libstd: Fix merge fallout.

22 files changed, 1042 insertions, 20 deletions

diff --git a/src/librustc/metadata/csearch.rs b/src/librustc/metadata/csearch.rs
index b35904dbdae..57d6c46d9f3 100644
--- a/src/librustc/metadata/csearch.rs
+++ b/src/librustc/metadata/csearch.rs
@@ -54,18 +54,6 @@ pub fn each_lang_item(cstore: @mut cstore::CStore,
 }
 
 /// Iterates over all the paths in the given crate.
-#[cfg(stage0)]
-pub fn each_path(cstore: @mut cstore::CStore,
-                 cnum: ast::crate_num,
-                 f: &fn(&str, decoder::def_like, ast::visibility) -> bool) {
-    let crate_data = cstore::get_crate_data(cstore, cnum);
-    let get_crate_data: decoder::GetCrateDataCb = |cnum| {
-        cstore::get_crate_data(cstore, cnum)
-    };
-    decoder::each_path(cstore.intr, crate_data, get_crate_data, f)
-}
-/// Iterates over all the paths in the given crate.
-#[cfg(not(stage0))]
 pub fn each_path(cstore: @mut cstore::CStore,
                  cnum: ast::crate_num,
                  f: &fn(&str, decoder::def_like, ast::visibility) -> bool)
diff --git a/src/librustc/metadata/decoder.rs b/src/librustc/metadata/decoder.rs
index de44b74528d..2cc0382269e 100644
--- a/src/librustc/metadata/decoder.rs
+++ b/src/librustc/metadata/decoder.rs
@@ -566,14 +566,6 @@ pub fn _each_path(intr: @ident_interner,
     return broken;
 }
 
-#[cfg(stage0)]
-pub fn each_path(intr: @ident_interner,
-                 cdata: cmd,
-                 get_crate_data: GetCrateDataCb,
-                 f: &fn(&str, def_like, ast::visibility) -> bool) {
-    _each_path(intr, cdata, get_crate_data, f);
-}
-#[cfg(not(stage0))]
 pub fn each_path(intr: @ident_interner,
                  cdata: cmd,
                  get_crate_data: GetCrateDataCb,
diff --git a/src/librustc/middle/borrowck/gather_loans/lifetime.rs b/src/librustc/middle/borrowck/gather_loans/lifetime.rs
index f91fdfe232c..f7b30e22f01 100644
--- a/src/librustc/middle/borrowck/gather_loans/lifetime.rs
+++ b/src/librustc/middle/borrowck/gather_loans/lifetime.rs
@@ -11,6 +11,8 @@
 //! This module implements the check that the lifetime of a borrow
 //! does not exceed the lifetime of the value being borrowed.
 
+use core::prelude::*;
+
 use middle::borrowck::*;
 use mc = middle::mem_categorization;
 use middle::ty;
diff --git a/src/librustc/middle/borrowck/gather_loans/mod.rs b/src/librustc/middle/borrowck/gather_loans/mod.rs
index 3d2c318a87e..a422d99b6f5 100644
--- a/src/librustc/middle/borrowck/gather_loans/mod.rs
+++ b/src/librustc/middle/borrowck/gather_loans/mod.rs
@@ -16,6 +16,8 @@
 // their associated scopes.  In phase two, checking loans, we will then make
 // sure that all of these loans are honored.
 
+use core::prelude::*;
+
 use middle::borrowck::*;
 use mc = middle::mem_categorization;
 use middle::pat_util;
diff --git a/src/librustc/middle/borrowck/gather_loans/restrictions.rs b/src/librustc/middle/borrowck/gather_loans/restrictions.rs
index ff6ad87846c..42b1c40a4b3 100644
--- a/src/librustc/middle/borrowck/gather_loans/restrictions.rs
+++ b/src/librustc/middle/borrowck/gather_loans/restrictions.rs
@@ -10,6 +10,8 @@
 
 //! Computes the restrictions that result from a borrow.
 
+use core::prelude::*;
+
 use middle::borrowck::*;
 use mc = middle::mem_categorization;
 use middle::ty;
diff --git a/src/librustc/middle/borrowck/mod.rs b/src/librustc/middle/borrowck/mod.rs
index bc3db4602b0..39479e726f8 100644
--- a/src/librustc/middle/borrowck/mod.rs
+++ b/src/librustc/middle/borrowck/mod.rs
@@ -10,6 +10,8 @@
 
 /*! See doc.rs for a thorough explanation of the borrow checker */
 
+use core::prelude::*;
+
 use mc = middle::mem_categorization;
 use middle::ty;
 use middle::typeck;
diff --git a/src/librustc/middle/resolve.rs b/src/librustc/middle/resolve.rs
index b2ef0c46afb..6a6746ab20b 100644
--- a/src/librustc/middle/resolve.rs
+++ b/src/librustc/middle/resolve.rs
@@ -22,6 +22,7 @@ use middle::lint::unused_imports;
 use middle::pat_util::pat_bindings;
 
 use syntax::ast::*;
+use syntax::ast;
 use syntax::ast_util::{def_id_of_def, local_def};
 use syntax::ast_util::{path_to_ident, walk_pat, trait_method_to_ty_method};
 use syntax::ast_util::{Privacy, Public, Private};
diff --git a/src/libcore/rt/comm.rs b/src/libstd/rt/comm.rs
index 576a402b709..576a402b709 100644
--- a/src/libcore/rt/comm.rs
+++ b/src/libstd/rt/comm.rs
diff --git a/src/libstd/rt/global_heap.rs b/src/libstd/rt/global_heap.rs
new file mode 100644
index 00000000000..ce7ff87b445
--- /dev/null
+++ b/src/libstd/rt/global_heap.rs
@@ -0,0 +1,87 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use sys::{TypeDesc, size_of};
+use libc::{c_void, size_t, uintptr_t};
+use c_malloc = libc::malloc;
+use c_free = libc::free;
+use managed::raw::{BoxHeaderRepr, BoxRepr};
+use cast::transmute;
+use unstable::intrinsics::{atomic_xadd,atomic_xsub};
+use ptr::null;
+use intrinsic::TyDesc;
+
+pub unsafe fn malloc(td: *TypeDesc, size: uint) -> *c_void {
+    assert!(td.is_not_null());
+
+    let total_size = get_box_size(size, (*td).align);
+    let p = c_malloc(total_size as size_t);
+    assert!(p.is_not_null());
+
+    // FIXME #3475: Converting between our two different tydesc types
+    let td: *TyDesc = transmute(td);
+
+    let box: &mut BoxRepr = transmute(p);
+    box.header.ref_count = -1; // Exchange values not ref counted
+    box.header.type_desc = td;
+    box.header.prev = null();
+    box.header.next = null();
+
+    let exchange_count = &mut *exchange_count_ptr();
+    atomic_xadd(exchange_count, 1);
+
+    return transmute(box);
+}
+/**
+Thin wrapper around libc::malloc, none of the box header
+stuff in exchange_alloc::malloc
+*/
+pub unsafe fn malloc_raw(size: uint) -> *c_void {
+    let p = c_malloc(size as size_t);
+    if p.is_null() {
+        fail!("Failure in malloc_raw: result ptr is null");
+    }
+    p
+}
+
+pub unsafe fn free(ptr: *c_void) {
+    let exchange_count = &mut *exchange_count_ptr();
+    atomic_xsub(exchange_count, 1);
+
+    assert!(ptr.is_not_null());
+    c_free(ptr);
+}
+///Thin wrapper around libc::free, as with exchange_alloc::malloc_raw
+pub unsafe fn free_raw(ptr: *c_void) {
+    c_free(ptr);
+}
+
+fn get_box_size(body_size: uint, body_align: uint) -> uint {
+    let header_size = size_of::<BoxHeaderRepr>();
+    // FIXME (#2699): This alignment calculation is suspicious. Is it right?
