Auto merge of #35908 - jonathandturner:rollup, r=jonathandturner

Rollup of 20 pull requests

- Successful merges: #35360, #35526, #35809, #35817, #35820, #35824, #35835, #35841, #35842, #35858, #35860, #35861, #35864, #35878, #35879, #35881, #35882, #35889, #35891, #35901
- Failed merges: #35395

CONTRIBUTING.md

@@ -230,7 +230,7 @@ To find documentation-related issues, sort by the [A-docs label][adocs].
 In many cases, you don't need a full `make doc`. You can use `rustdoc` directly
 to check small fixes. For example, `rustdoc src/doc/reference.md` will render
 reference to `doc/reference.html`. The CSS might be messed up, but you can
-verify that HTML is right.
+verify that the HTML is right.
 
 ## Issue Triage
 

src/doc/book/traits.md

@@ -47,6 +47,34 @@ As you can see, the `trait` block looks very similar to the `impl` block,
 but we don’t define a body, only a type signature. When we `impl` a trait,
 we use `impl Trait for Item`, rather than only `impl Item`.
 
+`Self` may be used in a type annotation to refer to an instance of the type
+implementing this trait passed as a parameter. `Self`, `&Self` or `&mut Self`
+may be used depending on the level of ownership required.
+
+```rust
+struct Circle {
+    x: f64,
+    y: f64,
+    radius: f64,
+}
+
+trait HasArea {
+    fn area(&self) -> f64;
+
+    fn is_larger(&self, &Self) -> bool;
+}
+
+impl HasArea for Circle {
+    fn area(&self) -> f64 {
+        std::f64::consts::PI * (self.radius * self.radius)
+    }
+
+    fn is_larger(&self, other: &Self) -> bool {
+        self.area() > other.area()
+    }
+}
+```
+
 ## Trait bounds on generic functions
 
 Traits are useful because they allow a type to make certain promises about its

src/etc/CONFIGS.md

@@ -6,6 +6,7 @@ These are some links to repos with configs which ease the use of rust.
 
 * [rust.vim](https://github.com/rust-lang/rust.vim)
 * [emacs rust-mode](https://github.com/rust-lang/rust-mode)
+* [sublime-rust](https://github.com/rust-lang/sublime-rust)
 * [gedit-config](https://github.com/rust-lang/gedit-config)
 * [kate-config](https://github.com/rust-lang/kate-config)
 * [nano-config](https://github.com/rust-lang/nano-config)

src/liballoc/rc.rs

@@ -263,6 +263,23 @@ impl<T> Rc<T> {
     }
 
     /// Checks if `Rc::try_unwrap` would return `Ok`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(rc_would_unwrap)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let x = Rc::new(3);
+    /// assert!(Rc::would_unwrap(&x));
+    /// assert_eq!(Rc::try_unwrap(x), Ok(3));
+    ///
+    /// let x = Rc::new(4);
+    /// let _y = x.clone();
+    /// assert!(!Rc::would_unwrap(&x));
+    /// assert_eq!(Rc::try_unwrap(x), Err(Rc::new(4)));
+    /// ```
     #[unstable(feature = "rc_would_unwrap",
                reason = "just added for niche usecase",
                issue = "28356")]

src/libcollections/string.rs

@@ -132,7 +132,7 @@ use boxed::Box;
 /// [`OsString`]: ../../std/ffi/struct.OsString.html
 ///
 /// Indexing is intended to be a constant-time operation, but UTF-8 encoding
-/// does not allow us to do this. Furtheremore, it's not clear what sort of
+/// does not allow us to do this. Furthermore, it's not clear what sort of
 /// thing the index should return: a byte, a codepoint, or a grapheme cluster.
 /// The [`as_bytes()`] and [`chars()`] methods return iterators over the first
 /// two, respectively.

