Auto merge of rust-lang#75715 - tmandry:rollup-18atkj4, r=tmandry

Rollup of 7 pull requests

Successful merges:

 - rust-lang#75069 (move const param structural match checks to wfcheck)
 - rust-lang#75587 (mir building: fix some comments)
 - rust-lang#75593 (Adjust installation place for compiler docs)
 - rust-lang#75648 (Make OnceCell<T> transparent to dropck)
 - rust-lang#75649 (Fix intra-doc links for inherent impls that are both lang items and not the default impl)
 - rust-lang#75674 (Move to intra doc links for std::io)
 - rust-lang#75696 (Remove `#[cfg(miri)]` from OnceCell tests)

Failed merges:

r? @ghost

Cargo.lock

@@ -4106,6 +4106,7 @@ dependencies = [
  "rustc-rayon",
  "serde",
  "serde_json",
+ "smallvec 1.4.2",
  "tempfile",
 ]
 

library/core/tests/lazy.rs

@@ -122,3 +122,12 @@ fn reentrant_init() {
     });
     eprintln!("use after free: {:?}", dangling_ref.get().unwrap());
 }
+
+#[test]
+fn dropck() {
+    let cell = OnceCell::new();
+    {
+        let s = String::new();
+        cell.set(&s).unwrap();
+    }
+}

library/std/src/io/buffered.rs

@@ -21,17 +21,16 @@ use crate::memchr;
 /// *repeated* read calls to the same file or network socket. It does not
 /// help when reading very large amounts at once, or reading just one or a few
 /// times. It also provides no advantage when reading from a source that is
-/// already in memory, like a `Vec<u8>`.
+/// already in memory, like a [`Vec`]`<u8>`.
 ///
 /// When the `BufReader<R>` is dropped, the contents of its buffer will be
 /// discarded. Creating multiple instances of a `BufReader<R>` on the same
 /// stream can cause data loss. Reading from the underlying reader after
-/// unwrapping the `BufReader<R>` with `BufReader::into_inner` can also cause
+/// unwrapping the `BufReader<R>` with [`BufReader::into_inner`] can also cause
 /// data loss.
 ///
-/// [`Read`]: ../../std/io/trait.Read.html
-/// [`TcpStream::read`]: ../../std/net/struct.TcpStream.html#method.read
-/// [`TcpStream`]: ../../std/net/struct.TcpStream.html
+/// [`TcpStream::read`]: Read::read
+/// [`TcpStream`]: crate::net::TcpStream
 ///
 /// # Examples
 ///
@@ -155,7 +154,9 @@ impl<R> BufReader<R> {
 
