diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/AsmUtil.java b/compiler/backend/src/org/jetbrains/kotlin/codegen/AsmUtil.java
index 129569b396f..48d5666d73f 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/AsmUtil.java
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/AsmUtil.java
@@ -758,14 +758,8 @@ public class AsmUtil {
     }
 
     public static int getVisibilityForSpecialPropertyBackingField(@NotNull PropertyDescriptor propertyDescriptor, boolean isDelegate) {
-        return getVisibilityForSpecialPropertyBackingField(propertyDescriptor, isDelegate, false);
-    }
-
-    public static int getVisibilityForSpecialPropertyBackingField(@NotNull PropertyDescriptor propertyDescriptor, boolean isDelegate, boolean skipInterfaceCheck) {
         boolean isExtensionProperty = propertyDescriptor.getExtensionReceiverParameter() != null;
-        if (isDelegate ||
-            isExtensionProperty ||
-            (!skipInterfaceCheck && isInterfaceCompanionObject(propertyDescriptor.getContainingDeclaration()))) {
+        if (isDelegate || isExtensionProperty) {
             return ACC_PRIVATE;
         }
         else {
@@ -785,13 +779,10 @@ public class AsmUtil {
     }
 
     public static boolean isPropertyWithBackingFieldCopyInOuterClass(@NotNull PropertyDescriptor propertyDescriptor) {
-        boolean isExtensionProperty = propertyDescriptor.getExtensionReceiverParameter() != null;
         DeclarationDescriptor propertyContainer = propertyDescriptor.getContainingDeclaration();
-        return !propertyDescriptor.isVar()
-               && !isExtensionProperty
-               && isCompanionObject(propertyContainer) && isInterface(propertyContainer.getContainingDeclaration())
-               && areBothAccessorDefault(propertyDescriptor)
-               && getVisibilityForSpecialPropertyBackingField(propertyDescriptor, false, true) == ACC_PUBLIC;
+        return propertyDescriptor.isConst()
+               && isInterfaceCompanionObject(propertyContainer)
+               && propertyDescriptor.getVisibility() == Visibilities.PUBLIC;
     }
 
     public static boolean isCompanionObjectWithBackingFieldsInOuter(@NotNull DeclarationDescriptor companionObject) {
diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/PropertyCodegen.java b/compiler/backend/src/org/jetbrains/kotlin/codegen/PropertyCodegen.java
index fe57bc6e59e..ed31a0ffd9c 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/PropertyCodegen.java
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/PropertyCodegen.java
@@ -59,6 +59,7 @@ import static org.jetbrains.kotlin.codegen.JvmCodegenUtil.isJvmInterface;
 import static org.jetbrains.kotlin.codegen.serialization.JvmSerializationBindings.*;
 import static org.jetbrains.kotlin.resolve.DescriptorUtils.isCompanionObject;
 import static org.jetbrains.kotlin.resolve.DescriptorUtils.isInterface;
+import static org.jetbrains.kotlin.resolve.DescriptorUtils.isInterfaceCompanionObject;
 import static org.jetbrains.kotlin.resolve.jvm.AsmTypes.PROPERTY_METADATA_TYPE;
 import static org.jetbrains.kotlin.resolve.jvm.diagnostics.DiagnosticsPackage.OtherOrigin;
 import static org.jetbrains.org.objectweb.asm.Opcodes.*;
@@ -315,7 +316,9 @@ public class PropertyCodegen {
             else if (hasPublicFieldAnnotation && !isDelegate) {
                 modifiers |= ACC_PUBLIC;
             }
-            else {
+            else if (isInterfaceCompanionObject(propertyDescriptor.getContainingDeclaration())) {
+                modifiers |= ACC_PRIVATE;
+            } else {
                 modifiers |= getVisibilityForSpecialPropertyBackingField(propertyDescriptor, isDelegate);
             }
 
diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt
index 3c9d503f8cb..0404d6cf81a 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt
@@ -66,14 +66,14 @@ public class GenerationState @JvmOverloads constructor(
         public val incrementalCompilationComponents: IncrementalCompilationComponents? = null,
         public val progress: Progress = Progress.DEAF
 ) {
-    public interface GenerateClassFilter {
-        public fun shouldAnnotateClass(classOrObject: JetClassOrObject): Boolean
-        public fun shouldGenerateClass(classOrObject: JetClassOrObject): Boolean
-        public fun shouldGeneratePackagePart(jetFile: JetFile): Boolean
-        public fun shouldGenerateScript(script: JetScript): Boolean
+    public abstract class GenerateClassFilter {
+        public abstract fun shouldAnnotateClass(classOrObject: JetClassOrObject): Boolean
+        public abstract fun shouldGenerateClass(classOrObject: JetClassOrObject): Boolean
+        public abstract fun shouldGeneratePackagePart(jetFile: JetFile): Boolean
+        public abstract fun shouldGenerateScript(script: JetScript): Boolean
 
         companion object {
-            public val GENERATE_ALL: GenerateClassFilter = object : GenerateClassFilter {
+            public val GENERATE_ALL: GenerateClassFilter = object : GenerateClassFilter() {
                 override fun shouldAnnotateClass(classOrObject: JetClassOrObject): Boolean = true
 
                 override fun shouldGenerateClass(classOrObject: JetClassOrObject): Boolean = true
diff --git a/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/TopDownAnalyzerFacadeForJVM.java b/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/TopDownAnalyzerFacadeForJVM.java
index 6a5303d5385..10e215274ce 100644
--- a/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/TopDownAnalyzerFacadeForJVM.java
+++ b/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/TopDownAnalyzerFacadeForJVM.java
@@ -97,7 +97,7 @@ public enum TopDownAnalyzerFacadeForJVM {
                 new FileBasedDeclarationProviderFactory(moduleContext.getStorageManager(), allFiles);
 
         LookupTracker lookupTracker =
-                incrementalCompilationComponents != null ? incrementalCompilationComponents.getLookupTracker() : LookupTracker.DO_NOTHING;
+                incrementalCompilationComponents != null ? incrementalCompilationComponents.getLookupTracker() : LookupTracker.Companion.getDO_NOTHING();
 
         List<TargetId> targetIds = null;
         if (modules != null) {
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingContext.java b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingContext.java
index 852336feb28..d9e674578aa 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingContext.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingContext.java
@@ -54,7 +54,7 @@ public interface BindingContext {
         @NotNull
         @Override
         public Diagnostics getDiagnostics() {
-            return Diagnostics.EMPTY;
+            return Diagnostics.Companion.getEMPTY();
         }
 
         @Override
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingTraceContext.java b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingTraceContext.java
index 37b58fd8868..dff0a3aa78d 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingTraceContext.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BindingTraceContext.java
@@ -85,7 +85,7 @@ public class BindingTraceContext implements BindingTrace {
 
     private BindingTraceContext(@NotNull MutableSlicedMap map) {
         this.map = map;
-        this.mutableDiagnostics = new MutableDiagnosticsWithSuppression(bindingContext, Diagnostics.EMPTY);
+        this.mutableDiagnostics = new MutableDiagnosticsWithSuppression(bindingContext, Diagnostics.Companion.getEMPTY());
     }
 
     @TestOnly
diff --git a/compiler/testData/asJava/lightClasses/nullabilityAnnotations/TraitClassObjectField.java b/compiler/testData/asJava/lightClasses/nullabilityAnnotations/TraitClassObjectField.java
index 5302cf17afd..b8986f8bd2d 100644
--- a/compiler/testData/asJava/lightClasses/nullabilityAnnotations/TraitClassObjectField.java
+++ b/compiler/testData/asJava/lightClasses/nullabilityAnnotations/TraitClassObjectField.java
@@ -8,6 +8,9 @@ public interface TraitClassObjectField {
         private final java.lang.String x = "";
         private final java.lang.String y = "";
 
