Auto merge of #25281 - steveklabnik:rollup, r=steveklabnik

- Successful merges: #24948, #25158, #25188, #25222, #25239, #25240, #25241, #25255, #25257, #25263
- Failed merges:

Author: bors

src/doc/trpl/guessing-game.md

@@ -713,7 +713,7 @@ variety of numbers, we need to give Rust a hint as to the exact type of number
 we want. Hence, `let guess: u32`. The colon (`:`) after `guess` tells Rust
 we’re going to annotate its type. `u32` is an unsigned, thirty-two bit
 integer. Rust has [a number of built-in number types][number], but we’ve
-chosen `u32`. It’s a good default choice for a small positive numer.
+chosen `u32`. It’s a good default choice for a small positive number.
 
 [parse]: ../std/primitive.str.html#method.parse
 [number]: primitive-types.html#numeric-types
@@ -922,7 +922,7 @@ failure. Each contains more information: the successful parsed integer, or an
 error type. In this case, we `match` on `Ok(num)`, which sets the inner value
 of the `Ok` to the name `num`, and then we just return it on the right-hand
 side. In the `Err` case, we don’t care what kind of error it is, so we just
-use `_` intead of a name. This ignores the error, and `continue` causes us
+use `_` instead of a name. This ignores the error, and `continue` causes us
 to go to the next iteration of the `loop`.
 
 Now we should be good! Let’s try:

src/doc/trpl/match.md

@@ -50,7 +50,7 @@ side of a `let` binding or directly where an expression is used:
 ```rust
 let x = 5;
 
-let numer = match x {
+let number = match x {
     1 => "one",
     2 => "two",
     3 => "three",

src/doc/trpl/mutability.md

@@ -78,8 +78,8 @@ When we call `clone()`, the `Arc<T>` needs to update the reference count. Yet
 we’ve not used any `mut`s here, `x` is an immutable binding, and we didn’t take
 `&mut 5` or anything. So what gives?
 
-To this, we have to go back to the core of Rust’s guiding philosophy, memory
-safety, and the mechanism by which Rust guarantees it, the
+To understand this, we have to go back to the core of Rust’s guiding
+philosophy, memory safety, and the mechanism by which Rust guarantees it, the
 [ownership][ownership] system, and more specifically, [borrowing][borrowing]:
 
 > You may have one or the other of these two kinds of borrows, but not both at

src/doc/trpl/ownership.md

@@ -174,7 +174,7 @@ fn foo(v: Vec<i32>) -> Vec<i32> {
 }
 ```
 
