Add : Box<_> or ::Box<_> type annotations to various places.

This is the kind of change that one is expected to need to make to
accommodate overloaded-`box`.

----

Note that this is not *all* of the changes necessary to accommodate
Issue 22181.  It is merely the subset of those cases where there was
already a let-binding in place that made it easy to add the necesasry
type ascription.

(For unnamed intermediate `Box` values, one must go down a different
route; `Box::new` is the option that maximizes portability, but has
potential inefficiency depending on whether the call is inlined.)

----

There is one place worth note, `run-pass/coerce-match.rs`, where I
used an ugly form of `Box<_>` type ascription where I would have
preferred to use `Box::new` to accommodate overloaded-`box`.  I
deliberately did not use `Box::new` here, because that is already done
in coerce-match-calls.rs.

----

Precursor for overloaded-`box` and placement-`in`; see Issue 22181.

src/liballoc/arc.rs

@@ -69,6 +69,8 @@
 //! }
 //! ```
 
+use boxed::Box;
+
 use core::prelude::*;
 
 use core::atomic;
@@ -170,7 +172,7 @@ impl<T> Arc<T> {
     pub fn new(data: T) -> Arc<T> {
         // Start the weak pointer count as 1 which is the weak pointer that's
         // held by all the strong pointers (kinda), see std/rc.rs for more info
-        let x = box ArcInner {
+        let x: Box<_> = box ArcInner {
             strong: atomic::AtomicUsize::new(1),
             weak: atomic::AtomicUsize::new(1),
             data: data,

src/liballoc/heap.rs

@@ -387,6 +387,7 @@ mod test {
     extern crate test;
     use self::test::Bencher;
     use core::ptr::PtrExt;
+    use boxed::Box;
     use heap;
 
     #[test]
@@ -404,7 +405,7 @@ mod test {
     #[bench]
     fn alloc_owned_small(b: &mut Bencher) {
         b.iter(|| {
-            box 10
+            let _: Box<_> = box 10;
         })
     }
 }

src/liballoc/lib.rs

@@ -96,9 +96,15 @@ pub mod heap;
 
 // Primitive types using the heaps above
 
+// Need to conditionally define the mod from `boxed.rs` to avoid
+// duplicating the lang-items when building in test cfg; but also need
+// to allow code to have `use boxed::HEAP;`
+// and `use boxed::Box;` declarations.
 #[cfg(not(test))]
 pub mod boxed;
 #[cfg(test)]
+mod boxed { pub use std::boxed::{Box, HEAP}; }
+#[cfg(test)]
 mod boxed_test;
 pub mod arc;
 pub mod rc;

src/liballoc/rc.rs

@@ -795,6 +795,7 @@ impl<T> RcBoxPtr<T> for Weak<T> {
 #[cfg(test)]
 mod tests {
     use super::{Rc, Weak, weak_count, strong_count};
+    use std::boxed::Box;
     use std::cell::RefCell;
     use std::option::Option;
     use std::option::Option::{Some, None};
@@ -826,7 +827,7 @@ mod tests {
 
     #[test]
     fn test_destructor() {
-        let x = Rc::new(box 5);
+        let x: Rc<Box<_>> = Rc::new(box 5);
         assert_eq!(**x, 5);
     }
 

src/libarena/lib.rs

@@ -581,11 +581,11 @@ mod tests {
     #[bench]
     pub fn bench_copy_nonarena(b: &mut Bencher) {
         b.iter(|| {
-            box Point {
+            let _: Box<_> = box Point {
                 x: 1,
                 y: 2,
                 z: 3,
-            }
+            };
         })
     }
 
@@ -634,10 +634,10 @@ mod tests {
     #[bench]
     pub fn bench_noncopy_nonarena(b: &mut Bencher) {
         b.iter(|| {
-            box Noncopy {
+            let _: Box<_> = box Noncopy {
                 string: "hello world".to_string(),
                 array: vec!( 1, 2, 3, 4, 5 ),
-            }
+            };
         })
     }
 

src/libcollections/binary_heap.rs

@@ -790,7 +790,7 @@ mod tests {
 
     #[test]
     fn test_push_unique() {
-        let mut heap = BinaryHeap::from_vec(vec![box 2, box 4, box 9]);
+        let mut heap = BinaryHeap::<Box<_>>::from_vec(vec![box 2, box 4, box 9]);
         assert_eq!(heap.len(), 3);
         assert!(*heap.peek().unwrap() == box 9);
         heap.push(box 11);

src/libcollections/linked_list.rs

@@ -984,7 +984,7 @@ mod tests {
 
     #[test]
     fn test_basic() {
-        let mut m = LinkedList::new();
+        let mut m = LinkedList::<Box<_>>::new();
         assert_eq!(m.pop_front(), None);
         assert_eq!(m.pop_back(), None);
         assert_eq!(m.pop_front(), None);

src/libcollections/slice.rs

@@ -1509,6 +1509,7 @@ fn merge_sort<T, F>(v: &mut [T], mut compare: F) where F: FnMut(&T, &T) -> Order
 
 #[cfg(test)]
 mod tests {
+    use alloc::boxed::Box;
     use core::cmp::Ordering::{Greater, Less, Equal};
     use core::prelude::{Some, None, Clone};
     use core::prelude::{Iterator, IteratorExt};
@@ -1799,7 +1800,7 @@ mod tests {
     #[test]
     fn test_swap_remove_noncopyable() {
         // Tests that we don't accidentally run destructors twice.
-        let mut v = Vec::new();
+        let mut v: Vec<Box<_>> = Vec::new();
         v.push(box 0u8);
         v.push(box 0u8);
         v.push(box 0u8);
@@ -1828,7 +1829,7 @@ mod tests {
 
     #[test]
     fn test_truncate() {
-        let mut v = vec![box 6,box 5,box 4];
+        let mut v: Vec<Box<_>> = vec![box 6,box 5,box 4];
         v.truncate(1);
         let v = v;
         assert_eq!(v.len(), 1);
@@ -1838,7 +1839,7 @@ mod tests {
 
     #[test]
     fn test_clear() {
-        let mut v = vec![box 6,box 5,box 4];
+        let mut v: Vec<Box<_>> = vec![box 6,box 5,box 4];
         v.clear();
         assert_eq!(v.len(), 0);
         // If the unsafe block didn't drop things properly, we blow up here.
@@ -1863,11 +1864,11 @@ mod tests {
 
     #[test]
     fn test_dedup_unique() {
-        let mut v0 = vec![box 1, box 1, box 2, box 3];
+        let mut v0: Vec<Box<_>> = vec![box 1, box 1, box 2, box 3];
         v0.dedup();
-        let mut v1 = vec![box 1, box 2, box 2, box 3];
+        let mut v1: Vec<Box<_>> = vec![box 1, box 2, box 2, box 3];
         v1.dedup();
-        let mut v2 = vec![box 1, box 2, box 3, box 3];
+        let mut v2: Vec<Box<_>> = vec![box 1, box 2, box 3, box 3];
         v2.dedup();
         /*
          * If the boxed pointers were leaked or otherwise misused, valgrind
@@ -1877,11 +1878,11 @@ mod tests {
 
