C-style cast not converted when result is not assigned to a pointer

[john-h-kastner]

void test() {
  int *a;
  if (a == (int*) 0)
    return;
}

converts to

void test() {
  _Ptr<int> a = ((void *)0);
  if (a == (int*) 0)
    return;
}

The cast (int*) is not converted to (_Ptr<int>), but this is required before the function can be _Checked. This creates a bit more manual work when converting code with 3C.

[john-h-kastner]

The fix: constraints variables for CStyleCastExprs are currently created by ConstraintResolver in getExprConstraintVars, but getExprConstraintVars is only called when we need to get constraint variables for assignment expressions (and a few other places). Instead, cast expressions could be visited by the VarAdder.