+    let total_size = align_to(header_size, body_align) + body_size;
+    return total_size;
+}
+
+// Rounds |size| to the nearest |alignment|. Invariant: |alignment| is a power
+// of two.
+fn align_to(size: uint, align: uint) -> uint {
+    assert!(align != 0);
+    (size + align - 1) & !(align - 1)
+}
+
+fn exchange_count_ptr() -> *mut int {
+    // XXX: Need mutable globals
+    unsafe { transmute(&rust_exchange_count) }
+}
+
+extern {
+    static rust_exchange_count: uintptr_t;
+}
diff --git a/src/libcore/rt/io/mock.rs b/src/libstd/rt/io/mock.rs
index b580b752bd9..b580b752bd9 100644
--- a/src/libcore/rt/io/mock.rs
+++ b/src/libstd/rt/io/mock.rs
diff --git a/src/libcore/rt/local.rs b/src/libstd/rt/local.rs
index 64a384ddff0..64a384ddff0 100644
--- a/src/libcore/rt/local.rs
+++ b/src/libstd/rt/local.rs
diff --git a/src/libcore/rt/local_ptr.rs b/src/libstd/rt/local_ptr.rs
index 80d797e8c65..80d797e8c65 100644
--- a/src/libcore/rt/local_ptr.rs
+++ b/src/libstd/rt/local_ptr.rs
diff --git a/src/libcore/rt/logging.rs b/src/libstd/rt/logging.rs
index a0d05397689..a0d05397689 100644
--- a/src/libcore/rt/logging.rs
+++ b/src/libstd/rt/logging.rs
diff --git a/src/libcore/rt/message_queue.rs b/src/libstd/rt/message_queue.rs
index eaab9288ac8..eaab9288ac8 100644
--- a/src/libcore/rt/message_queue.rs
+++ b/src/libstd/rt/message_queue.rs
diff --git a/src/libcore/rt/rc.rs b/src/libstd/rt/rc.rs
index 1c0c8c14fdf..1c0c8c14fdf 100644
--- a/src/libcore/rt/rc.rs
+++ b/src/libstd/rt/rc.rs
diff --git a/src/libcore/rt/sched.rs b/src/libstd/rt/sched.rs
index 50c6a894093..50c6a894093 100644
--- a/src/libcore/rt/sched.rs
+++ b/src/libstd/rt/sched.rs
diff --git a/src/libcore/rt/tube.rs b/src/libstd/rt/tube.rs
index b2f475a6966..b2f475a6966 100644
--- a/src/libcore/rt/tube.rs
+++ b/src/libstd/rt/tube.rs
diff --git a/src/libcore/rt/uv/idle.rs b/src/libstd/rt/uv/idle.rs
index 2cf0b5c4872..2cf0b5c4872 100644
--- a/src/libcore/rt/uv/idle.rs
+++ b/src/libstd/rt/uv/idle.rs
diff --git a/src/libcore/rt/uv/timer.rs b/src/libstd/rt/uv/timer.rs
index 5557a580987..5557a580987 100644
--- a/src/libcore/rt/uv/timer.rs
+++ b/src/libstd/rt/uv/timer.rs
diff --git a/src/libstd/rt/uv/uvio.rs b/src/libstd/rt/uv/uvio.rs
new file mode 100644
index 00000000000..cacd67314eb
--- /dev/null
+++ b/src/libstd/rt/uv/uvio.rs
@@ -0,0 +1,492 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use option::*;
+use result::*;
+use ops::Drop;
+use cell::{Cell, empty_cell};
+use cast::transmute;
+use clone::Clone;
+use rt::io::IoError;
+use rt::io::net::ip::IpAddr;
+use rt::uv::*;
+use rt::uv::idle::IdleWatcher;
+use rt::rtio::*;
+use rt::sched::Scheduler;
+use rt::io::{standard_error, OtherIoError};
+use rt::tube::Tube;
+use rt::local::Local;
+
+#[cfg(test)] use container::Container;
+#[cfg(test)] use uint;
+#[cfg(test)] use unstable::run_in_bare_thread;
+#[cfg(test)] use rt::test::*;
+
+pub struct UvEventLoop {
+    uvio: UvIoFactory
+}
+
+pub impl UvEventLoop {
+    fn new() -> UvEventLoop {
+        UvEventLoop {
+            uvio: UvIoFactory(Loop::new())
+        }
+    }
+
+    /// A convenience constructor
+    fn new_scheduler() -> Scheduler {
+        Scheduler::new(~UvEventLoop::new())
+    }
+}
+
+impl Drop for UvEventLoop {
+    fn finalize(&self) {
+        // XXX: Need mutable finalizer
+        let this = unsafe {
+            transmute::<&UvEventLoop, &mut UvEventLoop>(self)
+        };
+        this.uvio.uv_loop().close();
+    }
+}
+
+impl EventLoop for UvEventLoop {
+
+    fn run(&mut self) {
+        self.uvio.uv_loop().run();
+    }
+
+    fn callback(&mut self, f: ~fn()) {
+        let mut idle_watcher =  IdleWatcher::new(self.uvio.uv_loop());
+        do idle_watcher.start |idle_watcher, status| {
+            assert!(status.is_none());
+            let mut idle_watcher = idle_watcher;
+            idle_watcher.stop();
+            idle_watcher.close(||());
+            f();
+        }
+    }
+
+    fn callback_ms(&mut self, ms: u64, f: ~fn()) {
+        let mut timer =  TimerWatcher::new(self.uvio.uv_loop());
+        do timer.start(ms, 0) |timer, status| {
+            assert!(status.is_none());
+            timer.close(||());
+            f();
+        }
+    }
+
+    fn io<'a>(&'a mut self) -> Option<&'a mut IoFactoryObject> {
+        Some(&mut self.uvio)
+    }
+}
+
+#[test]
+fn test_callback_run_once() {
+    do run_in_bare_thread {
+        let mut event_loop = UvEventLoop::new();
+        let mut count = 0;
+        let count_ptr: *mut int = &mut count;
+        do event_loop.callback {
+            unsafe { *count_ptr += 1 }
+        }
+        event_loop.run();
+        assert_eq!(count, 1);
+    }
+}
+
+pub struct UvIoFactory(Loop);
+
+pub impl UvIoFactory {
+    fn uv_loop<'a>(&'a mut self) -> &'a mut Loop {
+        match self { &UvIoFactory(ref mut ptr) => ptr }
+    }
+}
+
+impl IoFactory for UvIoFactory {
+    // Connect to an address and return a new stream
+    // NB: This blocks the task waiting on the connection.
+    // It would probably be better to return a future
+    fn tcp_connect(&mut self, addr: IpAddr) -> Result<~RtioTcpStreamObject, IoError> {