     #[test]
     fn test_dedup_shared() {
-        let mut v0 = vec![box 1, box 1, box 2, box 3];
+        let mut v0: Vec<Box<_>> = vec![box 1, box 1, box 2, box 3];
         v0.dedup();
-        let mut v1 = vec![box 1, box 2, box 2, box 3];
+        let mut v1: Vec<Box<_>> = vec![box 1, box 2, box 2, box 3];
         v1.dedup();
-        let mut v2 = vec![box 1, box 2, box 3, box 3];
+        let mut v2: Vec<Box<_>> = vec![box 1, box 2, box 3, box 3];
         v2.dedup();
         /*
          * If the pointers were leaked or otherwise misused, valgrind and/or
@@ -2254,8 +2255,9 @@ mod tests {
     #[test]
     #[should_fail]
     fn test_permute_fail() {
-        let v = [(box 0, Rc::new(0)), (box 0, Rc::new(0)),
-                 (box 0, Rc::new(0)), (box 0, Rc::new(0))];
+        let v: [(Box<_>, Rc<_>); 4] =
+            [(box 0, Rc::new(0)), (box 0, Rc::new(0)),
+             (box 0, Rc::new(0)), (box 0, Rc::new(0))];
         let mut i = 0;
         for _ in v.permutations() {
             if i == 2 {
@@ -2849,7 +2851,7 @@ mod tests {
 
     #[test]
     fn test_to_vec() {
-        let xs = box [1, 2, 3];
+        let xs: Box<_> = box [1, 2, 3];
         let ys = xs.to_vec();
         assert_eq!(ys, [1, 2, 3]);
     }

src/libcollections/vec.rs

@@ -2130,8 +2130,8 @@ mod tests {
     #[test]
     fn test_clone_from() {
         let mut v = vec!();
-        let three = vec!(box 1, box 2, box 3);
-        let two = vec!(box 4, box 5);
+        let three: Vec<Box<_>> = vec!(box 1, box 2, box 3);
+        let two: Vec<Box<_>> = vec!(box 4, box 5);
         // zero, long
         v.clone_from(&three);
         assert_eq!(v, three);

src/libcollections/vec_map.rs

@@ -1205,7 +1205,7 @@ mod test_map {
 
     #[test]
     fn test_move_iter() {
-        let mut m = VecMap::new();
+        let mut m: VecMap<Box<_>> = VecMap::new();
         m.insert(1, box 2);
         let mut called = false;
         for (k, v) in m {

src/libcoretest/any.rs

@@ -68,7 +68,7 @@ fn any_downcast_ref() {
 #[test]
 fn any_downcast_mut() {
     let mut a = 5_usize;
-    let mut b = box 7_usize;
+    let mut b: Box<_> = box 7_usize;
 
     let a_r = &mut a as &mut Any;
     let tmp: &mut uint = &mut *b;

src/libcoretest/option.rs

@@ -16,7 +16,7 @@ use core::clone::Clone;
 #[test]
 fn test_get_ptr() {
     unsafe {
-        let x = box 0;
+        let x: Box<_> = box 0;
         let addr_x: *const int = mem::transmute(&*x);
         let opt = Some(x);
         let y = opt.unwrap();

src/librustc_back/sha2.rs

@@ -606,7 +606,7 @@ mod tests {
 
         let tests = wikipedia_tests;
 
-        let mut sh = box Sha256::new();
+        let mut sh: Box<_> = box Sha256::new();
 
         test_hash(&mut *sh, &tests);
     }

src/libstd/old_io/net/ip.rs

@@ -323,22 +323,22 @@ impl<'a> Parser<'a> {
     }
 
     fn read_ip_addr(&mut self) -> Option<IpAddr> {
-        let ipv4_addr = |p: &mut Parser| p.read_ipv4_addr();
-        let ipv6_addr = |p: &mut Parser| p.read_ipv6_addr();
-        self.read_or(&mut [box ipv4_addr, box ipv6_addr])
+        let ipv4_addr: Box<_> = box |p: &mut Parser| p.read_ipv4_addr();
+        let ipv6_addr: Box<_> = box |p: &mut Parser| p.read_ipv6_addr();
+        self.read_or(&mut [ipv4_addr, ipv6_addr])
     }
 
     fn read_socket_addr(&mut self) -> Option<SocketAddr> {
         let ip_addr = |p: &mut Parser| {
-            let ipv4_p = |p: &mut Parser| p.read_ip_addr();
-            let ipv6_p = |p: &mut Parser| {
+            let ipv4_p: Box<_> = box |p: &mut Parser| p.read_ip_addr();
+            let ipv6_p: Box<_> = box |p: &mut Parser| {
                 let open_br = |p: &mut Parser| p.read_given_char('[');
                 let ip_addr = |p: &mut Parser| p.read_ipv6_addr();
                 let clos_br = |p: &mut Parser| p.read_given_char(']');
                 p.read_seq_3::<char, IpAddr, char, _, _, _>(open_br, ip_addr, clos_br)
                         .map(|t| match t { (_, ip, _) => ip })
             };
-            p.read_or(&mut [box ipv4_p, box ipv6_p])
+            p.read_or(&mut [ipv4_p, ipv6_p])
         };
         let colon = |p: &mut Parser| p.read_given_char(':');
         let port  = |p: &mut Parser| p.read_number(10, 5, 0x10000).map(|n| n as u16);

src/libstd/sync/mpsc/mod.rs

@@ -1044,13 +1044,13 @@ mod test {
 
     #[test]
     fn drop_full() {
-        let (tx, _rx) = channel();
+        let (tx, _rx) = channel::<Box<int>>();
         tx.send(box 1).unwrap();
     }
 
     #[test]
     fn drop_full_shared() {
-        let (tx, _rx) = channel();
+        let (tx, _rx) = channel::<Box<int>>();
         drop(tx.clone());
         drop(tx.clone());
         tx.send(box 1).unwrap();
@@ -1389,7 +1389,7 @@ mod test {
     #[test]
     fn oneshot_multi_thread_send_recv_stress() {
         for _ in 0..stress_factor() {
-            let (tx, rx) = channel();
+            let (tx, rx) = channel::<Box<int>>();
             let _t = thread::spawn(move|| {
                 tx.send(box 10).unwrap();
             });
@@ -1566,7 +1566,7 @@ mod sync_tests {
 
     #[test]
     fn drop_full() {
-        let (tx, _rx) = sync_channel(1);
+        let (tx, _rx) = sync_channel::<Box<int>>(1);
         tx.send(box 1).unwrap();
     }
 

src/libstd/sync/mpsc/mpsc_queue.rs

@@ -164,7 +164,7 @@ mod tests {
 
     #[test]
     fn test_full() {
-        let q = Queue::new();
+        let q: Queue<Box<_>> = Queue::new();
         q.push(box 1);
         q.push(box 2);
     }

src/libstd/sync/mpsc/spsc_queue.rs

@@ -289,7 +289,7 @@ mod test {
     #[test]
     fn drop_full() {
         unsafe {
-            let q = Queue::new(0);
+            let q: Queue<Box<_>> = Queue::new(0);
             q.push(box 1);
             q.push(box 2);
         }

src/libstd/thread.rs

@@ -804,7 +804,7 @@ mod test {
     fn avoid_copying_the_body<F>(spawnfn: F) where F: FnOnce(Thunk<'static>) {
         let (tx, rx) = channel();
 
-        let x = box 1;
+        let x: Box<_> = box 1;
         let x_in_parent = (&*x) as *const i32 as usize;
 
         spawnfn(Thunk::new(move|| {

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

@@ -146,7 +146,7 @@ impl Table {
     fn search_remainder<C:TableCallback>(item: &mut Entry, key: Code, c: C) {
         match item.next {
             None => {
-                let mut entry = box Entry {
+                let mut entry: Box<_> = box Entry {
                     code: key,
                     count: 0,
                     next: None,
@@ -170,7 +170,7 @@ impl Table {
 
