Allow data classes to implement equals/hashCode/toString from base classes

#KT-11306 Fixed

compiler/testData/diagnostics/tests/dataClasses/finalMembersInBaseClass.kt

@@ -0,0 +1,16 @@
+abstract class Base {
+    final override fun equals(other: Any?) = false
+    final override fun hashCode() = 42
+
+    open override fun toString() = "OK"
+}
+
+data class Data1(val field: String) : Base()
+
+interface AbstractAnyMembers {
+    abstract override fun equals(other: Any?): Boolean
+    abstract override fun hashCode(): Int
+    abstract override fun toString(): String
+}
+
+data class Data2(val field: String): Base(), AbstractAnyMembers

compiler/testData/diagnostics/tests/dataClasses/finalMembersInBaseClass.txt

@@ -0,0 +1,34 @@
+package
+
+public interface AbstractAnyMembers {
+    public abstract override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ fun hashCode(): kotlin.Int
+    public abstract override /*1*/ fun toString(): kotlin.String
+}
+
+public abstract class Base {
+    public constructor Base()
+    public final override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final override /*1*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ fun toString(): kotlin.String
+}
+
+public final data class Data1 : Base {
+    public constructor Data1(/*0*/ field: kotlin.String)
+    public final val field: kotlin.String
+    public final operator /*synthesized*/ fun component1(): kotlin.String
+    public final /*synthesized*/ fun copy(/*0*/ field: kotlin.String = ...): Data1
+    public final override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+public final data class Data2 : Base, AbstractAnyMembers {
+    public constructor Data2(/*0*/ field: kotlin.String)
+    public final val field: kotlin.String
+    public final operator /*synthesized*/ fun component1(): kotlin.String
+    public final /*synthesized*/ fun copy(/*0*/ field: kotlin.String = ...): Data2
+    public final override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*2*/ /*synthesized*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/dataClasses/implementMethodsFromInterface.kt

@@ -0,0 +1,25 @@
+// KT-11306 ABSTRACT_MEMBER_NOT_IMPLEMENTED for data class should inheriting interfaces requiring equals(), hashCode(), or toString()
+
+interface Foo {
+    override fun equals(other: Any?): Boolean
+    override fun hashCode(): Int
+    override fun toString(): String
+}
+
+data class FooImpl(val num: Int) : Foo
+
+data class FooImplSome(val num: Int) : Foo {
+    override fun hashCode() = 42
+}
+
+data class FooImplAll(val num: Int) : Foo {
+    override fun equals(other: Any?) = false
+    override fun hashCode() = 42
+    override fun toString() = "OK"
+}
+
+
+data class WrongSignatures(val num: Int) : Foo {
+    <!NOTHING_TO_OVERRIDE!>override<!> fun equals(other: WrongSignatures) = false
+    override fun hashCode(): <!RETURN_TYPE_MISMATCH_ON_OVERRIDE!>Boolean<!> = true
+}

compiler/testData/diagnostics/tests/dataClasses/implementMethodsFromInterface.txt

@@ -0,0 +1,48 @@
+package
+
+public interface Foo {
+    public abstract override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ fun hashCode(): kotlin.Int
+    public abstract override /*1*/ fun toString(): kotlin.String
+}
+
+public final data class FooImpl : Foo {
+    public constructor FooImpl(/*0*/ num: kotlin.Int)
+    public final val num: kotlin.Int
+    public final operator /*synthesized*/ fun component1(): kotlin.Int
+    public final /*synthesized*/ fun copy(/*0*/ num: kotlin.Int = ...): FooImpl
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+public final data class FooImplAll : Foo {
+    public constructor FooImplAll(/*0*/ num: kotlin.Int)
+    public final val num: kotlin.Int
+    public final operator /*synthesized*/ fun component1(): kotlin.Int
+    public final /*synthesized*/ fun copy(/*0*/ num: kotlin.Int = ...): FooImplAll
+    public open override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ fun toString(): kotlin.String
+}
+
+public final data class FooImplSome : Foo {
+    public constructor FooImplSome(/*0*/ num: kotlin.Int)
+    public final val num: kotlin.Int
+    public final operator /*synthesized*/ fun component1(): kotlin.Int
+    public final /*synthesized*/ fun copy(/*0*/ num: kotlin.Int = ...): FooImplSome
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+public final data class WrongSignatures : Foo {
+    public constructor WrongSignatures(/*0*/ num: kotlin.Int)
+    public final val num: kotlin.Int
+    public final operator /*synthesized*/ fun component1(): kotlin.Int
+    public final /*synthesized*/ fun copy(/*0*/ num: kotlin.Int = ...): WrongSignatures
+    public open fun equals(/*0*/ other: WrongSignatures): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun hashCode(): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}