Implicit enum conversions are a stupid PITA

[Lutger]

Lutger wrote:

...
> 
> unittest
> {
>     alias Flags!q{ do_nothing, walk_dog, cook_breakfast, deliver_newspaper,
>         visit_miss_kerbopple, morning_task = walk_dog | cook_breakfast,
>         wash_covers } Todo;
> 
>     Todo list1 = Todo.do_nothing;
>     assert( list1 == 1 );
>     list1 |= Todo.wash_covers | Todo.walk_dog;
>     assert(list1 == Todo.do_nothing | Todo.wash_covers | Todo.walk_dog);
>     assert(Todo.do_nothing in list1);
> 
>     Todo list2 = Todo.cook_breakfast | Todo.wash_covers;
>     assert( list1 & list2 == Todo.do_nothing | Todo.cook_breakfast);
>     list1 = list2;
>     assert(list1 == Todo.do_nothing | Todo.wash_covers | Todo.walk_dog);
> 
>     assert( Todo.morning_task == Todo.walk_dog | Todo.cook_breakfast );
> 
>     auto list3 = Todo.deliver_newspaper;
>     assert(Todo.deliver_newspaper in list3, "can't infer type properly");
>     /*
> bug */
> }

        ^ 
oops, this one is totally messed up and needs to go to precedence school. 
This should be better:

unittest
{
    alias Flags!q{ do_nothing, walk_dog, cook_breakfast, deliver_newspaper,
                   visit_miss_kerbopple, morning_task = walk_dog | 
cook_breakfast, wash_covers } Todo;

    Todo list1 = Todo.do_nothing;
    assert( list1 == 1 );
    list1 |= Todo.wash_covers | Todo.walk_dog;
    assert(list1 == (Todo.do_nothing | Todo.wash_covers | Todo.walk_dog) );
    assert(Todo.do_nothing in list1);

    Todo list2 = Todo.cook_breakfast | Todo.wash_covers;
    assert( (list1 & list2) == Todo.wash_covers );
    list1 = list2;
    assert(list1 == (Todo.cook_breakfast | Todo.wash_covers) );

    assert( Todo.morning_task == (Todo.walk_dog | Todo.cook_breakfast) );

    auto list3 = Todo.deliver_newspaper;
    /* bug */
    assert(Todo.deliver_newspaper in list3, "can't infer type properly");
}