On Mon, Mar 5, 2012 at 08:52, Stephen Tetley wrote:

How do I add type annotations to interior locations in an abstract syntax tree?

I use an annotated expression tree in my work. The nodes of the AST are annotated with the type, assumption set, and constraint set as described in constraint-based type inference [1]. We have a paper describing our type-and-transform system [2] and a link in the paper points to the code. Let me know if you have any questions.