// find cases where a pointer is dereferenced and then compared to NULL
// this considers a very special case that typically finds dereferences in 
// debugging code
//
// Confidence: High
// Copyright: (C) Gilles Muller, Julia Lawall, EMN, INRIA, DIKU.  GPLv2.
// URL: http://coccinelle.lip6.fr/rules/mini_null_ref3.html
// Options:

@disable is_null@
identifier f;
expression E;
identifier fld;
statement S;
@@

+ if (E == NULL) S
  f(...,E->fld,...);
- if (E == NULL) S

@@
identifier f;
expression E;
identifier fld;
statement S;
@@

+ if (!E) S
  f(...,E->fld,...);
- if (!E) S