         {
             if self.items[index as usize].is_none() {
-                let mut entry = box Entry {
+                let mut entry: Box<_> = box Entry {
                     code: key,
                     count: 0,
                     next: None,

src/test/bench/sudoku.rs

@@ -124,7 +124,7 @@ impl Sudoku {
     fn next_color(&mut self, row: u8, col: u8, start_color: u8) -> bool {
         if start_color < 10u8 {
             // colors not yet used
-            let mut avail = box Colors::new(start_color);
+            let mut avail: Box<_> = box Colors::new(start_color);
 
             // drop colors already in use in neighbourhood
             self.drop_colors(&mut *avail, row, col);

src/test/compile-fail/borrow-tuple-fields.rs

@@ -16,7 +16,7 @@ struct Foo(Box<isize>, isize);
 struct Bar(isize, isize);
 
 fn main() {
-    let x = (box 1, 2);
+    let x: (Box<_>, _) = (box 1, 2);
     let r = &x.0;
     let y = x; //~ ERROR cannot move out of `x` because it is borrowed
 

src/test/compile-fail/borrowck-bad-nested-calls-free.rs

@@ -23,7 +23,7 @@ fn add(v: &usize, w: usize) -> usize {
 }
 
 fn implicit() {
-    let mut a = box 1;
+    let mut a: Box<_> = box 1;
 
     // Note the danger here:
     //
@@ -36,7 +36,7 @@ fn implicit() {
 }
 
 fn explicit() {
-    let mut a = box 1;
+    let mut a: Box<_> = box 1;
     add(
         &*a,
         rewrite(&mut a)); //~ ERROR cannot borrow

src/test/compile-fail/borrowck-bad-nested-calls-move.rs

@@ -23,7 +23,7 @@ fn add(v: &usize, w: Box<usize>) -> usize {
 }
 
 fn implicit() {
-    let mut a = box 1;
+    let mut a: Box<_> = box 1;
 
     // Note the danger here:
     //
@@ -36,7 +36,7 @@ fn implicit() {
 }
 
 fn explicit() {
-    let mut a = box 1;
+    let mut a: Box<_> = box 1;
     add(
         &*a,
         a); //~ ERROR cannot move

src/test/compile-fail/borrowck-borrow-immut-deref-of-box-as-mut.rs

@@ -18,7 +18,7 @@ impl A {
 }
 
 pub fn main() {
-    let a = box A;
+    let a: Box<_> = box A;
     a.foo();
     //~^ ERROR cannot borrow immutable `Box` content `*a` as mutable
 }

src/test/compile-fail/borrowck-box-insensitivity.rs

@@ -31,100 +31,100 @@ struct D {
 }
 
 fn copy_after_move() {
-    let a = box A { x: box 0, y: 1 };
+    let a: Box<_> = box A { x: box 0, y: 1 };
     let _x = a.x;
     let _y = a.y; //~ ERROR use of moved
     //~^^ NOTE `a` moved here (through moving `a.x`)
 }
 
 fn move_after_move() {
-    let a = box B { x: box 0, y: box 1 };
+    let a: Box<_> = box B { x: box 0, y: box 1 };
     let _x = a.x;
     let _y = a.y; //~ ERROR use of moved
     //~^^ NOTE `a` moved here (through moving `a.x`)
 }
 
 fn borrow_after_move() {
-    let a = box A { x: box 0, y: 1 };
+    let a: Box<_> = box A { x: box 0, y: 1 };
     let _x = a.x;
     let _y = &a.y; //~ ERROR use of moved
     //~^^ NOTE `a` moved here (through moving `a.x`)
 }
 
 fn move_after_borrow() {
-    let a = box B { x: box 0, y: box 1 };
+    let a: Box<_> = box B { x: box 0, y: box 1 };
     let _x = &a.x;
     let _y = a.y; //~ ERROR cannot move
 }
 
 fn copy_after_mut_borrow() {
-    let mut a = box A { x: box 0, y: 1 };
+    let mut a: Box<_> = box A { x: box 0, y: 1 };
     let _x = &mut a.x;
     let _y = a.y; //~ ERROR cannot use
 }
 
 fn move_after_mut_borrow() {
-    let mut a = box B { x: box 0, y: box 1 };
+    let mut a: Box<_> = box B { x: box 0, y: box 1 };
     let _x = &mut a.x;
     let _y = a.y; //~ ERROR cannot move
 }
 
 fn borrow_after_mut_borrow() {
-    let mut a = box A { x: box 0, y: 1 };
+    let mut a: Box<_> = box A { x: box 0, y: 1 };
     let _x = &mut a.x;
     let _y = &a.y; //~ ERROR cannot borrow
 }
 
 fn mut_borrow_after_borrow() {
-    let mut a = box A { x: box 0, y: 1 };
+    let mut a: Box<_> = box A { x: box 0, y: 1 };
     let _x = &a.x;
     let _y = &mut a.y; //~ ERROR cannot borrow
 }
 
 fn copy_after_move_nested() {
-    let a = box C { x: box A { x: box 0, y: 1 }, y: 2 };
+    let a: Box<_> = box C { x: box A { x: box 0, y: 1 }, y: 2 };
     let _x = a.x.x;
     let _y = a.y; //~ ERROR use of collaterally moved
 }
 
 fn move_after_move_nested() {
-    let a = box D { x: box A { x: box 0, y: 1 }, y: box 2 };
+    let a: Box<_> = box D { x: box A { x: box 0, y: 1 }, y: box 2 };
     let _x = a.x.x;
     let _y = a.y; //~ ERROR use of collaterally moved
 }
 
 fn borrow_after_move_nested() {
-    let a = box C { x: box A { x: box 0, y: 1 }, y: 2 };
+    let a: Box<_> = box C { x: box A { x: box 0, y: 1 }, y: 2 };
     let _x = a.x.x;
     let _y = &a.y; //~ ERROR use of collaterally moved
 }
 
 fn move_after_borrow_nested() {
-    let a = box D { x: box A { x: box 0, y: 1 }, y: box 2 };
+    let a: Box<_> = box D { x: box A { x: box 0, y: 1 }, y: box 2 };
     let _x = &a.x.x;
     let _y = a.y; //~ ERROR cannot move
 }
 
 fn copy_after_mut_borrow_nested() {
-    let mut a = box C { x: box A { x: box 0, y: 1 }, y: 2 };
+    let mut a: Box<_> = box C { x: box A { x: box 0, y: 1 }, y: 2 };
     let _x = &mut a.x.x;
     let _y = a.y; //~ ERROR cannot use
 }
 
 fn move_after_mut_borrow_nested() {
-    let mut a = box D { x: box A { x: box 0, y: 1 }, y: box 2 };
+    let mut a: Box<_> = box D { x: box A { x: box 0, y: 1 }, y: box 2 };
     let _x = &mut a.x.x;
     let _y = a.y; //~ ERROR cannot move
 }
 
 fn borrow_after_mut_borrow_nested() {
-    let mut a = box C { x: box A { x: box 0, y: 1 }, y: 2 };
+    let mut a: Box<_> = box C { x: box A { x: box 0, y: 1 }, y: 2 };
     let _x = &mut a.x.x;
     let _y = &a.y; //~ ERROR cannot borrow
 }
 
 fn mut_borrow_after_borrow_nested() {
-    let mut a = box C { x: box A { x: box 0, y: 1 }, y: 2 };
+    let mut a: Box<_> = box C { x: box A { x: box 0, y: 1 }, y: 2 };
     let _x = &a.x.x;
     let _y = &mut a.y; //~ ERROR cannot borrow
 }

src/test/compile-fail/borrowck-closures-mut-and-imm.rs

@@ -52,7 +52,7 @@ fn e() {
 }
 
 fn f() {
-    let mut x = box 3;
+    let mut x: Box<_> = box 3;
     let c1 = || get(&*x);
     *x = 5; //~ ERROR cannot assign
 }
@@ -62,7 +62,7 @@ fn g() {
         f: Box<isize>
     }
 
