src/libcore/ops/range.rs - rust - Git at Google

 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.

 use fmt;

 /// An unbounded range (`..`).
 ///
 /// `RangeFull` is primarily used as a [slicing index], its shorthand is `..`.
 /// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
 ///
 /// # Examples
 ///
 /// The `..` syntax is a `RangeFull`:
 ///
 /// ```
 /// assert_eq!((..), std::ops::RangeFull);
 /// ```
 ///
 /// It does not have an [`IntoIterator`] implementation, so you can't use it in
 /// a `for` loop directly. This won't compile:
 ///
 /// ```compile_fail,E0277
 /// for i in .. {
 ///    // ...
 /// }
 /// ```
 ///
 /// Used as a [slicing index], `RangeFull` produces the full array as a slice.
 ///
 /// ```
 /// let arr = [0, 1, 2, 3];
 /// assert_eq!(arr[ .. ], [0,1,2,3]);  // RangeFull
 /// assert_eq!(arr[ ..3], [0,1,2  ]);
 /// assert_eq!(arr[1.. ], [  1,2,3]);
 /// assert_eq!(arr[1..3], [  1,2  ]);
 /// ```
 ///
 /// [`IntoIterator`]: ../iter/trait.Iterator.html
 /// [`Iterator`]: ../iter/trait.IntoIterator.html
 /// [slicing index]: ../slice/trait.SliceIndex.html
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct RangeFull;

 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Debug for RangeFull {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "..")
     }
 }

 /// A (half-open) range bounded inclusively below and exclusively above
 /// (`start..end`).
 ///
 /// The `Range` `start..end` contains all values with `x >= start` and
 /// `x < end`.  It is empty unless `start < end`.
 ///
 /// # Examples
 ///
 /// ```
 /// assert_eq!((3..5), std::ops::Range { start: 3, end: 5 });
 /// assert_eq!(3 + 4 + 5, (3..6).sum());
 ///
 /// let arr = ['a', 'b', 'c', 'd'];
 /// assert_eq!(arr[ .. ], ['a', 'b', 'c', 'd']);
 /// assert_eq!(arr[ ..3], ['a', 'b', 'c',    ]);
 /// assert_eq!(arr[1.. ], [     'b', 'c', 'd']);
 /// assert_eq!(arr[1..3], [     'b', 'c'     ]);  // Range
 /// ```
 #[derive(Clone, PartialEq, Eq, Hash)]  // not Copy -- see #27186
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Range<Idx> {
     /// The lower bound of the range (inclusive).
     #[stable(feature = "rust1", since = "1.0.0")]
     pub start: Idx,
     /// The upper bound of the range (exclusive).
     #[stable(feature = "rust1", since = "1.0.0")]
     pub end: Idx,
 }

 #[stable(feature = "rust1", since = "1.0.0")]
 impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "{:?}..{:?}", self.start, self.end)
     }
 }

 impl<Idx: PartialOrd<Idx>> Range<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(range_contains)]
     ///
     /// assert!(!(3..5).contains(2));
     /// assert!( (3..5).contains(3));
     /// assert!( (3..5).contains(4));
     /// assert!(!(3..5).contains(5));
     ///
     /// assert!(!(3..3).contains(3));
     /// assert!(!(3..2).contains(3));
     /// ```
     #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
     pub fn contains(&self, item: Idx) -> bool {
         (self.start <= item) && (item < self.end)
     }

     /// Returns `true` if the range contains no items.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(range_is_empty)]
     ///
     /// assert!(!(3..5).is_empty());
     /// assert!( (3..3).is_empty());
     /// assert!( (3..2).is_empty());
     /// ```
     ///
     /// The range is empty if either side is incomparable:
     ///
     /// ```
     /// #![feature(range_is_empty)]
     ///
     /// use std::f32::NAN;
     /// assert!(!(3.0..5.0).is_empty());
     /// assert!( (3.0..NAN).is_empty());
     /// assert!( (NAN..5.0).is_empty());
     /// ```
     #[unstable(feature = "range_is_empty", reason = "recently added", issue = "48111")]
     pub fn is_empty(&self) -> bool {
         !(self.start < self.end)
     }
 }

 /// A range only bounded inclusively below (`start..`).
 ///
 /// The `RangeFrom` `start..` contains all values with `x >= start`.
 ///
 /// *Note*: Currently, no overflow checking is done for the [`Iterator`]
 /// implementation; if you use an integer range and the integer overflows, it
 /// might panic in debug mode or create an endless loop in release mode. **This
 /// overflow behavior might change in the future.**
 ///
 /// # Examples
 ///
 /// ```
 /// assert_eq!((2..), std::ops::RangeFrom { start: 2 });
 /// assert_eq!(2 + 3 + 4, (2..).take(3).sum());
 ///
 /// let arr = [0, 1, 2, 3];
 /// assert_eq!(arr[ .. ], [0,1,2,3]);
 /// assert_eq!(arr[ ..3], [0,1,2  ]);
 /// assert_eq!(arr[1.. ], [  1,2,3]);  // RangeFrom
 /// assert_eq!(arr[1..3], [  1,2  ]);
 /// ```
 ///
 /// [`Iterator`]: ../iter/trait.IntoIterator.html
 #[derive(Clone, PartialEq, Eq, Hash)]  // not Copy -- see #27186
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct RangeFrom<Idx> {
     /// The lower bound of the range (inclusive).
     #[stable(feature = "rust1", since = "1.0.0")]
     pub start: Idx,
 }

