libstd: improve os::args() doc
Guide: add a pointer to play.rust-lang.org and explain how to run the code examples.
Reference: Add missing third dot of range
librustrt: check for mips+linux config in stack_overflow
New guide: error handling
Feature gate non-ASCII lifetime identifiers

Fixes #19069.
deriving: error out when used on a non-type

Besides being more helpful, this gives us the flexibility to later define
a meaning for something like

    #[deriving(...)]
    mod bar { ... }
Error handling guide
Switch to an independent enum for `Lit*` subtokens.
Update src/grammar for language changes.
Update makefiles to ensure src/grammar/verify.rs is built.

It's not run, but this ensures that the code at least doesn't go out of
date.
std: Stabilize std::fmt

This commit applies the stabilization of std::fmt as outlined in [RFC 380][rfc].
There are a number of breaking changes as a part of this commit which will need
to be handled to migrated old code:

* A number of formatting traits have been removed: String, Bool, Char, Unsigned,
  Signed, and Float. It is recommended to instead use Show wherever possible or
  to use adaptor structs to implement other methods of formatting.

* The format specifier for Boolean has changed from `t` to `b`.

* The enum `FormatError` has been renamed to `Error` as well as becoming a unit
  struct instead of an enum. The `WriteError` variant no longer exists.

* The `format_args_method!` macro has been removed with no replacement. Alter
  code to use the `format_args!` macro instead.

* The public fields of a `Formatter` have become read-only with no replacement.
  Use a new formatting string to alter the formatting flags in combination with
  the `write!` macro. The fields can be accessed through accessor methods on the
  `Formatter` structure.

Other than these breaking changes, the contents of std::fmt should now also all
contain stability markers. Most of them are still #[unstable] or #[experimental]

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0380-stabilize-std-fmt.md
[breaking-change]

Closes #18904
iOS: fixed broken build after disallowed coercions
Refactor QPath to take an ast::TraitRef
Ensure that the type parameters passed to methods outlive the call expression. Fixes #18899.
Update libcollections tests to pass the new type rules. They used to return a pointer to the value they were modifying, but this should not have been legal, since that pointer would have to outlive the closure, and the closure continues to modify the value during the execution. This return value was just passed to `black_box` so as to convince llvm that the value was live, so rather than returning a pointer, modify to just call `black_box` directly inside the fn.
Parse and store suffixes on literals.

This adds an optional suffix at the end of a literal token:
`"foo"bar`. An actual use of a suffix in a expression (or other literal
that the compiler reads) is rejected in the parser.

This doesn't switch the handling of numbers to this system, and doesn't
outlaw illegal suffixes for them yet.
Switch numeric suffix parsing to use the new system.

This moves errors and all handling of numeric suffixes into the parser
rather than the lexer.
Adjust Antlr4 lexer to include suffixes.

This makes the formal lexical grammar (more closely) reflect the one
implemented by the compiler.
Update documentation for literal suffixes.

This changes the stated grammar of literals to move all suffixes into
the generic literal production.