+        // Create a cell in the task to hold the result. We will fill
+        // the cell before resuming the task.
+        let result_cell = empty_cell();
+        let result_cell_ptr: *Cell<Result<~RtioTcpStreamObject, IoError>> = &result_cell;
+
+        let scheduler = Local::take::<Scheduler>();
+        assert!(scheduler.in_task_context());
+
+        // Block this task and take ownership, switch to scheduler context
+        do scheduler.deschedule_running_task_and_then |task| {
+
+            rtdebug!("connect: entered scheduler context");
+            do Local::borrow::<Scheduler> |scheduler| {
+                assert!(!scheduler.in_task_context());
+            }
+            let mut tcp_watcher = TcpWatcher::new(self.uv_loop());
+            let task_cell = Cell(task);
+
+            // Wait for a connection
+            do tcp_watcher.connect(addr) |stream_watcher, status| {
+                rtdebug!("connect: in connect callback");
+                if status.is_none() {
+                    rtdebug!("status is none");
+                    let res = Ok(~UvTcpStream { watcher: stream_watcher });
+
+                    // Store the stream in the task's stack
+                    unsafe { (*result_cell_ptr).put_back(res); }
+
+                    // Context switch
+                    let scheduler = Local::take::<Scheduler>();
+                    scheduler.resume_task_immediately(task_cell.take());
+                } else {
+                    rtdebug!("status is some");
+                    let task_cell = Cell(task_cell.take());
+                    do stream_watcher.close {
+                        let res = Err(uv_error_to_io_error(status.get()));
+                        unsafe { (*result_cell_ptr).put_back(res); }
+                        let scheduler = Local::take::<Scheduler>();
+                        scheduler.resume_task_immediately(task_cell.take());
+                    }
+                };
+            }
+        }
+
+        assert!(!result_cell.is_empty());
+        return result_cell.take();
+    }
+
+    fn tcp_bind(&mut self, addr: IpAddr) -> Result<~RtioTcpListenerObject, IoError> {
+        let mut watcher = TcpWatcher::new(self.uv_loop());
+        match watcher.bind(addr) {
+            Ok(_) => Ok(~UvTcpListener::new(watcher)),
+            Err(uverr) => {
+                let scheduler = Local::take::<Scheduler>();
+                do scheduler.deschedule_running_task_and_then |task| {
+                    let task_cell = Cell(task);
+                    do watcher.as_stream().close {
+                        let scheduler = Local::take::<Scheduler>();
+                        scheduler.resume_task_immediately(task_cell.take());
+                    }
+                }
+                Err(uv_error_to_io_error(uverr))
+            }
+        }
+    }
+}
+
+// FIXME #6090: Prefer newtype structs but Drop doesn't work
+pub struct UvTcpListener {
+    watcher: TcpWatcher,
+    listening: bool,
+    incoming_streams: Tube<Result<~RtioTcpStreamObject, IoError>>
+}
+
+impl UvTcpListener {
+    fn new(watcher: TcpWatcher) -> UvTcpListener {
+        UvTcpListener {
+            watcher: watcher,
+            listening: false,
+            incoming_streams: Tube::new()
+        }
+    }
+
+    fn watcher(&self) -> TcpWatcher { self.watcher }
+}
+
+impl Drop for UvTcpListener {
+    fn finalize(&self) {
+        let watcher = self.watcher();
+        let scheduler = Local::take::<Scheduler>();
+        do scheduler.deschedule_running_task_and_then |task| {
+            let task_cell = Cell(task);
+            do watcher.as_stream().close {
+                let scheduler = Local::take::<Scheduler>();
+                scheduler.resume_task_immediately(task_cell.take());
+            }
+        }
+    }
+}
+
+impl RtioTcpListener for UvTcpListener {
+
+    fn accept(&mut self) -> Result<~RtioTcpStreamObject, IoError> {
+        rtdebug!("entering listen");
+
+        if self.listening {
+            return self.incoming_streams.recv();
+        }
+
+        self.listening = true;
+
+        let server_tcp_watcher = self.watcher();
+        let incoming_streams_cell = Cell(self.incoming_streams.clone());
+
+        let incoming_streams_cell = Cell(incoming_streams_cell.take());
+        let mut server_tcp_watcher = server_tcp_watcher;
+        do server_tcp_watcher.listen |server_stream_watcher, status| {
+            let maybe_stream = if status.is_none() {
+                let mut server_stream_watcher = server_stream_watcher;
+                let mut loop_ = server_stream_watcher.event_loop();
+                let client_tcp_watcher = TcpWatcher::new(&mut loop_);
+                let client_tcp_watcher = client_tcp_watcher.as_stream();
+                // XXX: Need's to be surfaced in interface
+                server_stream_watcher.accept(client_tcp_watcher);
+                Ok(~UvTcpStream { watcher: client_tcp_watcher })
+            } else {
+                Err(standard_error(OtherIoError))
+            };
+
+            let mut incoming_streams = incoming_streams_cell.take();
+            incoming_streams.send(maybe_stream);
