extend the iterator tutorial + fix zero-size element vec iterators

doc/tutorial-container.md

@@ -205,3 +205,104 @@ println(fmt!("last: %?", it.next()));
 // the iterator is now fully consumed
 assert!(it.next().is_none());
 ~~~
+
+## Conversion
+
+Iterators offer generic conversion to containers with the `collect` adaptor:
+
+~~~
+let xs = [0, 1, 1, 2, 3, 5, 8];
+let ys = xs.rev_iter().skip(1).transform(|&x| x * 2).collect::<~[int]>();
+assert_eq!(ys, ~[10, 6, 4, 2, 2, 0]);
+~~~
+
+The method requires a type hint for the container type, if the surrounding code
+does not provide sufficient information.
+
+Containers can provide conversion from iterators through `collect` by
+implementing the `FromIterator` trait. For example, the implementation for
+vectors is as follows:
+
+~~~
+impl<A, T: Iterator<A>> FromIterator<A, T> for ~[A] {
+    pub fn from_iterator(iterator: &mut T) -> ~[A] {
+        let (lower, _) = iterator.size_hint();
+        let mut xs = with_capacity(lower);
+        for iterator.advance |x| {
+            xs.push(x);
+        }
+        xs
+    }
+}
+~~~
+
+### Size hints
+
+The `Iterator` trait provides a `size_hint` default method, returning a lower
+bound and optionally on upper bound on the length of the iterator:
+
+~~~
+fn size_hint(&self) -> (uint, Option<uint>) { (0, None) }
+~~~
+
+The vector implementation of `FromIterator` from above uses the lower bound
+to pre-allocate enough space to hold the minimum number of elements the
+iterator will yield.
+
+The default implementation is always correct, but it should be overridden if
+the iterator can provide better information.
+
+The `ZeroStream` from earlier can provide an exact lower and upper bound:
+
+~~~
+/// A stream of N zeroes
+struct ZeroStream {
+    priv remaining: uint
+}
+
+impl ZeroStream {
+    fn new(n: uint) -> ZeroStream {
+        ZeroStream { remaining: n }
+    }
+
+    fn size_hint(&self) -> (uint, Option<uint>) {
+        (self.remaining, Some(self.remaining))
+    }
+}
+
+impl Iterator<int> for ZeroStream {
+    fn next(&mut self) -> Option<int> {
+        if self.remaining == 0 {
+            None
+        } else {
+            self.remaining -= 1;
+            Some(0)
+        }
+    }
+}
+~~~
+
+## Double-ended iterators
+
+The `DoubleEndedIterator` trait represents an iterator able to yield elements
+from either end of a range. It inherits from the `Iterator` trait and extends
+it with the `next_back` function.
+
+A `DoubleEndedIterator` can be flipped with the `invert` adaptor, returning
+another `DoubleEndedIterator` with `next` and `next_back` exchanged.
+
+~~~
+let xs = [1, 2, 3, 4, 5, 6];
+let mut it = xs.iter();
+println(fmt!("%?", it.next())); // prints `Some(&1)`
+println(fmt!("%?", it.next())); // prints `Some(&2)`
+println(fmt!("%?", it.next_back())); // prints `Some(&6)`
+
+// prints `5`, `4` and `3`
+for it.invert().advance |&x| {
+    println(fmt!("%?", x))
+}
+~~~
+
+The `rev_iter` and `mut_rev_iter` methods on vectors just return an inverted
+version of the standard immutable and mutable vector iterators.