 #[stable(feature = "rust1", since = "1.0.0")]
 impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "{:?}..", self.start)
     }
 }

 #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
 impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(range_contains)]
     ///
     /// assert!(!(3..).contains(2));
     /// assert!( (3..).contains(3));
     /// assert!( (3..).contains(1_000_000_000));
     /// ```
     pub fn contains(&self, item: Idx) -> bool {
         (self.start <= item)
     }
 }

 /// A range only bounded exclusively above (`..end`).
 ///
 /// The `RangeTo` `..end` contains all values with `x < end`.
 /// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
 ///
 /// # Examples
 ///
 /// The `..end` syntax is a `RangeTo`:
 ///
 /// ```
 /// assert_eq!((..5), std::ops::RangeTo { end: 5 });
 /// ```
 ///
 /// It does not have an [`IntoIterator`] implementation, so you can't use it in
 /// a `for` loop directly. This won't compile:
 ///
 /// ```compile_fail,E0277
 /// // error[E0277]: the trait bound `std::ops::RangeTo<{integer}>:
 /// // std::iter::Iterator` is not satisfied
 /// for i in ..5 {
 ///     // ...
 /// }
 /// ```
 ///
 /// When used as a [slicing index], `RangeTo` produces a slice of all array
 /// elements before the index indicated by `end`.
 ///
 /// ```
 /// let arr = [0, 1, 2, 3];
 /// assert_eq!(arr[ .. ], [0,1,2,3]);
 /// assert_eq!(arr[ ..3], [0,1,2  ]);  // RangeTo
 /// assert_eq!(arr[1.. ], [  1,2,3]);
 /// assert_eq!(arr[1..3], [  1,2  ]);
 /// ```
 ///
 /// [`IntoIterator`]: ../iter/trait.Iterator.html
 /// [`Iterator`]: ../iter/trait.IntoIterator.html
 /// [slicing index]: ../slice/trait.SliceIndex.html
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct RangeTo<Idx> {
     /// The upper bound of the range (exclusive).
     #[stable(feature = "rust1", since = "1.0.0")]
     pub end: Idx,
 }

 #[stable(feature = "rust1", since = "1.0.0")]
 impl<Idx: fmt::Debug> fmt::Debug for RangeTo<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "..{:?}", self.end)
     }
 }

 #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
 impl<Idx: PartialOrd<Idx>> RangeTo<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(range_contains)]
     ///
     /// assert!( (..5).contains(-1_000_000_000));
     /// assert!( (..5).contains(4));
     /// assert!(!(..5).contains(5));
     /// ```
     pub fn contains(&self, item: Idx) -> bool {
         (item < self.end)
     }
 }

 /// An range bounded inclusively below and above (`start..=end`).
 ///
 /// The `RangeInclusive` `start..=end` contains all values with `x >= start`
 /// and `x <= end`.  It is empty unless `start <= end`.
 ///
 /// This iterator is [fused], but the specific values of `start` and `end` after
 /// iteration has finished are **unspecified** other than that [`.is_empty()`]
 /// will return `true` once no more values will be produced.
 ///
 /// [fused]: ../iter/trait.FusedIterator.html
 /// [`.is_empty()`]: #method.is_empty
 ///
 /// # Examples
 ///
 /// ```
 /// #![feature(inclusive_range_fields)]
 ///
 /// assert_eq!((3..=5), std::ops::RangeInclusive { start: 3, end: 5 });
 /// assert_eq!(3 + 4 + 5, (3..=5).sum());
 ///
 /// let arr = [0, 1, 2, 3];
 /// assert_eq!(arr[ ..=2], [0,1,2  ]);
 /// assert_eq!(arr[1..=2], [  1,2  ]);  // RangeInclusive
 /// ```
 #[derive(Clone, PartialEq, Eq, Hash)]  // not Copy -- see #27186
 #[stable(feature = "inclusive_range", since = "1.26.0")]
 pub struct RangeInclusive<Idx> {
     /// The lower bound of the range (inclusive).
     #[unstable(feature = "inclusive_range_fields", issue = "49022")]
     pub start: Idx,
     /// The upper bound of the range (inclusive).
     #[unstable(feature = "inclusive_range_fields", issue = "49022")]
     pub end: Idx,
 }

 #[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 {
         write!(fmt, "{:?}..={:?}", self.start, self.end)
     }
 }

 impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(range_contains)]
     ///
     /// assert!(!(3..=5).contains(2));
     /// assert!( (3..=5).contains(3));
     /// assert!( (3..=5).contains(4));
     /// assert!( (3..=5).contains(5));
     /// assert!(!(3..=5).contains(6));
     ///
     /// assert!( (3..=3).contains(3));
     /// assert!(!(3..=2).contains(3));
     /// ```
     #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
     pub fn contains(&self, item: Idx) -> bool {
         self.start <= item && item <= self.end
     }