+            incoming_streams_cell.put_back(incoming_streams);
+        }
+
+        return self.incoming_streams.recv();
+    }
+}
+
+// FIXME #6090: Prefer newtype structs but Drop doesn't work
+pub struct UvTcpStream {
+    watcher: StreamWatcher
+}
+
+impl UvTcpStream {
+    fn watcher(&self) -> StreamWatcher { self.watcher }
+}
+
+impl Drop for UvTcpStream {
+    fn finalize(&self) {
+        rtdebug!("closing tcp stream");
+        let watcher = self.watcher();
+        let scheduler = Local::take::<Scheduler>();
+        do scheduler.deschedule_running_task_and_then |task| {
+            let task_cell = Cell(task);
+            do watcher.close {
+                let scheduler = Local::take::<Scheduler>();
+                scheduler.resume_task_immediately(task_cell.take());
+            }
+        }
+    }
+}
+
+impl RtioTcpStream for UvTcpStream {
+    fn read(&mut self, buf: &mut [u8]) -> Result<uint, IoError> {
+        let result_cell = empty_cell();
+        let result_cell_ptr: *Cell<Result<uint, IoError>> = &result_cell;
+
+        let scheduler = Local::take::<Scheduler>();
+        assert!(scheduler.in_task_context());
+        let watcher = self.watcher();
+        let buf_ptr: *&mut [u8] = &buf;
+        do scheduler.deschedule_running_task_and_then |task| {
+            rtdebug!("read: entered scheduler context");
+            do Local::borrow::<Scheduler> |scheduler| {
+                assert!(!scheduler.in_task_context());
+            }
+            let mut watcher = watcher;
+            let task_cell = Cell(task);
+            // XXX: We shouldn't reallocate these callbacks every
+            // call to read
+            let alloc: AllocCallback = |_| unsafe {
+                slice_to_uv_buf(*buf_ptr)
+            };
+            do watcher.read_start(alloc) |watcher, nread, _buf, status| {
+
+                // Stop reading so that no read callbacks are
+                // triggered before the user calls `read` again.
+                // XXX: Is there a performance impact to calling
+                // stop here?
+                let mut watcher = watcher;
+                watcher.read_stop();
+
+                let result = if status.is_none() {
+                    assert!(nread >= 0);
+                    Ok(nread as uint)
+                } else {
+                    Err(uv_error_to_io_error(status.unwrap()))
+                };
+
+                unsafe { (*result_cell_ptr).put_back(result); }
+
+                let scheduler = Local::take::<Scheduler>();
+                scheduler.resume_task_immediately(task_cell.take());
+            }
+        }
+
+        assert!(!result_cell.is_empty());
+        return result_cell.take();
+    }
+
+    fn write(&mut self, buf: &[u8]) -> Result<(), IoError> {
+        let result_cell = empty_cell();
+        let result_cell_ptr: *Cell<Result<(), IoError>> = &result_cell;
+        let scheduler = Local::take::<Scheduler>();
+        assert!(scheduler.in_task_context());
+        let watcher = self.watcher();
+        let buf_ptr: *&[u8] = &buf;
+        do scheduler.deschedule_running_task_and_then |task| {
+            let mut watcher = watcher;
+            let task_cell = Cell(task);
+            let buf = unsafe { slice_to_uv_buf(*buf_ptr) };
+            do watcher.write(buf) |_watcher, status| {
+                let result = if status.is_none() {
+                    Ok(())
+                } else {
+                    Err(uv_error_to_io_error(status.unwrap()))
+                };
+
+                unsafe { (*result_cell_ptr).put_back(result); }
+
+                let scheduler = Local::take::<Scheduler>();
+                scheduler.resume_task_immediately(task_cell.take());
+            }
+        }
+
+        assert!(!result_cell.is_empty());
+        return result_cell.take();
+    }
+}
+
+#[test]
+fn test_simple_io_no_connect() {
+    do run_in_newsched_task {
+        unsafe {
+            let io = Local::unsafe_borrow::<IoFactoryObject>();
+            let addr = next_test_ip4();
+            let maybe_chan = (*io).tcp_connect(addr);
+            assert!(maybe_chan.is_err());
+        }
+    }
+}
+
+#[test]
+fn test_simple_tcp_server_and_client() {
+    do run_in_newsched_task {
+        let addr = next_test_ip4();
+
+        // Start the server first so it's listening when we connect
+        do spawntask_immediately {
+            unsafe {
+                let io = Local::unsafe_borrow::<IoFactoryObject>();
+                let mut listener = (*io).tcp_bind(addr).unwrap();
+                let mut stream = listener.accept().unwrap();
+                let mut buf = [0, .. 2048];
+                let nread = stream.read(buf).unwrap();
+                assert_eq!(nread, 8);
+                for uint::range(0, nread) |i| {
+                    rtdebug!("%u", buf[i] as uint);
+                    assert_eq!(buf[i], i as u8);
+                }
+            }
+        }
+
+        do spawntask_immediately {
+            unsafe {
+                let io = Local::unsafe_borrow::<IoFactoryObject>();
+                let mut stream = (*io).tcp_connect(addr).unwrap();
+                stream.write([0, 1, 2, 3, 4, 5, 6, 7]);
