// Copyright: (C) 2009 Gilles Muller, Julia Lawall, INRIA, DIKU.  GPLv2.

@def0@
expression x;
position p0;
@@
x@p0 = add_volume(...)

@protected@
expression def0.x,E;
position def0.p0;
position p;
statement S;
@@
x@p0
... when != x = E
if (!IS_ERR(x) && ...) {<... x@p ...>} else S

@unprotected@
expression def0.x,E;
identifier fld;
position def0.p0;
position p != protected.p;
@@
x@p0
... when != x = E
* x@p->fld