-This would get very tedius. It gets worse the more things we want to take ownership of:
+This would get very tedious. It gets worse the more things we want to take ownership of:
 
 ```rust
 fn foo(v1: Vec<i32>, v2: Vec<i32>) -> (Vec<i32>, Vec<i32>, i32) {

src/doc/trpl/primitive-types.md

@@ -176,7 +176,7 @@ Slices have type `&[T]`. We’ll talk about that `T` when we cover
 
 [generics]: generics.html
 
-You can find more documentation for `slices`s [in the standard library
+You can find more documentation for slices [in the standard library
 documentation][slice].
 
 [slice]: ../std/primitive.slice.html

src/doc/trpl/references-and-borrowing.md

@@ -312,6 +312,7 @@ println!("{}", y);
 
 We get this error:
 
+```text
 error: `x` does not live long enough
     y = &x;
          ^
@@ -334,3 +335,37 @@ In other words, `y` is only valid for the scope where `x` exists. As soon as
 `x` goes away, it becomes invalid to refer to it. As such, the error says that
 the borrow ‘doesn’t live long enough’ because it’s not valid for the right
 amount of time.
+
+The same problem occurs when the reference is declared _before_ the variable it refers to:
+
+```rust,ignore
+let y: &i32;
+let x = 5;
+y = &x;
+
+println!("{}", y);
+```
+
+We get this error:
+
+```text
+error: `x` does not live long enough
+y = &x;
+     ^
+note: reference must be valid for the block suffix following statement 0 at
+2:16...
+    let y: &i32;
+    let x = 5;
+    y = &x;
+    
+    println!("{}", y);
+}
+
+note: ...but borrowed value is only valid for the block suffix following
+statement 1 at 3:14
+    let x = 5;
+    y = &x;
+    
+    println!("{}", y);
+}
+```

src/etc/CONFIGS.md

@@ -1,10 +1,16 @@
 # Configs
 
-Here are some links to repos with configs which ease the use of rust:
+These are some links to repos with configs which ease the use of rust.
+
+## Officially Maintained Configs
 
 * [rust.vim](https://github.com/rust-lang/rust.vim)
 * [emacs rust-mode](https://github.com/rust-lang/rust-mode)
 * [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)
 * [zsh-config](https://github.com/rust-lang/zsh-config)
+
+## Community-maintained Configs
+
+* [.editorconfig](https://gist.github.com/derhuerst/c9d1b9309e308d9851fa) ([what is this?](http://editorconfig.org/))

src/libcollections/string.rs

@@ -1052,6 +1052,7 @@ impl<T: fmt::Display + ?Sized> ToString for T {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<str> for String {
+    #[inline]
     fn as_ref(&self) -> &str {
         self
     }

src/libcore/convert.rs

@@ -173,6 +173,7 @@ impl<T> AsMut<[T]> for [T] {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<str> for str {
+    #[inline]
     fn as_ref(&self) -> &str {
         self
     }

src/librustc_typeck/diagnostics.rs

@@ -46,6 +46,23 @@ enum variant, one of the fields was not provided. Each field should be specified
 exactly once.
 "##,
 
+E0067: r##"
+The left-hand side of an assignment operator must be an lvalue expression. An
+lvalue expression represents a memory location and includes item paths (ie,
+namespaced variables), dereferences, indexing expressions, and field references.
+
+```
+use std::collections::LinkedList;
+
+// Good
+let mut list = LinkedList::new();
+
+
+// Bad: assignment to non-lvalue expression
+LinkedList::new() += 1;
+```
+"##,
+
 E0081: r##"
 Enum discriminants are used to differentiate enum variants stored in memory.
 This error indicates that the same value was used for two or more variants,
@@ -119,6 +136,20 @@ construct an instance of the following type using only safe code:
 ```
 enum Empty {}
 ```
+"##,
+
+E0131: r##"
+It is not possible to define `main` with type parameters, or even with function
+parameters. When `main` is present, it must take no arguments and return `()`.
+"##,
+
+E0132: r##"
+It is not possible to declare type parameters on a function that has the `start`
+attribute. Such a function must have the following type signature:
+
+```
+fn(isize, *const *const u8) -> isize
+```
 "##
 
 }
@@ -149,7 +180,6 @@ register_diagnostics! {
     E0060,
     E0061,
     E0066,
-    E0067,
     E0068,
     E0069,
     E0070,
@@ -189,8 +219,6 @@ register_diagnostics! {
     E0128,
     E0129,
     E0130,
-    E0131,
-    E0132,
     E0141,
     E0159,
     E0163,

src/libstd/collections/hash/map.rs

@@ -916,6 +916,24 @@ impl<K, V, S> HashMap<K, V, S>
     }
 
     /// Gets the given key's corresponding entry in the map for in-place manipulation.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::collections::HashMap;
+    ///
+    /// let mut letters = HashMap::new();
+    ///
+    /// for ch in "a short treatise on fungi".chars() {
+    ///     let counter = letters.entry(ch).or_insert(0);
+    ///     *counter += 1;
+    /// }
+    ///
+    /// assert_eq!(letters[&'s'], 2);
+    /// assert_eq!(letters[&'t'], 3);
+    /// assert_eq!(letters[&'u'], 1);
+    /// assert_eq!(letters.get(&'y'), None);
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn entry(&mut self, key: K) -> Entry<K, V> {
         // Gotta resize now.