In the following example, the address of structure member foo.b is being cast as a struct pointer and then assigned to f2. With lint -Xalias_level=weak (or higher), this example generates an error.
struct foo{ int a; int b; }; struct foo *f1; struct foo *f2; void main() { f2 = (struct foo *)&f1->b; /* cast of a scalar pointer to struct pointer error*/ }