Auto merge of #92068 - fee1-dead:libcore2021, r=m-ou-se

Switch all libraries to the 2021 edition

The fix for https://github.com/rust-lang/rust/issues/88638#issuecomment-996620107 is to simply add const-stability for these functions.

r? `@m-ou-se`

Closes #88638.

library/alloc/Cargo.toml

@@ -6,7 +6,7 @@ repository = "https://github.com/rust-lang/rust.git"
 description = "The Rust core allocation and collections library"
 autotests = false
 autobenches = false
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 core = { path = "../core" }

library/alloc/src/vec/mod.rs

@@ -3004,14 +3004,12 @@ impl<T, A: Allocator, const N: usize> TryFrom<Vec<T, A>> for [T; N] {
     /// # Examples
     ///
     /// ```
-    /// use std::convert::TryInto;
     /// assert_eq!(vec![1, 2, 3].try_into(), Ok([1, 2, 3]));
     /// assert_eq!(<Vec<i32>>::new().try_into(), Ok([]));
     /// ```
     ///
     /// If the length doesn't match, the input comes back in `Err`:
     /// ```
-    /// use std::convert::TryInto;
     /// let r: Result<[i32; 4], _> = (0..10).collect::<Vec<_>>().try_into();
     /// assert_eq!(r, Err(vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]));
     /// ```
@@ -3019,7 +3017,6 @@ impl<T, A: Allocator, const N: usize> TryFrom<Vec<T, A>> for [T; N] {
     /// If you're fine with just getting a prefix of the `Vec<T>`,
     /// you can call [`.truncate(N)`](Vec::truncate) first.
     /// ```
-    /// use std::convert::TryInto;
     /// let mut v = String::from("hello world").into_bytes();
     /// v.sort();
     /// v.truncate(2);

library/core/Cargo.toml

@@ -6,7 +6,7 @@ repository = "https://github.com/rust-lang/rust.git"
 description = "The Rust Core Library"
 autotests = false
 autobenches = false
-edition = "2018"
+edition = "2021"
 
 [lib]
 test = false

library/core/src/array/mod.rs

@@ -66,8 +66,6 @@ where
 ///
 /// ```rust
 /// #![feature(array_from_fn)]
-/// # // Apparently these doc tests are still on edition2018
-/// # use std::convert::TryInto;
 ///
 /// let array: Result<[u8; 5], _> = std::array::try_from_fn(|i| i.try_into());
 /// assert_eq!(array, Ok([0, 1, 2, 3, 4]));

library/core/src/convert/mod.rs

@@ -426,8 +426,6 @@ pub trait TryInto<T>: Sized {
 /// `TryFrom<T>` can be implemented as follows:
 ///
 /// ```
-/// use std::convert::TryFrom;
-///
 /// struct GreaterThanZero(i32);
 ///
 /// impl TryFrom<i32> for GreaterThanZero {
@@ -448,8 +446,6 @@ pub trait TryInto<T>: Sized {
 /// As described, [`i32`] implements `TryFrom<`[`i64`]`>`:
 ///
 /// ```
-/// use std::convert::TryFrom;
-///
 /// let big_number = 1_000_000_000_000i64;
 /// // Silently truncates `big_number`, requires detecting
 /// // and handling the truncation after the fact.

library/core/src/iter/traits/collect.rs

@@ -15,8 +15,6 @@
 /// Basic usage:
 ///
 /// ```
-/// use std::iter::FromIterator;
-///
 /// let five_fives = std::iter::repeat(5).take(5);
 ///
 /// let v = Vec::from_iter(five_fives);
@@ -37,8 +35,6 @@
 /// Implementing `FromIterator` for your type:
 ///
 /// ```
-/// use std::iter::FromIterator;
-///
 /// // A sample collection, that's just a wrapper over Vec<T>
 /// #[derive(Debug)]
 /// struct MyCollection(Vec<i32>);
@@ -102,8 +98,6 @@ pub trait FromIterator<A>: Sized {
     /// Basic usage:
     ///
     /// ```
-    /// use std::iter::FromIterator;
-    ///
     /// let five_fives = std::iter::repeat(5).take(5);
     ///
     /// let v = Vec::from_iter(five_fives);

