---

yaml
---
r: 172799
b: refs/heads/try
c: d71a68a
h: refs/heads/master
i:
  172797: 7939c69
  172795: f07bc52
  172791: adbc226
  172783: 38205fc
  172767: 7770fd9
  172735: a96101b
  172671: 39ed06c
  172543: fb12dff
v: v3

Author: bors

[refs]

@@ -2,7 +2,7 @@
 refs/heads/master: 170c4399e614fe599c3d41306b3429ca8b3b68c6
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: 5b3cd3900ceda838f5798c30ab96ceb41f962534
-refs/heads/try: 4c78d2834446426b2dd3cc467f1324dacdc9042e
+refs/heads/try: d71a68ae23773e5faaaf88b68b5963288b2cc5ad
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596

branches/try/src/doc/trpl/closures.md

@@ -110,25 +110,27 @@ passing two variables: one is an i32, and one is a function."
 Next, let's look at how `twice` is defined:
 
 ```{rust,ignore}
-fn twice(x: i32, f: |i32| -> i32) -> i32 {
+fn twice<F: Fn(i32) -> i32>(x: i32, f: F) -> i32 {
 ```
 
 `twice` takes two arguments, `x` and `f`. That's why we called it with two
 arguments. `x` is an `i32`, we've done that a ton of times. `f` is a function,
-though, and that function takes an `i32` and returns an `i32`. Notice
-how the `|i32| -> i32` syntax looks a lot like our definition of `square`
-above, if we added the return type in:
-
-```{rust}
-let square = |&: x: i32| -> i32 { x * x };
-//           |i32|       -> i32
-```
-
-This function takes an `i32` and returns an `i32`.
+though, and that function takes an `i32` and returns an `i32`. This is
+what the requirement `Fn(i32) -> i32` for the type parameter `F` says.
+You might ask yourself: why do we need to introduce a type parameter here?
+That is because in Rust each closure has its own unique type.
+So, not only do closures with different signatures have different types,
+but different closures with the *same* signature have *different* types!
+You can think of it this way: the behaviour of a closure is part of its type.
+And since we want to support many different closures that all take
+an `i32` and return an `i32` we introduced a type parameter that is able
+to represent all these closures. 
 
 This is the most complicated function signature we've seen yet! Give it a read
 a few times until you can see how it works. It takes a teeny bit of practice, and
-then it's easy.
+then it's easy. The good news is that this kind of passing a closure around
+can be very efficient. With all the type information available at compile-time
+the compiler can do wonders.
 
 Finally, `twice` returns an `i32` as well.
 

branches/try/src/doc/trpl/error-handling.md

@@ -1,6 +1,6 @@
 % Error Handling in Rust
 
-> The best-laid plans of mice and men
+> The best-laid plans of mice and men  
 > Often go awry
 >
 > "Tae a Moose", Robert Burns

branches/try/src/libcollections/dlist.rs

@@ -221,9 +221,12 @@ impl<T> DList<T> {
         DList{list_head: None, list_tail: Rawlink::none(), length: 0}
     }
 
-    /// Adds all elements from `other` to the end of the list.
+    /// Moves all elements from `other` to the end of the list.
     ///
-    /// This operation should compute in O(1) time.
+    /// This reuses all the nodes from `other` and moves them into `self`. After
+    /// this operation, `other` becomes empty.
+    ///
+    /// This operation should compute in O(1) time and O(1) memory.
     ///
     /// # Examples
     ///
@@ -237,16 +240,20 @@ impl<T> DList<T> {
     /// b.push_back(3i);
     /// b.push_back(4);
     ///
-    /// a.append(b);
+    /// a.append(&mut b);
     ///
     /// for e in a.iter() {
     ///     println!("{}", e); // prints 1, then 2, then 3, then 4
     /// }
+    /// println!("{}", b.len()); // prints 0
     /// ```
-    #[unstable = "append should be by-mutable-reference"]
-    pub fn append(&mut self, mut other: DList<T>) {
+    pub fn append(&mut self, other: &mut DList<T>) {
         match self.list_tail.resolve() {
-            None => *self = other,
+            None => {
+                self.length = other.length;
+                self.list_head = other.list_head.take();
+                self.list_tail = other.list_tail.take();
+            },
             Some(tail) => {
                 // Carefully empty `other`.
                 let o_tail = other.list_tail.take();
@@ -261,6 +268,7 @@ impl<T> DList<T> {
                 }
             }
         }
+        other.length = 0;
     }
 
