librustc: Disallow trait bounds in types, enumerations, and structure definitions. r=tjc

src/libcore/hashmap.rs

@@ -35,13 +35,13 @@ pub mod linear {
 
     const INITIAL_CAPACITY: uint = 32u; // 2^5
 
-    struct Bucket<K: Eq Hash, V> {
+    struct Bucket<K,V> {
         hash: uint,
         key: K,
         value: V,
     }
 
-    pub struct LinearMap<K: Eq Hash, V> {
+    pub struct LinearMap<K,V> {
         k0: u64,
         k1: u64,
         resize_at: uint,
@@ -408,7 +408,7 @@ pub mod linear {
         pure fn ne(&self, other: &LinearMap<K, V>) -> bool { !self.eq(other) }
     }
 
-    pub struct LinearSet<T: Hash IterBytes Eq> {
+    pub struct LinearSet<T> {
         priv map: LinearMap<T, ()>
     }
 

src/libcore/io.rs

@@ -1111,7 +1111,7 @@ pub mod fsync {
 
 
     // Artifacts that need to fsync on destruction
-    pub struct Res<t: Copy> {
+    pub struct Res<t> {
         arg: Arg<t>,
     }
 

src/libcore/oldcomm.rs

@@ -68,7 +68,7 @@ use vec;
  * transmitted. If a port value is copied, both copies refer to the same
  * port.  Ports may be associated with multiple `chan`s.
  */
-pub enum Port<T: Owned> {
+pub enum Port<T> {
     Port_(@PortPtr<T>)
 }
 
@@ -84,7 +84,7 @@ pub enum Port<T: Owned> {
  * data will be silently dropped.  Channels may be duplicated and
  * themselves transmitted over other channels.
  */
-pub enum Chan<T: Owned> {
+pub enum Chan<T> {
     Chan_(port_id)
 }
 
@@ -120,7 +120,7 @@ pub fn listen<T: Owned, U>(f: fn(Chan<T>) -> U) -> U {
     f(po.chan())
 }
 
-struct PortPtr<T:Owned> {
+struct PortPtr<T> {
   po: *rust_port,
   drop {
     unsafe {
@@ -238,7 +238,7 @@ fn peek_chan<T: Owned>(ch: Chan<T>) -> bool {
 }
 
 /// Receive on a raw port pointer
-fn recv_<T: Owned>(p: *rust_port) -> T {
+fn recv_<T>(p: *rust_port) -> T {
     unsafe {
         let yield = 0;
         let yieldp = ptr::addr_of(&yield);

src/libcore/pipes.rs

@@ -151,7 +151,7 @@ type Buffer<T: Owned> = {
 #[cfg(stage1)]
 #[cfg(stage2)]
 #[cfg(stage3)]
-pub struct Buffer<T: Owned> {
+pub struct Buffer<T> {
     header: BufferHeader,
     data: T,
 }
@@ -212,10 +212,18 @@ impl PacketHeader {
 }
 
 #[doc(hidden)]
+#[cfg(stage0)]
 pub struct Packet<T: Owned> {
     header: PacketHeader,
     mut payload: Option<T>,
 }
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub struct Packet<T> {
+    header: PacketHeader,
+    mut payload: Option<T>,
+}
 
 #[doc(hidden)]
 pub trait HasBuffer {
@@ -256,12 +264,11 @@ fn unibuffer<T: Owned>() -> ~Buffer<Packet<T>> {
     }
     move b
 }
-
 #[doc(hidden)]
 #[cfg(stage1)]
 #[cfg(stage2)]
 #[cfg(stage3)]
-fn unibuffer<T: Owned>() -> ~Buffer<Packet<T>> {
+fn unibuffer<T>() -> ~Buffer<Packet<T>> {
     let b = ~Buffer {
         header: BufferHeader(),
         data: Packet {
@@ -277,6 +284,7 @@ fn unibuffer<T: Owned>() -> ~Buffer<Packet<T>> {
 }
 
 #[doc(hidden)]
+#[cfg(stage0)]
 pub fn packet<T: Owned>() -> *Packet<T> {
     let b = unibuffer();
     let p = ptr::addr_of(&(b.data));
@@ -284,6 +292,16 @@ pub fn packet<T: Owned>() -> *Packet<T> {
     unsafe { forget(move b) }
     p
 }
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub fn packet<T>() -> *Packet<T> {
+    let b = unibuffer();
+    let p = ptr::addr_of(&(b.data));
+    // We'll take over memory management from here.
+    unsafe { forget(move b) }
+    p
+}
 
 #[doc(hidden)]
 pub fn entangle_buffer<T: Owned, Tstart: Owned>(
@@ -387,11 +405,19 @@ fn swap_state_rel(dst: &mut State, src: State) -> State {
 }
 
