Auto merge of #67440 - Mark-Simulacrum:rollup-z59a7ky, r=Mark-Simulacrum

Rollup of 6 pull requests

Successful merges:

 - #67253 (Add more delegations to the fmt docs and add doctests)
 - #67281 (add string.insert benchmarks)
 - #67351 (Set release channel on non-dist builders)
 - #67421 (Fix internal documentation typo)
 - #67432 (Fix toolstate history format)
 - #67436 (Correct the todo! stabilization version)

Failed merges:

r? @ghost

7 files changed, 129 insertions, 52 deletions

diff --git a/src/bootstrap/toolstate.rs b/src/bootstrap/toolstate.rs
index a6d9ef38e57..f0e343ef22a 100644
--- a/src/bootstrap/toolstate.rs
+++ b/src/bootstrap/toolstate.rs
@@ -13,13 +13,13 @@ use std::env;
 // Each cycle is 42 days long (6 weeks); the last week is 35..=42 then.
 const BETA_WEEK_START: u64 = 35;
 
-#[cfg(linux)]
+#[cfg(target_os = "linux")]
 const OS: Option<&str> = Some("linux");
 
 #[cfg(windows)]
 const OS: Option<&str> = Some("windows");
 
-#[cfg(all(not(linux), not(windows)))]
+#[cfg(all(not(target_os = "linux"), not(windows)))]
 const OS: Option<&str> = None;
 
 type ToolstateData = HashMap<Box<str>, ToolState>;
@@ -379,7 +379,7 @@ fn change_toolstate(
     let mut regressed = false;
     for repo_state in old_toolstate {
         let tool = &repo_state.tool;
-        let state = if cfg!(linux) {
+        let state = if cfg!(target_os = "linux") {
             &repo_state.linux
         } else if cfg!(windows) {
             &repo_state.windows
@@ -413,7 +413,7 @@ fn change_toolstate(
     let history_path = format!("rust-toolstate/history/{}.tsv", OS.expect("linux/windows only"));
     let mut file = t!(fs::read_to_string(&history_path));
     let end_of_first_line = file.find('\n').unwrap();
-    file.insert_str(end_of_first_line, &format!("{}\t{}\n", commit, toolstate_serialized));
+    file.insert_str(end_of_first_line, &format!("\n{}\t{}", commit, toolstate_serialized));
     t!(fs::write(&history_path, file));
 }
 
