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Constify a few const (Partial)Ord impls

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This commit is contained in:
Deadbeef 2021-12-29 14:07:54 +08:00
parent 35a0617248
commit 9fc5463c18
2 changed files with 50 additions and 19 deletions
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68
library/core/src/cmp.rs
View File

@ -22,6 +22,8 @@
#![stable(feature = "rust1", since = "1.0.0")]
use crate::marker::Destruct;
use self::Ordering::*;
/// Trait for equality comparisons which are [partial equivalence
@ -603,7 +605,8 @@ impl Ordering {
pub struct Reverse<T>(#[stable(feature = "reverse_cmp_key", since = "1.19.0")] pub T);
#[stable(feature = "reverse_cmp_key", since = "1.19.0")]
impl<T: PartialOrd> PartialOrd for Reverse<T> {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl<T: ~const PartialOrd> const PartialOrd for Reverse<T> {
#[inline]
fn partial_cmp(&self, other: &Reverse<T>) -> Option<Ordering> {
other.0.partial_cmp(&self.0)
@ -761,6 +764,7 @@ impl<T: Clone> Clone for Reverse<T> {
#[doc(alias = ">=")]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_diagnostic_item = "Ord"]
#[const_trait]
pub trait Ord: Eq + PartialOrd<Self> {
/// This method returns an [`Ordering`] between `self` and `other`.
///
@ -796,8 +800,12 @@ pub trait Ord: Eq + PartialOrd<Self> {
fn max(self, other: Self) -> Self
where
Self: Sized,
Self: ~const Destruct,
{
max_by(self, other, Ord::cmp)
match self.cmp(&other) {
Ordering::Less | Ordering::Equal => other,
Ordering::Greater => self,
}
}
/// Compares and returns the minimum of two values.
@ -816,8 +824,12 @@ pub trait Ord: Eq + PartialOrd<Self> {
fn min(self, other: Self) -> Self
where
Self: Sized,
Self: ~const Destruct,
{
min_by(self, other, Ord::cmp)
match self.cmp(&other) {
Ordering::Less | Ordering::Equal => self,
Ordering::Greater => other,
}
}
/// Restrict a value to a certain interval.
@ -841,6 +853,8 @@ pub trait Ord: Eq + PartialOrd<Self> {
fn clamp(self, min: Self, max: Self) -> Self
where
Self: Sized,
Self: ~const Destruct,
Self: ~const PartialOrd,
{
assert!(min <= max);
if self < min {
@ -862,7 +876,8 @@ pub macro Ord($item:item) {
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Ord for Ordering {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const Ord for Ordering {
#[inline]
fn cmp(&self, other: &Ordering) -> Ordering {
(*self as i32).cmp(&(*other as i32))
@ -870,7 +885,8 @@ impl Ord for Ordering {
}
#[stable(feature = "rust1", since = "1.0.0")]
impl PartialOrd for Ordering {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialOrd for Ordering {
#[inline]
fn partial_cmp(&self, other: &Ordering) -> Option<Ordering> {
(*self as i32).partial_cmp(&(*other as i32))
@ -1187,8 +1203,9 @@ pub macro PartialOrd($item:item) {
#[inline]
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
#[cfg_attr(not(test), rustc_diagnostic_item = "cmp_min")]
pub fn min<T: Ord>(v1: T, v2: T) -> T {
pub const fn min<T: ~const Ord + ~const Destruct>(v1: T, v2: T) -> T {
v1.min(v2)
}
@ -1250,8 +1267,9 @@ pub fn min_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T {
#[inline]
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
#[cfg_attr(not(test), rustc_diagnostic_item = "cmp_max")]
pub fn max<T: Ord>(v1: T, v2: T) -> T {
pub const fn max<T: ~const Ord + ~const Destruct>(v1: T, v2: T) -> T {
v1.max(v2)
}
@ -1304,7 +1322,8 @@ mod impls {
macro_rules! partial_eq_impl {
($($t:ty)*) => ($(
#[stable(feature = "rust1", since = "1.0.0")]
impl PartialEq for $t {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialEq for $t {
#[inline]
fn eq(&self, other: &$t) -> bool { (*self) == (*other) }
#[inline]
@ -1314,7 +1333,8 @@ mod impls {
}
#[stable(feature = "rust1", since = "1.0.0")]
impl PartialEq for () {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialEq for () {
#[inline]
fn eq(&self, _other: &()) -> bool {
true
@ -1341,7 +1361,8 @@ mod impls {
macro_rules! partial_ord_impl {
($($t:ty)*) => ($(
#[stable(feature = "rust1", since = "1.0.0")]
impl PartialOrd for $t {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialOrd for $t {
#[inline]
fn partial_cmp(&self, other: &$t) -> Option<Ordering> {
match (*self <= *other, *self >= *other) {
@ -1364,7 +1385,8 @@ mod impls {
}
#[stable(feature = "rust1", since = "1.0.0")]
impl PartialOrd for () {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialOrd for () {
#[inline]
fn partial_cmp(&self, _: &()) -> Option<Ordering> {
Some(Equal)
@ -1372,7 +1394,8 @@ mod impls {
}
#[stable(feature = "rust1", since = "1.0.0")]
impl PartialOrd for bool {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialOrd for bool {
#[inline]
fn partial_cmp(&self, other: &bool) -> Option<Ordering> {
Some(self.cmp(other))
@ -1384,7 +1407,8 @@ mod impls {
macro_rules! ord_impl {
($($t:ty)*) => ($(
#[stable(feature = "rust1", since = "1.0.0")]
impl PartialOrd for $t {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialOrd for $t {
#[inline]
fn partial_cmp(&self, other: &$t) -> Option<Ordering> {
Some(self.cmp(other))
@ -1400,7 +1424,8 @@ mod impls {
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Ord for $t {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const Ord for $t {
#[inline]
fn cmp(&self, other: &$t) -> Ordering {
// The order here is important to generate more optimal assembly.
@ -1414,7 +1439,8 @@ mod impls {
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Ord for () {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const Ord for () {
#[inline]
fn cmp(&self, _other: &()) -> Ordering {
Equal
@ -1422,7 +1448,8 @@ mod impls {
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Ord for bool {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const Ord for bool {
#[inline]
fn cmp(&self, other: &bool) -> Ordering {
// Casting to i8's and converting the difference to an Ordering generates
@ -1441,7 +1468,8 @@ mod impls {
ord_impl! { char usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
#[unstable(feature = "never_type", issue = "35121")]
impl PartialEq for ! {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialEq for ! {
fn eq(&self, _: &!) -> bool {
*self
}
@ -1451,14 +1479,16 @@ mod impls {
impl Eq for ! {}
#[unstable(feature = "never_type", issue = "35121")]
impl PartialOrd for ! {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const PartialOrd for ! {
fn partial_cmp(&self, _: &!) -> Option<Ordering> {
*self
}
}
#[unstable(feature = "never_type", issue = "35121")]
impl Ord for ! {
#[rustc_const_unstable(feature = "const_cmp", issue = "none")]
impl const Ord for ! {
fn cmp(&self, _: &!) -> Ordering {
*self
}

1
library/core/src/lib.rs
View File

@ -105,6 +105,7 @@
#![feature(const_cell_into_inner)]
#![feature(const_char_convert)]
#![feature(const_clone)]
#![feature(const_cmp)]
#![feature(const_discriminant)]
#![feature(const_eval_select)]
#![feature(const_float_bits_conv)]