auto merge of #19378 : japaric/rust/no-as-slice, r=alexcrichton

Now that we have an overloaded comparison (`==`) operator, and that `Vec`/`String` deref to `[T]`/`str` on method calls, many `as_slice()`/`as_mut_slice()`/`to_string()` calls have become redundant. This patch removes them. These were the most common patterns:

- `assert_eq(test_output.as_slice(), "ground truth")` -> `assert_eq(test_output, "ground truth")`
- `assert_eq(test_output, "ground truth".to_string())` -> `assert_eq(test_output, "ground truth")`
- `vec.as_mut_slice().sort()` -> `vec.sort()`
- `vec.as_slice().slice(from, to)` -> `vec.slice(from_to)`

---

Note that e.g. `a_string.push_str(b_string.as_slice())` has been left untouched in this PR, since we first need to settle down whether we want to favor the `&*b_string` or the `b_string[]` notation.

This is rebased on top of #19167

cc @alexcrichton @aturon 

27 files changed, 215 insertions, 218 deletions

diff --git a/src/libstd/ascii.rs b/src/libstd/ascii.rs
index 8fc3c23e88f..2872f74cf88 100644
--- a/src/libstd/ascii.rs
+++ b/src/libstd/ascii.rs
@@ -678,16 +678,16 @@ mod tests {
         assert_eq!(test.to_ascii(), b);
         assert_eq!("( ;".to_ascii(), b);
         let v = vec![40u8, 32u8, 59u8];
-        assert_eq!(v.as_slice().to_ascii(), b);
-        assert_eq!("( ;".to_string().as_slice().to_ascii(), b);
+        assert_eq!(v.to_ascii(), b);
+        assert_eq!("( ;".to_string().to_ascii(), b);
 
-        assert_eq!("abCDef&?#".to_ascii().to_lowercase().into_string(), "abcdef&?#".to_string());
-        assert_eq!("abCDef&?#".to_ascii().to_uppercase().into_string(), "ABCDEF&?#".to_string());
+        assert_eq!("abCDef&?#".to_ascii().to_lowercase().into_string(), "abcdef&?#");
+        assert_eq!("abCDef&?#".to_ascii().to_uppercase().into_string(), "ABCDEF&?#");
 
-        assert_eq!("".to_ascii().to_lowercase().into_string(), "".to_string());
-        assert_eq!("YMCA".to_ascii().to_lowercase().into_string(), "ymca".to_string());
+        assert_eq!("".to_ascii().to_lowercase().into_string(), "");
+        assert_eq!("YMCA".to_ascii().to_lowercase().into_string(), "ymca");
         let mixed = "abcDEFxyz:.;".to_ascii();
-        assert_eq!(mixed.to_uppercase().into_string(), "ABCDEFXYZ:.;".to_string());
+        assert_eq!(mixed.to_uppercase().into_string(), "ABCDEFXYZ:.;");
 
         assert!("aBcDeF&?#".to_ascii().eq_ignore_case("AbCdEf&?#".to_ascii()));
 
@@ -699,12 +699,12 @@ mod tests {
 
     #[test]
     fn test_ascii_vec_ng() {
-        assert_eq!("abCDef&?#".to_ascii().to_lowercase().into_string(), "abcdef&?#".to_string());
-        assert_eq!("abCDef&?#".to_ascii().to_uppercase().into_string(), "ABCDEF&?#".to_string());
-        assert_eq!("".to_ascii().to_lowercase().into_string(), "".to_string());
-        assert_eq!("YMCA".to_ascii().to_lowercase().into_string(), "ymca".to_string());
+        assert_eq!("abCDef&?#".to_ascii().to_lowercase().into_string(), "abcdef&?#");
+        assert_eq!("abCDef&?#".to_ascii().to_uppercase().into_string(), "ABCDEF&?#");
+        assert_eq!("".to_ascii().to_lowercase().into_string(), "");
+        assert_eq!("YMCA".to_ascii().to_lowercase().into_string(), "ymca");
         let mixed = "abcDEFxyz:.;".to_ascii();
-        assert_eq!(mixed.to_uppercase().into_string(), "ABCDEFXYZ:.;".to_string());
+        assert_eq!(mixed.to_uppercase().into_string(), "ABCDEFXYZ:.;");
     }
 
     #[test]
@@ -721,8 +721,8 @@ mod tests {
 
     #[test]
     fn test_ascii_into_string() {
-        assert_eq!(vec2ascii![40, 32, 59].into_string(), "( ;".to_string());
-        assert_eq!(vec2ascii!(40, 32, 59).into_string(), "( ;".to_string());
+        assert_eq!(vec2ascii![40, 32, 59].into_string(), "( ;");
+        assert_eq!(vec2ascii!(40, 32, 59).into_string(), "( ;");
     }
 
     #[test]
@@ -774,14 +774,14 @@ mod tests {
 
     #[test]
     fn test_to_ascii_upper() {
-        assert_eq!("url()URL()uRl()ürl".to_ascii_upper(), "URL()URL()URL()üRL".to_string());
-        assert_eq!("hıKß".to_ascii_upper(), "HıKß".to_string());
+        assert_eq!("url()URL()uRl()ürl".to_ascii_upper(), "URL()URL()URL()üRL");
+        assert_eq!("hıKß".to_ascii_upper(), "HıKß");
 
         let mut i = 0;
         while i <= 500 {
             let upper = if 'a' as u32 <= i && i <= 'z' as u32 { i + 'A' as u32 - 'a' as u32 }
                         else { i };
-            assert_eq!((from_u32(i).unwrap()).to_string().as_slice().to_ascii_upper(),
+            assert_eq!((from_u32(i).unwrap()).to_string().to_ascii_upper(),
                        (from_u32(upper).unwrap()).to_string())
             i += 1;
         }
@@ -789,15 +789,15 @@ mod tests {
 
     #[test]
     fn test_to_ascii_lower() {
-        assert_eq!("url()URL()uRl()Ürl".to_ascii_lower(), "url()url()url()Ürl".to_string());
+        assert_eq!("url()URL()uRl()Ürl".to_ascii_lower(), "url()url()url()Ürl");
         // Dotted capital I, Kelvin sign, Sharp S.
-        assert_eq!("HİKß".to_ascii_lower(), "hİKß".to_string());
+        assert_eq!("HİKß".to_ascii_lower(), "hİKß");
 
         let mut i = 0;
         while i <= 500 {
             let lower = if 'A' as u32 <= i && i <= 'Z' as u32 { i + 'a' as u32 - 'A' as u32 }
                         else { i };
-            assert_eq!((from_u32(i).unwrap()).to_string().as_slice().to_ascii_lower(),
+            assert_eq!((from_u32(i).unwrap()).to_string().to_ascii_lower(),
                        (from_u32(lower).unwrap()).to_string())
             i += 1;
         }
@@ -807,7 +807,7 @@ mod tests {
     fn test_into_ascii_upper() {
         assert_eq!(("url()URL()uRl()ürl".to_string()).into_ascii_upper(),
                    "URL()URL()URL()üRL".to_string());
-        assert_eq!(("hıKß".to_string()).into_ascii_upper(), "HıKß".to_string());
+        assert_eq!(("hıKß".to_string()).into_ascii_upper(), "HıKß");
 
         let mut i = 0;
         while i <= 500 {
@@ -822,9 +822,9 @@ mod tests {
     #[test]
     fn test_into_ascii_lower() {
         assert_eq!(("url()URL()uRl()Ürl".to_string()).into_ascii_lower(),
-                   "url()url()url()Ürl".to_string());
+                   "url()url()url()Ürl");
         // Dotted capital I, Kelvin sign, Sharp S.
-        assert_eq!(("HİKß".to_string()).into_ascii_lower(), "hİKß".to_string());
+        assert_eq!(("HİKß".to_string()).into_ascii_lower(), "hİKß");
 
         let mut i = 0;
         while i <= 500 {
@@ -851,7 +851,7 @@ mod tests {
             let c = i;
             let lower = if 'A' as u32 <= c && c <= 'Z' as u32 { c + 'a' as u32 - 'A' as u32 }
                         else { c };
-            assert!((from_u32(i).unwrap()).to_string().as_slice().eq_ignore_ascii_case(
+            assert!((from_u32(i).unwrap()).to_string().eq_ignore_ascii_case(
                     (from_u32(lower).unwrap()).to_string().as_slice()));
             i += 1;
         }
@@ -860,12 +860,12 @@ mod tests {
     #[test]
     fn test_to_string() {
         let s = Ascii{ chr: b't' }.to_string();
-        assert_eq!(s, "t".to_string());
+        assert_eq!(s, "t");
     }
 
