diff --git a/src/libstd/cell.rs b/src/libcore/cell.rs
similarity index 98%
rename from src/libstd/cell.rs
rename to src/libcore/cell.rs
index c8121daddabd0..5887df6802f57 100644
--- a/src/libstd/cell.rs
+++ b/src/libcore/cell.rs
@@ -8,8 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use core::option;
-use core::prelude::*;
+use option;
+use prelude::*;
 
 /// A dynamic, mutable location.
 ///
diff --git a/src/libcore/core.rc b/src/libcore/core.rc
index 829651ae90925..ed18388f5783b 100644
--- a/src/libcore/core.rc
+++ b/src/libcore/core.rc
@@ -143,6 +143,7 @@ pub mod dlist;
 #[path="iter-trait.rs"] #[merge = "iter-trait/dlist.rs"]
 pub mod dlist_iter;
 pub mod hashmap;
+pub mod cell;
 
 
 /* Tasks and communication */
diff --git a/src/libcore/pipes.rs b/src/libcore/pipes.rs
index 94c0a567f4c09..15a6e700ffd84 100644
--- a/src/libcore/pipes.rs
+++ b/src/libcore/pipes.rs
@@ -86,6 +86,7 @@ bounded and unbounded protocols allows for less code duplication.
 
 use cmp::Eq;
 use cast::{forget, reinterpret_cast, transmute};
+use cell::Cell;
 use either::{Either, Left, Right};
 use kinds::Owned;
 use libc;
@@ -917,11 +918,9 @@ pub fn spawn_service<T:Owned,Tb:Owned>(
 
     // This is some nasty gymnastics required to safely move the pipe
     // into a new task.
-    let server = ~mut Some(server);
-    do task::spawn || {
-        let mut server_ = None;
-        server_ <-> *server;
-        service(option::unwrap(server_))
+    let server = Cell(server);
+    do task::spawn {
+        service(server.take());
     }
 
     client
@@ -941,11 +940,9 @@ pub fn spawn_service_recv<T:Owned,Tb:Owned>(
 
     // This is some nasty gymnastics required to safely move the pipe
     // into a new task.
-    let server = ~mut Some(server);
-    do task::spawn || {
-        let mut server_ = None;
-        server_ <-> *server;
-        service(option::unwrap(server_))
+    let server = Cell(server);
+    do task::spawn {
+        service(server.take())
     }
 
     client
diff --git a/src/libcore/private.rs b/src/libcore/private.rs
index 280eb14b172c4..d40f59fe673bf 100644
--- a/src/libcore/private.rs
+++ b/src/libcore/private.rs
@@ -107,10 +107,14 @@ fn compare_and_swap(address: &mut int, oldval: int, newval: int) -> bool {
  * Shared state & exclusive ARC
  ****************************************************************************/
 
+struct UnwrapProtoInner {
+    contents: Option<(comm::ChanOne<()>,  comm::PortOne<bool>)>,
+}
+
 // An unwrapper uses this protocol to communicate with the "other" task that
 // drops the last refcount on an arc. Unfortunately this can't be a proper
 // pipe protocol because the unwrapper has to access both stages at once.
-type UnwrapProto = ~mut Option<(comm::ChanOne<()>,  comm::PortOne<bool>)>;
+type UnwrapProto = ~UnwrapProtoInner;
 
 struct ArcData<T> {
     mut count:     libc::intptr_t,
@@ -139,9 +143,10 @@ struct ArcDestruct<T> {
                     // reference. In effect, being here means we're the only
                     // *awake* task with the data.
                     if data.unwrapper != 0 {
-                        let p: UnwrapProto =
+                        let mut p: UnwrapProto =
                             cast::reinterpret_cast(&data.unwrapper);
-                        let (message, response) = option::swap_unwrap(p);
+                        let (message, response) =
+                            option::swap_unwrap(&mut p.contents);
                         // Send 'ready' and wait for a response.
                         comm::send_one(message, ());
                         // Unkillable wait. Message guaranteed to come.
@@ -196,7 +201,9 @@ pub unsafe fn unwrap_shared_mutable_state<T:Owned>(rc: SharedMutableState<T>)
         let ptr: ~ArcData<T> = cast::reinterpret_cast(&rc.data);
         let (p1,c1) = comm::oneshot(); // ()
         let (p2,c2) = comm::oneshot(); // bool
-        let server: UnwrapProto = ~mut Some((c1,p2));
+        let mut server: UnwrapProto = ~UnwrapProtoInner {
+            contents: Some((c1,p2))
+        };
         let serverp: int = cast::transmute(server);
         // Try to put our server end in the unwrapper slot.
         if compare_and_swap(&mut ptr.unwrapper, 0, serverp) {
@@ -409,8 +416,9 @@ pub fn unwrap_exclusive<T:Owned>(arc: Exclusive<T>) -> T {
 pub mod tests {
     use core::option::{None, Some};
 
