checker/tests/nullness-genericwildcard/Issue511.java

// Additional test case for issue #511:
// https://github.com/typetools/checker-framework/issues/511
class MyGeneric<T extends Number> {}

class MySuperClass {
  public void method(MyGeneric<? extends Object> x) {}
}

public class Issue511 extends MySuperClass {
  @Override
  public void method(MyGeneric<?> x) {
    super.method(x);
  }

  // public void method(MyGeneric<? extends Number> x) {}
  // On the above method, javac issues the following error:
  // Issue511.java:19: error: name clash: method(MyGeneric<? extends Number>) in Issue511 and
  // method(MyGeneric<? extends Object>) in MySuperClass have the same erasure, yet neither
  // overrides the other
  // public void method(MyGeneric<? extends Number> x) {}
  //    ^
  //            1 error

}

class Use {
  MyGeneric<? extends Object> wildCardExtendsObject = new MyGeneric<>();
  MyGeneric<? extends Number> wildCardExtendsNumber = wildCardExtendsObject;
  MyGeneric<?> wildCardNoBound = new MyGeneric<>();
  MyGeneric<? extends Number> wildCardExtendsNumber2 = wildCardNoBound;
}