MODIFIER_TARGET!>expect<!> fun bar(): String<!>
 }
 
 // MODULE: m1-jvm(m1-common)
diff --git a/compiler/testData/diagnostics/tests/multiplatform/implDelegatedMember.kt b/compiler/testData/diagnostics/tests/multiplatform/implDelegatedMember.kt
index 59383edc573..9d3e9381025 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/implDelegatedMember.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/implDelegatedMember.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header open class Foo {
+expect open class Foo {
     open fun bar(): String
 }
 
@@ -16,4 +16,4 @@ interface Bar {
 val bar: Bar
     get() = null!!
 
-impl open class Foo : Bar by bar
+actual open class Foo : Bar by bar
diff --git a/compiler/testData/diagnostics/tests/multiplatform/implDelegatedMember.txt b/compiler/testData/diagnostics/tests/multiplatform/implDelegatedMember.txt
index e39a55d5100..6b5400eb41a 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/implDelegatedMember.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/implDelegatedMember.txt
@@ -1,9 +1,9 @@
 // -- Module: <m1-common> --
 package
 
-public open header class Foo {
+public open expect class Foo {
     public constructor Foo()
-    public open header fun bar(): kotlin.String
+    public open expect fun bar(): kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
@@ -22,7 +22,7 @@ public interface Bar {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public open impl class Foo : Bar {
+public open actual class Foo : Bar {
     public constructor Foo()
     public open override /*1*/ /*delegation*/ fun bar(): kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
diff --git a/compiler/testData/diagnostics/tests/multiplatform/implDynamic.kt b/compiler/testData/diagnostics/tests/multiplatform/implDynamic.kt
index c9f9a65c870..8f5f15bc218 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/implDynamic.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/implDynamic.kt
@@ -3,7 +3,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class Foo {
+expect class Foo {
     constructor(p: Any)
 
     fun f1(s: String): Int
@@ -18,12 +18,12 @@ header class Foo {
 
 // TODO: do not suppress UNSUPPORTED once JS files in multi-platform tests are analyzed with JS analyzer facade
 
-impl class Foo {
-    impl constructor(p: dynamic) {}
+actual class Foo {
+    actual constructor(p: dynamic) {}
 
-    impl fun f1(s: dynamic): dynamic = null!!
+    actual fun f1(s: dynamic): dynamic = null!!
 
-    impl fun f2(s: dynamic): MutableMap<Boolean?, Foo> = null!!
+    actual fun f2(s: dynamic): MutableMap<Boolean?, Foo> = null!!
 
-    impl fun <T : Set<Number>> f3(t: T): dynamic = null!!
+    actual fun <T : Set<Number>> f3(t: T): dynamic = null!!
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/implDynamic.txt b/compiler/testData/diagnostics/tests/multiplatform/implDynamic.txt
index bcf299c0bc9..8ab6fa62475 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/implDynamic.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/implDynamic.txt
@@ -1,12 +1,12 @@
 // -- Module: <m1-common> --
 package
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo(/*0*/ p: kotlin.Any)
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final header fun f1(/*0*/ s: kotlin.String): kotlin.Int
-    public final header fun f2(/*0*/ s: kotlin.collections.List<kotlin.String>?): kotlin.collections.MutableMap<kotlin.Boolean?, Foo>
-    public final header fun </*0*/ T : kotlin.collections.Set<kotlin.Number>> f3(/*0*/ t: T): T?
+    public final expect fun f1(/*0*/ s: kotlin.String): kotlin.Int
+    public final expect fun f2(/*0*/ s: kotlin.collections.List<kotlin.String>?): kotlin.collections.MutableMap<kotlin.Boolean?, Foo>
+    public final expect fun </*0*/ T : kotlin.collections.Set<kotlin.Number>> f3(/*0*/ t: T): T?
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
@@ -15,12 +15,12 @@ public final header class Foo {
 // -- Module: <m2-js> --
 package
 
-public final impl class Foo {
+public final actual class Foo {
     public constructor Foo(/*0*/ p: dynamic)
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final impl fun f1(/*0*/ s: dynamic): dynamic
-    public final impl fun f2(/*0*/ s: dynamic): kotlin.collections.MutableMap<kotlin.Boolean?, Foo>
-    public final impl fun </*0*/ T : kotlin.collections.Set<kotlin.Number>> f3(/*0*/ t: T): dynamic
+    public final actual fun f1(/*0*/ s: dynamic): dynamic
+    public final actual fun f2(/*0*/ s: dynamic): kotlin.collections.MutableMap<kotlin.Boolean?, Foo>
+    public final actual fun </*0*/ T : kotlin.collections.Set<kotlin.Number>> f3(/*0*/ t: T): dynamic
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/implFakeOverride.kt b/compiler/testData/diagnostics/tests/multiplatform/implFakeOverride.kt
index e38b7c8596e..6b0167213e8 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/implFakeOverride.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/implFakeOverride.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class Foo {
+expect class Foo {
     fun bar(): String
 }
 
