diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index 16356f749c92b..62203e132b70c 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -374,9 +374,10 @@ impl<'a, T, const N: usize> IntoIterator for &'a mut [T; N] {
 }
 
 #[stable(feature = "index_trait_on_arrays", since = "1.50.0")]
-impl<T, I, const N: usize> Index<I> for [T; N]
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T, I, const N: usize> const Index<I> for [T; N]
 where
-    [T]: Index<I>,
+    [T]: ~const Index<I>,
 {
     type Output = <[T] as Index<I>>::Output;
 
@@ -387,9 +388,10 @@ where
 }
 
 #[stable(feature = "index_trait_on_arrays", since = "1.50.0")]
-impl<T, I, const N: usize> IndexMut<I> for [T; N]
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T, I, const N: usize> const IndexMut<I> for [T; N]
 where
-    [T]: IndexMut<I>,
+    [T]: ~const IndexMut<I>,
 {
     #[inline]
     fn index_mut(&mut self, index: I) -> &mut Self::Output {
diff --git a/library/core/src/ops/index.rs b/library/core/src/ops/index.rs
index 8092fa9eb2fc5..d8489e9a94913 100644
--- a/library/core/src/ops/index.rs
+++ b/library/core/src/ops/index.rs
@@ -55,6 +55,8 @@
 #[doc(alias = "]")]
 #[doc(alias = "[")]
 #[doc(alias = "[]")]
+#[const_trait]
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
 pub trait Index<Idx: ?Sized> {
     /// The returned type after indexing.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -165,7 +167,9 @@ see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#ind
 #[doc(alias = "[")]
 #[doc(alias = "]")]
 #[doc(alias = "[]")]
-pub trait IndexMut<Idx: ?Sized>: Index<Idx> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+#[const_trait]
+pub trait IndexMut<Idx: ?Sized>: ~const Index<Idx> {
     /// Performs the mutable indexing (`container[index]`) operation.
     ///
     /// # Panics
diff --git a/library/core/src/ptr/const_ptr.rs b/library/core/src/ptr/const_ptr.rs
index 27b0c6830db61..2ad520b7ead72 100644
--- a/library/core/src/ptr/const_ptr.rs
+++ b/library/core/src/ptr/const_ptr.rs
@@ -1524,10 +1524,11 @@ impl<T> *const [T] {
     /// }
     /// ```
     #[unstable(feature = "slice_ptr_get", issue = "74265")]
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
     #[inline]
-    pub unsafe fn get_unchecked<I>(self, index: I) -> *const I::Output
+    pub const unsafe fn get_unchecked<I>(self, index: I) -> *const I::Output
     where
-        I: SliceIndex<[T]>,
+        I: ~const SliceIndex<[T]>,
     {
         // SAFETY: the caller ensures that `self` is dereferenceable and `index` in-bounds.
         unsafe { index.get_unchecked(self) }
diff --git a/library/core/src/ptr/mut_ptr.rs b/library/core/src/ptr/mut_ptr.rs
index 73efdf0445412..579e2461103d8 100644
--- a/library/core/src/ptr/mut_ptr.rs
+++ b/library/core/src/ptr/mut_ptr.rs
@@ -1881,10 +1881,11 @@ impl<T> *mut [T] {
     /// }
     /// ```
     #[unstable(feature = "slice_ptr_get", issue = "74265")]
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
     #[inline(always)]
-    pub unsafe fn get_unchecked_mut<I>(self, index: I) -> *mut I::Output
+    pub const unsafe fn get_unchecked_mut<I>(self, index: I) -> *mut I::Output
     where
-        I: SliceIndex<[T]>,
+        I: ~const SliceIndex<[T]>,
     {
         // SAFETY: the caller ensures that `self` is dereferenceable and `index` in-bounds.
         unsafe { index.get_unchecked_mut(self) }