 #[doc(hidden)]
+#[cfg(stage0)]
 pub unsafe fn get_buffer<T: Owned>(p: *PacketHeader) -> ~Buffer<T> {
     transmute((*p).buf_header())
 }
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub unsafe fn get_buffer<T>(p: *PacketHeader) -> ~Buffer<T> {
+    transmute((*p).buf_header())
+}
 
 // This could probably be done with SharedMutableState to avoid move_it!().
+#[cfg(stage0)]
 struct BufferResource<T: Owned> {
     buffer: ~Buffer<T>,
 
@@ -413,7 +439,31 @@ struct BufferResource<T: Owned> {
         }
     }
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+struct BufferResource<T> {
+    buffer: ~Buffer<T>,
 
+    drop {
+        unsafe {
+            let b = move_it!(self.buffer);
+            //let p = ptr::addr_of(*b);
+            //error!("drop %?", p);
+            let old_count = atomic_sub_rel(&mut b.header.ref_count, 1);
+            //let old_count = atomic_xchng_rel(b.header.ref_count, 0);
+            if old_count == 1 {
+                // The new count is 0.
+
+                // go go gadget drop glue
+            }
+            else {
+                forget(move b)
+            }
+        }
+    }
+}
+
+#[cfg(stage0)]
 fn BufferResource<T: Owned>(b: ~Buffer<T>) -> BufferResource<T> {
     //let p = ptr::addr_of(*b);
     //error!("take %?", p);
@@ -424,8 +474,21 @@ fn BufferResource<T: Owned>(b: ~Buffer<T>) -> BufferResource<T> {
         buffer: move b
     }
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+fn BufferResource<T>(b: ~Buffer<T>) -> BufferResource<T> {
+    //let p = ptr::addr_of(*b);
+    //error!("take %?", p);
+    atomic_add_acq(&mut b.header.ref_count, 1);
+
+    BufferResource {
+        // tjc: ????
+        buffer: move b
+    }
+}
 
 #[doc(hidden)]
+#[cfg(stage0)]
 pub fn send<T: Owned, Tbuffer: Owned>(p: SendPacketBuffered<T, Tbuffer>,
                                     payload: T) -> bool {
     let header = p.header();
@@ -467,6 +530,49 @@ pub fn send<T: Owned, Tbuffer: Owned>(p: SendPacketBuffered<T, Tbuffer>,
         }
     }
 }
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub fn send<T,Tbuffer>(p: SendPacketBuffered<T,Tbuffer>, payload: T) -> bool {
+    let header = p.header();
+    let p_ = p.unwrap();
+    let p = unsafe { &*p_ };
+    assert ptr::addr_of(&(p.header)) == header;
+    assert p.payload.is_none();
+    p.payload = move Some(move payload);
+    let old_state = swap_state_rel(&mut p.header.state, Full);
+    match old_state {
+        Empty => {
+            // Yay, fastpath.
+
+            // The receiver will eventually clean this up.
+            //unsafe { forget(p); }
+            return true;
+        }
+        Full => fail ~"duplicate send",
+        Blocked => {
+            debug!("waking up task for %?", p_);
+            let old_task = swap_task(&mut p.header.blocked_task, ptr::null());
+            if !old_task.is_null() {
+                unsafe {
+                    rustrt::task_signal_event(
+                        old_task,
+                        ptr::addr_of(&(p.header)) as *libc::c_void);
+                    rustrt::rust_task_deref(old_task);
+                }
+            }
+
+            // The receiver will eventually clean this up.
+            //unsafe { forget(p); }
+            return true;
+        }
+        Terminated => {
+            // The receiver will never receive this. Rely on drop_glue
+            // to clean everything up.
+            return false;
+        }
+    }
+}
 
 /** Receives a message from a pipe.
 
@@ -812,13 +918,24 @@ pub fn select<T: Owned, Tb: Owned>(endpoints: ~[RecvPacketBuffered<T, Tb>])
 message.
 
 */
+#[cfg(stage0)]
 pub type SendPacket<T: Owned> = SendPacketBuffered<T, Packet<T>>;
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub type SendPacket<T> = SendPacketBuffered<T, Packet<T>>;
 
 #[doc(hidden)]
+#[cfg(stage0)]
 pub fn SendPacket<T: Owned>(p: *Packet<T>) -> SendPacket<T> {
     SendPacketBuffered(p)
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub fn SendPacket<T>(p: *Packet<T>) -> SendPacket<T> {
+    SendPacketBuffered(p)
+}
 
