[K/N][codegen] Fix for https://youtrack.jetbrains.com/issue/KT-48543

Sometimes an interface contains final methods, they shouldn't be in its itable
cause they can't be called virtually

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/descriptors/ClassLayoutBuilder.kt

@@ -49,7 +49,6 @@ internal class OverriddenFunctionInfo(
                 && function.bridgeDirectionsTo(overriddenFunction).allNotNeeded()
 
     fun getImplementation(context: Context): IrSimpleFunction? {
-
         val target = function.target
         val implementation = if (!needBridge)
             target
@@ -351,8 +350,11 @@ internal class ClassLayoutBuilder(val irClass: IrClass, val context: Context, va
 
     val interfaceVTableEntries: List<IrSimpleFunction> by lazy {
         require(irClass.isInterface)
-        irClass.overridableOrOverridingMethods
+        irClass.simpleFunctions()
-                .filter { f -> f.isReal || f.overriddenSymbols.any { f.needBridgeTo(it.owner) } }
+                .filter { f ->
+                    f.isOverridable && f.bridgeTarget == null
+                            && (f.isReal || f.overriddenSymbols.any { f.needBridgeTo(it.owner) })
+                }
                 .sortedBy { it.uniqueName }
     }
 

kotlin-native/backend.native/tests/build.gradle

@@ -2971,6 +2971,10 @@ task interfaceCallsNCasts_functionNameClash(type: KonanLocalTest) {
     source = "codegen/interfaceCallsNCasts/functionNameClash.kt"
 }
 
+task interfaceCallsNCasts_finalMethod(type: KonanLocalTest) {
+    source = "codegen/interfaceCallsNCasts/finalMethod.kt"
+}
+
 task interfaceCallsNCasts_diamond(type: KonanLocalTest) {
     source = "codegen/interfaceCallsNCasts/diamond.kt"
 }

kotlin-native/backend.native/tests/codegen/interfaceCallsNCasts/finalMethod.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+package codegen.interfaceCallsNCasts.finalMethod
+
+import kotlin.test.*
+
+interface I1<T> {
+    fun defaultX(): T
+    fun foo(x: T = defaultX()): T
+}
+
+interface I2 : I1<Int> {
+
+}
+
+class C : I2 {
+    override fun defaultX() = 42
+    override fun foo(x: Int) = x
+}
+
+@Test
+fun runTest() {
+    val c: I2 = C()
+    assertEquals(42, c.foo())
+}