Rollup of 29 pull requests

.gitmodules

@@ -62,3 +62,6 @@
 	url = https://github.com/rust-lang-nursery/clang.git
 	branch = rust-release-80-v1
 
+[submodule "src/doc/rustc-guide"]
+	path = src/doc/rustc-guide
+	url = https://github.com/rust-lang/rustc-guide.git

CONTRIBUTING.md

@@ -640,13 +640,13 @@ are:
 * **Google!** ([search only in Rust Documentation][gsearchdocs] to find types, traits, etc. quickly)
 * Don't be afraid to ask! The Rust community is friendly and helpful.
 
-[rustc guide]: https://rust-lang-nursery.github.io/rustc-guide/about-this-guide.html
+[rustc guide]: https://rust-lang.github.io/rustc-guide/about-this-guide.html
 [gdfrustc]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc/
 [gsearchdocs]: https://www.google.com/search?q=site:doc.rust-lang.org+your+query+here
 [rif]: http://internals.rust-lang.org
 [rr]: https://doc.rust-lang.org/book/README.html
 [rustforge]: https://forge.rust-lang.org/
 [tlgba]: http://tomlee.co/2014/04/a-more-detailed-tour-of-the-rust-compiler/
 [ro]: http://www.rustaceans.org/
-[rctd]: https://rust-lang-nursery.github.io/rustc-guide/tests/intro.html
+[rctd]: https://rust-lang.github.io/rustc-guide/tests/intro.html
 [cheatsheet]: https://buildbot2.rust-lang.org/homu/

README.md

@@ -233,7 +233,7 @@ Also, you may find the [rustdocs for the compiler itself][rustdocs] useful.
 [IRC]: https://en.wikipedia.org/wiki/Internet_Relay_Chat
 [#rust]: irc://irc.mozilla.org/rust
 [#rust-beginners]: irc://irc.mozilla.org/rust-beginners
-[rustc guide]: https://rust-lang-nursery.github.io/rustc-guide/about-this-guide.html
+[rustc guide]: https://rust-lang.github.io/rustc-guide/about-this-guide.html
 [rustdocs]: https://doc.rust-lang.org/nightly/nightly-rustc/rustc/
 
 ## License

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/README.md

@@ -12,4 +12,4 @@ There is also useful content in the following READMEs, which are gradually being
 - https://github.com/rust-lang/rust/tree/master/src/librustc/infer/higher_ranked
 - https://github.com/rust-lang/rust/tree/master/src/librustc/infer/lexical_region_resolve
 
-[rustc guide]: https://rust-lang-nursery.github.io/rustc-guide/about-this-guide.html
+[rustc guide]: https://rust-lang.github.io/rustc-guide/about-this-guide.html

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/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.
 //!
@@ -777,10 +777,10 @@ impl Build {
     fn cflags(&self, target: Interned<String>, which: GitRepo) -> Vec<String> {
         // Filter out -O and /O (the optimization flags) that we picked up from
         // cc-rs because the build scripts will determine that for themselves.
-        let mut base: Vec<String> = self.cc[&target].args().iter()
+        let mut base = self.cc[&target].args().iter()
                            .map(|s| s.to_string_lossy().into_owned())
                            .filter(|s| !s.starts_with("-O") && !s.starts_with("/O"))
-                           .collect::<Vec<_>>();
+                           .collect::<Vec<String>>();
 
         // If we're compiling on macOS then we add a few unconditional flags
         // indicating that we want libc++ (more filled out than libstdc++) and

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/doc/index.md

@@ -21,6 +21,9 @@ nav {
 #search-but:hover, #search-input:focus {
     border-color: #55a9ff;
 }
+h2 {
+    font-size: 18px;
+}
 </style>
 
 Welcome to an overview of the documentation provided by the Rust project.

src/doc/rustc/src/contributing.md

@@ -1,6 +1,6 @@
 # Contributing to rustc
 
 We'd love to have your help improving `rustc`! To that end, we've written [a
-whole book](https://rust-lang-nursery.github.io/rustc-guide/) on its
+whole book](https://rust-lang.github.io/rustc-guide/) on its
 internals, how it works, and how to get started working on it. To learn
-more, you'll want to check that out.
+more, you'll want to check that out.