-    let mut x = box Foo { f: box 3 };
+    let mut x: Box<_> = box Foo { f: box 3 };
     let c1 = || get(&*x.f);
     *x.f = 5; //~ ERROR cannot assign to `*x.f`
 }
@@ -72,7 +72,7 @@ fn h() {
         f: Box<isize>
     }
 
-    let mut x = box Foo { f: box 3 };
+    let mut x: Box<_> = box Foo { f: box 3 };
     let c1 = || get(&*x.f);
     let c2 = || *x.f = 5; //~ ERROR cannot borrow `x` as mutable
 }

src/test/compile-fail/borrowck-closures-two-mut.rs

@@ -50,7 +50,7 @@ fn g() {
         f: Box<isize>
     }
 
-    let mut x = box Foo { f: box 3 };
+    let mut x: Box<_> = box Foo { f: box 3 };
     let c1 = to_fn_mut(|| set(&mut *x.f));
     let c2 = to_fn_mut(|| set(&mut *x.f));
     //~^ ERROR cannot borrow `x` as mutable more than once

src/test/compile-fail/borrowck-closures-use-after-free.rs

@@ -25,7 +25,7 @@ impl Drop for Foo {
 }
 
 fn main() {
-  let mut ptr = box Foo { x: 0 };
+  let mut ptr: Box<_> = box Foo { x: 0 };
   let mut test = |foo: &Foo| {
     ptr = box Foo { x: ptr.x + 1 };
   };

src/test/compile-fail/borrowck-for-loop-correct-cmt-for-pattern.rs

@@ -28,7 +28,7 @@ fn main() {
     for &a in &f.a {  //~ ERROR cannot move out
     }
 
-    let x = Some(box 1);
+    let x: Option<Box<_>> = Some(box 1);
     for &a in x.iter() {    //~ ERROR cannot move out
     }
 }

src/test/compile-fail/borrowck-issue-14498.rs

@@ -18,7 +18,7 @@ struct B<'a> { a: Box<&'a mut isize> }
 
 fn borrow_in_var_from_var() {
     let mut x: isize = 1;
-    let y = box &mut x;
+    let y: Box<_> = box &mut x;
     let p = &y;
     let q = &***p;
     **y = 2; //~ ERROR cannot assign to `**y` because it is borrowed
@@ -28,7 +28,7 @@ fn borrow_in_var_from_var() {
 
 fn borrow_in_var_from_field() {
     let mut x = A { a: 1 };
-    let y = box &mut x.a;
+    let y: Box<_> = box &mut x.a;
     let p = &y;
     let q = &***p;
     **y = 2; //~ ERROR cannot assign to `**y` because it is borrowed

src/test/compile-fail/borrowck-issue-2657-1.rs

@@ -11,7 +11,7 @@
 #![feature(box_syntax)]
 
 fn main() {
-    let x = Some(box 1);
+    let x: Option<Box<_>> = Some(box 1);
     match x {
       Some(ref _y) => {
         let _a = x; //~ ERROR cannot move

src/test/compile-fail/borrowck-issue-2657-2.rs

@@ -11,7 +11,7 @@
 #![feature(box_syntax)]
 
 fn main() {
-    let x = Some(box 1);
+    let x: Option<Box<_>> = Some(box 1);
     match x {
       Some(ref y) => {
         let _b = *y; //~ ERROR cannot move out

src/test/compile-fail/borrowck-lend-flow-if.rs

@@ -30,7 +30,7 @@ fn pre_freeze_cond() {
     // In this instance, the freeze is conditional and starts before
     // the mut borrow.
 
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     let _w;
     if cond() {
         _w = &v;
@@ -42,7 +42,7 @@ fn pre_freeze_else() {
     // In this instance, the freeze and mut borrow are on separate sides
     // of the if.
 
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     let _w;
     if cond() {
         _w = &v;

src/test/compile-fail/borrowck-lend-flow-loop.rs

@@ -28,7 +28,7 @@ fn inc(v: &mut Box<isize>) {
 fn loop_overarching_alias_mut() {
     // In this instance, the borrow encompasses the entire loop.
 
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     let mut x = &mut v;
     **x += 1;
     loop {
@@ -39,7 +39,7 @@ fn loop_overarching_alias_mut() {
 fn block_overarching_alias_mut() {
     // In this instance, the borrow encompasses the entire closure call.
 
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     let mut x = &mut v;
     for _ in 0..3 {
         borrow(&*v); //~ ERROR cannot borrow
@@ -50,8 +50,8 @@ fn block_overarching_alias_mut() {
 fn loop_aliased_mut() {
     // In this instance, the borrow is carried through the loop.
 
-    let mut v = box 3;
-    let mut w = box 4;
+    let mut v: Box<_> = box 3;
+    let mut w: Box<_> = box 4;
     let mut _x = &w;
     loop {
         borrow_mut(&mut *v); //~ ERROR cannot borrow
@@ -62,8 +62,8 @@ fn loop_aliased_mut() {
 fn while_aliased_mut() {
     // In this instance, the borrow is carried through the loop.
 
-    let mut v = box 3;
-    let mut w = box 4;
+    let mut v: Box<_> = box 3;
+    let mut w: Box<_> = box 4;
     let mut _x = &w;
     while cond() {
         borrow_mut(&mut *v); //~ ERROR cannot borrow
@@ -75,8 +75,8 @@ fn while_aliased_mut() {
 fn loop_aliased_mut_break() {
     // In this instance, the borrow is carried through the loop.
 
-    let mut v = box 3;
-    let mut w = box 4;
+    let mut v: Box<_> = box 3;
+    let mut w: Box<_> = box 4;
     let mut _x = &w;
     loop {
         borrow_mut(&mut *v);
@@ -89,8 +89,8 @@ fn loop_aliased_mut_break() {
 fn while_aliased_mut_break() {
     // In this instance, the borrow is carried through the loop.
 
-    let mut v = box 3;
-    let mut w = box 4;
+    let mut v: Box<_> = box 3;
+    let mut w: Box<_> = box 4;
     let mut _x = &w;
     while cond() {
         borrow_mut(&mut *v);
@@ -101,8 +101,8 @@ fn while_aliased_mut_break() {
 }
 
 fn while_aliased_mut_cond(cond: bool, cond2: bool) {
-    let mut v = box 3;
-    let mut w = box 4;
+    let mut v: Box<_> = box 3;
+    let mut w: Box<_> = box 4;
     let mut x = &mut w;
     while cond {
         **x += 1;

src/test/compile-fail/borrowck-lend-flow.rs

@@ -29,7 +29,7 @@ fn inc(v: &mut Box<isize>) {
 fn pre_freeze() {
     // In this instance, the freeze starts before the mut borrow.
 
