NullableLUB.java

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

/* Test case that illustrated an unsoundness in the unification of
 * type variables with non-type variables. The error did not previously
 * get raised, leading to a missed NPE.
 */
//:: error: (initialization.fields.uninitialized)
public class NullableLUB<T extends @Nullable Object> {
    T t;
    @Nullable T nt;

    T m(boolean b, T p) {
        T r1 = b ? p : null;
        nt = r1;
        //:: error: (assignment.type.incompatible)
        t = r1;
        //:: error: (return.type.incompatible)
        return r1;
    }

    public static void main(String[] args) {
        new NullableLUB<@NonNull Object>().m(false, new Object()).toString();
    }

    T m2(boolean b, T p) {
        T r1 = b ? null : p;
        nt = r1;
        //:: error: (assignment.type.incompatible)
        t = r1;
        //:: error: (return.type.incompatible)
        return r1;
    }
}