Instead of

```
error: no method named `src_addr` found for type `&wire::ipv4::Repr` in the current scope
   --> src/wire/ipv4.rs:409:34
    |
409 |         packet.set_src_addr(self.src_addr());
    |                                  ^^^^^^^^
    |
note: did you mean to write `self.src_addr`?
   --> src/wire/ipv4.rs:409:34
    |
409 |         packet.set_src_addr(self.src_addr());
    |                                  ^^^^^^^^
```

present

```
error: no method named `src_addr` found for type `&wire::ipv4::Repr` in the current scope
   --> src/wire/ipv4.rs:409:34
    |
409 |         packet.set_src_addr(self.src_addr());
    |                                  ^^^^^^^^ `src_addr` is a field, not a method
    |
    = help: did you mean to write `self.src_addr` instead of `self.src_addr(...)`?
```

`other` is guaranteed to be less than `2 * len`.

…ce in docs

…lexcrichton

Attempt to cache git modules

Partial resolution of rust-lang#40772, appveyor remains to be done once travis looks like it's working ok.

The approach in this PR is based on the `--reference` flag to `git-clone`/`git-submodule --update` and is a compromise based on the current limitations of the tools we're using.

The ideal would be:
1. have a cached pristine copy of rust-lang/rust master in `$HOME/rustsrc` with all submodules initialised
2. clone the PR branch with `git clone --recurse-submodules --reference $HOME/rustsrc [email protected]:rust-lang/rust.git`

This would (in the nonexistent ideal world) use the pristine copy as an object cache for the top level repo and all submodules, transferring over the network only the changes on the branch. Unfortunately, a) there is no way to manually control the initial clone with travis and b) even if there was, cloned submodules don't use the submodules of the reference as an object cache. So the steps we end up with are:

1. have a cached pristine copy of rust-lang/rust master in `$HOME/rustsrc` with all submodules initialised
2. have a cloned PR branch
3. extract the path of each submodule, and explicitly `git submodule update --init --reference $HOME/rustsrc/$module $module` (i.e. point directly to the location of the pristine submodule repo) for each one

I've also taken some care to make this forward compatible, both for adding and removing submodules.

r? @alexcrichton

Rustdoc: memoize `pub use`-reexported macros so they don't appear twice in docs

Closes rust-lang#39436

Preserves existing behavior for `#[macro_reexport]`. `pub use`'d macros are shown as reexports unless inlined, and also correctly obey `#[doc(hidden)]`.

r? @jseyfried

cc @SergioBenitez

Clarify suggetion for field used as method

Instead of

```rust
error: no method named `src_addr` found for type `&wire::ipv4::Repr` in the current scope
   --> src/wire/ipv4.rs:409:34
    |
409 |         packet.set_src_addr(self.src_addr());
    |                                  ^^^^^^^^
    |
note: did you mean to write `self.src_addr`?
   --> src/wire/ipv4.rs:409:34
    |
409 |         packet.set_src_addr(self.src_addr());
    |                                  ^^^^^^^^
```

present

```rust
error: no method named `src_addr` found for type `&wire::ipv4::Repr` in the current scope
   --> src/wire/ipv4.rs:409:34
    |
409 |         packet.set_src_addr(self.src_addr());
    |                                  ^^^^^^^^ field, not a method
    |
    = help: did you mean to write `self.src_addr` instead of `self.src_addr(...)`?
```

Fix rust-lang#38321.

libcore: fix compilation on 16bit target (MSP430).

Since PR rust-lang#40601 has been merged, libcore no longer compiles on MSP430.
The reason is this code in `break_patterns`:
```rust
 let mut random = len;
 random ^= random << 13;
 random ^= random >> 17;
 random ^= random << 5;
 random &= modulus - 1;
```
It assumes that `len` is at least a 32 bit integer.
As a workaround replace `break_patterns` with an empty function for 16bit targets.

cc @stjepang
cc @alexcrichton

…teveklabnik

Avoid linking to a moved page in rust.html

…=steveklabnik

Linked str in from_utf_unchecked

References rust-lang#29375. Linked `str` in from_utf_unchecked's documentation to the docs for primitive `str`