Don't generate delegates on overriding jvm8 interfaces

compiler/backend/src/org/jetbrains/kotlin/codegen/ImplementationBodyCodegen.java

@@ -1326,7 +1326,7 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
         for (Map.Entry<FunctionDescriptor, FunctionDescriptor> entry : CodegenUtil.getNonPrivateTraitMethods(descriptor).entrySet()) {
             FunctionDescriptor traitFun = entry.getKey();
             //skip java 8 default methods
-            if (!(traitFun instanceof JavaCallableMemberDescriptor)) {
+            if (!(traitFun instanceof JavaCallableMemberDescriptor || isJvm8InterfaceMember(traitFun, state))) {
                 generateDelegationToTraitImpl(traitFun, entry.getValue());
             }
         }

compiler/backend/src/org/jetbrains/kotlin/codegen/JvmCodegenUtil.java

@@ -28,11 +28,11 @@ import org.jetbrains.kotlin.codegen.context.CodegenContext;
 import org.jetbrains.kotlin.codegen.context.FacadePartWithSourceFile;
 import org.jetbrains.kotlin.codegen.context.MethodContext;
 import org.jetbrains.kotlin.codegen.context.RootContext;
+import org.jetbrains.kotlin.codegen.state.GenerationState;
 import org.jetbrains.kotlin.codegen.state.KotlinTypeMapper;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.load.java.descriptors.JavaPropertyDescriptor;
-import org.jetbrains.kotlin.load.kotlin.ModuleMapping;
-import org.jetbrains.kotlin.load.kotlin.ModuleVisibilityUtilsKt;
+import org.jetbrains.kotlin.load.kotlin.*;
 import org.jetbrains.kotlin.psi.Call;
 import org.jetbrains.kotlin.psi.KtFile;
 import org.jetbrains.kotlin.psi.KtFunction;
@@ -43,7 +43,9 @@ import org.jetbrains.kotlin.resolve.DescriptorUtils;
 import org.jetbrains.kotlin.resolve.inline.InlineUtil;
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue;
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedCallableMemberDescriptor;
+import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedClassDescriptor;
 import org.jetbrains.kotlin.types.KotlinType;
+import org.jetbrains.org.objectweb.asm.Opcodes;
 
 import java.io.File;
 
@@ -58,6 +60,32 @@ public class JvmCodegenUtil {
     private JvmCodegenUtil() {
     }
 
+    public static boolean isJvm6Interface(@NotNull DeclarationDescriptor descriptor, @NotNull GenerationState state) {
+        if (!DescriptorUtils.isInterface(descriptor)) {
+            return false;
+        }
+
+        if (descriptor instanceof DeserializedClassDescriptor) {
+            SourceElement source = ((DeserializedClassDescriptor) descriptor).getSource();
+            if (source instanceof KotlinJvmBinarySourceElement) {
+                KotlinJvmBinaryClass binaryClass = ((KotlinJvmBinarySourceElement) source).getBinaryClass();
+                assert binaryClass instanceof FileBasedKotlinClass :
+                        "KotlinJvmBinaryClass should be subclass of FileBasedKotlinClass, but " + binaryClass;
+                return ((FileBasedKotlinClass) binaryClass).getClassVersion() == Opcodes.V1_6;
+            }
+        }
+        return !state.isJvm8Target();
+    }
+
+    public static boolean isJvm8Interface(@NotNull DeclarationDescriptor descriptor, @NotNull GenerationState state) {
+        return DescriptorUtils.isInterface(descriptor) && !isJvm6Interface(descriptor, state);
+    }
+
+    public static boolean isJvm8InterfaceMember(@NotNull CallableMemberDescriptor descriptor, @NotNull GenerationState state) {
+        DeclarationDescriptor declaration = descriptor.getContainingDeclaration();
+        return DescriptorUtils.isInterface(declaration) && !isJvm6Interface(declaration, state);
+    }
+
     public static boolean isJvmInterface(DeclarationDescriptor descriptor) {
         if (descriptor instanceof ClassDescriptor) {
             ClassKind kind = ((ClassDescriptor) descriptor).getKind();

compiler/testData/codegen/java8/box/jvm8/noDelegation/noDelegationToDefaultMethodInClass.kt

