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 

4 files changed, 11 insertions, 11 deletions

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()),
         };