auto merge of #15515 : pcwalton/rust/cross-borrowing, r=alexcrichton

except where trait objects are involved.

Part of issue #15349, though I'm leaving it open for trait objects.
Cross borrowing for trait objects remains because it is needed until we
have DST.

This will break code like:

    fn foo(x: &int) { ... }

    let a = box 3i;
    foo(a);

Change this code to:

    fn foo(x: &int) { ... }

    let a = box 3i;
    foo(&*a);

[breaking-change]

r? @alexcrichton

Author: bors

src/doc/guide-lifetimes.md

@@ -67,7 +67,7 @@ Now we can call `compute_distance()`:
 # let on_the_stack :     Point  =     Point{x: 3.0, y: 4.0};
 # let on_the_heap  : Box<Point> = box Point{x: 7.0, y: 9.0};
 # fn compute_distance(p1: &Point, p2: &Point) -> f64 { 0.0 }
-compute_distance(&on_the_stack, on_the_heap);
+compute_distance(&on_the_stack, &*on_the_heap);
 ~~~
 
 Here, the `&` operator takes the address of the variable
@@ -77,10 +77,9 @@ value. We also call this _borrowing_ the local variable
 `on_the_stack`, because we have created an alias: that is, another
 name for the same data.
 
-In the case of `on_the_heap`, however, no explicit action is necessary. 
-The compiler will automatically convert a box point to a reference like &point. 
-This is another form of borrowing; in this case, the contents of the owned box 
-are being lent out.
+Likewise, in the case of `owned_box`,
+the `&` operator is used in conjunction with the `*` operator
+to take a reference to the contents of the box.
 
 Whenever a caller lends data to a callee, there are some limitations on what
 the caller can do with the original. For example, if the contents of a

src/doc/guide-pointers.md

@@ -279,7 +279,7 @@ fn main() {
     let origin =    &Point { x: 0.0, y: 0.0 };
     let p1     = box Point { x: 5.0, y: 3.0 };
 
-    println!("{}", compute_distance(origin, p1));
+    println!("{}", compute_distance(origin, &*p1));
 }
 ~~~
 

src/doc/rust.md

@@ -3243,7 +3243,7 @@ enum List { Nil, Cons(uint, Box<List>) }
 fn is_sorted(list: &List) -> bool {
     match *list {
         Nil | Cons(_, box Nil) => true,
-        Cons(x, ref r @ box Cons(y, _)) => (x <= y) && is_sorted(*r)
+        Cons(x, ref r @ box Cons(y, _)) => (x <= y) && is_sorted(&**r)
     }
 }
 

src/doc/tutorial.md

@@ -1470,7 +1470,7 @@ Now we can call `compute_distance()` in various ways:
 # let on_the_stack :     Point  =     Point { x: 3.0, y: 4.0 };
 # let on_the_heap  : Box<Point> = box Point { x: 7.0, y: 9.0 };
 # fn compute_distance(p1: &Point, p2: &Point) -> f64 { 0.0 }
-compute_distance(&on_the_stack, on_the_heap);
+compute_distance(&on_the_stack, &*on_the_heap);
 ~~~
 
 Here the `&` operator is used to take the address of the variable
@@ -1480,11 +1480,9 @@ reference. We also call this _borrowing_ the local variable
 `on_the_stack`, because we are creating an alias: that is, another
 route to the same data.
 
-In the case of `owned_box`, however, no
-explicit action is necessary. The compiler will automatically convert
-a box `box point` to a reference like
-`&point`. This is another form of borrowing; in this case, the
-contents of the owned box are being lent out.
+Likewise, in the case of `owned_box`,
+the `&` operator is used in conjunction with the `*` operator
+to take a reference to the contents of the box.
 
 Whenever a value is borrowed, there are some limitations on what you
 can do with the original. For example, if the contents of a variable

src/liballoc/boxed.rs

@@ -67,7 +67,7 @@ impl<T:PartialEq> PartialEq for Box<T> {
 impl<T:PartialOrd> PartialOrd for Box<T> {
     #[inline]
     fn partial_cmp(&self, other: &Box<T>) -> Option<Ordering> {
-        (**self).partial_cmp(*other)
+        (**self).partial_cmp(&**other)
     }
     #[inline]
     fn lt(&self, other: &Box<T>) -> bool { *(*self) < *(*other) }
@@ -80,7 +80,9 @@ impl<T:PartialOrd> PartialOrd for Box<T> {
 }
 impl<T: Ord> Ord for Box<T> {
     #[inline]
-    fn cmp(&self, other: &Box<T>) -> Ordering { (**self).cmp(*other) }
+    fn cmp(&self, other: &Box<T>) -> Ordering {
+        (**self).cmp(&**other)
+    }
 }
 impl<T: Eq> Eq for Box<T> {}
 

src/libcollections/treemap.rs

@@ -516,7 +516,7 @@ define_iterator! {
 fn deref<'a, K, V>(node: &'a Option<Box<TreeNode<K, V>>>) -> *const TreeNode<K, V> {
     match *node {
         Some(ref n) => {
-            let n: &TreeNode<K, V> = *n;
+            let n: &TreeNode<K, V> = &**n;
             n as *const TreeNode<K, V>
         }
         None => ptr::null()

src/libregex_macros/lib.rs

@@ -623,15 +623,15 @@ fn parse(cx: &mut ExtCtxt, tts: &[ast::TokenTree]) -> Option<String> {
                 _ => {
                     cx.span_err(entry.span, format!(
                         "expected string literal but got `{}`",
-                        pprust::lit_to_string(lit)).as_slice());
+                        pprust::lit_to_string(&*lit)).as_slice());
                     return None
                 }
             }
         }
         _ => {
             cx.span_err(entry.span, format!(
                 "expected string literal but got `{}`",
-                pprust::expr_to_string(entry)).as_slice());
+                pprust::expr_to_string(&*entry)).as_slice());
             return None
         }
     };

src/librustc/driver/driver.rs

@@ -799,7 +799,7 @@ fn print_flowgraph<W:io::Writer>(variants: Vec<borrowck_dot::Variant>,
     let ty_cx = &analysis.ty_cx;
     let cfg = match code {
         blocks::BlockCode(block) => cfg::CFG::new(ty_cx, &*block),
-        blocks::FnLikeCode(fn_like) => cfg::CFG::new(ty_cx, fn_like.body()),
+        blocks::FnLikeCode(fn_like) => cfg::CFG::new(ty_cx, &*fn_like.body()),
     };
     debug!("cfg: {:?}", cfg);
 

src/librustc/metadata/encoder.rs

@@ -1248,7 +1248,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
                     encode_method_sort(ebml_w, 'p');
                     encode_inlined_item(ecx, ebml_w,
                                         IIMethodRef(def_id, true, &*m));
-                    encode_method_argument_names(ebml_w, m.pe_fn_decl());
+                    encode_method_argument_names(ebml_w, &*m.pe_fn_decl());
                 }
             }
 

src/librustc/metadata/tyencode.rs

@@ -267,7 +267,7 @@ fn enc_sty(w: &mut MemWriter, cx: &ctxt, st: &ty::sty) {
         }
         ty::ty_closure(ref f) => {
             mywrite!(w, "f");
-            enc_closure_ty(w, cx, *f);
+            enc_closure_ty(w, cx, &**f);
         }
         ty::ty_bare_fn(ref f) => {
             mywrite!(w, "F");