I'm not sure what to make of this. Deftflux has created a library to aid brave C# developers in their dark quests to use duck typing.

Given that C# 3.0 is around the corner with anonymous types I feel the duck typing library is a bold move towards Rubyesque abilities. While anonymous typing only gets you some of the niceties of duck typing, I think the greatest advantage of anonymous types is compiler checking goodness.

There is no doubt duck typing can save a lot of time coding. I admire languages like Ruby for their declarative, artistic form of expression. The .NET framework makes use of it too; duck typing has very real use cases.

The TDD crowd has a distinct advantage over the rest, in that one could happily duck type all day long, trusting in the safety of ones unit tests to provide alerts to type mismatches.

 Sure, if you write a thorough test suite you can theoretically avoid most of the dangers of duck typing. Though all it takes is one hole in the tests and the time saved coding is spent debugging. I would rather my compiler tell me about a type mismatch, than the beta testers complaining of unhandled InvalidCastExceptions. In the spirit of using the right tool for the job, surely the compiler is the right tool to inform us of type mismatch problems? It does a fantastic job of it. Cedric Otaku puts it in a way that's hard to ignore:

In a way that's typical for dynamically typed languages, the error will therefore only appear at runtime and only if such code gets run.

If you are duck typing in copious amounts and not writing tests, then you are walking on shaky ground.

I guess I like to be explicit in general; say what you mean and mean what you say. Life is simpler that way. I like suspense & innuendo in movies, not code. I can't wait for anonymous typing in C#, but perhaps even more so, I look forward to the day work lets me use languages like Spec# to enable me to be even more explicit to the compiler as to my intentions.