src/libcore/ops.rs

@@ -299,26 +299,63 @@ sub_impl! { usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 }
 ///
 /// # Examples
 ///
-/// A trivial implementation of `Mul`. When `Foo * Foo` happens, it ends up
-/// calling `mul`, and therefore, `main` prints `Multiplying!`.
+/// Implementing a `Mul`tipliable rational number struct:
 ///
 /// ```
 /// use std::ops::Mul;
 ///
-/// struct Foo;
+/// // The uniqueness of rational numbers in lowest terms is a consequence of
+/// // the fundamental theorem of arithmetic.
+/// #[derive(Eq)]
+/// #[derive(PartialEq, Debug)]
+/// struct Rational {
+///     nominator: usize,
+///     denominator: usize,
+/// }
 ///
-/// impl Mul for Foo {
-///     type Output = Foo;
+/// impl Rational {
+///     fn new(nominator: usize, denominator: usize) -> Self {
+///         if denominator == 0 {
+///             panic!("Zero is an invalid denominator!");
+///         }
 ///
-///     fn mul(self, _rhs: Foo) -> Foo {
-///         println!("Multiplying!");
-///         self
+///         // Reduce to lowest terms by dividing by the greatest common
+///         // divisor.
+///         let gcd = gcd(nominator, denominator);
+///         Rational {
+///             nominator: nominator / gcd,
+///             denominator: denominator / gcd,
+///         }
 ///     }
 /// }
 ///
-/// fn main() {
-///     Foo * Foo;
+/// impl Mul for Rational {
+///     // The multiplication of rational numbers is a closed operation.
+///     type Output = Self;
+///
+///     fn mul(self, rhs: Self) -> Self {
+///         let nominator = self.nominator * rhs.nominator;
+///         let denominator = self.denominator * rhs.denominator;
+///         Rational::new(nominator, denominator)
+///     }
+/// }
+///
+/// // Euclid's two-thousand-year-old algorithm for finding the greatest common
+/// // divisor.
+/// fn gcd(x: usize, y: usize) -> usize {
+///     let mut x = x;
+///     let mut y = y;
+///     while y != 0 {
+///         let t = y;
+///         y = x % y;
+///         x = t;
+///     }
+///     x
 /// }
+///
+/// assert_eq!(Rational::new(1, 2), Rational::new(2, 4));
+/// assert_eq!(Rational::new(2, 3) * Rational::new(3, 4),
+///            Rational::new(1, 2));
 /// ```
 ///
 /// Note that `RHS = Self` by default, but this is not mandatory. Here is an
@@ -486,26 +523,34 @@ div_impl_float! { f32 f64 }
 ///
 /// # Examples
 ///
-/// A trivial implementation of `Rem`. When `Foo % Foo` happens, it ends up
-/// calling `rem`, and therefore, `main` prints `Remainder-ing!`.
+/// This example implements `Rem` on a `SplitSlice` object. After `Rem` is
+/// implemented, one can use the `%` operator to find out what the remaining
+/// elements of the slice would be after splitting it into equal slices of a
+/// given length.
 ///
 /// ```
 /// use std::ops::Rem;
 ///
-/// struct Foo;
+/// #[derive(PartialEq, Debug)]
+/// struct SplitSlice<'a, T: 'a> {
+///     slice: &'a [T],
+/// }
 ///
-/// impl Rem for Foo {
-///     type Output = Foo;
+/// impl<'a, T> Rem<usize> for SplitSlice<'a, T> {
+///     type Output = SplitSlice<'a, T>;
 ///
-///     fn rem(self, _rhs: Foo) -> Foo {
-///         println!("Remainder-ing!");
-///         self
+///     fn rem(self, modulus: usize) -> Self {
+///         let len = self.slice.len();
+///         let rem = len % modulus;
+///         let start = len - rem;
+///         SplitSlice {slice: &self.slice[start..]}
 ///     }
 /// }
 ///
-/// fn main() {
-///     Foo % Foo;
-/// }
+/// // If we were to divide &[0, 1, 2, 3, 4, 5, 6, 7] into slices of size 3,