@@ -13,4 +13,4 @@ open class Bar {
     fun bar() = "bar"
 }
 
-impl class Foo : Bar()
+actual class Foo : Bar()
diff --git a/compiler/testData/diagnostics/tests/multiplatform/implFakeOverride.txt b/compiler/testData/diagnostics/tests/multiplatform/implFakeOverride.txt
index 17e0002a910..48f8386c981 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/implFakeOverride.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/implFakeOverride.txt
@@ -1,9 +1,9 @@
 // -- Module: <m1-common> --
 package
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo()
-    public final header fun bar(): kotlin.String
+    public final expect fun bar(): kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
@@ -21,7 +21,7 @@ public open class Bar {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final impl class Foo : Bar {
+public final actual class Foo : Bar {
     public constructor Foo()
     public final override /*1*/ /*fake_override*/ fun bar(): kotlin.String
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
diff --git a/compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.kt b/compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.kt
index 3cd9824048f..0c9ce6637e0 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class Foo {
+expect class Foo {
     constructor(p: Any)
 
     fun f1(s: String): Int
@@ -29,4 +29,4 @@ public class FooImpl {
 
 // FILE: jvm.kt
 
-impl typealias Foo = FooImpl
+actual typealias Foo = FooImpl
diff --git a/compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.txt b/compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.txt
index 0056a64398c..60f30369e64 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/java/flexibleTypes.txt
@@ -1,12 +1,12 @@
 // -- Module: <m1-common> --
 package
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo(/*0*/ p: kotlin.Any)
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final header fun f1(/*0*/ s: kotlin.String): kotlin.Int
-    public final header fun f2(/*0*/ s: kotlin.collections.List<kotlin.String>?): kotlin.collections.MutableMap<kotlin.Boolean?, Foo>
-    public final header fun </*0*/ T : kotlin.collections.Set<kotlin.Number>> f3(/*0*/ t: T): T?
+    public final expect fun f1(/*0*/ s: kotlin.String): kotlin.Int
+    public final expect fun f2(/*0*/ s: kotlin.collections.List<kotlin.String>?): kotlin.collections.MutableMap<kotlin.Boolean?, Foo>
+    public final expect fun </*0*/ T : kotlin.collections.Set<kotlin.Number>> f3(/*0*/ t: T): T?
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/java/parameterNames.kt b/compiler/testData/diagnostics/tests/multiplatform/java/parameterNames.kt
index 4fb79603210..e20079bebaa 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/java/parameterNames.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/java/parameterNames.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class Foo {
+expect class Foo {
     fun foo(i: Int, d: Double, f: Float): Unit
 }
 
@@ -15,4 +15,4 @@ public class FooImpl {
 
 // FILE: jvm.kt
 
-impl typealias Foo = FooImpl
+actual typealias Foo = FooImpl
diff --git a/compiler/testData/diagnostics/tests/multiplatform/java/parameterNames.txt b/compiler/testData/diagnostics/tests/multiplatform/java/parameterNames.txt
index b52e6de9b59..84ea9f1b764 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/java/parameterNames.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/java/parameterNames.txt
@@ -1,10 +1,10 @@
 // -- Module: <m1-common> --
 package
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final header fun foo(/*0*/ i: kotlin.Int, /*1*/ d: kotlin.Double, /*2*/ f: kotlin.Float): kotlin.Unit
+    public final expect fun foo(/*0*/ i: kotlin.Int, /*1*/ d: kotlin.Double, /*2*/ f: kotlin.Float): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/modifierApplicability.kt b/compiler/testData/diagnostics/tests/multiplatform/modifierApplicability.kt
index 4eaef1e6e8d..711d514652b 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/modifierApplicability.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/modifierApplicability.kt
@@ -2,34 +2,34 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-<!WRONG_MODIFIER_TARGET!>header<!> typealias Foo = String
+<!WRONG_MODIFIER_TARGET!>expect<!> typealias Foo = String
 
-class Outer <!WRONG_MODIFIER_TARGET!>header<!> constructor() {
-    <!WRONG_MODIFIER_TARGET!>header<!> class Nested
+class Outer <!WRONG_MODIFIER_TARGET!>expect<!> constructor() {
+    <!WRONG_MODIFIER_TARGET!>expect<!> class Nested
 
-    <!WRONG_MODIFIER_TARGET!>header<!> init {}
+    <!WRONG_MODIFIER_TARGET!>expect<!> init {}
 
-    <!NON_ABSTRACT_FUNCTION_WITH_NO_BODY!><!WRONG_MODIFIER_TARGET!>header<!> fun foo()<!>
-    <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!><!WRONG_MODIFIER_TARGET!>header<!> val bar: Int<!>
+    <!NON_ABSTRACT_FUNCTION_WITH_NO_BODY!><!WRONG_MODIFIER_TARGET!>expect<!> fun foo()<!>
+    <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!><!WRONG_MODIFIER_TARGET!>expect<!> val bar: Int<!>
 }
 
 fun foo() {
-    <!NON_MEMBER_FUNCTION_NO_BODY!><!WRONG_MODIFIER_TARGET!>header<!> fun localFun()<!>
-    <!WRONG_MODIFIER_TARGET!>header<!> var <!UNUSED_VARIABLE!>x<!> = 42
-    <!WRONG_MODIFIER_TARGET!>header<!> class Bar
+    <!NON_MEMBER_FUNCTION_NO_BODY!><!WRONG_MODIFIER_TARGET!>expect<!> fun localFun()<!>
+    <!WRONG_MODIFIER_TARGET!>expect<!> var <!UNUSED_VARIABLE!>x<!> = 42
+    <!WRONG_MODIFIER_TARGET!>expect<!> class Bar
 }
 
 // MODULE: m2-jvm
 // FILE: jvm.kt
 
-class Outer impl constructor() {
-    impl class <!IMPLEMENTATION_WITHOUT_HEADER!>Nested<!>
+class Outer actual constructor() {
+    actual class <!IMPLEMENTATION_WITHOUT_HEADER!>Nested<!>
 
