ArrayLazyNN.java

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

/* Use @MonotonicNonNull as component type to ensure that null can never be
 * assigned into a component. Then, after a single iteration over the array,
 * we can be sure that all elements are non-null.
 * TODO: support for (i=0; i < a.lenght.... and change component type to non-null.
 */
class ArrayLazyNN {
    void test1() {
        @MonotonicNonNull Object[] o1 = new @MonotonicNonNull Object[10];
        o1[0] = new Object();
        //:: error: (assignment.type.incompatible)
        o1[0] = null;
        //:: error: (assignment.type.incompatible)
        @NonNull Object[] o2 = o1;
        @SuppressWarnings("nullness")
        @NonNull Object[] o3 = o1;
    }
}