diff --git a/library/core/src/ptr/non_null.rs b/library/core/src/ptr/non_null.rs
index c4ca29a367971..62da6567cca75 100644
--- a/library/core/src/ptr/non_null.rs
+++ b/library/core/src/ptr/non_null.rs
@@ -1597,10 +1597,11 @@ impl<T> NonNull<[T]> {
     /// }
     /// ```
     #[unstable(feature = "slice_ptr_get", issue = "74265")]
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
     #[inline]
-    pub unsafe fn get_unchecked_mut<I>(self, index: I) -> NonNull<I::Output>
+    pub const unsafe fn get_unchecked_mut<I>(self, index: I) -> NonNull<I::Output>
     where
-        I: SliceIndex<[T]>,
+        I: ~const SliceIndex<[T]>,
     {
         // SAFETY: the caller ensures that `self` is dereferenceable and `index` in-bounds.
         // As a consequence, the resulting pointer cannot be null.
diff --git a/library/core/src/range.rs b/library/core/src/range.rs
index 2276112a27bb3..5cd7956291ca2 100644
--- a/library/core/src/range.rs
+++ b/library/core/src/range.rs
@@ -186,14 +186,17 @@ impl<T> IntoBounds<T> for Range<T> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-impl<T> From<Range<T>> for legacy::Range<T> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T> const From<Range<T>> for legacy::Range<T> {
     #[inline]
     fn from(value: Range<T>) -> Self {
         Self { start: value.start, end: value.end }
     }
 }
+
 #[unstable(feature = "new_range_api", issue = "125687")]
-impl<T> From<legacy::Range<T>> for Range<T> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T> const From<legacy::Range<T>> for Range<T> {
     #[inline]
     fn from(value: legacy::Range<T>) -> Self {
         Self { start: value.start, end: value.end }
@@ -362,7 +365,8 @@ impl<T> IntoBounds<T> for RangeInclusive<T> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-impl<T> From<RangeInclusive<T>> for legacy::RangeInclusive<T> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T> const From<RangeInclusive<T>> for legacy::RangeInclusive<T> {
     #[inline]
     fn from(value: RangeInclusive<T>) -> Self {
         Self::new(value.start, value.end)
@@ -506,14 +510,16 @@ impl<T> IntoBounds<T> for RangeFrom<T> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-impl<T> From<RangeFrom<T>> for legacy::RangeFrom<T> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T> const From<RangeFrom<T>> for legacy::RangeFrom<T> {
     #[inline]
     fn from(value: RangeFrom<T>) -> Self {
         Self { start: value.start }
     }
 }
 #[unstable(feature = "new_range_api", issue = "125687")]
-impl<T> From<legacy::RangeFrom<T>> for RangeFrom<T> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T> const From<legacy::RangeFrom<T>> for RangeFrom<T> {
     #[inline]
     fn from(value: legacy::RangeFrom<T>) -> Self {
         Self { start: value.start }
diff --git a/library/core/src/slice/index.rs b/library/core/src/slice/index.rs
index f725c3fdd94cc..322b3580eded2 100644
--- a/library/core/src/slice/index.rs
+++ b/library/core/src/slice/index.rs
@@ -6,9 +6,10 @@ use crate::ub_checks::assert_unsafe_precondition;
 use crate::{ops, range};
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, I> ops::Index<I> for [T]
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T, I> const ops::Index<I> for [T]
 where
-    I: SliceIndex<[T]>,
+    I: ~const SliceIndex<[T]>,
 {
     type Output = I::Output;
 
