diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs
index bbfe7e58ef4..a86da53b372 100644
--- a/src/libcore/slice.rs
+++ b/src/libcore/slice.rs
@@ -140,11 +140,11 @@ impl<T> SliceExt for [T] {
             if mem::size_of::<T>() == 0 {
                 Iter {ptr: p,
                       end: (p as usize + self.len()) as *const T,
-                      marker: marker::ContravariantLifetime::<'a>}
+                      _marker: marker::PhantomData}
             } else {
                 Iter {ptr: p,
                       end: p.offset(self.len() as isize),
-                      marker: marker::ContravariantLifetime::<'a>}
+                      _marker: marker::PhantomData}
             }
         }
     }
@@ -279,11 +279,11 @@ impl<T> SliceExt for [T] {
             if mem::size_of::<T>() == 0 {
                 IterMut {ptr: p,
                          end: (p as usize + self.len()) as *mut T,
-                         marker: marker::ContravariantLifetime::<'a>}
+                         _marker: marker::PhantomData}
             } else {
                 IterMut {ptr: p,
                          end: p.offset(self.len() as isize),
-                         marker: marker::ContravariantLifetime::<'a>}
+                         _marker: marker::PhantomData}
             }
         }
     }
@@ -733,7 +733,7 @@ macro_rules! make_slice {
 pub struct Iter<'a, T: 'a> {
     ptr: *const T,
     end: *const T,
-    marker: marker::ContravariantLifetime<'a>
+    _marker: marker::PhantomData<&'a T>,
 }
 
 #[unstable(feature = "core")]
@@ -790,7 +790,7 @@ impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> Clone for Iter<'a, T> {
-    fn clone(&self) -> Iter<'a, T> { Iter { ptr: self.ptr, end: self.end, marker: self.marker } }
+    fn clone(&self) -> Iter<'a, T> { Iter { ptr: self.ptr, end: self.end, _marker: self._marker } }
 }
 
 #[unstable(feature = "core", reason = "trait is experimental")]
@@ -823,7 +823,7 @@ impl<'a, T> RandomAccessIterator for Iter<'a, T> {
 pub struct IterMut<'a, T: 'a> {
     ptr: *mut T,
     end: *mut T,
-    marker: marker::ContravariantLifetime<'a>,
+    _marker: marker::PhantomData<&'a mut T>,
 }