@Override
  public Constraint getAfterData(int insn) {
    Constraint afterData = mkAfterData();
    if (notNullInsn == insn) {
      return new Constraint(afterData.calls | notNullCall, afterData.nulls | notNullNull);
    }
    return afterData;
  }
@Override
  public Constraint getAfterData(int insn)