+/// // the remainder would be &[6, 7]
+/// assert_eq!(SplitSlice { slice: &[0, 1, 2, 3, 4, 5, 6, 7] } % 3,
+///            SplitSlice { slice: &[6, 7] });
 /// ```
 #[lang = "rem"]
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -694,26 +739,41 @@ not_impl! { bool usize u8 u16 u32 u64 isize i8 i16 i32 i64 }
 ///
 /// # Examples
 ///
-/// A trivial implementation of `BitAnd`. When `Foo & Foo` happens, it ends up
-/// calling `bitand`, and therefore, `main` prints `Bitwise And-ing!`.
+/// In this example, the `BitAnd` trait is implemented for a `BooleanVector`
+/// struct.
 ///
 /// ```
 /// use std::ops::BitAnd;
 ///
-/// struct Foo;
-///
-/// impl BitAnd for Foo {
-///     type Output = Foo;
-///
-///     fn bitand(self, _rhs: Foo) -> Foo {
-///         println!("Bitwise And-ing!");
-///         self
+/// #[derive(Debug)]
+/// struct BooleanVector {
+///     value: Vec<bool>,
+/// };
+///
+/// impl BitAnd for BooleanVector {
+///     type Output = Self;
+///
+///     fn bitand(self, rhs: Self) -> Self {
+///         BooleanVector {
+///             value: self.value
+///                 .iter()
+///                 .zip(rhs.value.iter())
+///                 .map(|(x, y)| *x && *y)
+///                 .collect(),
+///         }
 ///     }
 /// }
 ///
-/// fn main() {
-///     Foo & Foo;
+/// impl PartialEq for BooleanVector {
+///     fn eq(&self, other: &Self) -> bool {
+///         self.value == other.value
+///     }
 /// }
+///
+/// let bv1 = BooleanVector { value: vec![true, true, false, false] };
+/// let bv2 = BooleanVector { value: vec![true, false, true, false] };
+/// let expected = BooleanVector { value: vec![true, false, false, false] };
+/// assert_eq!(bv1 & bv2, expected);
 /// ```
 #[lang = "bitand"]
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1490,28 +1550,44 @@ shr_assign_impl_all! { u8 u16 u32 u64 usize i8 i16 i32 i64 isize }
 ///
 /// # Examples
 ///
-/// A trivial implementation of `Index`. When `Foo[Bar]` happens, it ends up
-/// calling `index`, and therefore, `main` prints `Indexing!`.
+/// This example implements `Index` on a read-only `NucleotideCount` container,
+/// enabling individual counts to be retrieved with index syntax.
 ///
 /// ```
 /// use std::ops::Index;
 ///
-/// #[derive(Copy, Clone)]
-/// struct Foo;
-/// struct Bar;
+/// enum Nucleotide {
+///     A,
+///     C,
+///     G,
+///     T,
+/// }
 ///
-/// impl Index<Bar> for Foo {
-///     type Output = Foo;
+/// struct NucleotideCount {
+///     a: usize,
+///     c: usize,
+///     g: usize,
+///     t: usize,
+/// }
 ///
-///     fn index<'a>(&'a self, _index: Bar) -> &'a Foo {
-///         println!("Indexing!");
-///         self
+/// impl Index<Nucleotide> for NucleotideCount {
+///     type Output = usize;
+///
+///     fn index(&self, nucleotide: Nucleotide) -> &usize {
+///         match nucleotide {
+///             Nucleotide::A => &self.a,
+///             Nucleotide::C => &self.c,
+///             Nucleotide::G => &self.g,
+///             Nucleotide::T => &self.t,
+///         }
 ///     }
 /// }
 ///
-/// fn main() {
-///     Foo[Bar];
-/// }
+/// let nucleotide_count = NucleotideCount {a: 14, c: 9, g: 10, t: 12};
+/// assert_eq!(nucleotide_count[Nucleotide::A], 14);
+/// assert_eq!(nucleotide_count[Nucleotide::C], 9);
+/// assert_eq!(nucleotide_count[Nucleotide::G], 10);
+/// assert_eq!(nucleotide_count[Nucleotide::T], 12);
 /// ```
 #[lang = "index"]
 #[rustc_on_unimplemented = "the type `{Self}` cannot be indexed by `{Idx}`"]