diff --git a/src/ci/run.sh b/src/ci/run.sh
index 38d1d2baf25..73c3a964f53 100755
--- a/src/ci/run.sh
+++ b/src/ci/run.sh
@@ -44,8 +44,13 @@ fi
 # FIXME: need a scheme for changing this `nightly` value to `beta` and `stable`
 #        either automatically or manually.
 export RUST_RELEASE_CHANNEL=nightly
+
+# Always set the release channel for bootstrap; this is normally not important (i.e., only dist
+# builds would seem to matter) but in practice bootstrap wants to know whether we're targeting
+# master, beta, or stable with a build to determine whether to run some checks (notably toolstate).
+RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --release-channel=$RUST_RELEASE_CHANNEL"
+
 if [ "$DEPLOY$DEPLOY_ALT" = "1" ]; then
-  RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --release-channel=$RUST_RELEASE_CHANNEL"
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --enable-llvm-static-stdcpp"
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --set rust.remap-debuginfo"
   RUST_CONFIGURE_ARGS="$RUST_CONFIGURE_ARGS --debuginfo-level-std=1"
diff --git a/src/liballoc/benches/string.rs b/src/liballoc/benches/string.rs
index 2933014cb58..599c8b16828 100644
--- a/src/liballoc/benches/string.rs
+++ b/src/liballoc/benches/string.rs
@@ -122,3 +122,43 @@ fn bench_to_string(b: &mut Bencher) {
              Lorem ipsum dolor sit amet, consectetur. ";
     b.iter(|| s.to_string())
 }
+
+#[bench]
+fn bench_insert_char_short(b: &mut Bencher) {
+    let s = "Hello, World!";
+    b.iter(|| {
+        let mut x = String::from(s);
+        black_box(&mut x).insert(6, black_box(' '));
+        x
+    })
+}
+
+#[bench]
+fn bench_insert_char_long(b: &mut Bencher) {
+    let s = "Hello, World!";
+    b.iter(|| {
+        let mut x = String::from(s);
+        black_box(&mut x).insert(6, black_box('❤'));
+        x
+    })
+}
+
+#[bench]
+fn bench_insert_str_short(b: &mut Bencher) {
+    let s = "Hello, World!";
+    b.iter(|| {
+        let mut x = String::from(s);
+        black_box(&mut x).insert_str(6, black_box(" "));
+        x
+    })
+}
+
+#[bench]
+fn bench_insert_str_long(b: &mut Bencher) {
+    let s = "Hello, World!";
+    b.iter(|| {
+        let mut x = String::from(s);
+        black_box(&mut x).insert_str(6, black_box(" rustic "));
+        x
+    })
+}
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 223f91d909b..793c1f124ed 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -63,7 +63,7 @@ pub mod rt {
 ///
 /// let pythagorean_triple = Triangle { a: 3.0, b: 4.0, c: 5.0 };
 ///
-/// println!("{}", pythagorean_triple);
+/// assert_eq!(format!("{}", pythagorean_triple), "(3, 4, 5)");
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub type Result = result::Result<(), Error>;
@@ -440,7 +440,7 @@ impl Display for Arguments<'_> {
 ///
 /// let origin = Point { x: 0, y: 0 };
 ///
-/// println!("The origin is: {:?}", origin);
+/// assert_eq!(format!("The origin is: {:?}", origin), "The origin is: Point { x: 0, y: 0 }");
 /// ```
 ///
 /// Manually implementing:
@@ -455,28 +455,25 @@ impl Display for Arguments<'_> {
 ///
 /// impl fmt::Debug for Point {
 ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-///         write!(f, "Point {{ x: {}, y: {} }}", self.x, self.y)
+///         f.debug_struct("Point")
+///          .field("x", &self.x)
+///          .field("y", &self.y)
+///          .finish()
 ///     }
 /// }
 ///
 /// let origin = Point { x: 0, y: 0 };
 ///
-/// println!("The origin is: {:?}", origin);
+/// assert_eq!(format!("The origin is: {:?}", origin), "The origin is: Point { x: 0, y: 0 }");
 /// ```
 ///
-/// This outputs:
-///
-/// ```text
-/// The origin is: Point { x: 0, y: 0 }
-/// ```
-///
-/// There are a number of `debug_*` methods on [`Formatter`] to help you with manual
-/// implementations, such as [`debug_struct`][debug_struct].
+/// There are a number of helper methods on the [`Formatter`] struct to help you with manual
+/// implementations, such as [`debug_struct`].
 ///