+        /**
+         * @deprecated
+         */
         @org.jetbrains.annotations.Nullable
         public final java.lang.String getX() { /* compiled code */ }
 
diff --git a/compiler/testData/asJava/lightClasses/nullabilityAnnotations/TraitClassObjectField.kt b/compiler/testData/asJava/lightClasses/nullabilityAnnotations/TraitClassObjectField.kt
index 18550ad7fc4..e0077c4d43a 100644
--- a/compiler/testData/asJava/lightClasses/nullabilityAnnotations/TraitClassObjectField.kt
+++ b/compiler/testData/asJava/lightClasses/nullabilityAnnotations/TraitClassObjectField.kt
@@ -2,7 +2,7 @@
 
 interface TraitClassObjectField {
     companion object {
-        val x: String? = ""
+        const val x: String? = ""
         private val y: String? = ""
     }
 }
\ No newline at end of file
diff --git a/compiler/testData/codegen/boxWithJava/properties/classObjectProperties/classObjectProperties.kt b/compiler/testData/codegen/boxWithJava/properties/classObjectProperties/classObjectProperties.kt
index 2fdf1ded64c..e683f86290d 100644
--- a/compiler/testData/codegen/boxWithJava/properties/classObjectProperties/classObjectProperties.kt
+++ b/compiler/testData/codegen/boxWithJava/properties/classObjectProperties/classObjectProperties.kt
@@ -6,14 +6,14 @@ class Klass {
 
 interface Trait {
     companion object {
-        val NAME = "Trait"
+        const val NAME = "Trait"
     }
 }
 
 enum class Enoom {
     ;
     companion object {
-        val NAME = "Enoom"
+        const val NAME = "Enoom"
     }
 }
 
diff --git a/compiler/testData/codegen/boxWithStdlib/reflection/genericSignature/kt5112.kt b/compiler/testData/codegen/boxWithStdlib/reflection/genericSignature/kt5112.kt
index c1a8e0d47f4..440078b1541 100644
--- a/compiler/testData/codegen/boxWithStdlib/reflection/genericSignature/kt5112.kt
+++ b/compiler/testData/codegen/boxWithStdlib/reflection/genericSignature/kt5112.kt
@@ -17,9 +17,6 @@ public class ErrorsJvmClass {
 }
 
 fun box(): String {
-    val genericTypeInTrait = javaClass<ErrorsJvmTrait>().getField("param").getGenericType()
-    if (genericTypeInTrait.toString() != "test.G<java.lang.String>") return "fail1: $genericTypeInTrait"
-
     val genericTypeInClassObject = ErrorsJvmTrait.javaClass.getDeclaredField("param").getGenericType()
     if (genericTypeInClassObject.toString() != "test.G<java.lang.String>") return "fail1: $genericTypeInClassObject"
 
diff --git a/compiler/testData/compileJavaAgainstKotlin/staticFields/AnnotationTrait.kt b/compiler/testData/compileJavaAgainstKotlin/staticFields/AnnotationTrait.kt
index 06aed71a05a..a0791b008f4 100644
--- a/compiler/testData/compileJavaAgainstKotlin/staticFields/AnnotationTrait.kt
+++ b/compiler/testData/compileJavaAgainstKotlin/staticFields/AnnotationTrait.kt
@@ -11,13 +11,13 @@ annotation class AFloat(val value: Float)
 interface Test {
 
     companion object {
-        val vstring: String = "Test"
-        val vchar: Char = 'c'
-        val vint: Int = 10
-        val vbyte: Byte = 11
-        val vlong: Long = 12
-        val vdouble: Double = 1.2
-        val vfloat: Float = 1.3.toFloat()
+        const val vstring: String = "Test"
+        const val vchar: Char = 'c'
+        const val vint: Int = 10
+        const val vbyte: Byte = 11
+        const val vlong: Long = 12
+        const val vdouble: Double = 1.2
+        const val vfloat: Float = 1.3.toFloat()
     }
 
 }
\ No newline at end of file
diff --git a/compiler/testData/compileJavaAgainstKotlin/staticFields/AnnotationTrait.txt b/compiler/testData/compileJavaAgainstKotlin/staticFields/AnnotationTrait.txt
index 7f37b1d1dee..78d944d5233 100644
--- a/compiler/testData/compileJavaAgainstKotlin/staticFields/AnnotationTrait.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/staticFields/AnnotationTrait.txt
@@ -43,12 +43,12 @@ public interface Test {
 
