[FIR] Fix computing compatibility of expect and actual modality

compiler/testData/diagnostics/tests/multiplatform/expectObjectWithAbstractMember.kt

@@ -0,0 +1,18 @@
+// FIR_IDENTICAL
+// MODULE: m1-common
+// FILE: common.kt
+
+interface Base {
+    fun foo()
+}
+
+expect object Implementation : Base
+
+// MODULE: m1-jvm()()(m1-common)
+// FILE: jvm.kt
+
+abstract class RealImplementation : Base {
+    override fun foo() {}
+}
+
+actual object Implementation : RealImplementation(), Base

compiler/testData/diagnostics/tests/multiplatform/expectObjectWithAbstractMember.txt

@@ -0,0 +1,43 @@
+// -- Module: <m1-common> --
+package
+
+public interface Base {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract 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 object Implementation : Base {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final 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
+}
+
+// -- Module: <m1-jvm> --
+package
+
+public interface Base {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract 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 actual object Implementation : RealImplementation, Base {
+    private constructor Implementation()
+    public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*2*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public abstract class RealImplementation : Base {
+    public constructor RealImplementation()
+    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/equalsOverrideInActualInterface.kt

@@ -0,0 +1,8 @@
+// FIR_IDENTICAL
+// MODULE: m1-common
+expect interface Base
+
+// MODULE: m1-jvm()()(m1-common)
+actual interface Base {
+    override fun equals(other: Any?): Boolean
+}

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

@@ -0,0 +1,18 @@
+// -- Module: <m1-common> --
+package
+
+public expect interface Base {
+    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
+}
+
+// -- Module: <m1-jvm> --
+package
+
+public actual interface Base {
+    public abstract override /*1*/ 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
+}
+