Auto merge of #75653 - JohnTitor:rollup-0ejtdfo, r=JohnTitor

Rollup of 8 pull requests

Successful merges:

 - #75389 (attempt to improve span_label docs)
 - #75392 (Add `as_uninit`-like methods to pointer types and unify documentation of `as_ref` methods)
 - #75464 (Move to intra doc links for ascii.rs and panic.rs)
 - #75578 (Allowing raw ptr dereference in const fn)
 - #75613 (Add explanation for `&mut self` method call when expecting `-> Self`)
 - #75626 (Clean up E0754 explanation)
 - #75629 (Use intra-doc links in `std::env`, `std::alloc` and `std::error`)
 - #75634 (Mark x86_64-linux-kernel as *)

Failed merges:

r? @ghost

5 files changed, 23 insertions, 95 deletions

diff --git a/library/std/src/alloc.rs b/library/std/src/alloc.rs
index 4712cc95b4a..37a8f514aa1 100644
--- a/library/std/src/alloc.rs
+++ b/library/std/src/alloc.rs
@@ -7,8 +7,6 @@
 //! like `cdylib`s and `staticlib`s are guaranteed to use the [`System`] by
 //! default.
 //!
-//! [`System`]: struct.System.html
-//!
 //! # The `#[global_allocator]` attribute
 //!
 //! This attribute allows configuring the choice of global allocator.
@@ -43,8 +41,6 @@
 //! The attribute is used on a `static` item whose type implements the
 //! [`GlobalAlloc`] trait. This type can be provided by an external library:
 //!
-//! [`GlobalAlloc`]: ../../core/alloc/trait.GlobalAlloc.html
-//!
 //! ```rust,ignore (demonstrates crates.io usage)
 //! extern crate jemallocator;
 //!
@@ -284,9 +280,6 @@ static HOOK: AtomicPtr<()> = AtomicPtr::new(ptr::null_mut());
 /// about the allocation that failed.
 ///
 /// The allocation error hook is a global resource.
-///
-/// [`set_alloc_error_hook`]: fn.set_alloc_error_hook.html
-/// [`take_alloc_error_hook`]: fn.take_alloc_error_hook.html
 #[unstable(feature = "alloc_error_hook", issue = "51245")]
 pub fn set_alloc_error_hook(hook: fn(Layout)) {
     HOOK.store(hook as *mut (), Ordering::SeqCst);
@@ -297,8 +290,6 @@ pub fn set_alloc_error_hook(hook: fn(Layout)) {
 /// *See also the function [`set_alloc_error_hook`].*
 ///
 /// If no custom hook is registered, the default hook will be returned.
-///
-/// [`set_alloc_error_hook`]: fn.set_alloc_error_hook.html
 #[unstable(feature = "alloc_error_hook", issue = "51245")]
 pub fn take_alloc_error_hook() -> fn(Layout) {
     let hook = HOOK.swap(ptr::null_mut(), Ordering::SeqCst);
diff --git a/library/std/src/ascii.rs b/library/std/src/ascii.rs
index 5cd2a25b117..c9106136d34 100644
--- a/library/std/src/ascii.rs
+++ b/library/std/src/ascii.rs
@@ -10,9 +10,6 @@
 //!
 //! The [`escape_default`] function provides an iterator over the bytes of an
 //! escaped version of the character given.
-//!
-//! [`AsciiExt`]: trait.AsciiExt.html
-//! [`escape_default`]: fn.escape_default.html
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
@@ -52,7 +49,7 @@ pub trait AsciiExt {
     ///
     /// # Note
     ///
-    /// This method will be deprecated in favor of the identically-named
+    /// This method is deprecated in favor of the identically-named
     /// inherent methods on `u8`, `char`, `[u8]` and `str`.
     #[stable(feature = "rust1", since = "1.0.0")]
     fn is_ascii(&self) -> bool;
@@ -69,10 +66,10 @@ pub trait AsciiExt {
     ///
     /// # Note
     ///
-    /// This method will be deprecated in favor of the identically-named
+    /// This method is deprecated in favor of the identically-named
     /// inherent methods on `u8`, `char`, `[u8]` and `str`.
     ///
-    /// [`make_ascii_uppercase`]: #tymethod.make_ascii_uppercase
+    /// [`make_ascii_uppercase`]: AsciiExt::make_ascii_uppercase
     /// [`str::to_uppercase`]: ../primitive.str.html#method.to_uppercase
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow(deprecated)]
@@ -90,10 +87,10 @@ pub trait AsciiExt {
     ///
     /// # Note
     ///
-    /// This method will be deprecated in favor of the identically-named
+    /// This method is deprecated in favor of the identically-named
     /// inherent methods on `u8`, `char`, `[u8]` and `str`.
     ///
-    /// [`make_ascii_lowercase`]: #tymethod.make_ascii_lowercase
+    /// [`make_ascii_lowercase`]: AsciiExt::make_ascii_lowercase
     /// [`str::to_lowercase`]: ../primitive.str.html#method.to_lowercase
     #[stable(feature = "rust1", since = "1.0.0")]
     #[allow(deprecated)]
@@ -106,7 +103,7 @@ pub trait AsciiExt {
     ///
     /// # Note
     ///
-    /// This method will be deprecated in favor of the identically-named
+    /// This method is deprecated in favor of the identically-named
     /// inherent methods on `u8`, `char`, `[u8]` and `str`.
     #[stable(feature = "rust1", since = "1.0.0")]
     fn eq_ignore_ascii_case(&self, other: &Self) -> bool;
@@ -121,10 +118,10 @@ pub trait AsciiExt {
     ///
     /// # Note
     ///
-    /// This method will be deprecated in favor of the identically-named
+    /// This method is deprecated in favor of the identically-named
     /// inherent methods on `u8`, `char`, `[u8]` and `str`.
     ///
-    /// [`to_ascii_uppercase`]: #tymethod.to_ascii_uppercase
+    /// [`to_ascii_uppercase`]: AsciiExt::to_ascii_uppercase
     #[stable(feature = "ascii", since = "1.9.0")]
     fn make_ascii_uppercase(&mut self);
 