src/doc/unstable-book/src/language-features/plugin.md

@@ -181,7 +181,6 @@ that warns about any item named `lintme`.
 ```rust,ignore
 #![feature(plugin_registrar)]
 #![feature(box_syntax, rustc_private)]
-#![feature(macro_at_most_once_rep)]
 
 extern crate syntax;
 

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/iter/iterator.rs

@@ -519,7 +519,7 @@ pub trait Iterator {
     /// element.
     ///
     /// `map()` transforms one iterator into another, by means of its argument:
-    /// something that implements `FnMut`. It produces a new iterator which
+    /// something that implements [`FnMut`]. It produces a new iterator which
     /// calls this closure on each element of the original iterator.
     ///
     /// If you are good at thinking in types, you can think of `map()` like this:
@@ -533,6 +533,7 @@ pub trait Iterator {
     /// more idiomatic to use [`for`] than `map()`.
     ///
     /// [`for`]: ../../book/ch03-05-control-flow.html#looping-through-a-collection-with-for
+    /// [`FnMut`]: ../../std/ops/trait.FnMut.html
     ///
     /// # Examples
     ///

src/libcore/lib.rs

@@ -93,7 +93,6 @@
 #![feature(never_type)]
 #![feature(nll)]
 #![feature(exhaustive_patterns)]
-#![feature(macro_at_most_once_rep)]
 #![feature(no_core)]
 #![feature(on_unimplemented)]
 #![feature(optin_builtin_traits)]

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!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3719,6 +3758,19 @@ big endian.
 ```
 let value = ", stringify!($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!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3738,6 +3790,19 @@ little endian.
 ```
 let value = ", stringify!($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!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())
+}
 ```"),
             #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
             #[rustc_const_unstable(feature = "const_int_conversion")]
@@ -3767,6 +3832,19 @@ let value = ", stringify!($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")]

src/libcore/ptr.rs

@@ -189,12 +189,22 @@ pub use intrinsics::write_bytes;
 /// i.e., you do not usually have to worry about such issues unless you call `drop_in_place`
 /// manually.
 #[stable(feature = "drop_in_place", since = "1.8.0")]
+#[inline(always)]
+pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
+    real_drop_in_place(&mut *to_drop)
+}
+
+// The real `drop_in_place` -- the one that gets called implicitly when variables go
+// out of scope -- should have a safe reference and not a raw pointer as argument
+// type.  When we drop a local variable, we access it with a pointer that behaves
+// like a safe reference; transmuting that to a raw pointer does not mean we can
+// actually access it with raw pointers.
 #[lang = "drop_in_place"]
 #[allow(unconditional_recursion)]
-pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) {
+unsafe fn real_drop_in_place<T: ?Sized>(to_drop: &mut T) {
     // Code here does not matter - this is replaced by the
     // real drop glue by the compiler.
-    drop_in_place(to_drop);
+    real_drop_in_place(to_drop)
 }
 
 /// Creates a null raw pointer.

src/libcore/str/lossy.rs

@@ -62,18 +62,15 @@ impl<'a> Iterator for Utf8LossyChunksIter<'a> {
         }
 
         const TAG_CONT_U8: u8 = 128;
-        fn unsafe_get(xs: &[u8], i: usize) -> u8 {
-            unsafe { *xs.get_unchecked(i) }
-        }
         fn safe_get(xs: &[u8], i: usize) -> u8 {
-            if i >= xs.len() { 0 } else { unsafe_get(xs, i) }
+            *xs.get(i).unwrap_or(&0)
         }
 
         let mut i = 0;
         while i < self.source.len() {
             let i_ = i;
 
-            let byte = unsafe_get(self.source, i);
+            let byte = unsafe { *self.source.get_unchecked(i) };
             i += 1;
 
             if byte < 128 {