Implement automatic overloaded dereference.

Closes #7141.

src/test/run-pass/overloaded-autoderef.rs

@@ -0,0 +1,51 @@
+// 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.
+
+use std::cell::RefCell;
+use std::rc::Rc;
+
+#[deriving(Eq, Show)]
+struct Point {
+    x: int,
+    y: int
+}
+
+pub fn main() {
+    assert_eq!(Rc::new(5u).to_uint(), Some(5));
+    assert_eq!((~&~&Rc::new(~~&~5u)).to_uint(), Some(5));
+    let point = Rc::new(Point {x: 2, y: 4});
+    assert_eq!(point.x, 2);
+    assert_eq!(point.y, 4);
+
+    let i = Rc::new(RefCell::new(2));
+    let i_value = *i.borrow();
+    *i.borrow_mut() = 5;
+    assert_eq!((i_value, *i.borrow()), (2, 5));
+
+    let s = Rc::new(~"foo");
+    assert!(s.equiv(&("foo")));
+    assert_eq!(s.as_slice(), "foo");
+
+    let mut_s = Rc::new(RefCell::new(~"foo"));
+    mut_s.borrow_mut().push_str("bar");
+    // HACK assert_eq! would fail here because it stores the LHS and RHS in two locals.
+    assert!(mut_s.borrow().as_slice() == "foobar");
+    assert!(mut_s.borrow_mut().as_slice() == "foobar");
+
+    let p = Rc::new(RefCell::new(Point {x: 1, y: 2}));
+    p.borrow_mut().x = 3;
+    p.borrow_mut().y += 3;
+    assert_eq!(*p.borrow(), Point {x: 3, y: 5});
+
+    let v = Rc::new(RefCell::new(~[1, 2, 3]));
+    v.borrow_mut()[0] = 3;
+    v.borrow_mut()[1] += 3;
+    assert_eq!((v.borrow()[0], v.borrow()[1], v.borrow()[2]), (3, 5, 3));
+}