Deprecate non-const properties copies in interface

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

@@ -786,10 +786,13 @@ public class AsmUtil {
     }
 
     public static boolean isPropertyWithBackingFieldCopyInOuterClass(@NotNull PropertyDescriptor propertyDescriptor) {
+        boolean isExtensionProperty = propertyDescriptor.getExtensionReceiverParameter() != null;
         DeclarationDescriptor propertyContainer = propertyDescriptor.getContainingDeclaration();
-        return propertyDescriptor.isConst()
-               && isInterfaceCompanionObject(propertyContainer)
-               && propertyDescriptor.getVisibility() == Visibilities.PUBLIC;
+        return !propertyDescriptor.isVar()
+               && !isExtensionProperty
+               && isCompanionObject(propertyContainer) && isInterface(propertyContainer.getContainingDeclaration())
+               && areBothAccessorDefault(propertyDescriptor)
+               && getVisibilityForSpecialPropertyBackingField(propertyDescriptor, false) == ACC_PUBLIC;
     }
 
     public static boolean isCompanionObjectWithBackingFieldsInOuter(@NotNull DeclarationDescriptor companionObject) {

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

@@ -1024,8 +1024,9 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
             PropertyDescriptor property = info.descriptor;
 
             Type type = typeMapper.mapType(property);
+            int modifiers = ACC_STATIC | ACC_FINAL | ACC_PUBLIC | (property.isConst() ? 0 : ACC_DEPRECATED);
             FieldVisitor fv = v.newField(Synthetic(DescriptorToSourceUtils.descriptorToDeclaration(property), property),
-                                         ACC_STATIC | ACC_FINAL | ACC_PUBLIC, context.getFieldName(property, false),
+                                         modifiers, context.getFieldName(property, false),
                                          type.getDescriptor(), typeMapper.mapFieldSignature(property.getType()),
                                          info.defaultValue);
 

compiler/testData/codegen/boxWithJava/properties/classObjectProperties/Test.java

@@ -8,8 +8,11 @@ class Test {
         s = Trait.NAME;
         if (!s.equals("Trait")) throw new AssertionError("Fail interface: " + s);
 
+        s = Trait.DEPRECATED;
+        if (!s.equals("DEPRECATED")) throw new AssertionError("Fail interface: " + s);
+
         s = Enoom.NAME;
-        if (!s.equals("Enoom")) throw new AssertionError("Fail enum: " + s);
+        if (!s.equals("Enum")) throw new AssertionError("Fail enum: " + s);
 
         return "OK";
     }

compiler/testData/codegen/boxWithJava/properties/classObjectProperties/classObjectProperties.kt

@@ -7,13 +7,14 @@ class Klass {
 interface Trait {
     companion object {
         const val NAME = "Trait"
+        val DEPRECATED = "DEPRECATED"
     }
 }
 
 enum class Enoom {
     ;
     companion object {
-        const val NAME = "Enoom"
+        const val NAME = "Enum"
     }
 }
 

compiler/testData/writeFlags/property/classObject/trait/internalConstVal.kt

@@ -6,7 +6,7 @@ interface Test {
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test, prop
-// ABSENT: TRUE
+// FLAGS: ACC_PUBLIC, ACC_FINAL, ACC_STATIC
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test$Companion, prop

compiler/testData/writeFlags/property/classObject/trait/internalVal.kt

@@ -6,7 +6,7 @@ interface Test {
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test, prop
-// ABSENT: TRUE
+// FLAGS: ACC_PUBLIC, ACC_FINAL, ACC_STATIC, ACC_DEPRECATED
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test$Companion, prop

compiler/testData/writeFlags/property/classObject/trait/publicVal.kt

@@ -6,7 +6,7 @@ interface Test {
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test, prop
-// ABSENT: TRUE
+// FLAGS: ACC_PUBLIC, ACC_FINAL, ACC_STATIC, ACC_DEPRECATED
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test$Companion, prop