src/libextra/bitv.rs

@@ -104,7 +104,7 @@ impl SmallBitv {
     }
 
     #[inline]
-    pub fn invert(&mut self) { self.bits = !self.bits; }
+    pub fn negate(&mut self) { self.bits = !self.bits; }
 }
 
 struct BigBitv {
@@ -160,7 +160,7 @@ impl BigBitv {
     }
 
     #[inline]
-    pub fn invert(&mut self) { for self.each_storage |w| { *w = !*w } }
+    pub fn negate(&mut self) { for self.each_storage |w| { *w = !*w } }
 
     #[inline]
     pub fn union(&mut self, b: &BigBitv, nbits: uint) -> bool {
@@ -366,9 +366,9 @@ impl Bitv {
 
     /// Invert all bits
     #[inline]
-    pub fn invert(&mut self) {
+    pub fn negate(&mut self) {
       match self.rep {
-        Small(ref mut b) => b.invert(),
+        Small(ref mut b) => b.negate(),
         Big(ref mut s) => for s.each_storage() |w| { *w = !*w } }
     }
 

src/libextra/flatpipes.rs

@@ -446,7 +446,7 @@ pub mod flatteners {
                               T: Decodable<D>>(
                               buf: &[u8])
                               -> T {
-        let buf = vec::to_owned(buf);
+        let buf = buf.to_owned();
         let buf_reader = @BufReader::new(buf);
         let reader = buf_reader as @Reader;
         let mut deser: D = FromReader::from_reader(reader);

src/libextra/getopts.rs

@@ -343,7 +343,7 @@ pub fn getopts(args: &[~str], opts: &[Opt]) -> Result {
         }
         i += 1;
     }
-    return Ok(Matches {opts: vec::to_owned(opts),
+    return Ok(Matches {opts: opts.to_owned(),
                vals: vals,
                free: free});
 }

src/libextra/md4.rs

@@ -28,7 +28,7 @@ pub fn md4(msg: &[u8]) -> Quad {
     let orig_len: u64 = (msg.len() * 8u) as u64;
 
     // pad message
-    let mut msg = vec::append(vec::to_owned(msg), [0x80u8]);
+    let mut msg = vec::append(msg.to_owned(), [0x80u8]);
     let mut bitlen = orig_len + 8u64;
     while (bitlen + 64u64) % 512u64 > 0u64 {
         msg.push(0u8);

src/libextra/num/bigint.rs

@@ -567,7 +567,7 @@ impl BigUint {
     /// Creates and initializes an BigUint.
 
     pub fn from_slice(slice: &[BigDigit]) -> BigUint {
-        return BigUint::new(vec::to_owned(slice));
+        return BigUint::new(slice.to_owned());
     }
 
     /// Creates and initializes an BigUint.

src/libextra/stats.rs

@@ -12,7 +12,6 @@ use sort;
 use std::cmp;
 use std::io;
 use std::num;
-use std::vec;
 
 // NB: this can probably be rewritten in terms of num::Num
 // to be less f64-specific.
@@ -200,13 +199,13 @@ impl<'self> Stats for &'self [f64] {
     }
 
     fn percentile(self, pct: f64) -> f64 {
-        let mut tmp = vec::to_owned(self);
+        let mut tmp = self.to_owned();
         sort::tim_sort(tmp);
         percentile_of_sorted(tmp, pct)
     }
 
     fn quartiles(self) -> (f64,f64,f64) {
-        let mut tmp = vec::to_owned(self);
+        let mut tmp = self.to_owned();
         sort::tim_sort(tmp);
         let a = percentile_of_sorted(tmp, 25.0);
         let b = percentile_of_sorted(tmp, 50.0);
@@ -251,7 +250,7 @@ priv fn percentile_of_sorted(sorted_samples: &[f64],
 ///
 /// See: http://en.wikipedia.org/wiki/Winsorising
 pub fn winsorize(samples: &mut [f64], pct: f64) {
-    let mut tmp = vec::to_owned(samples);
+    let mut tmp = samples.to_owned();
     sort::tim_sort(tmp);
     let lo = percentile_of_sorted(tmp, pct);
     let hi = percentile_of_sorted(tmp, 100.0-pct);

src/librustc/metadata/decoder.rs

@@ -714,7 +714,7 @@ pub fn maybe_get_item_ast(cdata: cmd, tcx: ty::ctxt,
     let item_doc = lookup_item(id, cdata.data);
     let path = {
         let item_path = item_path(item_doc);
-        vec::to_owned(item_path.init())
+        item_path.init().to_owned()
     };
     match decode_inlined_item(cdata, tcx, copy path, item_doc) {
       Some(ref ii) => csearch::found((/*bad*/copy *ii)),

src/librustc/metadata/encoder.rs

@@ -1659,7 +1659,7 @@ pub fn encode_metadata(parms: EncodeParams, crate: &crate) -> ~[u8] {
 
     let writer_bytes: &mut ~[u8] = wr.bytes;
 
-    vec::to_owned(metadata_encoding_version) +
