Annotate $default-method with same annotations as original

#KT-6930 Fixed

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

@@ -169,9 +169,7 @@ public class FunctionCodegen {
             v.getSerializationBindings().put(METHOD_FOR_FUNCTION, functionDescriptor, asmMethod);
         }
 
-        AnnotationCodegen.forMethod(mv, typeMapper).genAnnotations(functionDescriptor, asmMethod.getReturnType());
-
-        generateParameterAnnotations(functionDescriptor, mv, jvmSignature);
+        generateAnnotationsForMethod(functionDescriptor, asmMethod, mv, true);
 
         if (state.getClassBuilderMode() != ClassBuilderMode.LIGHT_CLASSES) {
             generateJetValueParameterAnnotations(mv, functionDescriptor, jvmSignature);
@@ -218,10 +216,21 @@ public class FunctionCodegen {
         methodContext.recordSyntheticAccessorIfNeeded(functionDescriptor, bindingContext);
     }
 
+    private void generateAnnotationsForMethod(
+            @NotNull FunctionDescriptor functionDescriptor,
+            Method asmMethod,
+            MethodVisitor mv,
+            boolean recordParametersIndices
+    ) {
+        AnnotationCodegen.forMethod(mv, typeMapper).genAnnotations(functionDescriptor, asmMethod.getReturnType());
+        generateParameterAnnotations(functionDescriptor, mv, typeMapper.mapSignature(functionDescriptor), recordParametersIndices);
+    }
+
     private void generateParameterAnnotations(
             @NotNull FunctionDescriptor functionDescriptor,
             @NotNull MethodVisitor mv,
-            @NotNull JvmMethodSignature jvmSignature
+            @NotNull JvmMethodSignature jvmSignature,
+            boolean recordParametersIndices
     ) {
         Iterator<ValueParameterDescriptor> iterator = functionDescriptor.getValueParameters().iterator();
         List<JvmMethodParameterSignature> kotlinParameterTypes = jvmSignature.getValueParameters();
@@ -236,7 +245,9 @@ public class FunctionCodegen {
 
             if (kind == JvmMethodParameterKind.VALUE) {
                 ValueParameterDescriptor parameter = iterator.next();
-                v.getSerializationBindings().put(INDEX_FOR_VALUE_PARAMETER, parameter, i);
+                if (recordParametersIndices) {
+                    v.getSerializationBindings().put(INDEX_FOR_VALUE_PARAMETER, parameter, i);
+                }
                 AnnotationCodegen.forParameter(i, mv, typeMapper).genAnnotations(parameter, parameterSignature.getAsmType());
             }
         }
@@ -603,6 +614,8 @@ public class FunctionCodegen {
                 getThrownExceptions(functionDescriptor, typeMapper)
         );
 
+        generateAnnotationsForMethod(functionDescriptor, defaultMethod, mv, false);
+
         if (state.getClassBuilderMode() == ClassBuilderMode.FULL) {
             if (this.owner instanceof PackageFacadeContext) {
                 mv.visitCode();

compiler/testData/codegen/boxWithStdlib/annotations/annotationsOnDefault.kt

@@ -0,0 +1,43 @@
+import java.lang.annotation.*
+import kotlin.reflect.jvm.java
+import kotlin.test.assertEquals
+
+Retention(RetentionPolicy.RUNTIME)
+annotation class Ann(val x: Int)
+class A {
+    Ann(1) fun foo(Ann(2) x: Int, y: Int = 2, Ann(3) z: Int) {}
+
+    Ann(1) constructor(Ann(2) x: Int, y: Int = 2, Ann(3) z: Int)
+}
+
+class B [Ann(1)] (Ann(2) x: Int, y: Int = 2, Ann(3) z: Int) {}
+
+fun Array<out Annotation>.ann() = filterIsInstance<Ann>()
+
+fun test(name: String, annotations: Array<out Annotation>, parameters: Array<out Array<out Annotation>>) {
+    assertEquals(1, annotations.ann()[0].x, "$name[0]")
+
+    assertEquals(2, parameters[0].ann()[0].x, "$name-param[0]")
+    assertEquals(0, parameters[1].ann().size(), "$name-param[1]")
+    assertEquals(3, parameters[2].ann()[0].x, "$name-param[2]")
+}
+
+fun box(): String {
+    val foo = javaClass<A>().getDeclaredMethods().first { it.getName() == "foo" }
+    test("foo", foo.getDeclaredAnnotations(), foo.getParameterAnnotations())
+
+    val fooDefault = javaClass<A>().getDeclaredMethods().first { it.getName() == "foo\$default" }
+    test("foo", foo.getDeclaredAnnotations(), foo.getParameterAnnotations())
+
+    val (secondary, secondaryDefault) = javaClass<A>().getDeclaredConstructors().partition { it.getParameterTypes().size() == 3 }
+
+    test("secondary", secondary[0].getDeclaredAnnotations(), secondary[0].getParameterAnnotations())
+    test("secondary\$default", secondaryDefault[0].getDeclaredAnnotations(), secondaryDefault[0].getParameterAnnotations())
+
+    val (primary, primaryDefault) = javaClass<B>().getConstructors().partition { it.getParameterTypes().size() == 3 }
+
+    test("primary", primary[0].getDeclaredAnnotations(), primary[0].getParameterAnnotations())
+    test("secondary\$default", primaryDefault[0].getDeclaredAnnotations(), primaryDefault[0].getParameterAnnotations())
+
+    return "OK"
+}

compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxWithStdlibCodegenTestGenerated.java

@@ -49,6 +49,12 @@ public class BlackBoxWithStdlibCodegenTestGenerated extends AbstractBlackBoxCode
             doTestWithStdlib(fileName);
         }
 
+        @TestMetadata("annotationsOnDefault.kt")
+        public void testAnnotationsOnDefault() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxWithStdlib/annotations/annotationsOnDefault.kt");
+            doTestWithStdlib(fileName);
+        }
+
         @TestMetadata("defaultParameterValues.kt")
         public void testDefaultParameterValues() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxWithStdlib/annotations/defaultParameterValues.kt");