Author: Julia Lawall <julia@diku.dk> In each case, the NULL test is not necessary because the function is static and at the only places where it is called, the us argument has already been dereferenced. The semantic patch that finds the problem is as follows: (http://www.emn.fr/x-info/coccinelle/) // @@ type T; expression E,E1; identifier i,fld; statement S; …