     /// Returns `true` if the range contains no items.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(range_is_empty)]
     ///
     /// assert!(!(3..=5).is_empty());
     /// assert!(!(3..=3).is_empty());
     /// assert!( (3..=2).is_empty());
     /// ```
     ///
     /// The range is empty if either side is incomparable:
     ///
     /// ```
     /// #![feature(range_is_empty)]
     ///
     /// use std::f32::NAN;
     /// assert!(!(3.0..=5.0).is_empty());
     /// assert!( (3.0..=NAN).is_empty());
     /// assert!( (NAN..=5.0).is_empty());
     /// ```
     ///
     /// This method returns `true` after iteration has finished:
     ///
     /// ```
     /// #![feature(range_is_empty)]
     ///
     /// let mut r = 3..=5;
     /// for _ in r.by_ref() {}
     /// // Precise field values are unspecified here
     /// assert!(r.is_empty());
     /// ```
     #[unstable(feature = "range_is_empty", reason = "recently added", issue = "48111")]
     pub fn is_empty(&self) -> bool {
         !(self.start <= self.end)
     }
 }

 /// A range only bounded inclusively above (`..=end`).
 ///
 /// The `RangeToInclusive` `..=end` contains all values with `x <= end`.
 /// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
 ///
 /// # Examples
 ///
 /// The `..=end` syntax is a `RangeToInclusive`:
 ///
 /// ```
 /// assert_eq!((..=5), std::ops::RangeToInclusive{ end: 5 });
 /// ```
 ///
 /// It does not have an [`IntoIterator`] implementation, so you can't use it in a
 /// `for` loop directly. This won't compile:
 ///
 /// ```compile_fail,E0277
 /// // error[E0277]: the trait bound `std::ops::RangeToInclusive<{integer}>:
 /// // std::iter::Iterator` is not satisfied
 /// for i in ..=5 {
 ///     // ...
 /// }
 /// ```
 ///
 /// When used as a [slicing index], `RangeToInclusive` produces a slice of all
 /// array elements up to and including the index indicated by `end`.
 ///
 /// ```
 /// let arr = [0, 1, 2, 3];
 /// assert_eq!(arr[ ..=2], [0,1,2  ]);  // RangeToInclusive
 /// assert_eq!(arr[1..=2], [  1,2  ]);
 /// ```
 ///
 /// [`IntoIterator`]: ../iter/trait.Iterator.html
 /// [`Iterator`]: ../iter/trait.IntoIterator.html
 /// [slicing index]: ../slice/trait.SliceIndex.html
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
 #[stable(feature = "inclusive_range", since = "1.26.0")]
 pub struct RangeToInclusive<Idx> {
     /// The upper bound of the range (inclusive)
     #[stable(feature = "inclusive_range", since = "1.26.0")]
     pub end: Idx,
 }

 #[stable(feature = "inclusive_range", since = "1.26.0")]
 impl<Idx: fmt::Debug> fmt::Debug for RangeToInclusive<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "..={:?}", self.end)
     }
 }

 #[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
 impl<Idx: PartialOrd<Idx>> RangeToInclusive<Idx> {
     /// Returns `true` if `item` is contained in the range.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(range_contains)]
     ///
     /// assert!( (..=5).contains(-1_000_000_000));
     /// assert!( (..=5).contains(5));
     /// assert!(!(..=5).contains(6));
     /// ```
     pub fn contains(&self, item: Idx) -> bool {
         (item <= self.end)
     }
 }

 // RangeToInclusive<Idx> cannot impl From<RangeTo<Idx>>
 // because underflow would be possible with (..0).into()

 /// An endpoint of a range of keys.
 ///
 /// # Examples
 ///
 /// `Bound`s are range endpoints:
 ///
 /// ```
 /// #![feature(collections_range)]
 ///
 /// use std::ops::Bound::*;
 /// use std::ops::RangeBounds;
 ///
 /// assert_eq!((..100).start(), Unbounded);
 /// assert_eq!((1..12).start(), Included(&1));
 /// assert_eq!((1..12).end(), Excluded(&12));
 /// ```
 ///
 /// Using a tuple of `Bound`s as an argument to [`BTreeMap::range`].
 /// Note that in most cases, it's better to use range syntax (`1..5`) instead.
 ///
 /// ```
 /// use std::collections::BTreeMap;
 /// use std::ops::Bound::{Excluded, Included, Unbounded};
 ///
 /// let mut map = BTreeMap::new();
 /// map.insert(3, "a");
 /// map.insert(5, "b");
 /// map.insert(8, "c");
 ///
 /// for (key, value) in map.range((Excluded(3), Included(8))) {
 ///     println!("{}: {}", key, value);
 /// }
 ///
 /// assert_eq!(Some((&3, &"a")), map.range((Unbounded, Included(5))).next());
 /// ```
 ///
 /// [`BTreeMap::range`]: ../../std/collections/btree_map/struct.BTreeMap.html#method.range
 #[stable(feature = "collections_bound", since = "1.17.0")]
 #[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
 pub enum Bound<T> {
     /// An inclusive bound.
     #[stable(feature = "collections_bound", since = "1.17.0")]
     Included(#[stable(feature = "collections_bound", since = "1.17.0")] T),
     /// An exclusive bound.
     #[stable(feature = "collections_bound", since = "1.17.0")]
     Excluded(#[stable(feature = "collections_bound", since = "1.17.0")] T),
     /// An infinite endpoint. Indicates that there is no bound in this direction.
     #[stable(feature = "collections_bound", since = "1.17.0")]
     Unbounded,
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 /// `RangeBounds` is implemented by Rust's built-in range types, produced
 /// by range syntax like `..`, `a..`, `..b` or `c..d`.
 pub trait RangeBounds<T: ?Sized> {
     /// Start index bound.
     ///
     /// Returns the start value as a `Bound`.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(collections_range)]
     ///
     /// # fn main() {
     /// use std::ops::Bound::*;
     /// use std::ops::RangeBounds;
     ///
     /// assert_eq!((..10).start(), Unbounded);
     /// assert_eq!((3..10).start(), Included(&3));
     /// # }
     /// ```
     fn start(&self) -> Bound<&T>;

