Lambda the Ultimate

It has been mentioned several times here and there in LtU discussion comments, but search didn't show it as a full topic. Which seems sad to me since this is just mind blowingly awesome stuff to me. Here's work that takes something in the UX realm and applies big brains to it and gives really measurable improvements.

Diagnosing Type Errors with Class:

Type inference engines often give terrible error messages, and the more sophisticated the type system the worse the problem.

...it is possible to identify the most likely source of the type error, rather than the first source that the inference engine trips over.

...Using a large corpus of Haskell programs, we show that this error localization technique is practical and significantly improves accuracy over the state of the art.