+    metadata_encoding_version.to_owned() +
         flate::deflate_bytes(*writer_bytes)
 }
 

src/librustc/middle/check_match.rs

@@ -484,7 +484,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
                 match cx.tcx.def_map.find(&pat_id) {
                     Some(&def_variant(_, id)) => {
                         if variant(id) == *ctor_id {
-                            Some(vec::to_owned(r.tail()))
+                            Some(r.tail().to_owned())
                         } else {
                             None
                         }
@@ -522,7 +522,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
                             _ => fail!("type error")
                         };
                         if match_ {
-                            Some(vec::to_owned(r.tail()))
+                            Some(r.tail().to_owned())
                         } else {
                             None
                         }
@@ -569,7 +569,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
                             _ => fail!("type error")
                         };
                         if match_ {
-                            Some(vec::to_owned(r.tail()))
+                            Some(r.tail().to_owned())
                         } else {
                             None
                         }
@@ -579,7 +579,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
                             Some(args) => args,
                             None => vec::from_elem(arity, wild())
                         };
-                        Some(vec::append(args, vec::to_owned(r.tail())))
+                        Some(vec::append(args, r.tail()))
                     }
                     def_variant(_, _) => None,
 
@@ -591,7 +591,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
                             Some(args) => new_args = args,
                             None => new_args = vec::from_elem(arity, wild())
                         }
-                        Some(vec::append(new_args, vec::to_owned(r.tail())))
+                        Some(vec::append(new_args, r.tail()))
                     }
                     _ => None
                 }
@@ -609,7 +609,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
                                     _ => wild()
                                 }
                             });
-                            Some(vec::append(args, vec::to_owned(r.tail())))
+                            Some(vec::append(args, r.tail()))
                         } else {
                             None
                         }
@@ -640,7 +640,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
                                 _ => wild()
                             }
                         }).collect();
-                        Some(vec::append(args, vec::to_owned(r.tail())))
+                        Some(vec::append(args, r.tail()))
                     }
                 }
             }
@@ -676,14 +676,14 @@ pub fn specialize(cx: &MatchCheckCtxt,
                     single => true,
                     _ => fail!("type error")
                 };
-                if match_ { Some(vec::to_owned(r.tail())) } else { None }
+                if match_ { Some(r.tail().to_owned()) } else { None }
             }
             pat_range(lo, hi) => {
                 let (c_lo, c_hi) = match *ctor_id {
                     val(ref v) => ((/*bad*/copy *v), (/*bad*/copy *v)),
                     range(ref lo, ref hi) =>
                         ((/*bad*/copy *lo), (/*bad*/copy *hi)),
-                    single => return Some(vec::to_owned(r.tail())),
+                    single => return Some(r.tail().to_owned()),
                     _ => fail!("type error")
                 };
                 let v_lo = eval_const_expr(cx.tcx, lo);
@@ -693,7 +693,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
                 let m2 = compare_const_vals(&c_hi, &v_hi);
                 match (m1, m2) {