 /// `Debug` implementations using either `derive` or the debug builder API
 /// on [`Formatter`] support pretty-printing using the alternate flag: `{:#?}`.
 ///
-/// [debug_struct]: ../../std/fmt/struct.Formatter.html#method.debug_struct
+/// [`debug_struct`]: ../../std/fmt/struct.Formatter.html#method.debug_struct
 /// [`Formatter`]: ../../std/fmt/struct.Formatter.html
 ///
 /// Pretty-printing with `#?`:
@@ -490,17 +487,13 @@ impl Display for Arguments<'_> {
 ///
 /// let origin = Point { x: 0, y: 0 };
 ///
-/// println!("The origin is: {:#?}", origin);
-/// ```
-///
-/// This outputs:
-///
-/// ```text
-/// The origin is: Point {
+/// assert_eq!(format!("The origin is: {:#?}", origin),
+/// "The origin is: Point {
 ///     x: 0,
-///     y: 0
-/// }
+///     y: 0,
+/// }");
 /// ```
+
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(
     on(
@@ -528,12 +521,20 @@ pub trait Debug {
     ///
     /// impl fmt::Debug for Position {
     ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-    ///         write!(f, "({:?}, {:?})", self.longitude, self.latitude)
+    ///         f.debug_tuple("")
+    ///          .field(&self.longitude)
+    ///          .field(&self.latitude)
+    ///          .finish()
     ///     }
     /// }
     ///
-    /// assert_eq!("(1.987, 2.983)".to_owned(),
-    ///            format!("{:?}", Position { longitude: 1.987, latitude: 2.983, }));
+    /// let position = Position { longitude: 1.987, latitude: 2.983 };
+    /// assert_eq!(format!("{:?}", position), "(1.987, 2.983)");
+    ///
+    /// assert_eq!(format!("{:#?}", position), "(
+    ///     1.987,
+    ///     2.983,
+    /// )");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     fn fmt(&self, f: &mut Formatter<'_>) -> Result;
@@ -584,7 +585,7 @@ pub use macros::Debug;
 ///
 /// let origin = Point { x: 0, y: 0 };
 ///
-/// println!("The origin is: {}", origin);
+/// assert_eq!(format!("The origin is: {}", origin), "The origin is: (0, 0)");
 /// ```
 #[rustc_on_unimplemented(
     on(
@@ -618,7 +619,7 @@ pub trait Display {
     ///     }
     /// }
     ///
-    /// assert_eq!("(1.987, 2.983)".to_owned(),
+    /// assert_eq!("(1.987, 2.983)",
     ///            format!("{}", Position { longitude: 1.987, latitude: 2.983, }));
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -668,7 +669,9 @@ pub trait Display {
 ///
 /// let l = Length(9);
 ///
-/// println!("l as octal is: {:o}", l);
+/// assert_eq!(format!("l as octal is: {:o}", l), "l as octal is: 11");
+///
+/// assert_eq!(format!("l as octal is: {:#06o}", l), "l as octal is: 0o0011");
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Octal {
@@ -718,7 +721,12 @@ pub trait Octal {
 ///
 /// let l = Length(107);
 ///
-/// println!("l as binary is: {:b}", l);
+/// assert_eq!(format!("l as binary is: {:b}", l), "l as binary is: 1101011");
+///
+/// assert_eq!(
+///     format!("l as binary is: {:#032b}", l),
+///     "l as binary is: 0b000000000000000000000001101011"
+/// );
 /// ```
 ///
 /// [module]: ../../std/fmt/index.html
@@ -777,7 +785,9 @@ pub trait Binary {
 ///
 /// let l = Length(9);
 ///
-/// println!("l as hex is: {:x}", l);
+/// assert_eq!(format!("l as hex is: {:x}", l), "l as hex is: 9");
+///
+/// assert_eq!(format!("l as hex is: {:#010x}", l), "l as hex is: 0x00000009");
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait LowerHex {
@@ -828,9 +838,11 @@ pub trait LowerHex {
 ///     }
 /// }
 ///
-/// let l = Length(9);
+/// let l = Length(i32::max_value());
 ///
-/// println!("l as hex is: {:X}", l);
+/// assert_eq!(format!("l as hex is: {:X}", l), "l as hex is: 7FFFFFFF");
+///
+/// assert_eq!(format!("l as hex is: {:#010X}", l), "l as hex is: 0x7FFFFFFF");
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait UpperHex {
@@ -877,6 +889,10 @@ pub trait UpperHex {
 /// let l = Length(42);
 ///
 /// println!("l is in memory here: {:p}", l);
+///
+/// let l_ptr = format!("{:018p}", l);
+/// assert_eq!(l_ptr.len(), 18);
+/// assert_eq!(&l_ptr[..2], "0x");