     /// End index bound.
     ///
     /// Returns the end value as a `Bound`.
     ///
     /// # Examples
     ///
     /// ```
     /// #![feature(collections_range)]
     ///
     /// # fn main() {
     /// use std::ops::Bound::*;
     /// use std::ops::RangeBounds;
     ///
     /// assert_eq!((3..).end(), Unbounded);
     /// assert_eq!((3..10).end(), Excluded(&10));
     /// # }
     /// ```
     fn end(&self) -> Bound<&T>;
 }

 use self::Bound::{Excluded, Included, Unbounded};

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<T: ?Sized> RangeBounds<T> for RangeFull {
     fn start(&self) -> Bound<&T> {
         Unbounded
     }
     fn end(&self) -> Bound<&T> {
         Unbounded
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<T> RangeBounds<T> for RangeFrom<T> {
     fn start(&self) -> Bound<&T> {
         Included(&self.start)
     }
     fn end(&self) -> Bound<&T> {
         Unbounded
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<T> RangeBounds<T> for RangeTo<T> {
     fn start(&self) -> Bound<&T> {
         Unbounded
     }
     fn end(&self) -> Bound<&T> {
         Excluded(&self.end)
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<T> RangeBounds<T> for Range<T> {
     fn start(&self) -> Bound<&T> {
         Included(&self.start)
     }
     fn end(&self) -> Bound<&T> {
         Excluded(&self.end)
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<T> RangeBounds<T> for RangeInclusive<T> {
     fn start(&self) -> Bound<&T> {
         Included(&self.start)
     }
     fn end(&self) -> Bound<&T> {
         Included(&self.end)
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<T> RangeBounds<T> for RangeToInclusive<T> {
     fn start(&self) -> Bound<&T> {
         Unbounded
     }
     fn end(&self) -> Bound<&T> {
         Included(&self.end)
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<T> RangeBounds<T> for (Bound<T>, Bound<T>) {
     fn start(&self) -> Bound<&T> {
         match *self {
             (Included(ref start), _) => Included(start),
             (Excluded(ref start), _) => Excluded(start),
             (Unbounded, _)           => Unbounded,
         }
     }

     fn end(&self) -> Bound<&T> {
         match *self {
             (_, Included(ref end)) => Included(end),
             (_, Excluded(ref end)) => Excluded(end),
             (_, Unbounded)         => Unbounded,
         }
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<'a, T: ?Sized + 'a> RangeBounds<T> for (Bound<&'a T>, Bound<&'a T>) {
     fn start(&self) -> Bound<&T> {
         self.0
     }

     fn end(&self) -> Bound<&T> {
         self.1
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<'a, T> RangeBounds<T> for RangeFrom<&'a T> {
     fn start(&self) -> Bound<&T> {
         Included(self.start)
     }
     fn end(&self) -> Bound<&T> {
         Unbounded
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<'a, T> RangeBounds<T> for RangeTo<&'a T> {
     fn start(&self) -> Bound<&T> {
         Unbounded
     }
     fn end(&self) -> Bound<&T> {
         Excluded(self.end)
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<'a, T> RangeBounds<T> for Range<&'a T> {
     fn start(&self) -> Bound<&T> {
         Included(self.start)
     }
     fn end(&self) -> Bound<&T> {
         Excluded(self.end)
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<'a, T> RangeBounds<T> for RangeInclusive<&'a T> {
     fn start(&self) -> Bound<&T> {
         Included(self.start)
     }
     fn end(&self) -> Bound<&T> {
         Included(self.end)
     }
 }

 #[unstable(feature = "collections_range",
            reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
            issue = "30877")]
 impl<'a, T> RangeBounds<T> for RangeToInclusive<&'a T> {
     fn start(&self) -> Bound<&T> {
         Unbounded
     }
     fn end(&self) -> Bound<&T> {
         Included(self.end)
     }
 }
	// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
	// file at the top-level directory of this distribution and at
	// http://rust-lang.org/COPYRIGHT.
	//
	// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
	// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
	// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
	// option. This file may not be copied, modified, or distributed
	// except according to those terms.

	use fmt;

