Map proper owner for method with default args

compiler/backend/src/org/jetbrains/kotlin/codegen/state/KotlinTypeMapper.java

@@ -658,7 +658,9 @@ public class KotlinTypeMapper {
 
             baseMethodDescriptor = findBaseDeclaration(functionDescriptor).getOriginal();
             ClassDescriptor ownerForDefault = (ClassDescriptor) baseMethodDescriptor.getContainingDeclaration();
-            ownerForDefaultImpl = isJvmInterface(ownerForDefault) ? mapDefaultImpls(ownerForDefault) : mapClass(ownerForDefault);
+            ownerForDefaultImpl =
+                    isJvmInterface(ownerForDefault) && (state == null || !isJvm8Interface(ownerForDefault, state)) ?
+                    mapDefaultImpls(ownerForDefault) : mapClass(ownerForDefault);
 
             if (isInterface && (superCall || descriptor.getVisibility() == Visibilities.PRIVATE || isAccessor(descriptor))) {
                 thisClass = mapClass(currentOwner);

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

@@ -0,0 +1,13 @@
+// JVM_TARGET: 1.8
+
+interface Z {
+    fun test(s: String = "OK"): String {
+        return s
+    }
+}
+
+class Test: Z
+
+fun box(): String {
+    return Test().test()
+}

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

@@ -139,6 +139,12 @@ public class BlackBoxWithJava8CodegenTestGenerated extends AbstractBlackBoxCodeg
             doTest(fileName);
         }
 
+        @TestMetadata("defaultArgs.kt")
+        public void testDefaultArgs() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/java8/box/jvm8/defaultArgs.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("diamond.kt")
         public void testDiamond() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/java8/box/jvm8/diamond.kt");