rollup merge of #21780: steveklabnik/no_as_slice

Use auto deref instead.

Author: alexcrichton

src/doc/reference.md

@@ -3518,7 +3518,7 @@ An example of each kind:
 ```{rust}
 let vec: Vec<i32> = vec![1, 2, 3];
 let arr: [i32; 3] = [1, 2, 3];
-let s: &[i32] = vec.as_slice();
+let s: &[i32] = &vec;
 ```
 
 As you can see, the `vec!` macro allows you to create a `Vec<T>` easily. The

src/doc/trpl/more-strings.md

@@ -100,7 +100,7 @@ To write a function that's generic over types of strings, use `&str`.
 
 ```
 fn some_string_length(x: &str) -> uint {
-        x.len()
+    x.len()
 }
 
 fn main() {
@@ -110,7 +110,7 @@ fn main() {
 
     let s = "Hello, world".to_string();
 
-    println!("{}", some_string_length(s.as_slice()));
+    println!("{}", some_string_length(&s));
 }
 ```
 

src/doc/trpl/patterns.md

@@ -174,13 +174,13 @@ match origin {
 }
 ```
 
-If you want to match against a slice or array, you can use `[]`:
+If you want to match against a slice or array, you can use `&`:
 
 ```{rust}
 fn main() {
     let v = vec!["match_this", "1"];
 
-    match v.as_slice() {
+    match &v {
         ["match_this", second] => println!("The second element is {}", second),
         _ => {},
     }

src/doc/trpl/plugins.md

@@ -82,7 +82,7 @@ fn expand_rn(cx: &mut ExtCtxt, sp: Span, args: &[TokenTree])
         }
     };
 
-    let mut text = text.as_slice();
+    let mut text = &text;
     let mut total = 0;
     while !text.is_empty() {
         match NUMERALS.iter().find(|&&(rn, _)| text.starts_with(rn)) {

src/doc/trpl/strings.md

@@ -36,36 +36,16 @@ s.push_str(", world.");
 println!("{}", s);
 ```
 
-You can get a `&str` view into a `String` with the `as_slice()` method:
+`String`s will coerece into `&str` with an `&`:
 
-```{rust}
+```
 fn takes_slice(slice: &str) {
     println!("Got: {}", slice);
 }
 
 fn main() {
     let s = "Hello".to_string();
-    takes_slice(s.as_slice());
-}
-```
-
-To compare a String to a constant string, prefer `as_slice()`...
-
-```{rust}
-fn compare(string: String) {
-    if string.as_slice() == "Hello" {
-        println!("yes");
-    }
-}
-```
-
-... over `to_string()`:
-
-```{rust}
-fn compare(string: String) {
-    if string == "Hello".to_string() {
-        println!("yes");
-    }
+    takes_slice(&s);
 }
 ```