+#[cfg(stage0)]
 pub struct SendPacketBuffered<T: Owned, Tbuffer: Owned> {
     mut p: Option<*Packet<T>>,
     mut buffer: Option<BufferResource<Tbuffer>>,
@@ -837,7 +954,31 @@ pub struct SendPacketBuffered<T: Owned, Tbuffer: Owned> {
         //                } else { "some" }); }
     }
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub struct SendPacketBuffered<T, Tbuffer> {
+    mut p: Option<*Packet<T>>,
+    mut buffer: Option<BufferResource<Tbuffer>>,
+}
 
+impl<T:Owned,Tbuffer:Owned> SendPacketBuffered<T,Tbuffer> : ::ops::Drop {
+    fn finalize(&self) {
+        //if self.p != none {
+        //    debug!("drop send %?", option::get(self.p));
+        //}
+        if self.p != None {
+            let mut p = None;
+            p <-> self.p;
+            sender_terminate(option::unwrap(move p))
+        }
+        //unsafe { error!("send_drop: %?",
+        //                if self.buffer == none {
+        //                    "none"
+        //                } else { "some" }); }
+    }
+}
+
+#[cfg(stage0)]
 pub fn SendPacketBuffered<T: Owned, Tbuffer: Owned>(p: *Packet<T>)
     -> SendPacketBuffered<T, Tbuffer> {
         //debug!("take send %?", p);
@@ -849,8 +990,50 @@ pub fn SendPacketBuffered<T: Owned, Tbuffer: Owned>(p: *Packet<T>)
         }
     }
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub fn SendPacketBuffered<T,Tbuffer>(p: *Packet<T>)
+    -> SendPacketBuffered<T, Tbuffer> {
+        //debug!("take send %?", p);
+    SendPacketBuffered {
+        p: Some(p),
+        buffer: unsafe {
+            Some(BufferResource(
+                get_buffer(ptr::addr_of(&((*p).header)))))
+        }
+    }
+}
 
-impl<T: Owned, Tbuffer: Owned> SendPacketBuffered<T, Tbuffer> {
+#[cfg(stage0)]
+impl<T:Owned,Tbuffer:Owned> SendPacketBuffered<T,Tbuffer> {
+    fn unwrap() -> *Packet<T> {
+        let mut p = None;
+        p <-> self.p;
+        option::unwrap(move p)
+    }
+
+    pure fn header() -> *PacketHeader {
+        match self.p {
+          Some(packet) => unsafe {
+            let packet = &*packet;
+            let header = ptr::addr_of(&(packet.header));
+            //forget(packet);
+            header
+          },
+          None => fail ~"packet already consumed"
+        }
+    }
+
+    fn reuse_buffer() -> BufferResource<Tbuffer> {
+        //error!("send reuse_buffer");
+        let mut tmp = None;
+        tmp <-> self.buffer;
+        option::unwrap(move tmp)
+    }
+}
+#[cfg(stage1)]
+#[cfg(stage2)]
+impl<T,Tbuffer> SendPacketBuffered<T,Tbuffer> {
     fn unwrap() -> *Packet<T> {
         let mut p = None;
         p <-> self.p;
@@ -879,13 +1062,25 @@ impl<T: Owned, Tbuffer: Owned> SendPacketBuffered<T, Tbuffer> {
 
 /// Represents the receive end of a pipe. It can receive exactly one
 /// message.
+#[cfg(stage0)]
 pub type RecvPacket<T: Owned> = RecvPacketBuffered<T, Packet<T>>;
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub type RecvPacket<T> = RecvPacketBuffered<T, Packet<T>>;
 
 #[doc(hidden)]
+#[cfg(stage0)]
 pub fn RecvPacket<T: Owned>(p: *Packet<T>) -> RecvPacket<T> {
     RecvPacketBuffered(p)
 }
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub fn RecvPacket<T>(p: *Packet<T>) -> RecvPacket<T> {
+    RecvPacketBuffered(p)
+}
 
+#[cfg(stage0)]
 pub struct RecvPacketBuffered<T: Owned, Tbuffer: Owned> {
     mut p: Option<*Packet<T>>,
     mut buffer: Option<BufferResource<Tbuffer>>,
@@ -904,6 +1099,29 @@ pub struct RecvPacketBuffered<T: Owned, Tbuffer: Owned> {
         //                } else { "some" }); }
     }
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub struct RecvPacketBuffered<T, Tbuffer> {
+    mut p: Option<*Packet<T>>,
+    mut buffer: Option<BufferResource<Tbuffer>>,
+}
+
+impl<T:Owned, Tbuffer:Owned> RecvPacketBuffered<T,Tbuffer> : ::ops::Drop {
+    fn finalize(&self) {
+        //if self.p != none {
+        //    debug!("drop recv %?", option::get(self.p));
+        //}
+        if self.p != None {
+            let mut p = None;
+            p <-> self.p;
+            receiver_terminate(option::unwrap(move p))
+        }
+        //unsafe { error!("recv_drop: %?",
+        //                if self.buffer == none {
+        //                    "none"
+        //                } else { "some" }); }
+    }
+}
 
 impl<T: Owned, Tbuffer: Owned> RecvPacketBuffered<T, Tbuffer> {
     fn unwrap() -> *Packet<T> {
@@ -934,6 +1152,7 @@ impl<T: Owned, Tbuffer: Owned> RecvPacketBuffered<T, Tbuffer> : Selectable {
     }
 }
 
