diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs index 50b8264bac72a..f0fa2e1d2c190 100644 --- a/library/core/src/cmp.rs +++ b/library/core/src/cmp.rs @@ -22,6 +22,7 @@ #![stable(feature = "rust1", since = "1.0.0")] +use crate::const_closure::ConstFnMutClosure; use crate::marker::Destruct; use crate::marker::StructuralPartialEq; @@ -1222,7 +1223,12 @@ pub const fn min(v1: T, v2: T) -> T { #[inline] #[must_use] #[stable(feature = "cmp_min_max_by", since = "1.53.0")] -pub fn min_by Ordering>(v1: T, v2: T, compare: F) -> T { +#[rustc_const_unstable(feature = "const_cmp", issue = "92391")] +pub const fn min_by 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, @@ -1244,8 +1250,24 @@ pub fn min_by 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 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 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 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. @@ -1286,7 +1308,12 @@ pub const fn max(v1: T, v2: T) -> T { #[inline] #[must_use] #[stable(feature = "cmp_min_max_by", since = "1.53.0")] -pub fn max_by Ordering>(v1: T, v2: T, compare: F) -> T { +#[rustc_const_unstable(feature = "const_cmp", issue = "92391")] +pub const fn max_by 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, @@ -1308,8 +1335,24 @@ pub fn max_by 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 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 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 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