Further work on typestate_check

Lots of work on typestate_check, seems to get a lot of the way
through checking the standard library.

* Added for, for_each, assign_op, bind, cast, put, check, break,
and cont. (I'm not sure break and cont are actually handled correctly.)

* Fixed side-effect bug in seq_preconds so that unioning the
preconditions of a sequence of statements or expressions
is handled correctly.

* Pass poststate correctly through a stmt_decl.

* Handle expr_ret and expr_fail properly (after execution of a ret
or fail, everything is true -- this is needed to handle ifs and alts
where one branch is a ret or fail)

* Fixed bug in set_prestate_ann where a thing that needed to be
mutated wasn't getting passed as an alias

* Fixed bug in how expr_alt was treated (zero is not the identity
for intersect, who knew, right?)

* Update logging to reflect log_err vs. log

* Fixed find_locals so as to return all local decls and exclude
function arguments.

* Make union_postconds work on an empty vector (needed to handle
empty blocks correctly)

* Added _vec.cat_options, which takes a list of option[T] to a list
of T, ignoring any Nones

* Added two test cases.

2 files changed, 42 insertions, 0 deletions

diff --git a/src/test/run-pass/use-uninit-alt.rs b/src/test/run-pass/use-uninit-alt.rs
new file mode 100644
index 00000000..a7c77bba
--- /dev/null
+++ b/src/test/run-pass/use-uninit-alt.rs
@@ -0,0 +1,21 @@
+fn foo[T](&myoption[T] o) -> int {
+  let int x = 5;
+
+  alt (o) {
+    case (none[T]) { }
+    case (some[T](?t)) {
+      x += 1;
+    }
+  }
+  
+  ret x;
+}
+
+tag myoption[T] {
+  none;
+  some(T);
+}
+
+fn main() {
+  log(5);
+}
\ No newline at end of file
diff --git a/src/test/run-pass/use-uninit-alt2.rs b/src/test/run-pass/use-uninit-alt2.rs
new file mode 100644
index 00000000..36514d13
--- /dev/null
+++ b/src/test/run-pass/use-uninit-alt2.rs
@@ -0,0 +1,21 @@
+fn foo[T](&myoption[T] o) -> int {
+  let int x;
+
+  alt (o) {
+    case (none[T]) { fail; }
+    case (some[T](?t)) {
+      x = 5;
+    }
+  }
+  
+  ret x;
+}
+
+tag myoption[T] {
+  none;
+  some(T);
+}
+
+fn main() {
+  log(5);
+}
\ No newline at end of file