added an error check.

git-svn-id: http://anonsvn.jboss.org/repos/javassist/trunk@93 30ef5769-5b8d-40dd-aea6-55b5d6557bb3

src/main/javassist/ClassPool.java

@@ -285,6 +285,10 @@ public class ClassPool {
     public Class toClass(CtClass cc)
         throws NotFoundException, CannotCompileException, IOException
     {
+        if (cc.getClassPool() != this)
+           throw new CannotCompileException(
+                 "not contained in this class pool: " + cc.getName());
+
         try {
             if (classLoader == null)
                 classLoader = new SimpleLoader();