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     let _w = &v;
     borrow_mut(&mut *v); //~ ERROR cannot borrow
 }
@@ -37,7 +37,7 @@ fn pre_freeze() {
 fn post_freeze() {
     // In this instance, the const alias starts after the borrow.
 
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     borrow_mut(&mut *v);
     let _w = &v;
 }

src/test/compile-fail/borrowck-loan-blocks-move-cc.rs

@@ -17,7 +17,7 @@ fn borrow<F>(v: &isize, f: F) where F: FnOnce(&isize) {
 }
 
 fn box_imm() {
-    let v = box 3;
+    let v: Box<_> = box 3;
     let _w = &v;
     thread::spawn(move|| {
         println!("v={}", *v);
@@ -26,7 +26,7 @@ fn box_imm() {
 }
 
 fn box_imm_explicit() {
-    let v = box 3;
+    let v: Box<_> = box 3;
     let _w = &v;
     thread::spawn(move|| {
         println!("v={}", *v);

src/test/compile-fail/borrowck-loan-blocks-mut-uniq.rs

@@ -15,7 +15,7 @@ fn borrow<F>(v: &isize, f: F) where F: FnOnce(&isize) {
 }
 
 fn box_imm() {
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     borrow(&*v,
            |w| { //~ ERROR cannot borrow `v` as mutable
             v = box 4;

src/test/compile-fail/borrowck-move-by-capture.rs

@@ -14,7 +14,7 @@ fn to_fn_mut<A,F:FnMut<A>>(f: F) -> F { f }
 fn to_fn_once<A,F:FnOnce<A>>(f: F) -> F { f }
 
 pub fn main() {
-    let bar = box 3;
+    let bar: Box<_> = box 3;
     let _g = to_fn_mut(|| {
         let _h = to_fn_once(move || -> isize { *bar }); //~ ERROR cannot move out of
     });

src/test/compile-fail/borrowck-move-from-subpath-of-borrowed-path.rs

@@ -14,7 +14,7 @@
 #![feature(box_syntax)]
 
 fn main() {
-    let a = box box 2;
+    let a: Box<Box<_>> = box box 2;
     let b = &a;
 
     let z = *a; //~ ERROR: cannot move out of `*a` because it is borrowed

src/test/compile-fail/borrowck-move-moved-value-into-closure.rs

@@ -15,7 +15,7 @@ fn call_f<F:FnOnce() -> isize>(f: F) -> isize {
 }
 
 fn main() {
-    let t = box 3;
+    let t: Box<_> = box 3;
 
     call_f(move|| { *t + 1 });
     call_f(move|| { *t + 1 }); //~ ERROR capture of moved value

src/test/compile-fail/borrowck-multiple-captures.rs

@@ -15,9 +15,9 @@ use std::thread;
 fn borrow<T>(_: &T) { }
 
 fn different_vars_after_borrows() {
-    let x1 = box 1;
+    let x1: Box<_> = box 1;
     let p1 = &x1;
-    let x2 = box 2;
+    let x2: Box<_> = box 2;
     let p2 = &x2;
     thread::spawn(move|| {
         drop(x1); //~ ERROR cannot move `x1` into closure because it is borrowed
@@ -28,9 +28,9 @@ fn different_vars_after_borrows() {
 }
 
 fn different_vars_after_moves() {
-    let x1 = box 1;
+    let x1: Box<_> = box 1;
     drop(x1);
-    let x2 = box 2;
+    let x2: Box<_> = box 2;
     drop(x2);
     thread::spawn(move|| {
         drop(x1); //~ ERROR capture of moved value: `x1`
@@ -39,7 +39,7 @@ fn different_vars_after_moves() {
 }
 
 fn same_var_after_borrow() {
-    let x = box 1;
+    let x: Box<_> = box 1;
     let p = &x;
     thread::spawn(move|| {
         drop(x); //~ ERROR cannot move `x` into closure because it is borrowed
@@ -49,7 +49,7 @@ fn same_var_after_borrow() {
 }
 
 fn same_var_after_move() {
-    let x = box 1;
+    let x: Box<_> = box 1;
     drop(x);
     thread::spawn(move|| {
         drop(x); //~ ERROR capture of moved value: `x`

src/test/compile-fail/borrowck-no-cycle-in-exchange-heap.rs

@@ -19,7 +19,7 @@ enum cycle {
     empty
 }
 fn main() {
-    let mut x = box cycle::node(node_ {a: box cycle::empty});
+    let mut x: Box<_> = box cycle::node(node_ {a: box cycle::empty});
     // Create a cycle!
     match *x {
       cycle::node(ref mut y) => {

src/test/compile-fail/borrowck-overloaded-index-2.rs

@@ -25,7 +25,7 @@ impl<T> Index<usize> for MyVec<T> {
 }
 
 fn main() {
-    let v = MyVec { data: vec!(box 1, box 2, box 3) };
+    let v = MyVec::<Box<_>> { data: vec!(box 1, box 2, box 3) };
     let good = &v[0]; // Shouldn't fail here
     let bad = v[0];
     //~^ ERROR cannot move out of indexed content

src/test/compile-fail/borrowck-uniq-via-lend.rs

@@ -13,7 +13,7 @@
 fn borrow(_v: &isize) {}
 
 fn local() {
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     borrow(&*v);
 }
 
@@ -32,27 +32,27 @@ fn local_recs() {
 }
 
 fn aliased_imm() {
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     let _w = &v;
     borrow(&*v);
 }
 
 fn aliased_mut() {
-    let mut v = box 3;
+    let mut v: Box<_> = box 3;
     let _w = &mut v;
     borrow(&*v); //~ ERROR cannot borrow `*v`
 }
 
 fn aliased_other() {
-    let mut v = box 3;
-    let mut w = box 4;
+    let mut v: Box<_> = box 3;
+    let mut w: Box<_> = box 4;
     let _x = &mut w;
     borrow(&*v);
 }
 
 fn aliased_other_reassign() {
-    let mut v = box 3;
-    let mut w = box 4;
+    let mut v: Box<_> = box 3;
+    let mut w: Box<_> = box 4;
     let mut _x = &mut w;
     _x = &mut v;
     borrow(&*v); //~ ERROR cannot borrow `*v`

src/test/compile-fail/issue-10398.rs

@@ -11,7 +11,7 @@
 #![feature(box_syntax)]
 
 fn main() {
-    let x = box 1;
+    let x: Box<_> = box 1;
     let f = move|| {
         let _a = x;
         drop(x);

src/test/compile-fail/issue-11192.rs

@@ -21,7 +21,7 @@ impl Drop for Foo {
 }
 
 fn main() {
-    let mut ptr = box Foo { x: 0 };
+    let mut ptr: Box<_> = box Foo { x: 0 };
     let mut test = |foo: &Foo| {
         println!("access {}", foo.x);
         ptr = box Foo { x: ptr.x + 1 };

src/test/compile-fail/issue-11925.rs

@@ -14,7 +14,7 @@ fn to_fn_once<A,F:FnOnce<A>>(f: F) -> F { f }
 
 fn main() {
     let r = {
-        let x = box 42;
+        let x: Box<_> = box 42;
         let f = to_fn_once(move|| &x); //~ ERROR: `x` does not live long enough
         f()
     };

src/test/compile-fail/issue-12127.rs

@@ -14,7 +14,7 @@ fn to_fn_once<A,F:FnOnce<A>>(f: F) -> F { f }
 fn do_it(x: &isize) { }
 
 fn main() {
-    let x = box 22;
+    let x: Box<_> = box 22;
     let f = to_fn_once(move|| do_it(&*x));
     to_fn_once(move|| {
         f();

src/test/compile-fail/issue-17263.rs

@@ -13,12 +13,12 @@
 struct Foo { a: isize, b: isize }
 
 fn main() {
-    let mut x = box Foo { a: 1, b: 2 };
+    let mut x: Box<_> = box Foo { a: 1, b: 2 };
     let (a, b) = (&mut x.a, &mut x.b);
     //~^ ERROR cannot borrow `x` (here through borrowing `x.b`) as mutable more than once at a time
     //~^^ NOTE previous borrow of `x` occurs here (through borrowing `x.a`)
 