@@ -138,10 +135,10 @@ pub trait AsciiExt {
     ///
     /// # Note
     ///
-    /// This method will be deprecated in favor of the identically-named
+    /// This method is deprecated in favor of the identically-named
     /// inherent methods on `u8`, `char`, `[u8]` and `str`.
     ///
-    /// [`to_ascii_lowercase`]: #tymethod.to_ascii_lowercase
+    /// [`to_ascii_lowercase`]: AsciiExt::to_ascii_lowercase
     #[stable(feature = "ascii", since = "1.9.0")]
     fn make_ascii_lowercase(&mut self);
 }
diff --git a/library/std/src/env.rs b/library/std/src/env.rs
index 6489e0709cb..387c588f4a0 100644
--- a/library/std/src/env.rs
+++ b/library/std/src/env.rs
@@ -7,9 +7,6 @@
 //! There are several functions and structs in this module that have a
 //! counterpart ending in `os`. Those ending in `os` will return an [`OsString`]
 //! and those without will return a [`String`].
-//!
-//! [`OsString`]: ../../std/ffi/struct.OsString.html
-//! [`String`]: ../string/struct.String.html
 
 #![stable(feature = "env", since = "1.0.0")]
 
@@ -31,9 +28,6 @@ use crate::sys::os as os_imp;
 /// * Current directory does not exist.
 /// * There are insufficient permissions to access the current directory.
 ///
-/// [`PathBuf`]: ../../std/path/struct.PathBuf.html
-/// [`Err`]: ../../std/result/enum.Result.html#method.err
-///
 /// # Examples
 ///
 /// ```
@@ -54,8 +48,6 @@ pub fn current_dir() -> io::Result<PathBuf> {
 ///
 /// Returns an [`Err`] if the operation fails.
 ///
-/// [`Err`]: ../../std/result/enum.Result.html#method.err
-///
 /// # Examples
 ///
 /// ```
@@ -76,7 +68,7 @@ pub fn set_current_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
 /// This structure is created by the [`std::env::vars`] function. See its
 /// documentation for more.
 ///
-/// [`std::env::vars`]: fn.vars.html
+/// [`std::env::vars`]: vars
 #[stable(feature = "env", since = "1.0.0")]
 pub struct Vars {
     inner: VarsOs,
@@ -87,7 +79,7 @@ pub struct Vars {
 /// This structure is created by the [`std::env::vars_os`] function. See
 /// its documentation for more.
 ///
-/// [`std::env::vars_os`]: fn.vars_os.html
+/// [`std::env::vars_os`]: vars_os
 #[stable(feature = "env", since = "1.0.0")]
 pub struct VarsOs {
     inner: os_imp::Env,
@@ -106,7 +98,7 @@ pub struct VarsOs {
 /// environment is not valid unicode. If this is not desired, consider using the
 /// [`env::vars_os`] function.
 ///
-/// [`env::vars_os`]: fn.vars_os.html
+/// [`env::vars_os`]: vars_os
 ///
 /// # Examples
 ///
@@ -222,8 +214,6 @@ fn _var(key: &OsStr) -> Result<String, VarError> {
 /// Fetches the environment variable `key` from the current process, returning
 /// [`None`] if the variable isn't set.
 ///
-/// [`None`]: ../option/enum.Option.html#variant.None
-///
 /// # Panics
 ///
 /// This function may panic if `key` is empty, contains an ASCII equals sign
@@ -254,7 +244,7 @@ fn _var_os(key: &OsStr) -> Option<OsString> {
 /// The error type for operations interacting with environment variables.
 /// Possibly returned from the [`env::var`] function.
 ///
-/// [`env::var`]: fn.var.html
+/// [`env::var`]: var
 #[derive(Debug, PartialEq, Eq, Clone)]
 #[stable(feature = "env", since = "1.0.0")]
 pub enum VarError {
@@ -382,8 +372,7 @@ fn _remove_var(k: &OsStr) {
 /// This structure is created by the [`std::env::split_paths`] function. See its
