Merge remote-tracking branch 'upstream/master'

11 files changed, 98 insertions, 58 deletions

diff --git a/src/doc/index.md b/src/doc/index.md
index b79a349a453..55897e5a3e9 100644
--- a/src/doc/index.md
+++ b/src/doc/index.md
@@ -107,3 +107,9 @@ Rust. It's also sometimes called "the 'nomicon."
 ## The Unstable Book
 
 [The Unstable Book](unstable-book/index.html) has documentation for unstable features.
+
+## The `rustc` Contribution Guide
+
+[The `rustc` Guide](https://rust-lang.github.io/rustc-guide/) documents how
+the compiler works and how to contribute to it. This is useful if you want to build
+or modify the Rust compiler from source (e.g. to target something non-standard).
diff --git a/src/doc/rust.css b/src/doc/rust.css
index 5f216169efe..631f64a11db 100644
--- a/src/doc/rust.css
+++ b/src/doc/rust.css
@@ -1,15 +1,3 @@
-/**
- * Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
- * file at the top-level directory of this distribution and at
- * http://rust-lang.org/COPYRIGHT.
- * With elements taken from Bootstrap v3.0.2 (MIT licensed).
- *
- * Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
- * http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
- * <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
- * option. This file may not be copied, modified, or distributed
- * except according to those terms.
- */
 @font-face {
 	font-family: 'Fira Sans';
 	font-style: normal;
diff --git a/src/doc/rustc/src/lints/listing/warn-by-default.md b/src/doc/rustc/src/lints/listing/warn-by-default.md
index b01aed0915d..7fbbe686b5b 100644
--- a/src/doc/rustc/src/lints/listing/warn-by-default.md
+++ b/src/doc/rustc/src/lints/listing/warn-by-default.md
@@ -24,7 +24,7 @@ warning: attempt to add with overflow
 
 ## dead-code
 
-This lint detects detect unused, unexported items. Some
+This lint detects unused, unexported items. Some
 example code that triggers this lint:
 
 ```rust
@@ -44,7 +44,7 @@ warning: function is never used: `foo`
 
 ## deprecated
 
-This lint detects detects use of deprecated items. Some
+This lint detects use of deprecated items. Some
 example code that triggers this lint:
 
 ```rust
@@ -119,7 +119,7 @@ warning: found struct without foreign-function-safe representation annotation in
 
 ## late-bound-lifetime-arguments
 
-This lint detects detects generic lifetime arguments in path segments with
+This lint detects generic lifetime arguments in path segments with
 late bound lifetime parameters. Some example code that triggers this lint:
 
 ```rust
@@ -381,7 +381,7 @@ extern crate macro_crate_test;
 
 ## private-in-public
 
-This lint detects detect private items in public interfaces not caught by the old implementation. Some
+This lint detects private items in public interfaces not caught by the old implementation. Some
 example code that triggers this lint:
 
 ```rust,ignore
@@ -659,7 +659,7 @@ warning: unknown lint: `not_a_real_lint`
 
 ## unreachable-code
 
-This lint detects detects unreachable code paths. Some example code that
+This lint detects unreachable code paths. Some example code that
 triggers this lint:
 
 ```rust,no_run
@@ -681,7 +681,7 @@ warning: unreachable statement
 
 ## unreachable-patterns
 
-This lint detects detects unreachable patterns. Some
+This lint detects unreachable patterns. Some
 example code that triggers this lint:
 
 ```rust
@@ -716,11 +716,11 @@ annotations now.
 
 ## unused-allocation
 
-This lint detects detects unnecessary allocations that can be eliminated.
+This lint detects unnecessary allocations that can be eliminated.
 
 ## unused-assignments
 
-This lint detects detect assignments that will never be read. Some
+This lint detects assignments that will never be read. Some
 example code that triggers this lint:
 
 ```rust
@@ -741,7 +741,7 @@ warning: value assigned to `x` is never read
 
 ## unused-attributes
 
-This lint detects detects attributes that were not used by the compiler. Some
+This lint detects attributes that were not used by the compiler. Some
 example code that triggers this lint:
 
