JVM_IR: in InheritedDefaultMethodsOnClassesLowering, skip bridges when resolving overrides

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/InheritedDefaultMethodsOnClassesLowering.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.backend.common.ir.passTypeArgumentsFrom
 import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
+import org.jetbrains.kotlin.backend.jvm.JvmLoweredDeclarationOrigin
 import org.jetbrains.kotlin.backend.jvm.codegen.isJvmInterface
 import org.jetbrains.kotlin.backend.jvm.ir.createDelegatingCallWithPlaceholderTypeArguments
 import org.jetbrains.kotlin.backend.jvm.ir.createPlaceholderAnyNType
@@ -219,15 +220,23 @@ private class InterfaceObjectCallsLowering(val context: JvmBackendContext) : IrE
  * interface implementation should be generated into the class containing the fake override; or null if the given function is not a fake
  * override of any interface implementation or such method was already generated into the superclass or is a method from Any.
  */
+private fun isDefaultImplsBridge(f: IrSimpleFunction) =
+        f.origin == JvmLoweredDeclarationOrigin.DEFAULT_IMPLS_BRIDGE ||
+        f.origin == JvmLoweredDeclarationOrigin.DEFAULT_IMPLS_BRIDGE_TO_SYNTHETIC
+
 internal fun IrSimpleFunction.findInterfaceImplementation(): IrSimpleFunction? {
     if (!isFakeOverride) return null
     parent.let { if (it is IrClass && it.isJvmInterface) return null }
 
-    val implementation = resolveFakeOverride() ?: return null
+    val implementation = resolveFakeOverride(toSkip = ::isDefaultImplsBridge) ?: return null
 
     // Only generate interface delegation for functions immediately inherited from an interface.
     // (Otherwise, delegation will be present in the parent class)
-    if (overriddenSymbols.any { !it.owner.parentAsClass.isInterface && it.owner.modality != Modality.ABSTRACT && it.owner.resolveFakeOverride() == implementation }) {
+    if (overriddenSymbols.any {
+            !it.owner.parentAsClass.isInterface &&
+                    it.owner.modality != Modality.ABSTRACT &&
+                    it.owner.resolveFakeOverride(toSkip = ::isDefaultImplsBridge) == implementation
+        }) {
         return null
     }
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrUtils.kt

@@ -260,8 +260,8 @@ fun IrClass.isSubclassOf(ancestor: IrClass): Boolean {
     return this.hasAncestorInSuperTypes()
 }
 
-fun IrSimpleFunction.collectRealOverrides(): Set<IrSimpleFunction> {
-    if (isReal) return setOf(this)
+fun IrSimpleFunction.collectRealOverrides(toSkip: (IrSimpleFunction) -> Boolean = { false }): Set<IrSimpleFunction> {
+    if (isReal && !toSkip(this)) return setOf(this)
 
     val visited = mutableSetOf<IrSimpleFunction>()
     val realOverrides = mutableSetOf<IrSimpleFunction>()
@@ -269,7 +269,7 @@ fun IrSimpleFunction.collectRealOverrides(): Set<IrSimpleFunction> {
     fun collectRealOverrides(func: IrSimpleFunction) {
         if (!visited.add(func)) return
 
-        if (func.isReal) {
+        if (func.isReal && !toSkip(func)) {
             realOverrides += func
         } else {
             func.overriddenSymbols.forEach { collectRealOverrides(it.owner) }
@@ -295,8 +295,8 @@ fun IrSimpleFunction.collectRealOverrides(): Set<IrSimpleFunction> {
 
 // This implementation is from kotlin-native
 // TODO: use this implementation instead of any other
-fun IrSimpleFunction.resolveFakeOverride(): IrSimpleFunction? {
-    return collectRealOverrides().singleOrNull { it.modality != Modality.ABSTRACT }
+fun IrSimpleFunction.resolveFakeOverride(toSkip: (IrSimpleFunction) -> Boolean = { false }): IrSimpleFunction? {
+    return collectRealOverrides(toSkip).singleOrNull { it.modality != Modality.ABSTRACT }
 }
 
 fun IrSimpleFunction.isOrOverridesSynthesized(): Boolean {

compiler/testData/codegen/box/traits/doubleDiamond.kt

@@ -0,0 +1,19 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+
+interface A {
+    val result: String get() = "Fail"
+}
+
+interface B : A
+
+abstract class AImpl : A
+
+abstract class BImpl : AImpl(), B
+
+interface C : B {
+    override val result: String get() = "OK"
+}
+
+object CImpl : BImpl(), C
+
+fun box(): String = CImpl.result

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -28052,6 +28052,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/traits/diamondPropertyAccessors.kt");
         }
 
+        @TestMetadata("doubleDiamond.kt")
+        public void testDoubleDiamond() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/doubleDiamond.kt");
+        }
+
         @TestMetadata("genericMethod.kt")
         public void testGenericMethod() throws Exception {
             runTest("compiler/testData/codegen/box/traits/genericMethod.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -26869,6 +26869,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/traits/diamondPropertyAccessors.kt");
         }
 
+        @TestMetadata("doubleDiamond.kt")
+        public void testDoubleDiamond() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/doubleDiamond.kt");
+        }
+
         @TestMetadata("genericMethod.kt")
         public void testGenericMethod() throws Exception {
             runTest("compiler/testData/codegen/box/traits/genericMethod.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -26556,6 +26556,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/traits/diamondPropertyAccessors.kt");
         }
 
+        @TestMetadata("doubleDiamond.kt")
+        public void testDoubleDiamond() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/doubleDiamond.kt");
+        }
+
         @TestMetadata("genericMethod.kt")
         public void testGenericMethod() throws Exception {
             runTest("compiler/testData/codegen/box/traits/genericMethod.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -26556,6 +26556,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/traits/diamondPropertyAccessors.kt");
         }
 
+        @TestMetadata("doubleDiamond.kt")
+        public void testDoubleDiamond() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/doubleDiamond.kt");
+        }
+
         @TestMetadata("genericMethod.kt")
         public void testGenericMethod() throws Exception {
             runTest("compiler/testData/codegen/box/traits/genericMethod.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -21567,6 +21567,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/traits/diamondPropertyAccessors.kt");
         }
 
+        @TestMetadata("doubleDiamond.kt")
+        public void testDoubleDiamond() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/doubleDiamond.kt");
+        }
+
         @TestMetadata("genericMethod.kt")
         public void testGenericMethod() throws Exception {
             runTest("compiler/testData/codegen/box/traits/genericMethod.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -21627,6 +21627,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/traits/diamondPropertyAccessors.kt");
         }
 
+        @TestMetadata("doubleDiamond.kt")
+        public void testDoubleDiamond() throws Exception {
+            runTest("compiler/testData/codegen/box/traits/doubleDiamond.kt");
+        }
+
         @TestMetadata("genericMethod.kt")
         public void testGenericMethod() throws Exception {
             runTest("compiler/testData/codegen/box/traits/genericMethod.kt");