-    use option;
+    use cell::Cell;
     use comm;
+    use option;
     use private::{exclusive, unwrap_exclusive};
     use result;
     use task;
@@ -423,7 +431,7 @@ pub mod tests {
         let num_tasks = 10;
         let count = 10;
 
-        let total = exclusive(~mut 0);
+        let total = exclusive(~0);
 
         for uint::range(0, num_tasks) |_i| {
             let total = total.clone();
@@ -472,9 +480,9 @@ pub mod tests {
     #[test]
     pub fn exclusive_unwrap_contended() {
         let x = exclusive(~~"hello");
-        let x2 = ~mut Some(x.clone());
-        do task::spawn || {
-            let x2 = option::swap_unwrap(x2);
+        let x2 = Cell(x.clone());
+        do task::spawn {
+            let x2 = option::swap_unwrap(x2.take());
             do x2.with |_hello| { }
             task::yield();
         }
@@ -482,11 +490,10 @@ pub mod tests {
 
         // Now try the same thing, but with the child task blocking.
         let x = exclusive(~~"hello");
-        let x2 = ~mut Some(x.clone());
+        let x2 = Cell(x.clone());
         let mut res = None;
-        do task::task().future_result(|+r| res = Some(r)).spawn
-              || {
-            let x2 = option::swap_unwrap(x2);
+        do task::task().future_result(|+r| res = Some(r)).spawn {
+            let x2 = x2.take();
             assert unwrap_exclusive(x2) == ~~"hello";
         }
         // Have to get rid of our reference before blocking.
@@ -498,11 +505,10 @@ pub mod tests {
     #[test] #[should_fail] #[ignore(cfg(windows))]
     pub fn exclusive_unwrap_conflict() {
         let x = exclusive(~~"hello");
-        let x2 = ~mut Some(x.clone());
+        let x2 = Cell(x.clone());
         let mut res = None;
-        do task::task().future_result(|+r| res = Some(r)).spawn
-           || {
-            let x2 = option::swap_unwrap(x2);
+        do task::task().future_result(|+r| res = Some(r)).spawn {
+            let x2 = x2.take();
             assert unwrap_exclusive(x2) == ~~"hello";
         }
         assert unwrap_exclusive(x) == ~~"hello";
diff --git a/src/libcore/private/weak_task.rs b/src/libcore/private/weak_task.rs
index f3df8ce72f146..8445638850cd0 100644
--- a/src/libcore/private/weak_task.rs
+++ b/src/libcore/private/weak_task.rs
@@ -18,16 +18,17 @@ it is running, sending a notification to the task that the runtime
 is trying to shut down.
 */
 
+use cell::Cell;
+use comm::{GenericSmartChan, stream};
+use comm::{Port, Chan, SharedChan, GenericChan, GenericPort};
+use hashmap::linear::LinearMap;
+use ops::Drop;
 use option::{Some, None, swap_unwrap};
 use private::at_exit::at_exit;
-use private::global::global_data_clone_create;
 use private::finally::Finally;
-use comm::{Port, Chan, SharedChan, GenericChan,
-           GenericPort, GenericSmartChan, stream};
-use task::{Task, task, spawn};
+use private::global::global_data_clone_create;
 use task::rt::{task_id, get_task_id};
-use hashmap::linear::LinearMap;
-use ops::Drop;
+use task::{Task, task, spawn};
 
 type ShutdownMsg = ();
 
