diff --git a/platform/core-impl/src/com/intellij/psi/impl/source/tree/AstBufferUtil.java b/platform/core-impl/src/com/intellij/psi/impl/source/tree/AstBufferUtil.java
index be63ee01c622..ae336214a3e9 100644
--- a/platform/core-impl/src/com/intellij/psi/impl/source/tree/AstBufferUtil.java
+++ b/platform/core-impl/src/com/intellij/psi/impl/source/tree/AstBufferUtil.java
@@ -103,7 +103,6 @@ public class AstBufferUtil {
     public void visitComposite(CompositeElement composite) {
       if (composite instanceof LazyParseableElement) {
         LazyParseableElement lpe = (LazyParseableElement)composite;
-        assert buffer != null;
         int lpeResult = lpe.copyTo(buffer, end);
         if (lpeResult >= 0) {
           end = lpeResult;
diff --git a/platform/core-impl/src/com/intellij/psi/impl/source/tree/LazyParseableElement.java b/platform/core-impl/src/com/intellij/psi/impl/source/tree/LazyParseableElement.java
index c259563ae638..d1edc6fb2dba 100644
--- a/platform/core-impl/src/com/intellij/psi/impl/source/tree/LazyParseableElement.java
+++ b/platform/core-impl/src/com/intellij/psi/impl/source/tree/LazyParseableElement.java
@@ -28,6 +28,7 @@ import com.intellij.psi.tree.ILazyParseableElementType;
 import com.intellij.util.text.CharArrayUtil;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.TestOnly;
 
 public class LazyParseableElement extends CompositeElement {
@@ -215,7 +216,7 @@ public class LazyParseableElement extends CompositeElement {
     return super.getLastChildNode();
   }
 
-  public int copyTo(char[] buffer, int start) {
+  public int copyTo(@Nullable char[] buffer, int start) {
     CharSequence text = myText();
     if (text == null) return -1;