src/libcore/ptr.rs

@@ -128,7 +128,9 @@ pub unsafe fn replace<T>(dest: *mut T, mut src: T) -> T {
 /// let x = 12;
 /// let y = &x as *const i32;
 ///
-/// unsafe { println!("{}", std::ptr::read(y)); }
+/// unsafe {
+///     assert_eq!(std::ptr::read(y), 12);
+/// }
 /// ```
 #[inline(always)]
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -178,7 +180,7 @@ pub unsafe fn read_and_drop<T>(dest: *mut T) -> T {
 ///
 /// unsafe {
 ///     std::ptr::write(y, z);
-///     println!("{}", std::ptr::read(y));
+///     assert_eq!(std::ptr::read(y), 12);
 /// }
 /// ```
 #[inline]
@@ -220,7 +222,9 @@ pub unsafe fn write<T>(dst: *mut T, src: T) {
 /// let x = 12;
 /// let y = &x as *const i32;
 ///
-/// unsafe { println!("{}", std::ptr::read_volatile(y)); }
+/// unsafe {
+///     assert_eq!(std::ptr::read_volatile(y), 12);
+/// }
 /// ```
 #[inline]
 #[stable(feature = "volatile", since = "1.9.0")]
@@ -266,7 +270,7 @@ pub unsafe fn read_volatile<T>(src: *const T) -> T {
 ///
 /// unsafe {
 ///     std::ptr::write_volatile(y, z);
-///     println!("{}", std::ptr::read_volatile(y));
+///     assert_eq!(std::ptr::read_volatile(y), 12);
 /// }
 /// ```
 #[inline]

src/librustc/middle/privacy.rs

@@ -23,9 +23,8 @@ use syntax::ast::NodeId;
 pub enum AccessLevel {
     // Exported items + items participating in various kinds of public interfaces,
     // but not directly nameable. For example, if function `fn f() -> T {...}` is
-    // public, then type `T` is exported. Its values can be obtained by other crates
-    // even if the type itseld is not nameable.
-    // FIXME: Mostly unimplemented. Only `type` aliases export items currently.
+    // public, then type `T` is reachable. Its values can be obtained by other crates
+    // even if the type itself is not nameable.
     Reachable,
     // Public items + items accessible to other crates with help of `pub use` reexports
     Exported,

src/librustc_borrowck/borrowck/check_loans.rs

@@ -647,10 +647,13 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
                 struct_span_err!(self.bccx, span, E0503,
                                  "cannot use `{}` because it was mutably borrowed",
                                  &self.bccx.loan_path_to_string(copy_path))
-                    .span_note(loan_span,
+                    .span_label(loan_span,
                                &format!("borrow of `{}` occurs here",
                                        &self.bccx.loan_path_to_string(&loan_path))
                                )
+                    .span_label(span,
+                               &format!("use of borrowed `{}`",
+                                        &self.bccx.loan_path_to_string(&loan_path)))
                     .emit();
             }
         }

src/librustc_borrowck/borrowck/mod.rs

@@ -914,9 +914,11 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
             }
             mc::AliasableStatic |
             mc::AliasableStaticMut => {
-                struct_span_err!(
+                let mut err = struct_span_err!(
                     self.tcx.sess, span, E0388,
-                    "{} in a static location", prefix)
+                    "{} in a static location", prefix);
+                err.span_label(span, &format!("cannot write data in a static definition"));
+                err
             }
             mc::AliasableBorrowed => {
                 struct_span_err!(