     #[test]
     fn test_show() {
         let c = Ascii { chr: b't' };
-        assert_eq!(format!("{}", c), "t".to_string());
+        assert_eq!(format!("{}", c), "t");
     }
 }
diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index 8f879bd50d0..a8dce232d26 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -1548,7 +1548,7 @@ mod test_map {
 
             DROP_VECTOR.with(|v| {
                 for i in range(0u, 200) {
-                    assert_eq!(v.borrow().as_slice()[i], 0);
+                    assert_eq!(v.borrow()[i], 0);
                 }
             });
 
@@ -1560,7 +1560,7 @@ mod test_map {
 
             DROP_VECTOR.with(|v| {
                 for i in range(0u, 200) {
-                    assert_eq!(v.borrow().as_slice()[i], 1);
+                    assert_eq!(v.borrow()[i], 1);
                 }
             });
 
@@ -1571,27 +1571,27 @@ mod test_map {
                 assert!(v.is_some());
 
                 DROP_VECTOR.with(|v| {
-                    assert_eq!(v.borrow().as_slice()[i], 1);
-                    assert_eq!(v.borrow().as_slice()[i+100], 1);
+                    assert_eq!(v.borrow()[i], 1);
+                    assert_eq!(v.borrow()[i+100], 1);
                 });
             }
 
             DROP_VECTOR.with(|v| {
                 for i in range(0u, 50) {
-                    assert_eq!(v.borrow().as_slice()[i], 0);
-                    assert_eq!(v.borrow().as_slice()[i+100], 0);
+                    assert_eq!(v.borrow()[i], 0);
+                    assert_eq!(v.borrow()[i+100], 0);
                 }
 
                 for i in range(50u, 100) {
-                    assert_eq!(v.borrow().as_slice()[i], 1);
-                    assert_eq!(v.borrow().as_slice()[i+100], 1);
+                    assert_eq!(v.borrow()[i], 1);
+                    assert_eq!(v.borrow()[i+100], 1);
                 }
             });
         }
 
         DROP_VECTOR.with(|v| {
             for i in range(0u, 200) {
-                assert_eq!(v.borrow().as_slice()[i], 0);
+                assert_eq!(v.borrow()[i], 0);
             }
         });
     }
@@ -1607,7 +1607,7 @@ mod test_map {
 
             DROP_VECTOR.with(|v| {
                 for i in range(0u, 200) {
-                    assert_eq!(v.borrow().as_slice()[i], 0);
+                    assert_eq!(v.borrow()[i], 0);
                 }
             });
 
@@ -1619,7 +1619,7 @@ mod test_map {
 
             DROP_VECTOR.with(|v| {
                 for i in range(0u, 200) {
-                    assert_eq!(v.borrow().as_slice()[i], 1);
+                    assert_eq!(v.borrow()[i], 1);
                 }
             });
 
@@ -1634,7 +1634,7 @@ mod test_map {
 
             DROP_VECTOR.with(|v| {
                 for i in range(0u, 200) {
-                    assert_eq!(v.borrow().as_slice()[i], 1);
+                    assert_eq!(v.borrow()[i], 1);
                 }
             });
 
@@ -1642,11 +1642,11 @@ mod test_map {
 
             DROP_VECTOR.with(|v| {
                 let nk = range(0u, 100).filter(|&i| {
-                    v.borrow().as_slice()[i] == 1
+                    v.borrow()[i] == 1
                 }).count();
 
                 let nv = range(0u, 100).filter(|&i| {
-                    v.borrow().as_slice()[i+100] == 1
+                    v.borrow()[i+100] == 1
                 }).count();
 
                 assert_eq!(nk, 50);
@@ -1656,7 +1656,7 @@ mod test_map {
 
         DROP_VECTOR.with(|v| {
             for i in range(0u, 200) {
-                assert_eq!(v.borrow().as_slice()[i], 0);
+                assert_eq!(v.borrow()[i], 0);
             }
         });
     }
@@ -1905,8 +1905,8 @@ mod test_map {
 
         let map_str = format!("{}", map);
 
-        assert!(map_str == "{1: 2, 3: 4}".to_string() || map_str == "{3: 4, 1: 2}".to_string());
-        assert_eq!(format!("{}", empty), "{}".to_string());
+        assert!(map_str == "{1: 2, 3: 4}" || map_str == "{3: 4, 1: 2}");
+        assert_eq!(format!("{}", empty), "{}");
     }
 
     #[test]
diff --git a/src/libstd/collections/hash/set.rs b/src/libstd/collections/hash/set.rs
index fd32d207e79..b3ccfdbb47c 100644
--- a/src/libstd/collections/hash/set.rs
+++ b/src/libstd/collections/hash/set.rs
@@ -827,7 +827,7 @@ mod test_set {
         };
 
         let v = hs.into_iter().collect::<Vec<char>>();
-        assert!(['a', 'b'][] == v.as_slice() || ['b', 'a'][] == v.as_slice());
+        assert!(['a', 'b'] == v || ['b', 'a'] == v);
     }
 
     #[test]
@@ -862,7 +862,7 @@ mod test_set {
 
         let set_str = format!("{}", set);
 
-        assert!(set_str == "{1, 2}".to_string() || set_str == "{2, 1}".to_string());
-        assert_eq!(format!("{}", empty), "{}".to_string());
+        assert!(set_str == "{1, 2}" || set_str == "{2, 1}");
+        assert_eq!(format!("{}", empty), "{}");
     }
 }
diff --git a/src/libstd/collections/lru_cache.rs b/src/libstd/collections/lru_cache.rs
index adbc135364b..6caa2f7b4da 100644
--- a/src/libstd/collections/lru_cache.rs
+++ b/src/libstd/collections/lru_cache.rs
@@ -447,15 +447,15 @@ mod tests {
         cache.insert(1, 10);
         cache.insert(2, 20);
         cache.insert(3, 30);
-        assert_eq!(cache.to_string(), "{3: 30, 2: 20, 1: 10}".to_string());
+        assert_eq!(cache.to_string(), "{3: 30, 2: 20, 1: 10}");
         cache.insert(2, 22);
-        assert_eq!(cache.to_string(), "{2: 22, 3: 30, 1: 10}".to_string());
+        assert_eq!(cache.to_string(), "{2: 22, 3: 30, 1: 10}");
         cache.insert(6, 60);
-        assert_eq!(cache.to_string(), "{6: 60, 2: 22, 3: 30}".to_string());
+        assert_eq!(cache.to_string(), "{6: 60, 2: 22, 3: 30}");
         cache.get(&3);
-        assert_eq!(cache.to_string(), "{3: 30, 6: 60, 2: 22}".to_string());
+        assert_eq!(cache.to_string(), "{3: 30, 6: 60, 2: 22}");
         cache.set_capacity(2);
-        assert_eq!(cache.to_string(), "{3: 30, 6: 60}".to_string());
+        assert_eq!(cache.to_string(), "{3: 30, 6: 60}");
     }
 
     #[test]
@@ -466,6 +466,6 @@ mod tests {
         cache.clear();
         assert!(cache.get(&1).is_none());
         assert!(cache.get(&2).is_none());
-        assert_eq!(cache.to_string(), "{}".to_string());
+        assert_eq!(cache.to_string(), "{}");
     }
 }
diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 0b2c6843c96..a8de7356fe7 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -450,30 +450,30 @@ mod test {
         let nread = reader.read(&mut buf);
         assert_eq!(Ok(3), nread);
         let b: &[_] = &[5, 6, 7];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
 
         let mut buf = [0, 0];
         let nread = reader.read(&mut buf);
         assert_eq!(Ok(2), nread);
         let b: &[_] = &[0, 1];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
 
         let mut buf = [0];
         let nread = reader.read(&mut buf);
         assert_eq!(Ok(1), nread);
         let b: &[_] = &[2];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
 
         let mut buf = [0, 0, 0];
         let nread = reader.read(&mut buf);
         assert_eq!(Ok(1), nread);
         let b: &[_] = &[3, 0, 0];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
 
         let nread = reader.read(&mut buf);
         assert_eq!(Ok(1), nread);
         let b: &[_] = &[4, 0, 0];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
 
         assert!(reader.read(&mut buf).is_err());
     }
diff --git a/src/libstd/io/comm_adapters.rs b/src/libstd/io/comm_adapters.rs
index 3de0a7be95e..4ec1a3764db 100644
--- a/src/libstd/io/comm_adapters.rs
+++ b/src/libstd/io/comm_adapters.rs
@@ -176,28 +176,28 @@ mod test {
 
         assert_eq!(Ok(3), reader.read(&mut buf));
         let a: &[u8] = &[1,2,3];
-        assert_eq!(a, buf.as_slice());
+        assert_eq!(a, buf);
 
         assert_eq!(Ok(3), reader.read(&mut buf));
         let a: &[u8] = &[4,5,6];
-        assert_eq!(a, buf.as_slice());
+        assert_eq!(a, buf);
 
         assert_eq!(Ok(2), reader.read(&mut buf));
         let a: &[u8] = &[7,8,6];
-        assert_eq!(a, buf.as_slice());
+        assert_eq!(a, buf);
 
         match reader.read(buf.as_mut_slice()) {
             Ok(..) => panic!(),
             Err(e) => assert_eq!(e.kind, io::EndOfFile),
         }
-        assert_eq!(a, buf.as_slice());
+        assert_eq!(a, buf);
 
