constify some methods using `SliceIndex`

1 files changed, 4 insertions, 2 deletions

diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs
index fba3436496e..bb0106b9fd9 100644
--- a/library/core/src/str/mod.rs
+++ b/library/core/src/str/mod.rs
@@ -589,8 +589,9 @@ impl str {
     /// assert!(v.get(..42).is_none());
     /// ```
     #[stable(feature = "str_checked_slicing", since = "1.20.0")]
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
     #[inline]
-    pub fn get<I: SliceIndex<str>>(&self, i: I) -> Option<&I::Output> {
+    pub const fn get<I: ~const SliceIndex<str>>(&self, i: I) -> Option<&I::Output> {
         i.get(self)
     }
 
@@ -621,8 +622,9 @@ impl str {
     /// assert_eq!("HEllo", v);
     /// ```
     #[stable(feature = "str_checked_slicing", since = "1.20.0")]
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
     #[inline]
-    pub fn get_mut<I: SliceIndex<str>>(&mut self, i: I) -> Option<&mut I::Output> {
+    pub const fn get_mut<I: ~const SliceIndex<str>>(&mut self, i: I) -> Option<&mut I::Output> {
         i.get_mut(self)
     }