Auto merge of #120365 - matthiaskrgr:rollup-ly2w0d5, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #107464 (Add `str::Lines::remainder`)
 - #118803 (Add the `min_exhaustive_patterns` feature gate)
 - #119466 (Initial implementation of `str::from_raw_parts[_mut]`)
 - #120053 (Specialize `Bytes` on `StdinLock<'_>`)
 - #120124 (Split assembly tests for ELF and MachO)
 - #120204 (Builtin macros effectively have implicit #[collapse_debuginfo(yes)])
 - #120322 (Don't manually resolve async closures in `rustc_resolve`)
 - #120356 (Fix broken markdown in csky-unknown-linux-gnuabiv2.md)

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

3 files changed, 67 insertions, 1 deletions

diff --git a/library/core/src/str/converts.rs b/library/core/src/str/converts.rs
index 0f23cf7ae23..ba282f09d20 100644
--- a/library/core/src/str/converts.rs
+++ b/library/core/src/str/converts.rs
@@ -1,6 +1,6 @@
 //! Ways to create a `str` from bytes slice.
 
-use crate::mem;
+use crate::{mem, ptr};
 
 use super::validations::run_utf8_validation;
 use super::Utf8Error;
@@ -205,3 +205,41 @@ pub const unsafe fn from_utf8_unchecked_mut(v: &mut [u8]) -> &mut str {
     // comes from a reference which is guaranteed to be valid for writes.
     unsafe { &mut *(v as *mut [u8] as *mut str) }
 }
+
+/// Creates an `&str` from a pointer and a length.
+///
+/// The pointed-to bytes must be valid UTF-8.
+/// If this might not be the case, use `str::from_utf8(slice::from_raw_parts(ptr, len))`,
+/// which will return an `Err` if the data isn't valid UTF-8.
+///
+/// This function is the `str` equivalent of [`slice::from_raw_parts`](crate::slice::from_raw_parts).
+/// See that function's documentation for safety concerns and examples.
+///
+/// The mutable version of this function is [`from_raw_parts_mut`].
+#[inline]
+#[must_use]
+#[unstable(feature = "str_from_raw_parts", issue = "119206")]
+#[rustc_const_unstable(feature = "str_from_raw_parts", issue = "119206")]
+pub const unsafe fn from_raw_parts<'a>(ptr: *const u8, len: usize) -> &'a str {
+    // SAFETY: the caller must uphold the safety contract for `from_raw_parts`.
+    unsafe { &*ptr::from_raw_parts(ptr.cast(), len) }
+}
+
+/// Creates an `&mut str` from a pointer and a length.
+///
+/// The pointed-to bytes must be valid UTF-8.
+/// If this might not be the case, use `str::from_utf8_mut(slice::from_raw_parts_mut(ptr, len))`,
+/// which will return an `Err` if the data isn't valid UTF-8.
+///
+/// This function is the `str` equivalent of [`slice::from_raw_parts_mut`](crate::slice::from_raw_parts_mut).
+/// See that function's documentation for safety concerns and examples.
+///
+/// The immutable version of this function is [`from_raw_parts`].
+#[inline]
+#[must_use]
+#[unstable(feature = "str_from_raw_parts", issue = "119206")]
+#[rustc_const_unstable(feature = "const_str_from_raw_parts_mut", issue = "119206")]
+pub const unsafe fn from_raw_parts_mut<'a>(ptr: *mut u8, len: usize) -> &'a str {
+    // SAFETY: the caller must uphold the safety contract for `from_raw_parts_mut`.
+    unsafe { &mut *ptr::from_raw_parts_mut(ptr.cast(), len) }
+}
diff --git a/library/core/src/str/iter.rs b/library/core/src/str/iter.rs
index dd2efb00516..4d6239e11a3 100644
--- a/library/core/src/str/iter.rs
+++ b/library/core/src/str/iter.rs
@@ -1187,6 +1187,31 @@ impl<'a> DoubleEndedIterator for Lines<'a> {
 #[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for Lines<'_> {}
 
+impl<'a> Lines<'a> {
+    /// Returns the remaining lines of the split string.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(str_lines_remainder)]
+    ///
+    /// let mut lines = "a\nb\nc\nd".lines();
+    /// assert_eq!(lines.remainder(), Some("a\nb\nc\nd"));
+    ///
+    /// lines.next();
+    /// assert_eq!(lines.remainder(), Some("b\nc\nd"));
+    ///
+    /// lines.by_ref().for_each(drop);
+    /// assert_eq!(lines.remainder(), None);
+    /// ```
+    #[inline]
+    #[must_use]
+    #[unstable(feature = "str_lines_remainder", issue = "77998")]
+    pub fn remainder(&self) -> Option<&'a str> {
+        self.0.iter.remainder()
+    }
+}
+
 /// Created with the method [`lines_any`].
 ///
 /// [`lines_any`]: str::lines_any
diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs
index 80c5fe0de8d..ecc0613d7b9 100644
--- a/library/core/src/str/mod.rs
+++ b/library/core/src/str/mod.rs
@@ -33,6 +33,9 @@ pub use converts::{from_utf8, from_utf8_unchecked};
 #[stable(feature = "str_mut_extras", since = "1.20.0")]
 pub use converts::{from_utf8_mut, from_utf8_unchecked_mut};
 
+#[unstable(feature = "str_from_raw_parts", issue = "119206")]
+pub use converts::{from_raw_parts, from_raw_parts_mut};
+
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use error::{ParseBoolError, Utf8Error};