diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs
index 969c912128d06..542dfcbe6284f 100644
--- a/src/libcore/slice.rs
+++ b/src/libcore/slice.rs
@@ -523,7 +523,7 @@ impl<T> SliceExt for [T] {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::Index<usize> for [T] {
     type Output = T;
 
@@ -534,7 +534,7 @@ impl<T> ops::Index<usize> for [T] {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::IndexMut<usize> for [T] {
     #[inline]
     fn index_mut(&mut self, index: usize) -> &mut T {
@@ -568,7 +568,7 @@ fn slice_index_order_fail(index: usize, end: usize) -> ! {
 /// Requires that `begin <= end` and `end <= self.len()`,
 /// otherwise slicing will panic.
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::Index<ops::Range<usize>> for [T] {
     type Output = [T];
 
@@ -595,7 +595,7 @@ impl<T> ops::Index<ops::Range<usize>> for [T] {
 ///
 /// Equivalent to `&self[0 .. end]`
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::Index<ops::RangeTo<usize>> for [T] {
     type Output = [T];
 
@@ -611,7 +611,7 @@ impl<T> ops::Index<ops::RangeTo<usize>> for [T] {
 ///
 /// Equivalent to `&self[begin .. self.len()]`
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::Index<ops::RangeFrom<usize>> for [T] {
     type Output = [T];
 
@@ -637,7 +637,7 @@ impl<T> ops::Index<RangeFull> for [T] {
 }
 
 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::Index<ops::RangeInclusive<usize>> for [T] {
     type Output = [T];
 
@@ -653,7 +653,7 @@ impl<T> ops::Index<ops::RangeInclusive<usize>> for [T] {
     }
 }
 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::Index<ops::RangeToInclusive<usize>> for [T] {
     type Output = [T];
 
@@ -674,7 +674,7 @@ impl<T> ops::Index<ops::RangeToInclusive<usize>> for [T] {
 /// Requires that `begin <= end` and `end <= self.len()`,
 /// otherwise slicing will panic.
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::IndexMut<ops::Range<usize>> for [T] {
     #[inline]
     fn index_mut(&mut self, index: ops::Range<usize>) -> &mut [T] {
@@ -699,7 +699,7 @@ impl<T> ops::IndexMut<ops::Range<usize>> for [T] {
 ///
 /// Equivalent to `&mut self[0 .. end]`
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::IndexMut<ops::RangeTo<usize>> for [T] {
     #[inline]
     fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut [T] {
@@ -713,7 +713,7 @@ impl<T> ops::IndexMut<ops::RangeTo<usize>> for [T] {
 ///
 /// Equivalent to `&mut self[begin .. self.len()]`
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::IndexMut<ops::RangeFrom<usize>> for [T] {
     #[inline]
     fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut [T] {
@@ -736,7 +736,7 @@ impl<T> ops::IndexMut<RangeFull> for [T] {
 }
 
 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::IndexMut<ops::RangeInclusive<usize>> for [T] {
     #[inline]
     fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut [T] {
@@ -750,7 +750,7 @@ impl<T> ops::IndexMut<ops::RangeInclusive<usize>> for [T] {
     }
 }
 #[unstable(feature = "inclusive_range", reason = "recently added, follows RFC", issue = "28237")]
-#[rustc_on_unimplemented = "slice indices are of type usize"]
+#[rustc_on_unimplemented = "slice indices are of type `usize`"]
 impl<T> ops::IndexMut<ops::RangeToInclusive<usize>> for [T] {
     #[inline]
     fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut [T] {
diff --git a/src/test/compile-fail/on-unimplemented/libcore-index.rs b/src/test/compile-fail/on-unimplemented/slice-index.rs
similarity index 85%
rename from src/test/compile-fail/on-unimplemented/libcore-index.rs
rename to src/test/compile-fail/on-unimplemented/slice-index.rs
index 6a8356040d4b4..6a8f9d471e169 100644
--- a/src/test/compile-fail/on-unimplemented/libcore-index.rs
+++ b/src/test/compile-fail/on-unimplemented/slice-index.rs
@@ -18,7 +18,7 @@ use std::ops::Index;
 fn main() {
     let x = &[1, 2, 3] as &[i32];
     x[1i32]; //~ ERROR E0277
-             //~| NOTE slice indices are of type usize
+             //~| NOTE slice indices are of type `usize`
     x[..1i32]; //~ ERROR E0277
-               //~| NOTE slice indices are of type usize
+               //~| NOTE slice indices are of type `usize`
 }