-    <!WRONG_MODIFIER_TARGET!>impl<!> init {}
+    <!WRONG_MODIFIER_TARGET!>actual<!> init {}
 }
 
 fun foo() {
-    <!WRONG_MODIFIER_TARGET!>impl<!> fun localFun() {}
-    <!WRONG_MODIFIER_TARGET!>impl<!> var <!UNUSED_VARIABLE!>x<!> = 42
-    <!WRONG_MODIFIER_TARGET!>impl<!> class <!IMPLEMENTATION_WITHOUT_HEADER!>Bar<!>
+    <!WRONG_MODIFIER_TARGET!>actual<!> fun localFun() {}
+    <!WRONG_MODIFIER_TARGET!>actual<!> var <!UNUSED_VARIABLE!>x<!> = 42
+    <!WRONG_MODIFIER_TARGET!>actual<!> class <!IMPLEMENTATION_WITHOUT_HEADER!>Bar<!>
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/modifierApplicability.txt b/compiler/testData/diagnostics/tests/multiplatform/modifierApplicability.txt
index 836039dcb3a..c63e7e9da18 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/modifierApplicability.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/modifierApplicability.txt
@@ -11,7 +11,7 @@ public final class Outer {
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final header class Nested {
+    public final expect class Nested {
         public constructor Nested()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
@@ -32,7 +32,7 @@ public final class Outer {
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    public final impl class Nested {
+    public final actual class Nested {
         public constructor Nested()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/namedArguments.kt b/compiler/testData/diagnostics/tests/multiplatform/namedArguments.kt
index 2a968d2dec1..3597f6dbd4e 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/namedArguments.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/namedArguments.kt
@@ -2,13 +2,13 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header class Foo(zzz: Int) {
+expect class Foo(zzz: Int) {
     constructor(aaa: Boolean)
 
     fun f1(xxx: String): String
 }
 
-header fun f2(xxx: Int)
+expect fun f2(xxx: Int)
 
 fun testCommon() {
     Foo(<!NAMED_ARGUMENTS_NOT_ALLOWED!>zzz<!> = 0)
@@ -20,13 +20,13 @@ fun testCommon() {
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl class Foo impl constructor(val aaa: Boolean) {
-    impl constructor(zzz: Int) : this(zzz == 0)
+actual class Foo actual constructor(val aaa: Boolean) {
+    actual constructor(zzz: Int) : this(zzz == 0)
 
-    impl fun f1(xxx: String) = xxx
+    actual fun f1(xxx: String) = xxx
 }
 
-impl fun f2(xxx: Int) {}
+actual fun f2(xxx: Int) {}
 
 fun testPlatform() {
     Foo(zzz = 0)
diff --git a/compiler/testData/diagnostics/tests/multiplatform/namedArguments.txt b/compiler/testData/diagnostics/tests/multiplatform/namedArguments.txt
index 274db482bdd..a092f268878 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/namedArguments.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/namedArguments.txt
@@ -1,14 +1,14 @@
 // -- Module: <m1-common> --
 package
 
-public header fun f2(/*0*/ xxx: kotlin.Int): kotlin.Unit
+public expect fun f2(/*0*/ xxx: kotlin.Int): kotlin.Unit
 public fun testCommon(): kotlin.Unit
 
-public final header class Foo {
+public final expect class Foo {
     public constructor Foo(/*0*/ aaa: kotlin.Boolean)
     public constructor Foo(/*0*/ zzz: kotlin.Int)
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final header fun f1(/*0*/ xxx: kotlin.String): kotlin.String
+    public final expect fun f1(/*0*/ xxx: kotlin.String): kotlin.String
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
@@ -17,16 +17,16 @@ public final header class Foo {
 // -- Module: <m2-jvm> --
 package
 
-public impl fun f2(/*0*/ xxx: kotlin.Int): kotlin.Unit
+public actual fun f2(/*0*/ xxx: kotlin.Int): kotlin.Unit
 public fun testCommon(): kotlin.Unit
 public fun testPlatform(): kotlin.Unit
 
-public final impl class Foo {
+public final actual class Foo {
     public constructor Foo(/*0*/ aaa: kotlin.Boolean)
     public constructor Foo(/*0*/ zzz: kotlin.Int)
     public final val aaa: kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final impl fun f1(/*0*/ xxx: kotlin.String): kotlin.String
+    public final actual fun f1(/*0*/ xxx: kotlin.String): kotlin.String
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/callHeaderFun.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/callHeaderFun.kt
index 4d66760f197..722251b5fc0 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/callHeaderFun.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/callHeaderFun.kt
@@ -2,14 +2,14 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header fun foo(x: Int): Int
+expect fun foo(x: Int): Int
 
 fun callFromCommonCode(x: Int) = foo(x)
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl fun foo(x: Int): Int {
+actual fun foo(x: Int): Int {
     return x + 1
 }
 
@@ -18,7 +18,7 @@ fun callFromJVM(x: Int) = foo(x)
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
 
-impl fun foo(x: Int): Int {
+actual fun foo(x: Int): Int {
     return x - 1
 }
 
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/callHeaderFun.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/callHeaderFun.txt
index cd458e68a81..3253218cf24 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/callHeaderFun.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/callHeaderFun.txt
@@ -2,7 +2,7 @@
 package
 
 public fun callFromCommonCode(/*0*/ x: kotlin.Int): kotlin.Int
-public header fun foo(/*0*/ x: kotlin.Int): kotlin.Int
+public expect fun foo(/*0*/ x: kotlin.Int): kotlin.Int
 
 
 // -- Module: <m2-jvm> --
@@ -10,7 +10,7 @@ package
 
 public fun callFromCommonCode(/*0*/ x: kotlin.Int): kotlin.Int
 public fun callFromJVM(/*0*/ x: kotlin.Int): kotlin.Int
-public impl fun foo(/*0*/ x: kotlin.Int): kotlin.Int
+public actual fun foo(/*0*/ x: kotlin.Int): kotlin.Int
 
