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 #21402
cc #15294

Simplify BTree's iterators, too.

Conflicts:
	src/libserialize/serialize.rs

This is a breaking change. To fix it you should pass the VecMap by value
instead of by reference.

[breaking-change]

Signed-off-by: NPeter Atashian <retep998@gmail.com>

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

'x in y' is more Pythonic and faster than 'y.find(x) != -1'.

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

Only print NOTE warnings if the 'TRAVIS' environment variable has not
been set. Addresses #21322.

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.

From std::markers to std::marker.

Having both "Right now" and "at the moment" in the same statement is redundant.

It got accidentially reverted in 44440e5c.

The reference should be `x`, not `FOO` itself.