diff --git a/src/libcollections/str.rs b/src/libcollections/str.rs
index 2e96b941c08..bf568fd92d5 100644
--- a/src/libcollections/str.rs
+++ b/src/libcollections/str.rs
@@ -903,21 +903,21 @@ mod tests {
     #[test]
     fn test_find() {
         assert_eq!("hello".find('l'), Some(2u));
-        assert_eq!("hello".find(|c:char| c == 'o'), Some(4u));
+        assert_eq!("hello".find(|&: c:char| c == 'o'), Some(4u));
         assert!("hello".find('x').is_none());
-        assert!("hello".find(|c:char| c == 'x').is_none());
+        assert!("hello".find(|&: c:char| c == 'x').is_none());
         assert_eq!("ประเทศไทย中华Việt Nam".find('华'), Some(30u));
-        assert_eq!("ประเทศไทย中华Việt Nam".find(|c: char| c == '华'), Some(30u));
+        assert_eq!("ประเทศไทย中华Việt Nam".find(|&: c: char| c == '华'), Some(30u));
     }
 
     #[test]
     fn test_rfind() {
         assert_eq!("hello".rfind('l'), Some(3u));
-        assert_eq!("hello".rfind(|c:char| c == 'o'), Some(4u));
+        assert_eq!("hello".rfind(|&: c:char| c == 'o'), Some(4u));
         assert!("hello".rfind('x').is_none());
-        assert!("hello".rfind(|c:char| c == 'x').is_none());
+        assert!("hello".rfind(|&: c:char| c == 'x').is_none());
         assert_eq!("ประเทศไทย中华Việt Nam".rfind('华'), Some(30u));
-        assert_eq!("ประเทศไทย中华Việt Nam".rfind(|c: char| c == '华'), Some(30u));
+        assert_eq!("ประเทศไทย中华Việt Nam".rfind(|&: c: char| c == '华'), Some(30u));
     }
 
     #[test]
@@ -1281,7 +1281,7 @@ mod tests {
         assert_eq!("11foo1bar11".trim_left_chars('1'), "foo1bar11");
         let chars: &[char] = &['1', '2'];
         assert_eq!("12foo1bar12".trim_left_chars(chars), "foo1bar12");
-        assert_eq!("123foo1bar123".trim_left_chars(|c: char| c.is_numeric()), "foo1bar123");
+        assert_eq!("123foo1bar123".trim_left_chars(|&: c: char| c.is_numeric()), "foo1bar123");
     }
 
     #[test]
@@ -1296,7 +1296,7 @@ mod tests {
         assert_eq!("11foo1bar11".trim_right_chars('1'), "11foo1bar");
         let chars: &[char] = &['1', '2'];
         assert_eq!("12foo1bar12".trim_right_chars(chars), "12foo1bar");
-        assert_eq!("123foo1bar123".trim_right_chars(|c: char| c.is_numeric()), "123foo1bar");
+        assert_eq!("123foo1bar123".trim_right_chars(|&: c: char| c.is_numeric()), "123foo1bar");
     }
 
     #[test]
@@ -1311,7 +1311,7 @@ mod tests {
         assert_eq!("11foo1bar11".trim_chars('1'), "foo1bar");
         let chars: &[char] = &['1', '2'];
         assert_eq!("12foo1bar12".trim_chars(chars), "foo1bar");
-        assert_eq!("123foo1bar123".trim_chars(|c: char| c.is_numeric()), "foo1bar");
+        assert_eq!("123foo1bar123".trim_chars(|&: c: char| c.is_numeric()), "foo1bar");
     }
 
     #[test]
@@ -1787,14 +1787,14 @@ mod tests {
         let split: Vec<&str> = data.splitn(3, ' ').collect();
         assert_eq!(split, vec!["\nMäry", "häd", "ä", "little lämb\nLittle lämb\n"]);
 
-        let split: Vec<&str> = data.splitn(3, |c: char| c == ' ').collect();
+        let split: Vec<&str> = data.splitn(3, |&: c: char| c == ' ').collect();
         assert_eq!(split, vec!["\nMäry", "häd", "ä", "little lämb\nLittle lämb\n"]);
 
         // Unicode
         let split: Vec<&str> = data.splitn(3, 'ä').collect();
         assert_eq!(split, vec!["\nM", "ry h", "d ", " little lämb\nLittle lämb\n"]);
 
-        let split: Vec<&str> = data.splitn(3, |c: char| c == 'ä').collect();
+        let split: Vec<&str> = data.splitn(3, |&: c: char| c == 'ä').collect();
         assert_eq!(split, vec!["\nM", "ry h", "d ", " little lämb\nLittle lämb\n"]);
     }
 
@@ -2588,7 +2588,7 @@ mod bench {
         let s = "Mary had a little lamb, Little lamb, little-lamb.";
         let len = s.split(' ').count();
 
-        b.iter(|| assert_eq!(s.split(|c: char| c == ' ').count(), len));
+        b.iter(|| assert_eq!(s.split(|&: c: char| c == ' ').count(), len));
     }
 
     #[bench]