     /// Returns a reference to the internally buffered data.
     ///
-    /// Unlike `fill_buf`, this will not attempt to fill the buffer if it is empty.
+    /// Unlike [`fill_buf`], this will not attempt to fill the buffer if it is empty.
+    ///
+    /// [`fill_buf`]: BufRead::fill_buf
     ///
     /// # Examples
     ///
@@ -338,27 +339,26 @@ where
 impl<R: Seek> Seek for BufReader<R> {
     /// Seek to an offset, in bytes, in the underlying reader.
     ///
-    /// The position used for seeking with `SeekFrom::Current(_)` is the
+    /// The position used for seeking with [`SeekFrom::Current`]`(_)` is the
     /// position the underlying reader would be at if the `BufReader<R>` had no
     /// internal buffer.
     ///
     /// Seeking always discards the internal buffer, even if the seek position
     /// would otherwise fall within it. This guarantees that calling
-    /// `.into_inner()` immediately after a seek yields the underlying reader
+    /// [`BufReader::into_inner()`] immediately after a seek yields the underlying reader
     /// at the same position.
     ///
     /// To seek without discarding the internal buffer, use [`BufReader::seek_relative`].
     ///
     /// See [`std::io::Seek`] for more details.
     ///
-    /// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`
+    /// Note: In the edge case where you're seeking with [`SeekFrom::Current`]`(n)`
     /// where `n` minus the internal buffer length overflows an `i64`, two
     /// seeks will be performed instead of one. If the second seek returns
-    /// `Err`, the underlying reader will be left at the same position it would
-    /// have if you called `seek` with `SeekFrom::Current(0)`.
+    /// [`Err`], the underlying reader will be left at the same position it would
+    /// have if you called `seek` with [`SeekFrom::Current`]`(0)`.
     ///
-    /// [`BufReader::seek_relative`]: struct.BufReader.html#method.seek_relative
-    /// [`std::io::Seek`]: trait.Seek.html
+    /// [`std::io::Seek`]: Seek
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
         let result: u64;
         if let SeekFrom::Current(n) = pos {
@@ -397,7 +397,7 @@ impl<R: Seek> Seek for BufReader<R> {
 /// *repeated* write calls to the same file or network socket. It does not
 /// help when writing very large amounts at once, or writing just one or a few
 /// times. It also provides no advantage when writing to a destination that is
-/// in memory, like a `Vec<u8>`.
+/// in memory, like a [`Vec`]<u8>`.
 ///
 /// It is critical to call [`flush`] before `BufWriter<W>` is dropped. Though
 /// dropping will attempt to flush the contents of the buffer, any errors
@@ -441,10 +441,9 @@ impl<R: Seek> Seek for BufReader<R> {
 /// together by the buffer and will all be written out in one system call when
 /// the `stream` is flushed.
 ///
-/// [`Write`]: ../../std/io/trait.Write.html
-/// [`TcpStream::write`]: ../../std/net/struct.TcpStream.html#method.write
-/// [`TcpStream`]: ../../std/net/struct.TcpStream.html
-/// [`flush`]: #method.flush
+/// [`TcpStream::write`]: Write::write
+/// [`TcpStream`]: crate::net::TcpStream
+/// [`flush`]: Write::flush
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct BufWriter<W: Write> {
     inner: Option<W>,
@@ -455,7 +454,7 @@ pub struct BufWriter<W: Write> {
     panicked: bool,
 }
 
-/// An error returned by `into_inner` which combines an error that
+/// An error returned by [`BufWriter::into_inner`] which combines an error that
 /// happened while writing out the buffer, and the buffered writer object
 /// which may be used to recover from the condition.
 ///
@@ -629,7 +628,7 @@ impl<W: Write> BufWriter<W> {
     ///
     /// # Errors
     ///
-    /// An `Err` will be returned if an error occurs while flushing the buffer.
+    /// An [`Err`] will be returned if an error occurs while flushing the buffer.
     ///
     /// # Examples
     ///
@@ -725,7 +724,8 @@ impl<W: Write> Drop for BufWriter<W> {
 }
 
 impl<W> IntoInnerError<W> {
-    /// Returns the error which caused the call to `into_inner()` to fail.
+    /// Returns the error which caused the call to [`BufWriter::into_inner()`]
+    /// to fail.
     ///
     /// This error was returned when attempting to write the internal buffer.
     ///
@@ -819,17 +819,15 @@ impl<W> fmt::Display for IntoInnerError<W> {
 /// Wraps a writer and buffers output to it, flushing whenever a newline
 /// (`0x0a`, `'\n'`) is detected.
 ///
-/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.
+/// The [`BufWriter`] struct wraps a writer and buffers its output.
 /// But it only does this batched write when it goes out of scope, or when the
 /// internal buffer is full. Sometimes, you'd prefer to write each line as it's
 /// completed, rather than the entire buffer at once. Enter `LineWriter`. It
 /// does exactly that.
 ///
-/// Like [`BufWriter`][bufwriter], a `LineWriter`’s buffer will also be flushed when the
+/// Like [`BufWriter`], a `LineWriter`’s buffer will also be flushed when the
 /// `LineWriter` goes out of scope or when its internal buffer is full.
 ///
-/// [bufwriter]: struct.BufWriter.html
-///
 /// If there's still a partial line in the buffer when the `LineWriter` is
 /// dropped, it will flush those contents.
 ///
@@ -979,7 +977,7 @@ impl<W: Write> LineWriter<W> {
     ///
     /// # Errors
     ///
-    /// An `Err` will be returned if an error occurs while flushing the buffer.
+    /// An [`Err`] will be returned if an error occurs while flushing the buffer.
     ///
     /// # Examples
     ///