     public companion object Companion {
         private constructor Companion()
-        public final val vbyte: kotlin.Byte
-        public final val vchar: kotlin.Char
-        public final val vdouble: kotlin.Double
-        public final val vfloat: kotlin.Float
-        public final val vint: kotlin.Int
-        public final val vlong: kotlin.Long
-        public final val vstring: kotlin.String
+        public const final val vbyte: kotlin.Byte
+        public const final val vchar: kotlin.Char
+        public const final val vdouble: kotlin.Double
+        public const final val vfloat: kotlin.Float
+        public const final val vint: kotlin.Int
+        public const final val vlong: kotlin.Long
+        public const final val vstring: kotlin.String
     }
 }
diff --git a/compiler/testData/compileJavaAgainstKotlin/staticFields/staticTraitProperty.kt b/compiler/testData/compileJavaAgainstKotlin/staticFields/staticTraitProperty.kt
index b1958bb1156..870d34e4b2c 100644
--- a/compiler/testData/compileJavaAgainstKotlin/staticFields/staticTraitProperty.kt
+++ b/compiler/testData/compileJavaAgainstKotlin/staticFields/staticTraitProperty.kt
@@ -3,7 +3,7 @@ package test
 interface Test {
 
   companion object {
-    public val valProp: Int = 10
+    public const val valProp: Int = 10
   }
 
 }
\ No newline at end of file
diff --git a/compiler/testData/compileJavaAgainstKotlin/staticFields/staticTraitProperty.txt b/compiler/testData/compileJavaAgainstKotlin/staticFields/staticTraitProperty.txt
index 0c4db1cd21a..011da1bc2ea 100644
--- a/compiler/testData/compileJavaAgainstKotlin/staticFields/staticTraitProperty.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/staticFields/staticTraitProperty.txt
@@ -4,7 +4,7 @@ public interface Test {
 
     public companion object Companion {
         private constructor Companion()
-        public final val valProp: kotlin.Int
+        public const final val valProp: kotlin.Int
     }
 }
 
diff --git a/compiler/testData/writeFlags/property/classObject/trait/internalConstVal.kt b/compiler/testData/writeFlags/property/classObject/trait/internalConstVal.kt
new file mode 100644
index 00000000000..def3d7a4e07
--- /dev/null
+++ b/compiler/testData/writeFlags/property/classObject/trait/internalConstVal.kt
@@ -0,0 +1,13 @@
+interface Test {
+  companion object {
+    internal const val prop: Int = 0;
+  }
+}
+
+// TESTED_OBJECT_KIND: property
+// TESTED_OBJECTS: Test, prop
+// ABSENT: TRUE
+
+// TESTED_OBJECT_KIND: property
+// TESTED_OBJECTS: Test$Companion, prop
+// FLAGS: ACC_PUBLIC, ACC_FINAL, ACC_STATIC, ACC_SYNTHETIC
\ No newline at end of file
diff --git a/compiler/testData/writeFlags/property/classObject/trait/internalVal.kt b/compiler/testData/writeFlags/property/classObject/trait/internalVal.kt
index 582d52688c7..282113c2293 100644
--- a/compiler/testData/writeFlags/property/classObject/trait/internalVal.kt
+++ b/compiler/testData/writeFlags/property/classObject/trait/internalVal.kt
@@ -1,13 +1,13 @@
 interface Test {
   companion object {
-    val prop: Int = 0;
+    internal val prop: Int = 0;
   }
 }
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test, prop
-// FLAGS: ACC_STATIC, ACC_PUBLIC, ACC_FINAL
+// ABSENT: TRUE
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test$Companion, prop
-// FLAGS: ACC_PRIVATE, ACC_FINAL, ACC_STATIC
\ No newline at end of file
+// FLAGS: ACC_PRIVATE, ACC_FINAL, ACC_STATIC, ACC_SYNTHETIC
\ No newline at end of file
diff --git a/compiler/testData/writeFlags/property/classObject/trait/internalVar.kt b/compiler/testData/writeFlags/property/classObject/trait/internalVar.kt
index e75fc3a8520..15570713906 100644
--- a/compiler/testData/writeFlags/property/classObject/trait/internalVar.kt
+++ b/compiler/testData/writeFlags/property/classObject/trait/internalVar.kt
@@ -1,6 +1,6 @@
 interface Test {
   companion object {
-    var prop: Int = 0;
+    internal var prop: Int = 0;
   }
 }
 
