---

yaml
---
r: 212944
b: refs/heads/master
c: 85be7c5
h: refs/heads/master
v: v3

Author: srwalter

[refs]

@@ -1,5 +1,5 @@
 ---
-refs/heads/master: 37cc79f81c62cbdf609e2760215725ecf76323c7
+refs/heads/master: 85be7c5f75522265aceb1b186d4f6aaa4014904c
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: ba0e1cd8147d452c356aacb29fb87568ca26f111
 refs/heads/try: 1864973ae17213c5a58c4dd3f9af6d1b6c7d2e05

trunk/src/doc/reference.md

@@ -638,7 +638,7 @@ apply to the crate as a whole.
 ```
 
 A crate that contains a `main` function can be compiled to an executable. If a
-`main` function is present, its return type must be [`unit`](#tuple-types)
+`main` function is present, its return type must be [`unit`](#primitive-types)
 and it must take no arguments.
 
 # Items and attributes
@@ -928,20 +928,21 @@ A _generic function_ allows one or more _parameterized types_ to appear in its
 signature. Each type parameter must be explicitly declared, in an
 angle-bracket-enclosed, comma-separated list following the function name.
 
-```rust,ignore
-// foo is generic over A and B
-
-fn foo<A, B>(x: A, y: B) {
+```{.ignore}
+fn iter<T, F>(seq: &[T], f: F) where T: Copy, F: Fn(T) {
+    for elt in seq { f(*elt); }
+}
+fn map<T, U, F>(seq: &[T], f: F) -> Vec<U> where T: Copy, U: Copy, F: Fn(T) -> U {
+    let mut acc = vec![];
+    for elt in seq { acc.push(f(*elt)); }
+    acc
+}
 ```
 
 Inside the function signature and body, the name of the type parameter can be
 used as a type name. [Trait](#traits) bounds can be specified for type parameters
 to allow methods with that trait to be called on values of that type. This is
-specified using the `where` syntax:
-
-```rust,ignore
-fn foo<T>(x: T) where T: Debug {
-```
+specified using the `where` syntax, as in the above example.
 
 When a generic function is referenced, its type is instantiated based on the
 context of the reference. For example, calling the `iter` function defined
@@ -2873,7 +2874,7 @@ The `+`, `-`, `*`, `/`, `%`, `&`, `|`, `^`, `<<`, and `>>` operators may be
 composed with the `=` operator. The expression `lval OP= val` is equivalent to
 `lval = lval OP val`. For example, `x = x + 1` may be written as `x += 1`.
 
-Any such expression always has the [`unit`](#tuple-types) type.
+Any such expression always has the [`unit`](#primitive-types) type.
 
 #### Operator precedence
 
@@ -3315,9 +3316,6 @@ assert!(b != "world");
 assert!(p.0 == 10);
 ```
 
-For historical reasons and convenience, the tuple type with no elements (`()`)
-is often called ‘unit’ or ‘the unit type’.
-
 ### Array, and Slice types
 
 Rust has two different types for a list of items:

trunk/src/doc/trpl/closures.md

@@ -120,7 +120,7 @@ let y = &mut num;
 ```
 
 If your closure requires it, however, Rust will take ownership and move
-the environment instead. This doesn’t work:
+the environment instead:
 
 ```rust,ignore
 let nums = vec![1, 2, 3];
@@ -130,7 +130,7 @@ let takes_nums = || nums;
 println!("{:?}", nums);
 ```
 
-We get this error:
+This gives us:
 
 ```text
 note: `nums` moved into closure environment here because it has type

trunk/src/doc/trpl/rust-inside-other-languages.md

@@ -66,14 +66,10 @@ threads = []
     5_000_000.times do
       count += 1
     end
-
-    count
   end
 end
 
-threads.each do |t|
-  puts "Thread finished with count=#{t.value}"
-end
+threads.each { |t| t.join }
 puts "done!"
 ```
 
