diff options
Diffstat (limited to 'library/core/src/slice/cmp.rs')
| -rw-r--r-- | library/core/src/slice/cmp.rs | 43 |
1 files changed, 31 insertions, 12 deletions
diff --git a/library/core/src/slice/cmp.rs b/library/core/src/slice/cmp.rs index 0d801306984..103630aba0f 100644 --- a/library/core/src/slice/cmp.rs +++ b/library/core/src/slice/cmp.rs @@ -23,7 +23,8 @@ where } #[stable(feature = "rust1", since = "1.0.0")] -impl<T: Eq> Eq for [T] {} +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +impl<T: [const] Eq> const Eq for [T] {} /// Implements comparison of slices [lexicographically](Ord#lexicographical-comparison). #[stable(feature = "rust1", since = "1.0.0")] @@ -34,7 +35,7 @@ impl<T: Ord> Ord for [T] { } #[inline] -fn as_underlying(x: ControlFlow<bool>) -> u8 { +const fn as_underlying(x: ControlFlow<bool>) -> u8 { // SAFETY: This will only compile if `bool` and `ControlFlow<bool>` have the same // size (which isn't guaranteed but this is libcore). Because they have the same // size, it's a niched implementation, which in one byte means there can't be @@ -154,12 +155,16 @@ where } #[doc(hidden)] +#[const_trait] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] // intermediate trait for specialization of slice's PartialOrd trait SlicePartialOrd: Sized { fn partial_compare(left: &[Self], right: &[Self]) -> Option<Ordering>; } #[doc(hidden)] +#[const_trait] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] // intermediate trait for specialization of slice's PartialOrd chaining methods trait SliceChain: Sized { fn chaining_lt(left: &[Self], right: &[Self]) -> ControlFlow<bool>; @@ -231,14 +236,17 @@ where } */ -impl<A: AlwaysApplicableOrd> SlicePartialOrd for A { +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +impl<A: [const] AlwaysApplicableOrd> const SlicePartialOrd for A { fn partial_compare(left: &[A], right: &[A]) -> Option<Ordering> { Some(SliceOrd::compare(left, right)) } } #[rustc_specialization_trait] -trait AlwaysApplicableOrd: SliceOrd + Ord {} +#[const_trait] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +trait AlwaysApplicableOrd: [const] SliceOrd + [const] Ord {} macro_rules! always_applicable_ord { ($([$($p:tt)*] $t:ty,)*) => { @@ -257,6 +265,8 @@ always_applicable_ord! { } #[doc(hidden)] +#[const_trait] +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] // intermediate trait for specialization of slice's Ord trait SliceOrd: Sized { fn compare(left: &[Self], right: &[Self]) -> Ordering; @@ -282,17 +292,24 @@ impl<A: Ord> SliceOrd for A { /// * For every `x` and `y` of this type, `Ord(x, y)` must return the same /// value as `Ord::cmp(transmute::<_, u8>(x), transmute::<_, u8>(y))`. #[rustc_specialization_trait] -unsafe trait UnsignedBytewiseOrd: Ord {} +#[const_trait] +unsafe trait UnsignedBytewiseOrd: [const] Ord {} -unsafe impl UnsignedBytewiseOrd for bool {} -unsafe impl UnsignedBytewiseOrd for u8 {} -unsafe impl UnsignedBytewiseOrd for NonZero<u8> {} -unsafe impl UnsignedBytewiseOrd for Option<NonZero<u8>> {} -unsafe impl UnsignedBytewiseOrd for ascii::Char {} +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +unsafe impl const UnsignedBytewiseOrd for bool {} +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +unsafe impl const UnsignedBytewiseOrd for u8 {} +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +unsafe impl const UnsignedBytewiseOrd for NonZero<u8> {} +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +unsafe impl const UnsignedBytewiseOrd for Option<NonZero<u8>> {} +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +unsafe impl const UnsignedBytewiseOrd for ascii::Char {} // `compare_bytes` compares a sequence of unsigned bytes lexicographically, so // use it if the requirements for `UnsignedBytewiseOrd` are fulfilled. -impl<A: Ord + UnsignedBytewiseOrd> SliceOrd for A { +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +impl<A: [const] Ord + [const] UnsignedBytewiseOrd> const SliceOrd for A { #[inline] fn compare(left: &[Self], right: &[Self]) -> Ordering { // Since the length of a slice is always less than or equal to @@ -317,7 +334,9 @@ impl<A: Ord + UnsignedBytewiseOrd> SliceOrd for A { } // Don't generate our own chaining loops for `memcmp`-able things either. -impl<A: PartialOrd + UnsignedBytewiseOrd> SliceChain for A { + +#[rustc_const_unstable(feature = "const_cmp", issue = "143800")] +impl<A: [const] PartialOrd + [const] UnsignedBytewiseOrd> const SliceChain for A { #[inline] fn chaining_lt(left: &[Self], right: &[Self]) -> ControlFlow<bool> { match SliceOrd::compare(left, right) { |