 
 // -- Module: <m3-js> --
@@ -18,4 +18,4 @@ package
 
 public fun callFromCommonCode(/*0*/ x: kotlin.Int): kotlin.Int
 public fun callFromJS(/*0*/ x: kotlin.Int): kotlin.Int
-public impl fun foo(/*0*/ x: kotlin.Int): kotlin.Int
+public actual fun foo(/*0*/ x: kotlin.Int): kotlin.Int
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingHeaderDeclarations.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingHeaderDeclarations.kt
index a34b0aa6c40..f60a780381a 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingHeaderDeclarations.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingHeaderDeclarations.kt
@@ -2,7 +2,7 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-<!CONFLICTING_OVERLOADS!>header fun foo()<!>
-<!CONFLICTING_OVERLOADS!>header fun foo()<!>
+<!CONFLICTING_OVERLOADS!>expect fun foo()<!>
+<!CONFLICTING_OVERLOADS!>expect fun foo()<!>
 
-header fun foo(x: Int)
+expect fun foo(x: Int)
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingHeaderDeclarations.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingHeaderDeclarations.txt
index ab106725681..6769c46e7fa 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingHeaderDeclarations.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingHeaderDeclarations.txt
@@ -1,5 +1,5 @@
 package
 
-public header fun foo(): kotlin.Unit
-public header fun foo(): kotlin.Unit
-public header fun foo(/*0*/ x: kotlin.Int): kotlin.Unit
+public expect fun foo(): kotlin.Unit
+public expect fun foo(): kotlin.Unit
+public expect fun foo(/*0*/ x: kotlin.Int): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingImplDeclarations.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingImplDeclarations.kt
index ccb01a86579..f7be9406549 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingImplDeclarations.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingImplDeclarations.kt
@@ -2,16 +2,16 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header fun foo()
+expect fun foo()
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-<!CONFLICTING_OVERLOADS!>impl fun foo()<!> {}
-<!CONFLICTING_OVERLOADS!>impl fun foo()<!> {}
+<!CONFLICTING_OVERLOADS!>actual fun foo()<!> {}
+<!CONFLICTING_OVERLOADS!>actual fun foo()<!> {}
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
 
-<!CONFLICTING_OVERLOADS!>impl fun foo()<!> {}
-<!CONFLICTING_OVERLOADS!>impl fun foo()<!> {}
+<!CONFLICTING_OVERLOADS!>actual fun foo()<!> {}
+<!CONFLICTING_OVERLOADS!>actual fun foo()<!> {}
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingImplDeclarations.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingImplDeclarations.txt
index a1d3524fc3f..71183a4452e 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingImplDeclarations.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/conflictingImplDeclarations.txt
@@ -1,18 +1,18 @@
 // -- Module: <m1-common> --
 package
 
-public header fun foo(): kotlin.Unit
+public expect fun foo(): kotlin.Unit
 
 
 // -- Module: <m2-jvm> --
 package
 
-public impl fun foo(): kotlin.Unit
-public impl fun foo(): kotlin.Unit
+public actual fun foo(): kotlin.Unit
+public actual fun foo(): kotlin.Unit
 
 
 // -- Module: <m3-js> --
 package
 
-public impl fun foo(): kotlin.Unit
-public impl fun foo(): kotlin.Unit
+public actual fun foo(): kotlin.Unit
+public actual fun foo(): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/defaultArguments.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/defaultArguments.kt
index 5d55981ae20..a3508f4bc60 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/defaultArguments.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/defaultArguments.kt
@@ -2,4 +2,4 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header fun foo(x: Int, <!HEADER_DECLARATION_WITH_DEFAULT_PARAMETER!>y: String = ""<!>)
+expect fun foo(x: Int, <!HEADER_DECLARATION_WITH_DEFAULT_PARAMETER!>y: String = ""<!>)
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/defaultArguments.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/defaultArguments.txt
index 127ec370ec2..5e8b0516acb 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/defaultArguments.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/defaultArguments.txt
@@ -1,3 +1,3 @@
 package
 
-public header fun foo(/*0*/ x: kotlin.Int, /*1*/ y: kotlin.String = ...): kotlin.Unit
+public expect fun foo(/*0*/ x: kotlin.Int, /*1*/ y: kotlin.String = ...): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/functionModifiers.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/functionModifiers.kt
index c0d1607e396..4b5982611b2 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/functionModifiers.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/functionModifiers.kt
@@ -3,17 +3,17 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header fun external()
-header fun tailrec()
-header fun inline()
-header fun String.unaryMinus(): String
-header fun String.and(other: String): String
+expect fun external()
+expect fun tailrec()
+expect fun inline()
+expect fun String.unaryMinus(): String
+expect fun String.and(other: String): String
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl external fun external()
-impl tailrec fun tailrec(): Unit = if (true) Unit else tailrec()
-impl inline fun inline() {}
-impl operator fun String.unaryMinus(): String = this
-impl infix fun String.and(other: String): String = this + other
+actual external fun external()
+actual tailrec fun tailrec(): Unit = if (true) Unit else tailrec()
+actual inline fun inline() {}
+actual operator fun String.unaryMinus(): String = this
+actual infix fun String.and(other: String): String = this + other
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/functionModifiers.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/functionModifiers.txt
index 1839e1dcd80..d7f39a9699f 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/functionModifiers.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/functionModifiers.txt
@@ -1,18 +1,18 @@
 // -- Module: <m1-common> --
 package
 
-public header fun external(): kotlin.Unit
-public header fun inline(): kotlin.Unit
-public header fun tailrec(): kotlin.Unit
-public header fun kotlin.String.and(/*0*/ other: kotlin.String): kotlin.String
-public header fun kotlin.String.unaryMinus(): kotlin.String
+public expect fun external(): kotlin.Unit
+public expect fun inline(): kotlin.Unit
+public expect fun tailrec(): kotlin.Unit
+public expect fun kotlin.String.and(/*0*/ other: kotlin.String): kotlin.String
+public expect fun kotlin.String.unaryMinus(): kotlin.String
 