-    let mut foo = box Foo { a: 1, b: 2 };
+    let mut foo: Box<_> = box Foo { a: 1, b: 2 };
     let (c, d) = (&mut foo.a, &foo.b);
     //~^ ERROR cannot borrow `foo` (here through borrowing `foo.b`) as immutable
     //~^^ NOTE previous borrow of `foo` occurs here (through borrowing `foo.a`)

src/test/compile-fail/issue-17913.rs

@@ -16,13 +16,13 @@
 #[cfg(target_pointer_width = "64")]
 fn main() {
     let n = 0_usize;
-    let a = box [&n; 0xF000000000000000_usize];
+    let a: Box<_> = box [&n; 0xF000000000000000_usize];
     println!("{}", a[0xFFFFFF_usize]);
 }
 
 #[cfg(target_pointer_width = "32")]
 fn main() {
     let n = 0_usize;
-    let a = box [&n; 0xFFFFFFFF_usize];
+    let a: Box<_> = box [&n; 0xFFFFFFFF_usize];
     println!("{}", a[0xFFFFFF_usize]);
 }

src/test/compile-fail/kindck-impl-type-params-2.rs

@@ -21,7 +21,7 @@ impl<T:Copy> Foo for T {
 fn take_param<T:Foo>(foo: &T) { }
 
 fn main() {
-    let x = box 3;
+    let x: Box<_> = box 3;
     take_param(&x);
     //~^ ERROR the trait `core::marker::Copy` is not implemented
 }

src/test/compile-fail/kindck-inherited-copy-bound.rs

@@ -24,12 +24,12 @@ impl<T:Copy> Foo for T {
 fn take_param<T:Foo>(foo: &T) { }
 
 fn a() {
-    let x = box 3;
+    let x: Box<_> = box 3;
     take_param(&x); //~ ERROR `core::marker::Copy` is not implemented
 }
 
 fn b() {
-    let x = box 3;
+    let x: Box<_> = box 3;
     let y = &x;
     let z = &x as &Foo; //~ ERROR `core::marker::Copy` is not implemented
 }

src/test/compile-fail/liveness-use-after-move.rs

@@ -11,7 +11,7 @@
 #![feature(box_syntax)]
 
 fn main() {
-    let x = box 5;
+    let x: Box<_> = box 5;
     let y = x;
     println!("{}", *x); //~ ERROR use of moved value: `*x`
     y.clone();

src/test/compile-fail/move-in-guard-1.rs

@@ -11,7 +11,7 @@
 #![feature(box_syntax)]
 
 pub fn main() {
-    let x = box 1;
+    let x: Box<_> = box 1;
 
     let v = (1, 2);
 

src/test/compile-fail/move-in-guard-2.rs

@@ -11,7 +11,7 @@
 #![feature(box_syntax)]
 
 pub fn main() {
-    let x = box 1;
+    let x: Box<_> = box 1;
 
     let v = (1, 2);
 

src/test/compile-fail/move-out-of-tuple-field.rs

@@ -13,7 +13,7 @@
 struct Foo(Box<isize>);
 
 fn main() {
-    let x = (box 1,);
+    let x: (Box<_>,) = (box 1,);
     let y = x.0;
     let z = x.0; //~ ERROR use of moved value: `x.0`
 

src/test/compile-fail/mut-cross-borrowing.rs

@@ -13,7 +13,7 @@
 fn f(_: &mut isize) {}
 
 fn main() {
-    let mut x = box 3;
+    let mut x: Box<_> = box 3;
     f(x)    //~ ERROR mismatched types
 }
 

src/test/compile-fail/static-region-bound.rs

@@ -13,7 +13,7 @@
 fn f<T:'static>(_: T) {}
 
 fn main() {
-    let x = box 3;
+    let x: Box<_> = box 3;
     f(x);
     let x = &3; //~ ERROR borrowed value does not live long enough
     f(x);

src/test/compile-fail/use-after-move-implicity-coerced-object.rs

@@ -34,8 +34,8 @@ impl List {
 }
 
 fn main() {
-    let n = box Number { n: 42 };
-    let mut l = box List { list: Vec::new() };
+    let n: Box<_> = box Number { n: 42 };
+    let mut l: Box<_> = box List { list: Vec::new() };
     l.push(n);
     let x = n.to_string();
     //~^ ERROR: use of moved value: `n`

src/test/debuginfo/borrowed-struct.rs

@@ -78,7 +78,7 @@ fn main() {
     let stack_val_interior_ref_2: &f64 = &stack_val.y;
     let ref_to_unnamed: &SomeStruct = &SomeStruct { x: 11, y: 24.5 };
 
-    let unique_val = box SomeStruct { x: 13, y: 26.5 };
+    let unique_val: Box<_> = box SomeStruct { x: 13, y: 26.5 };
     let unique_val_ref: &SomeStruct = &*unique_val;
     let unique_val_interior_ref_1: &int = &unique_val.x;
     let unique_val_interior_ref_2: &f64 = &unique_val.y;

src/test/debuginfo/boxed-struct.rs

@@ -57,9 +57,9 @@ impl Drop for StructWithDestructor {
 
 fn main() {
 
-    let unique = box StructWithSomePadding { x: 99, y: 999, z: 9999, w: 99999 };
+    let unique: Box<_> = box StructWithSomePadding { x: 99, y: 999, z: 9999, w: 99999 };
 
-    let unique_dtor = box StructWithDestructor { x: 77, y: 777, z: 7777, w: 77777 };
+    let unique_dtor: Box<_> = box StructWithDestructor { x: 77, y: 777, z: 7777, w: 77777 };
     zzz(); // #break
 }
 

src/test/debuginfo/generic-method-on-generic-struct.rs

@@ -142,7 +142,7 @@ fn main() {
     let _ = stack.self_by_ref(-1, 2_u16);
     let _ = stack.self_by_val(-3, -4_i16);
 
-    let owned = box Struct { x: 1234.5f64 };
+    let owned: Box<_> = box Struct { x: 1234.5f64 };
     let _ = owned.self_by_ref(-5, -6_i32);
     let _ = owned.self_by_val(-7, -8_i64);
     let _ = owned.self_owned(-9, -10.5_f32);

src/test/debuginfo/method-on-enum.rs

@@ -144,7 +144,7 @@ fn main() {
     let _ = stack.self_by_ref(-1, -2);
     let _ = stack.self_by_val(-3, -4);
 
-    let owned = box Enum::Variant1{ x: 1799, y: 1799 };
+    let owned: Box<_> = box Enum::Variant1{ x: 1799, y: 1799 };
     let _ = owned.self_by_ref(-5, -6);
     let _ = owned.self_by_val(-7, -8);
     let _ = owned.self_owned(-9, -10);

src/test/debuginfo/method-on-generic-struct.rs

@@ -143,7 +143,7 @@ fn main() {
     let _ = stack.self_by_ref(-1, -2);
     let _ = stack.self_by_val(-3, -4);
 
