Rollup of 11 pull requests

Cargo.lock

@@ -1366,9 +1366,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.15"
+version = "0.1.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3deed196b6e7f9e44a2ae8d94225d80302d81208b1bb673fd21fe634645c85a9"
+checksum = "5aca5565f760fb5b220e499d72710ed156fdb74e631659e99377d9ebfbd13ae8"
 dependencies = [
  "compiler_builtins",
  "libc",

compiler/rustc_middle/src/infer/unify_key.rs

@@ -175,19 +175,15 @@ impl<'tcx> UnifyKey for ty::ConstVid<'tcx> {
 impl<'tcx> UnifyValue for ConstVarValue<'tcx> {
     type Error = (&'tcx ty::Const<'tcx>, &'tcx ty::Const<'tcx>);
 
-    fn unify_values(value1: &Self, value2: &Self) -> Result<Self, Self::Error> {
-        let (val, span) = match (value1.val, value2.val) {
+    fn unify_values(&value1: &Self, &value2: &Self) -> Result<Self, Self::Error> {
+        Ok(match (value1.val, value2.val) {
             (ConstVariableValue::Known { .. }, ConstVariableValue::Known { .. }) => {
                 bug!("equating two const variables, both of which have known values")
             }
 
             // If one side is known, prefer that one.
-            (ConstVariableValue::Known { .. }, ConstVariableValue::Unknown { .. }) => {
-                (value1.val, value1.origin.span)
-            }
-            (ConstVariableValue::Unknown { .. }, ConstVariableValue::Known { .. }) => {
-                (value2.val, value2.origin.span)
-            }
+            (ConstVariableValue::Known { .. }, ConstVariableValue::Unknown { .. }) => value1,
+            (ConstVariableValue::Unknown { .. }, ConstVariableValue::Known { .. }) => value2,
 
             // If both sides are *unknown*, it hardly matters, does it?
             (
@@ -200,16 +196,11 @@ impl<'tcx> UnifyValue for ConstVarValue<'tcx> {
                 // universe is the minimum of the two universes, because that is
                 // the one which contains the fewest names in scope.
                 let universe = cmp::min(universe1, universe2);
-                (ConstVariableValue::Unknown { universe }, value1.origin.span)
+                ConstVarValue {
+                    val: ConstVariableValue::Unknown { universe },
+                    origin: value1.origin,
+                }
             }
-        };
-
-        Ok(ConstVarValue {
-            origin: ConstVariableOrigin {
-                kind: ConstVariableOriginKind::ConstInference,
-                span: span,
-            },
-            val,
         })
     }
 }

compiler/rustc_mir/src/transform/simplify_branches.rs

@@ -49,9 +49,10 @@ impl<'tcx> MirPass<'tcx> for SimplifyBranches {
                 }
                 TerminatorKind::Assert {
                     target, cond: Operand::Constant(ref c), expected, ..
-                } if (c.literal.try_eval_bool(tcx, param_env) == Some(true)) == expected => {
-                    TerminatorKind::Goto { target }
-                }
+                } => match c.literal.try_eval_bool(tcx, param_env) {
+                    Some(v) if v == expected => TerminatorKind::Goto { target },
+                    _ => continue,
+                },
                 TerminatorKind::FalseEdge { real_target, .. } => {
                     TerminatorKind::Goto { target: real_target }
                 }

compiler/rustc_target/src/spec/apple_sdk_base.rs

@@ -34,6 +34,7 @@ fn link_env_remove(arch: Arch) -> Vec<String> {
 pub fn opts(arch: Arch) -> TargetOptions {
     TargetOptions {
         cpu: target_cpu(arch),
+        dynamic_linking: false,
         executables: true,
         link_env_remove: link_env_remove(arch),
         has_elf_tls: false,

library/alloc/src/alloc.rs

@@ -372,7 +372,7 @@ pub fn handle_alloc_error(layout: Layout) -> ! {
     unsafe { oom_impl(layout) }
 }
 
-#[cfg(not(any(test, bootstrap)))]
+#[cfg(not(any(target_os = "hermit", test, bootstrap)))]
 #[doc(hidden)]
 #[allow(unused_attributes)]
 #[unstable(feature = "alloc_internals", issue = "none")]

library/alloc/src/lib.rs

@@ -118,6 +118,7 @@
 #![feature(raw_ref_op)]
 #![feature(rustc_attrs)]
 #![feature(receiver_trait)]
+#![feature(renamed_spin_loop)]
 #![feature(min_specialization)]
 #![feature(slice_ptr_get)]
 #![feature(slice_ptr_len)]

library/alloc/src/sync.rs

@@ -10,6 +10,7 @@ use core::cmp::Ordering;
 use core::convert::{From, TryFrom};
 use core::fmt;
 use core::hash::{Hash, Hasher};
+use core::hint;
 use core::intrinsics::abort;
 use core::iter;
 use core::marker::{PhantomData, Unpin, Unsize};
@@ -764,6 +765,7 @@ impl<T: ?Sized> Arc<T> {
         loop {
             // check if the weak counter is currently "locked"; if so, spin.
             if cur == usize::MAX {
+                hint::spin_loop();
                 cur = this.inner().weak.load(Relaxed);
                 continue;
             }

library/alloc/tests/str.rs

@@ -529,6 +529,13 @@ mod slice_index {
             message: "out of bounds";
         }
 