     /// Provides a forward iterator.
@@ -404,6 +412,51 @@ impl<T> DList<T> {
     pub fn pop_back(&mut self) -> Option<T> {
         self.pop_back_node().map(|box Node{value, ..}| value)
     }
+
+    /// Splits the list into two at the given index. Returns everything after the given index,
+    /// including the index.
+    ///
+    /// This operation should compute in O(n) time.
+    #[stable]
+    pub fn split_off(&mut self, at: uint) -> DList<T> {
+        let len = self.len();
+        assert!(at < len, "Cannot split off at a nonexistent index");
+        if at == 0 {
+            return mem::replace(self, DList::new());
+        }
+
+        // Below, we iterate towards the `i-1`th node, either from the start or the end,
+        // depending on which would be faster.
+        let mut split_node = if at - 1 <= len - 1 - (at - 1) {
+            let mut iter = self.iter_mut();
+            // instead of skipping using .skip() (which creates a new struct),
+            // we skip manually so we can access the head field without
+            // depending on implementation details of Skip
+            for _ in range(0, at - 1) {
+                iter.next();
+            }
+            iter.head
+        }  else {
+            // better off starting from the end
+            let mut iter = self.iter_mut();
+            for _ in range(0, len - 1 - (at - 1)) {
+                iter.next_back();
+            }
+            iter.tail
+        };
+
+        let mut splitted_list = DList {
+            list_head: None,
+            list_tail: self.list_tail,
+            length: len - at
+        };
+
+        mem::swap(&mut split_node.resolve().unwrap().next, &mut splitted_list.list_head);
+        self.list_tail = split_node;
+        self.length = at;
+
+        splitted_list
+    }
 }
 
 #[unsafe_destructor]
@@ -777,6 +830,108 @@ mod tests {
         v.iter().map(|x| (*x).clone()).collect()
     }
 
+    #[test]
+    fn test_append() {
+        // Empty to empty
+        {
+            let mut m: DList<int> = DList::new();
+            let mut n = DList::new();
+            m.append(&mut n);
+            check_links(&m);
+            assert_eq!(m.len(), 0);
+            assert_eq!(n.len(), 0);
+        }
+        // Non-empty to empty
+        {
+            let mut m = DList::new();
+            let mut n = DList::new();
+            n.push_back(2i);
+            m.append(&mut n);
+            check_links(&m);
+            assert_eq!(m.len(), 1);
+            assert_eq!(m.pop_back(), Some(2));
+            assert_eq!(n.len(), 0);
+            check_links(&m);
+        }
+        // Empty to non-empty
+        {
+            let mut m = DList::new();
+            let mut n = DList::new();
+            m.push_back(2i);
+            m.append(&mut n);
+            check_links(&m);
+            assert_eq!(m.len(), 1);
+            assert_eq!(m.pop_back(), Some(2));
+            check_links(&m);
+        }
+
+        // Non-empty to non-empty
+        let v = vec![1i,2,3,4,5];
+        let u = vec![9i,8,1,2,3,4,5];
+        let mut m = list_from(v.as_slice());
+        let mut n = list_from(u.as_slice());
+        m.append(&mut n);
+        check_links(&m);
+        let mut sum = v;
+        sum.push_all(u.as_slice());
+        assert_eq!(sum.len(), m.len());
+        for elt in sum.into_iter() {
+            assert_eq!(m.pop_front(), Some(elt))
+        }
+        assert_eq!(n.len(), 0);
+        // let's make sure it's working properly, since we
+        // did some direct changes to private members
+        n.push_back(3);
+        assert_eq!(n.len(), 1);
+        assert_eq!(n.pop_front(), Some(3));
+        check_links(&n);
+    }
+
+    #[test]
+    fn test_split_off() {
+        // singleton
+        {
+            let mut m = DList::new();
+            m.push_back(1i);
+
+            let p = m.split_off(0);
+            assert_eq!(m.len(), 0);
+            assert_eq!(p.len(), 1);
+            assert_eq!(p.back(), Some(&1));
+            assert_eq!(p.front(), Some(&1));
+        }
+
+        // not singleton, forwards
+        {
+            let u = vec![1i,2,3,4,5];
+            let mut m = list_from(u.as_slice());
+            let mut n = m.split_off(2);
+            assert_eq!(m.len(), 2);
+            assert_eq!(n.len(), 3);
+            for elt in range(1i, 3) {
+                assert_eq!(m.pop_front(), Some(elt));
+            }
+            for elt in range(3i, 6) {
+                assert_eq!(n.pop_front(), Some(elt));
+            }
+        }
+        // not singleton, backwards
+        {
+            let u = vec![1i,2,3,4,5];
+            let mut m = list_from(u.as_slice());
+            let mut n = m.split_off(4);
+            assert_eq!(m.len(), 4);
+            assert_eq!(n.len(), 1);
+            for elt in range(1i, 5) {
+                assert_eq!(m.pop_front(), Some(elt));
+            }
+            for elt in range(5i, 6) {
+                assert_eq!(n.pop_front(), Some(elt));
+            }
+        }
+
+    }
+
     #[test]
     fn test_iterator() {
         let m = generate_test();
@@ -1065,41 +1220,6 @@ mod tests {
         assert_eq!(i, v.len());
     }
 