         // Ensure it continues to panic in the same way.
         match reader.read(buf.as_mut_slice()) {
             Ok(..) => panic!(),
             Err(e) => assert_eq!(e.kind, io::EndOfFile),
         }
-        assert_eq!(a, buf.as_slice());
+        assert_eq!(a, buf);
     }
 
     #[test]
diff --git a/src/libstd/io/fs.rs b/src/libstd/io/fs.rs
index 86b2dc4d940..5611c6526ad 100644
--- a/src/libstd/io/fs.rs
+++ b/src/libstd/io/fs.rs
@@ -838,7 +838,7 @@ mod test {
     macro_rules! error( ($e:expr, $s:expr) => (
         match $e {
             Ok(_) => panic!("Unexpected success. Should've been: {}", $s),
-            Err(ref err) => assert!(err.to_string().as_slice().contains($s.as_slice()),
+            Err(ref err) => assert!(err.to_string().contains($s.as_slice()),
                                     format!("`{}` did not contain `{}`", err, $s))
         }
     ) )
@@ -996,7 +996,7 @@ mod test {
         }
         check!(unlink(filename));
         let read_str = str::from_utf8(&read_mem).unwrap();
-        assert!(read_str.as_slice() == final_msg.as_slice());
+        assert!(read_str == final_msg);
     }
 
     #[test]
@@ -1104,7 +1104,7 @@ mod test {
             let f = dir.join(format!("{}.txt", n));
             let mut w = check!(File::create(&f));
             let msg_str = format!("{}{}", prefix, n.to_string());
-            let msg = msg_str.as_slice().as_bytes();
+            let msg = msg_str.as_bytes();
             check!(w.write(msg));
         }
         let files = check!(readdir(dir));
diff --git a/src/libstd/io/mem.rs b/src/libstd/io/mem.rs
index 43e02d62b0b..4dc87278e2b 100644
--- a/src/libstd/io/mem.rs
+++ b/src/libstd/io/mem.rs
@@ -444,7 +444,7 @@ mod test {
             assert_eq!(writer.write(&[10]).unwrap_err().kind, io::EndOfFile);
         }
         let b: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
     }
 
     #[test]
@@ -473,7 +473,7 @@ mod test {
 
         }
         let b: &[_] = &[1, 3, 2, 0, 0, 0, 0, 4];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
     }
 
     #[test]
@@ -498,12 +498,12 @@ mod test {
         assert_eq!(reader.read(&mut buf), Ok(1));
         assert_eq!(reader.tell(), Ok(1));
         let b: &[_] = &[0];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
         let mut buf = [0, ..4];
         assert_eq!(reader.read(&mut buf), Ok(4));
         assert_eq!(reader.tell(), Ok(5));
         let b: &[_] = &[1, 2, 3, 4];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
         assert_eq!(reader.read(&mut buf), Ok(3));
         let b: &[_] = &[5, 6, 7];
         assert_eq!(buf[0..3], b);
@@ -551,12 +551,12 @@ mod test {
         assert_eq!(reader.read(&mut buf), Ok(1));
         assert_eq!(reader.tell(), Ok(1));
         let b: &[_] = &[0];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
         let mut buf = [0, ..4];
         assert_eq!(reader.read(&mut buf), Ok(4));
         assert_eq!(reader.tell(), Ok(5));
         let b: &[_] = &[1, 2, 3, 4];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
         assert_eq!(reader.read(&mut buf), Ok(3));
         let b: &[_] = &[5, 6, 7];
         assert_eq!(buf[0..3], b);
@@ -592,7 +592,7 @@ mod test {
         writer.write_line("testing").unwrap();
         writer.write_str("testing").unwrap();
         let mut r = BufReader::new(writer.get_ref());
-        assert_eq!(r.read_to_string().unwrap(), "testingtesting\ntesting".to_string());
+        assert_eq!(r.read_to_string().unwrap(), "testingtesting\ntesting");
     }
 
     #[test]
@@ -602,7 +602,7 @@ mod test {
         writer.write_char('\n').unwrap();
         writer.write_char('ệ').unwrap();
         let mut r = BufReader::new(writer.get_ref());
-        assert_eq!(r.read_to_string().unwrap(), "a\nệ".to_string());
+        assert_eq!(r.read_to_string().unwrap(), "a\nệ");
     }
 
     #[test]
@@ -652,15 +652,15 @@ mod test {
         let mut buf = [0, ..3];
         assert!(r.read_at_least(buf.len(), &mut buf).is_ok());
         let b: &[_] = &[1, 2, 3];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
         assert!(r.read_at_least(0, buf[mut ..0]).is_ok());
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
         assert!(r.read_at_least(buf.len(), &mut buf).is_ok());
         let b: &[_] = &[4, 5, 6];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
         assert!(r.read_at_least(buf.len(), &mut buf).is_err());
         let b: &[_] = &[7, 8, 6];
-        assert_eq!(buf.as_slice(), b);
+        assert_eq!(buf, b);
     }
 
     fn do_bench_mem_writer(b: &mut Bencher, times: uint, len: uint) {
@@ -757,7 +757,7 @@ mod test {
                 for _i in range(0u, 10) {
                     let mut buf = [0 as u8, .. 10];
                     rdr.read(&mut buf).unwrap();
-                    assert_eq!(buf.as_slice(), [5, .. 10].as_slice());
+                    assert_eq!(buf, [5, .. 10]);
                 }
             }
         });
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index e0857fd27ff..d43a7a66c5b 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -240,8 +240,8 @@ use boxed::Box;
 use result::Result;
 use result::Result::{Ok, Err};
 use sys;
-use slice::{AsSlice, SlicePrelude};
-use str::{Str, StrPrelude};
+use slice::SlicePrelude;
+use str::StrPrelude;
 use str;
 use string::String;
 use uint;
@@ -318,7 +318,7 @@ impl IoError {
     pub fn from_errno(errno: uint, detail: bool) -> IoError {
         let mut err = sys::decode_error(errno as i32);
         if detail && err.kind == OtherIoError {
-            err.detail = Some(os::error_string(errno).as_slice().chars()
+            err.detail = Some(os::error_string(errno).chars()
                                  .map(|c| c.to_lowercase()).collect())
         }
         err
@@ -2007,14 +2007,14 @@ mod tests {
     fn test_show() {
         use super::*;
 