+        in mod rangeinclusive_len {
+            data: "abcdef";
+            good: data[0..=5] == "abcdef";
+            bad: data[0..=6];
+            message: "out of bounds";
+        }
+
         in mod range_len_len {
             data: "abcdef";
             good: data[6..6] == "";
@@ -544,6 +551,28 @@ mod slice_index {
         }
     }
 
+    panic_cases! {
+        in mod rangeinclusive_exhausted {
+            data: "abcdef";
+
+            good: data[0..=5] == "abcdef";
+            good: data[{
+                let mut iter = 0..=5;
+                iter.by_ref().count(); // exhaust it
+                iter
+            }] == "";
+
+            // 0..=6 is out of bounds before exhaustion, so it
+            // stands to reason that it still would be after.
+            bad: data[{
+                let mut iter = 0..=6;
+                iter.by_ref().count(); // exhaust it
+                iter
+            }];
+            message: "out of bounds";
+        }
+    }
+
     panic_cases! {
         in mod range_neg_width {
             data: "abcdef";

library/core/src/ops/range.rs

@@ -446,6 +446,20 @@ impl<Idx> RangeInclusive<Idx> {
     }
 }
 
+impl RangeInclusive<usize> {
+    /// Converts to an exclusive `Range` for `SliceIndex` implementations.
+    /// The caller is responsible for dealing with `end == usize::MAX`.
+    #[inline]
+    pub(crate) fn into_slice_range(self) -> Range<usize> {
+        // If we're not exhausted, we want to simply slice `start..end + 1`.
+        // If we are exhausted, then slicing with `end + 1..end + 1` gives us an
+        // empty range that is still subject to bounds-checks for that endpoint.
+        let exclusive_end = self.end + 1;
+        let start = if self.exhausted { exclusive_end } else { self.start };
+        start..exclusive_end
+    }
+}
+
 #[stable(feature = "inclusive_range", since = "1.26.0")]
 impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -479,6 +493,16 @@ impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
     /// assert!(!(0.0..=f32::NAN).contains(&0.0));
     /// assert!(!(f32::NAN..=1.0).contains(&1.0));
     /// ```
+    ///
+    /// This method always returns `false` after iteration has finished:
+    ///
+    /// ```
+    /// let mut r = 3..=5;
+    /// assert!(r.contains(&3) && r.contains(&5));
+    /// for _ in r.by_ref() {}
+    /// // Precise field values are unspecified here
+    /// assert!(!r.contains(&3) && !r.contains(&5));
+    /// ```
     #[stable(feature = "range_contains", since = "1.35.0")]
     pub fn contains<U>(&self, item: &U) -> bool
     where
@@ -881,7 +905,13 @@ impl<T> RangeBounds<T> for RangeInclusive<T> {
         Included(&self.start)
     }
     fn end_bound(&self) -> Bound<&T> {
-        Included(&self.end)
+        if self.exhausted {
+            // When the iterator is exhausted, we usually have start == end,
+            // but we want the range to appear empty, containing nothing.
+            Excluded(&self.end)
+        } else {
+            Included(&self.end)
+        }
     }
 }
 

library/core/src/option.rs

@@ -562,6 +562,36 @@ impl<T> Option<T> {
         }
     }
 
+    /// Inserts `value` into the option then returns a mutable reference to it.
+    ///
+    /// If the option already contains a value, the old value is dropped.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// #![feature(option_insert)]
+    ///
+    /// let mut opt = None;
+    /// let val = opt.insert(1);
+    /// assert_eq!(*val, 1);
+    /// assert_eq!(opt.unwrap(), 1);
+    /// let val = opt.insert(2);
+    /// assert_eq!(*val, 2);
+    /// *val = 3;
+    /// assert_eq!(opt.unwrap(), 3);
+    /// ```
+    #[inline]
+    #[unstable(feature = "option_insert", reason = "newly added", issue = "78271")]
+    pub fn insert(&mut self, value: T) -> &mut T {
+        *self = Some(value);
+
+        match self {
+            Some(v) => v,
+            // SAFETY: the code above just filled the option
+            None => unsafe { hint::unreachable_unchecked() },
+        }
+    }
+
     /////////////////////////////////////////////////////////////////////////
     // Iterator constructors
     /////////////////////////////////////////////////////////////////////////
@@ -792,7 +822,7 @@ impl<T> Option<T> {
     // Entry-like operations to insert if None and return a reference
     /////////////////////////////////////////////////////////////////////////
 
