diff --git a/src/libcore/task.rs b/src/libcore/task.rs
index 919faf40d83..cecc7a51ea7 100644
--- a/src/libcore/task.rs
+++ b/src/libcore/task.rs
@@ -1557,7 +1557,7 @@ unsafe fn local_set<T: Owned>(
         }
         None => {
             // Find an empty slot. If not, grow the vector.
-            match (*map).position(|x| x.is_None()) {
+            match (*map).position(|x| x.is_none()) {
                 Some(empty_index) => (*map).set_elt(empty_index, new_entry),
                 None => (*map).push(new_entry)
             }
@@ -2280,7 +2280,7 @@ fn test_tls_multitask() unsafe {
     fn my_key(+_x: @~str) { }
     local_data_set(my_key, @~"parent data");
     do task::spawn unsafe {
-        assert local_data_get(my_key).is_None(); // TLS shouldn't carry over.
+        assert local_data_get(my_key).is_none(); // TLS shouldn't carry over.
         local_data_set(my_key, @~"child data");
         assert *(local_data_get(my_key).get()) == ~"child data";
         // should be cleaned up for us
@@ -2305,7 +2305,7 @@ fn test_tls_pop() unsafe {
     local_data_set(my_key, @~"weasel");
     assert *(local_data_pop(my_key).get()) == ~"weasel";
     // Pop must remove the data from the map.
-    assert local_data_pop(my_key).is_None();
+    assert local_data_pop(my_key).is_none();
 }
 
 #[test]