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 

1 files changed, 3 insertions, 3 deletions

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);
     }