What is typestate?

Question

What does TypeState refer to in respect to language design? I saw it mentioned in some discussions regarding a new language by mozilla called Rust.

Answer 1

There's a typestate checker written for Java, and Adam Warski's explanatory page gives some useful information. I'm only just figuring this material out myself, but if you are familiar with QuickCheck for Haskell, the application of QuickCheck to monadic state seems similar: categorise the states and explain how they change when they are mutated through the interface.