Auto merge of rust-lang#137571 - tgross35:rollup-i1tcnv1, r=tgross35

Rollup of 8 pull requests

Successful merges:

 - rust-lang#134655 (Stabilize `hash_extract_if`)
 - rust-lang#135933 (Explain how Vec::with_capacity is faithful)
 - rust-lang#136668 (Stabilize `core::str::from_utf8_mut` as `const`)
 - rust-lang#136775 (Update `String::from_raw_parts` safety requirements)
 - rust-lang#137109 (stabilize extract_if)
 - rust-lang#137349 (Implement `read_buf` for zkVM stdin)
 - rust-lang#137493 (configure.py: don't instruct user to run nonexistent program)
 - rust-lang#137516 (remove some unnecessary rustc_const_unstable)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

alloc/src/collections/linked_list.rs

@@ -1140,7 +1140,6 @@ impl<T, A: Allocator> LinkedList<T, A> {
     /// Splitting a list into evens and odds, reusing the original list:
     ///
     /// ```
-    /// #![feature(extract_if)]
     /// use std::collections::LinkedList;
     ///
     /// let mut numbers: LinkedList<u32> = LinkedList::new();
@@ -1152,7 +1151,7 @@ impl<T, A: Allocator> LinkedList<T, A> {
     /// assert_eq!(evens.into_iter().collect::<Vec<_>>(), vec![2, 4, 6, 8, 14]);
     /// assert_eq!(odds.into_iter().collect::<Vec<_>>(), vec![1, 3, 5, 9, 11, 13, 15]);
     /// ```
-    #[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+    #[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
     pub fn extract_if<F>(&mut self, filter: F) -> ExtractIf<'_, T, F, A>
     where
         F: FnMut(&mut T) -> bool,
@@ -1932,7 +1931,7 @@ impl<'a, T, A: Allocator> CursorMut<'a, T, A> {
 }
 
 /// An iterator produced by calling `extract_if` on LinkedList.
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
 #[must_use = "iterators are lazy and do nothing unless consumed"]
 pub struct ExtractIf<
     'a,
@@ -1947,7 +1946,7 @@ pub struct ExtractIf<
     old_len: usize,
 }
 
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<T, F, A: Allocator> Iterator for ExtractIf<'_, T, F, A>
 where
     F: FnMut(&mut T) -> bool,
@@ -1976,7 +1975,7 @@ where
     }
 }
 
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<T: fmt::Debug, F> fmt::Debug for ExtractIf<'_, T, F> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("ExtractIf").field(&self.list).finish()

alloc/src/string.rs

@@ -966,11 +966,8 @@ impl String {
     /// This is highly unsafe, due to the number of invariants that aren't
     /// checked:
     ///
-    /// * The memory at `buf` needs to have been previously allocated by the
-    ///   same allocator the standard library uses, with a required alignment of exactly 1.
-    /// * `length` needs to be less than or equal to `capacity`.
-    /// * `capacity` needs to be the correct value.
-    /// * The first `length` bytes at `buf` need to be valid UTF-8.
+    /// * all safety requirements for [`Vec::<u8>::from_raw_parts`].
+    /// * all safety requirements for [`String::from_utf8_unchecked`].
     ///
     /// Violating these may cause problems like corrupting the allocator's
     /// internal data structures. For example, it is normally **not** safe to

alloc/src/vec/extract_if.rs

@@ -12,12 +12,10 @@ use crate::alloc::{Allocator, Global};
 /// # Example
 ///
 /// ```
-/// #![feature(extract_if)]
-///
 /// let mut v = vec![0, 1, 2];
 /// let iter: std::vec::ExtractIf<'_, _, _> = v.extract_if(.., |x| *x % 2 == 0);
 /// ```
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
 #[derive(Debug)]
 #[must_use = "iterators are lazy and do nothing unless consumed"]
 pub struct ExtractIf<
@@ -59,7 +57,7 @@ impl<'a, T, F, A: Allocator> ExtractIf<'a, T, F, A> {
     }
 }
 
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<T, F, A: Allocator> Iterator for ExtractIf<'_, T, F, A>
 where
     F: FnMut(&mut T) -> bool,
@@ -95,7 +93,7 @@ where
     }
 }
 
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<T, F, A: Allocator> Drop for ExtractIf<'_, T, F, A> {
     fn drop(&mut self) {
         unsafe {

alloc/src/vec/mod.rs

@@ -66,7 +66,7 @@ use core::ptr::{self, NonNull};
 use core::slice::{self, SliceIndex};
 use core::{fmt, intrinsics};
 