-    let owned = box Struct { x: 1234.5f64 };
+    let owned: Box<_> = box Struct { x: 1234.5f64 };
     let _ = owned.self_by_ref(-5, -6);
     let _ = owned.self_by_val(-7, -8);
     let _ = owned.self_owned(-9, -10);

src/test/debuginfo/method-on-struct.rs

@@ -143,7 +143,7 @@ fn main() {
     let _ = stack.self_by_ref(-1, -2);
     let _ = stack.self_by_val(-3, -4);
 
-    let owned = box Struct { x: 200 };
+    let owned: Box<_> = box Struct { x: 200 };
     let _ = owned.self_by_ref(-5, -6);
     let _ = owned.self_by_val(-7, -8);
     let _ = owned.self_owned(-9, -10);

src/test/debuginfo/method-on-trait.rs

@@ -149,7 +149,7 @@ fn main() {
     let _ = stack.self_by_ref(-1, -2);
     let _ = stack.self_by_val(-3, -4);
 
-    let owned = box Struct { x: 200 };
+    let owned: Box<_> = box Struct { x: 200 };
     let _ = owned.self_by_ref(-5, -6);
     let _ = owned.self_by_val(-7, -8);
     let _ = owned.self_owned(-9, -10);

src/test/debuginfo/method-on-tuple-struct.rs

@@ -141,7 +141,7 @@ fn main() {
     let _ = stack.self_by_ref(-1, -2);
     let _ = stack.self_by_val(-3, -4);
 
-    let owned = box TupleStruct(200, -200.5);
+    let owned: Box<_> = box TupleStruct(200, -200.5);
     let _ = owned.self_by_ref(-5, -6);
     let _ = owned.self_by_val(-7, -8);
     let _ = owned.self_owned(-9, -10);

src/test/debuginfo/self-in-default-method.rs

@@ -143,7 +143,7 @@ fn main() {
     let _ = stack.self_by_ref(-1, -2);
     let _ = stack.self_by_val(-3, -4);
 
-    let owned = box Struct { x: 200 };
+    let owned: Box<_> = box Struct { x: 200 };
     let _ = owned.self_by_ref(-5, -6);
     let _ = owned.self_by_val(-7, -8);
     let _ = owned.self_owned(-9, -10);

src/test/debuginfo/self-in-generic-default-method.rs

@@ -144,7 +144,7 @@ fn main() {
     let _ = stack.self_by_ref(-1, 2_u16);
     let _ = stack.self_by_val(-3, -4_i16);
 
-    let owned = box Struct { x: 879 };
+    let owned: Box<_> = box Struct { x: 879 };
     let _ = owned.self_by_ref(-5, -6_i32);
     let _ = owned.self_by_val(-7, -8_i64);
     let _ = owned.self_owned(-9, -10.5_f32);

src/test/debuginfo/unique-enum.rs

@@ -67,15 +67,15 @@ fn main() {
     // 0b01111100011111000111110001111100 = 2088533116
     // 0b0111110001111100 = 31868
     // 0b01111100 = 124
-    let the_a = box ABC::TheA { x: 0, y: 8970181431921507452 };
+    let the_a: Box<_> = box ABC::TheA { x: 0, y: 8970181431921507452 };
 
     // 0b0001000100010001000100010001000100010001000100010001000100010001 = 1229782938247303441
     // 0b00010001000100010001000100010001 = 286331153
     // 0b0001000100010001 = 4369
     // 0b00010001 = 17
-    let the_b = box ABC::TheB (0, 286331153, 286331153);
+    let the_b: Box<_> = box ABC::TheB (0, 286331153, 286331153);
 
-    let univariant = box Univariant::TheOnlyCase(123234);
+    let univariant: Box<_> = box Univariant::TheOnlyCase(123234);
 
     zzz(); // #break
 }

src/test/debuginfo/var-captured-in-nested-closure.rs

@@ -98,7 +98,7 @@ fn main() {
     };
 
     let struct_ref = &a_struct;
-    let owned = box 6;
+    let owned: Box<_> = box 6;
 
     let mut closure = || {
         let closure_local = 8;

src/test/debuginfo/var-captured-in-sendable-closure.rs

@@ -58,7 +58,7 @@ fn main() {
         c: 4
     };
 
-    let owned = box 5;
+    let owned: Box<_> = box 5;
 
     let closure = move || {
         zzz(); // #break

src/test/debuginfo/var-captured-in-stack-closure.rs

@@ -90,7 +90,7 @@ fn main() {
     };
 
     let struct_ref = &a_struct;
-    let owned = box 6;
+    let owned: Box<_> = box 6;
 
     {
         let mut first_closure = || {

src/test/run-pass/autoderef-method-on-trait.rs

@@ -20,6 +20,6 @@ impl double for uint {
 }
 
 pub fn main() {
-    let x = box() (box 3_usize as Box<double>);
+    let x: Box<_> = box() (box 3_usize as Box<double>);
     assert_eq!(x.double(), 6_usize);
 }

src/test/run-pass/autoderef-method-priority.rs

@@ -24,6 +24,6 @@ impl double for Box<uint> {
 }
 
 pub fn main() {
-    let x = box 3_usize;
+    let x: Box<_> = box 3_usize;
     assert_eq!(x.double(), 6_usize);
 }

src/test/run-pass/autoderef-method-twice-but-not-thrice.rs

@@ -20,6 +20,6 @@ impl double for Box<uint> {
 }
 
 pub fn main() {
-    let x = box box box box box 3_usize;
+    let x: Box<Box<Box<Box<Box<_>>>>> = box box box box box 3_usize;
     assert_eq!(x.double(), 6_usize);
 }

src/test/run-pass/autoderef-method-twice.rs

@@ -20,6 +20,6 @@ impl double for uint {
 }
 
 pub fn main() {
-    let x = box box 3_usize;
+    let x: Box<Box<_>> = box box 3_usize;
     assert_eq!(x.double(), 6_usize);
 }

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

@@ -20,6 +20,6 @@ impl double for uint {
 }
 
 pub fn main() {
-    let x = box 3_usize;
+    let x: Box<_> = box 3_usize;
     assert_eq!(x.double(), 6_usize);
 }

src/test/run-pass/autoref-intermediate-types-issue-3585.rs

@@ -29,6 +29,6 @@ impl Foo for uint {
 }
 
 pub fn main() {
-    let x = box 3_usize;
+    let x: Box<_> = box 3_usize;
     assert_eq!(x.foo(), "box 3".to_string());
 }

src/test/run-pass/bitv-perf-test.rs

@@ -16,8 +16,8 @@ extern crate collections;
 use std::collections::BitVec;
 
 fn bitv_test() {
-    let mut v1 = box BitVec::from_elem(31, false);
-    let v2 = box BitVec::from_elem(31, true);
+    let mut v1: Box<_> = box BitVec::from_elem(31, false);
+    let v2: Box<_> = box BitVec::from_elem(31, true);
     v1.union(&*v2);
 }
 

src/test/run-pass/borrowck-move-by-capture-ok.rs

@@ -13,7 +13,7 @@
 #![feature(unboxed_closures)]
 
 pub fn main() {
-    let bar = box 3;
+    let bar: Box<_> = box 3;
     let h = || -> int *bar;
     assert_eq!(h(), 3);
 }

src/test/run-pass/borrowck-mut-uniq.rs

@@ -30,7 +30,7 @@ fn iter_ints<F>(x: &Ints, mut f: F) -> bool where F: FnMut(&int) -> bool {
 }
 