@@ -19,9 +20,10 @@ where
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T, I> ops::IndexMut<I> for [T]
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<T, I> const ops::IndexMut<I> for [T]
 where
-    I: SliceIndex<[T]>,
+    I: ~const SliceIndex<[T]>,
 {
     #[inline(always)]
     fn index_mut(&mut self, index: I) -> &mut I::Output {
@@ -158,6 +160,8 @@ mod private_slice_index {
     message = "the type `{T}` cannot be indexed by `{Self}`",
     label = "slice indices are of type `usize` or ranges of `usize`"
 )]
+#[const_trait]
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
 pub unsafe trait SliceIndex<T: ?Sized>: private_slice_index::Sealed {
     /// The output type returned by methods.
     #[stable(feature = "slice_get_slice", since = "1.28.0")]
@@ -208,7 +212,8 @@ pub unsafe trait SliceIndex<T: ?Sized>: private_slice_index::Sealed {
 
 /// The methods `index` and `index_mut` panic if the index is out of bounds.
 #[stable(feature = "slice_get_slice_impls", since = "1.15.0")]
-unsafe impl<T> SliceIndex<[T]> for usize {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for usize {
     type Output = T;
 
     #[inline]
@@ -278,7 +283,8 @@ unsafe impl<T> SliceIndex<[T]> for usize {
 
 /// Because `IndexRange` guarantees `start <= end`, fewer checks are needed here
 /// than there are for a general `Range<usize>` (which might be `100..3`).
-unsafe impl<T> SliceIndex<[T]> for ops::IndexRange {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for ops::IndexRange {
     type Output = [T];
 
     #[inline]
@@ -354,7 +360,8 @@ unsafe impl<T> SliceIndex<[T]> for ops::IndexRange {
 /// - the start of the range is greater than the end of the range or
 /// - the end of the range is out of bounds.
 #[stable(feature = "slice_get_slice_impls", since = "1.15.0")]
-unsafe impl<T> SliceIndex<[T]> for ops::Range<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for ops::Range<usize> {
     type Output = [T];
 
     #[inline]
@@ -453,7 +460,8 @@ unsafe impl<T> SliceIndex<[T]> for ops::Range<usize> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-unsafe impl<T> SliceIndex<[T]> for range::Range<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for range::Range<usize> {
     type Output = [T];
 
     #[inline]
@@ -491,7 +499,8 @@ unsafe impl<T> SliceIndex<[T]> for range::Range<usize> {
 
 /// The methods `index` and `index_mut` panic if the end of the range is out of bounds.
 #[stable(feature = "slice_get_slice_impls", since = "1.15.0")]
-unsafe impl<T> SliceIndex<[T]> for ops::RangeTo<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for ops::RangeTo<usize> {
     type Output = [T];
 
     #[inline]
@@ -529,7 +538,8 @@ unsafe impl<T> SliceIndex<[T]> for ops::RangeTo<usize> {
 
 /// The methods `index` and `index_mut` panic if the start of the range is out of bounds.
 #[stable(feature = "slice_get_slice_impls", since = "1.15.0")]
-unsafe impl<T> SliceIndex<[T]> for ops::RangeFrom<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for ops::RangeFrom<usize> {
     type Output = [T];
 
     #[inline]
@@ -574,7 +584,8 @@ unsafe impl<T> SliceIndex<[T]> for ops::RangeFrom<usize> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-unsafe impl<T> SliceIndex<[T]> for range::RangeFrom<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for range::RangeFrom<usize> {
     type Output = [T];
 
     #[inline]
@@ -611,7 +622,8 @@ unsafe impl<T> SliceIndex<[T]> for range::RangeFrom<usize> {
 }
 
 #[stable(feature = "slice_get_slice_impls", since = "1.15.0")]
-unsafe impl<T> SliceIndex<[T]> for ops::RangeFull {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for ops::RangeFull {
     type Output = [T];
 
     #[inline]
@@ -650,7 +662,8 @@ unsafe impl<T> SliceIndex<[T]> for ops::RangeFull {
 /// - the start of the range is greater than the end of the range or
 /// - the end of the range is out of bounds.
 #[stable(feature = "inclusive_range", since = "1.26.0")]
-unsafe impl<T> SliceIndex<[T]> for ops::RangeInclusive<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for ops::RangeInclusive<usize> {
     type Output = [T];
 
     #[inline]
@@ -693,7 +706,8 @@ unsafe impl<T> SliceIndex<[T]> for ops::RangeInclusive<usize> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-unsafe impl<T> SliceIndex<[T]> for range::RangeInclusive<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for range::RangeInclusive<usize> {
     type Output = [T];
 
     #[inline]
@@ -731,7 +745,8 @@ unsafe impl<T> SliceIndex<[T]> for range::RangeInclusive<usize> {
 
 /// The methods `index` and `index_mut` panic if the end of the range is out of bounds.
 #[stable(feature = "inclusive_range", since = "1.26.0")]
-unsafe impl<T> SliceIndex<[T]> for ops::RangeToInclusive<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl<T> const SliceIndex<[T]> for ops::RangeToInclusive<usize> {
     type Output = [T];
 