-#[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+#[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
 pub use self::extract_if::ExtractIf;
 use crate::alloc::{Allocator, Global};
 use crate::borrow::{Cow, ToOwned};
@@ -355,11 +355,20 @@ mod spec_extend;
 /// and it may prove desirable to use a non-constant growth factor. Whatever
 /// strategy is used will of course guarantee *O*(1) amortized [`push`].
 ///
-/// `vec![x; n]`, `vec![a, b, c, d]`, and
-/// [`Vec::with_capacity(n)`][`Vec::with_capacity`], will all produce a `Vec`
-/// with at least the requested capacity. If <code>[len] == [capacity]</code>,
-/// (as is the case for the [`vec!`] macro), then a `Vec<T>` can be converted to
-/// and from a [`Box<[T]>`][owned slice] without reallocating or moving the elements.
+/// It is guaranteed, in order to respect the intentions of the programmer, that
+/// all of `vec![e_1, e_2, ..., e_n]`, `vec![x; n]`, and [`Vec::with_capacity(n)`] produce a `Vec`
+/// that requests an allocation of the exact size needed for precisely `n` elements from the allocator,
+/// and no other size (such as, for example: a size rounded up to the nearest power of 2).
+/// The allocator will return an allocation that is at least as large as requested, but it may be larger.
+///
+/// It is guaranteed that the [`Vec::capacity`] method returns a value that is at least the requested capacity
+/// and not more than the allocated capacity.
+///
+/// The method [`Vec::shrink_to_fit`] will attempt to discard excess capacity an allocator has given to a `Vec`.
+/// If <code>[len] == [capacity]</code>, then a `Vec<T>` can be converted
+/// to and from a [`Box<[T]>`][owned slice] without reallocating or moving the elements.
+/// `Vec` exploits this fact as much as reasonable when implementing common conversions
+/// such as [`into_boxed_slice`].
 ///
 /// `Vec` will not specifically overwrite any data that is removed from it,
 /// but also won't specifically preserve it. Its uninitialized memory is
@@ -383,14 +392,17 @@ mod spec_extend;
 /// [`shrink_to`]: Vec::shrink_to
 /// [capacity]: Vec::capacity
 /// [`capacity`]: Vec::capacity
+/// [`Vec::capacity`]: Vec::capacity
 /// [mem::size_of::\<T>]: core::mem::size_of
 /// [len]: Vec::len
 /// [`len`]: Vec::len
 /// [`push`]: Vec::push
 /// [`insert`]: Vec::insert
 /// [`reserve`]: Vec::reserve
+/// [`Vec::with_capacity(n)`]: Vec::with_capacity
 /// [`MaybeUninit`]: core::mem::MaybeUninit
 /// [owned slice]: Box
+/// [`into_boxed_slice`]: Vec::into_boxed_slice
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "Vec")]
 #[rustc_insignificant_dtor]
@@ -3684,7 +3696,6 @@ impl<T, A: Allocator> Vec<T, A> {
     /// Splitting an array into evens and odds, reusing the original allocation:
     ///
     /// ```
-    /// #![feature(extract_if)]
     /// let mut numbers = vec![1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15];
     ///
     /// let evens = numbers.extract_if(.., |x| *x % 2 == 0).collect::<Vec<_>>();
@@ -3697,13 +3708,12 @@ impl<T, A: Allocator> Vec<T, A> {
     /// Using the range argument to only process a part of the vector:
     ///
     /// ```
-    /// #![feature(extract_if)]
     /// let mut items = vec![0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 2, 1, 2];
     /// let ones = items.extract_if(7.., |x| *x == 1).collect::<Vec<_>>();
     /// assert_eq!(items, vec![0, 0, 0, 0, 0, 0, 0, 2, 2, 2]);
     /// assert_eq!(ones.len(), 3);
     /// ```
-    #[unstable(feature = "extract_if", reason = "recently added", issue = "43244")]
+    #[stable(feature = "extract_if", since = "CURRENT_RUSTC_VERSION")]
     pub fn extract_if<F, R>(&mut self, range: R, filter: F) -> ExtractIf<'_, T, F, A>
     where
         F: FnMut(&mut T) -> bool,

