librustc: Don't ICE with type when name only contain underscores.
lint: Improve camel case suggestion when empty.
doc: remove trailing shell prompts

because eyesore
Adopting FFI changes for iOS
Use the slice repr for ~[T]
Use temp vars for implicit coercion to ^[T]
DST coercions and DST structs

[breaking-change]

1. The internal layout for traits has changed from (vtable, data) to (data, vtable). If you were relying on this in unsafe transmutes, you might get some very weird and apparently unrelated errors. You should not be doing this! Prefer not to do this at all, but if you must, you should use raw::TraitObject rather than hardcoding rustc's internal representation into your code.

2. The minimal type of reference-to-vec-literals (e.g., `&[1, 2, 3]`) is now a fixed size vec (e.g., `&[int, ..3]`) where it used to be an unsized vec (e.g., `&[int]`). If you want the unszied type, you must explicitly give the type (e.g., `let x: &[_] = &[1, 2, 3]`). Note in particular where multiple blocks must have the same type (e.g., if and else clauses, vec elements), the compiler will not coerce to the unsized type without a hint. E.g., `[&[1], &[1, 2]]` used to be a valid expression of type '[&[int]]'. It no longer type checks since the first element now has type `&[int, ..1]` and the second has type &[int, ..2]` which are incompatible.

3. The type of blocks (including functions) must be coercible to the expected type (used to be a subtype). Mostly this makes things more flexible and not less (in particular, in the case of coercing function bodies to the return type). However, in some rare cases, this is less flexible. TBH, I'm not exactly sure of the exact effects. I think the change causes us to resolve inferred type variables slightly earlier which might make us slightly more restrictive. Possibly it only affects blocks with unreachable code. E.g., `if ... { fail!(); "Hello" }` used to type check, it no longer does. The fix is to add a semicolon after the string.
Rebasing changes
Optimise a particularly clown shoes example of DST codegen
auto merge of #14397 : nick29581/rust/coerce, r=pnkfelix

DST coercions and DST fields in structs

The commits are not quite stand alone, I should probably squash them together before landing. In particular if you review the individual commits, then you'll see some scrappy stuff that gets fixed in later commits. But reading the commits in order might be easier to get an overall idea of what is going on.

The first commit includes putting back time zone into our time library - @pcwalton removed that as part of his de-~str'ing, but I had already converted it to use StrBuf, so we may as well leave it in. Update: no longer, this is removed in a later commit.
auto merge of #16720 : tshepang/rust/trailing-prompt, r=alexcrichton

because eyesore
auto merge of #16742 : vhbit/rust/ios-ffi-fix, r=alexcrichton
auto merge of #16704 : flugsio/rust/fix-rustc-ice-lint-underscores-only, r=brson

Fix for type identifiers with only underscores (two or more), I assume they doesn't count as camel case.

```rust
type __ = int;

fn main() {
}
```

```
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
task 'rustc' failed at 'index out of bounds: the len is 0 but the index is 0', /home/rustbuild/src/rust-buildbot/slave/nightly-linux/build/src/librustc/lib.rs:1

stack backtrace:
   1: 0xb603f5d0 - rt::backtrace::imp::write::ha55f265f6626471dmxr
   2: 0xb6042620 - failure::on_fail::h4d2c6d42b67e94803Sr
   3: 0xb640a180 - unwind::begin_unwind_inner::h484879fa7cc3611fZhe
   4: 0xb6409e50 - unwind::begin_unwind_fmt::hd14e5c64bc9006capfe
   5: 0xb6409df0 - rust_begin_unwind
   6: 0xb6454580 - failure::begin_unwind::h9ab1fc5753bd08f3YDk
   7: 0xb6458cb0 - failure::fail_bounds_check::h88167bad36865909aCk
   8: 0xb6f685d0 - lint::builtin::NonCamelCaseTypes.LintPass::check_item::check_case::he854eeffd105cb0f40E
   9: 0xb6f68050 - lint::builtin::NonCamelCaseTypes.LintPass::check_item::hc35b45d248e41cd43XE
  10: 0xb6f7b760 - lint::context::Context<'a>.Visitor<(*>::visit_item::closure.139262
  11: 0xb6f79510 - lint::context::Context<'a>::with_lint_attrs::hb9efe321fa321ce6spG
  12: 0xb6f81d30 - lint::context::Context<'a>.Visitor<(*>::visit_mod::he4593c831936b308ZMG
  13: 0xb6f8f2f0 - lint::context::check_crate::closure.139319
  14: 0xb6f79510 - lint::context::Context<'a>::with_lint_attrs::hb9efe321fa321ce6spG
  15: 0xb6efda70 - lint::context::check_crate::ha9e64328726b9579q1G
  16: 0xb6efda20 - driver::driver::phase_3_run_analysis_passes::closure.136263
  17: 0xb659d640 - util::common::time::h2837683151147173214
  18: 0xb6e7d130 - driver::driver::phase_3_run_analysis_passes::h7079eff53afc4de3Jfz
  19: 0xb6e783f0 - driver::driver::compile_input::h0ec84a550e24779cP1y
  20: 0xb6f26250 - driver::run_compiler::h7e7c01ecbfd0ad87JzC
  21: 0xb6f26150 - driver::main_args::closure.137215
  22: 0xb6f380d0 - task::TaskBuilder<S>::try_future::closure.138376
  23: 0xb6f37ec0 - task::TaskBuilder<S>::spawn_internal::closure.138353
  24: 0xb774bdd0 - task::spawn_opts::closure.8325
  25: 0xb6409c10 - unwind::try::try_fn::h91f00772748cf73eD8d
  26: 0xb6468ae0 - rust_try_inner
  27: 0xb6468aa0 - rust_try
  28: 0xb6407880 - unwind::try::h78a4fc0e85c326aef6d
  29: 0xb6407640 - task::Task::run::hb6f2d9484116e3d8xcd
  30: 0xb774bba0 - task::spawn_opts::closure.8271
  31: 0xb6409350 - thread::thread_start::h8c02fef9f651da5cjBd
  32: 0xb5ed3fc0 - start_thread
  33: 0xb62e8a32 - __clone
  34:        0x0 - <unknown>
```