Auto merge of #62923 - Centril:rollup-53i3am3, r=Centril

Rollup of 11 pull requests

Successful merges:

 - #62261 (Take substs into account in `conservative_is_privately_uninhabited`)
 - #62528 (Add joining slices of slices with a slice separator, not just a single item)
 - #62738 (Remove uses of mem::uninitialized from std::sys::cloudabi)
 - #62784 (Add riscv32i-unknown-none-elf target)
 - #62808 (Revert "Disable stack probing for gnux32.")
 - #62814 (add support for hexagon-unknown-linux-musl)
 - #62822 (Improve some pointer-related documentation)
 - #62890 (Normalize use of backticks in compiler messages for libsyntax/*)
 - #62901 (cleanup: Remove `extern crate serialize as rustc_serialize`s)
 - #62905 (Normalize use of backticks in compiler messages for doc)
 - #62908 (normalize use of backticks for compiler messages in remaining modules)

Failed merges:

r? @ghost

src/ci/docker/dist-various-1/Dockerfile

@@ -112,6 +112,7 @@ ENV TARGETS=$TARGETS,thumbv7em-none-eabihf
 ENV TARGETS=$TARGETS,thumbv8m.base-none-eabi
 ENV TARGETS=$TARGETS,thumbv8m.main-none-eabi
 ENV TARGETS=$TARGETS,thumbv8m.main-none-eabihf
+ENV TARGETS=$TARGETS,riscv32i-unknown-none-elf
 ENV TARGETS=$TARGETS,riscv32imc-unknown-none-elf
 ENV TARGETS=$TARGETS,riscv32imac-unknown-none-elf
 ENV TARGETS=$TARGETS,riscv64imac-unknown-none-elf

src/doc/rustc/src/lints/index.md

@@ -19,7 +19,7 @@ warning: unused variable: `x`
 2 |     let x = 5;
   |         ^
   |
-  = note: #[warn(unused_variables)] on by default
+  = note: `#[warn(unused_variables)]` on by default
   = note: to avoid this warning, consider using `_x` instead
 ```
 

src/doc/rustc/src/lints/levels.md

@@ -53,7 +53,7 @@ warning: unused variable: `x`
 2 |     let x = 5;
   |         ^
   |
-  = note: #[warn(unused_variables)] on by default
+  = note: `#[warn(unused_variables)]` on by default
   = note: to avoid this warning, consider using `_x` instead
 ```
 
@@ -76,7 +76,7 @@ error: bitshift exceeds the type's number of bits
 2 |     100u8 << 10;
   |     ^^^^^^^^^^^
   |
-  = note: #[deny(exceeding_bitshifts)] on by default
+  = note: `#[deny(exceeding_bitshifts)]` on by default
 ```
 
 What's the difference between an error from a lint and a regular old error?
@@ -236,7 +236,7 @@ warning: bitshift exceeds the type's number of bits
 2 |     100u8 << 10;
   |     ^^^^^^^^^^^
   |
-  = note: #[warn(exceeding_bitshifts)] on by default
+  = note: `#[warn(exceeding_bitshifts)]` on by default
 
 warning: this expression will panic at run-time
  --> lib.rs:2:5

src/doc/rustc/src/lints/listing/allowed-by-default.md

@@ -165,7 +165,7 @@ pub struct Foo;
 When set to 'deny', this will produce:
 
 ```text
-error: type does not implement `fmt::Debug`; consider adding #[derive(Debug)] or a manual implementation
+error: type does not implement `fmt::Debug`; consider adding `#[derive(Debug)]` or a manual implementation
  --> src/main.rs:3:1
   |
 3 | pub struct Foo;

src/doc/rustc/src/lints/listing/deny-by-default.md

@@ -40,7 +40,7 @@ error: defaults for type parameters are only allowed in `struct`, `enum`, `type`
 4 | fn foo<T=i32>(t: T) {}
   |        ^
   |
-  = note: #[deny(invalid_type_param_default)] on by default
+  = note: `#[deny(invalid_type_param_default)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #36887 <https://github.com/rust-lang/rust/issues/36887>
 ```
@@ -74,7 +74,7 @@ error: private struct constructors are not usable through re-exports in outer mo
 5 |         ::S;
   |         ^^^
   |
-  = note: #[deny(legacy_constructor_visibility)] on by default
+  = note: `#[deny(legacy_constructor_visibility)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #39207 <https://github.com/rust-lang/rust/issues/39207>
 ```
@@ -84,9 +84,9 @@ error: private struct constructors are not usable through re-exports in outer mo
 
