Constify RangeBounds, RangeX::contains and RangeX::is_empty.

Author: onestacked

library/core/src/cmp.rs

@@ -1491,9 +1491,10 @@ mod impls {
         }
     }
     #[stable(feature = "rust1", since = "1.0.0")]
-    impl<A: ?Sized, B: ?Sized> PartialOrd<&B> for &A
+    #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+    impl<A: ?Sized, B: ?Sized> const PartialOrd<&B> for &A
     where
-        A: PartialOrd<B>,
+        A: ~const PartialOrd<B>,
     {
         #[inline]
         fn partial_cmp(&self, other: &&B) -> Option<Ordering> {

library/core/src/ops/range.rs

@@ -96,7 +96,7 @@ impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> {
     }
 }
 
-impl<Idx: PartialOrd<Idx>> Range<Idx> {
+impl<Idx: ~const PartialOrd<Idx>> Range<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
@@ -116,10 +116,11 @@ impl<Idx: PartialOrd<Idx>> Range<Idx> {
     /// assert!(!(f32::NAN..1.0).contains(&0.5));
     /// ```
     #[stable(feature = "range_contains", since = "1.35.0")]
-    pub fn contains<U>(&self, item: &U) -> bool
+    #[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+    pub const fn contains<U>(&self, item: &U) -> bool
     where
-        Idx: PartialOrd<U>,
-        U: ?Sized + PartialOrd<Idx>,
+        Idx: ~const PartialOrd<U>,
+        U: ?Sized + ~const PartialOrd<Idx>,
     {
         <Self as RangeBounds<Idx>>::contains(self, item)
     }
@@ -142,7 +143,8 @@ impl<Idx: PartialOrd<Idx>> Range<Idx> {
     /// assert!( (f32::NAN..5.0).is_empty());
     /// ```
     #[stable(feature = "range_is_empty", since = "1.47.0")]
-    pub fn is_empty(&self) -> bool {
+    #[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+    pub const fn is_empty(&self) -> bool {
         !(self.start < self.end)
     }
 }
@@ -199,7 +201,7 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> {
     }
 }
 
-impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
+impl<Idx: ~const PartialOrd<Idx>> RangeFrom<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
@@ -214,10 +216,11 @@ impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
     /// assert!(!(f32::NAN..).contains(&0.5));
     /// ```
     #[stable(feature = "range_contains", since = "1.35.0")]
-    pub fn contains<U>(&self, item: &U) -> bool
+    #[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+    pub const fn contains<U>(&self, item: &U) -> bool
     where
-        Idx: PartialOrd<U>,
-        U: ?Sized + PartialOrd<Idx>,
+        Idx: ~const PartialOrd<U>,
+        U: ?Sized + ~const PartialOrd<Idx>,
     {
         <Self as RangeBounds<Idx>>::contains(self, item)
     }
@@ -280,7 +283,7 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeTo<Idx> {
     }
 }
 
-impl<Idx: PartialOrd<Idx>> RangeTo<Idx> {
+impl<Idx: ~const PartialOrd<Idx>> RangeTo<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
@@ -295,10 +298,11 @@ impl<Idx: PartialOrd<Idx>> RangeTo<Idx> {
     /// assert!(!(..f32::NAN).contains(&0.5));
     /// ```
     #[stable(feature = "range_contains", since = "1.35.0")]
-    pub fn contains<U>(&self, item: &U) -> bool
+    #[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+    pub const fn contains<U>(&self, item: &U) -> bool
     where
-        Idx: PartialOrd<U>,
-        U: ?Sized + PartialOrd<Idx>,
+        Idx: ~const PartialOrd<U>,
+        U: ?Sized + ~const PartialOrd<Idx>,
     {
         <Self as RangeBounds<Idx>>::contains(self, item)
     }
@@ -437,7 +441,8 @@ impl<Idx> RangeInclusive<Idx> {
     /// ```
     #[stable(feature = "inclusive_range_methods", since = "1.27.0")]
     #[inline]
-    pub fn into_inner(self) -> (Idx, Idx) {
+    #[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+    pub const fn into_inner(self) -> (Idx, Idx) {
         (self.start, self.end)
     }
 }
@@ -469,7 +474,7 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> {
     }
 }
 
-impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
+impl<Idx: ~const PartialOrd<Idx>> RangeInclusive<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
@@ -500,10 +505,11 @@ impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
     /// assert!(!r.contains(&3) && !r.contains(&5));
     /// ```
     #[stable(feature = "range_contains", since = "1.35.0")]
-    pub fn contains<U>(&self, item: &U) -> bool
+    #[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+    pub const fn contains<U>(&self, item: &U) -> bool
     where
-        Idx: PartialOrd<U>,
-        U: ?Sized + PartialOrd<Idx>,
+        Idx: ~const PartialOrd<U>,
+        U: ?Sized + ~const PartialOrd<Idx>,
     {
         <Self as RangeBounds<Idx>>::contains(self, item)
     }
@@ -535,8 +541,9 @@ impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
     /// assert!(r.is_empty());
     /// ```
     #[stable(feature = "range_is_empty", since = "1.47.0")]
+    #[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
     #[inline]
-    pub fn is_empty(&self) -> bool {
+    pub const fn is_empty(&self) -> bool {
         self.exhausted || !(self.start <= self.end)
     }
 }
@@ -598,7 +605,7 @@ impl<Idx: fmt::Debug> fmt::Debug for RangeToInclusive<Idx> {
     }
 }
 
