diff --git a/core/builtins/native/kotlin/Enum.kt b/core/builtins/native/kotlin/Enum.kt
index 7fa7cdd9e5a..5d290eacfd3 100644
--- a/core/builtins/native/kotlin/Enum.kt
+++ b/core/builtins/native/kotlin/Enum.kt
@@ -22,7 +22,7 @@ package kotlin
  * information on enum classes.
  */
 public abstract class Enum<E : Enum<E>>(name: String, ordinal: Int): Comparable<E> {
-    class object {}
+    default object {}
 
     /**
      * Returns the name of this enum constant, exactly as declared in its enum declaration.
diff --git a/core/builtins/native/kotlin/Numbers.kt b/core/builtins/native/kotlin/Numbers.kt
index 9b8a92bb965..5a7dfa8cc24 100644
--- a/core/builtins/native/kotlin/Numbers.kt
+++ b/core/builtins/native/kotlin/Numbers.kt
@@ -23,7 +23,7 @@ package kotlin
  * On the JVM, non-nullable values of this type are represented as values of the primitive type `byte`.
  */
 public class Byte private () : Number, Comparable<Byte> {
-    class object {}
+    default object {}
 
     public override fun compareTo(other: Byte): Int
     public fun compareTo(other: Char): Int
@@ -100,7 +100,7 @@ public class Byte private () : Number, Comparable<Byte> {
  * On the JVM, non-nullable values of this type are represented as values of the primitive type `short`.
  */
 public class Short private () : Number, Comparable<Short> {
-    class object {}
+    default object {}
 
     public fun compareTo(other: Byte): Int
     public fun compareTo(other: Char): Int
@@ -177,7 +177,7 @@ public class Short private () : Number, Comparable<Short> {
  * On the JVM, non-nullable values of this type are represented as values of the primitive type `int`.
  */
 public class Int private () : Number, Comparable<Int> {
-    class object {}
+    default object {}
 
     public fun compareTo(other: Byte): Int
     public fun compareTo(other: Char): Int
@@ -262,7 +262,7 @@ public class Int private () : Number, Comparable<Int> {
  * On the JVM, non-nullable values of this type are represented as values of the primitive type `long`.
  */
 public class Long private () : Number, Comparable<Long> {
-    class object {}
+    default object {}
 
     public fun compareTo(other: Byte): Int
     public fun compareTo(other: Char): Int
@@ -347,7 +347,7 @@ public class Long private () : Number, Comparable<Long> {
  * On the JVM, non-nullable values of this type are represented as values of the primitive type `float`.
  */
 public class Float private () : Number, Comparable<Float> {
-    class object : FloatingPointConstants<Float> {}
+    default object : FloatingPointConstants<Float> {}
 
     public fun compareTo(other: Byte): Int
     public fun compareTo(other: Char): Int
@@ -424,7 +424,7 @@ public class Float private () : Number, Comparable<Float> {
  * On the JVM, non-nullable values of this type are represented as values of the primitive type `double`.
  */
 public class Double private () : Number, Comparable<Double> {
-    class object : FloatingPointConstants<Double> {}
+    default object : FloatingPointConstants<Double> {}
 
     public fun compareTo(other: Byte): Int
     public fun compareTo(other: Char): Int
diff --git a/core/builtins/native/kotlin/String.kt b/core/builtins/native/kotlin/String.kt
index 08fe3c2c6db..c5309bffe4e 100644
--- a/core/builtins/native/kotlin/String.kt
+++ b/core/builtins/native/kotlin/String.kt
@@ -21,7 +21,7 @@ package kotlin
  * implemented as instances of this class.
  */
 public class String : Comparable<String>, CharSequence {
-    class object {}
+    default object {}
     
     /**
      * Returns a string obtained by concatenating this string with the string representation of the given [other] object.
diff --git a/core/builtins/src/kotlin/Ranges.kt b/core/builtins/src/kotlin/Ranges.kt
index 227e856f5c9..2d0506ba49d 100644
--- a/core/builtins/src/kotlin/Ranges.kt
+++ b/core/builtins/src/kotlin/Ranges.kt
@@ -38,7 +38,7 @@ public class ByteRange(override val start: Byte, override val end: Byte) : Range
     override fun hashCode(): Int =
         if (isEmpty()) -1 else (31 * start.toInt() + end)
 
