Rollup of 16 pull requests

.gitmodules

@@ -65,3 +65,6 @@
 [submodule "src/doc/rustc-guide"]
 	path = src/doc/rustc-guide
 	url = https://github.com/rust-lang/rustc-guide.git
+[submodule "src/doc/edition-guide"]
+	path = src/doc/edition-guide
+	url = https://github.com/rust-lang-nursery/edition-guide

Cargo.lock

@@ -201,6 +201,7 @@ dependencies = [
  "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "home 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "ignore 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "im-rc 12.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jobserver 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazycell 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -624,6 +625,15 @@ name = "difference"
 version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "directories"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "dlmalloc"
 version = "0.0.0"
@@ -978,6 +988,15 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "im-rc"
+version = "12.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rustc_version 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "installer"
 version = "0.0.0"
@@ -1316,6 +1335,7 @@ dependencies = [
  "cargo_metadata 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "colored 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiletest_rs 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "directories 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.5.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "vergen 3.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3030,6 +3050,11 @@ dependencies = [
  "toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "typenum"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "ucd-util"
 version = "0.1.1"
@@ -3285,6 +3310,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum derive_more 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3f57d78cf3bd45270dad4e70c21ec77a960b36c7a841ff9db76aaa775a8fb871"
 "checksum diff 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)" = "3c2b69f912779fbb121ceb775d74d51e915af17aaebc38d28a592843a2dd0a3a"
 "checksum difference 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "524cbf6897b527295dff137cec09ecf3a05f4fddffd7dfcd1585403449e74198"
+"checksum directories 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "72d337a64190607d4fcca2cb78982c5dd57f4916e19696b48a575fa746b6cb0f"
 "checksum either 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3be565ca5c557d7f59e7cfcf1844f9e3033650c929c6566f511e8005f205c1d0"
 "checksum elasticlunr-rs 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4837d77a1e157489a3933b743fd774ae75074e0e390b2b7f071530048a0d87ee"
 "checksum ena 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f56c93cc076508c549d9bb747f79aa9b4eb098be7b8cad8830c3137ef52d1e00"
@@ -3323,6 +3349,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum idna 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "38f09e0f0b1fb55fdee1f17470ad800da77af5186a1a76c026b679358b7e844e"
 "checksum if_chain 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4bac95d9aa0624e7b78187d6fb8ab012b41d9f6f54b1bcb61e61c4845f8357ec"
 "checksum ignore 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3e9faa7c84064f07b40da27044af629f578bc7994b650d3e458d0c29183c1d91"
+"checksum im-rc 12.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d4591152fd573cf453a890b5f9fdc5c328a751a0785539316739d5f85e5c468c"
 "checksum is-match 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7e5b386aef33a1c677be65237cb9d32c3f3ef56bd035949710c4bb13083eb053"
 "checksum itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)" = "f58856976b776fedd95533137617a02fb25719f40e7d9b01c7043cd65474f450"
 "checksum itoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "1306f3464951f30e30d12373d31c79fbd52d236e5e896fd92f96ec7babbbe60b"
@@ -3474,6 +3501,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum time 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "d825be0eb33fda1a7e68012d51e9c7f451dc1a69391e7fdc197060bb8c56667b"
 "checksum toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "a0263c6c02c4db6c8f7681f9fd35e90de799ebd4cfdeab77a38f4ff6b3d8c0d9"
 "checksum toml-query 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6854664bfc6df0360c695480836ee90e2d0c965f06db291d10be9344792d43e8"
+"checksum typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "612d636f949607bdf9b123b4a6f6d966dedf3ff669f7f045890d3a4a73948169"
 "checksum ucd-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "fd2be2d6639d0f8fe6cdda291ad456e23629558d466e2789d2c3e9892bda285d"
 "checksum unicode-bidi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
 "checksum unicode-normalization 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "6a0180bc61fc5a987082bfa111f4cc95c4caff7f9799f3e46df09163a937aa25"

config.toml.example

@@ -112,11 +112,11 @@
 # for each target triple.
 #target = ["x86_64-unknown-linux-gnu"] # defaults to just the build triple
 
-# Instead of downloading the src/stage0.txt version of Cargo specified, use
+# Instead of downloading the stage0.txt version of Cargo specified, use
 # this Cargo binary instead to build all Rust code
 #cargo = "/path/to/bin/cargo"
 
