Get rid of an unused variable warning.
Fix a default method polymorphism bug.
Add a to_owned_vec method to IteratorUtil.
Refactor a bunch of lookup_vtable to reduce rightward drift and clean things up.
Improve vtable resolution.

Improve vtable resolution in a handful of ways.  First, if we don't
find a vtable for a self/param type, do a regular vtable search.  This
could find impls of the form "impl for A". Second, we don't require
that types be fully resolved before looking up subtables, and we
process tables in reverse order. This allows us to gain more
information about early type parameters based on how they are used by
the impls used to resolve later params.

Closes #6967, I believe.
Fix some impls such that all supertraits are actually implemented.
Have vtable resolution check for supertrait bounds. Closes #4055.
Properly track and export information about vtables for impls in metadata.

Partially rework how vtables are handled in default method calls.
Closes #7460.
Major rework of how calls to self and super methods work.

Eliminates method_super, method_self, and vtable_self, merging all of
them into the param cases.
Cloes #4396. Closes #7301.
Fix the issue-3979 tests and add a new test.
Change each_bound_trait_and_supertraits to take a vec of TraitRefs.
Tests select when to use --cfg debug, regardless of configure settings.
Remove directive, if present, from CFG_RUSTC_FLAGS.

Fix #7898.

(One alternative tack is to build up distinct CFG_TEST_RUSTC_FLAGS
alongside CFG_RUSTC_FLAGS; but currently debug is the only --cfg flag
ever added to CFG_RUSTC_FLAGS; the other contents of CFG_RUSTC_FLAGS
are a mix of -Z flags and a few other switches like O, which seem to
make sense to propogate to the tests.)
Implement std::num::Zero for bool
Closes #8024.
Generalize the `ty::substs` struct so that it can represent
multiple lifetime parameters, and not just one. Also add an option
for erasing lifetimes, which makes trans code somewhat simpler
and cleaner.
Check for comparisons to NaN in patterns

For every pattern that refers to a static value, evaluate it and emit a warning
if it is a NaN.

Fixes #6804
Generalize NaN pattern detection using walk_pat
rm unused upcall_exchange_free
rm default method lint

default methods are enabled by default, so there's not much point in
keeping around a lint to report them as being experimental
improve container/iterator tutorial
rewrite rust-mode to use font-lock-mode and emacs builtin syntax analysis