 ```rust
@@ -785,7 +785,7 @@ warning: comparison is useless due to type limits
 
 ## unused-doc-comment
 
-This lint detects detects doc comments that aren't used by rustdoc. Some
+This lint detects doc comments that aren't used by rustdoc. Some
 example code that triggers this lint:
 
 ```rust
@@ -831,7 +831,7 @@ warning: unused import: `std::collections::HashMap`
 
 ## unused-macros
 
-This lint detects detects macros that were not used. Some example code that
+This lint detects macros that were not used. Some example code that
 triggers this lint:
 
 ```rust
@@ -884,7 +884,7 @@ warning: unused `std::result::Result` that must be used
 
 ## unused-mut
 
-This lint detects detect mut variables which don't need to be mutable. Some
+This lint detects mut variables which don't need to be mutable. Some
 example code that triggers this lint:
 
 ```rust
@@ -946,7 +946,7 @@ warning: unnecessary `unsafe` block
 
 ## unused-variables
 
-This lint detects detect variables which are not used in any way. Some
+This lint detects variables which are not used in any way. Some
 example code that triggers this lint:
 
 ```rust
diff --git a/src/doc/rustc/src/what-is-rustc.md b/src/doc/rustc/src/what-is-rustc.md
index bed1b71c24e..9dcc9f7daa9 100644
--- a/src/doc/rustc/src/what-is-rustc.md
+++ b/src/doc/rustc/src/what-is-rustc.md
@@ -50,7 +50,7 @@ fn main() {
 And a `foo.rs` that had this:
 
 ```rust,ignore
-fn hello() {
+pub fn hello() {
     println!("Hello, world!");
 }
 ```
@@ -65,4 +65,4 @@ No need to tell `rustc` about `foo.rs`; the `mod` statements give it
 everything that it needs. This is different than how you would use a C
 compiler, where you invoke the compiler on each file, and then link
 everything together. In other words, the *crate* is a translation unit, not a
-particular module.
\ No newline at end of file
+particular module.
diff --git a/src/doc/rustdoc/src/documentation-tests.md b/src/doc/rustdoc/src/documentation-tests.md
index dd8dcb7ff9b..dcc13f53493 100644
--- a/src/doc/rustdoc/src/documentation-tests.md
+++ b/src/doc/rustdoc/src/documentation-tests.md
@@ -171,7 +171,7 @@ compiles, while only showing the parts that are relevant to that part of your
 explanation.
 
 The `#`-hiding of lines can be prevented by using two consecutive hashes
-`##`. This only needs to be done with with the first `#` which would've
+`##`. This only needs to be done with the first `#` which would've
 otherwise caused hiding. If we have a string literal like the following,
 which has a line that starts with a `#`:
 
diff --git a/src/doc/rustdoc/src/unstable-features.md b/src/doc/rustdoc/src/unstable-features.md
index 43cdab27e9d..905b0646534 100644
--- a/src/doc/rustdoc/src/unstable-features.md
+++ b/src/doc/rustdoc/src/unstable-features.md
@@ -402,3 +402,18 @@ Using `index-page` option enables `enable-index-page` option as well.
 ### `--enable-index-page`: generate a default index page for docs
 
 This feature allows the generation of a default index-page which lists the generated crates.
+
+### `--static-root-path`: control how static files are loaded in HTML output
+
+Using this flag looks like this:
+
+```bash
+$ rustdoc src/lib.rs -Z unstable-options --static-root-path '/cache/'
+```
+
+This flag controls how rustdoc links to its static files on HTML pages. If you're hosting a lot of
+crates' docs generated by the same version of rustdoc, you can use this flag to cache rustdoc's CSS,
+JavaScript, and font files in a single location, rather than duplicating it once per "doc root"
+(grouping of crate docs generated into the same output directory, like with `cargo doc`). Per-crate
+files like the search index will still load from the documentation root, but anything that gets
+renamed with `--resource-suffix` will load from the given path.
diff --git a/src/doc/unstable-book/src/language-features/cfg-attr-multi.md b/src/doc/unstable-book/src/language-features/cfg-attr-multi.md
deleted file mode 100644
index 6365d3e71c6..00000000000
--- a/src/doc/unstable-book/src/language-features/cfg-attr-multi.md
+++ /dev/null
@@ -1,20 +0,0 @@
-# `cfg_attr_multi`
-
-The tracking issue for this feature is: [#54881]
-The RFC for this feature is: [#2539]
-
-[#54881]: https://github.com/rust-lang/rust/issues/54881
-[#2539]: https://github.com/rust-lang/rfcs/pull/2539
-
-------------------------
-
-This feature flag lets you put multiple attributes into a `cfg_attr` attribute.
-
-Example:
-
-```rust,ignore
-#[cfg_attr(all(), must_use, optimize)]
-```
-
-Because `cfg_attr` resolves before procedural macros, this does not affect
-macro resolution at all.
\ No newline at end of file
diff --git a/src/doc/unstable-book/src/language-features/non-ascii-idents.md b/src/doc/unstable-book/src/language-features/non-ascii-idents.md
index efb5495fe26..46957c00bf9 100644
--- a/src/doc/unstable-book/src/language-features/non-ascii-idents.md
+++ b/src/doc/unstable-book/src/language-features/non-ascii-idents.md
@@ -1,8 +1,8 @@
 # `non_ascii_idents`
 
