Auto merge of #34778 - GuillaumeGomez:rollup, r=GuillaumeGomez

Rollup of 7 pull requests

- Successful merges: #34736, #34737, #34740, #34742, #34749, #34750, #34770
- Failed merges: #33951

Author: bors

src/doc/book/closures.md

@@ -336,7 +336,7 @@ could annotate it on the function declaration:
 
 ```rust,ignore
 fn call_with_ref<'a, F>(some_closure:F) -> i32
-    where F: Fn(&'a 32) -> i32 {
+    where F: Fn(&'a i32) -> i32 {
 ```
 
 However this presents a problem with in our case. When you specify the explicit
@@ -350,7 +350,7 @@ of the closure we can use Higher-Ranked Trait Bounds with the `for<...>` syntax:
 
 ```ignore
 fn call_with_ref<F>(some_closure:F) -> i32
-    where F: for<'a> Fn(&'a 32) -> i32 {
+    where F: for<'a> Fn(&'a i32) -> i32 {
 ```
 
 This lets the Rust compiler find the minimum lifetime to invoke our closure and

src/doc/reference.md

@@ -2633,7 +2633,7 @@ comma:
 
 There are several forms of struct expressions. A _struct expression_
 consists of the [path](#paths) of a [struct item](#structs), followed by
-a brace-enclosed list of one or more comma-separated name-value pairs,
+a brace-enclosed list of zero or more comma-separated name-value pairs,
 providing the field values of a new instance of the struct. A field name
 can be any identifier, and is separated from its value expression by a colon.
 The location denoted by a struct field is mutable if and only if the
@@ -2652,10 +2652,12 @@ The following are examples of struct expressions:
 
 ```
 # struct Point { x: f64, y: f64 }
+# struct NothingInMe { }
 # struct TuplePoint(f64, f64);
 # mod game { pub struct User<'a> { pub name: &'a str, pub age: u32, pub score: usize } }
 # struct Cookie; fn some_fn<T>(t: T) {}
 Point {x: 10.0, y: 20.0};
+NothingInMe {};
 TuplePoint(10.0, 20.0);
 let u = game::User {name: "Joe", age: 35, score: 100_000};
 some_fn::<Cookie>(Cookie);

src/liballoc/boxed.rs

@@ -249,6 +249,14 @@ impl<T: ?Sized> Box<T> {
     /// This function is unsafe because improper use may lead to
     /// memory problems. For example, a double-free may occur if the
     /// function is called twice on the same raw pointer.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let x = Box::new(5);
+    /// let ptr = Box::into_raw(x);
+    /// let x = unsafe { Box::from_raw(ptr) };
+    /// ```
     #[stable(feature = "box_raw", since = "1.4.0")]
     #[inline]
     pub unsafe fn from_raw(raw: *mut T) -> Self {
@@ -266,9 +274,8 @@ impl<T: ?Sized> Box<T> {
     /// # Examples
     ///
     /// ```
-    /// let seventeen = Box::new(17);
-    /// let raw = Box::into_raw(seventeen);
-    /// let boxed_again = unsafe { Box::from_raw(raw) };
+    /// let x = Box::new(5);
+    /// let ptr = Box::into_raw(x);
     /// ```
     #[stable(feature = "box_raw", since = "1.4.0")]
     #[inline]
@@ -399,6 +406,24 @@ impl Box<Any> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     /// Attempt to downcast the box to a concrete type.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn print_if_string(value: Box<Any>) {
+    ///     if let Ok(string) = value.downcast::<String>() {
+    ///         println!("String ({}): {}", string.len(), string);
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     let my_string = "Hello World".to_string();
+    ///     print_if_string(Box::new(my_string));
+    ///     print_if_string(Box::new(0i8));
+    /// }
+    /// ```
     pub fn downcast<T: Any>(self) -> Result<Box<T>, Box<Any>> {
         if self.is::<T>() {
             unsafe {
@@ -419,6 +444,24 @@ impl Box<Any + Send> {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     /// Attempt to downcast the box to a concrete type.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn print_if_string(value: Box<Any + Send>) {
+    ///     if let Ok(string) = value.downcast::<String>() {
+    ///         println!("String ({}): {}", string.len(), string);
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     let my_string = "Hello World".to_string();
+    ///     print_if_string(Box::new(my_string));
+    ///     print_if_string(Box::new(0i8));
+    /// }
+    /// ```
     pub fn downcast<T: Any>(self) -> Result<Box<T>, Box<Any + Send>> {
         <Box<Any>>::downcast(self).map_err(|s| unsafe {
             // reapply the Send marker

src/libcore/any.rs

@@ -92,6 +92,23 @@ use marker::{Reflect, Sized};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Any: Reflect + 'static {
     /// Gets the `TypeId` of `self`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(get_type_id)]
+    ///
+    /// use std::any::{Any, TypeId};
+    ///
+    /// fn is_string(s: &Any) -> bool {
+    ///     TypeId::of::<String>() == s.get_type_id()
+    /// }
+    ///
+    /// fn main() {
+    ///     assert_eq!(is_string(&0), false);
