diff --git a/libs/sysplugins/internal.compile_include.php b/libs/sysplugins/internal.compile_include.php
index 586c2c92..52028576 100644
--- a/libs/sysplugins/internal.compile_include.php
+++ b/libs/sysplugins/internal.compile_include.php
@@ -31,8 +31,8 @@ class Smarty_Internal_Compile_Include extends Smarty_Internal_CompileBase {
         $include_file = $_attr['file'];
         $has_compiled_template = false;
         if ($compiler->smarty->merge_compiled_includes) {
-            // check if compiled code can be merged
-            if (strpos($include_file, '$_smarty_tpl') === false) {
+            // check if compiled code can be merged (contains nor variable)
+            if (strpos($include_file, '$_') === false) {
                 eval("\$tmp = $include_file;");
                 $tpl = $compiler->smarty->createTemplate ($tmp, $compiler->template->cache_id, $compiler->template->compile_id, $compiler->template);
                 do {