diff --git a/core/descriptors/src/org/jetbrains/kotlin/types/ErrorType.kt b/core/descriptors/src/org/jetbrains/kotlin/types/ErrorType.kt
new file mode 100644
index 00000000000..3aa8ecbea74
--- /dev/null
+++ b/core/descriptors/src/org/jetbrains/kotlin/types/ErrorType.kt
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.types
+
+import org.jetbrains.kotlin.descriptors.annotations.Annotations
+import org.jetbrains.kotlin.resolve.scopes.MemberScope
+
+class ErrorType @JvmOverloads internal constructor(
+        override val constructor: TypeConstructor,
+        override val memberScope: MemberScope,
+        override val arguments: List<TypeProjection> = emptyList(),
+        override val isMarkedNullable: Boolean = false
+) : SimpleType() {
+    override val annotations: Annotations
+        get() = Annotations.EMPTY
+
+    override fun toString(): String =
+            constructor.toString() + if (arguments.isEmpty()) "" else arguments.joinToString(", ", "<", ">", -1, "...", null)
+
+    override fun replaceAnnotations(newAnnotations: Annotations): SimpleType = this
+
+    override fun makeNullableAsSpecified(newNullability: Boolean): SimpleType =
+            ErrorType(constructor, memberScope, arguments, newNullability)
+}
diff --git a/core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java b/core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java
index 2884cce37f3..e69b38bcf43 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java
+++ b/core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java
@@ -43,7 +43,6 @@ import java.util.Set;
 
 import static java.util.Collections.emptySet;
 import static kotlin.collections.CollectionsKt.emptyList;
-import static kotlin.collections.CollectionsKt.joinToString;
 
 public class ErrorUtils {
     private static final ModuleDescriptor ERROR_MODULE;
@@ -296,7 +295,7 @@ public class ErrorUtils {
                                         Visibilities.INTERNAL);
             MemberScope memberScope = createErrorScope(getName().asString());
             errorConstructor.setReturnType(
-                    new ErrorTypeImpl(
+                    new ErrorType(
                             createErrorTypeConstructorWithCustomDebugName("<ERROR>", this),
                             memberScope
                     )
@@ -404,12 +403,12 @@ public class ErrorUtils {
 
     @NotNull
     public static SimpleType createErrorTypeWithCustomConstructor(@NotNull String debugName, @NotNull TypeConstructor typeConstructor) {
-        return new ErrorTypeImpl(typeConstructor, createErrorScope(debugName));
+        return new ErrorType(typeConstructor, createErrorScope(debugName));
     }
 
     @NotNull
     public static SimpleType createErrorTypeWithArguments(@NotNull String debugMessage, @NotNull List<TypeProjection> arguments) {
-        return new ErrorTypeImpl(createErrorTypeConstructor(debugMessage), createErrorScope(debugMessage), arguments, false);
+        return new ErrorType(createErrorTypeConstructor(debugMessage), createErrorScope(debugMessage), arguments, false);
     }
 
     @NotNull
@@ -486,76 +485,6 @@ public class ErrorUtils {
         return candidate instanceof ErrorClassDescriptor;
     }
 
-    public static class ErrorTypeImpl extends SimpleType {
-        private final TypeConstructor constructor;
-        private final MemberScope memberScope;
-        private final List<TypeProjection> arguments;
-        private final boolean nullability;
-
-        private ErrorTypeImpl(
-                @NotNull TypeConstructor constructor,
-                @NotNull MemberScope memberScope,
-                @NotNull List<TypeProjection> arguments,
-                boolean nullability
-        ) {
-            this.constructor = constructor;
-            this.memberScope = memberScope;
-            this.arguments = arguments;
-            this.nullability = nullability;
-        }
-
-        private ErrorTypeImpl(@NotNull TypeConstructor constructor, @NotNull MemberScope memberScope) {
-            this(constructor, memberScope, Collections.<TypeProjection>emptyList(), false);
-        }
-
-        @NotNull
-        @Override
-        public TypeConstructor getConstructor() {
-            return constructor;
-        }
-
-        @NotNull
-        @Override
-        public List<TypeProjection> getArguments() {
-            return arguments;
-        }
-
-        @Override
-        public boolean isMarkedNullable() {
-            return nullability;
-        }
-
-        @NotNull
-        @Override
-        public MemberScope getMemberScope() {
-            return memberScope;
-        }
-
-        @NotNull
-        @Override
-        public Annotations getAnnotations() {
-            return Annotations.Companion.getEMPTY();
-        }
-
-        @NotNull
-        @Override
-        public String toString() {
-            return constructor.toString() + (arguments.isEmpty() ? "" : joinToString(arguments, ", ", "<", ">", -1, "...", null));
-        }
-
-        @NotNull
-        @Override
-        public SimpleType replaceAnnotations(@NotNull Annotations newAnnotations) {
-            return this;
-        }
-
-        @NotNull
-        @Override
-        public SimpleType makeNullableAsSpecified(boolean newNullability) {
-            return new ErrorTypeImpl(constructor, memberScope, arguments, newNullability);
-        }
-    }
-
     @NotNull
     public static ModuleDescriptor getErrorModule() {
         return ERROR_MODULE;
diff --git a/core/descriptors/src/org/jetbrains/kotlin/types/KotlinType.kt b/core/descriptors/src/org/jetbrains/kotlin/types/KotlinType.kt
index 80c24760e2a..3e3b1ebaddb 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/types/KotlinType.kt
+++ b/core/descriptors/src/org/jetbrains/kotlin/types/KotlinType.kt
@@ -159,8 +159,7 @@ abstract class FlexibleType(val lowerBound: SimpleType, val upperBound: SimpleTy
 }
 
 val KotlinType.isError: Boolean
-    get() {
-        val unwrapped = unwrap()
-        return unwrapped is ErrorUtils.ErrorTypeImpl ||
-               (unwrapped is FlexibleType && unwrapped.delegate is ErrorUtils.ErrorTypeImpl)
+    get() = unwrap().let { unwrapped ->
+        unwrapped is ErrorType ||
+        (unwrapped is FlexibleType && unwrapped.delegate is ErrorType)
     }