library defined typedef

[Trass3r]

We had a thread where a suggestion was made for a library defined typedef:
enum Type
{
    Independent,
    Super,
    Sub,
    Parallel,
}

struct Typedef( T, Type type = Type.Sub, T init = T.init, string _f =  
__FILE__, int _l = __LINE__ )
{
    T payload = init;

    static if ( type != Type.Independent )
    {
        this( T value )
        {
            payload = value;
        }
    }
    static if ( type == Type.Sub || type == Type.Parallel )
    {
        alias payload this;
    }
    static if ( type == Type.Super )
    {
        typeof( this ) opAssign( T value )
        {
            payload = value;
            return this;
        }
    }
    else static if ( type == Type.Sub )
    {
        @disable void opAssign( T value );
    }
}

One problem is it still lacks proper support for explicit and implicit  
casting.
But will it be included in typecons?
I certainly need a proper solution to this for my coding.