library/core/src/iter/traits/iterator.rs

@@ -1155,8 +1155,6 @@ pub trait Iterator {
     /// Stopping after an initial [`None`]:
     ///
     /// ```
-    /// use std::convert::TryFrom;
-    ///
     /// let a = [0, 1, 2, -3, 4, 5, -6];
     ///
     /// let iter = a.iter().map_while(|x| u32::try_from(*x).ok());
@@ -1172,8 +1170,6 @@ pub trait Iterator {
     /// removed:
     ///
     /// ```
-    /// use std::convert::TryFrom;
-    ///
     /// let a = [1, 2, -3, 4];
     /// let mut iter = a.iter();
     ///

library/core/src/num/int_macros.rs

@@ -2602,8 +2602,6 @@ macro_rules! int_impl {
         /// When starting from a slice rather than an array, fallible conversion APIs can be used:
         ///
         /// ```
-        /// use std::convert::TryInto;
-        ///
         #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
         #[doc = concat!("    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
         ///     *input = rest;
@@ -2633,8 +2631,6 @@ macro_rules! int_impl {
         /// When starting from a slice rather than an array, fallible conversion APIs can be used:
         ///
         /// ```
-        /// use std::convert::TryInto;
-        ///
         #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
         #[doc = concat!("    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
         ///     *input = rest;
@@ -2675,8 +2671,6 @@ macro_rules! int_impl {
         /// When starting from a slice rather than an array, fallible conversion APIs can be used:
         ///
         /// ```
-        /// use std::convert::TryInto;
-        ///
         #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
         #[doc = concat!("    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
         ///     *input = rest;

library/core/src/num/uint_macros.rs

@@ -2323,8 +2323,6 @@ macro_rules! uint_impl {
         /// When starting from a slice rather than an array, fallible conversion APIs can be used:
         ///
         /// ```
-        /// use std::convert::TryInto;
-        ///
         #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
         #[doc = concat!("    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
         ///     *input = rest;
@@ -2354,8 +2352,6 @@ macro_rules! uint_impl {
         /// When starting from a slice rather than an array, fallible conversion APIs can be used:
         ///
         /// ```
-        /// use std::convert::TryInto;
-        ///
         #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
         #[doc = concat!("    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
         ///     *input = rest;
@@ -2396,8 +2392,6 @@ macro_rules! uint_impl {
         /// When starting from a slice rather than an array, fallible conversion APIs can be used:
         ///
         /// ```
-        /// use std::convert::TryInto;
-        ///
         #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
         #[doc = concat!("    let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
         ///     *input = rest;

library/core/src/panicking.rs

@@ -51,6 +51,7 @@ pub const fn panic(expr: &'static str) -> ! {
 #[inline]
 #[track_caller]
 #[lang = "panic_str"] // needed for `non-fmt-panics` lint
+#[rustc_const_unstable(feature = "core_panic", issue = "none")]
 pub const fn panic_str(expr: &str) -> ! {
     panic_display(&expr);
 }
@@ -59,6 +60,7 @@ pub const fn panic_str(expr: &str) -> ! {
 #[track_caller]
 #[lang = "panic_display"] // needed for const-evaluated panics
 #[rustc_do_not_const_check] // hooked by const-eval
+#[rustc_const_unstable(feature = "core_panic", issue = "none")]
 pub const fn panic_display<T: fmt::Display>(x: &T) -> ! {
     panic_fmt(format_args!("{}", *x));
 }
@@ -89,6 +91,7 @@ fn panic_bounds_check(index: usize, len: usize) -> ! {
 #[track_caller]
 #[lang = "panic_fmt"] // needed for const-evaluated panics
 #[rustc_do_not_const_check] // hooked by const-eval
+#[rustc_const_unstable(feature = "core_panic", issue = "none")]
 pub const fn panic_fmt(fmt: fmt::Arguments<'_>) -> ! {
     if cfg!(feature = "panic_immediate_abort") {
         super::intrinsics::abort()
@@ -109,6 +112,7 @@ pub const fn panic_fmt(fmt: fmt::Arguments<'_>) -> ! {
 
