Multiple people have asked me if this is a reference to Hacker News, and
I _certainly_ don't want to give them that impression.

Closes #21350

The script is intended as a tool for doing every sort of verifications amenable to Rustdoc's HTML output. For example, link checkers would go to this script. It already parses HTML into a document tree form (with a slight caveat), so future tests can make use of it.

As an example, relevant `rustdoc-*` run-make tests have been updated to use `htmldocck.py` and got their `verify.sh` removed. In the future they may go to a dedicated directory with htmldocck running by default. The detailed explanation of test scripts is provided as a docstring of htmldocck.

cc #19723

cc #19872, this may help give some insight

These two attributes are used to change the entry point into a Rust program, but
for now they're being put behind feature gates until we have a chance to think
about them a little more. The #[start] attribute specifically may have its
signature changed.

This is a breaking change to due the usage of these attributes generating errors
by default now. If your crate is using these attributes, add this to your crate
root:

    #![feature(start)] // if you're using the #[start] attribute
    #![feature(main)]  // if you're using the #[main] attribute

cc #20064

This commit aims to stabilize the `TypeId` abstraction by moving it out of the
`intrinsics` module into the `any` module of the standard library. Specifically,

* `TypeId` is now defined at `std::any::TypeId`
* `TypeId::hash` has been removed in favor of an implementation of `Hash`.

This commit also performs a final pass over the `any` module, confirming the
following:

* `Any::get_type_id` remains unstable as *usage* of the `Any` trait will likely
  never require this, and the `Any` trait does not need to be implemented for
  any other types. As a result, this implementation detail can remain unstable
  until associated statics are implemented.
* `Any::downcast_ref` is now stable
* `Any::downcast_mut` is now stable
* `BoxAny` remains unstable. While a direct impl on `Box<Any>` is allowed today
  it does not allow downcasting of trait objects like `Box<Any + Send>` (those
  returned from `Thread::join`). This is covered by #18737.
* `BoxAny::downcast` is now stable.

importing object type string key maps is still supported
writing them should be explicit, and can be done as follows

```rust
let some_tree_map : TreeMap<String, Json> = ...;
Json::Object(some_tree_map).to_writer(&mut writer);
```

related to #8335, #9028, #9142

Closes #21033. The new strategy for parsing a field pattern is to look 1 token ahead and if it's a colon, parse as "fieldname: pat", otherwise parse the shorthand form "(box) (ref) (mut) fieldname)". The previous strategy was to parse "(ref) (mut) fieldname" then if we encounter a colon, throw an error if either "ref" or "mut" were encountered. 

Part of collections reform v1, #18424
Also, iteration is simplified:
```
before
test btree::map::bench::iter_1000                          ... bench:     17177 ns/iter (+/- 6302)
test btree::map::bench::iter_100000                        ... bench:   1735731 ns/iter (+/- 23908)
test btree::map::bench::iter_20                            ... bench:       386 ns/iter (+/- 148)
after
test btree::map::bench::iter_1000                          ... bench:     15777 ns/iter (+/- 346)
test btree::map::bench::iter_100000                        ... bench:   1602604 ns/iter (+/- 73629)
test btree::map::bench::iter_20                            ... bench:       339 ns/iter (+/- 91)
```
cc @gereeter @cgaebel
r? @Gankro

Simplify BTree's iterators, too.

This commit modifies resolve to prevent conflicts with typedef names in the same
method that conflits are prevented with enum names. This is a breaking change
due to the differing semantics in resolve, and any errors generated on behalf of
this change require that a conflicting typedef, module, or structure to be
renamed so they do not conflict.

[breaking-change]
Closes #6936

Conflicts:
	src/libserialize/serialize.rs

LLVM gets overwhelmed when presented with a zeroinitializer for a large
type. In unoptimised builds, it generates a long sequence of stores to
memory. In optmised builds, it manages to generate a standard memset of
zero values, but takes a long time doing so.

Call out to the `llvm.memset` function to zero out the memory instead.

Fixes #21264

This is a [breaking-change] since `std::dynamic_lib::dl` is now
private.