     #[inline]
diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs
index abcba5a621e23..32419024db953 100644
--- a/library/core/src/slice/mod.rs
+++ b/library/core/src/slice/mod.rs
@@ -568,9 +568,10 @@ impl<T> [T] {
     #[rustc_no_implicit_autorefs]
     #[inline]
     #[must_use]
-    pub fn get<I>(&self, index: I) -> Option<&I::Output>
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
+    pub const fn get<I>(&self, index: I) -> Option<&I::Output>
     where
-        I: SliceIndex<Self>,
+        I: ~const SliceIndex<Self>,
     {
         index.get(self)
     }
@@ -594,9 +595,10 @@ impl<T> [T] {
     #[rustc_no_implicit_autorefs]
     #[inline]
     #[must_use]
-    pub fn get_mut<I>(&mut self, index: I) -> Option<&mut I::Output>
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
+    pub const fn get_mut<I>(&mut self, index: I) -> Option<&mut I::Output>
     where
-        I: SliceIndex<Self>,
+        I: ~const SliceIndex<Self>,
     {
         index.get_mut(self)
     }
@@ -633,9 +635,10 @@ impl<T> [T] {
     #[inline]
     #[must_use]
     #[track_caller]
-    pub unsafe fn get_unchecked<I>(&self, index: I) -> &I::Output
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
+    pub const unsafe fn get_unchecked<I>(&self, index: I) -> &I::Output
     where
-        I: SliceIndex<Self>,
+        I: ~const SliceIndex<Self>,
     {
         // SAFETY: the caller must uphold most of the safety requirements for `get_unchecked`;
         // the slice is dereferenceable because `self` is a safe reference.
@@ -677,9 +680,10 @@ impl<T> [T] {
     #[inline]
     #[must_use]
     #[track_caller]
-    pub unsafe fn get_unchecked_mut<I>(&mut self, index: I) -> &mut I::Output
+    #[rustc_const_unstable(feature = "const_index", issue = "143775")]
+    pub const unsafe fn get_unchecked_mut<I>(&mut self, index: I) -> &mut I::Output
     where
-        I: SliceIndex<Self>,
+        I: ~const SliceIndex<Self>,
     {
         // SAFETY: the caller must uphold the safety requirements for `get_unchecked_mut`;
         // the slice is dereferenceable because `self` is a safe reference.
diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs
index fba3436496e3d..bb0106b9fd940 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)
     }
 
diff --git a/library/core/src/str/traits.rs b/library/core/src/str/traits.rs
index b9559c8317133..42ffc591b5bbf 100644
--- a/library/core/src/str/traits.rs
+++ b/library/core/src/str/traits.rs
@@ -49,9 +49,10 @@ impl PartialOrd for str {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<I> ops::Index<I> for str
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<I> const ops::Index<I> for str
 where
-    I: SliceIndex<str>,
+    I: ~const SliceIndex<str>,
 {
     type Output = I::Output;
 
@@ -62,9 +63,10 @@ where
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<I> ops::IndexMut<I> for str
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+impl<I> const ops::IndexMut<I> for str
 where
-    I: SliceIndex<str>,
+    I: ~const SliceIndex<str>,
 {
     #[inline]
     fn index_mut(&mut self, index: I) -> &mut I::Output {
@@ -92,7 +94,8 @@ const fn str_index_overflow_fail() -> ! {
 ///
 /// Equivalent to `&self[0 .. len]` or `&mut self[0 .. len]`.
 #[stable(feature = "str_checked_slicing", since = "1.20.0")]
-unsafe impl SliceIndex<str> for ops::RangeFull {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for ops::RangeFull {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
@@ -156,7 +159,8 @@ unsafe impl SliceIndex<str> for ops::RangeFull {
 /// // &s[3 .. 100];
 /// ```
 #[stable(feature = "str_checked_slicing", since = "1.20.0")]
-unsafe impl SliceIndex<str> for ops::Range<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for ops::Range<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
@@ -260,7 +264,8 @@ unsafe impl SliceIndex<str> for ops::Range<usize> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-unsafe impl SliceIndex<str> for range::Range<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for range::Range<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
@@ -431,7 +436,8 @@ unsafe impl SliceIndex<str> for (ops::Bound<usize>, ops::Bound<usize>) {
 /// Panics if `end` does not point to the starting byte offset of a
 /// character (as defined by `is_char_boundary`), or if `end > len`.
 #[stable(feature = "str_checked_slicing", since = "1.20.0")]
-unsafe impl SliceIndex<str> for ops::RangeTo<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for ops::RangeTo<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
@@ -499,7 +505,8 @@ unsafe impl SliceIndex<str> for ops::RangeTo<usize> {
 /// Panics if `begin` does not point to the starting byte offset of
 /// a character (as defined by `is_char_boundary`), or if `begin > len`.
 #[stable(feature = "str_checked_slicing", since = "1.20.0")]
-unsafe impl SliceIndex<str> for ops::RangeFrom<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for ops::RangeFrom<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
@@ -554,7 +561,8 @@ unsafe impl SliceIndex<str> for ops::RangeFrom<usize> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-unsafe impl SliceIndex<str> for range::RangeFrom<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for range::RangeFrom<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
@@ -625,7 +633,8 @@ unsafe impl SliceIndex<str> for range::RangeFrom<usize> {
 /// to the ending byte offset of a character (`end + 1` is either a starting
 /// byte offset or equal to `len`), if `begin > end`, or if `end >= len`.
 #[stable(feature = "inclusive_range", since = "1.26.0")]
-unsafe impl SliceIndex<str> for ops::RangeInclusive<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for ops::RangeInclusive<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
@@ -662,7 +671,8 @@ unsafe impl SliceIndex<str> for ops::RangeInclusive<usize> {
 }
 