@@ -10,4 +10,4 @@ interface Test {
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test$Companion, prop
-// FLAGS: ACC_PRIVATE, ACC_STATIC
+// FLAGS: ACC_PRIVATE, ACC_STATIC, ACC_SYNTHETIC
diff --git a/compiler/testData/writeFlags/property/classObject/trait/internalVarPrivateSet.kt b/compiler/testData/writeFlags/property/classObject/trait/internalVarPrivateSet.kt
index a40dfe660bc..aded35e1d0e 100644
--- a/compiler/testData/writeFlags/property/classObject/trait/internalVarPrivateSet.kt
+++ b/compiler/testData/writeFlags/property/classObject/trait/internalVarPrivateSet.kt
@@ -1,6 +1,6 @@
 interface Test {
   companion object {
-    var prop: Int = 0
+    internal var prop: Int = 0
       private set
   }
 }
@@ -11,4 +11,4 @@ interface Test {
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test$Companion, prop
-// FLAGS: ACC_PRIVATE, ACC_STATIC
\ No newline at end of file
+// FLAGS: ACC_PRIVATE, ACC_STATIC, ACC_SYNTHETIC
\ No newline at end of file
diff --git a/compiler/testData/writeFlags/property/classObject/trait/publicConstVal.kt b/compiler/testData/writeFlags/property/classObject/trait/publicConstVal.kt
new file mode 100644
index 00000000000..8ec4a97d406
--- /dev/null
+++ b/compiler/testData/writeFlags/property/classObject/trait/publicConstVal.kt
@@ -0,0 +1,13 @@
+interface Test {
+  companion object {
+    public const val prop: Int = 0;
+  }
+}
+
+// TESTED_OBJECT_KIND: property
+// TESTED_OBJECTS: Test, prop
+// FLAGS: ACC_STATIC, ACC_PUBLIC, ACC_FINAL
+
+// TESTED_OBJECT_KIND: property
+// TESTED_OBJECTS: Test$Companion, prop
+// FLAGS: ACC_PUBLIC, ACC_FINAL, ACC_STATIC
\ No newline at end of file
diff --git a/compiler/testData/writeFlags/property/classObject/trait/publicVal.kt b/compiler/testData/writeFlags/property/classObject/trait/publicVal.kt
index f39d344eb04..f87cadd1322 100644
--- a/compiler/testData/writeFlags/property/classObject/trait/publicVal.kt
+++ b/compiler/testData/writeFlags/property/classObject/trait/publicVal.kt
@@ -6,7 +6,7 @@ interface Test {
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test, prop
-// FLAGS: ACC_STATIC, ACC_PUBLIC, ACC_FINAL
+// ABSENT: TRUE
 
 // TESTED_OBJECT_KIND: property
 // TESTED_OBJECTS: Test$Companion, prop
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.java b/compiler/tests/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.java
index 085a7103a95..35c76e65597 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.java
@@ -72,8 +72,8 @@ public abstract class BaseDiagnosticsTest extends
     public static final String CHECK_TYPE_IMPORT = "import " + CHECK_TYPE_PACKAGE + ".*";
 
     public static final String EXPLICIT_FLEXIBLE_TYPES_DIRECTIVE = "EXPLICIT_FLEXIBLE_TYPES";
-    public static final String EXPLICIT_FLEXIBLE_PACKAGE = Flexibility.FLEXIBLE_TYPE_CLASSIFIER.getPackageFqName().asString();
-    public static final String EXPLICIT_FLEXIBLE_CLASS_NAME = Flexibility.FLEXIBLE_TYPE_CLASSIFIER.getRelativeClassName().asString();
+    public static final String EXPLICIT_FLEXIBLE_PACKAGE = Flexibility.Companion.getFLEXIBLE_TYPE_CLASSIFIER().getPackageFqName().asString();
+    public static final String EXPLICIT_FLEXIBLE_CLASS_NAME = Flexibility.Companion.getFLEXIBLE_TYPE_CLASSIFIER().getRelativeClassName().asString();
     private static final String EXPLICIT_FLEXIBLE_TYPES_DECLARATIONS
             = "\npackage " + EXPLICIT_FLEXIBLE_PACKAGE +
               "\npublic class " + EXPLICIT_FLEXIBLE_CLASS_NAME + "<L, U>";
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/GenerationUtils.java b/compiler/tests/org/jetbrains/kotlin/codegen/GenerationUtils.java
index 8e490b59c04..18c69cee7c1 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/GenerationUtils.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/GenerationUtils.java
@@ -54,7 +54,7 @@ public class GenerationUtils {
 