@@ -107,26 +103,50 @@ use std::thread;
 fn process() {
     let handles: Vec<_> = (0..10).map(|_| {
         thread::spawn(|| {
-            let mut x = 0;
+            let mut _x = 0;
             for _ in (0..5_000_000) {
-                x += 1
+                _x += 1
             }
-	    x
         })
     }).collect();
 
     for h in handles {
-        println!("Thread finished with count={}",
-	    h.join().map_err(|_| "Could not join a thread!").unwrap());
+        h.join().ok().expect("Could not join a thread!");
     }
-    println!("done!");
 }
 ```
 
 Some of this should look familiar from previous examples. We spin up ten
 threads, collecting them into a `handles` vector. Inside of each thread, we
-loop five million times, and add one to `x` each time. Finally, we join on
-each thread.
+loop five million times, and add one to `_x` each time. Why the underscore?
+Well, if we remove it and compile:
+
+```bash
+$ cargo build
+   Compiling embed v0.1.0 (file:///home/steve/src/embed)
+src/lib.rs:3:1: 16:2 warning: function is never used: `process`, #[warn(dead_code)] on by default
+src/lib.rs:3 fn process() {
+src/lib.rs:4     let handles: Vec<_> = (0..10).map(|_| {
+src/lib.rs:5         thread::spawn(|| {
+src/lib.rs:6             let mut x = 0;
+src/lib.rs:7             for _ in (0..5_000_000) {
+src/lib.rs:8                 x += 1
+             ...
+src/lib.rs:6:17: 6:22 warning: variable `x` is assigned to, but never used, #[warn(unused_variables)] on by default
+src/lib.rs:6             let mut x = 0;
+                             ^~~~~
+```
+
+That first warning is because we are building a library. If we had a test
+for this function, the warning would go away. But for now, it’s never
+called.
+
+The second is related to `x` versus `_x`. Because we never actually _do_
+anything with `x`, we get a warning about it. In our case, that’s perfectly
+okay, as we’re just trying to waste CPU cycles. Prefixing `x` with the
+underscore removes the warning.
+
+Finally, we join on each thread.
 
 Right now, however, this is a Rust library, and it doesn’t expose anything
 that’s callable from C. If we tried to hook this up to another language right

trunk/src/doc/trpl/trait-objects.md

@@ -300,3 +300,7 @@ let y = TraitObject {
 // y.method();
 (y.vtable.method)(y.data);
 ```
+
+If `b` or `y` were owning trait objects (`Box<Foo>`), there would be a
+`(b.vtable.destructor)(b.data)` (respectively `y`) call when they went out of
+scope.

