auto merge of #15085 : brson/rust/stridx, r=alexcrichton

Being able to index into the bytes of a string encourages
poor UTF-8 hygiene. To get a view of `&[u8]` from either
a `String` or `&str` slice, use the `as_bytes()` method.

Closes #12710.

[breaking-change]

If the diffstat is any indication this shouldn't have a huge impact but it will have some. Most changes in the `str` and `path` module. A lot of the existing usages were in tests where ascii is expected. There are a number of other legit uses where the characters are known to be ascii.

src/test/bench/shootout-k-nucleotide-pipes.rs

@@ -183,7 +183,7 @@ fn main() {
 
        if line.len() == 0u { continue; }
 
-       match (line.as_slice()[0] as char, proc_mode) {
+       match (line.as_bytes()[0] as char, proc_mode) {
 
            // start processing if this is the one
            ('>', false) => {

src/test/compile-fail/integral-indexing.rs

@@ -17,10 +17,10 @@ pub fn main() {
     assert_eq!(v.as_slice()[3u32], 3); //~ ERROR: mismatched types
     assert_eq!(v.as_slice()[3i32], 3); //~ ERROR: mismatched types
     println!("{}", v.as_slice()[3u8]); //~ ERROR: mismatched types
-    assert_eq!(s.as_slice()[3u], 'd' as u8);
-    assert_eq!(s.as_slice()[3u8], 'd' as u8); //~ ERROR: mismatched types
-    assert_eq!(s.as_slice()[3i8], 'd' as u8); //~ ERROR: mismatched types
-    assert_eq!(s.as_slice()[3u32], 'd' as u8); //~ ERROR: mismatched types
-    assert_eq!(s.as_slice()[3i32], 'd' as u8); //~ ERROR: mismatched types
-    println!("{}", s.as_slice()[3u8]); //~ ERROR: mismatched types
+    assert_eq!(s.as_bytes()[3u], 'd' as u8);
+    assert_eq!(s.as_bytes()[3u8], 'd' as u8); //~ ERROR: mismatched types
+    assert_eq!(s.as_bytes()[3i8], 'd' as u8); //~ ERROR: mismatched types
+    assert_eq!(s.as_bytes()[3u32], 'd' as u8); //~ ERROR: mismatched types
+    assert_eq!(s.as_bytes()[3i32], 'd' as u8); //~ ERROR: mismatched types
+    println!("{}", s.as_bytes()[3u8]); //~ ERROR: mismatched types
 }

src/test/compile-fail/str-idx.rs

@@ -11,8 +11,6 @@
 extern crate debug;
 
 pub fn main() {
-    let s = "hello".to_string();
-    let c: u8 = s.as_slice()[4];
-    println!("{:?}", c);
-    assert_eq!(c, 0x6f as u8);
+    let s: &str = "hello";
+    let c: u8 = s[4]; //~ ERROR cannot index a value of type `&str`
 }

src/test/run-fail/str-overrun.rs

@@ -14,5 +14,5 @@ fn main() {
     let s: String = "hello".to_string();
 
     // Bounds-check failure.
-    assert_eq!(s.as_slice()[5], 0x0 as u8);
+    assert_eq!(s.as_bytes()[5], 0x0 as u8);
 }

src/test/run-pass/estr-slice.rs

@@ -17,8 +17,8 @@ pub fn main() {
     println!("{}", x);
     println!("{}", y);
 
-    assert_eq!(x[0], 'h' as u8);
-    assert_eq!(x[4], 'o' as u8);
+    assert_eq!(x.as_bytes()[0], 'h' as u8);
+    assert_eq!(x.as_bytes()[4], 'o' as u8);
 
     let z : &str = "thing";
     assert_eq!(v, x);

src/test/run-pass/estr-uniq.rs

@@ -15,6 +15,6 @@ pub fn main() {
     let _y : String = "there".to_string();
     let mut z = "thing".to_string();
     z = x;
-    assert_eq!(z.as_slice()[0], ('h' as u8));
-    assert_eq!(z.as_slice()[4], ('o' as u8));
+    assert_eq!(z.as_bytes()[0], ('h' as u8));
+    assert_eq!(z.as_bytes()[4], ('o' as u8));
 }

src/test/run-pass/str-concat.rs

@@ -16,5 +16,5 @@ pub fn main() {
     let b: String = "world".to_string();
     let s: String = format!("{}{}", a, b);
     println!("{}", s.clone());
-    assert_eq!(s.as_slice()[9], 'd' as u8);
+    assert_eq!(s.as_bytes()[9], 'd' as u8);
 }

src/test/run-pass/task-comm-16.rs

@@ -39,10 +39,10 @@ fn test_str() {
     let s0 = "test".to_string();
     tx.send(s0);
     let s1 = rx.recv();
-    assert_eq!(s1.as_slice()[0], 't' as u8);
-    assert_eq!(s1.as_slice()[1], 'e' as u8);
-    assert_eq!(s1.as_slice()[2], 's' as u8);
-    assert_eq!(s1.as_slice()[3], 't' as u8);
+    assert_eq!(s1.as_bytes()[0], 't' as u8);
+    assert_eq!(s1.as_bytes()[1], 'e' as u8);
+    assert_eq!(s1.as_bytes()[2], 's' as u8);
+    assert_eq!(s1.as_bytes()[3], 't' as u8);
 }
 
 #[deriving(Show)]

src/test/run-pass/trait-bounds-in-arc.rs

@@ -99,7 +99,7 @@ fn check_legs(arc: Arc<Vec<Box<Pet+Share+Send>>>) {
 fn check_names(arc: Arc<Vec<Box<Pet+Share+Send>>>) {
     for pet in arc.iter() {
         pet.name(|name| {
-            assert!(name[0] == 'a' as u8 && name[1] == 'l' as u8);
+            assert!(name.as_bytes()[0] == 'a' as u8 && name.as_bytes()[1] == 'l' as u8);
         })
     }
 }

src/test/run-pass/utf8.rs

@@ -46,7 +46,7 @@ pub fn main() {
         for ab in a.as_slice().bytes() {
             println!("{}", i);
             println!("{}", ab);
-            let bb: u8 = b.as_slice()[i as uint];
+            let bb: u8 = b.as_bytes()[i as uint];
             println!("{}", bb);
             assert_eq!(ab, bb);
             i += 1;