-impl<Idx: PartialOrd<Idx>> RangeToInclusive<Idx> {
+impl<Idx: ~const PartialOrd<Idx>> RangeToInclusive<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
@@ -613,10 +620,11 @@ impl<Idx: PartialOrd<Idx>> RangeToInclusive<Idx> {
     /// assert!(!(..=f32::NAN).contains(&0.5));
     /// ```
     #[stable(feature = "range_contains", since = "1.35.0")]
-    pub fn contains<U>(&self, item: &U) -> bool
+    #[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+    pub const fn contains<U>(&self, item: &U) -> bool
     where
-        Idx: PartialOrd<U>,
-        U: ?Sized + PartialOrd<Idx>,
+        Idx: ~const PartialOrd<U>,
+        U: ?Sized + ~const PartialOrd<Idx>,
     {
         <Self as RangeBounds<Idx>>::contains(self, item)
     }
@@ -757,6 +765,7 @@ impl<T: Clone> Bound<&T> {
 /// `RangeBounds` is implemented by Rust's built-in range types, produced
 /// by range syntax like `..`, `a..`, `..b`, `..=c`, `d..e`, or `f..=g`.
 #[stable(feature = "collections_range", since = "1.28.0")]
+#[const_trait]
 pub trait RangeBounds<T: ?Sized> {
     /// Start index bound.
     ///
@@ -809,8 +818,8 @@ pub trait RangeBounds<T: ?Sized> {
     #[stable(feature = "range_contains", since = "1.35.0")]
     fn contains<U>(&self, item: &U) -> bool
     where
-        T: PartialOrd<U>,
-        U: ?Sized + PartialOrd<T>,
+        T: ~const PartialOrd<U>,
+        U: ?Sized + ~const PartialOrd<T>,
     {
         (match self.start_bound() {
             Included(start) => start <= item,
@@ -827,7 +836,8 @@ pub trait RangeBounds<T: ?Sized> {
 use self::Bound::{Excluded, Included, Unbounded};
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T: ?Sized> RangeBounds<T> for RangeFull {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T: ?Sized> const RangeBounds<T> for RangeFull {
     fn start_bound(&self) -> Bound<&T> {
         Unbounded
     }
@@ -837,7 +847,8 @@ impl<T: ?Sized> RangeBounds<T> for RangeFull {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for RangeFrom<T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for RangeFrom<T> {
     fn start_bound(&self) -> Bound<&T> {
         Included(&self.start)
     }
@@ -847,7 +858,8 @@ impl<T> RangeBounds<T> for RangeFrom<T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for RangeTo<T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for RangeTo<T> {
     fn start_bound(&self) -> Bound<&T> {
         Unbounded
     }
@@ -857,7 +869,8 @@ impl<T> RangeBounds<T> for RangeTo<T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for Range<T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for Range<T> {
     fn start_bound(&self) -> Bound<&T> {
         Included(&self.start)
     }
@@ -867,7 +880,8 @@ impl<T> RangeBounds<T> for Range<T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for RangeInclusive<T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for RangeInclusive<T> {
     fn start_bound(&self) -> Bound<&T> {
         Included(&self.start)
     }
@@ -883,7 +897,8 @@ impl<T> RangeBounds<T> for RangeInclusive<T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for RangeToInclusive<T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for RangeToInclusive<T> {
     fn start_bound(&self) -> Bound<&T> {
         Unbounded
     }
@@ -893,7 +908,8 @@ impl<T> RangeBounds<T> for RangeToInclusive<T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for (Bound<T>, Bound<T>) {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for (Bound<T>, Bound<T>) {
     fn start_bound(&self) -> Bound<&T> {
         match *self {
             (Included(ref start), _) => Included(start),
@@ -912,7 +928,8 @@ impl<T> RangeBounds<T> for (Bound<T>, Bound<T>) {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<'a, T: ?Sized + 'a> RangeBounds<T> for (Bound<&'a T>, Bound<&'a T>) {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<'a, T: ?Sized + 'a> const RangeBounds<T> for (Bound<&'a T>, Bound<&'a T>) {
     fn start_bound(&self) -> Bound<&T> {
         self.0
     }
@@ -923,7 +940,8 @@ impl<'a, T: ?Sized + 'a> RangeBounds<T> for (Bound<&'a T>, Bound<&'a T>) {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for RangeFrom<&T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for RangeFrom<&T> {
     fn start_bound(&self) -> Bound<&T> {
         Included(self.start)
     }
@@ -933,7 +951,8 @@ impl<T> RangeBounds<T> for RangeFrom<&T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for RangeTo<&T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for RangeTo<&T> {
     fn start_bound(&self) -> Bound<&T> {
         Unbounded
     }
@@ -943,7 +962,8 @@ impl<T> RangeBounds<T> for RangeTo<&T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for Range<&T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for Range<&T> {
     fn start_bound(&self) -> Bound<&T> {
         Included(self.start)
     }
@@ -953,7 +973,8 @@ impl<T> RangeBounds<T> for Range<&T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for RangeInclusive<&T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for RangeInclusive<&T> {
     fn start_bound(&self) -> Bound<&T> {
         Included(self.start)
     }
@@ -963,7 +984,8 @@ impl<T> RangeBounds<T> for RangeInclusive<&T> {
 }
 
 #[stable(feature = "collections_range", since = "1.28.0")]
-impl<T> RangeBounds<T> for RangeToInclusive<&T> {
+#[rustc_const_unstable(feature = "const_range_bounds", issue = "108082")]
+impl<T> const RangeBounds<T> for RangeToInclusive<&T> {
     fn start_bound(&self) -> Bound<&T> {
         Unbounded
     }