vim: Tweak how comment nesting works

Don't try to match line comments inside of a comment block. That makes
no sense and can highlight differently for people who override their
highlights.

Similarly, don't match a doc-comment inside of a comment block. It
shouldn't be highlighted differently unless it's actually a doc-comment
(and nested comments are obviously not doc comments).

Fixes #12307.
Mark top level module as a crate in rustdoc, closes #12507
Add `time` crate to index, expand docs of `test`.
auto merge of #12621 : huonw/rust/time-test-doc, r=pnkfelix

Add `time` crate to index, expand docs of `test`.
rustc: implement a lint for publicly visible private types.

These are types that are in exported type signatures, but are not
exported themselves, e.g.

    struct Foo { ... }

    pub fn bar() -> Foo { ... }

will warn about the Foo.

Such types are not listed in documentation, and cannot be named outside
the crate in which they are declared, which is very user-unfriendly.

cc #10573
sync: Rename arc::Condvar to arc::ArcCondvar.

The sync submodule also has a `Condvar` type, and its reexport was
shadowing the `arc` type, making it crate-private.
Publicise types/add #[allow(visible_private_types)] to a variety of places.

There's a lot of these types in the compiler libraries, and a few of the
older or private stdlib ones. Some types are obviously meant to be
public, others not so much.
Improve vec `partition` and `partitioned` method doc.

Explicitly note in vec `partition` and `partitioned` that the left and
right parts each map to satisfying and non-satisfying elements.
auto merge of #12595 : huonw/rust/pub-vis-typ, r=alexcrichton

These are types that are in exported type signatures, but are not
exported themselves, e.g.

    struct Foo { ... }

    pub fn bar() -> Foo { ... }

will warn about the Foo.

Such types are not listed in documentation, and cannot be named outside
the crate in which they are declared, which is very user-unfriendly.

cc #10573.
auto merge of #12622 : pnkfelix/rust/fsk-improve-vec-partition-doc, r=huonw

Explicitly note in vec `partition` and `partitioned` that the left and
right parts each map to satisfying and non-satisfying elements.
std: Add cfg(test) to UnsafeArc assertions

This is a ubiquitous type in concurrent code, and the assertions are causing
significant code bloat for simple operations such as reading the pointer
(injecting a failure point, etc).

I am testing executable sizes with no I/O implementations (everything stubbed
out to return nothing), and this took the size of a libnative executable from
328K to 207K (37% reduction in size), so I think that this is one assertion
that's well worth configuring off for now.
rustc: Simplify crate loading constraints

The previous code passed around a {name,version} pair everywhere, but this is
better expressed as a CrateId. This patch changes these paths to store and pass
around crate ids instead of these pairs of name/version. This also prepares the
code to change the type of hash that is stored in crates.
rustc: Add the concept of a Strict Version Hash

This new SVH is used to uniquely identify all crates as a snapshot in time of
their ABI/API/publicly reachable state. This current calculation is just a hash
of the entire crate's AST. This is obviously incorrect, but it is currently the
reality for today.

This change threads through the new Svh structure which originates from crate
dependencies. The concept of crate id hash is preserved to provide efficient
matching on filenames for crate loading. The inspected hash once crate metadata
is opened has been changed to use the new Svh.

The goal of this hash is to identify when upstream crates have changed but
downstream crates have not been recompiled. This will prevent the def-id drift
problem where upstream crates were recompiled, thereby changing their metadata,
but downstream crates were not recompiled.

In the future this hash can be expanded to exclude contents of the AST like doc
comments, but limitations in the compiler prevent this change from being made at
this time.

Closes #10207
syntax: Expand format!() deterministically

Previously, format!("{a}{b}", a=foo(), b=bar()) has foo() and bar() run in a
nondeterminisc order. This is clearly a non-desirable property, so this commit
uses iteration over a list instead of iteration over a hash map to provide
deterministic code generation of these format arguments.
std: Improve some I/O documentation

This lowers the #[allow(missing_doc)] directive into some of the lower modules
which are less mature. Most I/O modules now require comprehensive documentation.
auto merge of #12533 : alexcrichton/rust/svh, r=brson

These hashes are used to detect changes to upstream crates and generate errors which mention that crates possibly need recompilation.

More details can be found in the respective commit messages below. This change is also accompanied with a much needed refactoring of some of the crate loading code to focus more on crate ids instead of name/version pairs.

Closes #12601
syntax: Refactor diagnostics to focus on Writers

This commit alters the diagnostic emission machinery to be focused around a
Writer for emitting errors. This allows it to not hard-code emission of errors
to stderr (useful for other applications).
auto merge of #12607 : alexcrichton/rust/io++, r=brson

This lowers the #[allow(missing_doc)] directive into some of the lower modules
which are less mature. Most I/O modules now require comprehensive documentation.
std: Remove lots of allocations from log settings

Most of these are unnecessary because we're only looking at static strings. This
also moves to Vec in a few places instead of ~[T].

This didn't end up getting much of a code size win (update_log_settings is the
third largest function in the executables I'm looking at), but this seems like a
generally nice improvement regardless.
std: Avoid using "{:?}" in format strings

This removes all usage of Poly in format strings from libstd. This doesn't
prevent more future strings from coming in, but it at least removes the ones for
now.