Author: Julia Lawall <julia@diku.dk> map_destroy dereferences its argument. The call is furthermore only reachable when this argument is NULL. Thus the call is dropped. The semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @@ expression *x; @@ *if (x == NULL) { … * map_destroy(x); … return …; } // Signed-off-by: Julia …