@@ -37,14 +38,13 @@ pub unsafe fn weaken_task(f: &fn(Port<ShutdownMsg>)) {
     let service = global_data_clone_create(global_data_key,
                                            create_global_service);
     let (shutdown_port, shutdown_chan) = stream::<ShutdownMsg>();
-    let shutdown_port = ~mut Some(shutdown_port);
+    let shutdown_port = Cell(shutdown_port);
     let task = get_task_id();
     // Expect the weak task service to be alive
     assert service.try_send(RegisterWeakTask(task, shutdown_chan));
     unsafe { rust_dec_kernel_live_count(); }
     do fn&() {
-        let shutdown_port = swap_unwrap(&mut *shutdown_port);
-        f(shutdown_port)
+        f(shutdown_port.take())
     }.finally || {
         unsafe { rust_inc_kernel_live_count(); }
         // Service my have already exited
@@ -67,16 +67,15 @@ fn create_global_service() -> ~WeakTaskService {
 
     debug!("creating global weak task service");
     let (port, chan) = stream::<ServiceMsg>();
-    let port = ~mut Some(port);
+    let port = Cell(port);
     let chan = SharedChan(chan);
     let chan_clone = chan.clone();
 
     do task().unlinked().spawn {
         debug!("running global weak task service");
-        let port = swap_unwrap(&mut *port);
-        let port = ~mut Some(port);
+        let port = Cell(port.take());
         do fn&() {
-            let port = swap_unwrap(&mut *port);
+            let port = port.take();
             // The weak task service is itself a weak task
             debug!("weakening the weak service task");
             unsafe { rust_dec_kernel_live_count(); }
diff --git a/src/libcore/repr.rs b/src/libcore/repr.rs
index 7f1687b08608a..4c3abb09756e9 100644
--- a/src/libcore/repr.rs
+++ b/src/libcore/repr.rs
@@ -602,7 +602,6 @@ fn test_repr() {
     exact_test(&(@10), "@10");
     exact_test(&(@mut 10), "@10");
     exact_test(&(~10), "~10");
-    exact_test(&(~mut 10), "~mut 10");
     exact_test(&(&10), "&10");
     let mut x = 10;
     exact_test(&(&mut x), "&mut 10");
diff --git a/src/libcore/task/mod.rs b/src/libcore/task/mod.rs
index 336e686193b91..2a640e4bf8cf7 100644
--- a/src/libcore/task/mod.rs
+++ b/src/libcore/task/mod.rs
@@ -34,6 +34,7 @@
  */
 
 use cast;
+use cell::Cell;
 use cmp;
 use cmp::Eq;
 use iter;
@@ -397,9 +398,9 @@ impl TaskBuilder {
     }
     /// Runs a task, while transfering ownership of one argument to the child.
     fn spawn_with<A:Owned>(arg: A, f: fn~(v: A)) {
-        let arg = ~mut Some(arg);
-        do self.spawn || {
-            f(option::swap_unwrap(arg))
+        let arg = Cell(arg);
+        do self.spawn {
+            f(arg.take());
         }
     }
 
diff --git a/src/libcore/task/spawn.rs b/src/libcore/task/spawn.rs
index e77af820079b6..5110f70ff11be 100644
--- a/src/libcore/task/spawn.rs
+++ b/src/libcore/task/spawn.rs
@@ -73,6 +73,7 @@
 #[doc(hidden)]; // FIXME #3538
 
 use cast;
+use cell::Cell;
 use container::Map;
 use option;
 use comm::{Chan, GenericChan, GenericPort, Port, stream};
@@ -530,11 +531,11 @@ pub fn spawn_raw(opts: TaskOpts, f: fn~()) {
         gen_child_taskgroup(opts.linked, opts.supervised);
 
     unsafe {
-        let child_data = ~mut Some((child_tg, ancestors, f));
+        let child_data = Cell((child_tg, ancestors, f));
         // Being killed with the unsafe task/closure pointers would leak them.
         do unkillable {
             // Agh. Get move-mode items into the closure. FIXME (#2829)
-            let (child_tg, ancestors, f) = option::swap_unwrap(child_data);
+            let (child_tg, ancestors, f) = child_data.take();
             // Create child task.
             let new_task = match opts.sched.mode {
                 DefaultScheduler => rt::new_task(),
@@ -571,10 +572,10 @@ pub fn spawn_raw(opts: TaskOpts, f: fn~()) {
                           ancestors: AncestorList, is_main: bool,
                           notify_chan: Option<Chan<TaskResult>>,
                           f: fn~()) -> fn~() {
-        let child_data = ~mut Some((child_arc, ancestors));
+        let child_data = Cell((child_arc, ancestors));
         return fn~() {
             // Agh. Get move-mode items into the closure. FIXME (#2829)
-            let mut (child_arc, ancestors) = option::swap_unwrap(child_data);
+            let mut (child_arc, ancestors) = child_data.take();
             // Child task runs this code.
 