	/// An unbounded range (`..`).
	///
	/// `RangeFull` is primarily used as a [slicing index], its shorthand is `..`.
	/// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
	///
	/// # Examples
	///
	/// The `..` syntax is a `RangeFull`:
	///
	/// ```
	/// assert_eq!((..), std::ops::RangeFull);
	/// ```
	///
	/// It does not have an [`IntoIterator`] implementation, so you can't use it in
	/// a `for` loop directly. This won't compile:
	///
	/// ```compile_fail,E0277
	/// for i in .. {
	/// // ...
	/// }
	/// ```
	///
	/// Used as a [slicing index], `RangeFull` produces the full array as a slice.
	///
	/// ```
	/// let arr = [0, 1, 2, 3];
	/// assert_eq!(arr[ .. ], [0,1,2,3]); // RangeFull
	/// assert_eq!(arr[ ..3], [0,1,2 ]);
	/// assert_eq!(arr[1.. ], [ 1,2,3]);
	/// assert_eq!(arr[1..3], [ 1,2 ]);
	/// ```
	///
	/// [`IntoIterator`]: ../iter/trait.Iterator.html
	/// [`Iterator`]: ../iter/trait.IntoIterator.html
	/// [slicing index]: ../slice/trait.SliceIndex.html
	#[derive(Copy, Clone, PartialEq, Eq, Hash)]
	#[stable(feature = "rust1", since = "1.0.0")]
	pub struct RangeFull;

	#[stable(feature = "rust1", since = "1.0.0")]
	impl fmt::Debug for RangeFull {
	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
	write!(fmt, "..")
	}
	}

	/// A (half-open) range bounded inclusively below and exclusively above
	/// (`start..end`).
	///
	/// The `Range` `start..end` contains all values with `x >= start` and
	/// `x < end`. It is empty unless `start < end`.
	///
	/// # Examples
	///
	/// ```
	/// assert_eq!((3..5), std::ops::Range { start: 3, end: 5 });
	/// assert_eq!(3 + 4 + 5, (3..6).sum());
	///
	/// let arr = ['a', 'b', 'c', 'd'];
	/// assert_eq!(arr[ .. ], ['a', 'b', 'c', 'd']);
	/// assert_eq!(arr[ ..3], ['a', 'b', 'c', ]);
	/// assert_eq!(arr[1.. ], [ 'b', 'c', 'd']);
	/// assert_eq!(arr[1..3], [ 'b', 'c' ]); // Range
	/// ```
	#[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186
	#[stable(feature = "rust1", since = "1.0.0")]
	pub struct Range<Idx> {
	/// The lower bound of the range (inclusive).
	#[stable(feature = "rust1", since = "1.0.0")]
	pub start: Idx,
	/// The upper bound of the range (exclusive).
	#[stable(feature = "rust1", since = "1.0.0")]
	pub end: Idx,
	}

	#[stable(feature = "rust1", since = "1.0.0")]
	impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> {
	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
	write!(fmt, "{:?}..{:?}", self.start, self.end)
	}
	}

	impl<Idx: PartialOrd<Idx>> Range<Idx> {
	/// Returns `true` if `item` is contained in the range.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(range_contains)]
	///
	/// assert!(!(3..5).contains(2));
	/// assert!( (3..5).contains(3));
	/// assert!( (3..5).contains(4));
	/// assert!(!(3..5).contains(5));
	///
	/// assert!(!(3..3).contains(3));
	/// assert!(!(3..2).contains(3));
	/// ```
	#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
	pub fn contains(&self, item: Idx) -> bool {
	(self.start <= item) && (item < self.end)
	}

	/// Returns `true` if the range contains no items.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(range_is_empty)]
	///
	/// assert!(!(3..5).is_empty());
	/// assert!( (3..3).is_empty());
	/// assert!( (3..2).is_empty());
	/// ```
	///
	/// The range is empty if either side is incomparable:
	///
	/// ```
	/// #![feature(range_is_empty)]
	///
	/// use std::f32::NAN;
	/// assert!(!(3.0..5.0).is_empty());
	/// assert!( (3.0..NAN).is_empty());
	/// assert!( (NAN..5.0).is_empty());
	/// ```
	#[unstable(feature = "range_is_empty", reason = "recently added", issue = "48111")]
	pub fn is_empty(&self) -> bool {
	!(self.start < self.end)
	}
	}

	/// A range only bounded inclusively below (`start..`).
	///
	/// The `RangeFrom` `start..` contains all values with `x >= start`.
	///
	/// Note: Currently, no overflow checking is done for the [`Iterator`]
	/// implementation; if you use an integer range and the integer overflows, it
	/// might panic in debug mode or create an endless loop in release mode. **This
	/// overflow behavior might change in the future.**
	///
	/// # Examples
	///
	/// ```
	/// assert_eq!((2..), std::ops::RangeFrom { start: 2 });
	/// assert_eq!(2 + 3 + 4, (2..).take(3).sum());
	///
	/// let arr = [0, 1, 2, 3];
	/// assert_eq!(arr[ .. ], [0,1,2,3]);
	/// assert_eq!(arr[ ..3], [0,1,2 ]);
	/// assert_eq!(arr[1.. ], [ 1,2,3]); // RangeFrom
	/// assert_eq!(arr[1..3], [ 1,2 ]);
	/// ```
	///
	/// [`Iterator`]: ../iter/trait.IntoIterator.html
	#[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186
	#[stable(feature = "rust1", since = "1.0.0")]
	pub struct RangeFrom<Idx> {
	/// The lower bound of the range (inclusive).
	#[stable(feature = "rust1", since = "1.0.0")]
	pub start: Idx,
	}

