diff --git a/src/main/php/lang/ast/CompilingClassloader.class.php b/src/main/php/lang/ast/CompilingClassloader.class.php
index 118eaf5e..b3fef4a5 100755
--- a/src/main/php/lang/ast/CompilingClassloader.class.php
+++ b/src/main/php/lang/ast/CompilingClassloader.class.php
@@ -53,6 +53,7 @@ protected function locateSource($class) {
   public function providesUri($uri) {
     if (isset($this->source[$uri])) return true;
     if (0 !== substr_compare($uri, self::EXTENSION, -4)) return false;
+    if (0 === substr_compare($uri, \xp::CLASS_FILE_EXT, -strlen(\xp::CLASS_FILE_EXT))) return false;
 
     foreach (ClassLoader::getDefault()->getLoaders() as $loader) {
       if ($loader instanceof self) continue;