+            }
+        }
+    }
+}
+
+#[test] #[ignore(reason = "busted")]
+fn test_read_and_block() {
+    do run_in_newsched_task {
+        let addr = next_test_ip4();
+
+        do spawntask_immediately {
+            let io = unsafe { Local::unsafe_borrow::<IoFactoryObject>() };
+            let mut listener = unsafe { (*io).tcp_bind(addr).unwrap() };
+            let mut stream = listener.accept().unwrap();
+            let mut buf = [0, .. 2048];
+
+            let expected = 32;
+            let mut current = 0;
+            let mut reads = 0;
+
+            while current < expected {
+                let nread = stream.read(buf).unwrap();
+                for uint::range(0, nread) |i| {
+                    let val = buf[i] as uint;
+                    assert_eq!(val, current % 8);
+                    current += 1;
+                }
+                reads += 1;
+
+                let scheduler = Local::take::<Scheduler>();
+                // Yield to the other task in hopes that it
+                // will trigger a read callback while we are
+                // not ready for it
+                do scheduler.deschedule_running_task_and_then |task| {
+                    let task = Cell(task);
+                    do Local::borrow::<Scheduler> |scheduler| {
+                        scheduler.enqueue_task(task.take());
+                    }
+                }
+            }
+
+            // Make sure we had multiple reads
+            assert!(reads > 1);
+        }
+
+        do spawntask_immediately {
+            unsafe {
+                let io = Local::unsafe_borrow::<IoFactoryObject>();
+                let mut stream = (*io).tcp_connect(addr).unwrap();
+                stream.write([0, 1, 2, 3, 4, 5, 6, 7]);
+                stream.write([0, 1, 2, 3, 4, 5, 6, 7]);
+                stream.write([0, 1, 2, 3, 4, 5, 6, 7]);
+                stream.write([0, 1, 2, 3, 4, 5, 6, 7]);
+            }
+        }
+
+    }
+}
+
+#[test]
+fn test_read_read_read() {
+    do run_in_newsched_task {
+        let addr = next_test_ip4();
+        static MAX: uint = 500000;
+
+        do spawntask_immediately {
+            unsafe {
+                let io = Local::unsafe_borrow::<IoFactoryObject>();
+                let mut listener = (*io).tcp_bind(addr).unwrap();
+                let mut stream = listener.accept().unwrap();
+                let buf = [1, .. 2048];
+                let mut total_bytes_written = 0;
+                while total_bytes_written < MAX {
+                    stream.write(buf);
+                    total_bytes_written += buf.len();
+                }
+            }
+        }
+
+        do spawntask_immediately {
+            unsafe {
+                let io = Local::unsafe_borrow::<IoFactoryObject>();
+                let mut stream = (*io).tcp_connect(addr).unwrap();
+                let mut buf = [0, .. 2048];
+                let mut total_bytes_read = 0;
+                while total_bytes_read < MAX {
+                    let nread = stream.read(buf).unwrap();
+                    rtdebug!("read %u bytes", nread as uint);
+                    total_bytes_read += nread;
+                    for uint::range(0, nread) |i| {
+                        assert_eq!(buf[i], 1);
+                    }
+                }
+                rtdebug!("read %u bytes total", total_bytes_read as uint);
+            }
+        }
+    }
+}
diff --git a/src/libstd/rt/uv/uvll.rs b/src/libstd/rt/uv/uvll.rs
new file mode 100644
index 00000000000..ddc9040d730
--- /dev/null
+++ b/src/libstd/rt/uv/uvll.rs
@@ -0,0 +1,452 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+/*!
+ * Low-level bindings to the libuv library.
+ *
+ * This module contains a set of direct, 'bare-metal' wrappers around
+ * the libuv C-API.
+ *
+ * We're not bothering yet to redefine uv's structs as Rust structs
+ * because they are quite large and change often between versions.
+ * The maintenance burden is just too high. Instead we use the uv's
+ * `uv_handle_size` and `uv_req_size` to find the correct size of the
+ * structs and allocate them on the heap. This can be revisited later.
+ *
+ * There are also a collection of helper functions to ease interacting
+ * with the low-level API.
+ *
+ * As new functionality, existant in uv.h, is added to the rust stdlib,
+ * the mappings should be added in this module.
+ */
+
+#[allow(non_camel_case_types)]; // C types
+
+use libc::{size_t, c_int, c_uint, c_void, c_char, uintptr_t};
+use libc::{malloc, free};
+use prelude::*;
+
+pub static UNKNOWN: c_int = -1;
+pub static OK: c_int = 0;
+pub static EOF: c_int = 1;
+pub static EADDRINFO: c_int = 2;
+pub static EACCES: c_int = 3;
+pub static ECONNREFUSED: c_int = 12;
+pub static ECONNRESET: c_int = 13;
+pub static EPIPE: c_int = 36;
+
+pub struct uv_err_t {
+    code: c_int,
+    sys_errno_: c_int
+}
+
+pub struct uv_buf_t {
+    base: *u8,
+    len: libc::size_t,
+}
+
+pub type uv_handle_t = c_void;
+pub type uv_loop_t = c_void;
+pub type uv_idle_t = c_void;
+pub type uv_tcp_t = c_void;
+pub type uv_connect_t = c_void;
+pub type uv_write_t = c_void;
+pub type uv_async_t = c_void;