 #[unstable(feature = "new_range_api", issue = "125687")]
-unsafe impl SliceIndex<str> for range::RangeInclusive<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for range::RangeInclusive<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
@@ -713,7 +723,8 @@ unsafe impl SliceIndex<str> for range::RangeInclusive<usize> {
 /// (`end + 1` is either a starting byte offset as defined by
 /// `is_char_boundary`, or equal to `len`), or if `end >= len`.
 #[stable(feature = "inclusive_range", since = "1.26.0")]
-unsafe impl SliceIndex<str> for ops::RangeToInclusive<usize> {
+#[rustc_const_unstable(feature = "const_index", issue = "143775")]
+unsafe impl const SliceIndex<str> for ops::RangeToInclusive<usize> {
     type Output = str;
     #[inline]
     fn get(self, slice: &str) -> Option<&Self::Output> {
diff --git a/tests/ui/consts/const-eval/ub-slice-get-unchecked.rs b/tests/ui/consts/const-eval/ub-slice-get-unchecked.rs
index e805ac01c9d06..ad2b49e60498d 100644
--- a/tests/ui/consts/const-eval/ub-slice-get-unchecked.rs
+++ b/tests/ui/consts/const-eval/ub-slice-get-unchecked.rs
@@ -1,9 +1,10 @@
-//@ known-bug: #110395
+#![feature(const_index, const_trait_impl)]
 
 const A: [(); 5] = [(), (), (), (), ()];
 
 // Since the indexing is on a ZST, the addresses are all fine,
 // but we should still catch the bad range.
 const B: &[()] = unsafe { A.get_unchecked(3..1) };
+//~^ ERROR: slice::get_unchecked requires that the range is within the slice
 
 fn main() {}
diff --git a/tests/ui/consts/const-eval/ub-slice-get-unchecked.stderr b/tests/ui/consts/const-eval/ub-slice-get-unchecked.stderr
index 6e428079afe8e..88ea310f19c68 100644
--- a/tests/ui/consts/const-eval/ub-slice-get-unchecked.stderr
+++ b/tests/ui/consts/const-eval/ub-slice-get-unchecked.stderr
@@ -1,11 +1,11 @@
-error[E0015]: cannot call non-const method `core::slice::<impl [()]>::get_unchecked::<std::ops::Range<usize>>` in constants
-  --> $DIR/ub-slice-get-unchecked.rs:7:29
+error[E0080]: evaluation panicked: unsafe precondition(s) violated: slice::get_unchecked requires that the range is within the slice
+              
+              This indicates a bug in the program. This Undefined Behavior check is optional, and cannot be relied on for safety.
+  --> $DIR/ub-slice-get-unchecked.rs:7:27
    |
 LL | const B: &[()] = unsafe { A.get_unchecked(3..1) };
-   |                             ^^^^^^^^^^^^^^^^^^^
-   |
-   = note: calls in constants are limited to constant functions, tuple structs and tuple variants
+   |                           ^^^^^^^^^^^^^^^^^^^^^ evaluation of `B` failed here
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/issue-94675.rs b/tests/ui/consts/issue-94675.rs
index 87c8b04452bac..22791e7d15e5d 100644
--- a/tests/ui/consts/issue-94675.rs
+++ b/tests/ui/consts/issue-94675.rs
@@ -7,7 +7,9 @@ struct Foo<'a> {
 impl<'a> Foo<'a> {
     const fn spam(&mut self, baz: &mut Vec<u32>) {
         self.bar[0] = baz.len();
-        //~^ ERROR: cannot call
+        //~^ ERROR: `Vec<usize>: [const] Index<_>` is not satisfied
+        //~| ERROR: `Vec<usize>: [const] Index<usize>` is not satisfied
+        //~| ERROR: `Vec<usize>: [const] IndexMut<usize>` is not satisfied
     }
 }
 