 
 // -- Module: <m2-jvm> --
 package
 
-public external impl fun external(): kotlin.Unit
-public impl inline fun inline(): kotlin.Unit
-public impl tailrec fun tailrec(): kotlin.Unit
-public infix impl fun kotlin.String.and(/*0*/ other: kotlin.String): kotlin.String
-public operator impl fun kotlin.String.unaryMinus(): kotlin.String
+public external actual fun external(): kotlin.Unit
+public actual inline fun inline(): kotlin.Unit
+public actual tailrec fun tailrec(): kotlin.Unit
+public infix actual fun kotlin.String.and(/*0*/ other: kotlin.String): kotlin.String
+public operator actual fun kotlin.String.unaryMinus(): kotlin.String
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.kt
index 9f03f8e5040..a5c8e8dfc90 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.kt
@@ -3,16 +3,16 @@
 // FILE: common.kt
 package common
 
-<!JS:HEADER_WITHOUT_IMPLEMENTATION, JVM:HEADER_WITHOUT_IMPLEMENTATION!>header fun foo()<!>
+<!JS:HEADER_WITHOUT_IMPLEMENTATION, JVM:HEADER_WITHOUT_IMPLEMENTATION!>expect fun foo()<!>
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 package jvm
 
-<!IMPLEMENTATION_WITHOUT_HEADER!>impl fun foo()<!> {}
+<!IMPLEMENTATION_WITHOUT_HEADER!>actual fun foo()<!> {}
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
 package js
 
-<!IMPLEMENTATION_WITHOUT_HEADER!>impl fun foo()<!> {}
+<!IMPLEMENTATION_WITHOUT_HEADER!>actual fun foo()<!> {}
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.txt
index 2ad894bf4b5..79457698488 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerAndImplInDIfferentPackages.txt
@@ -2,7 +2,7 @@
 package
 
 package common {
-    public header fun foo(): kotlin.Unit
+    public expect fun foo(): kotlin.Unit
 }
 
 
@@ -13,7 +13,7 @@ package common {
 }
 
 package jvm {
-    public impl fun foo(): kotlin.Unit
+    public actual fun foo(): kotlin.Unit
 }
 
 
@@ -24,5 +24,5 @@ package common {
 }
 
 package js {
-    public impl fun foo(): kotlin.Unit
+    public actual fun foo(): kotlin.Unit
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerDeclarationWithBody.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerDeclarationWithBody.kt
index 686a0788bf0..fbe117aeea4 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerDeclarationWithBody.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerDeclarationWithBody.kt
@@ -2,8 +2,8 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-<!CONFLICTING_OVERLOADS!>header fun foo()<!>
+<!CONFLICTING_OVERLOADS!>expect fun foo()<!>
 
-<!CONFLICTING_OVERLOADS, HEADER_DECLARATION_WITH_BODY!>header fun foo()<!> {}
+<!CONFLICTING_OVERLOADS, HEADER_DECLARATION_WITH_BODY!>expect fun foo()<!> {}
 
-<!HEADER_DECLARATION_WITH_BODY!>header fun bar()<!> {}
+<!HEADER_DECLARATION_WITH_BODY!>expect fun bar()<!> {}
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerDeclarationWithBody.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerDeclarationWithBody.txt
index cc59f9821de..d062ccfb7fb 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerDeclarationWithBody.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerDeclarationWithBody.txt
@@ -1,5 +1,5 @@
 package
 
-public header fun bar(): kotlin.Unit
-public header fun foo(): kotlin.Unit
-public header fun foo(): kotlin.Unit
+public expect fun bar(): kotlin.Unit
+public expect fun foo(): kotlin.Unit
+public expect fun foo(): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerWithoutImpl.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerWithoutImpl.kt
index e899a3c2bb3..28299c1d935 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerWithoutImpl.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerWithoutImpl.kt
@@ -2,4 +2,4 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header fun foo()
+expect fun foo()
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerWithoutImpl.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerWithoutImpl.txt
index d2f32ce3926..bc95053ff53 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerWithoutImpl.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/headerWithoutImpl.txt
@@ -1,3 +1,3 @@
 package
 
-public header fun foo(): kotlin.Unit
+public expect fun foo(): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implDeclarationWithoutBody.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implDeclarationWithoutBody.kt
index 50582ee05ef..bd79c4f5e43 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implDeclarationWithoutBody.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implDeclarationWithoutBody.kt
@@ -2,11 +2,11 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header fun foo()
+expect fun foo()
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-<!NON_MEMBER_FUNCTION_NO_BODY!>impl fun foo()<!>
+<!NON_MEMBER_FUNCTION_NO_BODY!>actual fun foo()<!>
 
-<!NON_MEMBER_FUNCTION_NO_BODY, IMPLEMENTATION_WITHOUT_HEADER!>impl fun bar()<!>
+<!NON_MEMBER_FUNCTION_NO_BODY, IMPLEMENTATION_WITHOUT_HEADER!>actual fun bar()<!>
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implDeclarationWithoutBody.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implDeclarationWithoutBody.txt
index b1dacf691c1..bfd50ddadbd 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implDeclarationWithoutBody.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implDeclarationWithoutBody.txt
@@ -1,11 +1,11 @@
 // -- Module: <m1-common> --
 package
 
-public header fun foo(): kotlin.Unit
+public expect fun foo(): kotlin.Unit
 
 
 // -- Module: <m2-jvm> --
 package
 
-public impl fun bar(): kotlin.Unit
-public impl fun foo(): kotlin.Unit
+public actual fun bar(): kotlin.Unit
+public actual fun foo(): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implWithoutHeader.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implWithoutHeader.kt
index 1e8e1252d36..dff28271296 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implWithoutHeader.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implWithoutHeader.kt
@@ -2,4 +2,4 @@
 // MODULE: m1-jvm
 // FILE: jvm.kt
 