library/std/src/io/cursor.rs

@@ -9,7 +9,7 @@ use core::convert::TryInto;
 /// [`Seek`] implementation.
 ///
 /// `Cursor`s are used with in-memory buffers, anything implementing
-/// `AsRef<[u8]>`, to allow them to implement [`Read`] and/or [`Write`],
+/// [`AsRef`]`<[u8]>`, to allow them to implement [`Read`] and/or [`Write`],
 /// allowing these buffers to be used anywhere you might use a reader or writer
 /// that does actual I/O.
 ///
@@ -23,12 +23,8 @@ use core::convert::TryInto;
 /// code, but use an in-memory buffer in our tests. We can do this with
 /// `Cursor`:
 ///
-/// [`Seek`]: trait.Seek.html
-/// [`Read`]: ../../std/io/trait.Read.html
-/// [`Write`]: ../../std/io/trait.Write.html
-/// [`Vec`]: ../../std/vec/struct.Vec.html
-/// [bytes]: ../../std/primitive.slice.html
-/// [`File`]: ../fs/struct.File.html
+/// [bytes]: crate::slice
+/// [`File`]: crate::fs::File
 ///
 /// ```no_run
 /// use std::io::prelude::*;
@@ -81,8 +77,8 @@ pub struct Cursor<T> {
 impl<T> Cursor<T> {
     /// Creates a new cursor wrapping the provided underlying in-memory buffer.
     ///
-    /// Cursor initial position is `0` even if underlying buffer (e.g., `Vec`)
-    /// is not empty. So writing to cursor starts with overwriting `Vec`
+    /// Cursor initial position is `0` even if underlying buffer (e.g., [`Vec`])
+    /// is not empty. So writing to cursor starts with overwriting [`Vec`]
     /// content, not with appending to it.
     ///
     /// # Examples

library/std/src/io/error.rs

@@ -4,8 +4,7 @@ use crate::fmt;
 use crate::result;
 use crate::sys;
 
-/// A specialized [`Result`](../result/enum.Result.html) type for I/O
-/// operations.
+/// A specialized [`Result`] type for I/O operations.
 ///
 /// This type is broadly used across [`std::io`] for any operation which may
 /// produce an error.
@@ -16,12 +15,13 @@ use crate::sys;
 /// While usual Rust style is to import types directly, aliases of [`Result`]
 /// often are not, to make it easier to distinguish between them. [`Result`] is
 /// generally assumed to be [`std::result::Result`][`Result`], and so users of this alias
-/// will generally use `io::Result` instead of shadowing the prelude's import
+/// will generally use `io::Result` instead of shadowing the [prelude]'s import
 /// of [`std::result::Result`][`Result`].
 ///
-/// [`std::io`]: ../io/index.html
-/// [`io::Error`]: ../io/struct.Error.html
-/// [`Result`]: ../result/enum.Result.html
+/// [`std::io`]: crate::io
+/// [`io::Error`]: Error
+/// [`Result`]: crate::result::Result
+/// [prelude]: crate::prelude
 ///
 /// # Examples
 ///
@@ -48,10 +48,9 @@ pub type Result<T> = result::Result<T, Error>;
 /// `Error` can be created with crafted error messages and a particular value of
 /// [`ErrorKind`].
 ///
-/// [`Read`]: ../io/trait.Read.html
-/// [`Write`]: ../io/trait.Write.html
-/// [`Seek`]: ../io/trait.Seek.html
-/// [`ErrorKind`]: enum.ErrorKind.html
+/// [`Read`]: crate::io::Read
+/// [`Write`]: crate::io::Write
+/// [`Seek`]: crate::io::Seek
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Error {
     repr: Repr,
@@ -83,7 +82,7 @@ struct Custom {
 ///
 /// It is used with the [`io::Error`] type.
 ///
-/// [`io::Error`]: struct.Error.html
+/// [`io::Error`]: Error
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow(deprecated)]
@@ -137,7 +136,7 @@ pub enum ErrorKind {
     /// For example, a function that reads a file into a string will error with
     /// `InvalidData` if the file's contents are not valid UTF-8.
     ///
-    /// [`InvalidInput`]: #variant.InvalidInput
+    /// [`InvalidInput`]: ErrorKind::InvalidInput
     #[stable(feature = "io_invalid_data", since = "1.2.0")]
     InvalidData,
     /// The I/O operation's timeout expired, causing it to be canceled.
@@ -150,8 +149,8 @@ pub enum ErrorKind {
     /// particular number of bytes but only a smaller number of bytes could be
     /// written.
     ///
-    /// [`write`]: ../../std/io/trait.Write.html#tymethod.write
-    /// [`Ok(0)`]: ../../std/io/type.Result.html
+    /// [`write`]: crate::io::Write::write
+    /// [`Ok(0)`]: Ok
     #[stable(feature = "rust1", since = "1.0.0")]
     WriteZero,
     /// This operation was interrupted.
@@ -220,9 +219,6 @@ impl From<ErrorKind> for Error {
     /// let error = Error::from(not_found);
     /// assert_eq!("entity not found", format!("{}", error));
     /// ```
-    ///
-    /// [`ErrorKind`]: ../../std/io/enum.ErrorKind.html
-    /// [`Error`]: ../../std/io/struct.Error.html
     #[inline]
     fn from(kind: ErrorKind) -> Error {
         Error { repr: Repr::Simple(kind) }
@@ -235,7 +231,7 @@ impl Error {
     ///
     /// This function is used to generically create I/O errors which do not
     /// originate from the OS itself. The `error` argument is an arbitrary
-    /// payload which will be contained in this `Error`.
+    /// payload which will be contained in this [`Error`].
     ///
     /// # Examples
     ///
@@ -264,7 +260,7 @@ impl Error {
     ///
     /// This function reads the value of `errno` for the target platform (e.g.
     /// `GetLastError` on Windows) and will return a corresponding instance of
-    /// `Error` for the error code.
+    /// [`Error`] for the error code.
     ///
     /// # Examples
     ///
@@ -278,7 +274,7 @@ impl Error {
         Error::from_raw_os_error(sys::os::errno() as i32)
     }
 