	#[stable(feature = "rust1", since = "1.0.0")]
	impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> {
	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
	write!(fmt, "{:?}..", self.start)
	}
	}

	#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
	impl<Idx: PartialOrd<Idx>> RangeFrom<Idx> {
	/// Returns `true` if `item` is contained in the range.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(range_contains)]
	///
	/// assert!(!(3..).contains(2));
	/// assert!( (3..).contains(3));
	/// assert!( (3..).contains(1_000_000_000));
	/// ```
	pub fn contains(&self, item: Idx) -> bool {
	(self.start <= item)
	}
	}

	/// A range only bounded exclusively above (`..end`).
	///
	/// The `RangeTo` `..end` contains all values with `x < end`.
	/// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
	///
	/// # Examples
	///
	/// The `..end` syntax is a `RangeTo`:
	///
	/// ```
	/// assert_eq!((..5), std::ops::RangeTo { end: 5 });
	/// ```
	///
	/// It does not have an [`IntoIterator`] implementation, so you can't use it in
	/// a `for` loop directly. This won't compile:
	///
	/// ```compile_fail,E0277
	/// // error[E0277]: the trait bound `std::ops::RangeTo<{integer}>:
	/// // std::iter::Iterator` is not satisfied
	/// for i in ..5 {
	/// // ...
	/// }
	/// ```
	///
	/// When used as a [slicing index], `RangeTo` produces a slice of all array
	/// elements before the index indicated by `end`.
	///
	/// ```
	/// let arr = [0, 1, 2, 3];
	/// assert_eq!(arr[ .. ], [0,1,2,3]);
	/// assert_eq!(arr[ ..3], [0,1,2 ]); // RangeTo
	/// assert_eq!(arr[1.. ], [ 1,2,3]);
	/// assert_eq!(arr[1..3], [ 1,2 ]);
	/// ```
	///
	/// [`IntoIterator`]: ../iter/trait.Iterator.html
	/// [`Iterator`]: ../iter/trait.IntoIterator.html
	/// [slicing index]: ../slice/trait.SliceIndex.html
	#[derive(Copy, Clone, PartialEq, Eq, Hash)]
	#[stable(feature = "rust1", since = "1.0.0")]
	pub struct RangeTo<Idx> {
	/// The upper bound of the range (exclusive).
	#[stable(feature = "rust1", since = "1.0.0")]
	pub end: Idx,
	}

	#[stable(feature = "rust1", since = "1.0.0")]
	impl<Idx: fmt::Debug> fmt::Debug for RangeTo<Idx> {
	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
	write!(fmt, "..{:?}", self.end)
	}
	}

	#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
	impl<Idx: PartialOrd<Idx>> RangeTo<Idx> {
	/// Returns `true` if `item` is contained in the range.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(range_contains)]
	///
	/// assert!( (..5).contains(-1_000_000_000));
	/// assert!( (..5).contains(4));
	/// assert!(!(..5).contains(5));
	/// ```
	pub fn contains(&self, item: Idx) -> bool {
	(item < self.end)
	}
	}

	/// An range bounded inclusively below and above (`start..=end`).
	///
	/// The `RangeInclusive` `start..=end` contains all values with `x >= start`
	/// and `x <= end`. It is empty unless `start <= end`.
	///
	/// This iterator is [fused], but the specific values of `start` and `end` after
	/// iteration has finished are unspecified other than that [`.is_empty()`]
	/// will return `true` once no more values will be produced.
	///
	/// [fused]: ../iter/trait.FusedIterator.html
	/// [`.is_empty()`]: #method.is_empty
	///
	/// # Examples
	///
	/// ```
	/// #![feature(inclusive_range_fields)]
	///
	/// assert_eq!((3..=5), std::ops::RangeInclusive { start: 3, end: 5 });
	/// assert_eq!(3 + 4 + 5, (3..=5).sum());
	///
	/// let arr = [0, 1, 2, 3];
	/// assert_eq!(arr[ ..=2], [0,1,2 ]);
	/// assert_eq!(arr[1..=2], [ 1,2 ]); // RangeInclusive
	/// ```
	#[derive(Clone, PartialEq, Eq, Hash)] // not Copy -- see #27186
	#[stable(feature = "inclusive_range", since = "1.26.0")]
	pub struct RangeInclusive<Idx> {
	/// The lower bound of the range (inclusive).
	#[unstable(feature = "inclusive_range_fields", issue = "49022")]
	pub start: Idx,
	/// The upper bound of the range (inclusive).
	#[unstable(feature = "inclusive_range_fields", issue = "49022")]
	pub end: Idx,
	}

	#[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 {
	write!(fmt, "{:?}..={:?}", self.start, self.end)
	}
	}

	impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
	/// Returns `true` if `item` is contained in the range.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(range_contains)]
	///
	/// assert!(!(3..=5).contains(2));
	/// assert!( (3..=5).contains(3));
	/// assert!( (3..=5).contains(4));
	/// assert!( (3..=5).contains(5));
	/// assert!(!(3..=5).contains(6));
	///
	/// assert!( (3..=3).contains(3));
	/// assert!(!(3..=2).contains(3));
	/// ```
	#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
	pub fn contains(&self, item: Idx) -> bool {
	self.start <= item && item <= self.end
	}