-        assert_eq!(format!("{}", USER_READ), "0400".to_string());
-        assert_eq!(format!("{}", USER_FILE), "0644".to_string());
-        assert_eq!(format!("{}", USER_EXEC), "0755".to_string());
-        assert_eq!(format!("{}", USER_RWX),  "0700".to_string());
-        assert_eq!(format!("{}", GROUP_RWX), "0070".to_string());
-        assert_eq!(format!("{}", OTHER_RWX), "0007".to_string());
-        assert_eq!(format!("{}", ALL_PERMISSIONS), "0777".to_string());
-        assert_eq!(format!("{}", USER_READ | USER_WRITE | OTHER_WRITE), "0602".to_string());
+        assert_eq!(format!("{}", USER_READ), "0400");
+        assert_eq!(format!("{}", USER_FILE), "0644");
+        assert_eq!(format!("{}", USER_EXEC), "0755");
+        assert_eq!(format!("{}", USER_RWX),  "0700");
+        assert_eq!(format!("{}", GROUP_RWX), "0070");
+        assert_eq!(format!("{}", OTHER_RWX), "0007");
+        assert_eq!(format!("{}", ALL_PERMISSIONS), "0777");
+        assert_eq!(format!("{}", USER_READ | USER_WRITE | OTHER_WRITE), "0602");
     }
 
     fn _ensure_buffer_is_object_safe<T: Buffer>(x: &T) -> &Buffer {
diff --git a/src/libstd/io/net/ip.rs b/src/libstd/io/net/ip.rs
index 9c0fbbe274b..3fa6f4a6091 100644
--- a/src/libstd/io/net/ip.rs
+++ b/src/libstd/io/net/ip.rs
@@ -641,10 +641,10 @@ mod test {
     #[test]
     fn ipv6_addr_to_string() {
         let a1 = Ipv6Addr(0, 0, 0, 0, 0, 0xffff, 0xc000, 0x280);
-        assert!(a1.to_string() == "::ffff:192.0.2.128".to_string() ||
-                a1.to_string() == "::FFFF:192.0.2.128".to_string());
+        assert!(a1.to_string() == "::ffff:192.0.2.128" ||
+                a1.to_string() == "::FFFF:192.0.2.128");
         assert_eq!(Ipv6Addr(8, 9, 10, 11, 12, 13, 14, 15).to_string(),
-                   "8:9:a:b:c:d:e:f".to_string());
+                   "8:9:a:b:c:d:e:f");
     }
 
     #[test]
diff --git a/src/libstd/io/process.rs b/src/libstd/io/process.rs
index d4d24c1e12f..61ebfb06c71 100644
--- a/src/libstd/io/process.rs
+++ b/src/libstd/io/process.rs
@@ -236,8 +236,8 @@ impl Command {
                 // if the env is currently just inheriting from the parent's,
                 // materialize the parent's env into a hashtable.
                 self.env = Some(os::env_as_bytes().into_iter()
-                                   .map(|(k, v)| (EnvKey(k.as_slice().to_c_str()),
-                                                  v.as_slice().to_c_str()))
+                                   .map(|(k, v)| (EnvKey(k.to_c_str()),
+                                                  v.to_c_str()))
                                    .collect());
                 self.env.as_mut().unwrap()
             }
@@ -810,7 +810,7 @@ mod tests {
     fn stdout_works() {
         let mut cmd = Command::new("echo");
         cmd.arg("foobar").stdout(CreatePipe(false, true));
-        assert_eq!(run_output(cmd), "foobar\n".to_string());
+        assert_eq!(run_output(cmd), "foobar\n");
     }
 
     #[cfg(all(unix, not(target_os="android")))]
@@ -820,7 +820,7 @@ mod tests {
         cmd.arg("-c").arg("pwd")
            .cwd(&Path::new("/"))
            .stdout(CreatePipe(false, true));
-        assert_eq!(run_output(cmd), "/\n".to_string());
+        assert_eq!(run_output(cmd), "/\n");
     }
 
     #[cfg(all(unix, not(target_os="android")))]
@@ -835,7 +835,7 @@ mod tests {
         drop(p.stdin.take());
         let out = read_all(p.stdout.as_mut().unwrap() as &mut Reader);
         assert!(p.wait().unwrap().success());
-        assert_eq!(out, "foobar\n".to_string());
+        assert_eq!(out, "foobar\n");
     }
 
     #[cfg(not(target_os="android"))]
@@ -900,7 +900,7 @@ mod tests {
         let output_str = str::from_utf8(output.as_slice()).unwrap();
 
         assert!(status.success());
-        assert_eq!(output_str.trim().to_string(), "hello".to_string());
+        assert_eq!(output_str.trim().to_string(), "hello");
         // FIXME #7224
         if !running_on_valgrind() {
             assert_eq!(error, Vec::new());
@@ -941,7 +941,7 @@ mod tests {
         let output_str = str::from_utf8(output.as_slice()).unwrap();
 
         assert!(status.success());
-        assert_eq!(output_str.trim().to_string(), "hello".to_string());
+        assert_eq!(output_str.trim().to_string(), "hello");
         // FIXME #7224
         if !running_on_valgrind() {
             assert_eq!(error, Vec::new());
@@ -973,7 +973,7 @@ mod tests {
 
         let output = String::from_utf8(prog.wait_with_output().unwrap().output).unwrap();
         let parent_dir = os::getcwd().unwrap();
-        let child_dir = Path::new(output.as_slice().trim());
+        let child_dir = Path::new(output.trim());
 
         let parent_stat = parent_dir.stat().unwrap();
         let child_stat = child_dir.stat().unwrap();
@@ -991,7 +991,7 @@ mod tests {
         let prog = pwd_cmd().cwd(&parent_dir).spawn().unwrap();
 
         let output = String::from_utf8(prog.wait_with_output().unwrap().output).unwrap();
-        let child_dir = Path::new(output.as_slice().trim());
+        let child_dir = Path::new(output.trim());
 
         let parent_stat = parent_dir.stat().unwrap();
         let child_stat = child_dir.stat().unwrap();
@@ -1031,8 +1031,7 @@ mod tests {
         for &(ref k, ref v) in r.iter() {
             // don't check windows magical empty-named variables
             assert!(k.is_empty() ||
-                    output.as_slice()
-                          .contains(format!("{}={}", *k, *v).as_slice()),
+                    output.contains(format!("{}={}", *k, *v).as_slice()),
                     "output doesn't contain `{}={}`\n{}",
                     k, v, output);
         }
@@ -1050,12 +1049,10 @@ mod tests {
         for &(ref k, ref v) in r.iter() {
             // don't check android RANDOM variables
             if *k != "RANDOM".to_string() {
-                assert!(output.as_slice()
-                              .contains(format!("{}={}",
+                assert!(output.contains(format!("{}={}",
                                                 *k,
                                                 *v).as_slice()) ||
-                        output.as_slice()
-                              .contains(format!("{}=\'{}\'",
+                        output.contains(format!("{}=\'{}\'",
                                                 *k,
                                                 *v).as_slice()));
             }
@@ -1084,7 +1081,7 @@ mod tests {
         let result = prog.wait_with_output().unwrap();
         let output = String::from_utf8_lossy(result.output.as_slice()).into_string();
 
-        assert!(output.as_slice().contains("RUN_TEST_NEW_ENV=123"),
+        assert!(output.contains("RUN_TEST_NEW_ENV=123"),
                 "didn't find RUN_TEST_NEW_ENV inside of:\n\n{}", output);
     }
 
@@ -1094,7 +1091,7 @@ mod tests {
         let result = prog.wait_with_output().unwrap();
         let output = String::from_utf8_lossy(result.output.as_slice()).into_string();
 
-        assert!(output.as_slice().contains("RUN_TEST_NEW_ENV=123"),
+        assert!(output.contains("RUN_TEST_NEW_ENV=123"),
                 "didn't find RUN_TEST_NEW_ENV inside of:\n\n{}", output);
     }
 
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index cf2df0da7fe..48c333f0733 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -528,7 +528,7 @@ mod tests {
             set_stdout(box w);
             println!("hello!");
         });
-        assert_eq!(r.read_to_string().unwrap(), "hello!\n".to_string());
+        assert_eq!(r.read_to_string().unwrap(), "hello!\n");
     }
 
     #[test]
@@ -543,6 +543,6 @@ mod tests {
             panic!("my special message");
         });
         let s = r.read_to_string().unwrap();
-        assert!(s.as_slice().contains("my special message"));
+        assert!(s.contains("my special message"));
     }
 }
diff --git a/src/libstd/num/strconv.rs b/src/libstd/num/strconv.rs
index b42286c0308..c87f40f351b 100644
--- a/src/libstd/num/strconv.rs
+++ b/src/libstd/num/strconv.rs
@@ -428,28 +428,28 @@ mod tests {
     #[test]
     fn test_int_to_str_overflow() {
         let mut i8_val: i8 = 127_i8;
-        assert_eq!(i8_val.to_string(), "127".to_string());
+        assert_eq!(i8_val.to_string(), "127");
 
         i8_val += 1 as i8;
-        assert_eq!(i8_val.to_string(), "-128".to_string());
+        assert_eq!(i8_val.to_string(), "-128");
 
         let mut i16_val: i16 = 32_767_i16;
-        assert_eq!(i16_val.to_string(), "32767".to_string());
+        assert_eq!(i16_val.to_string(), "32767");
 
         i16_val += 1 as i16;
-        assert_eq!(i16_val.to_string(), "-32768".to_string());
+        assert_eq!(i16_val.to_string(), "-32768");
 