@@ -0,0 +1,21 @@
+// KOTLIN_CONFIGURATION_FLAGS: +JVM.JVM_8_TARGET
+// WITH_RUNTIME
+// FULL_JDK
+interface Test {
+    fun test() {
+    }
+}
+
+class TestClass : Test {
+
+}
+
+fun box(): String {
+    try {
+        TestClass::class.java.getDeclaredMethod("test")
+    }
+    catch (e: NoSuchMethodException) {
+        return "OK"
+    }
+    return "fail"
+}

compiler/testData/codegen/java8/box/jvm8/noDelegation/noDelegationToDefaultMethodInInterface.kt

@@ -0,0 +1,21 @@
+// KOTLIN_CONFIGURATION_FLAGS: +JVM.JVM_8_TARGET
+// WITH_RUNTIME
+// FULL_JDK
+interface Test {
+    fun test() {
+    }
+}
+
+interface Test2 : Test {
+
+}
+
+fun box(): String {
+    try {
+        Test2::class.java.getDeclaredMethod("test")
+    }
+    catch (e: NoSuchMethodException) {
+        return "OK"
+    }
+    return "fail"
+}

compiler/testData/codegen/java8/box/jvm8/noDelegation/noDelegationToDefaultMethodInInterface2.kt

@@ -0,0 +1,25 @@
+// KOTLIN_CONFIGURATION_FLAGS: +JVM.JVM_8_TARGET
+// WITH_RUNTIME
+// FULL_JDK
+interface Test {
+    fun test() {
+    }
+}
+
+interface Test2 : Test {
+
+}
+
+interface Test3 : Test2 {
+
+}
+
+fun box(): String {
+    try {
+        Test3::class.java.getDeclaredMethod("test")
+    }
+    catch (e: NoSuchMethodException) {
+        return "OK"
+    }
+    return "fail"
+}

compiler/testData/codegen/java8/box/jvm8/simpleCall.kt

@@ -0,0 +1,14 @@
+// KOTLIN_CONFIGURATION_FLAGS: +JVM.JVM_8_TARGET
+interface Test {
+    fun test(): String {
+        return "OK"
+    }
+}
+
+class TestClass : Test {
+
+}
+
+fun box(): String {
+    return TestClass().test()
+}

compiler/tests-java8/tests/org/jetbrains/kotlin/codegen/BlackBoxWithJava8CodegenTestGenerated.java

@@ -119,6 +119,48 @@ public class BlackBoxWithJava8CodegenTestGenerated extends AbstractBlackBoxCodeg
         doTest(fileName);
     }
 
+    @TestMetadata("compiler/testData/codegen/java8/box/jvm8")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class Jvm8 extends AbstractBlackBoxCodegenTest {
+        public void testAllFilesPresentInJvm8() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/java8/box/jvm8"), Pattern.compile("^(.+)\\.kt$"), true);
+        }
+
+        @TestMetadata("simpleCall.kt")
+        public void testSimpleCall() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/java8/box/jvm8/simpleCall.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("compiler/testData/codegen/java8/box/jvm8/noDelegation")
+        @TestDataPath("$PROJECT_ROOT")
+        @RunWith(JUnit3RunnerWithInners.class)
+        public static class NoDelegation extends AbstractBlackBoxCodegenTest {
+            public void testAllFilesPresentInNoDelegation() throws Exception {
+                KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/java8/box/jvm8/noDelegation"), Pattern.compile("^(.+)\\.kt$"), true);
+            }
+
+            @TestMetadata("noDelegationToDefaultMethodInClass.kt")
+            public void testNoDelegationToDefaultMethodInClass() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/java8/box/jvm8/noDelegation/noDelegationToDefaultMethodInClass.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("noDelegationToDefaultMethodInInterface.kt")
+            public void testNoDelegationToDefaultMethodInInterface() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/java8/box/jvm8/noDelegation/noDelegationToDefaultMethodInInterface.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("noDelegationToDefaultMethodInInterface2.kt")
+            public void testNoDelegationToDefaultMethodInInterface2() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/java8/box/jvm8/noDelegation/noDelegationToDefaultMethodInInterface2.kt");
+                doTest(fileName);
+            }
+        }
+    }
+
     @TestMetadata("compiler/testData/codegen/java8/box/mapRemove")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)