diff --git a/src/test/bench/core-map.rs b/src/test/bench/core-map.rs
index fd1110abb224..730b175a4994 100644
--- a/src/test/bench/core-map.rs
+++ b/src/test/bench/core-map.rs
@@ -27,7 +27,7 @@ fn timed(label: &str, f: &fn()) {
     io::println(fmt!("  %s: %f", label, end - start));
 }
 
-fn ascending<M: Map<uint, uint>>(map: &mut M, n_keys: uint) {
+fn ascending<M: MutableMap<uint, uint>>(map: &mut M, n_keys: uint) {
     io::println(" Ascending integers:");
 
     do timed("insert") {
@@ -49,7 +49,7 @@ fn ascending<M: Map<uint, uint>>(map: &mut M, n_keys: uint) {
     }
 }
 
-fn descending<M: Map<uint, uint>>(map: &mut M, n_keys: uint) {
+fn descending<M: MutableMap<uint, uint>>(map: &mut M, n_keys: uint) {
     io::println(" Descending integers:");
 
     do timed("insert") {
@@ -71,7 +71,7 @@ fn descending<M: Map<uint, uint>>(map: &mut M, n_keys: uint) {
     }
 }
 
-fn vector<M: Map<uint, uint>>(map: &mut M, n_keys: uint, dist: &[uint]) {
+fn vector<M: MutableMap<uint, uint>>(map: &mut M, n_keys: uint, dist: &[uint]) {
 
     do timed("insert") {
         for uint::range(0, n_keys) |i| {
diff --git a/src/test/bench/core-set.rs b/src/test/bench/core-set.rs
index a0b742515494..461f4caa30b0 100644
--- a/src/test/bench/core-set.rs
+++ b/src/test/bench/core-set.rs
@@ -36,7 +36,7 @@ fn timed(result: &mut float, op: &fn()) {
 }
 
 impl Results {
-    pub fn bench_int<T:Set<uint>,
+    pub fn bench_int<T:MutableSet<uint>,
                  R: rand::Rng>(
                  &mut self,
                  rng: &mut R,
@@ -79,7 +79,7 @@ impl Results {
         }
     }
 
-    pub fn bench_str<T:Set<~str>,
+    pub fn bench_str<T:MutableSet<~str>,
                  R:rand::Rng>(
                  &mut self,
                  rng: &mut R,