checker/tests/nullness/generics/WildcardSubtyping2.java

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

public class WildcardSubtyping2 {
  class MyClass {}

  class MyCloneClass extends MyClass implements Cloneable {}

  class MyGeneric<@NonNull T extends @Nullable MyClass> {}

  class UseMyGeneric {
    MyGeneric<@NonNull MyCloneClass> nonNull = new MyGeneric<>();
    MyGeneric<@Nullable MyCloneClass> nullable = new MyGeneric<>();

    MyGeneric<? extends @NonNull Cloneable> interfaceNN = nonNull;
    MyGeneric<? extends @Nullable Cloneable> interfaceNull = nullable;
  }

  class MyGenericEB<@NonNull T extends @NonNull MyClass> {}

  class UseMyGenericEB {
    MyGenericEB<@NonNull MyCloneClass> nonNull = new MyGenericEB<>();
    // :: error: (type.argument)
    MyGenericEB<@Nullable MyCloneClass> nullable = new MyGenericEB<>();

    MyGenericEB<? extends @NonNull Cloneable> interfaceNN = nonNull;
    MyGenericEB<? extends @Nullable Cloneable> interfaceNull = nullable;
  }
}