diff --git a/tests/ui/consts/issue-94675.stderr b/tests/ui/consts/issue-94675.stderr
index 63a86b456332f..608ce0cfef012 100644
--- a/tests/ui/consts/issue-94675.stderr
+++ b/tests/ui/consts/issue-94675.stderr
@@ -1,13 +1,24 @@
-error[E0015]: cannot call non-const operator in constant functions
-  --> $DIR/issue-94675.rs:9:17
+error[E0277]: the trait bound `Vec<usize>: [const] Index<_>` is not satisfied
+  --> $DIR/issue-94675.rs:9:9
    |
 LL |         self.bar[0] = baz.len();
-   |                 ^^^
+   |         ^^^^^^^^^^^
+
+error[E0277]: the trait bound `Vec<usize>: [const] IndexMut<usize>` is not satisfied
+  --> $DIR/issue-94675.rs:9:9
+   |
+LL |         self.bar[0] = baz.len();
+   |         ^^^^^^^^^^^
+
+error[E0277]: the trait bound `Vec<usize>: [const] Index<usize>` is not satisfied
+  --> $DIR/issue-94675.rs:9:9
+   |
+LL |         self.bar[0] = baz.len();
+   |         ^^^^^^^^^^^
    |
-note: impl defined here, but it is not `const`
-  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+note: required by a bound in `std::ops::IndexMut::index_mut`
+  --> $SRC_DIR/core/src/ops/index.rs:LL:COL
 
-error: aborting due to 1 previous error
+error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/parser/issues/issue-35813-postfix-after-cast.rs b/tests/ui/parser/issues/issue-35813-postfix-after-cast.rs
index 316c612940c9f..439793ea8f72e 100644
--- a/tests/ui/parser/issues/issue-35813-postfix-after-cast.rs
+++ b/tests/ui/parser/issues/issue-35813-postfix-after-cast.rs
@@ -1,6 +1,6 @@
 //@ edition:2018
 #![crate_type = "lib"]
-#![feature(type_ascription)]
+#![feature(type_ascription, const_index, const_trait_impl)]
 use std::future::Future;
 use std::pin::Pin;
 
@@ -129,7 +129,6 @@ pub fn inside_block() {
 
 static bar: &[i32] = &(&[1,2,3] as &[i32][0..1]);
 //~^ ERROR: cast cannot be followed by indexing
-//~| ERROR: cannot call non-const operator in statics
 
 static bar2: &[i32] = &(&[1i32,2,3]: &[i32; 3][0..1]);
 //~^ ERROR: expected one of
diff --git a/tests/ui/parser/issues/issue-35813-postfix-after-cast.stderr b/tests/ui/parser/issues/issue-35813-postfix-after-cast.stderr
index 64cf8baf9a5d4..ce7129da9371f 100644
--- a/tests/ui/parser/issues/issue-35813-postfix-after-cast.stderr
+++ b/tests/ui/parser/issues/issue-35813-postfix-after-cast.stderr
@@ -219,13 +219,13 @@ LL | static bar: &[i32] = &((&[1,2,3] as &[i32])[0..1]);
    |                        +                  +
 
 error: expected one of `)`, `,`, `.`, `?`, or an operator, found `:`
-  --> $DIR/issue-35813-postfix-after-cast.rs:134:36
+  --> $DIR/issue-35813-postfix-after-cast.rs:133:36
    |
 LL | static bar2: &[i32] = &(&[1i32,2,3]: &[i32; 3][0..1]);
    |                                    ^ expected one of `)`, `,`, `.`, `?`, or an operator
 
 error: cast cannot be followed by `?`
-  --> $DIR/issue-35813-postfix-after-cast.rs:139:5
+  --> $DIR/issue-35813-postfix-after-cast.rs:138:5
    |
 LL |     Err(0u64) as Result<u64,u64>?;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -236,25 +236,25 @@ LL |     (Err(0u64) as Result<u64,u64>)?;
    |     +                            +
 