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Pointer {
@@ -912,14 +928,22 @@ pub trait Pointer {
 ///
 /// impl fmt::LowerExp for Length {
 ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-///         let val = self.0;
-///         write!(f, "{}e1", val / 10)
+///         let val = f64::from(self.0);
+///         fmt::LowerExp::fmt(&val, f) // delegate to f64's implementation
 ///     }
 /// }
 ///
 /// let l = Length(100);
 ///
-/// println!("l in scientific notation is: {:e}", l);
+/// assert_eq!(
+///     format!("l in scientific notation is: {:e}", l),
+///     "l in scientific notation is: 1e2"
+/// );
+///
+/// assert_eq!(
+///     format!("l in scientific notation is: {:05e}", l),
+///     "l in scientific notation is: 001e2"
+/// );
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait LowerExp {
@@ -955,14 +979,22 @@ pub trait LowerExp {
 ///
 /// impl fmt::UpperExp for Length {
 ///     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-///         let val = self.0;
-///         write!(f, "{}E1", val / 10)
+///         let val = f64::from(self.0);
+///         fmt::UpperExp::fmt(&val, f) // delegate to f64's implementation
 ///     }
 /// }
 ///
 /// let l = Length(100);
 ///
-/// println!("l in scientific notation is: {:E}", l);
+/// assert_eq!(
+///     format!("l in scientific notation is: {:E}", l),
+///     "l in scientific notation is: 1E2"
+/// );
+///
+/// assert_eq!(
+///     format!("l in scientific notation is: {:05E}", l),
+///     "l in scientific notation is: 001E2"
+/// );
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait UpperExp {
@@ -1807,8 +1839,7 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// // prints "[10, 11]"
-    /// println!("{:?}", Foo(vec![10, 11]));
+    /// assert_eq!(format!("{:?}", Foo(vec![10, 11])), "[10, 11]");
     /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn debug_list<'b>(&'b mut self) -> DebugList<'b, 'a> {
@@ -1831,8 +1862,7 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// // prints "{10, 11}"
-    /// println!("{:?}", Foo(vec![10, 11]));
+    /// assert_eq!(format!("{:?}", Foo(vec![10, 11])), "{10, 11}");
     /// ```
     ///
     /// [`format_args!`]: ../../std/macro.format_args.html
@@ -1890,8 +1920,10 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// // prints "{"A": 10, "B": 11}"
-    /// println!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)]));
+    /// assert_eq!(
+    ///     format!("{:?}",  Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
+    ///     r#"{"A": 10, "B": 11}"#
+    ///  );
     /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn debug_map<'b>(&'b mut self) -> DebugMap<'b, 'a> {
diff --git a/src/libcore/macros/mod.rs b/src/libcore/macros/mod.rs
index cf460745ffa..dd06da7a6d2 100644
--- a/src/libcore/macros/mod.rs
+++ b/src/libcore/macros/mod.rs
@@ -686,7 +686,7 @@ macro_rules! unimplemented {
 /// }
 /// ```
 #[macro_export]
-#[stable(feature = "todo_macro", since = "1.39.0")]
+#[stable(feature = "todo_macro", since = "1.40.0")]
 macro_rules! todo {
     () => (panic!("not yet implemented"));
     ($($arg:tt)+) => (panic!("not yet implemented: {}", $crate::format_args!($($arg)+)));
diff --git a/src/librustc_interface/interface.rs b/src/librustc_interface/interface.rs
index beb2465bd4a..2365fc3ee2e 100644
--- a/src/librustc_interface/interface.rs
+++ b/src/librustc_interface/interface.rs
@@ -25,7 +25,7 @@ use syntax_pos::edition;
 pub type Result<T> = result::Result<T, ErrorReported>;
 
 /// Represents a compiler session.
-/// Can be used run `rustc_interface` queries.
+/// Can be used to run `rustc_interface` queries.
 /// Created by passing `Config` to `run_compiler`.
 pub struct Compiler {
     pub(crate) sess: Lrc<Session>,
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 340313b06dd..9930b8f63af 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -524,8 +524,8 @@ pub use core::{
     unreachable,
     write,
     writeln,
-    // Unstable
     todo,
+    // Unstable
     matches,
 };