added the source for all sandbox security exceptions

src/Node/CheckToStringNode.php

@@ -36,7 +36,7 @@ class CheckToStringNode extends AbstractExpression
         $compiler
             ->raw('$this->sandbox->ensureToStringAllowed(')
             ->subcompile($this->getNode('expr'))
-            ->raw(')')
+            ->raw(', $this->source)')
         ;
     }
 }