JVM IR: do not generate certain special bridges as final

Special bridges which are generated as a replacement for a non-final
fake override and use invokespecial to call the already existing
implementation in the superclass, should not be final. Otherwise we
can't generate an override for the original Kotlin function in a
subclass with the same JVM signature.

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

@@ -136,7 +136,8 @@ private class BridgeLowering(val context: JvmBackendContext) : FileLoweringPass,
         val signature: Method,
         val specializedReturnType: IrType? = null,
         val methodInfo: SpecialMethodWithDefaultInfo? = null,
-        val superQualifierSymbol: IrClassSymbol? = null
+        val superQualifierSymbol: IrClassSymbol? = null,
+        val isFinal: Boolean = true,
     )
 
     override fun lower(irFile: IrFile) = irFile.transformChildrenVoid()
@@ -229,7 +230,8 @@ private class BridgeLowering(val context: JvmBackendContext) : FileLoweringPass,
                             val superTarget = irFunction.overriddenSymbols.first { !it.owner.parentAsClass.isInterface }.owner
                             val superBridge = SpecialBridge(
                                 irFunction, irFunction.jvmMethod, superQualifierSymbol = superTarget.parentAsClass.symbol,
-                                methodInfo = specialBridge.methodInfo?.copy(argumentsToCheck = 0) // For potential argument boxing
+                                methodInfo = specialBridge.methodInfo?.copy(argumentsToCheck = 0), // For potential argument boxing
+                                isFinal = false,
                             )
                             irClass.declarations.remove(irFunction)
                             irClass.addSpecialBridge(superBridge, superTarget)
@@ -366,8 +368,7 @@ private class BridgeLowering(val context: JvmBackendContext) : FileLoweringPass,
 
     private fun IrClass.addSpecialBridge(specialBridge: SpecialBridge, target: IrSimpleFunction): IrSimpleFunction =
         addFunction {
-            // FIXME: This seems to be a work-around for superfluous specialized collection stubs
-            modality = if (!target.isCollectionStub()) Modality.FINAL else Modality.OPEN
+            modality = if (specialBridge.isFinal) Modality.FINAL else Modality.OPEN
             origin = IrDeclarationOrigin.BRIDGE_SPECIAL
             name = Name.identifier(specialBridge.signature.name)
             returnType = specialBridge.specializedReturnType ?: specialBridge.overridden.returnType.eraseTypeParameters()
@@ -490,7 +491,4 @@ private class BridgeLowering(val context: JvmBackendContext) : FileLoweringPass,
         get() = context.methodSignatureMapper.mapAsmMethod(this)
 }
 
-private fun IrSimpleFunction.isCollectionStub(): Boolean =
-    origin == IrDeclarationOrigin.IR_BUILTINS_STUB
-
 private fun IrDeclaration.comesFromJava() = parentAsClass.origin == IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB

compiler/testData/codegen/box/specialBuiltins/specialBridgeModality.kt

@@ -0,0 +1,17 @@
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND_FIR: JVM_IR
+
+import java.util.AbstractMap
+
+// Neither of getSize, getKeys, getEntries, getValues generated here should be final.
+abstract class AbstractMutableMap<K, V> : MutableMap<K, V>, AbstractMap<K, V>()
+
+class MyMap<K, V> : AbstractMutableMap<K, V>() {
+    override val size: Int
+        get() = 1
+    override val entries: MutableSet<MutableMap.MutableEntry<K, V>>
+        get() = null!!
+}
+
+fun box(): String =
+    if (MyMap<String, String>().size == 1) "OK" else "Fail"

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

@@ -27216,6 +27216,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/specialBuiltins/removeSetInt.kt");
         }
 
+        @TestMetadata("specialBridgeModality.kt")
+        public void testSpecialBridgeModality() throws Exception {
+            runTest("compiler/testData/codegen/box/specialBuiltins/specialBridgeModality.kt");
+        }
+
         @TestMetadata("throwable.kt")
         public void testThrowable() throws Exception {
             runTest("compiler/testData/codegen/box/specialBuiltins/throwable.kt");

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

@@ -26033,6 +26033,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/specialBuiltins/removeSetInt.kt");
         }
 
+        @TestMetadata("specialBridgeModality.kt")
+        public void testSpecialBridgeModality() throws Exception {
+            runTest("compiler/testData/codegen/box/specialBuiltins/specialBridgeModality.kt");
+        }
+
         @TestMetadata("throwable.kt")
         public void testThrowable() throws Exception {
             runTest("compiler/testData/codegen/box/specialBuiltins/throwable.kt");

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

@@ -25720,6 +25720,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/specialBuiltins/removeSetInt.kt");
         }
 
+        @TestMetadata("specialBridgeModality.kt")
+        public void testSpecialBridgeModality() throws Exception {
+            runTest("compiler/testData/codegen/box/specialBuiltins/specialBridgeModality.kt");
+        }
+
         @TestMetadata("throwable.kt")
         public void testThrowable() throws Exception {
             runTest("compiler/testData/codegen/box/specialBuiltins/throwable.kt");

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

@@ -25720,6 +25720,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/specialBuiltins/removeSetInt.kt");
         }
 
+        @TestMetadata("specialBridgeModality.kt")
+        public void testSpecialBridgeModality() throws Exception {
+            runTest("compiler/testData/codegen/box/specialBuiltins/specialBridgeModality.kt");
+        }
+
         @TestMetadata("throwable.kt")
         public void testThrowable() throws Exception {
             runTest("compiler/testData/codegen/box/specialBuiltins/throwable.kt");