                     (Some(val1), Some(val2)) if val1 >= 0 && val2 <= 0 => {
-                        Some(vec::to_owned(r.tail()))
+                        Some(r.tail().to_owned())
                     },
                     (Some(_), Some(_)) => None,
                     _ => {
@@ -734,7 +734,7 @@ pub fn specialize(cx: &MatchCheckCtxt,
 }
 
 pub fn default(cx: &MatchCheckCtxt, r: &[@pat]) -> Option<~[@pat]> {
-    if is_wild(cx, r[0]) { Some(vec::to_owned(r.tail())) }
+    if is_wild(cx, r[0]) { Some(r.tail().to_owned()) }
     else { None }
 }
 

src/librustc/middle/trans/adt.rs

@@ -47,7 +47,6 @@
 use std::container::Map;
 use std::libc::c_ulonglong;
 use std::option::{Option, Some, None};
-use std::vec;
 
 use lib::llvm::{ValueRef, True, IntEQ, IntNE};
 use middle::trans::_match;
@@ -219,7 +218,7 @@ fn mk_struct(cx: &mut CrateContext, tys: &[ty::t], packed: bool) -> Struct {
         size: machine::llsize_of_alloc(cx, llty_rec) /*bad*/as u64,
         align: machine::llalign_of_min(cx, llty_rec) /*bad*/as u64,
         packed: packed,
-        fields: vec::to_owned(tys)
+        fields: tys.to_owned(),
     }
 }
 

src/librustc/middle/ty.rs

@@ -3782,7 +3782,7 @@ pub fn item_path(cx: ctxt, id: ast::def_id) -> ast_map::path {
           }
 
           ast_map::node_variant(ref variant, _, path) => {
-            vec::append_one(vec::to_owned(path.init()),
+            vec::append_one(path.init().to_owned(),
                             ast_map::path_name((*variant).node.name))
           }
 

src/libstd/prelude.rs

@@ -47,8 +47,9 @@ pub use cmp::{Eq, ApproxEq, Ord, TotalEq, TotalOrd, Ordering, Less, Equal, Great
 pub use char::Char;
 pub use container::{Container, Mutable, Map, Set};
 pub use hash::Hash;
-pub use iter::{Times};
-pub use iterator::{Iterator, IteratorUtil, OrdIterator};
+pub use iter::Times;
+pub use iterator::{Iterator, IteratorUtil, DoubleEndedIterator, DoubleEndedIteratorUtil};
+pub use iterator::OrdIterator;
 pub use num::{Num, NumCast};
 pub use num::{Orderable, Signed, Unsigned, Round};
 pub use num::{Algebraic, Trigonometric, Exponential, Hyperbolic};

src/libstd/rand.rs

@@ -591,7 +591,7 @@ impl<R: Rng> RngUtil for R {
 
     /// Shuffle a vec
     fn shuffle<T:Copy>(&mut self, values: &[T]) -> ~[T] {
-        let mut m = vec::to_owned(values);
+        let mut m = values.to_owned();
         self.shuffle_mut(m);
         m
     }

src/libstd/vec.rs

@@ -30,7 +30,6 @@ use ptr::RawPtr;
 use rt::global_heap::malloc_raw;
 use rt::global_heap::realloc_raw;
 use sys;
-use sys::size_of;
 use uint;
 use unstable::intrinsics;
 #[cfg(stage0)]
@@ -91,11 +90,6 @@ pub fn from_elem<T:Copy>(n_elts: uint, t: T) -> ~[T] {
     }
 }
 
-/// Creates a new unique vector with the same contents as the slice
-pub fn to_owned<T:Copy>(t: &[T]) -> ~[T] {
-    from_fn(t.len(), |i| copy t[i])
-}
-
 /// Creates a new vector with a capacity of `capacity`
 #[cfg(stage0)]
 pub fn with_capacity<T>(capacity: uint) -> ~[T] {
@@ -114,7 +108,7 @@ pub fn with_capacity<T>(capacity: uint) -> ~[T] {
             vec
         } else {
             let alloc = capacity * sys::nonzero_size_of::<T>();
-            let ptr = malloc_raw(alloc + size_of::<raw::VecRepr>()) as *mut raw::VecRepr;
+            let ptr = malloc_raw(alloc + sys::size_of::<raw::VecRepr>()) as *mut raw::VecRepr;
             (*ptr).unboxed.alloc = alloc;
             (*ptr).unboxed.fill = 0;
             cast::transmute(ptr)
@@ -756,10 +750,13 @@ impl<'self,T> ImmutableVector<'self, T> for &'self [T] {
     fn iter(self) -> VecIterator<'self, T> {
         unsafe {
             let p = vec::raw::to_ptr(self);
-            VecIterator{ptr: p, end: p.offset(self.len()),
+            VecIterator{ptr: p,
+                        end: cast::transmute(p as uint + self.len() *
+                                             sys::nonzero_size_of::<T>()),
                         lifetime: cast::transmute(p)}
         }
     }
+
     #[inline]
     fn rev_iter(self) -> VecRevIterator<'self, T> {
         self.iter().invert()
