Started adding support for return checking and non-returning function annotations

* Reorganized typestate into several modules.

* Made typestate check that any function with a non-nil return type
  returns a value. For now, the check is a warning and not an error
  (see next item).

* Added a "bot" type (prettyprinted as _|_), for constructs like be, ret, break, cont, and
  fail that don't locally return a value that can be inspected. "bot"
  is distinct from "nil". There is no concrete syntax for _|_, while
  the concrete syntax for the nil type is ().

* Added support to the parser for a ! annotation on functions whose
  result type is _|_. Such a function is required to have either a
  fail or a call to another ! function that is reached in all control
  flow paths. The point of this annotation is to mark functions like
  unimpl() and span_err(), so that an alt with a call to err() in one
  case isn't a false positive for the return-value checker. I haven't
  actually annotated anything with it yet.

* Random bugfixes:

* * Fixed bug in trans::trans_binary that was throwing away the
    cleanups for nested subexpressions of an and or or
    (tests: box-inside-if and box-inside-if2).

** In typeck, unify the expected type arguments of a tag with the
   actual specified arguments.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/comp/driver/rustc.rs b/src/comp/driver/rustc.rs
index d538e1711a6..d9d5633d05d 100644
--- a/src/comp/driver/rustc.rs
+++ b/src/comp/driver/rustc.rs
@@ -9,7 +9,7 @@ import middle::trans;
 import middle::resolve;
 import middle::ty;
 import middle::typeck;
-import middle::typestate_check;
+import middle::tstate::ck;
 import back::link;
 import lib::llvm;
 import util::common;
@@ -105,7 +105,8 @@ fn compile_input(session::session sess,
 
     if (sess.get_opts().run_typestate) {
         crate = time(time_passes, "typestate checking",
-                     bind typestate_check::check_crate(crate, def_map));
+                     bind middle::tstate::ck::check_crate(node_type_table,
+                                                          ty_cx, crate));
     }
 
     auto llmod = time[llvm::ModuleRef](time_passes, "translation",