-    class object {
+    default object {
         /** An empty range of values of type Byte. */
         public val EMPTY: ByteRange = ByteRange(1, 0)
     }
@@ -64,7 +64,7 @@ public class CharRange(override val start: Char, override val end: Char) : Range
     override fun hashCode(): Int =
         if (isEmpty()) -1 else (31 * start.toInt() + end)
 
-    class object {
+    default object {
         /** An empty range of values of type Char. */
         public val EMPTY: CharRange = CharRange(1.toChar(), 0.toChar())
     }
@@ -90,7 +90,7 @@ public class ShortRange(override val start: Short, override val end: Short) : Ra
     override fun hashCode(): Int =
         if (isEmpty()) -1 else (31 * start.toInt() + end)
 
-    class object {
+    default object {
         /** An empty range of values of type Short. */
         public val EMPTY: ShortRange = ShortRange(1, 0)
     }
@@ -116,7 +116,7 @@ public class IntRange(override val start: Int, override val end: Int) : Range<In
     override fun hashCode(): Int =
         if (isEmpty()) -1 else (31 * start + end)
 
-    class object {
+    default object {
         /** An empty range of values of type Int. */
         public val EMPTY: IntRange = IntRange(1, 0)
     }
@@ -142,7 +142,7 @@ public class LongRange(override val start: Long, override val end: Long) : Range
     override fun hashCode(): Int =
         if (isEmpty()) -1 else (31 * (start xor (start ushr 32)) + (end xor (end ushr 32))).toInt()
 
-    class object {
+    default object {
         /** An empty range of values of type Long. */
         public val EMPTY: LongRange = LongRange(1, 0)
     }
@@ -168,7 +168,7 @@ public class FloatRange(override val start: Float, override val end: Float) : Ra
     override fun hashCode(): Int =
         if (isEmpty()) -1 else (31 * java.lang.Float.floatToIntBits(start) + java.lang.Float.floatToIntBits(end))
 
-    class object {
+    default object {
         /** An empty range of values of type Float. */
         public val EMPTY: FloatRange = FloatRange(1.0f, 0.0f)
     }
@@ -199,7 +199,7 @@ public class DoubleRange(override val start: Double, override val end: Double) :
         return (31 * result + (temp xor (temp ushr 32))).toInt()
     }
 
-    class object {
+    default object {
         /** An empty range of values of type Double. */
         public val EMPTY: DoubleRange = DoubleRange(1.0, 0.0)
     }
diff --git a/generators/src/org/jetbrains/kotlin/generators/builtins/numbers.kt b/generators/src/org/jetbrains/kotlin/generators/builtins/numbers.kt
index b496cb8d445..c546bfea299 100644
--- a/generators/src/org/jetbrains/kotlin/generators/builtins/numbers.kt
+++ b/generators/src/org/jetbrains/kotlin/generators/builtins/numbers.kt
@@ -42,7 +42,7 @@ class GenerateNumbers(out: PrintWriter) : BuiltInsSourceGenerator(out) {
             generateDoc(kind)
             out.println("public class $className private () : Number, Comparable<$className> {")
 
-            out.print("    class object")
+            out.print("    default object")
             if (kind == PrimitiveType.FLOAT || kind == PrimitiveType.DOUBLE) {
                 out.print(" : FloatingPointConstants<$className>")
             }
diff --git a/generators/src/org/jetbrains/kotlin/generators/builtins/ranges.kt b/generators/src/org/jetbrains/kotlin/generators/builtins/ranges.kt
index 27b4f14a5df..31a98247649 100644
--- a/generators/src/org/jetbrains/kotlin/generators/builtins/ranges.kt
+++ b/generators/src/org/jetbrains/kotlin/generators/builtins/ranges.kt
@@ -82,7 +82,7 @@ public class $range(override val start: $t, override val end: $t) : Range<$t>, P
 
     override fun hashCode(): Int $hashCode
 
-    class object {
+    default object {
         /** An empty range of values of type $t. */
         public val EMPTY: $range = $range($emptyBounds)
     }