 /// documentation for more.
 ///
-/// [`PathBuf`]: ../../std/path/struct.PathBuf.html
-/// [`std::env::split_paths`]: fn.split_paths.html
+/// [`std::env::split_paths`]: split_paths
 #[stable(feature = "env", since = "1.0.0")]
 pub struct SplitPaths<'a> {
     inner: os_imp::SplitPaths<'a>,
@@ -410,8 +399,6 @@ pub struct SplitPaths<'a> {
 ///     None => println!("{} is not defined in the environment.", key)
 /// }
 /// ```
-///
-/// [`PathBuf`]: ../../std/path/struct.PathBuf.html
 #[stable(feature = "env", since = "1.0.0")]
 pub fn split_paths<T: AsRef<OsStr> + ?Sized>(unparsed: &T) -> SplitPaths<'_> {
     SplitPaths { inner: os_imp::split_paths(unparsed.as_ref()) }
@@ -438,7 +425,7 @@ impl fmt::Debug for SplitPaths<'_> {
 /// The error type for operations on the `PATH` variable. Possibly returned from
 /// the [`env::join_paths`] function.
 ///
-/// [`env::join_paths`]: fn.join_paths.html
+/// [`env::join_paths`]: join_paths
 #[derive(Debug)]
 #[stable(feature = "env", since = "1.0.0")]
 pub struct JoinPathsError {
@@ -450,14 +437,10 @@ pub struct JoinPathsError {
 ///
 /// # Errors
 ///
-/// Returns an [`Err`][err] (containing an error message) if one of the input
+/// Returns an [`Err`] (containing an error message) if one of the input
 /// [`Path`]s contains an invalid character for constructing the `PATH`
 /// variable (a double quote on Windows or a colon on Unix).
 ///
-/// [`Path`]: ../../std/path/struct.Path.html
-/// [`OsString`]: ../../std/ffi/struct.OsString.html
-/// [err]: ../../std/result/enum.Result.html#variant.Err
-///
 /// # Examples
 ///
 /// Joining paths on a Unix-like platform:
@@ -508,7 +491,7 @@ pub struct JoinPathsError {
 /// }
 /// ```
 ///
-/// [`env::split_paths`]: fn.split_paths.html
+/// [`env::split_paths`]: split_paths
 #[stable(feature = "env", since = "1.0.0")]
 pub fn join_paths<I, T>(paths: I) -> Result<OsString, JoinPathsError>
 where
@@ -688,8 +671,7 @@ pub fn current_exe() -> io::Result<PathBuf> {
 /// set to arbitrary text, and may not even exist. This means this property
 /// should not be relied upon for security purposes.
 ///
-/// [`String`]: ../string/struct.String.html
-/// [`std::env::args`]: ./fn.args.html
+/// [`std::env::args`]: args
 #[stable(feature = "env", since = "1.0.0")]
 pub struct Args {
     inner: ArgsOs,
@@ -705,8 +687,7 @@ pub struct Args {
 /// set to arbitrary text, and may not even exist. This means this property
 /// should not be relied upon for security purposes.
 ///
-/// [`OsString`]: ../ffi/struct.OsString.html
-/// [`std::env::args_os`]: ./fn.args_os.html
+/// [`std::env::args_os`]: args_os
 #[stable(feature = "env", since = "1.0.0")]
 pub struct ArgsOs {
     inner: sys::args::Args,
@@ -744,8 +725,6 @@ pub struct ArgsOs {
 ///     println!("{}", argument);
 /// }
 /// ```
-///
-/// [`args_os`]: ./fn.args_os.html
 #[stable(feature = "env", since = "1.0.0")]
 pub fn args() -> Args {
     Args { inner: args_os() }
diff --git a/library/std/src/error.rs b/library/std/src/error.rs
index 3b4cb859dd4..1b7681bd4bb 100644
--- a/library/std/src/error.rs
+++ b/library/std/src/error.rs
@@ -40,10 +40,8 @@ use crate::string;
 /// provide its own errors while also revealing some of the implementation for
 /// debugging via [`source`] chains.
 ///