     @NotNull
     public static GenerationState compileManyFilesGetGenerationStateForTest(@NotNull Project project, @NotNull List<JetFile> files) {
-        return compileManyFilesGetGenerationStateForTest(project, files, PackagePartProvider.EMPTY);
+        return compileManyFilesGetGenerationStateForTest(project, files, PackagePartProvider.Companion.getEMPTY());
     }
 
     @NotNull
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/flags/WriteFlagsTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/flags/WriteFlagsTestGenerated.java
index 328743b172e..0db8ae31bd9 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/flags/WriteFlagsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/flags/WriteFlagsTestGenerated.java
@@ -779,6 +779,12 @@ public class WriteFlagsTestGenerated extends AbstractWriteFlagsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("internalConstVal.kt")
+                public void testInternalConstVal() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("compiler/testData/writeFlags/property/classObject/trait/internalConstVal.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("internalVal.kt")
                 public void testInternalVal() throws Exception {
                     String fileName = JetTestUtils.navigationMetadata("compiler/testData/writeFlags/property/classObject/trait/internalVal.kt");
@@ -827,6 +833,12 @@ public class WriteFlagsTestGenerated extends AbstractWriteFlagsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("publicConstVal.kt")
+                public void testPublicConstVal() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("compiler/testData/writeFlags/property/classObject/trait/publicConstVal.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("publicVal.kt")
                 public void testPublicVal() throws Exception {
                     String fileName = JetTestUtils.navigationMetadata("compiler/testData/writeFlags/property/classObject/trait/publicVal.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/resolve/lazy/JvmResolveUtil.java b/compiler/tests/org/jetbrains/kotlin/resolve/lazy/JvmResolveUtil.java
index 48a22cdd70c..abdc0f147a4 100644
--- a/compiler/tests/org/jetbrains/kotlin/resolve/lazy/JvmResolveUtil.java
+++ b/compiler/tests/org/jetbrains/kotlin/resolve/lazy/JvmResolveUtil.java
@@ -37,7 +37,7 @@ public class JvmResolveUtil {
     public static String TEST_MODULE_NAME = "java-integration-test";
     @NotNull
     public static AnalysisResult analyzeOneFileWithJavaIntegrationAndCheckForErrors(@NotNull JetFile file) {
-        return analyzeOneFileWithJavaIntegrationAndCheckForErrors(file, PackagePartProvider.EMPTY);
+        return analyzeOneFileWithJavaIntegrationAndCheckForErrors(file, PackagePartProvider.Companion.getEMPTY());
     }
 
     @NotNull
@@ -63,7 +63,7 @@ public class JvmResolveUtil {
 
     @NotNull
     public static AnalysisResult analyzeOneFileWithJavaIntegration(@NotNull JetFile file) {
-        return analyzeOneFileWithJavaIntegration(file, PackagePartProvider.EMPTY);
+        return analyzeOneFileWithJavaIntegration(file, PackagePartProvider.Companion.getEMPTY());
     }
 
     @NotNull
@@ -71,7 +71,7 @@ public class JvmResolveUtil {
             @NotNull Project project,
             @NotNull Collection<JetFile> files
     ) {
-        return analyzeFilesWithJavaIntegrationAndCheckForErrors(project, files, PackagePartProvider.EMPTY);
+        return analyzeFilesWithJavaIntegrationAndCheckForErrors(project, files, PackagePartProvider.Companion.getEMPTY());
     }
 
     @NotNull
diff --git a/compiler/tests/org/jetbrains/kotlin/test/JetTestUtils.java b/compiler/tests/org/jetbrains/kotlin/test/JetTestUtils.java
index 96db1c32eb5..ac35a27402b 100644
--- a/compiler/tests/org/jetbrains/kotlin/test/JetTestUtils.java
+++ b/compiler/tests/org/jetbrains/kotlin/test/JetTestUtils.java
@@ -125,7 +125,7 @@ public class JetTestUtils {
                 @NotNull
                 @Override
                 public Diagnostics getDiagnostics() {
-                    return Diagnostics.EMPTY;
+                    return Diagnostics.Companion.getEMPTY();
                 }
 
