not only de-allocate the vector, but also remove it from the list.

This is to prevent a crash when after simulating with a buggy input like:
save all @q1[nonesense] (non-existing parameter) a command 'print all'
is given.

src/frontend/parse.c

@@ -43,7 +43,7 @@ struct pnode *ft_getpnames_from_string(const char *sz, bool check)
      * structure must also be freed if the check fails since it is not
      * being returned. */
     if (check && !checkvalid(pn)) {
-        dvec_free(pn->pn_value);
+        vec_free_x(pn->pn_value);
         free_pnode(pn);
         return (struct pnode *) NULL;
     }