define Eq,TotalEq,Ord,TotalOrd for &mut T

Also Show, which is useful in assertions. Fixes #14074
Print 'rustc' and 'rustdoc' as the command name for --version

Instead of just blindly printing arg[0], use a constant string.
Partial fix for #13582
auto merge of #14133 : db48x/rust/ord-for-mut-refs, r=alexcrichton

Also Show, which is useful in assertions. Fixes #14074
auto merge of #14162 : brson/rust/fixvercmd, r=brson

Instead of just blindly printing arg[0], use a constant string.

Partial fix for #13582
syntax::visit: pub `walk_explicit_self` so impls can call it as defaults do.

drive-by: added some doc.
Teach SVH computation to ignore more implementation artifacts.

In particular, this version of strict version hash (SVH) works much
like the deriving(Hash)-based implementation did, except that uses a
content-based hash that filters rustc implementation artifacts and
surface syntax artifacts.

Fix #14132.
Some basic acceptance tests for better SVH.
A test case for a bug I found in the new SVH while reviewing it.

Namely: non-pub `use` declarations *are* significant to the SVH
computation, since they can change which traits are part of the method
resolution step, and thus affect which methods get called from the
(potentially inlined) code.
Added tests checking that changes in type sig are recognized in SVH.

(Only after adding the tests did I realize that this is not really a
special case at the AST level; as far as the visitor is concerned,
`int` and `i32` and `i64` are just idents.)
auto merge of #14145 : pnkfelix/rust/fsk-better-svh-via-visitor, r=alexcrichton

Teach SVH computation to ignore more implementation artifacts.

In particular, this version of strict version hash (SVH) works much
like the deriving(Hash)-based implementation did, except that it
deliberately:

  1. skips over content known not affect the generated crates, and,

  2. uses a content-based hash for names instead of using the value of
     the `Name` index itself, which can differ depending on the order
     in which strings are interned (which in turn is affected by
     e.g. the presence of `--cfg` options on the command line).

Fix #14132.
test: implement a no-alloc -> &str method for TestName.

This is far cheaper than the `.to_str` technique that was used previously.
test: allow the test filter to be a regex.

This is fully backwards compatible, since test names are Rust
identifiers + `:`, and hence not special regex characters.

Fixes #2866.
test: ensure that the extended usage description gets printed.

Previously the longer hand-written usage string was never being printed:
theoretically it was trying to detect when precisely `--help` was
passed (but not `-h`), but the getopts framework was considering a check
for the presence of `-h` to be a check for that of `--help` too,
i.e. the code was always going through the `-h` path.

This changes it to print the extended usage for both `-h` and `--help`,
meaning that it does actually appear correctly.
std:: switch the order in which dynamic_lib adds search paths.

The compiler needs to be opening e.g. libregex in the correct directory,
which requires getting these in the right order.