 error: expected one of `.`, `;`, `?`, `}`, or an operator, found `:`
-  --> $DIR/issue-35813-postfix-after-cast.rs:141:14
+  --> $DIR/issue-35813-postfix-after-cast.rs:140:14
    |
 LL |     Err(0u64): Result<u64,u64>?;
    |              ^ expected one of `.`, `;`, `?`, `}`, or an operator
 
 error: expected identifier, found `:`
-  --> $DIR/issue-35813-postfix-after-cast.rs:153:13
+  --> $DIR/issue-35813-postfix-after-cast.rs:152:13
    |
 LL |     drop_ptr: F();
    |             ^ expected identifier
 
 error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `:`
-  --> $DIR/issue-35813-postfix-after-cast.rs:160:13
+  --> $DIR/issue-35813-postfix-after-cast.rs:159:13
    |
 LL |     drop_ptr: fn(u8);
    |             ^ expected one of 8 possible tokens
 
 error: cast cannot be followed by a function call
-  --> $DIR/issue-35813-postfix-after-cast.rs:166:5
+  --> $DIR/issue-35813-postfix-after-cast.rs:165:5
    |
 LL |     drop as fn(u8)(0);
    |     ^^^^^^^^^^^^^^
@@ -265,13 +265,13 @@ LL |     (drop as fn(u8))(0);
    |     +              +
 
 error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `:`
-  --> $DIR/issue-35813-postfix-after-cast.rs:168:13
+  --> $DIR/issue-35813-postfix-after-cast.rs:167:13
    |
 LL |     drop_ptr: fn(u8)(0);
    |             ^ expected one of 8 possible tokens
 
 error: cast cannot be followed by `.await`
-  --> $DIR/issue-35813-postfix-after-cast.rs:173:5
+  --> $DIR/issue-35813-postfix-after-cast.rs:172:5
    |
 LL |     Box::pin(noop()) as Pin<Box<dyn Future<Output = ()>>>.await;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -282,13 +282,13 @@ LL |     (Box::pin(noop()) as Pin<Box<dyn Future<Output = ()>>>).await;
    |     +                                                     +
 
 error: expected one of `.`, `;`, `?`, `}`, or an operator, found `:`
-  --> $DIR/issue-35813-postfix-after-cast.rs:176:21
+  --> $DIR/issue-35813-postfix-after-cast.rs:175:21
    |
 LL |     Box::pin(noop()): Pin<Box<_>>.await;
    |                     ^ expected one of `.`, `;`, `?`, `}`, or an operator
 
 error: cast cannot be followed by a field access
-  --> $DIR/issue-35813-postfix-after-cast.rs:188:5
+  --> $DIR/issue-35813-postfix-after-cast.rs:187:5
    |
 LL |     Foo::default() as Foo.bar;
    |     ^^^^^^^^^^^^^^^^^^^^^
@@ -299,7 +299,7 @@ LL |     (Foo::default() as Foo).bar;
    |     +                     +
 
 error: expected one of `.`, `;`, `?`, `}`, or an operator, found `:`
-  --> $DIR/issue-35813-postfix-after-cast.rs:190:19
+  --> $DIR/issue-35813-postfix-after-cast.rs:189:19
    |
 LL |     Foo::default(): Foo.bar;
    |                   ^ expected one of `.`, `;`, `?`, `}`, or an operator
@@ -322,21 +322,11 @@ LL |         if true { 33 } else { 44 }: i32.max(0)
    |                                   ^ expected one of `,`, `.`, `?`, or an operator
 
 error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
-  --> $DIR/issue-35813-postfix-after-cast.rs:151:13
+  --> $DIR/issue-35813-postfix-after-cast.rs:150:13
    |
 LL |     drop as F();
    |             ^^^ only `Fn` traits may use parentheses
 
-error[E0015]: cannot call non-const operator in statics
-  --> $DIR/issue-35813-postfix-after-cast.rs:130:42
-   |
-LL | static bar: &[i32] = &(&[1,2,3] as &[i32][0..1]);
-   |                                          ^^^^^^
-   |
-   = note: calls in statics are limited to constant functions, tuple structs and tuple variants
-   = note: consider wrapping this expression in `std::sync::LazyLock::new(|| ...)`
-
-error: aborting due to 40 previous errors
+error: aborting due to 39 previous errors
 
-Some errors have detailed explanations: E0015, E0214.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0214`.