 The legacy_directory_ownership warning is issued when
 
-* There is a non-inline module with a #[path] attribute (e.g. #[path = "foo.rs"] mod bar;),
+* There is a non-inline module with a `#[path]` attribute (e.g. `#[path = "foo.rs"] mod bar;`),
 * The module's file ("foo.rs" in the above example) is not named "mod.rs", and
-* The module's file contains a non-inline child module without a #[path] attribute.
+* The module's file contains a non-inline child module without a `#[path]` attribute.
 
 The warning can be fixed by renaming the parent module to "mod.rs" and moving
 it into its own directory if appropriate.
@@ -139,7 +139,7 @@ const FOO: i32 = 5;
 This will produce:
 
 ```text
-error: const items should never be #[no_mangle]
+error: const items should never be `#[no_mangle]`
  --> src/main.rs:3:1
   |
 3 | const FOO: i32 = 5;
@@ -187,7 +187,7 @@ error: parenthesized parameters may only be used with a trait
 2 |   let x = 5 as usize();
   |                     ^^
   |
-  = note: #[deny(parenthesized_params_in_types_and_modules)] on by default
+  = note: `#[deny(parenthesized_params_in_types_and_modules)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 ```

src/doc/rustc/src/lints/listing/warn-by-default.md

@@ -90,7 +90,7 @@ warning: floating-point literals cannot be used in patterns
 4 |         5.0 => {},
   |         ^^^
   |
-  = note: #[warn(illegal_floating_point_literal_pattern)] on by default
+  = note: `#[warn(illegal_floating_point_literal_pattern)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #41620 <https://github.com/rust-lang/rust/issues/41620>
 ```
@@ -109,7 +109,7 @@ extern "C" {
 This will produce:
 
 ```text
-warning: found struct without foreign-function-safe representation annotation in foreign module, consider adding a #[repr(C)] attribute to the type
+warning: found struct without foreign-function-safe representation annotation in foreign module, consider adding a `#[repr(C)]` attribute to the type
  --> src/main.rs:2:20
   |
 2 |     static STATIC: String;
@@ -146,7 +146,7 @@ warning: cannot specify lifetime arguments explicitly if late bound lifetime par
 8 |     S.late::<'static>(&0, &0);
   |              ^^^^^^^
   |
-  = note: #[warn(late_bound_lifetime_arguments)] on by default
+  = note: `#[warn(late_bound_lifetime_arguments)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #42868 <https://github.com/rust-lang/rust/issues/42868>
 ```
@@ -327,7 +327,7 @@ warning: patterns aren't allowed in methods without bodies
 2 |     fn foo(mut arg: u8);
   |            ^^^^^^^
   |
-  = note: #[warn(patterns_in_fns_without_body)] on by default
+  = note: `#[warn(patterns_in_fns_without_body)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #35203 <https://github.com/rust-lang/rust/issues/35203>
 ```
@@ -406,7 +406,7 @@ fn foo() {}
 This will produce:
 
