// UnOp
class UnOpTest {
    Null foo() {
        Int x = 2;
        Null z = null;
        -y; // 1/2 failure of clause 1 (nonexistent ident)
        -z; // 2/2 failure of clause 1 (ident not of type Int)
        -x; // success
        !x; // success
    }
}

1