Adding Type Annotations to Ruby Syntax

I would like to add type annotations to Ruby, per the ideas list. These annotations will serve as documentation and hopefully a way to implement basic typechecking for third party tools. Following the guidelines posted in the Ideas page, the project will consist of 3 parts: adding the type information to the parser generator, modifying Ripper to emit the type annotation information with the parse tree, and writing a detailed proposal to add this feature to a future version of MRI.