 ```text
-warning: function is marked #[no_mangle], but not exported
+warning: function is marked `#[no_mangle]`, but not exported
  --> src/main.rs:2:1
   |
 2 | fn foo() {}
@@ -433,7 +433,7 @@ static X: i32 = 4;
 This will produce:
 
 ```text
-warning: static is marked #[no_mangle], but not exported
+warning: static is marked `#[no_mangle]`, but not exported
  --> src/main.rs:2:1
   |
 2 | static X: i32 = 4;
@@ -496,7 +496,7 @@ warning: borrow of packed field requires unsafe function or block (error E0133)
 11 |     let y = &x.data.0;
    |             ^^^^^^^^^
    |
-   = note: #[warn(safe_packed_borrows)] on by default
+   = note: `#[warn(safe_packed_borrows)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #46043 <https://github.com/rust-lang/rust/issues/46043>
 ```
@@ -542,7 +542,7 @@ warning: bounds on generic parameters are not enforced in type aliases
 2 | type SendVec<T: Send> = Vec<T>;
   |                 ^^^^
   |
-  = note: #[warn(type_alias_bounds)] on by default
+  = note: `#[warn(type_alias_bounds)]` on by default
   = help: the bound will not be checked when the type alias is used, and should be removed
 ```
 
@@ -567,7 +567,7 @@ warning: type annotations needed
 4 |     if data.is_null() {}
   |             ^^^^^^^
   |
-  = note: #[warn(tyvar_behind_raw_pointer)] on by default
+  = note: `#[warn(tyvar_behind_raw_pointer)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in the 2018 edition!
   = note: for more information, see issue #46906 <https://github.com/rust-lang/rust/issues/46906>
 ```
@@ -787,7 +787,7 @@ warning: doc comment not used by rustdoc
 
 ## unused-features
 
-This lint detects unused or unknown features found in crate-level #[feature] directives.
+This lint detects unused or unknown features found in crate-level `#[feature]` directives.
 To fix this, simply remove the feature flag.
 