 /// This function is used instead of panic_fmt in const eval.
 #[lang = "const_panic_fmt"]
+#[rustc_const_unstable(feature = "core_panic", issue = "none")]
 pub const fn const_panic_fmt(fmt: fmt::Arguments<'_>) -> ! {
     if let Some(msg) = fmt.as_str() {
         panic_str(msg);

library/panic_abort/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.0"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/rust.git"
 description = "Implementation of Rust panics via process aborts"
-edition = "2018"
+edition = "2021"
 
 [lib]
 test = false

library/panic_unwind/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.0.0"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/rust.git"
 description = "Implementation of Rust panics via stack unwinding"
-edition = "2018"
+edition = "2021"
 
 [lib]
 test = false

library/proc_macro/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "proc_macro"
 version = "0.0.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 std = { path = "../std" }

library/profiler_builtins/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "profiler_builtins"
 version = "0.0.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 test = false

library/rustc-std-workspace-alloc/Cargo.toml

@@ -5,7 +5,7 @@ license = 'MIT OR Apache-2.0'
 description = """
 Hack for the compiler's own build system
 """
-edition = "2018"
+edition = "2021"
 
 [lib]
 path = "lib.rs"

library/rustc-std-workspace-core/Cargo.toml

@@ -5,7 +5,7 @@ license = 'MIT OR Apache-2.0'
 description = """
 Hack for the compiler's own build system
 """
-edition = "2018"
+edition = "2021"
 
 [lib]
 path = "lib.rs"

library/rustc-std-workspace-std/Cargo.toml

@@ -5,7 +5,7 @@ license = 'MIT OR Apache-2.0'
 description = """
 Hack for the compiler's own build system
 """
-edition = "2018"
+edition = "2021"
 
 [lib]
 path = "lib.rs"

library/test/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "test"
 version = "0.0.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 crate-type = ["dylib", "rlib"]

library/unwind/Cargo.toml

@@ -3,7 +3,7 @@ name = "unwind"
 version = "0.0.0"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/rust.git"
-edition = "2018"
+edition = "2021"
 include = [
   '/libunwind/*',
 ]

src/tools/tidy/src/edition.rs

@@ -2,11 +2,6 @@
 
 use std::path::Path;
 
-fn is_edition_2018(mut line: &str) -> bool {
-    line = line.trim();
-    line == "edition = \"2018\""
-}
-
 fn is_edition_2021(mut line: &str) -> bool {
     line = line.trim();
     line == "edition = \"2021\""
@@ -23,27 +18,13 @@ pub fn check(path: &Path, bad: &mut bool) {
                 return;
             }
 
-            // Not all library crates are ready to migrate to 2021.
-            if file.components().any(|c| c.as_os_str() == "library")
-                && file.components().all(|c| c.as_os_str() != "std")
-            {
-                let has = contents.lines().any(is_edition_2018);
-                if !has {
-                    tidy_error!(
-                        bad,
-                        "{} doesn't have `edition = \"2018\"` on a separate line",
-                        file.display()
-                    );
-                }
-            } else {
-                let is_2021 = contents.lines().any(is_edition_2021);
-                if !is_2021 {
-                    tidy_error!(
-                        bad,
-                        "{} doesn't have `edition = \"2021\"` on a separate line",
-                        file.display()
-                    );
-                }
+            let is_2021 = contents.lines().any(is_edition_2021);
+            if !is_2021 {
+                tidy_error!(
+                    bad,
+                    "{} doesn't have `edition = \"2021\"` on a separate line",
+                    file.display()
+                );
             }
         },
     );