         let mut i32_val: i32 = 2_147_483_647_i32;
-        assert_eq!(i32_val.to_string(), "2147483647".to_string());
+        assert_eq!(i32_val.to_string(), "2147483647");
 
         i32_val += 1 as i32;
-        assert_eq!(i32_val.to_string(), "-2147483648".to_string());
+        assert_eq!(i32_val.to_string(), "-2147483648");
 
         let mut i64_val: i64 = 9_223_372_036_854_775_807_i64;
-        assert_eq!(i64_val.to_string(), "9223372036854775807".to_string());
+        assert_eq!(i64_val.to_string(), "9223372036854775807");
 
         i64_val += 1 as i64;
-        assert_eq!(i64_val.to_string(), "-9223372036854775808".to_string());
+        assert_eq!(i64_val.to_string(), "-9223372036854775808");
     }
 }
 
diff --git a/src/libstd/num/uint_macros.rs b/src/libstd/num/uint_macros.rs
index 7b79e535201..0baefb11cf8 100644
--- a/src/libstd/num/uint_macros.rs
+++ b/src/libstd/num/uint_macros.rs
@@ -79,28 +79,28 @@ mod tests {
     #[test]
     fn test_uint_to_str_overflow() {
         let mut u8_val: u8 = 255_u8;
-        assert_eq!(u8_val.to_string(), "255".to_string());
+        assert_eq!(u8_val.to_string(), "255");
 
         u8_val += 1 as u8;
-        assert_eq!(u8_val.to_string(), "0".to_string());
+        assert_eq!(u8_val.to_string(), "0");
 
         let mut u16_val: u16 = 65_535_u16;
-        assert_eq!(u16_val.to_string(), "65535".to_string());
+        assert_eq!(u16_val.to_string(), "65535");
 
         u16_val += 1 as u16;
-        assert_eq!(u16_val.to_string(), "0".to_string());
+        assert_eq!(u16_val.to_string(), "0");
 
         let mut u32_val: u32 = 4_294_967_295_u32;
-        assert_eq!(u32_val.to_string(), "4294967295".to_string());
+        assert_eq!(u32_val.to_string(), "4294967295");
 
         u32_val += 1 as u32;
-        assert_eq!(u32_val.to_string(), "0".to_string());
+        assert_eq!(u32_val.to_string(), "0");
 
         let mut u64_val: u64 = 18_446_744_073_709_551_615_u64;
-        assert_eq!(u64_val.to_string(), "18446744073709551615".to_string());
+        assert_eq!(u64_val.to_string(), "18446744073709551615");
 
         u64_val += 1 as u64;
-        assert_eq!(u64_val.to_string(), "0".to_string());
+        assert_eq!(u64_val.to_string(), "0");
     }
 
     #[test]
diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index ba9bcc05546..2b904acb565 100644
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -316,7 +316,7 @@ pub fn env_as_bytes() -> Vec<(Vec<u8>,Vec<u8>)> {
         fn env_convert(input: Vec<Vec<u8>>) -> Vec<(Vec<u8>, Vec<u8>)> {
             let mut pairs = Vec::new();
             for p in input.iter() {
-                let mut it = p.as_slice().splitn(1, |b| *b == b'=');
+                let mut it = p.splitn(1, |b| *b == b'=');
                 let key = it.next().unwrap().to_vec();
                 let default: &[u8] = &[];
                 let val = it.next().unwrap_or(default).to_vec();
@@ -2069,7 +2069,7 @@ mod tests {
     #[cfg(unix)]
     fn join_paths_unix() {
         fn test_eq(input: &[&str], output: &str) -> bool {
-            join_paths(input).unwrap().as_slice() == output.as_bytes()
+            join_paths(input).unwrap() == output.as_bytes()
         }
 
         assert!(test_eq(&[], ""));
@@ -2084,7 +2084,7 @@ mod tests {
     #[cfg(windows)]
     fn join_paths_windows() {
         fn test_eq(input: &[&str], output: &str) -> bool {
-            join_paths(input).unwrap().as_slice() == output.as_bytes()
+            join_paths(input).unwrap() == output.as_bytes()
         }
 
         assert!(test_eq(&[], ""));
diff --git a/src/libstd/path/mod.rs b/src/libstd/path/mod.rs
index 01b42395471..c7feff8705e 100644
--- a/src/libstd/path/mod.rs
+++ b/src/libstd/path/mod.rs
@@ -942,6 +942,6 @@ mod tests {
 
         let input = r"\foo\bar\baz";
         let path: WindowsPath = WindowsPath::new(input.to_c_str());
-        assert_eq!(path.as_str().unwrap(), input.as_slice());
+        assert_eq!(path.as_str().unwrap(), input);
     }
 }
diff --git a/src/libstd/path/posix.rs b/src/libstd/path/posix.rs
index d6d27daf4ae..ba2c89bf1ce 100644
--- a/src/libstd/path/posix.rs
+++ b/src/libstd/path/posix.rs
@@ -132,7 +132,7 @@ impl GenericPathUnsafe for Path {
     unsafe fn set_filename_unchecked<T: BytesContainer>(&mut self, filename: T) {
         let filename = filename.container_as_bytes();
         match self.sepidx {
-            None if b".." == self.repr.as_slice() => {
+            None if b".." == self.repr => {
                 let mut v = Vec::with_capacity(3 + filename.len());
                 v.push_all(dot_dot_static);
                 v.push(SEP_BYTE);
@@ -159,7 +159,7 @@ impl GenericPathUnsafe for Path {
                 self.repr = Path::normalize(v.as_slice());
             }
         }
-        self.sepidx = self.repr.as_slice().rposition_elem(&SEP_BYTE);
+        self.sepidx = self.repr.rposition_elem(&SEP_BYTE);
     }
 
     unsafe fn push_unchecked<T: BytesContainer>(&mut self, path: T) {
@@ -175,7 +175,7 @@ impl GenericPathUnsafe for Path {
                 // FIXME: this is slow
                 self.repr = Path::normalize(v.as_slice());
             }
-            self.sepidx = self.repr.as_slice().rposition_elem(&SEP_BYTE);
+            self.sepidx = self.repr.rposition_elem(&SEP_BYTE);
         }
     }
 }
@@ -192,7 +192,7 @@ impl GenericPath for Path {
 
     fn dirname<'a>(&'a self) -> &'a [u8] {
         match self.sepidx {
-            None if b".." == self.repr.as_slice() => self.repr.as_slice(),
+            None if b".." == self.repr => self.repr.as_slice(),
             None => dot_static,
             Some(0) => self.repr[..1],
             Some(idx) if self.repr[idx+1..] == b".." => self.repr.as_slice(),
@@ -202,8 +202,8 @@ impl GenericPath for Path {
 
     fn filename<'a>(&'a self) -> Option<&'a [u8]> {
         match self.sepidx {
-            None if b"." == self.repr.as_slice() ||
-                b".." == self.repr.as_slice() => None,
+            None if b"." == self.repr ||
+                b".." == self.repr => None,
             None => Some(self.repr.as_slice()),
             Some(idx) if self.repr[idx+1..] == b".." => None,
             Some(0) if self.repr[1..].is_empty() => None,
@@ -213,20 +213,20 @@ impl GenericPath for Path {
 
     fn pop(&mut self) -> bool {
         match self.sepidx {
-            None if b"." == self.repr.as_slice() => false,
+            None if b"." == self.repr => false,
             None => {
                 self.repr = vec![b'.'];
                 self.sepidx = None;
                 true
             }
-            Some(0) if b"/" == self.repr.as_slice() => false,
+            Some(0) if b"/" == self.repr => false,
             Some(idx) => {
                 if idx == 0 {
                     self.repr.truncate(idx+1);
                 } else {
                     self.repr.truncate(idx);
                 }
-                self.sepidx = self.repr.as_slice().rposition_elem(&SEP_BYTE);
+                self.sepidx = self.repr.rposition_elem(&SEP_BYTE);
                 true
             }
         }
@@ -251,7 +251,7 @@ impl GenericPath for Path {
         } else {
             let mut ita = self.components();
             let mut itb = other.components();
-            if b"." == self.repr.as_slice() {
+            if b"." == self.repr {
                 return match itb.next() {
                     None => true,
                     Some(b) => b != b".."
@@ -306,7 +306,7 @@ impl GenericPath for Path {
                     }
                 }
             }
-            Some(Path::new(comps.as_slice().connect_vec(&SEP_BYTE)))
+            Some(Path::new(comps.connect_vec(&SEP_BYTE)))
         }
     }
 
