Uncle Bob, you recently wrote a post titled Types And Tests. It generated quite a lot of buzz. It was also, in my opinion, a bit naive regarding the current state of affairs in type systems. This made it difficult for me to understand exactly what your points were and I would like to understand those better. To help clarify those I'm going to provide counter examples to your claims and propose other questions that both might help me better understand what you mean. Hopefully someone else finds this useful as well. I'll be using Ruby and Haskell for most code snippets as they are representative of the two sides and I'm most familiar with them right now.
ruby-1.9.3-p327 cumulative performance patch for rbenv
This installs a patched ruby 1.9.3-p327 with various performance improvements and a backported COW-friendly GC, all courtesy of funny-falcon.
You will also need a C Compiler. If you're on Linux, you probably already have one or know how to install one. On OS X, you should install XCode, and
brew install autoconf using homebrew.