+pub type uv_timer_t = c_void;
+pub type uv_stream_t = c_void;
+pub type uv_fs_t = c_void;
+
+pub type uv_idle_cb = *u8;
+
+pub type sockaddr_in = c_void;
+pub type sockaddr_in6 = c_void;
+
+#[deriving(Eq)]
+pub enum uv_handle_type {
+    UV_UNKNOWN_HANDLE,
+    UV_ASYNC,
+    UV_CHECK,
+    UV_FS_EVENT,
+    UV_FS_POLL,
+    UV_HANDLE,
+    UV_IDLE,
+    UV_NAMED_PIPE,
+    UV_POLL,
+    UV_PREPARE,
+    UV_PROCESS,
+    UV_STREAM,
+    UV_TCP,
+    UV_TIMER,
+    UV_TTY,
+    UV_UDP,
+    UV_SIGNAL,
+    UV_FILE,
+    UV_HANDLE_TYPE_MAX
+}
+
+#[deriving(Eq)]
+pub enum uv_req_type {
+    UV_UNKNOWN_REQ,
+    UV_REQ,
+    UV_CONNECT,
+    UV_WRITE,
+    UV_SHUTDOWN,
+    UV_UDP_SEND,
+    UV_FS,
+    UV_WORK,
+    UV_GETADDRINFO,
+    UV_REQ_TYPE_MAX
+}
+
+pub unsafe fn malloc_handle(handle: uv_handle_type) -> *c_void {
+    assert!(handle != UV_UNKNOWN_HANDLE && handle != UV_HANDLE_TYPE_MAX);
+    let size = rust_uv_handle_size(handle as uint);
+    let p = malloc(size);
+    assert!(p.is_not_null());
+    return p;
+}
+
+pub unsafe fn free_handle(v: *c_void) {
+    free(v)
+}
+
+pub unsafe fn malloc_req(req: uv_req_type) -> *c_void {
+    assert!(req != UV_UNKNOWN_REQ && req != UV_REQ_TYPE_MAX);
+    let size = rust_uv_req_size(req as uint);
+    let p = malloc(size);
+    assert!(p.is_not_null());
+    return p;
+}
+
+pub unsafe fn free_req(v: *c_void) {
+    free(v)
+}
+
+#[test]
+fn handle_sanity_check() {
+    unsafe {
+        assert_eq!(UV_HANDLE_TYPE_MAX as uint, rust_uv_handle_type_max());
+    }
+}
+
+#[test]
+fn request_sanity_check() {
+    unsafe {
+        assert_eq!(UV_REQ_TYPE_MAX as uint, rust_uv_req_type_max());
+    }
+}
+
+pub unsafe fn loop_new() -> *c_void {
+    return rust_uv_loop_new();
+}
+
+pub unsafe fn loop_delete(loop_handle: *c_void) {
+    rust_uv_loop_delete(loop_handle);
+}
+
+pub unsafe fn run(loop_handle: *c_void) {
+    rust_uv_run(loop_handle);
+}
+
+pub unsafe fn close<T>(handle: *T, cb: *u8) {
+    rust_uv_close(handle as *c_void, cb);
+}
+
+pub unsafe fn walk(loop_handle: *c_void, cb: *u8, arg: *c_void) {
+    rust_uv_walk(loop_handle, cb, arg);
+}
+
+pub unsafe fn idle_new() -> *uv_idle_t {
+    rust_uv_idle_new()
+}
+
+pub unsafe fn idle_delete(handle: *uv_idle_t) {
+    rust_uv_idle_delete(handle)
+}
+
+pub unsafe fn idle_init(loop_handle: *uv_loop_t, handle: *uv_idle_t) -> c_int {
+    rust_uv_idle_init(loop_handle, handle)
+}
+
+pub unsafe fn idle_start(handle: *uv_idle_t, cb: uv_idle_cb) -> c_int {
+    rust_uv_idle_start(handle, cb)
+}
+
+pub unsafe fn idle_stop(handle: *uv_idle_t) -> c_int {
+    rust_uv_idle_stop(handle)
+}
+
+pub unsafe fn tcp_init(loop_handle: *c_void, handle: *uv_tcp_t) -> c_int {
+    return rust_uv_tcp_init(loop_handle, handle);
+}
+
+// FIXME ref #2064
+pub unsafe fn tcp_connect(connect_ptr: *uv_connect_t,
+                          tcp_handle_ptr: *uv_tcp_t,
+                          addr_ptr: *sockaddr_in,
+                          after_connect_cb: *u8) -> c_int {
+    return rust_uv_tcp_connect(connect_ptr, tcp_handle_ptr,
+                                       after_connect_cb, addr_ptr);
+}
+// FIXME ref #2064
+pub unsafe fn tcp_connect6(connect_ptr: *uv_connect_t,
+                           tcp_handle_ptr: *uv_tcp_t,
+                           addr_ptr: *sockaddr_in6,
+                           after_connect_cb: *u8) -> c_int {
+    return rust_uv_tcp_connect6(connect_ptr, tcp_handle_ptr,
+                                        after_connect_cb, addr_ptr);
+}
+// FIXME ref #2064
+pub unsafe fn tcp_bind(tcp_server_ptr: *uv_tcp_t, addr_ptr: *sockaddr_in) -> c_int {
+    return rust_uv_tcp_bind(tcp_server_ptr, addr_ptr);
+}
+// FIXME ref #2064
+pub unsafe fn tcp_bind6(tcp_server_ptr: *uv_tcp_t, addr_ptr: *sockaddr_in6) -> c_int {
+    return rust_uv_tcp_bind6(tcp_server_ptr, addr_ptr);
+}
+
+pub unsafe fn tcp_getpeername(tcp_handle_ptr: *uv_tcp_t, name: *sockaddr_in) -> c_int {
+    return rust_uv_tcp_getpeername(tcp_handle_ptr, name);
+}
+
+pub unsafe fn tcp_getpeername6(tcp_handle_ptr: *uv_tcp_t, name: *sockaddr_in6) ->c_int {
+    return rust_uv_tcp_getpeername6(tcp_handle_ptr, name);
+}
+
+pub unsafe fn listen<T>(stream: *T, backlog: c_int, cb: *u8) -> c_int {
+    return rust_uv_listen(stream as *c_void, backlog, cb);
+}
+
+pub unsafe fn accept(server: *c_void, client: *c_void) -> c_int {
+    return rust_uv_accept(server as *c_void, client as *c_void);
+}
+
+pub unsafe fn write<T>(req: *uv_write_t, stream: *T, buf_in: &[uv_buf_t], cb: *u8) -> c_int {
+    let buf_ptr = vec::raw::to_ptr(buf_in);
+    let buf_cnt = buf_in.len() as i32;
+    return rust_uv_write(req as *c_void, stream as *c_void, buf_ptr, buf_cnt, cb);
+}
+pub unsafe fn read_start(stream: *uv_stream_t, on_alloc: *u8, on_read: *u8) -> c_int {
+    return rust_uv_read_start(stream as *c_void, on_alloc, on_read);
+}
+
+pub unsafe fn read_stop(stream: *uv_stream_t) -> c_int {
+    return rust_uv_read_stop(stream as *c_void);
+}
+
+pub unsafe fn last_error(loop_handle: *c_void) -> uv_err_t {
+    return rust_uv_last_error(loop_handle);
+}
+
+pub unsafe fn strerror(err: *uv_err_t) -> *c_char {