-    /// Inserts `v` into the option if it is [`None`], then
+    /// Inserts `value` into the option if it is [`None`], then
     /// returns a mutable reference to the contained value.
     ///
     /// # Examples
@@ -811,12 +841,12 @@ impl<T> Option<T> {
     /// ```
     #[inline]
     #[stable(feature = "option_entry", since = "1.20.0")]
-    pub fn get_or_insert(&mut self, v: T) -> &mut T {
-        self.get_or_insert_with(|| v)
+    pub fn get_or_insert(&mut self, value: T) -> &mut T {
+        self.get_or_insert_with(|| value)
     }
 
-    /// Inserts a value computed from `f` into the option if it is [`None`], then
-    /// returns a mutable reference to the contained value.
+    /// Inserts a value computed from `f` into the option if it is [`None`],
+    /// then returns a mutable reference to the contained value.
     ///
     /// # Examples
     ///
@@ -839,8 +869,8 @@ impl<T> Option<T> {
             *self = Some(f());
         }
 
-        match *self {
-            Some(ref mut v) => v,
+        match self {
+            Some(v) => v,
             // SAFETY: a `None` variant for `self` would have been replaced by a `Some`
             // variant in the code above.
             None => unsafe { hint::unreachable_unchecked() },

library/core/src/slice/index.rs

@@ -376,44 +376,40 @@ unsafe impl<T> SliceIndex<[T]> for ops::RangeInclusive<usize> {
 
     #[inline]
     fn get(self, slice: &[T]) -> Option<&[T]> {
-        if *self.end() == usize::MAX { None } else { (*self.start()..self.end() + 1).get(slice) }
+        if *self.end() == usize::MAX { None } else { self.into_slice_range().get(slice) }
     }
 
     #[inline]
     fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]> {
-        if *self.end() == usize::MAX {
-            None
-        } else {
-            (*self.start()..self.end() + 1).get_mut(slice)
-        }
+        if *self.end() == usize::MAX { None } else { self.into_slice_range().get_mut(slice) }
     }
 
     #[inline]
     unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T] {
         // SAFETY: the caller has to uphold the safety contract for `get_unchecked`.
-        unsafe { (*self.start()..self.end() + 1).get_unchecked(slice) }
+        unsafe { self.into_slice_range().get_unchecked(slice) }
     }
 
     #[inline]
     unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T] {
         // SAFETY: the caller has to uphold the safety contract for `get_unchecked_mut`.
-        unsafe { (*self.start()..self.end() + 1).get_unchecked_mut(slice) }
+        unsafe { self.into_slice_range().get_unchecked_mut(slice) }
     }
 
     #[inline]
     fn index(self, slice: &[T]) -> &[T] {
         if *self.end() == usize::MAX {
             slice_end_index_overflow_fail();
         }
-        (*self.start()..self.end() + 1).index(slice)
+        self.into_slice_range().index(slice)
     }
 
     #[inline]
     fn index_mut(self, slice: &mut [T]) -> &mut [T] {
         if *self.end() == usize::MAX {
             slice_end_index_overflow_fail();
         }
-        (*self.start()..self.end() + 1).index_mut(slice)
+        self.into_slice_range().index_mut(slice)
     }
 }
 

library/core/src/str/traits.rs

@@ -398,39 +398,35 @@ unsafe impl SliceIndex<str> for ops::RangeInclusive<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
-        if *self.end() == usize::MAX { None } else { (*self.start()..self.end() + 1).get(slice) }
+        if *self.end() == usize::MAX { None } else { self.into_slice_range().get(slice) }
     }
     #[inline]
     fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
-        if *self.end() == usize::MAX {
-            None
-        } else {
-            (*self.start()..self.end() + 1).get_mut(slice)
-        }
+        if *self.end() == usize::MAX { None } else { self.into_slice_range().get_mut(slice) }
     }
     #[inline]
     unsafe fn get_unchecked(self, slice: *const str) -> *const Self::Output {
         // SAFETY: the caller must uphold the safety contract for `get_unchecked`.
-        unsafe { (*self.start()..self.end() + 1).get_unchecked(slice) }
+        unsafe { self.into_slice_range().get_unchecked(slice) }
     }
     #[inline]
     unsafe fn get_unchecked_mut(self, slice: *mut str) -> *mut Self::Output {
         // SAFETY: the caller must uphold the safety contract for `get_unchecked_mut`.
-        unsafe { (*self.start()..self.end() + 1).get_unchecked_mut(slice) }
+        unsafe { self.into_slice_range().get_unchecked_mut(slice) }
     }
     #[inline]
     fn index(self, slice: &str) -> &Self::Output {
         if *self.end() == usize::MAX {
             str_index_overflow_fail();
         }
-        (*self.start()..self.end() + 1).index(slice)
+        self.into_slice_range().index(slice)
     }
     #[inline]
     fn index_mut(self, slice: &mut str) -> &mut Self::Output {
         if *self.end() == usize::MAX {
             str_index_overflow_fail();
         }
-        (*self.start()..self.end() + 1).index_mut(slice)
+        self.into_slice_range().index_mut(slice)
     }
 }