trunk/src/doc/trpl/traits.md

@@ -332,7 +332,7 @@ fn normal<T: ConvertTo<i64>>(x: &T) -> i64 {
 fn inverse<T>() -> T
         // this is using ConvertTo as if it were "ConvertFrom<i32>"
         where i32: ConvertTo<T> {
-    42.convert()
+    1i32.convert()
 }
 ```
 

trunk/src/libcollections/vec.rs

@@ -1469,26 +1469,42 @@ impl<T> ops::DerefMut for Vec<T> {
 impl<T> FromIterator<T> for Vec<T> {
     #[inline]
     fn from_iter<I: IntoIterator<Item=T>>(iterable: I) -> Vec<T> {
-        // Unroll the first iteration, as the vector is going to be
-        // expanded on this iteration in every case when the iterable is not
-        // empty, but the loop in extend_desugared() is not going to see the
-        // vector being full in the few subsequent loop iterations.
-        // So we get better branch prediction and the possibility to
-        // construct the vector with initial estimated capacity.
         let mut iterator = iterable.into_iter();
-        let mut vector = match iterator.next() {
-            None => return Vec::new(),
-            Some(element) => {
-                let (lower, _) = iterator.size_hint();
-                let mut vector = Vec::with_capacity(1 + lower);
-                unsafe {
-                    ptr::write(vector.get_unchecked_mut(0), element);
-                    vector.set_len(1);
-                }
-                vector
+        let (lower, _) = iterator.size_hint();
+        let mut vector = Vec::with_capacity(lower);
+
+        // This function should be the moral equivalent of:
+        //
+        //      for item in iterator {
+        //          vector.push(item);
+        //      }
+        //
+        // This equivalent crucially runs the iterator precisely once. Below we
+        // actually in theory run the iterator twice (one without bounds checks
+        // and one with). To achieve the "moral equivalent", we use the `if`
+        // statement below to break out early.
+        //
+        // If the first loop has terminated, then we have one of two conditions.
+        //
+        // 1. The underlying iterator returned `None`. In this case we are
+        //    guaranteed that less than `vector.capacity()` elements have been
+        //    returned, so we break out early.
+        // 2. The underlying iterator yielded `vector.capacity()` elements and
+        //    has not yielded `None` yet. In this case we run the iterator to
+        //    its end below.
+        for element in iterator.by_ref().take(vector.capacity()) {
+            let len = vector.len();
+            unsafe {
+                ptr::write(vector.get_unchecked_mut(len), element);
+                vector.set_len(len + 1);
+            }
+        }
+
+        if vector.len() == vector.capacity() {
+            for element in iterator {
+                vector.push(element);
             }
-        };
-        vector.extend_desugared(iterator);
+        }
         vector
     }
 }
@@ -1553,27 +1569,11 @@ impl<'a, T> IntoIterator for &'a mut Vec<T> {
 impl<T> Extend<T> for Vec<T> {
     #[inline]
     fn extend<I: IntoIterator<Item=T>>(&mut self, iterable: I) {
-        self.extend_desugared(iterable.into_iter())
-    }
-}
-
-impl<T> Vec<T> {
-    fn extend_desugared<I: Iterator<Item=T>>(&mut self, mut iterator: I) {
-        // This function should be the moral equivalent of:
-        //
-        //      for item in iterator {
-        //          self.push(item);
-        //      }
-        while let Some(element) = iterator.next() {
-            let len = self.len();
-            if len == self.capacity() {
-                let (lower, _) = iterator.size_hint();
-                self.reserve(lower + 1);
-            }
-            unsafe {
-                ptr::write(self.get_unchecked_mut(len), element);
-                self.set_len(len + 1);
-            }
+        let iterator = iterable.into_iter();
+        let (lower, _) = iterator.size_hint();
+        self.reserve(lower);
+        for element in iterator {
+            self.push(element)
         }
     }
 }

trunk/src/libcore/char.rs

@@ -74,8 +74,17 @@ pub const MAX: char = '\u{10ffff}';
 /// ```
 /// use std::char;
 ///
-/// assert_eq!(char::from_u32(0x2764), Some('❤'));
-/// assert_eq!(char::from_u32(0x110000), None); // invalid character
+/// let c = char::from_u32(10084); // produces `Some(❤)`
+/// assert_eq!(c, Some('❤'));
+/// ```
+///
+/// An invalid character:
+///
+/// ```
+/// use std::char;
+///
+/// let none = char::from_u32(1114112);
+/// assert_eq!(none, None);
 /// ```
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]

trunk/src/libcore/str/mod.rs

@@ -638,10 +638,10 @@ impl<'a, P: Pattern<'a>> SplitInternal<'a, P> {
 
 generate_pattern_iterators! {
     forward:
-        #[doc="Created with the method `.split()`."]
+        /// Created with the method `.split()`.
         struct Split;
     reverse:
-        #[doc="Created with the method `.rsplit()`."]
+        /// Created with the method `.rsplit()`.
         struct RSplit;
     stability:
         #[stable(feature = "rust1", since = "1.0.0")]
@@ -652,10 +652,10 @@ generate_pattern_iterators! {
 
 generate_pattern_iterators! {
     forward:
-        #[doc="Created with the method `.split_terminator()`."]
+        /// Created with the method `.split_terminator()`.
         struct SplitTerminator;
     reverse:
-        #[doc="Created with the method `.rsplit_terminator()`."]
+        /// Created with the method `.rsplit_terminator()`.
         struct RSplitTerminator;
     stability:
         #[stable(feature = "rust1", since = "1.0.0")]
@@ -698,10 +698,10 @@ impl<'a, P: Pattern<'a>> SplitNInternal<'a, P> {
 
 generate_pattern_iterators! {
     forward:
-        #[doc="Created with the method `.splitn()`."]
+        /// Created with the method `.splitn()`.
         struct SplitN;
     reverse:
-        #[doc="Created with the method `.rsplitn()`."]
+        /// Created with the method `.rsplitn()`.
         struct RSplitN;
     stability:
         #[stable(feature = "rust1", since = "1.0.0")]
@@ -732,10 +732,10 @@ impl<'a, P: Pattern<'a>> MatchIndicesInternal<'a, P> {
 
 generate_pattern_iterators! {
     forward:
-        #[doc="Created with the method `.match_indices()`."]
+        /// Created with the method `.match_indices()`.
         struct MatchIndices;
     reverse:
-        #[doc="Created with the method `.rmatch_indices()`."]
+        /// Created with the method `.rmatch_indices()`.
         struct RMatchIndices;
     stability:
         #[unstable(feature = "core",
@@ -773,10 +773,10 @@ impl<'a, P: Pattern<'a>> MatchesInternal<'a, P> {
 
 generate_pattern_iterators! {
     forward:
-        #[doc="Created with the method `.matches()`."]
+        /// Created with the method `.matches()`.
         struct Matches;
     reverse:
-        #[doc="Created with the method `.rmatches()`."]
+        /// Created with the method `.rmatches()`.
         struct RMatches;
     stability:
         #[unstable(feature = "core", reason = "type got recently added")]