+    return rust_uv_strerror(err);
+}
+pub unsafe fn err_name(err: *uv_err_t) -> *c_char {
+    return rust_uv_err_name(err);
+}
+
+pub unsafe fn async_init(loop_handle: *c_void, async_handle: *uv_async_t, cb: *u8) -> c_int {
+    return rust_uv_async_init(loop_handle, async_handle, cb);
+}
+
+pub unsafe fn async_send(async_handle: *uv_async_t) {
+    return rust_uv_async_send(async_handle);
+}
+pub unsafe fn buf_init(input: *u8, len: uint) -> uv_buf_t {
+    let out_buf = uv_buf_t { base: ptr::null(), len: 0 as size_t };
+    let out_buf_ptr = ptr::to_unsafe_ptr(&out_buf);
+    rust_uv_buf_init(out_buf_ptr, input, len as size_t);
+    return out_buf;
+}
+
+pub unsafe fn timer_init(loop_ptr: *c_void, timer_ptr: *uv_timer_t) -> c_int {
+    return rust_uv_timer_init(loop_ptr, timer_ptr);
+}
+pub unsafe fn timer_start(timer_ptr: *uv_timer_t, cb: *u8, timeout: u64,
+                          repeat: u64) -> c_int {
+    return rust_uv_timer_start(timer_ptr, cb, timeout, repeat);
+}
+pub unsafe fn timer_stop(timer_ptr: *uv_timer_t) -> c_int {
+    return rust_uv_timer_stop(timer_ptr);
+}
+
+pub unsafe fn malloc_ip4_addr(ip: &str, port: int) -> *sockaddr_in {
+    do str::as_c_str(ip) |ip_buf| {
+        rust_uv_ip4_addrp(ip_buf as *u8, port as libc::c_int)
+    }
+}
+pub unsafe fn malloc_ip6_addr(ip: &str, port: int) -> *sockaddr_in6 {
+    do str::as_c_str(ip) |ip_buf| {
+        rust_uv_ip6_addrp(ip_buf as *u8, port as libc::c_int)
+    }
+}
+
+pub unsafe fn free_ip4_addr(addr: *sockaddr_in) {
+    rust_uv_free_ip4_addr(addr);
+}
+
+pub unsafe fn free_ip6_addr(addr: *sockaddr_in6) {
+    rust_uv_free_ip6_addr(addr);
+}
+
+// data access helpers
+pub unsafe fn get_loop_for_uv_handle<T>(handle: *T) -> *c_void {
+    return rust_uv_get_loop_for_uv_handle(handle as *c_void);
+}
+pub unsafe fn get_stream_handle_from_connect_req(connect: *uv_connect_t) -> *uv_stream_t {
+    return rust_uv_get_stream_handle_from_connect_req(connect);
+}
+pub unsafe fn get_stream_handle_from_write_req(write_req: *uv_write_t) -> *uv_stream_t {
+    return rust_uv_get_stream_handle_from_write_req(write_req);
+}
+pub unsafe fn get_data_for_uv_loop(loop_ptr: *c_void) -> *c_void {
+    rust_uv_get_data_for_uv_loop(loop_ptr)
+}
+pub unsafe fn set_data_for_uv_loop(loop_ptr: *c_void, data: *c_void) {
+    rust_uv_set_data_for_uv_loop(loop_ptr, data);
+}
+pub unsafe fn get_data_for_uv_handle<T>(handle: *T) -> *c_void {
+    return rust_uv_get_data_for_uv_handle(handle as *c_void);
+}
+pub unsafe fn set_data_for_uv_handle<T, U>(handle: *T, data: *U) {
+    rust_uv_set_data_for_uv_handle(handle as *c_void, data as *c_void);
+}
+pub unsafe fn get_data_for_req<T>(req: *T) -> *c_void {
+    return rust_uv_get_data_for_req(req as *c_void);
+}
+pub unsafe fn set_data_for_req<T, U>(req: *T, data: *U) {
+    rust_uv_set_data_for_req(req as *c_void, data as *c_void);
+}
+pub unsafe fn get_base_from_buf(buf: uv_buf_t) -> *u8 {
+    return rust_uv_get_base_from_buf(buf);
+}
+pub unsafe fn get_len_from_buf(buf: uv_buf_t) -> size_t {
+    return rust_uv_get_len_from_buf(buf);
+}
+pub unsafe fn malloc_buf_base_of(suggested_size: size_t) -> *u8 {
+    return rust_uv_malloc_buf_base_of(suggested_size);
+}
+pub unsafe fn free_base_of_buf(buf: uv_buf_t) {
+    rust_uv_free_base_of_buf(buf);
+}
+
+pub unsafe fn get_last_err_info(uv_loop: *c_void) -> ~str {
+    let err = last_error(uv_loop);
+    let err_ptr = ptr::to_unsafe_ptr(&err);
+    let err_name = str::raw::from_c_str(err_name(err_ptr));
+    let err_msg = str::raw::from_c_str(strerror(err_ptr));
+    return fmt!("LIBUV ERROR: name: %s msg: %s",
+                    err_name, err_msg);
+}
+
+pub unsafe fn get_last_err_data(uv_loop: *c_void) -> uv_err_data {
+    let err = last_error(uv_loop);
+    let err_ptr = ptr::to_unsafe_ptr(&err);
+    let err_name = str::raw::from_c_str(err_name(err_ptr));
+    let err_msg = str::raw::from_c_str(strerror(err_ptr));
+    uv_err_data { err_name: err_name, err_msg: err_msg }
+}
+
+pub struct uv_err_data {
+    err_name: ~str,
+    err_msg: ~str,
+}
+
+extern {
+
+    fn rust_uv_handle_size(type_: uintptr_t) -> size_t;
+    fn rust_uv_req_size(type_: uintptr_t) -> size_t;
+    fn rust_uv_handle_type_max() -> uintptr_t;
+    fn rust_uv_req_type_max() -> uintptr_t;
+
+    // libuv public API
+    fn rust_uv_loop_new() -> *c_void;
+    fn rust_uv_loop_delete(lp: *c_void);
+    fn rust_uv_run(loop_handle: *c_void);
+    fn rust_uv_close(handle: *c_void, cb: *u8);
+    fn rust_uv_walk(loop_handle: *c_void, cb: *u8, arg: *c_void);
+
+    fn rust_uv_idle_new() -> *uv_idle_t;
+    fn rust_uv_idle_delete(handle: *uv_idle_t);
+    fn rust_uv_idle_init(loop_handle: *uv_loop_t, handle: *uv_idle_t) -> c_int;
+    fn rust_uv_idle_start(handle: *uv_idle_t, cb: uv_idle_cb) -> c_int;
+    fn rust_uv_idle_stop(handle: *uv_idle_t) -> c_int;
+
+    fn rust_uv_async_send(handle: *uv_async_t);
+    fn rust_uv_async_init(loop_handle: *c_void,
+                          async_handle: *uv_async_t,
+                          cb: *u8) -> c_int;
+    fn rust_uv_tcp_init(loop_handle: *c_void, handle_ptr: *uv_tcp_t) -> c_int;
+    // FIXME ref #2604 .. ?
