It's still sketchy. I added a typestate annotation field to statements
tagged stmt_decl or stmt_expr, because a stmt_decl statement has a typestate
that's different from that of its child node. This necessitated trivial
changes to a bunch of other files all over to the compiler. I also added a
few small standard library functions, some of which I didn't actually end
up using but which I thought might be useful anyway.
The last few pieces of the hack that lets us use trans.trans_call() to
translate self-calls, plus a fix for the parser buy that was
preventing self-call expressions from getting past parsing.
test/run-pass/obj-self.rs works now (as in it actually prints "hi!"
twice!).
Mostly:
* Merciless refactoring of trans.rs so that trans_call can work for
self-calls as well as other kinds of calls
Also:
* Various changes to go with having idents, rather than exprs, in
expr_call_self AST nodes
* Added missing case for SELF token to token.to_str()
I don't don't totally understand the implications of this but it makes the
behavior consistent for all live edges, which is going to make joining the
arms of an alt expression work correctly.
I added a new field to the ast "ann" type for typestate information.
Currently, the field contains a record of a precondition bit vector and
postcondition vector, but I tried to structure things so as to make
it easy to change the representation of the typestate annotation type.
I also had to add annotations to some syntactic forms that didn't have
them before (fail, ret, be...), with all the boilerplate changes
that that would imply.
The main call to the typestate_check entry point is commented out and
the actual pre-postcondition algorithm only has a few cases
implemented, though the overall AST traversal is there. The rest of
the typestate algorithm isn't implemented yet.
This allows blocks to be used in conditional constructs where the block may
not ever execute: the drop glue will notice that it was never used and ignore
it.
Also, beef up the comments.
