Make Borrow and BorrowMut impls const

rust-lang · Dec 4, 2021 · 8f68bdc · 8f68bdc
1 parent 68a698b
commit 8f68bdc
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Showing 2 changed files with 14 additions and 7 deletions.
diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
@@ -149,14 +149,16 @@ impl<T, const N: usize> AsMut<[T]> for [T; N] {
 }
 
 #[stable(feature = "array_borrow", since = "1.4.0")]
-impl<T, const N: usize> Borrow<[T]> for [T; N] {
+#[rustc_const_unstable(feature = "const_borrow", issue = "91522")]
+impl<T, const N: usize> const Borrow<[T]> for [T; N] {
     fn borrow(&self) -> &[T] {
         self
     }
 }
 
 #[stable(feature = "array_borrow", since = "1.4.0")]
-impl<T, const N: usize> BorrowMut<[T]> for [T; N] {
+#[rustc_const_unstable(feature = "const_borrow", issue = "91522")]
+impl<T, const N: usize> const BorrowMut<[T]> for [T; N] {
     fn borrow_mut(&mut self) -> &mut [T] {
         self
     }

diff --git a/library/core/src/borrow.rs b/library/core/src/borrow.rs
@@ -205,36 +205,41 @@ pub trait BorrowMut<Borrowed: ?Sized>: Borrow<Borrowed> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: ?Sized> Borrow<T> for T {
+#[rustc_const_unstable(feature = "const_borrow", issue = "91522")]
+impl<T: ?Sized> const Borrow<T> for T {
     #[rustc_diagnostic_item = "noop_method_borrow"]
     fn borrow(&self) -> &T {
         self
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: ?Sized> BorrowMut<T> for T {
+#[rustc_const_unstable(feature = "const_borrow", issue = "91522")]
+impl<T: ?Sized> const BorrowMut<T> for T {
     fn borrow_mut(&mut self) -> &mut T {
         self
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: ?Sized> Borrow<T> for &T {
+#[rustc_const_unstable(feature = "const_borrow", issue = "91522")]
+impl<T: ?Sized> const Borrow<T> for &T {
     fn borrow(&self) -> &T {
         &**self
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: ?Sized> Borrow<T> for &mut T {
+#[rustc_const_unstable(feature = "const_borrow", issue = "91522")]
+impl<T: ?Sized> const Borrow<T> for &mut T {
     fn borrow(&self) -> &T {
         &**self
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: ?Sized> BorrowMut<T> for &mut T {
+#[rustc_const_unstable(feature = "const_borrow", issue = "91522")]
+impl<T: ?Sized> const BorrowMut<T> for &mut T {
     fn borrow_mut(&mut self) -> &mut T {
         &mut **self
     }