Fix support for @OverrideInit constructors with default arguments

#KT-41910 Fixed

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt

@@ -186,7 +186,7 @@ private class InteropLoweringPart1(val context: Context) : BaseInteropIrTransfor
                 it is IrProperty && it.annotations.hasAnnotation(interop.objCOutlet.fqNameSafe) ->
                         generateOutletSetterImp(it)
 
-                it is IrConstructor && it.annotations.hasAnnotation(interop.objCOverrideInit.fqNameSafe) ->
+                it is IrConstructor && it.isOverrideInit() ->
                         generateOverrideInit(irClass, it)
 
                 else -> null
@@ -199,6 +199,17 @@ private class InteropLoweringPart1(val context: Context) : BaseInteropIrTransfor
         }
     }
 
+    private fun IrConstructor.isOverrideInit(): Boolean {
+        if (this.origin != IrDeclarationOrigin.DEFINED) {
+            // Make best efforts to skip generated stubs that might have got annotations
+            // copied from original declarations.
+            // For example, default argument stubs (https://youtrack.jetbrains.com/issue/KT-41910).
+            return false
+        }
+
+        return this.annotations.hasAnnotation(context.interopBuiltIns.objCOverrideInit.fqNameSafe)
+    }
+
     private fun generateOverrideInit(irClass: IrClass, constructor: IrConstructor): IrSimpleFunction {
         val superClass = irClass.getSuperClassNotAny()!!
         val superConstructors = superClass.constructors.filter {

backend.native/tests/interop/objc/tests/overrideInit.kt

@@ -2,10 +2,21 @@ import kotlinx.cinterop.*
 import kotlin.test.*
 import objcTests.*
 
-@Test fun testOverrideInit() {
-    assertEquals(42, (TestOverrideInitImpl.createWithValue(42) as TestOverrideInitImpl).value)
+@Test fun testOverrideInit1() {
+    assertEquals(42, (TestOverrideInitImpl1.createWithValue(42) as TestOverrideInitImpl1).value)
 }
 
-private class TestOverrideInitImpl @OverrideInit constructor(val value: Int) : TestOverrideInit(value) {
+private class TestOverrideInitImpl1 @OverrideInit constructor(val value: Int) : TestOverrideInit(value) {
+    companion object : TestOverrideInitMeta()
+}
+
+// See https://youtrack.jetbrains.com/issue/KT-41910
+@Test fun testOverrideInitWithDefaultArguments() {
+    assertEquals(42, (TestOverrideInitImpl2.createWithValue(42) as TestOverrideInitImpl2).value)
+    assertEquals(123, TestOverrideInitImpl2(123).value)
+    assertEquals(17, TestOverrideInitImpl2().value)
+}
+
+private class TestOverrideInitImpl2 @OverrideInit constructor(val value: Int = 17) : TestOverrideInit(value) {
     companion object : TestOverrideInitMeta()
 }