-    #[allow(deprecated)]
-    #[test]
-    fn test_append() {
-        {
-            let mut m = DList::new();
-            let mut n = DList::new();
-            n.push_back(2i);
-            m.append(n);
-            assert_eq!(m.len(), 1);
-            assert_eq!(m.pop_back(), Some(2));
-            check_links(&m);
-        }
-        {
-            let mut m = DList::new();
-            let n = DList::new();
-            m.push_back(2i);
-            m.append(n);
-            assert_eq!(m.len(), 1);
-            assert_eq!(m.pop_back(), Some(2));
-            check_links(&m);
-        }
-
-        let v = vec![1i,2,3,4,5];
-        let u = vec![9i,8,1,2,3,4,5];
-        let mut m = list_from(v.as_slice());
-        m.append(list_from(u.as_slice()));
-        check_links(&m);
-        let mut sum = v;
-        sum.push_all(u.as_slice());
-        assert_eq!(sum.len(), m.len());
-        for elt in sum.into_iter() {
-            assert_eq!(m.pop_front(), Some(elt))
-        }
-    }
-
     #[bench]
     fn bench_collect_into(b: &mut test::Bencher) {
         let v = &[0i; 64];

branches/try/src/librustc/middle/infer/mod.rs

@@ -613,6 +613,39 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         self.commit_unconditionally(move || self.try(move |_| f()))
     }
 
+    /// Execute `f` and commit only the region bindings if successful.
+    /// The function f must be very careful not to leak any non-region
+    /// variables that get created.
+    pub fn commit_regions_if_ok<T, E, F>(&self, f: F) -> Result<T, E> where
+        F: FnOnce() -> Result<T, E>
+    {
+        debug!("commit_regions_if_ok()");
+        let CombinedSnapshot { type_snapshot,
+                               int_snapshot,
+                               float_snapshot,
+                               region_vars_snapshot } = self.start_snapshot();
+
+        let r = self.try(move |_| f());
+
+        // Roll back any non-region bindings - they should be resolved
+        // inside `f`, with, e.g. `resolve_type_vars_if_possible`.
+        self.type_variables
+            .borrow_mut()
+            .rollback_to(type_snapshot);
+        self.int_unification_table
+            .borrow_mut()
+            .rollback_to(int_snapshot);
+        self.float_unification_table
+            .borrow_mut()
+            .rollback_to(float_snapshot);
+
+        // Commit region vars that may escape through resolved types.
+        self.region_vars
+            .commit(region_vars_snapshot);
+
+        r
+    }
+
     /// Execute `f`, unroll bindings on panic
     pub fn try<T, E, F>(&self, f: F) -> Result<T, E> where
         F: FnOnce(&CombinedSnapshot) -> Result<T, E>

branches/try/src/librustc_back/target/apple_ios_base.rs

@@ -14,6 +14,7 @@ use target::TargetOptions;
 use self::Arch::*;
 
 #[allow(non_camel_case_types)]
+#[derive(Copy)]
 pub enum Arch {
     Armv7,
     Armv7s,
@@ -70,8 +71,16 @@ fn pre_link_args(arch: Arch) -> Vec<String> {
          "-Wl,-syslibroot".to_string(), get_sdk_root(sdk_name)]
 }
 
+fn target_cpu(arch: Arch) -> String {
+    match arch {
+        X86_64 => "x86-64",
+        _ => "generic",
+    }.to_string()
+}
+
 pub fn opts(arch: Arch) -> TargetOptions {
     TargetOptions {
+        cpu: target_cpu(arch),
         dynamic_linking: false,
         executables: true,
         // Although there is an experimental implementation of LLVM which

branches/try/src/librustc_back/target/x86_64_apple_darwin.rs

@@ -12,6 +12,7 @@ use target::Target;
 
 pub fn target() -> Target {
     let mut base = super::apple_base::opts();
+    base.cpu = "x86-64".to_string();
     base.eliminate_frame_pointer = false;
     base.pre_link_args.push("-m64".to_string());
 

branches/try/src/librustc_back/target/x86_64_pc_windows_gnu.rs

@@ -12,6 +12,7 @@ use target::Target;
 
 pub fn target() -> Target {
     let mut base = super::windows_base::opts();
+    base.cpu = "x86-64".to_string();
     // On Win64 unwinding is handled by the OS, so we can link libgcc statically.
     base.pre_link_args.push("-static-libgcc".to_string());
     base.pre_link_args.push("-m64".to_string());

branches/try/src/librustc_back/target/x86_64_unknown_dragonfly.rs

@@ -12,6 +12,7 @@ use target::Target;
 
 pub fn target() -> Target {
     let mut base = super::dragonfly_base::opts();
+    base.cpu = "x86-64".to_string();
     base.pre_link_args.push("-m64".to_string());
 
     Target {