@@ -407,7 +407,7 @@ impl Path {
 
 // None result means the byte vector didn't need normalizing
 fn normalize_helper<'a>(v: &'a [u8], is_abs: bool) -> Option<Vec<&'a [u8]>> {
-    if is_abs && v.as_slice().is_empty() {
+    if is_abs && v.is_empty() {
         return None;
     }
     let mut comps: Vec<&'a [u8]> = vec![];
@@ -496,8 +496,8 @@ mod tests {
         t!(s: Path::new("foo/../../.."), "../..");
         t!(s: Path::new("foo/../../bar"), "../bar");
 
-        assert_eq!(Path::new(b"foo/bar").into_vec().as_slice(), b"foo/bar");
-        assert_eq!(Path::new(b"/foo/../../bar").into_vec().as_slice(),
+        assert_eq!(Path::new(b"foo/bar").into_vec(), b"foo/bar");
+        assert_eq!(Path::new(b"/foo/../../bar").into_vec(),
                    b"/bar");
 
         let p = Path::new(b"foo/bar\x80");
@@ -537,7 +537,7 @@ mod tests {
             ($path:expr, $disp:ident, $exp:expr) => (
                 {
                     let path = Path::new($path);
-                    assert!(path.$disp().to_string().as_slice() == $exp);
+                    assert!(path.$disp().to_string() == $exp);
                 }
             )
         )
@@ -580,9 +580,9 @@ mod tests {
                 {
                     let path = Path::new($path);
                     let f = format!("{}", path.display());
-                    assert!(f.as_slice() == $exp);
+                    assert!(f == $exp);
                     let f = format!("{}", path.filename_display());
-                    assert!(f.as_slice() == $expf);
+                    assert!(f == $expf);
                 }
             )
         )
@@ -1180,7 +1180,7 @@ mod tests {
                     let path = Path::new($arg);
                     let comps = path.components().collect::<Vec<&[u8]>>();
                     let exp: &[&[u8]] = &[$($exp),*];
-                    assert_eq!(comps.as_slice(), exp);
+                    assert_eq!(comps, exp);
                     let comps = path.components().rev().collect::<Vec<&[u8]>>();
                     let exp = exp.iter().rev().map(|&x|x).collect::<Vec<&[u8]>>();
                     assert_eq!(comps, exp)
@@ -1212,7 +1212,7 @@ mod tests {
                     let path = Path::new($arg);
                     let comps = path.str_components().collect::<Vec<Option<&str>>>();
                     let exp: &[Option<&str>] = &$exp;
-                    assert_eq!(comps.as_slice(), exp);
+                    assert_eq!(comps, exp);
                     let comps = path.str_components().rev().collect::<Vec<Option<&str>>>();
                     let exp = exp.iter().rev().map(|&x|x).collect::<Vec<Option<&str>>>();
                     assert_eq!(comps, exp);
diff --git a/src/libstd/path/windows.rs b/src/libstd/path/windows.rs
index 08e318d32b9..b53e6b2a5e0 100644
--- a/src/libstd/path/windows.rs
+++ b/src/libstd/path/windows.rs
@@ -182,7 +182,7 @@ impl GenericPathUnsafe for Path {
     unsafe fn set_filename_unchecked<T: BytesContainer>(&mut self, filename: T) {
         let filename = filename.container_as_str().unwrap();
         match self.sepidx_or_prefix_len() {
-            None if ".." == self.repr.as_slice() => {
+            None if ".." == self.repr => {
                 let mut s = String::with_capacity(3 + filename.len());
                 s.push_str("..");
                 s.push(SEP);
@@ -192,22 +192,22 @@ impl GenericPathUnsafe for Path {
             None => {
                 self.update_normalized(filename);
             }
-            Some((_,idxa,end)) if self.repr.as_slice().slice(idxa,end) == ".." => {
+            Some((_,idxa,end)) if self.repr.slice(idxa,end) == ".." => {
                 let mut s = String::with_capacity(end + 1 + filename.len());
-                s.push_str(self.repr.as_slice().slice_to(end));
+                s.push_str(self.repr.slice_to(end));
                 s.push(SEP);
                 s.push_str(filename);
                 self.update_normalized(s);
             }
             Some((idxb,idxa,_)) if self.prefix == Some(DiskPrefix) && idxa == self.prefix_len() => {
                 let mut s = String::with_capacity(idxb + filename.len());
-                s.push_str(self.repr.as_slice().slice_to(idxb));
+                s.push_str(self.repr.slice_to(idxb));
                 s.push_str(filename);
                 self.update_normalized(s);
             }
             Some((idxb,_,_)) => {
                 let mut s = String::with_capacity(idxb + 1 + filename.len());
-                s.push_str(self.repr.as_slice().slice_to(idxb));
+                s.push_str(self.repr.slice_to(idxb));
                 s.push(SEP);
                 s.push_str(filename);
                 self.update_normalized(s);
@@ -356,21 +356,21 @@ impl GenericPath for Path {
     /// Always returns a `Some` value.
     fn dirname_str<'a>(&'a self) -> Option<&'a str> {
         Some(match self.sepidx_or_prefix_len() {
-            None if ".." == self.repr.as_slice() => self.repr.as_slice(),
+            None if ".." == self.repr => self.repr.as_slice(),
             None => ".",
-            Some((_,idxa,end)) if self.repr.as_slice().slice(idxa, end) == ".." => {
+            Some((_,idxa,end)) if self.repr.slice(idxa, end) == ".." => {
                 self.repr.as_slice()
             }
-            Some((idxb,_,end)) if self.repr.as_slice().slice(idxb, end) == "\\" => {
+            Some((idxb,_,end)) if self.repr.slice(idxb, end) == "\\" => {
                 self.repr.as_slice()
             }
-            Some((0,idxa,_)) => self.repr.as_slice().slice_to(idxa),
+            Some((0,idxa,_)) => self.repr.slice_to(idxa),
             Some((idxb,idxa,_)) => {
                 match self.prefix {
                     Some(DiskPrefix) | Some(VerbatimDiskPrefix) if idxb == self.prefix_len() => {
-                        self.repr.as_slice().slice_to(idxa)
+                        self.repr.slice_to(idxa)
                     }
-                    _ => self.repr.as_slice().slice_to(idxb)
+                    _ => self.repr.slice_to(idxb)
                 }
             }
         })
@@ -415,14 +415,14 @@ impl GenericPath for Path {
     #[inline]
     fn pop(&mut self) -> bool {
         match self.sepidx_or_prefix_len() {
-            None if "." == self.repr.as_slice() => false,
+            None if "." == self.repr => false,
             None => {
                 self.repr = String::from_str(".");
                 self.sepidx = None;
                 true
             }
             Some((idxb,idxa,end)) if idxb == idxa && idxb == end => false,
-            Some((idxb,_,end)) if self.repr.as_slice().slice(idxb, end) == "\\" => false,
+            Some((idxb,_,end)) if self.repr.slice(idxb, end) == "\\" => false,
             Some((idxb,idxa,_)) => {
                 let trunc = match self.prefix {
                     Some(DiskPrefix) | Some(VerbatimDiskPrefix) | None => {
@@ -442,15 +442,15 @@ impl GenericPath for Path {
         if self.prefix.is_some() {
             Some(Path::new(match self.prefix {
                 Some(DiskPrefix) if self.is_absolute() => {
-                    self.repr.as_slice().slice_to(self.prefix_len()+1)
+                    self.repr.slice_to(self.prefix_len()+1)
                 }
                 Some(VerbatimDiskPrefix) => {
-                    self.repr.as_slice().slice_to(self.prefix_len()+1)
+                    self.repr.slice_to(self.prefix_len()+1)
                 }
-                _ => self.repr.as_slice().slice_to(self.prefix_len())
+                _ => self.repr.slice_to(self.prefix_len())
             }))
         } else if is_vol_relative(self) {
-            Some(Path::new(self.repr.as_slice().slice_to(1)))
+            Some(Path::new(self.repr.slice_to(1)))
         } else {
             None
         }
@@ -469,7 +469,7 @@ impl GenericPath for Path {
     fn is_absolute(&self) -> bool {
         match self.prefix {
             Some(DiskPrefix) => {
-                let rest = self.repr.as_slice().slice_from(self.prefix_len());
+                let rest = self.repr.slice_from(self.prefix_len());
                 rest.len() > 0 && rest.as_bytes()[0] == SEP_BYTE
             }
             Some(_) => true,
@@ -491,7 +491,7 @@ impl GenericPath for Path {
         } else {
             let mut ita = self.str_components().map(|x|x.unwrap());
             let mut itb = other.str_components().map(|x|x.unwrap());
-            if "." == self.repr.as_slice() {
+            if "." == self.repr {
                 return itb.next() != Some("..");
             }
             loop {
@@ -827,7 +827,7 @@ impl Path {
 