-The tracking issue for this feature is: [#28979]
+The tracking issue for this feature is: [#55467]
 
-[#28979]: https://github.com/rust-lang/rust/issues/28979
+[#55467]: https://github.com/rust-lang/rust/issues/55467
 
 ------------------------
 
diff --git a/src/doc/unstable-book/src/language-features/re-rebalance-coherence.md b/src/doc/unstable-book/src/language-features/re-rebalance-coherence.md
new file mode 100644
index 00000000000..1e74652a890
--- /dev/null
+++ b/src/doc/unstable-book/src/language-features/re-rebalance-coherence.md
@@ -0,0 +1,23 @@
+# `re_rebalance_coherence`
+
+The tracking issue for this feature is: [#55437]
+
+[#55437]: https://github.com/rust-lang/rust/issues/55437
+
+------------------------
+
+The `re_rebalance_coherence` feature tweaks the rules regarding which trait
+impls are allowed in crates.
+The following rule is used:
+
+Given `impl<P1..=Pn> Trait<T1..=Tn> for T0`, an impl is valid only if at
+least one of the following is true:
+- `Trait` is a local trait
+- All of
+  - At least one of the types `T0..=Tn` must be a local type. Let `Ti` be the
+    first such type.
+  - No uncovered type parameters `P1..=Pn` may appear in `T0..Ti` (excluding
+    `Ti`)
+
+
+See the [RFC](https://github.com/rust-lang/rfcs/blob/master/text/2451-re-rebalancing-coherence.md) for details.
diff --git a/src/doc/unstable-book/src/language-features/repr-packed.md b/src/doc/unstable-book/src/language-features/repr-packed.md
deleted file mode 100644
index 2dd763d04b0..00000000000
--- a/src/doc/unstable-book/src/language-features/repr-packed.md
+++ /dev/null
@@ -1,8 +0,0 @@
-# `repr_packed`
-
-The tracking issue for this feature is [#33158]
-
-[#33158]: https://github.com/rust-lang/rust/issues/33158
-
-------------------------
-
diff --git a/src/doc/unstable-book/src/language-features/type-alias-enum-variants.md b/src/doc/unstable-book/src/language-features/type-alias-enum-variants.md
new file mode 100644
index 00000000000..bcdeafc4b11
--- /dev/null
+++ b/src/doc/unstable-book/src/language-features/type-alias-enum-variants.md
@@ -0,0 +1,36 @@
+# `type_alias_enum_variants`
+
+The tracking issue for this feature is: [#49683]
+
+[#49683]: https://github.com/rust-lang/rust/issues/49683
+
+------------------------
+
+The `type_alias_enum_variants` feature enables the use of variants on type
+aliases that refer to enums, as both a constructor and a pattern. That is,
+it allows for the syntax `EnumAlias::Variant`, which behaves exactly the same
+as `Enum::Variant` (assuming that `EnumAlias` is an alias for some enum type
+`Enum`).
+
+Note that since `Self` exists as a type alias, this feature also enables the
+use of the syntax `Self::Variant` within an impl block for an enum type.
+
+```rust
+#![feature(type_alias_enum_variants)]
+
+enum Foo {
+    Bar(i32),
+    Baz { i: i32 },
+}
+
+type Alias = Foo;
+
+fn main() {
+    let t = Alias::Bar(0);
+    let t = Alias::Baz { i: 0 };
+    match t {
+        Alias::Bar(_i) => {}
+        Alias::Baz { i: _i } => {}
+    }
+}
+```