Tutorial: comment on how mutability applies to boxes
Tutorial: fix typo
refactor check_call_inner to have a better name and be readable
Move the replacement of bound regions out from `check_arguments` and into check_call / method_resolution
Rather than storing a list of ty::method per trait, store one ty::method
per method and list of def-ids per trait.
Compute a ty::method for methods that appear in impls as well
Pass around a pointer to the ty::method rather than the individual bits of info
Add a (currently unused) "transformed self type" pointer into ty::method
Refactor so that references to traits are not represented using a type with a
bare function store (which is not in fact a kind of value) but rather
ty::TraitRef.  Removes many uses of fail!() and other telltale signs of
type-semantic mismatch.

cc #4183 (not a fix, but related)
Fix various warnings, NOTEs, etc
Add comment explaining method visibility
rustc: Be careful about calls to fn types that contain nested errors
Tutorial: spelling correction and move a failing test to an xfail-test marked code block.
auto merge of #5676 : nikomatsakis/rust/issue-4183-trait_ref, r=nikomatsakis

These are a number of incremental steps towards #4183 and #4646.
auto merge of #5721 : dhardy/rust/master, r=graydon

This is some stuff which seemed to be missing to me (though I haven't read everything yet so hope I haven't missed the relevant section).

A similar addition for borrowing handles is needed, but #5720 stumped me.

Comments welcome.
rt: Move test functions to rust_test_helpers.cpp
rustc: Use an out pointer to return structs in x86 C ABI. #5347

This Adds a bunch of tests for passing and returning structs
of various sizes to C. It fixes the struct return rules on unix,
and on windows for structs of size > 8 bytes. Struct passing
on unix for structs under a certain size appears to still be broken.