import java.util.LinkedList;
import java.util.prefs.*;
import org.checkerframework.checker.interning.qual.Interned;
import org.checkerframework.checker.interning.qual.UsesObjectEquals;

public class UsesObjectEqualsTest {

  public @UsesObjectEquals class A {
    public A() {}
  }

  @UsesObjectEquals
  class B extends A {}

  // :: error: (overrides.equals)
  class B2 extends A {
    @Override
    public boolean equals(Object o) {
      return super.equals(o);
    }
  }

  @UsesObjectEquals
  class B3 extends A {
    @Override
    public boolean equals(Object o3) {
      return this == o3;
    }
  }

  @UsesObjectEquals
  class B4 extends A {
    @Override
    public boolean equals(Object o4) {
      return o4 == this;
    }
  }

  // changed to inherited, no (superclass.annotated) warning
  class C extends A {}

  class D {}

  @UsesObjectEquals
  // :: error: (superclass.notannotated)
  class E extends D {}

  @UsesObjectEquals
  // :: error: (overrides.equals)
  class TestEquals {

    @org.checkerframework.dataflow.qual.Pure
    public boolean equals(Object o) {
      return true;
    }
  }

  class TestComparison {

    public void comp(@Interned Object o, A a1, A a2) {
      if (a1 == a2) {
        System.out.println("one");
      }
      if (a1 == o) {
        System.out.println("two");
      }
      if (o == a1) {
        System.out.println("three");
      }
    }
  }

  @UsesObjectEquals
  class ExtendsInner1 extends UsesObjectEqualsTest.A {}

  class ExtendsInner2 extends UsesObjectEqualsTest.A {}

  class MyList extends LinkedList {}

  class DoesNotUseObjectEquals {
    @Override
    public boolean equals(Object o) {
      return super.equals(o);
    }
  }

  @UsesObjectEquals
  class SubclassUsesObjectEquals extends DoesNotUseObjectEquals {
    @Override
    public boolean equals(Object o) {
      return this == o;
    }
  }
}