     fn update_sepidx(&mut self) {
         let s = if self.has_nonsemantic_trailing_slash() {
-                    self.repr.as_slice().slice_to(self.repr.len()-1)
+                    self.repr.slice_to(self.repr.len()-1)
                 } else { self.repr.as_slice() };
         let idx = s.rfind(if !prefix_is_verbatim(self.prefix) { is_sep }
                           else { is_sep_verbatim });
@@ -923,7 +923,7 @@ pub fn make_non_verbatim(path: &Path) -> Option<Path> {
     }
     // now ensure normalization didn't change anything
     if repr.slice_from(path.prefix_len()) ==
-        new_path.repr.as_slice().slice_from(new_path.prefix_len()) {
+        new_path.repr.slice_from(new_path.prefix_len()) {
         Some(new_path)
     } else {
         None
@@ -1233,8 +1233,8 @@ mod tests {
         t!(s: Path::new("foo\\..\\..\\.."), "..\\..");
         t!(s: Path::new("foo\\..\\..\\bar"), "..\\bar");
 
-        assert_eq!(Path::new(b"foo\\bar").into_vec().as_slice(), b"foo\\bar");
-        assert_eq!(Path::new(b"\\foo\\..\\..\\bar").into_vec().as_slice(), b"\\bar");
+        assert_eq!(Path::new(b"foo\\bar").into_vec(), b"foo\\bar");
+        assert_eq!(Path::new(b"\\foo\\..\\..\\bar").into_vec(), b"\\bar");
 
         t!(s: Path::new("\\\\a"), "\\a");
         t!(s: Path::new("\\\\a\\"), "\\a");
@@ -1322,9 +1322,9 @@ mod tests {
     #[test]
     fn test_display_str() {
         let path = Path::new("foo");
-        assert_eq!(path.display().to_string(), "foo".to_string());
+        assert_eq!(path.display().to_string(), "foo");
         let path = Path::new(b"\\");
-        assert_eq!(path.filename_display().to_string(), "".to_string());
+        assert_eq!(path.filename_display().to_string(), "");
 
         let path = Path::new("foo");
         let mo = path.display().as_cow();
@@ -1341,9 +1341,9 @@ mod tests {
                 {
                     let path = Path::new($path);
                     let f = format!("{}", path.display());
-                    assert_eq!(f.as_slice(), $exp);
+                    assert_eq!(f, $exp);
                     let f = format!("{}", path.filename_display());
-                    assert_eq!(f.as_slice(), $expf);
+                    assert_eq!(f, $expf);
                 }
             )
         )
@@ -2246,7 +2246,7 @@ mod tests {
                     let comps = path.str_components().map(|x|x.unwrap())
                                 .collect::<Vec<&str>>();
                     let exp: &[&str] = &$exp;
-                    assert_eq!(comps.as_slice(), exp);
+                    assert_eq!(comps, exp);
                     let comps = path.str_components().rev().map(|x|x.unwrap())
                                 .collect::<Vec<&str>>();
                     let exp = exp.iter().rev().map(|&x|x).collect::<Vec<&str>>();
@@ -2303,7 +2303,7 @@ mod tests {
                     let path = Path::new($path);
                     let comps = path.components().collect::<Vec<&[u8]>>();
                     let exp: &[&[u8]] = &$exp;
-                    assert_eq!(comps.as_slice(), exp);
+                    assert_eq!(comps, exp);
                     let comps = path.components().rev().collect::<Vec<&[u8]>>();
                     let exp = exp.iter().rev().map(|&x|x).collect::<Vec<&[u8]>>();
                     assert_eq!(comps, exp);
diff --git a/src/libstd/rand/mod.rs b/src/libstd/rand/mod.rs
index 413d9267152..cc3c46f3610 100644
--- a/src/libstd/rand/mod.rs
+++ b/src/libstd/rand/mod.rs
@@ -529,7 +529,7 @@ mod test {
         let mut one = [1i];
         r.shuffle(&mut one);
         let b: &[_] = &[1];
-        assert_eq!(one.as_slice(), b);
+        assert_eq!(one, b);
 
         let mut two = [1i, 2];
         r.shuffle(&mut two);
@@ -538,7 +538,7 @@ mod test {
         let mut x = [1i, 1, 1];
         r.shuffle(&mut x);
         let b: &[_] = &[1, 1, 1];
-        assert_eq!(x.as_slice(), b);
+        assert_eq!(x, b);
     }
 
     #[test]
@@ -548,7 +548,7 @@ mod test {
         let mut v = [1i, 1, 1];
         r.shuffle(&mut v);
         let b: &[_] = &[1, 1, 1];
-        assert_eq!(v.as_slice(), b);
+        assert_eq!(v, b);
         assert_eq!(r.gen_range(0u, 1u), 0u);
     }
 
diff --git a/src/libstd/rt/backtrace.rs b/src/libstd/rt/backtrace.rs
index 3698a91855c..4ac09a071bb 100644
--- a/src/libstd/rt/backtrace.rs
+++ b/src/libstd/rt/backtrace.rs
@@ -1013,7 +1013,7 @@ mod test {
     macro_rules! t( ($a:expr, $b:expr) => ({
         let mut m = Vec::new();
         super::demangle(&mut m, $a).unwrap();
-        assert_eq!(String::from_utf8(m).unwrap(), $b.to_string());
+        assert_eq!(String::from_utf8(m).unwrap(), $b);
     }) )
 
     #[test]
diff --git a/src/libstd/sync/future.rs b/src/libstd/sync/future.rs
index 79e0d487cad..a8c9983e5aa 100644
--- a/src/libstd/sync/future.rs
+++ b/src/libstd/sync/future.rs
@@ -153,7 +153,7 @@ mod test {
     #[test]
     fn test_from_value() {
         let mut f = Future::from_value("snail".to_string());
-        assert_eq!(f.get(), "snail".to_string());
+        assert_eq!(f.get(), "snail");
     }
 
     #[test]
@@ -161,25 +161,25 @@ mod test {
         let (tx, rx) = channel();
         tx.send("whale".to_string());
         let mut f = Future::from_receiver(rx);
-        assert_eq!(f.get(), "whale".to_string());
+        assert_eq!(f.get(), "whale");
     }
 
     #[test]
     fn test_from_fn() {
         let mut f = Future::from_fn(proc() "brail".to_string());
-        assert_eq!(f.get(), "brail".to_string());
+        assert_eq!(f.get(), "brail");
     }
 
     #[test]
     fn test_interface_get() {
         let mut f = Future::from_value("fail".to_string());
-        assert_eq!(f.get(), "fail".to_string());
+        assert_eq!(f.get(), "fail");
     }
 
     #[test]
     fn test_interface_unwrap() {
         let f = Future::from_value("fail".to_string());
-        assert_eq!(f.unwrap(), "fail".to_string());
+        assert_eq!(f.unwrap(), "fail");
     }
 
     #[test]
@@ -191,7 +191,7 @@ mod test {
     #[test]
     fn test_spawn() {
         let mut f = Future::spawn(proc() "bale".to_string());
-        assert_eq!(f.get(), "bale".to_string());
+        assert_eq!(f.get(), "bale");
     }
 