+    fn rust_uv_buf_init(out_buf: *uv_buf_t, base: *u8, len: size_t);
+    fn rust_uv_last_error(loop_handle: *c_void) -> uv_err_t;
+    // FIXME ref #2064
+    fn rust_uv_strerror(err: *uv_err_t) -> *c_char;
+    // FIXME ref #2064
+    fn rust_uv_err_name(err: *uv_err_t) -> *c_char;
+    fn rust_uv_ip4_addrp(ip: *u8, port: c_int) -> *sockaddr_in;
+    fn rust_uv_ip6_addrp(ip: *u8, port: c_int) -> *sockaddr_in6;
+    fn rust_uv_free_ip4_addr(addr: *sockaddr_in);
+    fn rust_uv_free_ip6_addr(addr: *sockaddr_in6);
+    fn rust_uv_ip4_name(src: *sockaddr_in, dst: *u8, size: size_t) -> c_int;
+    fn rust_uv_ip6_name(src: *sockaddr_in6, dst: *u8, size: size_t) -> c_int;
+    fn rust_uv_ip4_port(src: *sockaddr_in) -> c_uint;
+    fn rust_uv_ip6_port(src: *sockaddr_in6) -> c_uint;
+    // FIXME ref #2064
+    fn rust_uv_tcp_connect(connect_ptr: *uv_connect_t,
+                           tcp_handle_ptr: *uv_tcp_t,
+                           after_cb: *u8,
+                           addr: *sockaddr_in) -> c_int;
+    // FIXME ref #2064
+    fn rust_uv_tcp_bind(tcp_server: *uv_tcp_t, addr: *sockaddr_in) -> c_int;
+    // FIXME ref #2064
+    fn rust_uv_tcp_connect6(connect_ptr: *uv_connect_t,
+                            tcp_handle_ptr: *uv_tcp_t,
+                            after_cb: *u8,
+                            addr: *sockaddr_in6) -> c_int;
+    // FIXME ref #2064
+    fn rust_uv_tcp_bind6(tcp_server: *uv_tcp_t, addr: *sockaddr_in6) -> c_int;
+    fn rust_uv_tcp_getpeername(tcp_handle_ptr: *uv_tcp_t,
+                               name: *sockaddr_in) -> c_int;
+    fn rust_uv_tcp_getpeername6(tcp_handle_ptr: *uv_tcp_t,
+                                name: *sockaddr_in6) ->c_int;
+    fn rust_uv_listen(stream: *c_void, backlog: c_int, cb: *u8) -> c_int;
+    fn rust_uv_accept(server: *c_void, client: *c_void) -> c_int;
+    fn rust_uv_write(req: *c_void,
+                     stream: *c_void,
+                     buf_in: *uv_buf_t,
+                     buf_cnt: c_int,
+                     cb: *u8) -> c_int;
+    fn rust_uv_read_start(stream: *c_void,
+                          on_alloc: *u8,
+                          on_read: *u8) -> c_int;
+    fn rust_uv_read_stop(stream: *c_void) -> c_int;
+    fn rust_uv_timer_init(loop_handle: *c_void,
+                          timer_handle: *uv_timer_t) -> c_int;
+    fn rust_uv_timer_start(timer_handle: *uv_timer_t,
+                           cb: *u8,
+                           timeout: libc::uint64_t,
+                           repeat: libc::uint64_t) -> c_int;
+    fn rust_uv_timer_stop(handle: *uv_timer_t) -> c_int;
+
+    fn rust_uv_malloc_buf_base_of(sug_size: size_t) -> *u8;
+    fn rust_uv_free_base_of_buf(buf: uv_buf_t);
+    fn rust_uv_get_stream_handle_from_connect_req(connect_req: *uv_connect_t) -> *uv_stream_t;
+    fn rust_uv_get_stream_handle_from_write_req(write_req: *uv_write_t) -> *uv_stream_t;
+    fn rust_uv_get_loop_for_uv_handle(handle: *c_void) -> *c_void;
+    fn rust_uv_get_data_for_uv_loop(loop_ptr: *c_void) -> *c_void;
+    fn rust_uv_set_data_for_uv_loop(loop_ptr: *c_void, data: *c_void);
+    fn rust_uv_get_data_for_uv_handle(handle: *c_void) -> *c_void;
+    fn rust_uv_set_data_for_uv_handle(handle: *c_void, data: *c_void);
+    fn rust_uv_get_data_for_req(req: *c_void) -> *c_void;
+    fn rust_uv_set_data_for_req(req: *c_void, data: *c_void);
+    fn rust_uv_get_base_from_buf(buf: uv_buf_t) -> *u8;
+    fn rust_uv_get_len_from_buf(buf: uv_buf_t) -> size_t;
+}
diff --git a/src/libsyntax/opt_vec.rs b/src/libsyntax/opt_vec.rs
index e3f1e9e1328..791f7444b62 100644
--- a/src/libsyntax/opt_vec.rs
+++ b/src/libsyntax/opt_vec.rs
@@ -16,6 +16,8 @@
  * other useful things like `push()` and `len()`.
  */
 
+use core::prelude::*;
+
 use core::old_iter;
 use core::old_iter::BaseIter;