This commit reinstates the requirement that the predicate in a
"check" must be a manifest call to a special kind of function
declared with the new "pred" keyword instead of "fn". Preds must
have a boolean return type and can only call other preds; they
can't have any effects (as enforced by the typechecker).
The arguments to a predicate in a check expression must be
slot variables or literals.
Check that the operand in a constraint is an explicit name,
and that the operands are all local variables or literals. Still need
to check that the name refers to a pure function.
This ensures we don't get compile errors on unreachable code (see
test/run-pass/artificial-block.rs for an example of sane code that
wasn't compiling). In the future, we might want to warn about
non-trivial code appearing in an unreachable context, and/or avoid
generating unreachable code altogether (though I'm sure LLVM will weed
it out as well).
There was some confusion on whether the destructors took their
argument by pointer or direct value. They now take it directly, just
like other methods. You no longer get a segfault when a constructor
actually does something with its self value.
This giant commit changes the syntax of Rust to use "assert" for
"check" expressions that didn't mean anything to the typestate
system, and continue using "check" for checks that are used as
part of typestate checking.
Most of the changes are just replacing "check" with "assert" in test
cases and rustc.
Unlike rustboot, rustc keeps it destructors in vtables. Entry 0 holds
either the destructor for the obj or a NULL pointer. The method
offsets start at 1.
I changed instantiate to print out a more helpful error message,
which required passing it a session argument. To avoid
threading extra arguments through a lot of functions,
I added a session field to ty_ctxt.
In rustc, nested patterns were potentially matching when they shouldn't
match, because a loop index wasn't being incremented. Fixed it and added
one test case.
Added support for self_method, cont, chan, port, recv, send, be,
do_while, spawn, and ext; handled break and cont correctly.
(However, there are no non-xfailed test cases for ext or spawn in
stage0 currently.)
Although the standard library compiles and all test cases pass with
typestate enabled, I left typestate checking disabled as rustc
terminates abnormally when building the standard library if so,
even though it does generate code correctly.
