implicit constructors

[Trass3r]

Wasn't there some discussion quite some time ago about introducing an  
implicit/@implicit tag similar to C++'s explicit, just the other way  
around?

I know there's alias this, but what if you don't store the value directly?
struct A
{
        int store;
        this(int a)
        {
                store = a << 16;
                ...
        }
}

A a = 5;