If the channel is associated with a port then the destructor will assert.
Additionally, destruction of the object is not always appropriate. This brings
the deref() method into sync with the behavior of generated rust code which
only invokes destroy() once the reference count goes to 0.
The macro with the extra dtor parameter is intended for structures like
rust_chan which may not necessarily delete themselves when the ref count
becomes 0. This functionality will be used in an upcoming changeset.
Only link attributes of the meta_list type are considered when matching crate
attributes. Instead of doing nothing we can at least log that link attributes
of other types were ignored.
(Using the * operator.)
This makes tags more useful as nominal 'newtype' types, since you no
longer have to copy out their contents (or construct a cumbersome
boilerplate alt) to access them.
I could have gone with a scheme where you could dereference individual
arguments of an n-ary variant with ._0, ._1, etc, but opted not to,
since we plan to move to a system where all variants are unary (or, I
guess, nullary).
This is a preparation for tags-as-nominal-types. A tag that has only a
single variant is now represented, at run-time, as simply a tuple of
the variant's parameters, with the variant id left off.
This is important since we are going to be making functions noncopyable
soon, which means we'll be seeing a lot of boxed functions.
(*f)(...) is really just too heavyweight.
Doing the autodereferencing was a very little bit tricky since
trans_call works with an *lval* of the function whereas existing
autoderef code was not for lvals.
Modify typestate to check for unused variables and emit warnings
where relevant. This exposed a (previously harmless) bug in
collect_locals where outer functions had bit-vector entries
for init constraints for variables declared in their inner
nested functions. Fixing that required changing collect_locals to
use visit instead of walk -- probably a good thing anyway.
