Constants with values that depend on generic parameters or `Self` cause
ICEs in `check_const`, and are not yet accepted via RFC, so we need to
throw a proper error in these cases.

- Successful merges: #25465, #25469, #25472, #25474, #25476, #25484, #25490, #25493, #25503, #25506, #25508, #25510, #25516, #25522
- Failed merges: 

This iterator was mistakenly not reexported at the top level, preventing
actually naming the type!

Closes #25519

No need for `&b"foo"[..]` to make a CString, `"foo"` will do.

The same example for ``reverse`` were in the ``reserve_exact``'s example.

The current version of the example won't compile due to unstable features.
This is an attempt to fix that, at the cost of slightly more verbose code.

Using rust 1.0.0 (a59de37e).

It might be obvious, but I'm not well versed with rust, so feedback is very welcome.

Newcomers to Rust need to learn the distinctinion between `&str` and
`String`, so additonally having `string` in an example risks confusion.

Rust is out of beta 🎉 

r? @steveklabnik

In "The Rust Language FAQ", some of the links to example projects/modules written in Rust are dead links. This PR updates them.

Closes #18173

This PR fixes two little typos in the Dining Philosophers example.

Also, there are two style points that may have been oversights but may have been deliberate, so I'll just bring them up here:

1) In the last paragraph, you say

> You’ll notice we can introduce a new binding to `table` here, and it will shadow the old one. This is often used so that you don’t need to come up with two unique names.

You already said something similar to this in the Guessing Game, but maybe you intended for this example to be independent of that one.

2) In "Rust Inside Other Languages," you introduce the idea of the "global interpreter lock" and then refer to it as the GIL a few paragraphs later without explicitly stating that GIL == global interpreter lock. It's reasonable to expect readers to make the connection, but maybe that's not what you intended.

Excellent work on the examples! Congrats on 1.0!

r? @steveklabnik

Just detected it while reading.

r? @steveklabnik 

This iterator was mistakenly not reexported at the top level, preventing
actually naming the type!

Closes #25519

No need for `&b"foo"[..]` to make a CString, `"foo"` will do.

This allows compiling entire crates from memory or preprocessing source files before they are tokenized.

Minor API refactoring included, which is a [breaking-change] for libsyntax users:
* `ParseSess::{next_node_id, reserve_node_ids}` moved to rustc's `Session`
* `new_parse_sess` -> `ParseSess::new`
* `new_parse_sess_special_handler` -> `ParseSess::with_span_handler`
* `mk_span_handler` -> `SpanHandler::new`
* `default_handler` -> `Handler::new`
* `mk_handler` -> `Handler::with_emitter`
* `string_to_filemap(sess source, path)` -> `sess.codemap().new_filemap(path, source)`

The same example for ``reverse`` were in the ``reserve_exact``'s example.

The current version of the example won't compile due to unstable features.
This is an attempt to fix that, at the cost of slightly more verbose code.

Newcomers to Rust need to learn the distinctinion between `&str` and
`String`, so additonally having `string` in an example risks confusion.

fix #24968
report more friendly error message for Self when fn args
copy from https://github.com/rust-lang/rust/pull/25096
r? @nrc  @arielb1

Using regular pointer arithmetic to iterate collections of zero-sized types
doesn't work, because we'd get the same pointer all the time. Our
current solution is to convert the pointer to an integer, add an offset
and then convert back, but this inhibits certain optimizations.

What we should do instead is to convert the pointer to one that points
to an i8\*, and then use a LLVM GEP instructions without the inbounds
flag to perform the pointer arithmetic. This allows to generate pointers
that point outside allocated objects without causing UB (as long as you
don't dereference them), and it wraps around using two's complement,
i.e. it behaves exactly like the wrapping_* operations we're currently
using, with the added benefit of LLVM being able to better optimize the
resulting IR.

Helps prevent mixed content warnings if accessing docs over HTTPS.

Closes #25459

Fixes #25489

Most of `Rc`’s trait implementations were DST-ified in #24619, but not these ones.

🎉 🎉 🎉

Permit token trees, identifiers, and blocks to be following by sequences.

Fixes #25436.

r? @pnkfelix 

Closes #25468.