codeql/java/ql/test/library-tests/dataflow/sign-analysis/A.java

public class A {
  int f1(int x, int y) {
    if (x < 0) {
      return x; // strictly negative
    }
    if (x < y) {
      return y; // y is strictly positive because of the bound on x above
    }

    return 0;
  }

  void unsigned(int x) {
    char c = (char)x;
    System.out.println(c); // positive
  }
}