+    ///     assert_eq!(is_string(&"cookie monster".to_owned()), true);
+    /// }
+    /// ```
     #[unstable(feature = "get_type_id",
                reason = "this method will likely be replaced by an associated static",
                issue = "27745")]
@@ -125,7 +142,26 @@ impl fmt::Debug for Any + Send {
 }
 
 impl Any {
-    /// Returns true if the boxed type is the same as `T`
+    /// Returns true if the boxed type is the same as `T`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn is_string(s: &Any) {
+    ///     if s.is::<String>() {
+    ///         println!("It's a string!");
+    ///     } else {
+    ///         println!("Not a string...");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     is_string(&0);
+    ///     is_string(&"cookie monster".to_owned());
+    /// }
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is<T: Any>(&self) -> bool {
@@ -141,6 +177,25 @@ impl Any {
 
     /// Returns some reference to the boxed value if it is of type `T`, or
     /// `None` if it isn't.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn print_if_string(s: &Any) {
+    ///     if let Some(string) = s.downcast_ref::<String>() {
+    ///         println!("It's a string({}): '{}'", string.len(), string);
+    ///     } else {
+    ///         println!("Not a string...");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     print_if_string(&0);
+    ///     print_if_string(&"cookie monster".to_owned());
+    /// }
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn downcast_ref<T: Any>(&self) -> Option<&T> {
@@ -159,6 +214,29 @@ impl Any {
 
     /// Returns some mutable reference to the boxed value if it is of type `T`, or
     /// `None` if it isn't.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn modify_if_u32(s: &mut Any) {
+    ///     if let Some(num) = s.downcast_mut::<u32>() {
+    ///         *num = 42;
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     let mut x = 10u32;
+    ///     let mut s = "starlord".to_owned();
+    ///
+    ///     modify_if_u32(&mut x);
+    ///     modify_if_u32(&mut s);
+    ///
+    ///     assert_eq!(x, 42);
+    ///     assert_eq!(&s, "starlord");
+    /// }
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
@@ -178,20 +256,81 @@ impl Any {
 
 impl Any+Send {
     /// Forwards to the method defined on the type `Any`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn is_string(s: &(Any + Send)) {
+    ///     if s.is::<String>() {
+    ///         println!("It's a string!");
+    ///     } else {
+    ///         println!("Not a string...");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     is_string(&0);
+    ///     is_string(&"cookie monster".to_owned());
+    /// }
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn is<T: Any>(&self) -> bool {
         Any::is::<T>(self)
     }
 
     /// Forwards to the method defined on the type `Any`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn print_if_string(s: &(Any + Send)) {
+    ///     if let Some(string) = s.downcast_ref::<String>() {
+    ///         println!("It's a string({}): '{}'", string.len(), string);
+    ///     } else {
+    ///         println!("Not a string...");
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     print_if_string(&0);
+    ///     print_if_string(&"cookie monster".to_owned());
+    /// }
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn downcast_ref<T: Any>(&self) -> Option<&T> {
         Any::downcast_ref::<T>(self)
     }
 
     /// Forwards to the method defined on the type `Any`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn modify_if_u32(s: &mut (Any+ Send)) {
+    ///     if let Some(num) = s.downcast_mut::<u32>() {
+    ///         *num = 42;
+    ///     }
+    /// }
+    ///
+    /// fn main() {
+    ///     let mut x = 10u32;
+    ///     let mut s = "starlord".to_owned();
+    ///
+    ///     modify_if_u32(&mut x);
+    ///     modify_if_u32(&mut s);
+    ///
+    ///     assert_eq!(x, 42);
+    ///     assert_eq!(&s, "starlord");
+    /// }
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
@@ -220,7 +359,24 @@ pub struct TypeId {
 
 impl TypeId {
     /// Returns the `TypeId` of the type this generic function has been
-    /// instantiated with
+    /// instantiated with.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(get_type_id)]
+    ///
+    /// use std::any::{Any, TypeId};
+    ///
+    /// fn is_string(s: &Any) -> bool {
+    ///     TypeId::of::<String>() == s.get_type_id()
+    /// }
+    ///
+    /// fn main() {
+    ///     assert_eq!(is_string(&0), false);
+    ///     assert_eq!(is_string(&"cookie monster".to_owned()), true);
+    /// }
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn of<T: ?Sized + Reflect + 'static>() -> TypeId {
         TypeId {