-# Instead of downloading the src/stage0.txt version of the compiler
+# Instead of downloading the stage0.txt version of the compiler
 # specified, use this rustc binary instead as the stage0 snapshot compiler.
 #rustc = "/path/to/bin/rustc"
 

src/bootstrap/bootstrap.py

@@ -154,7 +154,7 @@ def run(args, verbose=False, exception=False, **kwargs):
 
 def stage0_data(rust_root):
     """Build a dictionary from stage0.txt"""
-    nightlies = os.path.join(rust_root, "src/stage0.txt")
+    nightlies = os.path.join(rust_root, "stage0.txt")
     with open(nightlies, 'r') as nightlies:
         lines = [line.rstrip() for line in nightlies
                  if not line.startswith("#")]

src/bootstrap/bootstrap_test.py

@@ -28,8 +28,7 @@ class Stage0DataTestCase(unittest.TestCase):
     def setUp(self):
         self.rust_root = tempfile.mkdtemp()
         os.mkdir(os.path.join(self.rust_root, "src"))
-        with open(os.path.join(self.rust_root, "src",
-                               "stage0.txt"), "w") as stage0:
+        with open(os.path.join(self.rust_root, "stage0.txt"), "w") as stage0:
             stage0.write("#ignore\n\ndate: 2017-06-15\nrustc: beta\ncargo: beta")
 
     def tearDown(self):

src/bootstrap/doc.rs

@@ -70,6 +70,7 @@ macro_rules! book {
 book!(
     Nomicon, "src/doc/nomicon", "nomicon";
     Reference, "src/doc/reference", "reference";
+    EditionGuide, "src/doc/edition-guide", "edition-guide";
     RustdocBook, "src/doc/rustdoc", "rustdoc";
     RustcBook, "src/doc/rustc", "rustc";
     RustByExample, "src/doc/rust-by-example", "rust-by-example";

src/bootstrap/lib.rs

@@ -41,7 +41,7 @@
 //! When you execute `x.py build`, the steps which are executed are:
 //!
 //! * First, the python script is run. This will automatically download the
-//!   stage0 rustc and cargo according to `src/stage0.txt`, or use the cached
+//!   stage0 rustc and cargo according to `stage0.txt`, or use the cached
 //!   versions if they're available. These are then used to compile rustbuild
 //!   itself (using Cargo). Finally, control is then transferred to rustbuild.
 //!

src/bootstrap/sanity.rs

@@ -236,7 +236,7 @@ $ pacman -R cmake && pacman -S mingw-w64-x86_64-cmake
 
     if build.config.channel == "stable" {
         let mut stage0 = String::new();
-        t!(t!(File::open(build.src.join("src/stage0.txt")))
+        t!(t!(File::open(build.src.join("stage0.txt")))
             .read_to_string(&mut stage0));
         if stage0.contains("\ndev:") {
             panic!("bootstrapping from a dev compiler in a stable release, but \

src/liballoc/string.rs

@@ -618,6 +618,8 @@ impl String {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn from_utf16(v: &[u16]) -> Result<String, FromUtf16Error> {
+        // This isn't done via collect::<Result<_, _>>() for performance reasons.
+        // FIXME: the function can be simplified again when #48994 is closed.
         let mut ret = String::with_capacity(v.len());
         for c in decode_utf16(v.iter().cloned()) {
             if let Ok(c) = c {

src/libcore/array.rs

@@ -148,6 +148,15 @@ macro_rules! array_impls {
                 }
             }
 
+            #[unstable(feature = "try_from", issue = "33417")]
+            impl<'a, T> TryFrom<&'a [T]> for [T; $N] where T: Copy {
+                type Error = TryFromSliceError;
+
+                fn try_from(slice: &[T]) -> Result<[T; $N], TryFromSliceError> {
+                    <&Self>::try_from(slice).map(|r| *r)
+                }
+            }
+
             #[unstable(feature = "try_from", issue = "33417")]
             impl<'a, T> TryFrom<&'a [T]> for &'a [T; $N] {
                 type Error = TryFromSliceError;

src/libcore/num/mod.rs

@@ -1989,6 +1989,19 @@ big endian.
 ```
 let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -2008,6 +2021,19 @@ little endian.
 ```
 let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -2037,6 +2063,19 @@ let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"bi
         ", $le_bytes, "
     });
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3614,6 +3653,7 @@ assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));
 assert_eq!(", stringify!($SelfT), "::max_value().checked_next_power_of_two(), None);",
 $EndFeature, "
 ```"),
+            #[inline]
             #[stable(feature = "rust1", since = "1.0.0")]
             pub fn checked_next_power_of_two(self) -> Option<Self> {
                 self.one_less_than_next_power_of_two().checked_add(1)
@@ -3719,6 +3759,19 @@ big endian.
 ```
 let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3738,6 +3791,19 @@ little endian.
 ```
 let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3767,6 +3833,19 @@ let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"bi
         ", $le_bytes, "
     });
 assert_eq!(value, ", $swap_op, ");
+```
+
+When starting from a slice rather than an array, fallible conversion APIs can be used:
+
+```
+#![feature(try_from)]
+use std::convert::TryInto;
+
+fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {
+    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());
+    *input = rest;
+    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]