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digitalmars.D.learn - Duck typing with std.variant.Algebraic/Variant


I wonder why I can't use Algebraic like this:

     struct Foo(bool flag)
         size_t bar() { return flag ? 42 : 0; }

     Foo!false f;
     Foo!true t;
     Algebraic!(typeof(t), typeof(f)) v;
     v = t;
     Variant i = v.bar(); // or an Algebraic of the return types. 
This doesn't compile anyway
     assert(i.type == typeof(size_t));
     assert(i.get!size_t() == 42);

Essentially what I miss is opDispatch implemented on Variant. 
There seemed to be a discussion with a proposal for an Any type 
in std.typecons some time ago 
(http://forum.dlang.org/thread/20100708100757.GA4412 dsource), 
but for some reason none of it has made it into Phobos.

Can anyone explain about why it isn't implemented? Seems like I 
missed something...
Apr 20 2013