Feedback request for #9628 AST Annotations

[Edward Z. Yang]

Excerpts from Alan & Kim Zimmerman's message of 2014-09-29 13:38:45 -0700:
> 1. Is this change too big, should I scale it back to just update the
>    HsSyn structures and then lock it down to Located SrcSpan for all
>    the rest?

I don't claim to speak for the rest of the GHC developers, but I think
this change is too big.  I am almost tempted to say that we shouldn't
add the type parameter at all, and do something else (maybe Backpack
can let us extend SrcSpan in a modular way, or even use a dynamically
typed map for annotations.)

Edward