             // Even if the below code fails to kick the child off, we must
diff --git a/src/librustc/middle/typeck/infer/region_inference.rs b/src/librustc/middle/typeck/infer/region_inference.rs
index cc5e860715d6d..ee59868665252 100644
--- a/src/librustc/middle/typeck/infer/region_inference.rs
+++ b/src/librustc/middle/typeck/infer/region_inference.rs
@@ -549,6 +549,7 @@ use syntax::codemap;
 use util::common::indenter;
 use util::ppaux::note_and_explain_region;
 
+use core::cell::{Cell, empty_cell};
 use core::cmp;
 use core::dvec::DVec;
 use core::to_bytes;
@@ -557,7 +558,6 @@ use core::vec;
 use result::Result;
 use result::{Ok, Err};
 use std::oldmap::HashMap;
-use std::cell::{Cell, empty_cell};
 use std::list::{List, Nil, Cons};
 use syntax::codemap::span;
 use syntax::codemap;
diff --git a/src/librustc/rustc.rc b/src/librustc/rustc.rc
index 01758a1845d7c..251e21578a523 100644
--- a/src/librustc/rustc.rc
+++ b/src/librustc/rustc.rc
@@ -314,8 +314,8 @@ fails without recording a fatal error then we've encountered a compiler
 bug and need to present an error.
 */
 pub fn monitor(+f: fn~(diagnostic::Emitter)) {
+    use core::cell::Cell;
     use core::comm::*;
-    use std::cell::Cell;
     let (p, ch) = stream();
     let ch = SharedChan(ch);
     let ch_capture = ch.clone();
diff --git a/src/librustdoc/astsrv.rs b/src/librustdoc/astsrv.rs
index fff2e189eb85c..1c45fdafa189c 100644
--- a/src/librustdoc/astsrv.rs
+++ b/src/librustdoc/astsrv.rs
@@ -21,8 +21,8 @@ use core::prelude::*;
 
 use parse;
 use util;
-use std::cell::Cell;
 
+use core::cell::Cell;
 use core::comm::{stream, Chan, SharedChan, Port};
 use core::vec;
 use core::ops::Drop;
diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index e904015e419f6..11a1b9f357657 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -10,6 +10,7 @@
 
 use core::prelude::*;
 
+use core::cell::Cell;
 use core::cmp;
 use core::os;
 use core::result;
@@ -18,7 +19,6 @@ use core::run::ProgramOutput;
 use core::vec;
 use core::result::Result;
 use std::getopts;
-use std::cell::Cell;
 
 /// The type of document to output
 pub enum OutputFormat {
diff --git a/src/librustdoc/markdown_pass.rs b/src/librustdoc/markdown_pass.rs
index ff9faabaec24b..f64f365496d83 100644
--- a/src/librustdoc/markdown_pass.rs
+++ b/src/librustdoc/markdown_pass.rs
@@ -34,11 +34,11 @@ use sort_pass;
 use trim_pass;
 use unindent_pass;
 
+use core::cell::Cell;
 use core::iter;
 use core::str;
 use core::vec;
 use std::par;
-use std::cell::Cell;
 use syntax;
 
 pub fn mk_pass(writer_factory: WriterFactory) -> Pass {
diff --git a/src/librustdoc/text_pass.rs b/src/librustdoc/text_pass.rs
index b9dbe523fdd33..83f35418b0b1f 100644
--- a/src/librustdoc/text_pass.rs
+++ b/src/librustdoc/text_pass.rs
@@ -20,8 +20,8 @@ use fold;
 use pass::Pass;
 use util::NominalOp;
 
+use core::cell::Cell;
 use std::par;
-use std::cell::Cell;
 
 pub fn mk_pass(name: ~str, op: @fn(&str) -> ~str) -> Pass {
     let op = Cell(op);
diff --git a/src/libstd/std.rc b/src/libstd/std.rc
index b985e579244dd..bdb455cc6549c 100644
--- a/src/libstd/std.rc
+++ b/src/libstd/std.rc
@@ -54,7 +54,6 @@ pub mod uv_global_loop;
 
 pub mod c_vec;
 pub mod timer;
-pub mod cell;
 pub mod io_util;
 
 // Concurrency