Stebalien/rust forked from rust-lang/rust

This trait can be used to avoid the overhead of a fuse wrapper when an iterator
is already well-behaved.

Conforming to: RFC 1581
Closes: rust-lang#35602

…r=nikomatsakis

Move 'doesn't live long enough' errors to labels

This patch moves the "doesn't live long enough" region-style errors to instead use labels.

An example follows.

Before:

```
error: `x` does not live long enough
  --> src/test/compile-fail/send-is-not-static-ensures-scoping.rs:26:18
   |
26 |         let y = &x;
   |                  ^
   |
note: reference must be valid for the block at 23:10...
  --> src/test/compile-fail/send-is-not-static-ensures-scoping.rs:23:11
   |
23 | fn main() {
   |           ^
note: ...but borrowed value is only valid for the block suffix following statement 0 at 25:18
  --> src/test/compile-fail/send-is-not-static-ensures-scoping.rs:25:19
   |
25 |         let x = 1;
   |                   ^
```

After:

```
error: `x` does not live long enough
  --> src/test/compile-fail/send-is-not-static-ensures-scoping.rs:26:18
   |
26 |         let y = &x;
   |                  ^ does not live long enough
...
32 |     };
   |     - borrowed value only valid until here
...
35 | }
   | - borrowed value must be valid until here
```

r? @nikomatsakis

Rollup of 12 pull requests

- Successful merges: rust-lang#35346, rust-lang#35734, rust-lang#35739, rust-lang#35740, rust-lang#35742, rust-lang#35744, rust-lang#35749, rust-lang#35750, rust-lang#35751, rust-lang#35756, rust-lang#35766, rust-lang#35768
- Failed merges:

…urner

Updated test for E0221

As a part of issue rust-lang#35233
?r @GuillaumeGomez

…ndturner

Add new error code tests

r? @jonathandturner

…rner

Additional span info for E0053

Part of rust-lang#35233.
Fixes rust-lang#35212.

r? @jonathandturner

…omez

New output for E0407

Issue rust-lang#35697 as a part of rust-lang#35233.
r? @GuillaumeGomez

Fix the invalidation of the MIR early exit cache

~~The rust-lang#34307 introduced a cache for early exits in order to help with O(n*m) explosion of cleanup blocks but the cache is invalidated incorrectly and I can’t seem to figure out why (caching is hard!)~~

~~Remove the cache for now to fix the immediate correctness issue and worry about the performance later.~~

Cache invalidation got fixed.

Fixes rust-lang#35737

r? @nikomatsakis

Add 'make help' for rustbuild

It is still advertised by the configure script.

…ndturner

Fixes issue rust-lang#11004

Fixes rust-lang#11004.

r? @jonathandturner

…dturner

Update E0009 to new format

Part of rust-lang#35233
Fixes rust-lang#35193

r? @jonathandturner

…omatsakis

Update minimum CMake version in README

The minimum got bumped in the LLVM upgrade of rust-lang#34743.

Update LLVM to include 4 backported commits by @majnemer.

Partial fix for rust-lang#35662, should help at least loops on small arrays.

Nominated for backporting into the new beta (not the one that's being released as stable this week).

r? @alexcrichton

…t, r=jonathandturner

E0403 update error format

Fixes rust-lang#35696

Part of rust-lang#35233

r? @jonathandturner

Also did the bonus for this one.

add mips-uclibc targets

These targets cover OpenWRT 15.05 devices, which use the soft float ABI
and the uclibc library. None of the other built-in mips targets covered
those devices (mips-gnu is hard float and glibc-based, mips-musl is
musl-based).

With this commit one can now build std for these devices using these
commands:

```
$ configure --enable-rustbuild --target=mips-unknown-linux-uclibc
$ make
```

cc rust-lang#35673

---

r? @alexcrichton
cc @felixalias This is the target the rust-tessel project should be using.
Note that the libc crate doesn't support the uclibc library and will have to be updated. We are lucky that uclibc and glibc are somewhat similar and one can build std and even run the libc-test test suite with the current, unmodified libc. About that last part, I tried to run the libc-test and got a bunch of compile errors. I don't intend to fix them but I'll post some instruction about how to run libc-test in the rust-lang/libc issue tracker.

…handturner

Update compiler error 0093 to use new error format

Addresses rust-lang#35230, Part of the rust-lang#35233 meta bug

r? @jonathandturner

… r=nikomatsakis

Replace macro backtraces with labeled local uses

This PR (which builds on rust-lang#35688) follows from the conversations on how best to [handle the macro backtraces](https://internals.rust-lang.org/t/improving-macro-errors/3809).  The feeling there was that there were two different "groups" of users.

The first group, the macro users, rarely (and likely never) want to see the macro backtrace.  This is often more confusing to users as it will be talking about code they didn't write.

The second group, the macro writers, are trying to debug a macro.  They'll want to see something of the backtrace so that they can see where it's going wrong and what the steps were to get there.

For the first group, it seems clear that we don't want to show *any* macro backtrace.  For the second group, we want to show enough to help the macro writer.

This PR uses a heuristic.  It will only show any backtrace steps if they are in the same crate that is being compiled.  This keeps errors in foreign crates from showing to users that didn't need them.

Additionally, in asking around I repeated heard that the middle steps of the backtrace are rarely, if ever, used in practice.  This PR takes and applies this knowledge.  Now, instead of a full backtrace, the user is given the error underline inside of a local macro as well as the use site as a secondary label.  This effectively means seeing the root of the error and the top of the backtrace, eliding the middle steps.

Rather than being the "perfect solution", this PR opts to take an incremental step towards a better experience.  Likely it would help to have additional macro debugging tools, as they could be much more verbose than we'd likely want to use in the error messages themselves.

Some examples follow.

**Example 1**

Before:

<img width="1275" alt="screen shot 2016-08-15 at 4 13 18 pm" src="https://cloud.githubusercontent.com/assets/547158/17682828/3948cea2-6303-11e6-93b4-b567e9d62848.png">

After:

<img width="596" alt="screen shot 2016-08-15 at 4 13 03 pm" src="https://cloud.githubusercontent.com/assets/547158/17682832/3d670d8c-6303-11e6-9bdc-f30a30bf11ac.png">

**Example 2**

Before:

<img width="918" alt="screen shot 2016-08-15 at 4 14 35 pm" src="https://cloud.githubusercontent.com/assets/547158/17682870/722225de-6303-11e6-9175-336a3f7ce308.png">

After:

<img width="483" alt="screen shot 2016-08-15 at 4 15 01 pm" src="https://cloud.githubusercontent.com/assets/547158/17682872/7582cf6c-6303-11e6-9235-f67960f6bd4c.png">

1.11 changelog

[Rendered](https://github.com/brson/rust/blob/9863afe029092d421c9a3daafd6b7a718d53f1cf/RELEASES.md)

r? @steveklabnik

It's too late to get this into the actual release, but still needs to be backported to 1.12 beta.

As a part of issue rust-lang#35233
?r @GuillaumeGomez

Fixes rust-lang#35737

Issue rust-lang#35697 as a part of rust-lang#35233.
r? @jonathandturner