@@
statement S;
expression V;
@@

V = isc_mem_allocate(...);
- if (V == NULL) S

@@
type T;
statement S;
expression V;
@@

V = (T *)isc_mem_allocate(...);
- if (V == NULL) S

@@
statement S;
expression V;
@@

if (V == NULL) V = isc_mem_allocate(...);
- if (V == NULL) S

@@
statement S1, S2;
expression V;
@@

V = isc_mem_allocate(...);
- if (V == NULL) S1 else { S2 }
+ S2

@@
type T;
expression V, E1, E2;
@@

- V = (T)isc_mem_allocate(E1, E2);
+ V = isc_mem_allocate(E1, E2);