README example doesn't work

[alexwlchan]

I took the first example from the README, and tried to run it with the current stable compiler:

$ rustc --version
rustc 1.17.0 (56124baa9 2017-04-24)

These are my files:

# Cargo.toml
[package]
name = "regex-example"
version = "0.1.0"
authors = ["Alex Chan <alex@alexwlchan.net>"]

[dependencies]
regex = "0.2"

// src/main.rs
extern crate regex;

use regex::Regex;

fn main() {
    let re = Regex::new(r"(?x)
(?P<year>\d{4})  # the year
-
(?P<month>\d{2}) # the month
-
(?P<day>\d{2})   # the day
").unwrap();
    let caps = re.captures("2010-03-14").unwrap();

    assert_eq!("2010", caps["year"]);
    assert_eq!("03", caps["month"]);
    assert_eq!("14", caps["day"]);

If I take these two files in a new project and run cargo run, I get an error:

$ cargo run
    Updating registry `https://github.com/rust-lang/crates.io-index`
 Downloading aho-corasick v0.6.3
 Downloading libc v0.2.22
   Compiling regex-syntax v0.4.0
   Compiling void v1.0.2
   Compiling libc v0.2.22
   Compiling utf8-ranges v1.0.0
   Compiling unreachable v0.1.1
   Compiling thread-id v3.0.0
   Compiling memchr v1.0.1
   Compiling thread_local v0.3.3
   Compiling aho-corasick v0.6.3
   Compiling regex v0.2.1
   Compiling regex-example v0.1.0 (file:///private/var/folders/0d/p_z4b6f90g1gc8h9y87w0td80000gn/T/tmp.l0If1jQ6/regex-example)
error[E0277]: the trait bound `&str: std::cmp::PartialEq<str>` is not satisfied
  --> src/main.rs:15:5
   |
15 |     assert_eq!("2010", caps["year"]);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::cmp::PartialEq<str>` is not implemented for `&str`
   |
   = help: the following implementations were found:
             <str as std::cmp::PartialEq>
             <str as std::cmp::PartialEq<std::ffi::OsString>>
             <str as std::cmp::PartialEq<std::ffi::OsStr>>
             <str as std::cmp::PartialEq<std::string::String>>
           and 3 others
   = note: this error originates in a macro outside of the current crate

error[E0277]: the trait bound `&str: std::cmp::PartialEq<str>` is not satisfied
  --> src/main.rs:16:5
   |
16 |     assert_eq!("03", caps["month"]);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::cmp::PartialEq<str>` is not implemented for `&str`
   |
   = help: the following implementations were found:
             <str as std::cmp::PartialEq>
             <str as std::cmp::PartialEq<std::ffi::OsString>>
             <str as std::cmp::PartialEq<std::ffi::OsStr>>
             <str as std::cmp::PartialEq<std::string::String>>
           and 3 others
   = note: this error originates in a macro outside of the current crate

error[E0277]: the trait bound `&str: std::cmp::PartialEq<str>` is not satisfied
  --> src/main.rs:17:5
   |
17 |     assert_eq!("14", caps["day"]);
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::cmp::PartialEq<str>` is not implemented for `&str`
   |
   = help: the following implementations were found:
             <str as std::cmp::PartialEq>
             <str as std::cmp::PartialEq<std::ffi::OsString>>
             <str as std::cmp::PartialEq<std::ffi::OsStr>>
             <str as std::cmp::PartialEq<std::string::String>>
           and 3 others
   = note: this error originates in a macro outside of the current crate

error: aborting due to 3 previous errors

error: Could not compile `regex-example`.

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