-<!IMPLEMENTATION_WITHOUT_HEADER!>impl fun foo()<!> { }
+<!IMPLEMENTATION_WITHOUT_HEADER!>actual fun foo()<!> { }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implWithoutHeader.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implWithoutHeader.txt
index 4a9b7153232..b13b1d93193 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implWithoutHeader.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/implWithoutHeader.txt
@@ -1,3 +1,3 @@
 package
 
-public impl fun foo(): kotlin.Unit
+public actual fun foo(): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.kt
index 87d8797a1f4..67e26b4c696 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.kt
@@ -2,17 +2,17 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-inline header fun inlineFun()
-header fun nonInlineFun()
+inline expect fun inlineFun()
+expect fun nonInlineFun()
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-<!IMPLEMENTATION_WITHOUT_HEADER!>impl fun inlineFun()<!> { }
-impl fun nonInlineFun() { }
+<!IMPLEMENTATION_WITHOUT_HEADER!>actual fun inlineFun()<!> { }
+actual fun nonInlineFun() { }
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
 
-impl <!NOTHING_TO_INLINE!>inline<!> fun inlineFun() { }
-impl <!NOTHING_TO_INLINE!>inline<!> fun nonInlineFun() { }
+actual <!NOTHING_TO_INLINE!>inline<!> fun inlineFun() { }
+actual <!NOTHING_TO_INLINE!>inline<!> fun nonInlineFun() { }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.txt
index a83df8f10a3..99bdf29fd28 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/inlineFun.txt
@@ -1,19 +1,19 @@
 // -- Module: <m1-common> --
 package
 
-public header inline fun inlineFun(): kotlin.Unit
-public header fun nonInlineFun(): kotlin.Unit
+public expect inline fun inlineFun(): kotlin.Unit
+public expect fun nonInlineFun(): kotlin.Unit
 
 
 // -- Module: <m2-jvm> --
 package
 
-public impl fun inlineFun(): kotlin.Unit
-public impl fun nonInlineFun(): kotlin.Unit
+public actual fun inlineFun(): kotlin.Unit
+public actual fun nonInlineFun(): kotlin.Unit
 
 
 // -- Module: <m3-js> --
 package
 
-public impl inline fun inlineFun(): kotlin.Unit
-public impl inline fun nonInlineFun(): kotlin.Unit
+public actual inline fun inlineFun(): kotlin.Unit
+public actual inline fun nonInlineFun(): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/simpleHeaderFun.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/simpleHeaderFun.kt
index f29a4d0d38b..a6f7808abf5 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/simpleHeaderFun.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/simpleHeaderFun.kt
@@ -1,12 +1,12 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header fun foo()
+expect fun foo()
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-impl fun foo() {}
+actual fun foo() {}
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
-impl fun foo() {}
+actual fun foo() {}
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/simpleHeaderFun.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/simpleHeaderFun.txt
index 52be88a0c10..fd7094cdc35 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/simpleHeaderFun.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/simpleHeaderFun.txt
@@ -1,16 +1,16 @@
 // -- Module: <m1-common> --
 package
 
-public header fun foo(): kotlin.Unit
+public expect fun foo(): kotlin.Unit
 
 
 // -- Module: <m2-jvm> --
 package
 
-public impl fun foo(): kotlin.Unit
+public actual fun foo(): kotlin.Unit
 
 
 // -- Module: <m3-js> --
 package
 
-public impl fun foo(): kotlin.Unit
+public actual fun foo(): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/valueParameterModifiers.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/valueParameterModifiers.kt
index 87c2a7fc5ea..d615126d400 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/valueParameterModifiers.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/valueParameterModifiers.kt
@@ -3,25 +3,25 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header fun f1(s: () -> String)
-header inline fun f2(s: () -> String)
-header inline fun f3(noinline s: () -> String)
+expect fun f1(s: () -> String)
+expect inline fun f2(s: () -> String)
+expect inline fun f3(noinline s: () -> String)
 
-header fun f4(s: () -> String)
-header inline fun f5(s: () -> String)
-header inline fun f6(crossinline s: () -> String)
+expect fun f4(s: () -> String)
+expect inline fun f5(s: () -> String)
+expect inline fun f6(crossinline s: () -> String)
 
-header fun f7(x: Any)
-header fun f8(vararg x: Any)
+expect fun f7(x: Any)
+expect fun f8(vararg x: Any)
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
 
-impl inline fun f1(noinline s: () -> String) {}
-<!IMPLEMENTATION_WITHOUT_HEADER!>impl inline fun f2(noinline s: () -> String)<!> {}
-impl inline fun f3(s: () -> String) {}
-impl inline fun f4(crossinline s: () -> String) {}
-<!IMPLEMENTATION_WITHOUT_HEADER!>impl inline fun f5(crossinline s: () -> String)<!> {}
-impl inline fun f6(s: () -> String) {}
-<!IMPLEMENTATION_WITHOUT_HEADER!>impl fun f7(vararg x: Any)<!> {}
-<!IMPLEMENTATION_WITHOUT_HEADER!>impl fun f8(x: Any)<!> {}
+actual inline fun f1(noinline s: () -> String) {}
+<!IMPLEMENTATION_WITHOUT_HEADER!>actual inline fun f2(noinline s: () -> String)<!> {}
+actual inline fun f3(s: () -> String) {}
+actual inline fun f4(crossinline s: () -> String) {}
+<!IMPLEMENTATION_WITHOUT_HEADER!>actual inline fun f5(crossinline s: () -> String)<!> {}
+actual inline fun f6(s: () -> String) {}
+<!IMPLEMENTATION_WITHOUT_HEADER!>actual fun f7(vararg x: Any)<!> {}
+<!IMPLEMENTATION_WITHOUT_HEADER!>actual fun f8(x: Any)<!> {}
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/valueParameterModifiers.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/valueParameterModifiers.txt
index a3c04e261ee..11eb0f299aa 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/valueParameterModifiers.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelFun/valueParameterModifiers.txt
@@ -1,24 +1,24 @@
 // -- Module: <m1-common> --
 package
 
