If you use a function expecting an alias argument in a context that
expects a function expecting a value argument, or vice versa, the
previous error message complained that the number of arguments was
wrong. Fixed the error message to be accurate.
typestate now drops constraints correctly in the post-state of
a move expression or a declaration whose op is a move. It doesn't
yet drop constraints mentioning variables that get updated.
To do this, I had to change typestate to use trit-vectors instead
of bit-vectors, because for every constraint, there are three
possible values: known-to-be-false (e.g. after x <- y, init(y) is
known-to-be-false), known-to-be-true, and unknown. Before, we
conflated known-to-be-false with unknown. But move requires them
to be treated differently. Consider:
(program a)
(a1) x = 1;
(a2) y <- x;
(a3) log x;
(program b)
(b1) x = 1;
(b2) y <- z;
(b3) log x;
With only two values, the postcondition of statement a2 for
constraint init(x) is the same as that of b2: 0. But in (a2)'s
postcondition, init(x) *must* be false, but in (b2)'s condition,
it's just whatever it was in the postcondition of the preceding statement.
This code was causing a bounds check failure:
fn hd[U](&vec[U] v) -> U {
fn hd1(&vec[U] w) -> U {
ret w.(0);
}
ret hd1(v);
}
because in hd1, U was being treated as if it referred to a type
parameter of hd1, rather than referring to the lexically enclosing binding
for U that's part of hd.
I'm actually not sure whether this is a legit program or not. But I wanted
to get rid of the bounds check error, so I assumed that program shouldn't
compile and made it a proper error message.
This involved, in part, changing the ast::def type so that a def_fn
has a "purity" field. This lets the typechecker determine whether
functions defined in other crates are pure.
It also required updating some error messages in tests. As a test
for cross-crate constrained functions, I added a safe_slice function
to std::str (slice(), with one of the asserts replaced with a
function precondition) and some test cases (various versions of
fn-constraint.rs) that call it. Also, I changed "fn" to "pred" for
some of the boolean functions in std::uint.
This will replace the various node_id-to-node mappings done in several
other passes. This commit already uses the new map in resolve, dropping
the ast_map that was built there before.
This reduces some redundancy in the AST data structures and cruft in
the code that works with them. To get a def_id from a node_id, apply
ast::local_def, which adds the local crate_num to the given node_id.
Most code only deals with crate-local node_ids, and won't have to
create def_ids at all.
Revert "rustc: Export only what's needed from middle::ty"
This reverts commit 4255d58aa5db2a05362c4435a0e807205e1b8ed7.
Revert "rustc: Make name resolution errors less fatal"
This reverts commit b8ab9ea89c16c60237e7660804f4321f59ae0435.
Revert "rustc: Make import resolution errors less fatal"
This reverts commit 92a8ae94b971206bf0502da3dc5f416fcb24cc36.
Revert "rustc: Export only what's used from middle::resolve"
This reverts commit 4539a2cf7ad99851a165c98ed2f4e4a475cffd7d.
Revert "rustc: Re-introduce session.span_err, session.err"
This reverts commit 7fe9a88e31ae07f2fd89f6715efedd7e3edf49e6.
Revert "rustc: Rename session.span_err -> span_fatal, err -> fatal"
This reverts commit c394a7f49ac29a099994e243017065de2ff97f2a.