@@ -1153,7 +1150,7 @@ impl<T> OwnedVector<T> for ~[T] {
                     ::at_vec::raw::reserve_raw(td, ptr, n);
                 } else {
                     let alloc = n * sys::nonzero_size_of::<T>();
-                    *ptr = realloc_raw(*ptr as *mut c_void, alloc + size_of::<raw::VecRepr>())
+                    *ptr = realloc_raw(*ptr as *mut c_void, alloc + sys::size_of::<raw::VecRepr>())
                            as *mut raw::VecRepr;
                     (**ptr).unboxed.alloc = alloc;
                 }
@@ -1182,7 +1179,7 @@ impl<T> OwnedVector<T> for ~[T] {
                     ::at_vec::raw::reserve_raw(td, ptr, n);
                 } else {
                     let alloc = n * sys::nonzero_size_of::<T>();
-                    let size = alloc + size_of::<raw::VecRepr>();
+                    let size = alloc + sys::size_of::<raw::VecRepr>();
                     if alloc / sys::nonzero_size_of::<T>() != n || size < alloc {
                         fail!("vector size is too large: %u", n);
                     }
@@ -1716,7 +1713,9 @@ impl<'self,T> MutableVector<'self, T> for &'self mut [T] {
     fn mut_iter(self) -> VecMutIterator<'self, T> {
         unsafe {
             let p = vec::raw::to_mut_ptr(self);
-            VecMutIterator{ptr: p, end: p.offset(self.len()),
+            VecMutIterator{ptr: p,
+                           end: cast::transmute(p as uint + self.len() *
+                                                sys::nonzero_size_of::<T>()),
                            lifetime: cast::transmute(p)}
         }
     }
@@ -2093,7 +2092,11 @@ macro_rules! iterator {
                         None
                     } else {
                         let old = self.ptr;
-                        self.ptr = self.ptr.offset(1);
+                        // purposefully don't use 'ptr.offset' because for
+                        // vectors with 0-size elements this would return the
+                        // same pointer.
+                        self.ptr = cast::transmute(self.ptr as uint +
+                                                   sys::nonzero_size_of::<T>());
                         Some(cast::transmute(old))
                     }
                 }
@@ -2102,7 +2105,7 @@ macro_rules! iterator {
             #[inline]
             fn size_hint(&self) -> (uint, Option<uint>) {
                 let diff = (self.end as uint) - (self.ptr as uint);
-                let exact = diff / size_of::<$elem>();
+                let exact = diff / sys::nonzero_size_of::<$elem>();
                 (exact, Some(exact))
             }
         }
@@ -2119,7 +2122,9 @@ macro_rules! double_ended_iterator {
                     if self.end == self.ptr {
                         None
                     } else {
-                        self.end = self.end.offset(-1);
+                        // See above for why 'ptr.offset' isn't used
+                        self.end = cast::transmute(self.end as uint -
+                                                   sys::nonzero_size_of::<T>());
                         Some(cast::transmute(self.end))
                     }
                 }
@@ -2211,7 +2216,6 @@ impl<A, T: Iterator<A>> FromIterator<A, T> for ~[A] {
     }
 }
 
-
 #[cfg(test)]
 mod tests {
     use option::{None, Option, Some};
@@ -2676,19 +2680,19 @@ mod tests {
         let mut results: ~[~[int]];
 
         results = ~[];
-        for each_permutation([]) |v| { results.push(to_owned(v)); }
+        for each_permutation([]) |v| { results.push(v.to_owned()); }
         assert_eq!(results, ~[~[]]);
 
         results = ~[];
-        for each_permutation([7]) |v| { results.push(to_owned(v)); }
+        for each_permutation([7]) |v| { results.push(v.to_owned()); }
         assert_eq!(results, ~[~[7]]);
 
         results = ~[];
-        for each_permutation([1,1]) |v| { results.push(to_owned(v)); }
+        for each_permutation([1,1]) |v| { results.push(v.to_owned()); }
         assert_eq!(results, ~[~[1,1],~[1,1]]);
 
         results = ~[];