 pub fn main() {
-    let mut ints = box Ints {sum: box 0, values: Vec::new()};
+    let mut ints: Box<_> = box Ints {sum: box 0, values: Vec::new()};
     add_int(&mut *ints, 22);
     add_int(&mut *ints, 44);
 

src/test/run-pass/cci_borrow.rs

@@ -17,7 +17,7 @@ extern crate cci_borrow_lib;
 use cci_borrow_lib::foo;
 
 pub fn main() {
-    let p = box 22_usize;
+    let p: Box<_> = box 22_usize;
     let r = foo(&*p);
     println!("r={}", r);
     assert_eq!(r, 22_usize);

src/test/run-pass/cleanup-rvalue-temp-during-incomplete-alloc.rs

@@ -43,7 +43,7 @@ fn get_bar(x: uint) -> Vec<uint> { vec!(x * 2) }
 
 pub fn fails() {
     let x = 2;
-    let mut y = Vec::new();
+    let mut y: Vec<Box<_>> = Vec::new();
     y.push(box Conzabble::Bickwick(do_it(&get_bar(x))));
 }
 

src/test/run-pass/clone-with-exterior.rs

@@ -19,7 +19,7 @@ struct Pair {
 }
 
 pub fn main() {
-    let z = box Pair { a : 10, b : 12};
+    let z: Box<_> = box Pair { a : 10, b : 12};
 
     let _t = Thread::spawn(move|| {
         assert_eq!(z.a, 10);

src/test/run-pass/coerce-match.rs

@@ -14,9 +14,13 @@
 #![feature(box_syntax)]
 
 pub fn main() {
-    let _: Box<[int]> = if true { box [1, 2, 3] } else { box [1] };
+    let _: Box<[int]> =
+        if true { let b: Box<_> = box [1, 2, 3]; b } else { let b: Box<_> = box [1]; b };
 
-    let _: Box<[int]> = match true { true => box [1, 2, 3], false => box [1] };
+    let _: Box<[int]> = match true {
+        true => { let b: Box<_> = box [1, 2, 3]; b }
+        false => { let b: Box<_> = box [1]; b }
+    };
 
     // Check we don't get over-keen at propagating coercions in the case of casts.
     let x = if true { 42 } else { 42u8 } as u16;

src/test/run-pass/crate-method-reexport-grrrrrrr.rs

@@ -22,7 +22,7 @@ extern crate crate_method_reexport_grrrrrrr2;
 pub fn main() {
     use crate_method_reexport_grrrrrrr2::rust::add;
     use crate_method_reexport_grrrrrrr2::rust::cx;
-    let x = box() ();
+    let x: Box<_> = box () ();
     x.cx();
     let y = ();
     y.add("hi".to_string());

src/test/run-pass/deref-lval.rs

@@ -14,7 +14,7 @@
 use std::cell::Cell;
 
 pub fn main() {
-    let x = box Cell::new(5);
+    let x: Box<_> = box Cell::new(5);
     x.set(1000);
     println!("{}", x.get());
 }

src/test/run-pass/explicit-self-generic.rs

@@ -33,6 +33,6 @@ impl<K,V> HashMap<K,V> {
 }
 
 pub fn main() {
-    let mut m = box linear_map::<(),()>();
+    let mut m: Box<_> = box linear_map::<(),()>();
     assert_eq!(m.len(), 0);
 }

src/test/run-pass/explicit-self.rs

@@ -70,7 +70,7 @@ trait Nus { fn f(&self); }
 impl Nus for thing { fn f(&self) {} }
 
 pub fn main() {
-    let y = box thing(A {a: 10});
+    let y: Box<_> = box thing(A {a: 10});
     assert_eq!(y.clone().bar(), 10);
     assert_eq!(y.quux(), 10);
 

src/test/run-pass/expr-block-unique.rs

@@ -12,4 +12,4 @@
 #![allow(unknown_features)]
 #![feature(box_syntax)]
 
-pub fn main() { let x = { box 100 }; assert!((*x == 100)); }
+pub fn main() { let x: Box<_> = { box 100 }; assert!((*x == 100)); }

src/test/run-pass/expr-if-unique.rs

@@ -15,7 +15,7 @@
 
 // Tests for if as expressions returning boxed types
 fn test_box() {
-    let rs = if true { box 100 } else { box 101 };
+    let rs: Box<_> = if true { box 100 } else { box 101 };
     assert_eq!(*rs, 100);
 }
 

src/test/run-pass/expr-match-unique.rs

@@ -13,7 +13,7 @@
 
 // Tests for match as expressions resulting in boxed types
 fn test_box() {
-    let res = match true { true => { box 100 }, _ => panic!() };
+    let res: Box<_> = match true { true => { box 100 }, _ => panic!() };
     assert_eq!(*res, 100);
 }
 

src/test/run-pass/func-arg-incomplete-pattern.rs

@@ -25,7 +25,7 @@ fn foo(Foo {x, ..}: Foo) -> *const uint {
 }
 
 pub fn main() {
-    let obj = box 1;
+    let obj: Box<_> = box 1;
     let objptr: *const uint = &*obj;
     let f = Foo {x: obj, y: box 2};
     let xptr = foo(f);

src/test/run-pass/func-arg-ref-pattern.rs

@@ -28,7 +28,7 @@ fn checkval(box ref x: Box<uint>) -> uint {
 }
 
 pub fn main() {
-    let obj = box 1;
+    let obj: Box<_> = box 1;
     let objptr: *const uint = &*obj;
     let xptr = getaddr(obj);
     assert_eq!(objptr, xptr);

src/test/run-pass/generic-alias-unique.rs

@@ -14,7 +14,7 @@
 fn id<T:Send>(t: T) -> T { return t; }
 
 pub fn main() {
-    let expected = box 100;
+    let expected: Box<_> = box 100;
     let actual = id::<Box<int>>(expected.clone());
     println!("{}", *actual);
     assert_eq!(*expected, *actual);

src/test/run-pass/ifmt.rs

@@ -154,7 +154,7 @@ pub fn main() {
     test_order();
 
     // make sure that format! doesn't move out of local variables
-    let a = box 3;
+    let a: Box<_> = box 3;
     format!("{}", a);
     format!("{}", a);
 

src/test/run-pass/init-res-into-things.rs

@@ -67,7 +67,7 @@ fn test_tup() {
 fn test_unique() {
     let i = &Cell::new(0);
     {
-        let _a = box r(i);
+        let _a: Box<_> = box r(i);
     }
     assert_eq!(i.get(), 1);
 }
@@ -75,7 +75,7 @@ fn test_unique() {
 fn test_unique_rec() {
     let i = &Cell::new(0);
     {
-        let _a = box BoxR {
+        let _a: Box<_> = box BoxR {
             x: r(i)
         };
     }

src/test/run-pass/intrinsic-atomics.rs

@@ -40,7 +40,7 @@ mod rusti {
 
 pub fn main() {
     unsafe {
-        let mut x = box 1;
+        let mut x: Box<_> = box 1;
 
         assert_eq!(rusti::atomic_load(&*x), 1);
         *x = 5;

src/test/run-pass/intrinsic-move-val.rs

@@ -23,7 +23,7 @@ mod rusti {
 
 pub fn main() {
     unsafe {
-        let x = box 1;
+        let x: Box<_> = box 1;
         let mut y = rusti::init();
         let mut z: *const uint = transmute(&x);
         rusti::move_val_init(&mut y, x);