                 @Override
diff --git a/core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRenderer.kt b/core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRenderer.kt
index 6862ff181a7..ef154732dfb 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRenderer.kt
+++ b/core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRenderer.kt
@@ -26,36 +26,36 @@ import org.jetbrains.kotlin.types.JetType
 import org.jetbrains.kotlin.types.TypeConstructor
 import org.jetbrains.kotlin.types.TypeProjection
 
-public interface DescriptorRenderer : Renderer<DeclarationDescriptor> {
+public abstract class DescriptorRenderer : Renderer<DeclarationDescriptor> {
     public fun withOptions(changeOptions: DescriptorRendererOptions.() -> Unit): DescriptorRenderer {
         val options = (this as DescriptorRendererImpl).options.copy()
         options.changeOptions()
         options.lock()
         return DescriptorRendererImpl(options)
     }
-    
-    public fun renderType(type: JetType): String
 
-    public fun renderTypeArguments(typeArguments: List<TypeProjection>): String
+    public abstract fun renderType(type: JetType): String
 
-    public fun renderTypeProjection(typeProjection: TypeProjection): String
+    public abstract fun renderTypeArguments(typeArguments: List<TypeProjection>): String
 
-    public fun renderTypeConstructor(typeConstructor: TypeConstructor): String
+    public abstract fun renderTypeProjection(typeProjection: TypeProjection): String
 
-    public fun renderClassifierName(klass: ClassifierDescriptor): String
+    public abstract fun renderTypeConstructor(typeConstructor: TypeConstructor): String
 
-    public fun renderAnnotation(annotation: AnnotationDescriptor, target: AnnotationUseSiteTarget? = null): String
+    public abstract fun renderClassifierName(klass: ClassifierDescriptor): String
 
-    override fun render(declarationDescriptor: DeclarationDescriptor): String
+    public abstract fun renderAnnotation(annotation: AnnotationDescriptor, target: AnnotationUseSiteTarget? = null): String
 
-    public fun renderValueParameters(parameters: Collection<ValueParameterDescriptor>, synthesizedParameterNames: Boolean): String
+    override abstract fun render(declarationDescriptor: DeclarationDescriptor): String
+
+    public abstract fun renderValueParameters(parameters: Collection<ValueParameterDescriptor>, synthesizedParameterNames: Boolean): String
 
     public fun renderFunctionParameters(functionDescriptor: FunctionDescriptor): String
             = renderValueParameters(functionDescriptor.valueParameters, functionDescriptor.hasSynthesizedParameterNames())
 
-    public fun renderName(name: Name): String
+    public abstract fun renderName(name: Name): String
 
-    public fun renderFqName(fqName: FqNameBase): String
+    public abstract fun renderFqName(fqName: FqNameBase): String
 
     public interface ValueParametersHandler {
         public fun appendBeforeValueParameters(parameterCount: Int, builder: StringBuilder)
diff --git a/core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt b/core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt
index 727b5256a70..9b5d480cb72 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt
+++ b/core/descriptors/src/org/jetbrains/kotlin/renderer/DescriptorRendererImpl.kt
@@ -40,7 +40,7 @@ import java.util.*
 
 internal class DescriptorRendererImpl(
         val options: DescriptorRendererOptionsImpl
-) : DescriptorRenderer, DescriptorRendererOptions by options/* this gives access to options without qualifier */ {
+) : DescriptorRenderer(), DescriptorRendererOptions by options/* this gives access to options without qualifier */ {
 
     init {
         assert(options.isLocked)
diff --git a/core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java b/core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java
index fab362487d9..6d4037bd760 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java
+++ b/core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java
@@ -306,7 +306,7 @@ public class DescriptorUtils {
     }
 
     public static boolean isInterfaceCompanionObject(@NotNull DeclarationDescriptor descriptor) {
-        return isCompanionObject(descriptor) && isKindOf(descriptor.getContainingDeclaration(), ClassKind.INTERFACE);
+        return isCompanionObject(descriptor) && isInterface(descriptor.getContainingDeclaration());
     }
 
     public static boolean isObject(@NotNull DeclarationDescriptor descriptor) {
diff --git a/idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluationBuilder.kt b/idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluationBuilder.kt
index e78517a9fd4..620fe5eb8d1 100644
--- a/idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluationBuilder.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluationBuilder.kt
@@ -352,7 +352,7 @@ class KotlinEvaluator(val codeFragment: JetCodeFragment,
 
                 val (bindingContext, moduleDescriptor, files) = jetFile.checkForErrors(true)
 