-        for each_permutation([5,2,0]) |v| { results.push(to_owned(v)); }
+        for each_permutation([5,2,0]) |v| { results.push(v.to_owned()); }
         assert!(results ==
             ~[~[5,2,0],~[5,0,2],~[2,5,0],~[2,0,5],~[0,5,2],~[0,2,5]]);
     }
@@ -3375,4 +3379,50 @@ mod tests {
 
         assert_eq!(values, [2, 3, 5, 6, 7]);
     }
+
+    #[deriving(Eq)]
+    struct Foo;
+
+    #[test]
+    fn test_iter_zero_sized() {
+        let mut v = ~[Foo, Foo, Foo];
+        assert_eq!(v.len(), 3);
+        let mut cnt = 0;
+
+        for v.iter().advance |f| {
+            assert!(*f == Foo);
+            cnt += 1;
+        }
+        assert_eq!(cnt, 3);
+
+        for v.slice(1, 3).iter().advance |f| {
+            assert!(*f == Foo);
+            cnt += 1;
+        }
+        assert_eq!(cnt, 5);
+
+        for v.mut_iter().advance |f| {
+            assert!(*f == Foo);
+            cnt += 1;
+        }
+        assert_eq!(cnt, 8);
+
+        for v.consume_iter().advance |f| {
+            assert!(f == Foo);
+            cnt += 1;
+        }
+        assert_eq!(cnt, 11);
+
+        let xs = ~[Foo, Foo, Foo];
+        assert_eq!(fmt!("%?", xs.slice(0, 2).to_owned()), ~"~[{}, {}]");
+
+        let xs: [Foo, ..3] = [Foo, Foo, Foo];
+        assert_eq!(fmt!("%?", xs.slice(0, 2).to_owned()), ~"~[{}, {}]");
+        cnt = 0;
+        for xs.iter().advance |f| {
+            assert!(*f == Foo);
+            cnt += 1;
+        }
+        assert!(cnt == 3);
+    }
 }

src/libsyntax/attr.rs

@@ -20,7 +20,6 @@ use diagnostic::span_handler;
 use parse::comments::{doc_comment_style, strip_doc_comment_decoration};
 
 use std::hashmap::HashSet;
-use std::vec;
 /* Constructors */
 
 pub fn mk_name_value_item_str(name: @str, value: @str)
@@ -256,7 +255,7 @@ pub fn last_meta_item_list_by_name(items: ~[@ast::meta_item], name: &str)
 
 pub fn sort_meta_items(items: &[@ast::meta_item]) -> ~[@ast::meta_item] {
     // This is sort of stupid here, converting to a vec of mutables and back
-    let mut v = vec::to_owned(items);
+    let mut v = items.to_owned();
     do extra::sort::quick_sort(v) |ma, mb| {
         get_meta_item_name(*ma) <= get_meta_item_name(*mb)
     }

src/libsyntax/ext/asm.rs

@@ -19,8 +19,6 @@ use ext::base::*;
 use parse;
 use parse::token;
 
-use std::vec;
-
 enum State {
     Asm,
     Outputs,
@@ -43,7 +41,7 @@ pub fn expand_asm(cx: @ExtCtxt, sp: span, tts: &[ast::token_tree])
                -> base::MacResult {
     let p = parse::new_parser_from_tts(cx.parse_sess(),
                                        cx.cfg(),
-                                       vec::to_owned(tts));
+                                       tts.to_owned());
 
     let mut asm = @"";
     let mut outputs = ~[];

src/libsyntax/ext/base.rs

@@ -18,7 +18,6 @@ use parse;
 use parse::token;
 use parse::token::{ident_to_str, intern, str_to_ident};
 
-use std::vec;
 use std::hashmap::HashMap;
 
 // new-style macro! tt code:
@@ -362,7 +361,7 @@ pub fn get_exprs_from_tts(cx: @ExtCtxt, tts: &[ast::token_tree])
                        -> ~[@ast::expr] {
     let p = parse::new_parser_from_tts(cx.parse_sess(),
                                        cx.cfg(),
-                                       vec::to_owned(tts));
+                                       tts.to_owned());
     let mut es = ~[];
     while *p.token != token::EOF {
         if es.len() != 0 {

src/libsyntax/ext/log_syntax.rs

@@ -15,7 +15,6 @@ use ext::base;
 use print;
 use parse::token::{get_ident_interner};
 
-use std::vec;
 use std::io;
 
 pub fn expand_syntax_ext(cx: @ExtCtxt,
@@ -26,7 +25,7 @@ pub fn expand_syntax_ext(cx: @ExtCtxt,
     cx.print_backtrace();
     io::stdout().write_line(
         print::pprust::tt_to_str(
-            &ast::tt_delim(vec::to_owned(tt)),
+            &ast::tt_delim(tt.to_owned()),
             get_ident_interner()));
 
     //trivial expression

src/libsyntax/ext/quote.rs

@@ -17,8 +17,6 @@ use parse::token::*;
 use parse::token;
 use parse;
 
-use std::vec;
-
 /**
 *
 * Quasiquoting works via token trees.
