Improve fake override construction for expected classes

Fake overrides for abstract members from expected classes should become
non-abstract (final, in fact) in non-abstract expected subclasses

 #KT-22031 Fixed

compiler/testData/diagnostics/tests/multiplatform/headerClass/extendExpectedClassWithAbstractMember.kt

@@ -0,0 +1,55 @@
+// !LANGUAGE: +MultiPlatformProjects
+// MODULE: m1-common
+// FILE: common.kt
+
+expect abstract class BaseA() {
+    abstract fun foo()
+}
+expect open class BaseAImpl() : BaseA
+
+class DerivedA1 : BaseAImpl()
+class DerivedA2 : BaseAImpl() {
+    <!OVERRIDING_FINAL_MEMBER!>override<!> fun foo() = super.foo()
+}
+
+
+
+expect interface BaseB {
+    fun foo()
+}
+expect open class BaseBImpl() : BaseB
+
+class DerivedB1 : BaseBImpl()
+class DerivedB2 : BaseBImpl() {
+    <!OVERRIDING_FINAL_MEMBER!>override<!> fun foo() = super.foo()
+}
+
+
+
+expect interface BaseC {
+    fun foo()
+}
+expect abstract class BaseCImpl() : BaseC
+
+<!ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED!>class DerivedC1<!> : BaseCImpl()
+class DerivedC2 : BaseCImpl() {
+    override fun foo() = super.<!ABSTRACT_SUPER_CALL!>foo<!>()
+}
+
+
+
+expect interface BaseD {
+    fun foo()
+}
+abstract class BaseDImpl() : BaseD {
+    fun bar() = super.<!ABSTRACT_SUPER_CALL!>foo<!>()
+}
+
+
+
+expect interface BaseE {
+    fun foo()
+}
+sealed class BaseEImpl() : BaseE {
+    fun bar() = super.<!ABSTRACT_SUPER_CALL!>foo<!>()
+}

compiler/testData/diagnostics/tests/multiplatform/headerClass/extendExpectedClassWithAbstractMember.txt

@@ -0,0 +1,127 @@
+package
+
+public abstract expect class BaseA {
+    public constructor BaseA()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract 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
+}
+
+public open expect class BaseAImpl : BaseA {
+    public constructor BaseAImpl()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public expect interface BaseB {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract 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
+}
+
+public open expect class BaseBImpl : BaseB {
+    public constructor BaseBImpl()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public expect interface BaseC {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract 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
+}
+
+public abstract expect class BaseCImpl : BaseC {
+    public constructor BaseCImpl()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public expect interface BaseD {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract 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
+}
+
+public abstract class BaseDImpl : BaseD {
+    public constructor BaseDImpl()
+    public final fun bar(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public expect interface BaseE {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract 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
+}
+
+public sealed class BaseEImpl : BaseE {
+    private constructor BaseEImpl()
+    public final fun bar(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class DerivedA1 : BaseAImpl {
+    public constructor DerivedA1()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class DerivedA2 : BaseAImpl {
+    public constructor DerivedA2()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class DerivedB1 : BaseBImpl {
+    public constructor DerivedB1()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class DerivedB2 : BaseBImpl {
+    public constructor DerivedB2()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class DerivedC1 : BaseCImpl {
+    public constructor DerivedC1()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class DerivedC2 : BaseCImpl {
+    public constructor DerivedC2()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/multiplatform/headerClass/extendExpectedClassWithoutExplicitOverrideOfMethod.txt

@@ -24,7 +24,7 @@ public final expect class DerivedExplicitCheck : Base {
 
 public final expect class DerivedImplicit : Base {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public abstract expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public final expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }