librustc (RFC #34): Implement the new `Index` and `IndexMut` traits.

This will break code that used the old `Index` trait. Change this code
to use the new `Index` traits. For reference, here are their signatures:

    pub trait Index<Index,Result> {
        fn index<'a>(&'a self, index: &Index) -> &'a Result;
    }
    pub trait IndexMut<Index,Result> {
        fn index_mut<'a>(&'a mut self, index: &Index) -> &'a mut Result;
    }

Closes #6515.

[breaking-change]

5 files changed, 63 insertions, 29 deletions

diff --git a/src/test/run-pass/issue-11736.rs b/src/test/run-pass/issue-11736.rs
index 255807b4c0e..10d6e0158f6 100644
--- a/src/test/run-pass/issue-11736.rs
+++ b/src/test/run-pass/issue-11736.rs
@@ -16,13 +16,13 @@ use std::collections::Bitv;
 fn main() {
     // Generate sieve of Eratosthenes for n up to 1e6
     let n = 1000000u;
-    let sieve = Bitv::with_capacity(n+1, true);
+    let mut sieve = Bitv::with_capacity(n+1, true);
     let limit: uint = (n as f32).sqrt() as uint;
     for i in range(2, limit+1) {
         if sieve[i] {
             let mut j = 0;
             while i*i + j*i <= n {
-                sieve[i*i+j*i] = false;
+                sieve.set(i*i+j*i, false);
                 j += 1;
             }
         }
diff --git a/src/test/run-pass/issue2378c.rs b/src/test/run-pass/issue2378c.rs
deleted file mode 100644
index c453a538c7e..00000000000
--- a/src/test/run-pass/issue2378c.rs
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// aux-build:issue2378a.rs
-// aux-build:issue2378b.rs
-
-extern crate issue2378a;
-extern crate issue2378b;
-
-use issue2378a::{just};
-use issue2378b::{two_maybes};
-
-pub fn main() {
-    let x = two_maybes{a: just(3i), b: just(5i)};
-    assert_eq!(x[0u], (3, 5));
-}
diff --git a/src/test/run-pass/operator-overloading.rs b/src/test/run-pass/operator-overloading.rs
index 00e19b8481f..a36d8132b26 100644
--- a/src/test/run-pass/operator-overloading.rs
+++ b/src/test/run-pass/operator-overloading.rs
@@ -43,8 +43,12 @@ impl ops::Not<Point> for Point {
 }
 
 impl ops::Index<bool,int> for Point {
-    fn index(&self, x: &bool) -> int {
-        if *x { self.x } else { self.y }
+    fn index<'a>(&'a self, x: &bool) -> &'a int {
+        if *x {
+            &self.x
+        } else {
+            &self.y
+        }
     }
 }
 
diff --git a/src/test/run-pass/overload-index-operator.rs b/src/test/run-pass/overload-index-operator.rs
index de5456ef1c0..6b1ac0b821c 100644
--- a/src/test/run-pass/overload-index-operator.rs
+++ b/src/test/run-pass/overload-index-operator.rs
@@ -31,10 +31,10 @@ impl<K,V> AssociationList<K,V> {
 }
 
 impl<K:PartialEq,V:Clone> Index<K,V> for AssociationList<K,V> {
-    fn index(&self, index: &K) -> V {
+    fn index<'a>(&'a self, index: &K) -> &'a V {
         for pair in self.pairs.iter() {
             if pair.key == *index {
-                return pair.value.clone();
+                return &pair.value
             }
         }
         fail!("No value found for key: {:?}", index);
diff --git a/src/test/run-pass/overloaded-index.rs b/src/test/run-pass/overloaded-index.rs
new file mode 100644
index 00000000000..9d7c068cccd
--- /dev/null
+++ b/src/test/run-pass/overloaded-index.rs
@@ -0,0 +1,53 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct Foo {
+    x: int,
+    y: int,
+}
+
+impl Index<int,int> for Foo {
+    fn index<'a>(&'a self, z: &int) -> &'a int {
+        if *z == 0 {
+            &self.x
+        } else {
+            &self.y
+        }
+    }
+}
+
+impl IndexMut<int,int> for Foo {
+    fn index_mut<'a>(&'a mut self, z: &int) -> &'a mut int {
+        if *z == 0 {
+            &mut self.x
+        } else {
+            &mut self.y
+        }
+    }
+}
+
+fn main() {
+    let mut f = Foo {
+        x: 1,
+        y: 2,
+    };
+    assert_eq!(f[1], 2);
+    f[0] = 3;
+    assert_eq!(f[0], 3);
+    {
+        let p = &mut f[1];
+        *p = 4;
+    }
+    {
+        let p = &f[1];
+        assert_eq!(*p, 4);
+    }
+}
+