@@ -653,7 +651,7 @@ fn expand_tts(cx: @ExtCtxt,
     let p = parse::new_parser_from_tts(
         cx.parse_sess(),
         cx.cfg(),
-        vec::to_owned(tts)
+        tts.to_owned()
     );
     *p.quote_depth += 1u;
     let tts = p.parse_all_token_trees();

src/libsyntax/ext/trace_macros.rs

@@ -16,8 +16,6 @@ use parse::lexer::{new_tt_reader, reader};
 use parse::parser::Parser;
 use parse::token::keywords;
 
-use std::vec;
-
 pub fn expand_trace_macros(cx: @ExtCtxt,
                            sp: span,
                            tt: &[ast::token_tree])
@@ -27,7 +25,7 @@ pub fn expand_trace_macros(cx: @ExtCtxt,
     let tt_rdr = new_tt_reader(
         copy cx.parse_sess().span_diagnostic,
         None,
-        vec::to_owned(tt)
+        tt.to_owned()
     );
     let rdr = tt_rdr as @reader;
     let rust_parser = Parser(

src/libsyntax/ext/tt/macro_rules.rs

@@ -23,7 +23,6 @@ use parse::token::{get_ident_interner, special_idents, gensym_ident, ident_to_st
 use parse::token::{FAT_ARROW, SEMI, nt_matchers, nt_tt};
 use print;
 
-use std::vec;
 use std::io;
 
 pub fn add_new_extension(cx: @ExtCtxt,
@@ -82,7 +81,7 @@ pub fn add_new_extension(cx: @ExtCtxt,
             io::println(fmt!("%s! { %s }",
                              cx.str_of(name),
                              print::pprust::tt_to_str(
-                                 &ast::tt_delim(vec::to_owned(arg)),
+                                 &ast::tt_delim(arg.to_owned()),
                                  get_ident_interner())));
         }
 
@@ -99,7 +98,7 @@ pub fn add_new_extension(cx: @ExtCtxt,
                 let arg_rdr = new_tt_reader(
                     s_d,
                     None,
-                    vec::to_owned(arg)
+                    arg.to_owned()
                 ) as @reader;
                 match parse(cx.parse_sess(), cx.cfg(), arg_rdr, *mtcs) {
                   success(named_matches) => {

src/test/run-pass/rcvr-borrowed-to-slice.rs

@@ -11,19 +11,17 @@
 use std::vec;
 
 trait sum {
-    fn sum(self) -> int;
+    fn sum_(self) -> int;
 }
 
 // Note: impl on a slice
 impl<'self> sum for &'self [int] {
-    fn sum(self) -> int {
-        let mut sum = 0;
-        for self.iter().advance |e| { sum += *e; }
-        return sum;
+    fn sum_(self) -> int {
+        self.iter().fold(0, |a, &b| a + b)
     }
 }
 
-fn call_sum(x: &[int]) -> int { x.sum() }
+fn call_sum(x: &[int]) -> int { x.sum_() }
 
 pub fn main() {
     let x = ~[1, 2, 3];
@@ -32,12 +30,12 @@ pub fn main() {
     assert_eq!(y, 6);
 
     let mut x = ~[1, 2, 3];
-    let y = x.sum();
+    let y = x.sum_();
     debug!("y==%d", y);
     assert_eq!(y, 6);
 
     let x = ~[1, 2, 3];
-    let y = x.sum();
+    let y = x.sum_();
     debug!("y==%d", y);
     assert_eq!(y, 6);
 }