Auto merge of #55347 - pietroalbini:rollup, r=pietroalbini

Rollup of 22 pull requests

Successful merges:

 - #53507 (Add doc for impl From for Waker)
 - #53931 (Gradually expanding libstd's keyword documentation)
 - #54965 (update tcp stream documentation)
 - #54977 (Accept `Option<Box<$t:ty>>` in macro argument)
 - #55138 (in which unused-parens suggestions heed what the user actually wrote)
 - #55173 (Suggest appropriate syntax on missing lifetime specifier in return type)
 - #55200 (Documents `From` implementations for `Stdio`)
 - #55245 (submodules: update clippy from 5afdf8b7 to b1d03437)
 - #55247 (Clarified code example in char primitive doc)
 - #55251 (Fix a typo in the documentation of RangeInclusive)
 - #55253 (only issue "variant of the expected type" suggestion for enums)
 - #55254 (Correct trailing ellipsis in name_from_pat)
 - #55269 (fix typos in various places)
 - #55282 (Remove redundant clone)
 - #55285 (Do some copy editing on the release notes)
 - #55291 (Update stdsimd submodule)
 - #55296 (Set RUST_BACKTRACE=0 for rustdoc-ui/failed-doctest-output.rs)
 - #55306 (Regression test for #54478.)
 - #55328 (Fix doc for new copysign functions)
 - #55340 (Operands no longer appear in places)
 - #55345 (Remove is_null)
 - #55348 (Update RELEASES.md after destabilization of non_modrs_mods)

Failed merges:

r? @ghost

1 files changed, 88 insertions, 0 deletions

diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index 58ac4e94408..a9219f75362 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -1016,6 +1016,28 @@ impl fmt::Debug for Stdio {
 
 #[stable(feature = "stdio_from", since = "1.20.0")]
 impl From<ChildStdin> for Stdio {
+    /// Converts a `ChildStdin` into a `Stdio`
+    ///
+    /// # Examples
+    ///
+    /// `ChildStdin` will be converted to `Stdio` using `Stdio::from` under the hood.
+    ///
+    /// ```rust
+    /// use std::process::{Command, Stdio};
+    ///
+    /// let reverse = Command::new("rev")
+    ///     .stdin(Stdio::piped())
+    ///     .spawn()
+    ///     .expect("failed reverse command");
+    ///
+    /// let _echo = Command::new("echo")
+    ///     .arg("Hello, world!")
+    ///     .stdout(reverse.stdin.unwrap()) // Converted into a Stdio here
+    ///     .output()
+    ///     .expect("failed echo command");
+    ///
+    /// // "!dlrow ,olleH" echoed to console
+    /// ```
     fn from(child: ChildStdin) -> Stdio {
         Stdio::from_inner(child.into_inner().into())
     }
@@ -1023,6 +1045,28 @@ impl From<ChildStdin> for Stdio {
 
 #[stable(feature = "stdio_from", since = "1.20.0")]
 impl From<ChildStdout> for Stdio {
+    /// Converts a `ChildStdout` into a `Stdio`
+    ///
+    /// # Examples
+    ///
+    /// `ChildStdout` will be converted to `Stdio` using `Stdio::from` under the hood.
+    ///
+    /// ```rust
+    /// use std::process::{Command, Stdio};
+    ///
+    /// let hello = Command::new("echo")
+    ///     .arg("Hello, world!")
+    ///     .stdout(Stdio::piped())
+    ///     .spawn()
+    ///     .expect("failed echo command");
+    ///
+    /// let reverse = Command::new("rev")
+    ///     .stdin(hello.stdout.unwrap())  // Converted into a Stdio here
+    ///     .output()
+    ///     .expect("failed reverse command");
+    ///
+    /// assert_eq!(reverse.stdout, b"!dlrow ,olleH\n");
+    /// ```
     fn from(child: ChildStdout) -> Stdio {
         Stdio::from_inner(child.into_inner().into())
     }
@@ -1030,6 +1074,30 @@ impl From<ChildStdout> for Stdio {
 
 #[stable(feature = "stdio_from", since = "1.20.0")]
 impl From<ChildStderr> for Stdio {
+    /// Converts a `ChildStderr` into a `Stdio`
+    ///
+    /// # Examples
+    ///
+    /// ```rust,no_run
+    /// use std::process::{Command, Stdio};
+    ///
+    /// let reverse = Command::new("rev")
+    ///     .arg("non_existing_file.txt")
+    ///     .stderr(Stdio::piped())
+    ///     .spawn()
+    ///     .expect("failed reverse command");
+    ///
+    /// let cat = Command::new("cat")
+    ///     .arg("-")
+    ///     .stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
+    ///     .output()
+    ///     .expect("failed echo command");
+    ///
+    /// assert_eq!(
+    ///     String::from_utf8_lossy(&cat.stdout),
+    ///     "rev: cannot open non_existing_file.txt: No such file or directory\n"
+    /// );
+    /// ```
     fn from(child: ChildStderr) -> Stdio {
         Stdio::from_inner(child.into_inner().into())
     }
@@ -1037,6 +1105,26 @@ impl From<ChildStderr> for Stdio {
 
 #[stable(feature = "stdio_from", since = "1.20.0")]
 impl From<fs::File> for Stdio {
+    /// Converts a `File` into a `Stdio`
+    ///
+    /// # Examples
+    ///
+    /// `File` will be converted to `Stdio` using `Stdio::from` under the hood.
+    ///
+    /// ```rust,no_run
+    /// use std::fs::File;
+    /// use std::process::Command;
+    ///
+    /// // With the `foo.txt` file containing `Hello, world!"
+    /// let file = File::open("foo.txt").unwrap();
+    ///
+    /// let reverse = Command::new("rev")
+    ///     .stdin(file)  // Implicit File convertion into a Stdio
+    ///     .output()
+    ///     .expect("failed reverse command");
+    ///
+    /// assert_eq!(reverse.stdout, b"!dlrow ,olleH");
+    /// ```
     fn from(file: fs::File) -> Stdio {
         Stdio::from_inner(file.into_inner().into())
     }