diff --git a/platform/core-api/src/com/intellij/psi/tree/CustomParsingType.java b/platform/core-api/src/com/intellij/psi/tree/CustomParsingType.java
index 45fb4110211b..d369c892d2ef 100644
--- a/platform/core-api/src/com/intellij/psi/tree/CustomParsingType.java
+++ b/platform/core-api/src/com/intellij/psi/tree/CustomParsingType.java
@@ -19,17 +19,13 @@
  */
 package com.intellij.psi.tree;
 
-import com.intellij.lang.ASTNode;
 import com.intellij.lang.Language;
-import com.intellij.util.CharTable;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-public abstract class CustomParsingType extends IElementType {
+public abstract class CustomParsingType extends IElementType implements ICustomParsingType {
   public CustomParsingType(@NotNull @NonNls String debugName, @Nullable Language language) {
     super(debugName, language);
   }
-
-  public abstract ASTNode parse(CharSequence text, CharTable table);
 }
diff --git a/platform/core-api/src/com/intellij/psi/tree/ICustomParsingType.java b/platform/core-api/src/com/intellij/psi/tree/ICustomParsingType.java
new file mode 100644
index 000000000000..d37106994c61
--- /dev/null
+++ b/platform/core-api/src/com/intellij/psi/tree/ICustomParsingType.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2000-2016 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 com.intellij.psi.tree;
+
+import com.intellij.lang.ASTNode;
+import com.intellij.util.CharTable;
+
+public interface ICustomParsingType {
+  ASTNode parse(CharSequence text, CharTable table);
+}
diff --git a/platform/core-impl/src/com/intellij/lang/impl/PsiBuilderImpl.java b/platform/core-impl/src/com/intellij/lang/impl/PsiBuilderImpl.java
index a07f110329e3..0563e613ea61 100644
--- a/platform/core-impl/src/com/intellij/lang/impl/PsiBuilderImpl.java
+++ b/platform/core-impl/src/com/intellij/lang/impl/PsiBuilderImpl.java
@@ -1562,7 +1562,7 @@ public class PsiBuilderImpl extends UserDataHolderBase implements PsiBuilder {
         }
 
         if (oldNode.getElementType() instanceof ILazyParseableElementType && type instanceof ILazyParseableElementType ||
-            oldNode.getElementType() instanceof CustomParsingType && type instanceof CustomParsingType) {
+            oldNode.getElementType() instanceof ICustomParsingType && type instanceof ICustomParsingType) {
           return ((TreeElement)oldNode).textMatches(token.getText())
                  ? ThreeState.YES
                  : ThreeState.NO;
@@ -1853,8 +1853,8 @@ public class PsiBuilderImpl extends UserDataHolderBase implements PsiBuilder {
       return new PsiWhiteSpaceImpl(text);
     }
 
-    if (type instanceof CustomParsingType) {
-      return (TreeElement)((CustomParsingType)type).parse(text, myCharTable);
+    if (type instanceof ICustomParsingType) {
+      return (TreeElement)((ICustomParsingType)type).parse(text, myCharTable);
     }
 
     if (type instanceof ILazyParseableElementType) {