more diagnostics for EA-88292

platform/core-api/src/com/intellij/lexer/FlexAdapter.java

@@ -120,4 +120,9 @@ public class FlexAdapter extends LexerBase {
       LOG.warn(myFlex.getClass().getName(), e);
     }
   }
+
+  @Override
+  public String toString() {
+    return "FlexAdapter for " + myFlex.getClass().getName();
+  }
 }

platform/editor-ui-ex/src/com/intellij/openapi/editor/ex/util/LexerEditorHighlighter.java

@@ -15,6 +15,7 @@
  */
 package com.intellij.openapi.editor.ex.util;
 
+import com.intellij.lexer.FlexAdapter;
 import com.intellij.lexer.Lexer;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.diagnostic.Logger;
@@ -437,7 +438,9 @@ public class LexerEditorHighlighter implements EditorHighlighter, PrioritizedDoc
 
   @Override
   public String toString() {
-    return getClass().getName() + "(" + myLexer.getClass().getName() + "): '" + myLexer.getBufferSequence()+"'" ;
+    return getClass().getName() + "(" +
+           (myLexer.getClass() == FlexAdapter.class ? myLexer.toString() : myLexer.getClass().getName()) +
+           "): '" + myLexer.getBufferSequence() + "'";
   }
 
   public class HighlighterIteratorImpl implements HighlighterIterator {