 ## unused-imports
@@ -839,7 +839,7 @@ warning: unused macro definition
 
 ## unused-must-use
 
-This lint detects unused result of a type flagged as #[must_use]. Some
+This lint detects unused result of a type flagged as `#[must_use]`. Some
 example code that triggers this lint:
 
 ```rust

src/liballoc/slice.rs

@@ -494,10 +494,10 @@ impl<T> [T] {
     /// assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn concat<Separator: ?Sized>(&self) -> T::Output
-        where T: SliceConcat<Separator>
+    pub fn concat<Item: ?Sized>(&self) -> <Self as Concat<Item>>::Output
+        where Self: Concat<Item>
     {
-        SliceConcat::concat(self)
+        Concat::concat(self)
     }
 
     /// Flattens a slice of `T` into a single value `Self::Output`, placing a
@@ -508,12 +508,13 @@ impl<T> [T] {
     /// ```
     /// assert_eq!(["hello", "world"].join(" "), "hello world");
     /// assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
+    /// assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);
     /// ```
     #[stable(feature = "rename_connect_to_join", since = "1.3.0")]
-    pub fn join<Separator: ?Sized>(&self, sep: &Separator) -> T::Output
-        where T: SliceConcat<Separator>
+    pub fn join<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
+        where Self: Join<Separator>
     {
-        SliceConcat::join(self, sep)
+        Join::join(self, sep)
     }
 
     /// Flattens a slice of `T` into a single value `Self::Output`, placing a
@@ -528,10 +529,10 @@ impl<T> [T] {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_deprecated(since = "1.3.0", reason = "renamed to join")]
-    pub fn connect<Separator: ?Sized>(&self, sep: &Separator) -> T::Output
-        where T: SliceConcat<Separator>
+    pub fn connect<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
+        where Self: Join<Separator>
     {
-        SliceConcat::join(self, sep)
+        Join::join(self, sep)
     }
 
 }
@@ -578,45 +579,83 @@ impl [u8] {
 // Extension traits for slices over specific kinds of data
 ////////////////////////////////////////////////////////////////////////////////
 
-/// Helper trait for [`[T]::concat`](../../std/primitive.slice.html#method.concat)
-/// and [`[T]::join`](../../std/primitive.slice.html#method.join)
+/// Helper trait for [`[T]::concat`](../../std/primitive.slice.html#method.concat).
+///
+/// Note: the `Item` type parameter is not used in this trait,
+/// but it allows impls to be more generic.
+/// Without it, we get this error:
+///
+/// ```error
+/// error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predica
+///    --> src/liballoc/slice.rs:608:6
+///     |
+/// 608 | impl<T: Clone, V: Borrow<[T]>> Concat for [V] {
+///     |      ^ unconstrained type parameter
+/// ```
+///
+/// This is because there could exist `V` types with multiple `Borrow<[_]>` impls,
+/// such that multiple `T` types would apply:
+///
+/// ```
+/// # #[allow(dead_code)]
+/// pub struct Foo(Vec<u32>, Vec<String>);
+///
+/// impl std::borrow::Borrow<[u32]> for Foo {
+///     fn borrow(&self) -> &[u32] { &self.0 }
+/// }
+///
+/// impl std::borrow::Borrow<[String]> for Foo {
+///     fn borrow(&self) -> &[String] { &self.1 }
+/// }
+/// ```
 #[unstable(feature = "slice_concat_trait", issue = "27747")]
-pub trait SliceConcat<Separator: ?Sized>: Sized {
+pub trait Concat<Item: ?Sized> {
     #[unstable(feature = "slice_concat_trait", issue = "27747")]
     /// The resulting type after concatenation
     type Output;
 
     /// Implementation of [`[T]::concat`](../../std/primitive.slice.html#method.concat)
     #[unstable(feature = "slice_concat_trait", issue = "27747")]
-    fn concat(slice: &[Self]) -> Self::Output;
+    fn concat(slice: &Self) -> Self::Output;
+}
+
+/// Helper trait for [`[T]::join`](../../std/primitive.slice.html#method.join)
+#[unstable(feature = "slice_concat_trait", issue = "27747")]
+pub trait Join<Separator> {
+    #[unstable(feature = "slice_concat_trait", issue = "27747")]
+    /// The resulting type after concatenation
+    type Output;
 
     /// Implementation of [`[T]::join`](../../std/primitive.slice.html#method.join)
     #[unstable(feature = "slice_concat_trait", issue = "27747")]
-    fn join(slice: &[Self], sep: &Separator) -> Self::Output;
+    fn join(slice: &Self, sep: Separator) -> Self::Output;
 }
 
-#[unstable(feature = "slice_concat_ext",
-           reason = "trait should not have to exist",
-           issue = "27747")]
-impl<T: Clone, V: Borrow<[T]>> SliceConcat<T> for V {
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Concat<T> for [V] {
     type Output = Vec<T>;
 
-    fn concat(slice: &[Self]) -> Vec<T> {
+    fn concat(slice: &Self) -> Vec<T> {
         let size = slice.iter().map(|slice| slice.borrow().len()).sum();
         let mut result = Vec::with_capacity(size);
         for v in slice {
             result.extend_from_slice(v.borrow())
         }
         result
     }
+}
+
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Join<&T> for [V] {
+    type Output = Vec<T>;
 
-    fn join(slice: &[Self], sep: &T) -> Vec<T> {
+    fn join(slice: &Self, sep: &T) -> Vec<T> {
         let mut iter = slice.iter();
         let first = match iter.next() {
             Some(first) => first,
             None => return vec![],
         };
-        let size = slice.iter().map(|slice| slice.borrow().len()).sum::<usize>() + slice.len() - 1;
+        let size = slice.iter().map(|v| v.borrow().len()).sum::<usize>() + slice.len() - 1;
         let mut result = Vec::with_capacity(size);
         result.extend_from_slice(first.borrow());
 
@@ -628,6 +667,29 @@ impl<T: Clone, V: Borrow<[T]>> SliceConcat<T> for V {
     }
 }
 
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Join<&[T]> for [V] {
+    type Output = Vec<T>;
+
+    fn join(slice: &Self, sep: &[T]) -> Vec<T> {
+        let mut iter = slice.iter();
+        let first = match iter.next() {
+            Some(first) => first,
+            None => return vec![],
+        };
+        let size = slice.iter().map(|v| v.borrow().len()).sum::<usize>() +
+            sep.len() * (slice.len() - 1);
+        let mut result = Vec::with_capacity(size);
+        result.extend_from_slice(first.borrow());
+
+        for v in iter {
+            result.extend_from_slice(sep);
+            result.extend_from_slice(v.borrow())
+        }
+        result
+    }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Standard trait implementations for slices
 ////////////////////////////////////////////////////////////////////////////////