-public header fun f1(/*0*/ s: () -> kotlin.String): kotlin.Unit
-public header inline fun f2(/*0*/ s: () -> kotlin.String): kotlin.Unit
-public header inline fun f3(/*0*/ noinline s: () -> kotlin.String): kotlin.Unit
-public header fun f4(/*0*/ s: () -> kotlin.String): kotlin.Unit
-public header inline fun f5(/*0*/ s: () -> kotlin.String): kotlin.Unit
-public header inline fun f6(/*0*/ crossinline s: () -> kotlin.String): kotlin.Unit
-public header fun f7(/*0*/ x: kotlin.Any): kotlin.Unit
-public header fun f8(/*0*/ vararg x: kotlin.Any /*kotlin.Array<out kotlin.Any>*/): kotlin.Unit
+public expect fun f1(/*0*/ s: () -> kotlin.String): kotlin.Unit
+public expect inline fun f2(/*0*/ s: () -> kotlin.String): kotlin.Unit
+public expect inline fun f3(/*0*/ noinline s: () -> kotlin.String): kotlin.Unit
+public expect fun f4(/*0*/ s: () -> kotlin.String): kotlin.Unit
+public expect inline fun f5(/*0*/ s: () -> kotlin.String): kotlin.Unit
+public expect inline fun f6(/*0*/ crossinline s: () -> kotlin.String): kotlin.Unit
+public expect fun f7(/*0*/ x: kotlin.Any): kotlin.Unit
+public expect fun f8(/*0*/ vararg x: kotlin.Any /*kotlin.Array<out kotlin.Any>*/): kotlin.Unit
 
 
 // -- Module: <m2-jvm> --
 package
 
-public impl inline fun f1(/*0*/ noinline s: () -> kotlin.String): kotlin.Unit
-public impl inline fun f2(/*0*/ noinline s: () -> kotlin.String): kotlin.Unit
-public impl inline fun f3(/*0*/ s: () -> kotlin.String): kotlin.Unit
-public impl inline fun f4(/*0*/ crossinline s: () -> kotlin.String): kotlin.Unit
-public impl inline fun f5(/*0*/ crossinline s: () -> kotlin.String): kotlin.Unit
-public impl inline fun f6(/*0*/ s: () -> kotlin.String): kotlin.Unit
-public impl fun f7(/*0*/ vararg x: kotlin.Any /*kotlin.Array<out kotlin.Any>*/): kotlin.Unit
-public impl fun f8(/*0*/ x: kotlin.Any): kotlin.Unit
+public actual inline fun f1(/*0*/ noinline s: () -> kotlin.String): kotlin.Unit
+public actual inline fun f2(/*0*/ noinline s: () -> kotlin.String): kotlin.Unit
+public actual inline fun f3(/*0*/ s: () -> kotlin.String): kotlin.Unit
+public actual inline fun f4(/*0*/ crossinline s: () -> kotlin.String): kotlin.Unit
+public actual inline fun f5(/*0*/ crossinline s: () -> kotlin.String): kotlin.Unit
+public actual inline fun f6(/*0*/ s: () -> kotlin.String): kotlin.Unit
+public actual fun f7(/*0*/ vararg x: kotlin.Any /*kotlin.Array<out kotlin.Any>*/): kotlin.Unit
+public actual fun f8(/*0*/ x: kotlin.Any): kotlin.Unit
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.kt
index 4b228abcb8e..be107a001cf 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.kt
@@ -2,39 +2,39 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-header val justVal: String
-header var justVar: String
+expect val justVal: String
+expect var justVar: String
 
-header val String.extensionVal: Unit
-header var <T> T.genericExtensionVar: T
+expect val String.extensionVal: Unit
+expect var <T> T.genericExtensionVar: T
 
-header val valWithGet: String
+expect val valWithGet: String
     get
-header var varWithGetSet: String
+expect var varWithGetSet: String
     get set
 
-header var varWithPlatformGetSet: String
-    <!WRONG_MODIFIER_TARGET!>header<!> get
-    <!WRONG_MODIFIER_TARGET!>header<!> set
+expect var varWithPlatformGetSet: String
+    <!WRONG_MODIFIER_TARGET!>expect<!> get
+    <!WRONG_MODIFIER_TARGET!>expect<!> set
 
-header val backingFieldVal: String = <!HEADER_PROPERTY_INITIALIZER!>"no"<!>
-header var backingFieldVar: String = <!HEADER_PROPERTY_INITIALIZER!>"no"<!>
+expect val backingFieldVal: String = <!HEADER_PROPERTY_INITIALIZER!>"no"<!>
+expect var backingFieldVar: String = <!HEADER_PROPERTY_INITIALIZER!>"no"<!>
 
-header val customAccessorVal: String
+expect val customAccessorVal: String
     <!HEADER_DECLARATION_WITH_BODY!>get()<!> = "no"
-header var customAccessorVar: String
+expect var customAccessorVar: String
     <!HEADER_DECLARATION_WITH_BODY!>get()<!> = "no"
     <!HEADER_DECLARATION_WITH_BODY!>set(value)<!> {}
 
-header <!CONST_VAL_WITHOUT_INITIALIZER!>const<!> val constVal: Int
+expect <!CONST_VAL_WITHOUT_INITIALIZER!>const<!> val constVal: Int
 
