Make str indexing generic on SliceIndex.

src/test/ui/index-help.stderr

@@ -1,4 +1,4 @@
-error[E0277]: the trait bound `i32: std::slice::SliceIndex<[{integer}]>` is not satisfied
+error[E0277]: the type `[{integer}]` cannot be indexed by `i32`
   --> $DIR/index-help.rs:3:5
    |
 LL |     x[0i32]; //~ ERROR E0277

src/test/ui/indexing-requires-a-uint.rs

@@ -3,7 +3,7 @@
 
 fn main() {
     fn bar<T>(_: T) {}
-    [0][0u8]; //~ ERROR: the trait bound `u8: std::slice::SliceIndex<[{integer}]>` is not satisfied
+    [0][0u8]; //~ ERROR: the type `[{integer}]` cannot be indexed by `u8`
 
     [0][0]; // should infer to be a usize
 

src/test/ui/indexing-requires-a-uint.stderr

@@ -1,7 +1,7 @@
-error[E0277]: the trait bound `u8: std::slice::SliceIndex<[{integer}]>` is not satisfied
+error[E0277]: the type `[{integer}]` cannot be indexed by `u8`
   --> $DIR/indexing-requires-a-uint.rs:6:5
    |
-LL |     [0][0u8]; //~ ERROR: the trait bound `u8: std::slice::SliceIndex<[{integer}]>` is not satisfied
+LL |     [0][0u8]; //~ ERROR: the type `[{integer}]` cannot be indexed by `u8`
    |     ^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[{integer}]>` is not implemented for `u8`

src/test/ui/integral-indexing.rs

@@ -3,14 +3,14 @@ pub fn main() {
     let s: String = "abcdef".to_string();
     v[3_usize];
     v[3];
-    v[3u8];  //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
-    v[3i8];  //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
-    v[3u32]; //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
-    v[3i32]; //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+    v[3u8];  //~ERROR : the type `[isize]` cannot be indexed by `u8`
+    v[3i8];  //~ERROR : the type `[isize]` cannot be indexed by `i8`
+    v[3u32]; //~ERROR : the type `[isize]` cannot be indexed by `u32`
+    v[3i32]; //~ERROR : the type `[isize]` cannot be indexed by `i32`
     s.as_bytes()[3_usize];
     s.as_bytes()[3];
-    s.as_bytes()[3u8];  //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
-    s.as_bytes()[3i8];  //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
-    s.as_bytes()[3u32]; //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
-    s.as_bytes()[3i32]; //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+    s.as_bytes()[3u8];  //~ERROR : the type `[u8]` cannot be indexed by `u8`
+    s.as_bytes()[3i8];  //~ERROR : the type `[u8]` cannot be indexed by `i8`
+    s.as_bytes()[3u32]; //~ERROR : the type `[u8]` cannot be indexed by `u32`
+    s.as_bytes()[3i32]; //~ERROR : the type `[u8]` cannot be indexed by `i32`
 }

src/test/ui/integral-indexing.stderr

@@ -1,70 +1,70 @@
-error[E0277]: the trait bound `u8: std::slice::SliceIndex<[isize]>` is not satisfied
+error[E0277]: the type `[isize]` cannot be indexed by `u8`
   --> $DIR/integral-indexing.rs:6:5
    |
-LL |     v[3u8];  //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+LL |     v[3u8];  //~ERROR : the type `[isize]` cannot be indexed by `u8`
    |     ^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[isize]>` is not implemented for `u8`
    = note: required because of the requirements on the impl of `std::ops::Index<u8>` for `std::vec::Vec<isize>`
 
-error[E0277]: the trait bound `i8: std::slice::SliceIndex<[isize]>` is not satisfied
+error[E0277]: the type `[isize]` cannot be indexed by `i8`
   --> $DIR/integral-indexing.rs:7:5
    |
-LL |     v[3i8];  //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+LL |     v[3i8];  //~ERROR : the type `[isize]` cannot be indexed by `i8`
    |     ^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[isize]>` is not implemented for `i8`
    = note: required because of the requirements on the impl of `std::ops::Index<i8>` for `std::vec::Vec<isize>`
 
-error[E0277]: the trait bound `u32: std::slice::SliceIndex<[isize]>` is not satisfied
+error[E0277]: the type `[isize]` cannot be indexed by `u32`
   --> $DIR/integral-indexing.rs:8:5
    |
-LL |     v[3u32]; //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+LL |     v[3u32]; //~ERROR : the type `[isize]` cannot be indexed by `u32`
    |     ^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[isize]>` is not implemented for `u32`
    = note: required because of the requirements on the impl of `std::ops::Index<u32>` for `std::vec::Vec<isize>`
 
-error[E0277]: the trait bound `i32: std::slice::SliceIndex<[isize]>` is not satisfied
+error[E0277]: the type `[isize]` cannot be indexed by `i32`
   --> $DIR/integral-indexing.rs:9:5
    |
-LL |     v[3i32]; //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+LL |     v[3i32]; //~ERROR : the type `[isize]` cannot be indexed by `i32`
    |     ^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[isize]>` is not implemented for `i32`
    = note: required because of the requirements on the impl of `std::ops::Index<i32>` for `std::vec::Vec<isize>`
 
-error[E0277]: the trait bound `u8: std::slice::SliceIndex<[u8]>` is not satisfied
+error[E0277]: the type `[u8]` cannot be indexed by `u8`
   --> $DIR/integral-indexing.rs:12:5
    |
-LL |     s.as_bytes()[3u8];  //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+LL |     s.as_bytes()[3u8];  //~ERROR : the type `[u8]` cannot be indexed by `u8`
    |     ^^^^^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[u8]>` is not implemented for `u8`
    = note: required because of the requirements on the impl of `std::ops::Index<u8>` for `[u8]`
 
-error[E0277]: the trait bound `i8: std::slice::SliceIndex<[u8]>` is not satisfied
+error[E0277]: the type `[u8]` cannot be indexed by `i8`
   --> $DIR/integral-indexing.rs:13:5
    |
-LL |     s.as_bytes()[3i8];  //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+LL |     s.as_bytes()[3i8];  //~ERROR : the type `[u8]` cannot be indexed by `i8`
    |     ^^^^^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[u8]>` is not implemented for `i8`
    = note: required because of the requirements on the impl of `std::ops::Index<i8>` for `[u8]`
 
-error[E0277]: the trait bound `u32: std::slice::SliceIndex<[u8]>` is not satisfied
+error[E0277]: the type `[u8]` cannot be indexed by `u32`
   --> $DIR/integral-indexing.rs:14:5
    |
-LL |     s.as_bytes()[3u32]; //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+LL |     s.as_bytes()[3u32]; //~ERROR : the type `[u8]` cannot be indexed by `u32`
    |     ^^^^^^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[u8]>` is not implemented for `u32`
    = note: required because of the requirements on the impl of `std::ops::Index<u32>` for `[u8]`
 
-error[E0277]: the trait bound `i32: std::slice::SliceIndex<[u8]>` is not satisfied
+error[E0277]: the type `[u8]` cannot be indexed by `i32`
   --> $DIR/integral-indexing.rs:15:5
    |
-LL |     s.as_bytes()[3i32]; //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+LL |     s.as_bytes()[3i32]; //~ERROR : the type `[u8]` cannot be indexed by `i32`
    |     ^^^^^^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[u8]>` is not implemented for `i32`

src/test/ui/on-unimplemented/slice-index.stderr

@@ -1,4 +1,4 @@
-error[E0277]: the trait bound `i32: std::slice::SliceIndex<[i32]>` is not satisfied
+error[E0277]: the type `[i32]` cannot be indexed by `i32`
   --> $DIR/slice-index.rs:11:5
    |
 LL |     x[1i32]; //~ ERROR E0277
@@ -7,7 +7,7 @@ LL |     x[1i32]; //~ ERROR E0277
    = help: the trait `std::slice::SliceIndex<[i32]>` is not implemented for `i32`
    = note: required because of the requirements on the impl of `std::ops::Index<i32>` for `[i32]`
 
-error[E0277]: the trait bound `std::ops::RangeTo<i32>: std::slice::SliceIndex<[i32]>` is not satisfied
+error[E0277]: the type `[i32]` cannot be indexed by `std::ops::RangeTo<i32>`
   --> $DIR/slice-index.rs:12:5
    |
 LL |     x[..1i32]; //~ ERROR E0277

src/test/ui/str/str-idx.rs

@@ -1,4 +1,7 @@
 pub fn main() {
     let s: &str = "hello";
-    let c: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
+    let _: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
+    let _ = s.get(4); //~ ERROR the type `str` cannot be indexed by `{integer}`
+    let _ = s.get_unchecked(4); //~ ERROR the type `str` cannot be indexed by `{integer}`
+    let _: u8 = s['c']; //~ ERROR the type `str` cannot be indexed by `char`
 }

