checker/tests/interning/Polymorphism.java

import java.lang.ref.WeakReference;
import java.util.Date;
import java.util.List;
import java.util.Map;
import org.checkerframework.checker.interning.qual.*;

public class Polymorphism {
  // Test parameter
  public @PolyInterned String identity(@PolyInterned String s) {
    return s;
  }

  void testParam() {
    String notInterned = new String("not interned");
    @Interned String interned = "interned";

    interned = identity(interned);
    // :: error: (assignment)
    interned = identity(notInterned); // invalid
  }

  // test as receiver
  @PolyInterned Polymorphism getSelf(@PolyInterned Polymorphism this) {
    return this;
  }

  void testReceiver() {
    Polymorphism notInterned = new Polymorphism();
    @Interned Polymorphism interned = null;

    interned = interned.getSelf();
    // :: error: (assignment)
    interned = notInterned.getSelf(); // invalid
  }

  // Test assinging interned to PolyInterned
  public @PolyInterned String always(@PolyInterned String s) {
    if (s.equals("n")) {
      // This code type-checkd when the hierarchy contained just @UnknownInterned and
      // @Interned, but no longer does because of @InternedDistinct.
      // :: error: (return)
      return "m";
    } else {
      // :: error: (return)
      return new String("m"); // invalid
    }
  }

  public static @PolyInterned Object[] id(@PolyInterned Object[] a) {
    return a;
  }

  public static void idTest(@Interned Object @Interned [] seq) {
    @Interned Object[] copy_uninterned = id(seq);
  }

  private static Map<
          List<@Interned String @Interned []>, WeakReference<@Interned String @Interned []>>
      internedStringSequenceAndIndices;
  private static List<@Interned String @Interned []> sai;
  private static WeakReference<@Interned String @Interned []> wr;

  public static void testArrayInGeneric() {
    internedStringSequenceAndIndices.put(sai, wr);
  }

  // check for a crash when using raw types
  void processMap(Map<String, String> map) {}

  void testRaw() {
    Map m = null;
    // TODO: RAW TYPES WILL EVENTUALLY REQUIRE THAT THERE BOUNDS BE EXACTLY THE QUALIFIER
    // EXPECTED.
    // :: warning: [unchecked] unchecked method invocation: method processMap in class
    // Polymorphism is applied to given types :: warning: [unchecked] unchecked conversion
    processMap(m);
  }

  // test anonymous classes
  private void testAnonymous() {
    new Object() {
      @org.checkerframework.dataflow.qual.Pure
      public boolean equals(Object o) {
        return true;
      }
    }.equals(null);

    Date d = new Date() {};
  }
}