-    /// Creates a new instance of an `Error` from a particular OS error code.
+    /// Creates a new instance of an [`Error`] from a particular OS error code.
     ///
     /// # Examples
     ///
@@ -310,9 +306,12 @@ impl Error {
 
     /// Returns the OS error that this error represents (if any).
     ///
-    /// If this `Error` was constructed via `last_os_error` or
-    /// `from_raw_os_error`, then this function will return `Some`, otherwise
-    /// it will return `None`.
+    /// If this [`Error`] was constructed via [`last_os_error`] or
+    /// [`from_raw_os_error`], then this function will return [`Some`], otherwise
+    /// it will return [`None`].
+    ///
+    /// [`last_os_error`]: Error::last_os_error
+    /// [`from_raw_os_error`]: Error::from_raw_os_error
     ///
     /// # Examples
     ///
@@ -345,8 +344,10 @@ impl Error {
 
     /// Returns a reference to the inner error wrapped by this error (if any).
     ///
-    /// If this `Error` was constructed via `new` then this function will
-    /// return `Some`, otherwise it will return `None`.
+    /// If this [`Error`] was constructed via [`new`] then this function will
+    /// return [`Some`], otherwise it will return [`None`].
+    ///
+    /// [`new`]: Error::new
     ///
     /// # Examples
     ///
@@ -380,8 +381,10 @@ impl Error {
     /// Returns a mutable reference to the inner error wrapped by this error
     /// (if any).
     ///
-    /// If this `Error` was constructed via `new` then this function will
-    /// return `Some`, otherwise it will return `None`.
+    /// If this [`Error`] was constructed via [`new`] then this function will
+    /// return [`Some`], otherwise it will return [`None`].
+    ///
+    /// [`new`]: Error::new
     ///
     /// # Examples
     ///
@@ -448,8 +451,10 @@ impl Error {
 
     /// Consumes the `Error`, returning its inner error (if any).
     ///
-    /// If this `Error` was constructed via `new` then this function will
-    /// return `Some`, otherwise it will return `None`.
+    /// If this [`Error`] was constructed via [`new`] then this function will
+    /// return [`Some`], otherwise it will return [`None`].
+    ///
+    /// [`new`]: Error::new
     ///
     /// # Examples
     ///
@@ -480,7 +485,7 @@ impl Error {
         }
     }
 
-    /// Returns the corresponding `ErrorKind` for this error.
+    /// Returns the corresponding [`ErrorKind`] for this error.
     ///
     /// # Examples
     ///