src/test/ui/str/str-idx.stderr

@@ -1,13 +1,43 @@
 error[E0277]: the type `str` cannot be indexed by `{integer}`
   --> $DIR/str-idx.rs:3:17
    |
-LL |     let c: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
-   |                 ^^^^ `str` cannot be indexed by `{integer}`
+LL |     let _: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
+   |                 ^^^^ string indices are ranges of `usize`
    |
-   = help: the trait `std::ops::Index<{integer}>` is not implemented for `str`
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
+   = note: you can use `.chars().nth()` or `.bytes().nth()`
+           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+   = note: required because of the requirements on the impl of `std::ops::Index<{integer}>` for `str`
+
+error[E0277]: the type `str` cannot be indexed by `{integer}`
+  --> $DIR/str-idx.rs:4:15
+   |
+LL |     let _ = s.get(4); //~ ERROR the type `str` cannot be indexed by `{integer}`
+   |               ^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
    = note: you can use `.chars().nth()` or `.bytes().nth()`
            see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
 
-error: aborting due to previous error
+error[E0277]: the type `str` cannot be indexed by `{integer}`
+  --> $DIR/str-idx.rs:5:15
+   |
+LL |     let _ = s.get_unchecked(4); //~ ERROR the type `str` cannot be indexed by `{integer}`
+   |               ^^^^^^^^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
+   = note: you can use `.chars().nth()` or `.bytes().nth()`
+           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+
+error[E0277]: the type `str` cannot be indexed by `char`
+  --> $DIR/str-idx.rs:6:17
+   |
+LL |     let _: u8 = s['c']; //~ ERROR the type `str` cannot be indexed by `char`
+   |                 ^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `char`
+   = note: required because of the requirements on the impl of `std::ops::Index<char>` for `str`
+
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0277`.

src/test/ui/str/str-mut-idx.rs

@@ -5,7 +5,13 @@ fn mutate(s: &mut str) {
     //~^ ERROR the size for values of type
     //~| ERROR the size for values of type
     s[1usize] = bot();
-    //~^ ERROR the type `str` cannot be mutably indexed by `usize`
+    //~^ ERROR the type `str` cannot be indexed by `usize`
+    s.get_mut(1);
+    //~^ ERROR the type `str` cannot be indexed by `{integer}`
+    s.get_unchecked_mut(1);
+    //~^ ERROR the type `str` cannot be indexed by `{integer}`
+    s['c'];
+    //~^ ERROR the type `str` cannot be indexed by `char`
 }
 
 pub fn main() {}

src/test/ui/str/str-mut-idx.stderr

@@ -22,16 +22,44 @@ LL |     s[1..2] = bot();
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
    = note: the left-hand-side of an assignment must have a statically known size
 
-error[E0277]: the type `str` cannot be mutably indexed by `usize`
+error[E0277]: the type `str` cannot be indexed by `usize`
   --> $DIR/str-mut-idx.rs:7:5
    |
 LL |     s[1usize] = bot();
-   |     ^^^^^^^^^ `str` cannot be mutably indexed by `usize`
+   |     ^^^^^^^^^ string indices are ranges of `usize`
    |
-   = help: the trait `std::ops::IndexMut<usize>` is not implemented for `str`
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `usize`
+   = note: required because of the requirements on the impl of `std::ops::Index<usize>` for `str`
+
+error[E0277]: the type `str` cannot be indexed by `{integer}`
+  --> $DIR/str-mut-idx.rs:9:7
+   |
+LL |     s.get_mut(1);
+   |       ^^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
    = note: you can use `.chars().nth()` or `.bytes().nth()`
            see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
 
-error: aborting due to 3 previous errors
+error[E0277]: the type `str` cannot be indexed by `{integer}`
+  --> $DIR/str-mut-idx.rs:11:7
+   |
+LL |     s.get_unchecked_mut(1);
+   |       ^^^^^^^^^^^^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
+   = note: you can use `.chars().nth()` or `.bytes().nth()`
+           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+
+error[E0277]: the type `str` cannot be indexed by `char`
+  --> $DIR/str-mut-idx.rs:13:5
+   |
+LL |     s['c'];
+   |     ^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `char`
+   = note: required because of the requirements on the impl of `std::ops::Index<char>` for `str`
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0277`.