checker/tests/nullness/Issue3622.java

// Test case for https://tinyurl.com/cfissue/3622

// @skip-test until the issue is fixed

import java.util.List;
import org.checkerframework.checker.nullness.qual.Nullable;

public class Issue3622 {

  // These currently pass (no warnings)

  public class ImmutableIntList1 {

    @Override
    public boolean equals(@Nullable Object obj1) {
      if (obj1 instanceof ImmutableIntList1) {
        return true;
      } else {
        return obj1 instanceof List;
      }
    }
  }

  public class ImmutableIntList2 {

    @Override
    public boolean equals(@Nullable Object obj2) {
      return obj2 instanceof ImmutableIntList2;
    }
  }

  public class ImmutableIntList3 {

    @Override
    public boolean equals(@Nullable Object obj3) {
      if (obj3 instanceof ImmutableIntList3) {
        return true;
      } else {
        return false;
      }
    }
  }

  public class ImmutableIntList7 {

    @Override
    public boolean equals(@Nullable Object obj7) {
      return obj7 instanceof ImmutableIntList7 ? true : false;
    }
  }

  public class ImmutableIntList8 {

    @Override
    public boolean equals(@Nullable Object obj8) {
      return obj8 instanceof ImmutableIntList8 ? true : obj8 instanceof List;
    }
  }

  public class ImmutableIntList9 {

    @Override
    public boolean equals(@Nullable Object obj9) {
      return obj9 instanceof ImmutableIntList9
          ? obj9 instanceof ImmutableIntList9
          : obj9 instanceof ImmutableIntList9;
    }
  }

  // These currently fail (false positive warnings)

  public class ImmutableIntList4 {

    @Override
    @SuppressWarnings(
        "contracts.conditional.postcondition" // TODO: give `if` the BOTH_TO_THEN treatment like ?:
    )
    public boolean equals(@Nullable Object obj4) {
      boolean b;
      if (obj4 instanceof ImmutableIntList4) {
        b = true;
      } else {
        b = false;
      }
      return b;
    }
  }

  public class ImmutableIntList5 {

    @Override
    @SuppressWarnings(
        "contracts.conditional.postcondition" // TODO: Need special treatment for true and false
    // boolean  literals (cut off dead parts of graph).
    )
    public boolean equals(@Nullable Object obj5) {
      return true ? obj5 instanceof ImmutableIntList5 : obj5 instanceof ImmutableIntList5;
    }
  }

  public class ImmutableIntList6 {

    @Override
    @SuppressWarnings("contracts.conditional.postcondition" // TODO: Need special treatment
    // for true and false boolean  literals (cut off dead parts of graph).
    )
    public boolean equals(@Nullable Object obj6) {
      return true ? obj6 instanceof ImmutableIntList6 : false;
    }
  }
}