Adding upstream version 1.66.0+dfsg1.upstream/1.66.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 80 insertions, 45 deletions

diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs
index 20bb67687..f0fa2e1d2 100644
--- a/library/core/src/cmp.rs
+++ b/library/core/src/cmp.rs
@@ -1,6 +1,6 @@
-//! Functionality for ordering and comparison.
+//! Utilities for comparing and ordering values.
 //!
-//! This module contains various tools for ordering and comparing values. In
+//! This module contains various tools for comparing and ordering values. In
 //! summary:
 //!
 //! * [`Eq`] and [`PartialEq`] are traits that allow you to define total and
@@ -22,7 +22,9 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
+use crate::const_closure::ConstFnMutClosure;
 use crate::marker::Destruct;
+use crate::marker::StructuralPartialEq;
 
 use self::Ordering::*;
 
@@ -38,8 +40,10 @@ use self::Ordering::*;
 ///
 /// Implementations must ensure that `eq` and `ne` are consistent with each other:
 ///
-/// - `a != b` if and only if `!(a == b)`
-///   (ensured by the default implementation).
+/// - `a != b` if and only if `!(a == b)`.
+///
+/// The default implementation of `ne` provides this consistency and is almost
+/// always sufficient. It should not be overridden without very good reason.
 ///
 /// If [`PartialOrd`] or [`Ord`] are also implemented for `Self` and `Rhs`, their methods must also
 /// be consistent with `PartialEq` (see the documentation of those traits for the exact
@@ -201,20 +205,10 @@ use self::Ordering::*;
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(alias = "==")]
 #[doc(alias = "!=")]
-#[cfg_attr(
-    bootstrap,
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} == {Rhs}`"
-    )
-)]
-#[cfg_attr(
-    not(bootstrap),
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} == {Rhs}`",
-        append_const_msg,
-    )
+#[rustc_on_unimplemented(
+    message = "can't compare `{Self}` with `{Rhs}`",
+    label = "no implementation for `{Self} == {Rhs}`",
+    append_const_msg
 )]
 #[const_trait]
 #[rustc_diagnostic_item = "PartialEq"]
@@ -225,7 +219,8 @@ pub trait PartialEq<Rhs: ?Sized = Self> {
     #[stable(feature = "rust1", since = "1.0.0")]
     fn eq(&self, other: &Rhs) -> bool;
 
-    /// This method tests for `!=`.
+    /// This method tests for `!=`. The default implementation is almost always
+    /// sufficient, and should not be overridden without very good reason.
     #[inline]
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -335,7 +330,7 @@ pub struct AssertParamIsEq<T: Eq + ?Sized> {
 /// let result = 2.cmp(&1);
 /// assert_eq!(Ordering::Greater, result);
 /// ```
-#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
+#[derive(Clone, Copy, Eq, Debug, Hash)]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[repr(i8)]
 pub enum Ordering {
@@ -882,6 +877,18 @@ pub macro Ord($item:item) {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
+impl StructuralPartialEq for Ordering {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+impl const PartialEq for Ordering {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        (*self as i32).eq(&(*other as i32))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
 impl const Ord for Ordering {
     #[inline]
@@ -1060,20 +1067,10 @@ impl const PartialOrd for Ordering {
 #[doc(alias = "<")]
 #[doc(alias = "<=")]
 #[doc(alias = ">=")]
-#[cfg_attr(
-    bootstrap,
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
-    )
-)]
-#[cfg_attr(
-    not(bootstrap),
-    rustc_on_unimplemented(
-        message = "can't compare `{Self}` with `{Rhs}`",
-        label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
-        append_const_msg,
-    )
+#[rustc_on_unimplemented(
+    message = "can't compare `{Self}` with `{Rhs}`",
+    label = "no implementation for `{Self} < {Rhs}` and `{Self} > {Rhs}`",
+    append_const_msg
 )]
 #[const_trait]
 #[rustc_diagnostic_item = "PartialOrd"]
@@ -1139,11 +1136,7 @@ pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn le(&self, other: &Rhs) -> bool {
-        // Pattern `Some(Less | Eq)` optimizes worse than negating `None | Some(Greater)`.
-        // FIXME: The root cause was fixed upstream in LLVM with:
-        // https://github.com/llvm/llvm-project/commit/9bad7de9a3fb844f1ca2965f35d0c2a3d1e11775
-        // Revert this workaround once support for LLVM 12 gets dropped.
-        !matches!(self.partial_cmp(other), None | Some(Greater))
+        matches!(self.partial_cmp(other), Some(Less | Equal))
     }
 
     /// This method tests greater than (for `self` and `other`) and is used by the `>` operator.
@@ -1230,7 +1223,12 @@ pub const fn min<T: ~const Ord + ~const Destruct>(v1: T, v2: T) -> T {
 #[inline]
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
-pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+pub const fn min_by<T, F: ~const FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T
+where
+    T: ~const Destruct,
+    F: ~const Destruct,
+{
     match compare(&v1, &v2) {
         Ordering::Less | Ordering::Equal => v1,
         Ordering::Greater => v2,
@@ -1252,8 +1250,24 @@ pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
 #[inline]
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
-pub fn min_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T {
-    min_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2)))
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+pub const fn min_by_key<T, F: ~const FnMut(&T) -> K, K: ~const Ord>(v1: T, v2: T, mut f: F) -> T
+where
+    T: ~const Destruct,
+    F: ~const Destruct,
+    K: ~const Destruct,
+{
+    const fn imp<T, F: ~const FnMut(&T) -> K, K: ~const Ord>(
+        f: &mut F,
+        (v1, v2): (&T, &T),
+    ) -> Ordering
+    where
+        T: ~const Destruct,
+        K: ~const Destruct,
+    {
+        f(v1).cmp(&f(v2))
+    }
+    min_by(v1, v2, ConstFnMutClosure::new(&mut f, imp))
 }
 
 /// Compares and returns the maximum of two values.
@@ -1294,7 +1308,12 @@ pub const fn max<T: ~const Ord + ~const Destruct>(v1: T, v2: T) -> T {
 #[inline]
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
-pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+pub const fn max_by<T, F: ~const FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T
+where
+    T: ~const Destruct,
+    F: ~const Destruct,
+{
     match compare(&v1, &v2) {
         Ordering::Less | Ordering::Equal => v2,
         Ordering::Greater => v1,
@@ -1316,8 +1335,24 @@ pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T {
 #[inline]
 #[must_use]
 #[stable(feature = "cmp_min_max_by", since = "1.53.0")]
-pub fn max_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T {
-    max_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2)))
+#[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+pub const fn max_by_key<T, F: ~const FnMut(&T) -> K, K: ~const Ord>(v1: T, v2: T, mut f: F) -> T
+where
+    T: ~const Destruct,
+    F: ~const Destruct,
+    K: ~const Destruct,
+{
+    const fn imp<T, F: ~const FnMut(&T) -> K, K: ~const Ord>(
+        f: &mut F,
+        (v1, v2): (&T, &T),
+    ) -> Ordering
+    where
+        T: ~const Destruct,
+        K: ~const Destruct,
+    {
+        f(v1).cmp(&f(v2))
+    }
+    max_by(v1, v2, ConstFnMutClosure::new(&mut f, imp))
 }
 
 // Implementation of PartialEq, Eq, PartialOrd and Ord for primitive types