Author: Julia Lawall <julia@diku.dk> bp was tested for NULL a few lines before, followed by a return, and there is no intervening modification of its value. A simplified version of the semantic match that finds this problem is as follows: (http://www.emn.fr/x-info/coccinelle/) // @r exists@ local idexpression x; expression E; position p1,p2; @@ if (x == …