import org.checkerframework.checker.nullness.qual.*;

public class FlowCompound {

  @org.checkerframework.dataflow.qual.Pure
  public boolean equals(@Nullable Object o) {
    return o != null && this.getClass() != o.getClass();
  }

  void test(@Nullable String s) {

    if (s == null || s.length() > 0) {
      // :: error: (assignment)
      @NonNull String test = s;
    }

    String tmp;
    @NonNull String notNull;
    tmp = "hello";
    notNull = tmp;
    notNull = tmp = "hello";
  }

  public static boolean equal(@Nullable Object a, @Nullable Object b) {
    assert b != null : "suppress nullness";
    return a == b || (a != null && a.equals(b));
  }

  public static void testCompoundAssignmentWithString() {
    String s = "m";
    s += "n";
    s.toString();
  }

  public static void testCompoundAssignmentWithChar() {
    String s = "m";
    s += 'n';
    s.toString();
  }

  public static void testCompoundAssignWithNull() {
    String s = "m";
    s += null;
    s.toString();
  }

  public static void testPrimitiveArray() {
    int[] a = {0};
    a[0] += 2;
    System.out.println(a[0]);
  }

  public static void testPrimitive() {
    Integer i = 1;
    i -= 2;
  }
}