Log Message:
Update to 1.31.0

Changelog:
Version 1.31.0 (2018-12-06)
Language

    This version marks the release of the 2018 edition of Rust.
    New lifetime elision rules now allow for eliding lifetimes in functions and \ 
impl headers. E.g. impl<'a> Reader for BufReader<'a> {} can now be \ 
impl Reader for BufReader<'_> {}. Lifetimes are still required to be \ 
defined in structs.
    You can now define and use const functions. These are currently a strict \ 
minimal subset of the const fn RFC. Refer to the language reference for what \ 
exactly is available.
    You can now use tool lints, which allow you to scope lints from external \ 
tools using attributes. E.g. #[allow(clippy::filter_map)].
    #[no_mangle] and #[export_name] attributes can now be located anywhere in a \ 
crate, not just in exported functions.
    You can now use parentheses in pattern matches.

Compiler

    Updated musl to 1.1.20

Libraries

    You can now convert num::NonZero* types to their raw equivalvents using the \ 
From trait. E.g. u8 now implements From<NonZeroU8>.
    You can now convert a &Option<T> into Option<&T> and \ 
&mut Option<T> into Option<&mut T> using the From trait.
    You can now multiply (*) a time::Duration by a u32.

Stabilized APIs

    slice::align_to
    sl

    ice::align_to_mut
    slice::chunks_exact
    slice::chunks_exact_mut
    slice::rchunks
    slice::rchunks_mut
    slice::rchunks_exact
    slice::rchunks_exact_mut
    Option::replace

Cargo

    Cargo will now download crates in parallel using HTTP/2.
    You can now rename packages in your Cargo.toml We have a guide on how to use \ 
the package key in your dependencies.