	/// Returns `true` if the range contains no items.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(range_is_empty)]
	///
	/// assert!(!(3..=5).is_empty());
	/// assert!(!(3..=3).is_empty());
	/// assert!( (3..=2).is_empty());
	/// ```
	///
	/// The range is empty if either side is incomparable:
	///
	/// ```
	/// #![feature(range_is_empty)]
	///
	/// use std::f32::NAN;
	/// assert!(!(3.0..=5.0).is_empty());
	/// assert!( (3.0..=NAN).is_empty());
	/// assert!( (NAN..=5.0).is_empty());
	/// ```
	///
	/// This method returns `true` after iteration has finished:
	///
	/// ```
	/// #![feature(range_is_empty)]
	///
	/// let mut r = 3..=5;
	/// for _ in r.by_ref() {}
	/// // Precise field values are unspecified here
	/// assert!(r.is_empty());
	/// ```
	#[unstable(feature = "range_is_empty", reason = "recently added", issue = "48111")]
	pub fn is_empty(&self) -> bool {
	!(self.start <= self.end)
	}
	}

	/// A range only bounded inclusively above (`..=end`).
	///
	/// The `RangeToInclusive` `..=end` contains all values with `x <= end`.
	/// It cannot serve as an [`Iterator`] because it doesn't have a starting point.
	///
	/// # Examples
	///
	/// The `..=end` syntax is a `RangeToInclusive`:
	///
	/// ```
	/// assert_eq!((..=5), std::ops::RangeToInclusive{ end: 5 });
	/// ```
	///
	/// It does not have an [`IntoIterator`] implementation, so you can't use it in a
	/// `for` loop directly. This won't compile:
	///
	/// ```compile_fail,E0277
	/// // error[E0277]: the trait bound `std::ops::RangeToInclusive<{integer}>:
	/// // std::iter::Iterator` is not satisfied
	/// for i in ..=5 {
	/// // ...
	/// }
	/// ```
	///
	/// When used as a [slicing index], `RangeToInclusive` produces a slice of all
	/// array elements up to and including the index indicated by `end`.
	///
	/// ```
	/// let arr = [0, 1, 2, 3];
	/// assert_eq!(arr[ ..=2], [0,1,2 ]); // RangeToInclusive
	/// assert_eq!(arr[1..=2], [ 1,2 ]);
	/// ```
	///
	/// [`IntoIterator`]: ../iter/trait.Iterator.html
	/// [`Iterator`]: ../iter/trait.IntoIterator.html
	/// [slicing index]: ../slice/trait.SliceIndex.html
	#[derive(Copy, Clone, PartialEq, Eq, Hash)]
	#[stable(feature = "inclusive_range", since = "1.26.0")]
	pub struct RangeToInclusive<Idx> {
	/// The upper bound of the range (inclusive)
	#[stable(feature = "inclusive_range", since = "1.26.0")]
	pub end: Idx,
	}

	#[stable(feature = "inclusive_range", since = "1.26.0")]
	impl<Idx: fmt::Debug> fmt::Debug for RangeToInclusive<Idx> {
	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
	write!(fmt, "..={:?}", self.end)
	}
	}

	#[unstable(feature = "range_contains", reason = "recently added as per RFC", issue = "32311")]
	impl<Idx: PartialOrd<Idx>> RangeToInclusive<Idx> {
	/// Returns `true` if `item` is contained in the range.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(range_contains)]
	///
	/// assert!( (..=5).contains(-1_000_000_000));
	/// assert!( (..=5).contains(5));
	/// assert!(!(..=5).contains(6));
	/// ```
	pub fn contains(&self, item: Idx) -> bool {
	(item <= self.end)
	}
	}

	// RangeToInclusive<Idx> cannot impl From<RangeTo<Idx>>
	// because underflow would be possible with (..0).into()