alloc/tests/lib.rs

@@ -7,7 +7,6 @@
 #![feature(cow_is_borrowed)]
 #![feature(core_intrinsics)]
 #![feature(downcast_unchecked)]
-#![feature(extract_if)]
 #![feature(exact_size_is_empty)]
 #![feature(hashmap_internals)]
 #![feature(linked_list_cursors)]
@@ -29,7 +28,6 @@
 #![feature(string_remove_matches)]
 #![feature(const_btree_len)]
 #![feature(const_trait_impl)]
-#![feature(const_str_from_utf8)]
 #![feature(panic_update_hook)]
 #![feature(pointer_is_aligned_to)]
 #![feature(test)]

core/src/mem/maybe_uninit.rs

@@ -1041,7 +1041,6 @@ impl<T> MaybeUninit<T> {
 
     /// Deprecated version of [`slice::assume_init_ref`].
     #[unstable(feature = "maybe_uninit_slice", issue = "63569")]
-    #[rustc_const_unstable(feature = "maybe_uninit_slice", issue = "63569")]
     #[deprecated(
         note = "replaced by inherent assume_init_ref method; will eventually be removed",
         since = "1.83.0"
@@ -1053,7 +1052,6 @@ impl<T> MaybeUninit<T> {
 
     /// Deprecated version of [`slice::assume_init_mut`].
     #[unstable(feature = "maybe_uninit_slice", issue = "63569")]
-    #[rustc_const_unstable(feature = "maybe_uninit_slice", issue = "63569")]
     #[deprecated(
         note = "replaced by inherent assume_init_mut method; will eventually be removed",
         since = "1.83.0"
@@ -1326,7 +1324,6 @@ impl<T> [MaybeUninit<T>] {
     ///
     /// [`write_clone_of_slice`]: slice::write_clone_of_slice
     #[unstable(feature = "maybe_uninit_write_slice", issue = "79995")]
-    #[rustc_const_unstable(feature = "maybe_uninit_write_slice", issue = "79995")]
     pub const fn write_copy_of_slice(&mut self, src: &[T]) -> &mut [T]
     where
         T: Copy,

core/src/slice/mod.rs

@@ -956,7 +956,6 @@ impl<T> [T] {
     /// [`swap`]: slice::swap
     /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
     #[unstable(feature = "slice_swap_unchecked", issue = "88539")]
-    #[rustc_const_unstable(feature = "slice_swap_unchecked", issue = "88539")]
     pub const unsafe fn swap_unchecked(&mut self, a: usize, b: usize) {
         assert_unsafe_precondition!(
             check_library_ub,
@@ -3734,6 +3733,7 @@ impl<T> [T] {
     #[inline]
     #[stable(feature = "copy_from_slice", since = "1.9.0")]
     #[rustc_const_unstable(feature = "const_copy_from_slice", issue = "131415")]
+    #[rustc_const_stable_indirect]
     #[track_caller]
     pub const fn copy_from_slice(&mut self, src: &[T])
     where

core/src/str/converts.rs

@@ -126,7 +126,7 @@ pub const fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error> {
 /// See the docs for [`Utf8Error`] for more details on the kinds of
 /// errors that can be returned.
 #[stable(feature = "str_mut_extras", since = "1.20.0")]
-#[rustc_const_unstable(feature = "const_str_from_utf8", issue = "91006")]
+#[rustc_const_stable(feature = "const_str_from_utf8", since = "CURRENT_RUSTC_VERSION")]
 #[rustc_diagnostic_item = "str_from_utf8_mut"]
 pub const fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error> {
     // FIXME(const-hack): This should use `?` again, once it's `const`

core/src/str/mod.rs

@@ -265,7 +265,7 @@ impl str {
     /// See the docs for [`Utf8Error`] for more details on the kinds of
     /// errors that can be returned.
     #[stable(feature = "inherent_str_constructors", since = "CURRENT_RUSTC_VERSION")]
-    #[rustc_const_unstable(feature = "const_str_from_utf8", issue = "91006")]
+    #[rustc_const_stable(feature = "const_str_from_utf8", since = "CURRENT_RUSTC_VERSION")]
     #[rustc_diagnostic_item = "str_inherent_from_utf8_mut"]
     pub const fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error> {
         converts::from_utf8_mut(v)

