Auto merge of #38214 - GuillaumeGomez:rollup, r=GuillaumeGomez

Rollup of 9 pull requests

- Successful merges: #38085, #38123, #38151, #38153, #38158, #38163, #38186, #38189, #38208
- Failed merges:

4 files changed, 117 insertions, 3 deletions

diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index 368604ccb82..0b310eb2585 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -2117,6 +2117,10 @@ impl DefaultHasher {
 
 #[stable(feature = "hashmap_default_hasher", since = "1.13.0")]
 impl Default for DefaultHasher {
+    /// Creates a new `DefaultHasher` using [`DefaultHasher::new`]. See
+    /// [`DefaultHasher::new`] documentation for more information.
+    ///
+    /// [`DefaultHasher::new`]: #method.new
     fn default() -> DefaultHasher {
         DefaultHasher::new()
     }
diff --git a/src/libstd/panicking.rs b/src/libstd/panicking.rs
index 04050a5edc4..45a10d24528 100644
--- a/src/libstd/panicking.rs
+++ b/src/libstd/panicking.rs
@@ -159,6 +159,23 @@ pub fn take_hook() -> Box<Fn(&PanicInfo) + 'static + Sync + Send> {
 }
 
 /// A struct providing information about a panic.
+///
+/// `PanicInfo` structure is passed to a panic hook set by the [`set_hook()`]
+/// function.
+///
+/// [`set_hook()`]: ../../std/panic/fn.set_hook.html
+///
+/// # Examples
+///
+/// ```should_panic
+/// use std::panic;
+///
+/// panic::set_hook(Box::new(|panic_info| {
+///     println!("panic occured: {:?}", panic_info.payload().downcast_ref::<&str>().unwrap());
+/// }));
+///
+/// panic!("Normal panic");
+/// ```
 #[stable(feature = "panic_hooks", since = "1.10.0")]
 pub struct PanicInfo<'a> {
     payload: &'a (Any + Send),
@@ -168,7 +185,21 @@ pub struct PanicInfo<'a> {
 impl<'a> PanicInfo<'a> {
     /// Returns the payload associated with the panic.
     ///
-    /// This will commonly, but not always, be a `&'static str` or `String`.
+    /// This will commonly, but not always, be a `&'static str` or [`String`].
+    ///
+    /// [`String`]: ../../std/string/struct.String.html
+    ///
+    /// # Examples
+    ///
+    /// ```should_panic
+    /// use std::panic;
+    ///
+    /// panic::set_hook(Box::new(|panic_info| {
+    ///     println!("panic occured: {:?}", panic_info.payload().downcast_ref::<&str>().unwrap());
+    /// }));
+    ///
+    /// panic!("Normal panic");
+    /// ```
     #[stable(feature = "panic_hooks", since = "1.10.0")]
     pub fn payload(&self) -> &(Any + Send) {
         self.payload
@@ -177,8 +208,26 @@ impl<'a> PanicInfo<'a> {
     /// Returns information about the location from which the panic originated,
     /// if available.
     ///
-    /// This method will currently always return `Some`, but this may change
+    /// This method will currently always return [`Some`], but this may change
     /// in future versions.
+    ///
+    /// [`Some`]: ../../std/option/enum.Option.html#variant.Some
+    ///
+    /// # Examples
+    ///
+    /// ```should_panic
+    /// use std::panic;
+    ///
+    /// panic::set_hook(Box::new(|panic_info| {
+    ///     if let Some(location) = panic_info.location() {
+    ///         println!("panic occured in file '{}' at line {}", location.file(), location.line());
+    ///     } else {
+    ///         println!("panic occured but can't get location information...");
+    ///     }
+    /// }));
+    ///
+    /// panic!("Normal panic");
+    /// ```
     #[stable(feature = "panic_hooks", since = "1.10.0")]
     pub fn location(&self) -> Option<&Location> {
         Some(&self.location)
@@ -186,6 +235,27 @@ impl<'a> PanicInfo<'a> {
 }
 
 /// A struct containing information about the location of a panic.
+///
+/// This structure is created by the [`location()`] method of [`PanicInfo`].
+///
+/// [`location()`]: ../../std/panic/struct.PanicInfo.html#method.location
+/// [`PanicInfo`]: ../../std/panic/struct.PanicInfo.html
+///
+/// # Examples
+///
+/// ```should_panic
+/// use std::panic;
+///
+/// panic::set_hook(Box::new(|panic_info| {
+///     if let Some(location) = panic_info.location() {
+///         println!("panic occured in file '{}' at line {}", location.file(), location.line());
+///     } else {
+///         println!("panic occured but can't get location information...");
+///     }
+/// }));
+///
+/// panic!("Normal panic");
+/// ```
 #[stable(feature = "panic_hooks", since = "1.10.0")]
 pub struct Location<'a> {
     file: &'a str,
@@ -194,12 +264,44 @@ pub struct Location<'a> {
 
 impl<'a> Location<'a> {
     /// Returns the name of the source file from which the panic originated.
+    ///
+    /// # Examples
+    ///
+    /// ```should_panic
+    /// use std::panic;
+    ///
+    /// panic::set_hook(Box::new(|panic_info| {
+    ///     if let Some(location) = panic_info.location() {
+    ///         println!("panic occured in file '{}'", location.file());
+    ///     } else {
+    ///         println!("panic occured but can't get location information...");
+    ///     }
+    /// }));
+    ///
+    /// panic!("Normal panic");
+    /// ```
     #[stable(feature = "panic_hooks", since = "1.10.0")]
     pub fn file(&self) -> &str {
         self.file
     }
 
     /// Returns the line number from which the panic originated.
+    ///
+    /// # Examples
+    ///
+    /// ```should_panic
+    /// use std::panic;
+    ///
+    /// panic::set_hook(Box::new(|panic_info| {
+    ///     if let Some(location) = panic_info.location() {
+    ///         println!("panic occured at line {}", location.line());
+    ///     } else {
+    ///         println!("panic occured but can't get location information...");
+    ///     }
+    /// }));
+    ///
+    /// panic!("Normal panic");
+    /// ```
     #[stable(feature = "panic_hooks", since = "1.10.0")]
     pub fn line(&self) -> u32 {
         self.line
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index bfc36d5b21f..858537dd2de 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -827,6 +827,14 @@ impl Child {
 /// will be run. If a clean shutdown is needed it is recommended to only call
 /// this function at a known point where there are no more destructors left
 /// to run.
+///
+/// # Examples
+///
+/// ```
+/// use std::process;
+///
+/// process::exit(0);
+/// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn exit(code: i32) -> ! {
     ::sys_common::cleanup();
diff --git a/src/libstd/sys/unix/ext/io.rs b/src/libstd/sys/unix/ext/io.rs
index 4163ede46af..296235e173d 100644
--- a/src/libstd/sys/unix/ext/io.rs
+++ b/src/libstd/sys/unix/ext/io.rs
@@ -43,7 +43,7 @@ pub trait AsRawFd {
 /// descriptor.
 #[stable(feature = "from_raw_os", since = "1.1.0")]
 pub trait FromRawFd {
-    /// Constructs a new instances of `Self` from the given raw file
+    /// Constructs a new instance of `Self` from the given raw file
     /// descriptor.
     ///
     /// This function **consumes ownership** of the specified file