-/// [`Result<T, E>`]: ../result/enum.Result.html
-/// [`Display`]: ../fmt/trait.Display.html
-/// [`Debug`]: ../fmt/trait.Debug.html
-/// [`source`]: trait.Error.html#method.source
+/// [`Result<T, E>`]: Result
+/// [`source`]: Error::source
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Error: Debug + Display {
     /// The lower-level source of this error, if any.
@@ -164,8 +162,6 @@ mod private {
 impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> {
     /// Converts a type of [`Error`] into a box of dyn [`Error`].
     ///
-    /// [`Error`]: ../error/trait.Error.html
-    ///
     /// # Examples
     ///
     /// ```
@@ -199,8 +195,6 @@ impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync +
     /// Converts a type of [`Error`] + [`Send`] + [`Sync`] into a box of
     /// dyn [`Error`] + [`Send`] + [`Sync`].
     ///
-    /// [`Error`]: ../error/trait.Error.html
-    ///
     /// # Examples
     ///
     /// ```
@@ -238,8 +232,6 @@ impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync +
 impl From<String> for Box<dyn Error + Send + Sync> {
     /// Converts a [`String`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
     ///
-    /// [`Error`]: ../error/trait.Error.html
-    ///
     /// # Examples
     ///
     /// ```
@@ -283,8 +275,6 @@ impl From<String> for Box<dyn Error + Send + Sync> {
 impl From<String> for Box<dyn Error> {
     /// Converts a [`String`] into a box of dyn [`Error`].
     ///
-    /// [`Error`]: ../error/trait.Error.html
-    ///
     /// # Examples
     ///
     /// ```
@@ -306,8 +296,6 @@ impl From<String> for Box<dyn Error> {
 impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
     /// Converts a [`str`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
     ///
-    /// [`Error`]: ../error/trait.Error.html
-    ///
     /// # Examples
     ///
     /// ```
@@ -329,8 +317,6 @@ impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
 impl From<&str> for Box<dyn Error> {
     /// Converts a [`str`] into a box of dyn [`Error`].
     ///
-    /// [`Error`]: ../error/trait.Error.html
-    ///
     /// # Examples
     ///
     /// ```
@@ -350,9 +336,6 @@ impl From<&str> for Box<dyn Error> {
 impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> {
     /// Converts a [`Cow`] into a box of dyn [`Error`] + [`Send`] + [`Sync`].
     ///
-    /// [`Cow`]: ../borrow/enum.Cow.html
-    /// [`Error`]: ../error/trait.Error.html
-    ///
     /// # Examples
     ///
     /// ```
@@ -374,9 +357,6 @@ impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> {
 impl<'a> From<Cow<'a, str>> for Box<dyn Error> {
     /// Converts a [`Cow`] into a box of dyn [`Error`].
     ///
-    /// [`Cow`]: ../borrow/enum.Cow.html
-    /// [`Error`]: ../error/trait.Error.html
-    ///
     /// # Examples
     ///
     /// ```
@@ -703,7 +683,7 @@ impl dyn Error {
     /// assert!(iter.next().is_none());
     /// ```
     ///
-    /// [`source`]: trait.Error.html#method.source
+    /// [`source`]: Error::source
     #[unstable(feature = "error_iter", issue = "58520")]
     #[inline]
     pub fn chain(&self) -> Chain<'_> {
@@ -715,8 +695,6 @@ impl dyn Error {
 ///
 /// If you want to omit the initial error and only process
 /// its sources, use `skip(1)`.
-///
-/// [`Error`]: trait.Error.html
 #[unstable(feature = "error_iter", issue = "58520")]
