fn void test1()
{
    short? a = 1;
    @ok(+a);
    short b = +a; // #error: 'short?' to 'short'.
}

fn void test2()
{
    int? a = 1;
    @ok(+a);
    int b = +a; // #error: 'int?' to 'int'
}

fn void test3()
{
    long? a = 1;
    @ok(+a);
    long b = +a; // #error: 'long?' to 'long'
}


fn void test4()
{
	int a = 1;
	+a = 3; // #error: An assignable expression
}