checker/tests/nullness/generics/GenericsBounds1.java

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

interface GBList<E extends @Nullable Object> {
  void add(E p);
}

/*
 * Illustrate a problem with annotations on type variables.
 * The annotation on the upper bound of a type variable is confused with an
 * annotation on the type variable itself.
 */
public class GenericsBounds1<X extends @Nullable Object> {
  void m1(@NonNull GBList<X> g1, @NonNull GBList<@Nullable X> g2) {
    // :: error: (assignment)
    g1 = null;
    // :: error: (argument)
    g1.add(null);

    // :: error: (assignment)
    g2 = null;
    g2.add(null);

    // :: error: (assignment)
    g2 = g1;
    g2.add(null);
  }
}