hygiene for `self` will be tricky

[jbclements]

Hygiene for self will be a bit tricky. In particular, the AST doesn't actually contain a binding identifier for self, which means that the resolver doesn't actually have identifiers that can be compared hygienically.

I believe that getting hygiene to work correctly for self will involve equipping the Method node with a self identifier, and then performing a hygienic comparison in resolution.

[jbclements]

Wow, I'm totally wrong! It works out of the box! Magnificent.

[jbclements]

ooh... spoke too soon. The FnDecl does contain an explicit arg for self, but renaming causes something to break.