-                val generateClassFilter = object : GenerationState.GenerateClassFilter {
+                val generateClassFilter = object : GenerationState.GenerateClassFilter() {
                     override fun shouldGeneratePackagePart(file: JetFile) = file == jetFile
                     override fun shouldAnnotateClass(classOrObject: JetClassOrObject) = true
                     override fun shouldGenerateClass(classOrObject: JetClassOrObject) = classOrObject.getContainingJetFile() == jetFile
diff --git a/idea/src/org/jetbrains/kotlin/idea/liveTemplates/macro/JetAnonymousSuperMacro.java b/idea/src/org/jetbrains/kotlin/idea/liveTemplates/macro/JetAnonymousSuperMacro.java
index 2c913a9e16b..734b9a5f06d 100644
--- a/idea/src/org/jetbrains/kotlin/idea/liveTemplates/macro/JetAnonymousSuperMacro.java
+++ b/idea/src/org/jetbrains/kotlin/idea/liveTemplates/macro/JetAnonymousSuperMacro.java
@@ -102,7 +102,7 @@ public class JetAnonymousSuperMacro extends Macro {
 
         List<PsiNamedElement> result = new ArrayList<PsiNamedElement>();
 
-        for (DeclarationDescriptor descriptor : scope.getDescriptors(DescriptorKindFilter.NON_SINGLETON_CLASSIFIERS, JetScope.ALL_NAME_FILTER)) {
+        for (DeclarationDescriptor descriptor : scope.getDescriptors(DescriptorKindFilter.NON_SINGLETON_CLASSIFIERS, JetScope.Companion.getALL_NAME_FILTER())) {
             if (!(descriptor instanceof ClassDescriptor)) continue;
             ClassDescriptor classDescriptor = (ClassDescriptor) descriptor;
             if (!classDescriptor.getModality().isOverridable()) continue;
diff --git a/idea/testData/findUsages/kotlin/findPropertyUsages/kotlinClassObjectPropertyUsage.0.kt b/idea/testData/findUsages/kotlin/findPropertyUsages/kotlinClassObjectPropertyUsage.0.kt
index 15a2aee3f37..3b367f90916 100644
--- a/idea/testData/findUsages/kotlin/findPropertyUsages/kotlinClassObjectPropertyUsage.0.kt
+++ b/idea/testData/findUsages/kotlin/findPropertyUsages/kotlinClassObjectPropertyUsage.0.kt
@@ -4,7 +4,7 @@ package server
 
 interface Some {
     companion object {
-        val <caret>XX = 1
+        const val <caret>XX = 1
     }
 }
 
diff --git a/idea/testData/resolve/referenceInJava/dependencies.kt b/idea/testData/resolve/referenceInJava/dependencies.kt
index 3e86151f951..999db0d9b7f 100644
--- a/idea/testData/resolve/referenceInJava/dependencies.kt
+++ b/idea/testData/resolve/referenceInJava/dependencies.kt
@@ -27,7 +27,7 @@ public object KotlinObject {
 
 public interface StaticFieldInClassObjectInTrait {
     companion object {
-        public val XX: String = "xx"
+        public const val XX: String = "xx"
     }
 }
 
diff --git a/jps-plugin/testData/incremental/pureKotlin/traitClassObjectConstantChanged/const.kt b/jps-plugin/testData/incremental/pureKotlin/traitClassObjectConstantChanged/const.kt
index 6d7566e3856..0fe79d3540c 100644
--- a/jps-plugin/testData/incremental/pureKotlin/traitClassObjectConstantChanged/const.kt
+++ b/jps-plugin/testData/incremental/pureKotlin/traitClassObjectConstantChanged/const.kt
@@ -3,6 +3,6 @@ package test
 interface Trait {
     companion object {
         // Old and new constant values are different, but their hashes are the same
-        val CONST = "BF"
+        const val CONST = "BF"
     }
 }