     #[test]
diff --git a/src/libstd/sys/unix/fs.rs b/src/libstd/sys/unix/fs.rs
index a773ef7e317..66f7d85f20d 100644
--- a/src/libstd/sys/unix/fs.rs
+++ b/src/libstd/sys/unix/fs.rs
@@ -201,7 +201,7 @@ pub fn readdir(p: &Path) -> IoResult<Vec<Path>> {
 
     let size = unsafe { rust_dirent_t_size() };
     let mut buf = Vec::<u8>::with_capacity(size as uint);
-    let ptr = buf.as_mut_slice().as_mut_ptr() as *mut dirent_t;
+    let ptr = buf.as_mut_ptr() as *mut dirent_t;
 
     let p = p.to_c_str();
     let dir_ptr = unsafe {opendir(p.as_ptr())};
diff --git a/src/libstd/sys/windows/fs.rs b/src/libstd/sys/windows/fs.rs
index 9402c63dcf5..16779a80185 100644
--- a/src/libstd/sys/windows/fs.rs
+++ b/src/libstd/sys/windows/fs.rs
@@ -376,8 +376,8 @@ pub fn readlink(p: &Path) -> IoResult<Path> {
                                   libc::VOLUME_NAME_DOS)
     });
     let ret = match ret {
-        Some(ref s) if s.as_slice().starts_with(r"\\?\") => { // "
-            Ok(Path::new(s.as_slice().slice_from(4)))
+        Some(ref s) if s.starts_with(r"\\?\") => { // "
+            Ok(Path::new(s.slice_from(4)))
         }
         Some(s) => Ok(Path::new(s)),
         None => Err(super::last_error()),
diff --git a/src/libstd/sys/windows/process.rs b/src/libstd/sys/windows/process.rs
index 78a8e09dac1..02548bedf02 100644
--- a/src/libstd/sys/windows/process.rs
+++ b/src/libstd/sys/windows/process.rs
@@ -223,7 +223,7 @@ impl Process {
 
             with_envp(cfg.env(), |envp| {
                 with_dirp(cfg.cwd(), |dirp| {
-                    let mut cmd_str: Vec<u16> = cmd_str.as_slice().utf16_units().collect();
+                    let mut cmd_str: Vec<u16> = cmd_str.utf16_units().collect();
                     cmd_str.push(0);
                     let created = CreateProcessW(ptr::null(),
                                                  cmd_str.as_mut_ptr(),
@@ -433,7 +433,7 @@ fn with_envp<K, V, T>(env: Option<&collections::HashMap<K, V>>,
                 let kv = format!("{}={}",
                                  pair.ref0().container_as_str().unwrap(),
                                  pair.ref1().container_as_str().unwrap());
-                blk.extend(kv.as_slice().utf16_units());
+                blk.extend(kv.utf16_units());
                 blk.push(0);
             }
 
@@ -484,24 +484,24 @@ mod tests {
 
         assert_eq!(
             test_wrapper("prog", &["aaa", "bbb", "ccc"]),
-            "prog aaa bbb ccc".to_string()
+            "prog aaa bbb ccc"
         );
 
         assert_eq!(
             test_wrapper("C:\\Program Files\\blah\\blah.exe", &["aaa"]),
-            "\"C:\\Program Files\\blah\\blah.exe\" aaa".to_string()
+            "\"C:\\Program Files\\blah\\blah.exe\" aaa"
         );
         assert_eq!(
             test_wrapper("C:\\Program Files\\test", &["aa\"bb"]),
-            "\"C:\\Program Files\\test\" aa\\\"bb".to_string()
+            "\"C:\\Program Files\\test\" aa\\\"bb"
         );
         assert_eq!(
             test_wrapper("echo", &["a b c"]),
-            "echo \"a b c\"".to_string()
+            "echo \"a b c\""
         );
         assert_eq!(
             test_wrapper("\u03c0\u042f\u97f3\u00e6\u221e", &[]),
-            "\u03c0\u042f\u97f3\u00e6\u221e".to_string()
+            "\u03c0\u042f\u97f3\u00e6\u221e"
         );
     }
 }
diff --git a/src/libstd/sys/windows/tty.rs b/src/libstd/sys/windows/tty.rs
index 0e7b06cbb94..51679bb2003 100644
--- a/src/libstd/sys/windows/tty.rs
+++ b/src/libstd/sys/windows/tty.rs
@@ -113,7 +113,7 @@ impl TTY {
     pub fn write(&mut self, buf: &[u8]) -> IoResult<()> {
         let utf16 = match from_utf8(buf) {
             Some(utf8) => {
-                utf8.as_slice().utf16_units().collect::<Vec<u16>>()
+                utf8.utf16_units().collect::<Vec<u16>>()
             }
             None => return Err(invalid_encoding()),
         };
diff --git a/src/libstd/task.rs b/src/libstd/task.rs
index 8b4dbf61c18..c91417e611e 100644
--- a/src/libstd/task.rs
+++ b/src/libstd/task.rs
@@ -55,7 +55,7 @@ use result::Result;
 use rustrt::local::Local;
 use rustrt::task::Task;
 use rustrt::task;
-use str::{Str, SendStr};
+use str::SendStr;
 use string::{String, ToString};
 use sync::Future;
 
@@ -244,7 +244,7 @@ pub fn name() -> Option<String> {
 
     let task = Local::borrow(None::<Task>);
     match task.name {
-        Some(ref name) => Some(name.as_slice().to_string()),
+        Some(ref name) => Some(name.to_string()),
         None => None
     }
 }
@@ -289,21 +289,21 @@ mod test {
     #[test]
     fn test_owned_named_task() {
         TaskBuilder::new().named("ada lovelace".to_string()).try(proc() {
-            assert!(name().unwrap() == "ada lovelace".to_string());
+            assert!(name().unwrap() == "ada lovelace");
         }).map_err(|_| ()).unwrap();
     }
 
     #[test]
     fn test_static_named_task() {
         TaskBuilder::new().named("ada lovelace").try(proc() {
-            assert!(name().unwrap() == "ada lovelace".to_string());
+            assert!(name().unwrap() == "ada lovelace");
         }).map_err(|_| ()).unwrap();
     }
 
     #[test]
     fn test_send_named_task() {
         TaskBuilder::new().named("ada lovelace".into_cow()).try(proc() {
-            assert!(name().unwrap() == "ada lovelace".to_string());
+            assert!(name().unwrap() == "ada lovelace");
         }).map_err(|_| ()).unwrap();
     }
 
@@ -464,7 +464,7 @@ mod test {
             Err(e) => {
                 type T = String;
                 assert!(e.is::<T>());
-                assert_eq!(*e.downcast::<T>().unwrap(), "owned string".to_string());
+                assert_eq!(*e.downcast::<T>().unwrap(), "owned string");
             }
             Ok(()) => panic!()
         }
@@ -511,7 +511,7 @@ mod test {
         assert!(r.is_ok());
 
         let output = reader.read_to_string().unwrap();
-        assert_eq!(output, "Hello, world!".to_string());
+        assert_eq!(output, "Hello, world!");
     }
 
     // NOTE: the corresponding test for stderr is in run-pass/task-stderr, due
diff --git a/src/libstd/time/duration.rs b/src/libstd/time/duration.rs
index 63eb9a98736..86c3a1fdd32 100644
--- a/src/libstd/time/duration.rs
+++ b/src/libstd/time/duration.rs
@@ -540,20 +540,20 @@ mod tests {
 
     #[test]
     fn test_duration_fmt() {
-        assert_eq!(Duration::zero().to_string(), "PT0S".to_string());
-        assert_eq!(Duration::days(42).to_string(), "P42D".to_string());
-        assert_eq!(Duration::days(-42).to_string(), "-P42D".to_string());
-        assert_eq!(Duration::seconds(42).to_string(), "PT42S".to_string());
-        assert_eq!(Duration::milliseconds(42).to_string(), "PT0.042S".to_string());
-        assert_eq!(Duration::microseconds(42).to_string(), "PT0.000042S".to_string());
-        assert_eq!(Duration::nanoseconds(42).to_string(), "PT0.000000042S".to_string());
+        assert_eq!(Duration::zero().to_string(), "PT0S");
+        assert_eq!(Duration::days(42).to_string(), "P42D");
+        assert_eq!(Duration::days(-42).to_string(), "-P42D");
+        assert_eq!(Duration::seconds(42).to_string(), "PT42S");
+        assert_eq!(Duration::milliseconds(42).to_string(), "PT0.042S");
+        assert_eq!(Duration::microseconds(42).to_string(), "PT0.000042S");
+        assert_eq!(Duration::nanoseconds(42).to_string(), "PT0.000000042S");
         assert_eq!((Duration::days(7) + Duration::milliseconds(6543)).to_string(),
-                   "P7DT6.543S".to_string());
-        assert_eq!(Duration::seconds(-86401).to_string(), "-P1DT1S".to_string());
-        assert_eq!(Duration::nanoseconds(-1).to_string(), "-PT0.000000001S".to_string());
+                   "P7DT6.543S");
+        assert_eq!(Duration::seconds(-86401).to_string(), "-P1DT1S");
+        assert_eq!(Duration::nanoseconds(-1).to_string(), "-PT0.000000001S");
 
         // the format specifier should have no effect on `Duration`
         assert_eq!(format!("{:30}", Duration::days(1) + Duration::milliseconds(2345)),
-                   "P1DT2.345S".to_string());
+                   "P1DT2.345S");
     }
 }