This adds a pretty contrived example of the usage of fmt::Error. I am
very open to suggestions for a better one.

I have also highlighted the fmt::Error vs std::error::Error.

r? @steveklabnik

fn Path::new<S: AsRef ...>(s: &S) -> &Path

Signed-off-by: NODA, Kai <[email protected]>

After rust-lang#43252 is merged, building stage0 libcore with -i (--incremental)
flag will cause 17 "Quasi-quoting might make incremental compilation very
inefficient: NtExpr(..)" warnings, as in rust-lang#40946.

Fixing the warning in rust-lang#40946 will take 12 weeks from now to make into the
next stage0, so it is quicker to workaround it in libcore instead.

Changed wording of docs on `std::time::Duration` for better clarity
w.r.t. the contents of the type and the purpose of its methods.

Reorder the job matrix to take advantage of the order how Travis CI starts
them in rust-lang/rust. Plus other refactoring of `.travis.yml`.

1. Move the `$ALLOW_PR` image to the top, so users' PRs will start testing
   immediately. Previously the `$ALLOW_PR` image starts 6 minutes after the
   build was scheduled.

2. Move the slow macOS images near the top, so they share more time with
   the rest of the faster Linux builds, which should shorten total test
   time (actually not much, about 7 minutes at most if this change does
   work).

3. Merged the `install` section of both Linux and macOS to make the `env:`
   section a bit shorter, and enable change 4 below.

4. Do not download or install anything if `$SKIP_BUILD == true`, which
   further reduces chance of spurious failure in the PR-CI stage (avoid the
   red cross appearing even if CI passed).

I seem to have been a little too tired when I fixed up the container scripts,
applying the wrong flag!

Update docs on Error struct. rust-lang#29355

This adds a pretty contrived example of the usage of fmt::Error. I am
very open to suggestions for a better one.

I have also highlighted the fmt::Error vs std::error::Error.

r? @steveklabnik

Update merge queue link in CONTRIBUTING.md

…excrichton

Change Travis CI job order.

Reorder the job matrix to take advantage of the order how Travis CI starts them in rust-lang/rust. Plus other refactoring of `.travis.yml`.

1. Move the `$ALLOW_PR` image to the top, so pull requests will start testing as immediately after the build is started. Previously the `$ALLOW_PR` image starts 6 minutes after the build was scheduled.

2. Move the slow macOS images near the top, so they share more time with the rest of the faster Linux builds, which should shorten total test time (actually not much, about 7 minutes at most if this change does work).

3. Merged the `install` section of both Linux and macOS to make the `env:` section a bit shorter, and enable change 4 below.

4. Do not download or install anything if `$SKIP_BUILD == true`, which further reduces chance of spurious failure in the PR-CI stage (avoid the red cross appearing even if CI passed).

(IMO `$SKIP_BUILD` should not even exist: those irrelevant jobs should not start at all, but that would require travis-ci/travis-ci#2778 which has been rejected)

…mulacrum

libstd: remove redundant & from &Path::new(...)

```rust
fn Path::new<S: AsRef ...>(s: &S) -> &Path
```

* https://doc.rust-lang.org/std/path/struct.Path.html#method.new

…n-rustbuild, r=alexcrichton

Workaround "Quasi-quoting is inefficient" warning in incremental rustbuild introduced in rust-lang#43252.

After rust-lang#43252 is merged, building stage0 libcore with `-i` (`--incremental`) flag will cause 17 "Quasi-quoting might make incremental compilation very inefficient: NtExpr(..)" warnings, as in rust-lang#40946.

```
warning: Quasi-quoting might make incremental compilation very inefficient: NtExpr(..)
   --> src/libcore/default.rs:133:21
    |
133 |             #[doc = $doc]
    |                     ^^^^
...
139 | default_impl! { (), (), "Returns the default value of `()`" }
    | ------------------------------------------------------------- in this macro invocation
(× 17)
```

True fix for rust-lang#40946 will take at least 12 weeks from now to make into the next stage0, so it is quicker to workaround it in libcore instead.

cc @vbrandl @jseyfried

…, r=aturon

`std::time::Duration`: improve _precision_ of terminology in docs

Changed wording of docs on `std::time::Duration` for better clarity w.r.t. the contents of the type and the purpose of its methods.  (Specifically, removed the use of the word "precision" to describe the fractional part of the `Duration` because "precision" is more properly used to describe how _precise_ a value is, i.e. its granularity in this case.)

redox: handle multiple paths in PATH

Fix erroneous reference to Arc instead of Rc in rc::Weak documentation

The docs for `rc::Weak` refer to `Arc` in one place, where they should obviously be referring to `Rc`; presumably this was erroneously copied over from the `arc::Weak` docs.

powerpc: Ignore the stack-probes test

One little step further to have the test working fine on power8 :)

travis: Switch `curl -s` to `curl -f`

I seem to have been a little too tired when I fixed up the container scripts,
applying the wrong flag!

…alexcrichton

float_bits_conv made it into 1.20

It seems that my PR to stabilize the `float_bits_conv` feature got merged before beta branched, which means I'm lucky, and the stabilization makes it into Rust 1.20. As it was against my expectations, the version number has to be corrected from 1.21 to 1.20.

Please also apply this PR to the beta branch.