When `LoadLibraryW()` fails, original code called `errno()` to get error
code.  However, there was local allocation of `Vec` before
`LoadLibraryW()`, and it drops before `errno()`, and the drop
(deallocation) changed `errno`! Therefore `dynamic_lib::open()` thought
it always succeeded.
This commit fixes the issue.

This commit also sets Windows error mode during `LoadLibrary()` to
prevent "dll load failed" dialog.

This avoids having ast::Ty nodes which have no counterpart in the source.

This commit aims to stabilize the `TypeId` abstraction by moving it out of the
`intrinsics` module into the `any` module of the standard library. Specifically,

* `TypeId` is now defined at `std::any::TypeId`
* `TypeId::hash` has been removed in favor of an implementation of `Hash`.

This commit also performs a final pass over the `any` module, confirming the
following:

* `Any::get_type_id` remains unstable as *usage* of the `Any` trait will likely
  never require this, and the `Any` trait does not need to be implemented for
  any other types. As a result, this implementation detail can remain unstable
  until associated statics are implemented.
* `Any::downcast_ref` is now stable
* `Any::downcast_mut` is now stable
* `BoxAny` remains unstable. While a direct impl on `Box<Any>` is allowed today
  it does not allow downcasting of trait objects like `Box<Any + Send>` (those
  returned from `Thread::join`). This is covered by #18737.
* `BoxAny::downcast` is now stable.

This commit modifies resolve to prevent conflicts with typedef names in the same
method that conflits are prevented with enum names. This is a breaking change
due to the differing semantics in resolve, and any errors generated on behalf of
this change require that a conflicting typedef, module, or structure to be
renamed so they do not conflict.

[breaking-change]
Closes #6936

Helps reduce some rightward drift

This patch fixes IP_ADD_MEMBERSHIP problem described here: https://github.com/rust-lang/rust/issues/20381

I've tested on my ProbeR project, everything seems ok.

LLVM gets overwhelmed when presented with a zeroinitializer for a large
type. In unoptimised builds, it generates a long sequence of stores to
memory. In optmised builds, it manages to generate a standard memset of
zero values, but takes a long time doing so.

Call out to the `llvm.memset` function to zero out the memory instead.

cc #19872, this may help give some insight

Closes #21350

This is a [breaking-change] since `std::dynamic_lib::dl` is now
private.

When `LoadLibraryW()` fails, original code called `errno()` to get error
code.  However, there was local allocation of `Vec` before
`LoadLibraryW()`, and it drops before `errno()`, and the drop
(deallocation) changed `errno`! Therefore `dynamic_lib::open()` thought
it always succeeded.
This commit fixes the issue.

This commit also sets Windows error mode during `LoadLibrary()` to
prevent "dll load failed" dialog.

 * add `Token::AndAnd` (double borrow)
 * add `Token::DotDot` (range notation)
 * remove `Token::Pound` and `Token::At`

This fixes a syntax error when parsing `fn f() -> RangeTo<i32> { return ..1; }`.

Also, remove `fn_expr_lookahead`.
It's from the `fn~` days and seems to no longer be necessary.

Follow up to #21008.

r? @nikomatsakis 

This fixes the issues mentioned in https://github.com/rust-lang/rust/pull/21236, as well as the one https://github.com/rust-lang/rust/issues/21230 where `CFG_BOOTSTRAP_KEY` was being set to simply 'N'. It changes the build such that `RUSTC_BOOTSTRAP_KEY` is only exported on -beta and -stable, so that the behavior of the -dev, -nightly, and snapshot compilers is the same everywhere.

Haven't run it completely through 'make check' yet, but the I have verified that the aforementioned issues are fixed.

r? @alexcrichton cc @EddyB

auto merge of #21330 : JeffBelgum/rust/collections-reform-issue-19986-add-append-and-split-off, r=Gankro

Please review carefully. Contains unsafe and is my first commit to Rust.

Uses ptr::copy_nonoverlapping_memory. Attempts to handle zero-size types correctly.