Merge ref 'f6d23413c399' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: f6d2341
Filtered ref: fc132ae45e682a2556f99caed7bca9b8a2e909c8

This merge was created using https://github.com/rust-lang/josh-sync.

Author: The Miri Cronjob Bot

Cargo.lock

@@ -1872,28 +1872,33 @@ pub const unsafe fn encode_utf8_raw_unchecked(code: u32, dst: *mut u8) {
     // SAFETY: The caller must guarantee that the buffer pointed to by `dst`
     // is at least `len` bytes long.
     unsafe {
-        match len {
-            1 => {
-                *dst = code as u8;
-            }
-            2 => {
-                *dst = (code >> 6 & 0x1F) as u8 | TAG_TWO_B;
-                *dst.add(1) = (code & 0x3F) as u8 | TAG_CONT;
-            }
-            3 => {
-                *dst = (code >> 12 & 0x0F) as u8 | TAG_THREE_B;
-                *dst.add(1) = (code >> 6 & 0x3F) as u8 | TAG_CONT;
-                *dst.add(2) = (code & 0x3F) as u8 | TAG_CONT;
-            }
-            4 => {
-                *dst = (code >> 18 & 0x07) as u8 | TAG_FOUR_B;
-                *dst.add(1) = (code >> 12 & 0x3F) as u8 | TAG_CONT;
-                *dst.add(2) = (code >> 6 & 0x3F) as u8 | TAG_CONT;
-                *dst.add(3) = (code & 0x3F) as u8 | TAG_CONT;
-            }
-            // SAFETY: `char` always takes between 1 and 4 bytes to encode in UTF-8.
-            _ => crate::hint::unreachable_unchecked(),
+        if len == 1 {
+            *dst = code as u8;
+            return;
+        }
+
+        let last1 = (code >> 0 & 0x3F) as u8 | TAG_CONT;
+        let last2 = (code >> 6 & 0x3F) as u8 | TAG_CONT;
+        let last3 = (code >> 12 & 0x3F) as u8 | TAG_CONT;
+        let last4 = (code >> 18 & 0x3F) as u8 | TAG_FOUR_B;
+
+        if len == 2 {
+            *dst = last2 | TAG_TWO_B;
+            *dst.add(1) = last1;
+            return;
         }
+
+        if len == 3 {
+            *dst = last3 | TAG_THREE_B;
+            *dst.add(1) = last2;
+            *dst.add(2) = last1;
+            return;
+        }
+
+        *dst = last4;
+        *dst.add(1) = last3;
+        *dst.add(2) = last2;
+        *dst.add(3) = last1;
     }
 }
 

core/src/char/methods.rs

@@ -172,6 +172,7 @@
 #![feature(no_core)]
 #![feature(optimize_attribute)]
 #![feature(prelude_import)]
+#![feature(reborrow)]
 #![feature(repr_simd)]
 #![feature(rustc_allow_const_fn_unstable)]
 #![feature(rustc_attrs)]

core/src/lib.rs

@@ -1365,3 +1365,11 @@ pub macro CoercePointee($item:item) {
 pub trait CoercePointeeValidated {
     /* compiler built-in */
 }
+
+/// Allows value to be reborrowed as exclusive, creating a copy of the value
+/// that disables the source for reads and writes for the lifetime of the copy.
+#[lang = "reborrow"]
+#[unstable(feature = "reborrow", issue = "145612")]
+pub trait Reborrow {
+    // Empty.
+}

core/src/marker.rs

@@ -183,7 +183,7 @@ impl<'a> Location<'a> {
     #[must_use]
     #[stable(feature = "panic_hooks", since = "1.10.0")]
     #[rustc_const_stable(feature = "const_location_fields", since = "1.79.0")]
-    pub const fn file(&self) -> &str {
+    pub const fn file(&self) -> &'a str {
         // SAFETY: The filename is valid.
         unsafe { self.filename.as_ref() }
     }
@@ -195,7 +195,7 @@ impl<'a> Location<'a> {
     #[must_use]
     #[unstable(feature = "file_with_nul", issue = "141727")]
     #[inline]
-    pub const fn file_with_nul(&self) -> &CStr {
+    pub const fn file_with_nul(&self) -> &'a CStr {
         let filename = self.filename.as_ptr();
 
         // SAFETY: The filename is valid for `filename_len+1` bytes, so this addition can't

core/src/panic/location.rs

@@ -47,11 +47,19 @@ fn location_const_column() {
     assert_eq!(COLUMN, 40);
 }
 
+#[test]
+fn location_file_lifetime<'x>() {
+    // Verify that the returned `&str`s lifetime is derived from the generic
+    // lifetime 'a, not the lifetime of `&self`, when calling `Location::file`.
+    // Test failure is indicated by a compile failure, not a runtime panic.
+    let _: for<'a> fn(&'a Location<'x>) -> &'x str = Location::file;
+}
+
 #[test]
 fn location_debug() {
     let f = format!("{:?}", Location::caller());
     assert!(f.contains(&format!("{:?}", file!())));
-    assert!(f.contains("52"));
+    assert!(f.contains("60"));
     assert!(f.contains("29"));
 }
 

coretests/tests/panic/location.rs

@@ -33,5 +33,10 @@ impl fmt::Display for WouldBlock {
 pub use self::mutex::MappedMutexGuard;
 #[unstable(feature = "nonpoison_mutex", issue = "134645")]
 pub use self::mutex::{Mutex, MutexGuard};
+#[unstable(feature = "mapped_lock_guards", issue = "117108")]
+pub use self::rwlock::{MappedRwLockReadGuard, MappedRwLockWriteGuard};
+#[unstable(feature = "nonpoison_rwlock", issue = "134645")]
+pub use self::rwlock::{RwLock, RwLockReadGuard, RwLockWriteGuard};
 
 mod mutex;
+mod rwlock;