std/src/collections/hash/map.rs

@@ -656,7 +656,6 @@ impl<K, V, S> HashMap<K, V, S> {
     /// Splitting a map into even and odd keys, reusing the original map:
     ///
     /// ```
-    /// #![feature(hash_extract_if)]
     /// use std::collections::HashMap;
     ///
     /// let mut map: HashMap<i32, i32> = (0..8).map(|x| (x, x)).collect();
@@ -672,7 +671,7 @@ impl<K, V, S> HashMap<K, V, S> {
     /// ```
     #[inline]
     #[rustc_lint_query_instability]
-    #[unstable(feature = "hash_extract_if", issue = "59618")]
+    #[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
     pub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, K, V, F>
     where
         F: FnMut(&K, &mut V) -> bool,
@@ -1722,16 +1721,14 @@ impl<'a, K, V> Drain<'a, K, V> {
 /// # Example
 ///
 /// ```
-/// #![feature(hash_extract_if)]
-///
 /// use std::collections::HashMap;
 ///
 /// let mut map = HashMap::from([
 ///     ("a", 1),
 /// ]);
 /// let iter = map.extract_if(|_k, v| *v % 2 == 0);
 /// ```
-#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
 #[must_use = "iterators are lazy and do nothing unless consumed"]
 pub struct ExtractIf<'a, K, V, F>
 where
@@ -2746,7 +2743,7 @@ where
     }
 }
 
-#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<K, V, F> Iterator for ExtractIf<'_, K, V, F>
 where
     F: FnMut(&K, &mut V) -> bool,
@@ -2763,10 +2760,10 @@ where
     }
 }
 
-#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<K, V, F> FusedIterator for ExtractIf<'_, K, V, F> where F: FnMut(&K, &mut V) -> bool {}
 
-#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<'a, K, V, F> fmt::Debug for ExtractIf<'a, K, V, F>
 where
     F: FnMut(&K, &mut V) -> bool,

std/src/collections/hash/set.rs

@@ -293,7 +293,6 @@ impl<T, S> HashSet<T, S> {
     /// Splitting a set into even and odd values, reusing the original set:
     ///
     /// ```
-    /// #![feature(hash_extract_if)]
     /// use std::collections::HashSet;
     ///
     /// let mut set: HashSet<i32> = (0..8).collect();
@@ -309,7 +308,7 @@ impl<T, S> HashSet<T, S> {
     /// ```
     #[inline]
     #[rustc_lint_query_instability]
-    #[unstable(feature = "hash_extract_if", issue = "59618")]
+    #[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
     pub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, T, F>
     where
         F: FnMut(&T) -> bool,
@@ -1385,15 +1384,13 @@ pub struct Drain<'a, K: 'a> {
 /// # Examples
 ///
 /// ```
-/// #![feature(hash_extract_if)]
-///
 /// use std::collections::HashSet;
 ///
 /// let mut a = HashSet::from([1, 2, 3]);
 ///
 /// let mut extract_ifed = a.extract_if(|v| v % 2 == 0);
 /// ```
-#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
 pub struct ExtractIf<'a, K, F>
 where
     F: FnMut(&K) -> bool,
@@ -1676,7 +1673,7 @@ impl<K: fmt::Debug> fmt::Debug for Drain<'_, K> {
     }
 }
 
-#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<K, F> Iterator for ExtractIf<'_, K, F>
 where
     F: FnMut(&K) -> bool,
@@ -1693,10 +1690,10 @@ where
     }
 }
 
-#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<K, F> FusedIterator for ExtractIf<'_, K, F> where F: FnMut(&K) -> bool {}
 
-#[unstable(feature = "hash_extract_if", issue = "59618")]
+#[stable(feature = "hash_extract_if", since = "CURRENT_RUSTC_VERSION")]
 impl<'a, K, F> fmt::Debug for ExtractIf<'a, K, F>
 where
     F: FnMut(&K) -> bool,

std/src/sys/pal/zkvm/stdio.rs

@@ -1,6 +1,6 @@
 use super::abi;
 use super::abi::fileno;
-use crate::io;
+use crate::io::{self, BorrowedCursor};
 
 pub struct Stdin;
 pub struct Stdout;
@@ -16,6 +16,14 @@ impl io::Read for Stdin {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         Ok(unsafe { abi::sys_read(fileno::STDIN, buf.as_mut_ptr(), buf.len()) })
     }
+
+    fn read_buf(&mut self, mut buf: BorrowedCursor<'_>) -> io::Result<()> {
+        unsafe {
+            let n = abi::sys_read(fileno::STDIN, buf.as_mut().as_mut_ptr().cast(), buf.capacity());
+            buf.advance_unchecked(n);
+        }
+        Ok(())
+    }
 }
 
 impl Stdout {