 #[derive(Clone, Debug)]
 pub struct Chain<'a> {
diff --git a/library/std/src/panic.rs b/library/std/src/panic.rs
index 6ad5519d34a..8fcb24033b1 100644
--- a/library/std/src/panic.rs
+++ b/library/std/src/panic.rs
@@ -30,10 +30,6 @@ pub use core::panic::{Location, PanicInfo};
 /// purpose of this trait is to encode what types are safe to cross a [`catch_unwind`]
 /// boundary with no fear of unwind safety.
 ///
-/// [`Send`]: ../marker/trait.Send.html
-/// [`Sync`]: ../marker/trait.Sync.html
-/// [`catch_unwind`]: ./fn.catch_unwind.html
-///
 /// ## What is unwind safety?
 ///
 /// In Rust a function can "return" early if it either panics or calls a
@@ -99,8 +95,6 @@ pub use core::panic::{Location, PanicInfo};
 /// above, the lack of `unsafe` means it is mostly an advisory. The
 /// [`AssertUnwindSafe`] wrapper struct can be used to force this trait to be
 /// implemented for any closed over variables passed to `catch_unwind`.
-///
-/// [`AssertUnwindSafe`]: ./struct.AssertUnwindSafe.html
 #[stable(feature = "catch_unwind", since = "1.9.0")]
 #[rustc_on_unimplemented(
     message = "the type `{Self}` may not be safely transferred across an unwind boundary",
@@ -116,9 +110,6 @@ pub auto trait UnwindSafe {}
 ///
 /// This is a "helper marker trait" used to provide impl blocks for the
 /// [`UnwindSafe`] trait, for more information see that documentation.
-///
-/// [`UnsafeCell`]: ../cell/struct.UnsafeCell.html
-/// [`UnwindSafe`]: ./trait.UnwindSafe.html
 #[stable(feature = "catch_unwind", since = "1.9.0")]
 #[rustc_on_unimplemented(
     message = "the type `{Self}` may contain interior mutability and a reference may not be safely \
@@ -138,7 +129,6 @@ pub auto trait RefUnwindSafe {}
 /// account. This wrapper struct is useful for a quick and lightweight
 /// annotation that a variable is indeed unwind safe.
 ///
-/// [`catch_unwind`]: ./fn.catch_unwind.html
 /// # Examples
 ///
 /// One way to use `AssertUnwindSafe` is to assert that the entire closure
@@ -352,8 +342,6 @@ impl<F: Future> Future for AssertUnwindSafe<F> {
 /// can fail on a regular basis. Additionally, this function is not guaranteed
 /// to catch all panics, see the "Notes" section below.
 ///
-/// [`Result`]: ../result/enum.Result.html
-///
 /// The closure provided is required to adhere to the [`UnwindSafe`] trait to ensure
 /// that all captured variables are safe to cross this boundary. The purpose of
 /// this bound is to encode the concept of [exception safety][rfc] in the type
@@ -362,9 +350,6 @@ impl<F: Future> Future for AssertUnwindSafe<F> {
 /// becomes a problem the [`AssertUnwindSafe`] wrapper struct can be used to quickly
 /// assert that the usage here is indeed unwind safe.
 ///
-/// [`AssertUnwindSafe`]: ./struct.AssertUnwindSafe.html
-/// [`UnwindSafe`]: ./trait.UnwindSafe.html
-///
 /// [rfc]: https://github.com/rust-lang/rfcs/blob/master/text/1236-stabilize-catch-panic.md
 ///
 /// # Notes
@@ -399,8 +384,6 @@ pub fn catch_unwind<F: FnOnce() -> R + UnwindSafe, R>(f: F) -> Result<R> {
 /// This is designed to be used in conjunction with [`catch_unwind`] to, for
 /// example, carry a panic across a layer of C code.
 ///
-/// [`catch_unwind`]: ./fn.catch_unwind.html
-///
 /// # Notes
 ///
 /// Note that panics in Rust are not always implemented via unwinding, but they