	/// An endpoint of a range of keys.
	///
	/// # Examples
	///
	/// `Bound`s are range endpoints:
	///
	/// ```
	/// #![feature(collections_range)]
	///
	/// use std::ops::Bound::*;
	/// use std::ops::RangeBounds;
	///
	/// assert_eq!((..100).start(), Unbounded);
	/// assert_eq!((1..12).start(), Included(&1));
	/// assert_eq!((1..12).end(), Excluded(&12));
	/// ```
	///
	/// Using a tuple of `Bound`s as an argument to [`BTreeMap::range`].
	/// Note that in most cases, it's better to use range syntax (`1..5`) instead.
	///
	/// ```
	/// use std::collections::BTreeMap;
	/// use std::ops::Bound::{Excluded, Included, Unbounded};
	///
	/// let mut map = BTreeMap::new();
	/// map.insert(3, "a");
	/// map.insert(5, "b");
	/// map.insert(8, "c");
	///
	/// for (key, value) in map.range((Excluded(3), Included(8))) {
	/// println!("{}: {}", key, value);
	/// }
	///
	/// assert_eq!(Some((&3, &"a")), map.range((Unbounded, Included(5))).next());
	/// ```
	///
	/// [`BTreeMap::range`]: ../../std/collections/btree_map/struct.BTreeMap.html#method.range
	#[stable(feature = "collections_bound", since = "1.17.0")]
	#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
	pub enum Bound<T> {
	/// An inclusive bound.
	#[stable(feature = "collections_bound", since = "1.17.0")]
	Included(#[stable(feature = "collections_bound", since = "1.17.0")] T),
	/// An exclusive bound.
	#[stable(feature = "collections_bound", since = "1.17.0")]
	Excluded(#[stable(feature = "collections_bound", since = "1.17.0")] T),
	/// An infinite endpoint. Indicates that there is no bound in this direction.
	#[stable(feature = "collections_bound", since = "1.17.0")]
	Unbounded,
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	/// `RangeBounds` is implemented by Rust's built-in range types, produced
	/// by range syntax like `..`, `a..`, `..b` or `c..d`.
	pub trait RangeBounds<T: ?Sized> {
	/// Start index bound.
	///
	/// Returns the start value as a `Bound`.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(collections_range)]
	///
	/// # fn main() {
	/// use std::ops::Bound::*;
	/// use std::ops::RangeBounds;
	///
	/// assert_eq!((..10).start(), Unbounded);
	/// assert_eq!((3..10).start(), Included(&3));
	/// # }
	/// ```
	fn start(&self) -> Bound<&T>;

	/// End index bound.
	///
	/// Returns the end value as a `Bound`.
	///
	/// # Examples
	///
	/// ```
	/// #![feature(collections_range)]
	///
	/// # fn main() {
	/// use std::ops::Bound::*;
	/// use std::ops::RangeBounds;
	///
	/// assert_eq!((3..).end(), Unbounded);
	/// assert_eq!((3..10).end(), Excluded(&10));
	/// # }
	/// ```
	fn end(&self) -> Bound<&T>;
	}

	use self::Bound::{Excluded, Included, Unbounded};

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<T: ?Sized> RangeBounds<T> for RangeFull {
	fn start(&self) -> Bound<&T> {
	Unbounded
	}
	fn end(&self) -> Bound<&T> {
	Unbounded
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<T> RangeBounds<T> for RangeFrom<T> {
	fn start(&self) -> Bound<&T> {
	Included(&self.start)
	}
	fn end(&self) -> Bound<&T> {
	Unbounded
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<T> RangeBounds<T> for RangeTo<T> {
	fn start(&self) -> Bound<&T> {
	Unbounded
	}
	fn end(&self) -> Bound<&T> {
	Excluded(&self.end)
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<T> RangeBounds<T> for Range<T> {
	fn start(&self) -> Bound<&T> {
	Included(&self.start)
	}
	fn end(&self) -> Bound<&T> {
	Excluded(&self.end)
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<T> RangeBounds<T> for RangeInclusive<T> {
	fn start(&self) -> Bound<&T> {
	Included(&self.start)
	}
	fn end(&self) -> Bound<&T> {
	Included(&self.end)
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<T> RangeBounds<T> for RangeToInclusive<T> {
	fn start(&self) -> Bound<&T> {
	Unbounded
	}
	fn end(&self) -> Bound<&T> {
	Included(&self.end)
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<T> RangeBounds<T> for (Bound<T>, Bound<T>) {
	fn start(&self) -> Bound<&T> {
	match *self {
	(Included(ref start), _) => Included(start),
	(Excluded(ref start), _) => Excluded(start),
	(Unbounded, _) => Unbounded,
	}
	}

	fn end(&self) -> Bound<&T> {
	match *self {
	(_, Included(ref end)) => Included(end),
	(_, Excluded(ref end)) => Excluded(end),
	(_, Unbounded) => Unbounded,
	}
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<'a, T: ?Sized + 'a> RangeBounds<T> for (Bound<&'a T>, Bound<&'a T>) {
	fn start(&self) -> Bound<&T> {
	self.0
	}

	fn end(&self) -> Bound<&T> {
	self.1
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<'a, T> RangeBounds<T> for RangeFrom<&'a T> {
	fn start(&self) -> Bound<&T> {
	Included(self.start)
	}
	fn end(&self) -> Bound<&T> {
	Unbounded
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<'a, T> RangeBounds<T> for RangeTo<&'a T> {
	fn start(&self) -> Bound<&T> {
	Unbounded
	}
	fn end(&self) -> Bound<&T> {
	Excluded(self.end)
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<'a, T> RangeBounds<T> for Range<&'a T> {
	fn start(&self) -> Bound<&T> {
	Included(self.start)
	}
	fn end(&self) -> Bound<&T> {
	Excluded(self.end)
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<'a, T> RangeBounds<T> for RangeInclusive<&'a T> {
	fn start(&self) -> Bound<&T> {
	Included(self.start)
	}
	fn end(&self) -> Bound<&T> {
	Included(self.end)
	}
	}

	#[unstable(feature = "collections_range",
	reason = "might be replaced with `Into<_>` and a type containing two `Bound` values",
	issue = "30877")]
	impl<'a, T> RangeBounds<T> for RangeToInclusive<&'a T> {
	fn start(&self) -> Bound<&T> {
	Unbounded
	}
	fn end(&self) -> Bound<&T> {
	Included(self.end)
	}
	}