-<!INCOMPATIBLE_MODIFIERS!>header<!> <!INCOMPATIBLE_MODIFIERS!>lateinit<!> var lateinitVar: String
+<!INCOMPATIBLE_MODIFIERS!>expect<!> <!INCOMPATIBLE_MODIFIERS!>lateinit<!> var lateinitVar: String
 
-<!WRONG_MODIFIER_TARGET!>header<!> val delegated: String by Delegate
+<!WRONG_MODIFIER_TARGET!>expect<!> val delegated: String by Delegate
 object Delegate { operator fun getValue(x: Any?, y: Any?): String = "" }
 
 fun test(): String {
-    <!WRONG_MODIFIER_TARGET!>header<!> val localVariable: String
+    <!WRONG_MODIFIER_TARGET!>expect<!> val localVariable: String
     localVariable = "no"
     return localVariable
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.txt
index a4b11c7be2f..6bb2b495c84 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/differentKindsOfProperties.txt
@@ -1,19 +1,19 @@
 package
 
-public header val backingFieldVal: kotlin.String = "no"
-public header var backingFieldVar: kotlin.String
-public const header val constVal: kotlin.Int
-public header val customAccessorVal: kotlin.String
-public header var customAccessorVar: kotlin.String
-public header val delegated: kotlin.String
-public header val justVal: kotlin.String
-public header var justVar: kotlin.String
-public header lateinit var lateinitVar: kotlin.String
-public header val valWithGet: kotlin.String
-public header var varWithGetSet: kotlin.String
-public header var varWithPlatformGetSet: kotlin.String
-public header val kotlin.String.extensionVal: kotlin.Unit
-public header var </*0*/ T> T.genericExtensionVar: T
+public expect val backingFieldVal: kotlin.String = "no"
+public expect var backingFieldVar: kotlin.String
+public const expect val constVal: kotlin.Int
+public expect val customAccessorVal: kotlin.String
+public expect var customAccessorVar: kotlin.String
+public expect val delegated: kotlin.String
+public expect val justVal: kotlin.String
+public expect var justVar: kotlin.String
+public expect lateinit var lateinitVar: kotlin.String
+public expect val valWithGet: kotlin.String
+public expect var varWithGetSet: kotlin.String
+public expect var varWithPlatformGetSet: kotlin.String
+public expect val kotlin.String.extensionVal: kotlin.Unit
+public expect var </*0*/ T> T.genericExtensionVar: T
 public fun test(): kotlin.String
 
 public object Delegate {
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/simpleHeaderVar.kt b/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/simpleHeaderVar.kt
index 5c7c627f335..5f0401c080f 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/simpleHeaderVar.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/simpleHeaderVar.kt
@@ -1,12 +1,12 @@
 // !LANGUAGE: +MultiPlatformProjects
 // MODULE: m1-common
 // FILE: common.kt
-header var foo: String
+expect var foo: String
 
 // MODULE: m2-jvm(m1-common)
 // FILE: jvm.kt
-impl var foo: String = "JVM"
+actual var foo: String = "JVM"
 
 // MODULE: m3-js(m1-common)
 // FILE: js.kt
-impl var foo: String = "JS"
+actual var foo: String = "JS"
diff --git a/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/simpleHeaderVar.txt b/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/simpleHeaderVar.txt
index 5b6876f1611..ef55dea0593 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/simpleHeaderVar.txt
+++ b/compiler/testData/diagnostics/tests/multiplatform/topLevelProperty/simpleHeaderVar.txt
@@ -1,16 +1,16 @@
 // -- Module: <m1-common> --
 package
 
-public header var foo: kotlin.String
+public expect var foo: kotlin.String
 
 
 // -- Module: <m2-jvm> --
 package
 
-public impl var foo: kotlin.String
+public actual var foo: kotlin.String
 
 
 // -- Module: <m3-js> --
 package
 
-public impl var foo: kotlin.String
+public actual var foo: kotlin.String
diff --git a/compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.kt b/compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.kt
index 64a5b8f3c76..cf0dd55cd50 100644
--- a/compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.kt
+++ b/compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.kt
@@ -1,7 +1,7 @@
-<!UNSUPPORTED_FEATURE!>header<!> fun foo1()
-<!UNSUPPORTED_FEATURE!>header<!> val bar1 = <!HEADER_PROPERTY_INITIALIZER!>42<!>
-<!UNSUPPORTED_FEATURE!>header<!> class Baz1
+<!UNSUPPORTED_FEATURE!>expect<!> fun foo1()
+<!UNSUPPORTED_FEATURE!>expect<!> val bar1 = <!HEADER_PROPERTY_INITIALIZER!>42<!>
+<!UNSUPPORTED_FEATURE!>expect<!> class Baz1
 
-<!UNSUPPORTED_FEATURE!>impl<!> fun foo2() = 42
-<!MUST_BE_INITIALIZED!><!UNSUPPORTED_FEATURE!>impl<!> val bar2: Int<!>
-<!UNSUPPORTED_FEATURE!>impl<!> interface Baz2
+<!UNSUPPORTED_FEATURE!>actual<!> fun foo2() = 42
+<!MUST_BE_INITIALIZED!><!UNSUPPORTED_FEATURE!>actual<!> val bar2: Int<!>
+<!UNSUPPORTED_FEATURE!>actual<!> interface Baz2
diff --git a/compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.txt b/compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.txt
index d4c08aabe52..adc6296102d 100644
--- a/compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.txt
+++ b/compiler/testData/diagnostics/tests/sourceCompatibility/noMultiplatformProjects.txt
@@ -1,9 +1,9 @@
 package
 
-public impl val bar2: kotlin.Int
-public impl fun foo2(): kotlin.Int
+public actual val bar2: kotlin.Int
+public actual fun foo2(): kotlin.Int
 
-public impl interface Baz2 {
+public actual interface Baz2 {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String