+#[cfg(stage0)]
 pub fn RecvPacketBuffered<T: Owned, Tbuffer: Owned>(p: *Packet<T>)
     -> RecvPacketBuffered<T, Tbuffer> {
     //debug!("take recv %?", p);
@@ -945,12 +1164,33 @@ pub fn RecvPacketBuffered<T: Owned, Tbuffer: Owned>(p: *Packet<T>)
         }
     }
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub fn RecvPacketBuffered<T,Tbuffer>(p: *Packet<T>)
+    -> RecvPacketBuffered<T,Tbuffer> {
+    //debug!("take recv %?", p);
+    RecvPacketBuffered {
+        p: Some(p),
+        buffer: unsafe {
+            Some(BufferResource(
+                get_buffer(ptr::addr_of(&((*p).header)))))
+        }
+    }
+}
 
 #[doc(hidden)]
+#[cfg(stage0)]
 pub fn entangle<T: Owned>() -> (SendPacket<T>, RecvPacket<T>) {
     let p = packet();
     (SendPacket(p), RecvPacket(p))
 }
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub fn entangle<T>() -> (SendPacket<T>, RecvPacket<T>) {
+    let p = packet();
+    (SendPacket(p), RecvPacket(p))
+}
 
 /** Spawn a task to provide a service.
 
@@ -1042,24 +1282,50 @@ pub trait Peekable<T> {
 }
 
 #[doc(hidden)]
+#[cfg(stage0)]
 struct Chan_<T:Owned> {
-    mut endp: Option<streamp::client::Open<T>>,
+    mut endp: Option<streamp::client::Open<T>>
+}
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+struct Chan_<T> {
+    mut endp: Option<streamp::client::Open<T>>
 }
 
 /// An endpoint that can send many messages.
+#[cfg(stage0)]
 pub enum Chan<T:Owned> {
     Chan_(Chan_<T>)
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub enum Chan<T> {
+    Chan_(Chan_<T>)
+}
 
 #[doc(hidden)]
+#[cfg(stage0)]
 struct Port_<T:Owned> {
     mut endp: Option<streamp::server::Open<T>>,
 }
+#[doc(hidden)]
+#[cfg(stage1)]
+#[cfg(stage2)]
+struct Port_<T> {
+    mut endp: Option<streamp::server::Open<T>>,
+}
 
 /// An endpoint that can receive many messages.
+#[cfg(stage0)]
 pub enum Port<T:Owned> {
     Port_(Port_<T>)
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub enum Port<T> {
+    Port_(Port_<T>)
+}
 
 /** Creates a `(chan, port)` pair.
 
@@ -1145,9 +1411,15 @@ impl<T: Owned> Port<T>: Selectable {
 }
 
 /// Treat many ports as one.
+#[cfg(stage0)]
 pub struct PortSet<T: Owned> {
     mut ports: ~[pipes::Port<T>],
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub struct PortSet<T> {
+    mut ports: ~[pipes::Port<T>],
+}
 
 pub fn PortSet<T: Owned>() -> PortSet<T>{
     PortSet {
@@ -1210,7 +1482,11 @@ impl<T: Owned> PortSet<T> : Peekable<T> {
 }
 
 /// A channel that can be shared between many senders.
+#[cfg(stage0)]
 pub type SharedChan<T: Owned> = private::Exclusive<Chan<T>>;
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub type SharedChan<T> = private::Exclusive<Chan<T>>;
 
 impl<T: Owned> SharedChan<T>: GenericChan<T> {
     fn send(x: T) {
@@ -1278,9 +1554,17 @@ proto! oneshot (
 )
 
 /// The send end of a oneshot pipe.
+#[cfg(stage0)]
 pub type ChanOne<T: Owned> = oneshot::client::Oneshot<T>;
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub type ChanOne<T> = oneshot::client::Oneshot<T>;
 /// The receive end of a oneshot pipe.
+#[cfg(stage0)]
 pub type PortOne<T: Owned> = oneshot::server::Oneshot<T>;
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub type PortOne<T> = oneshot::server::Oneshot<T>;
 
 /// Initialiase a (send-endpoint, recv-endpoint) oneshot pipe pair.
 pub fn oneshot<T: Owned>() -> (PortOne<T>, ChanOne<T>) {

src/libcore/private.rs

@@ -238,7 +238,7 @@ pub unsafe fn unwrap_shared_mutable_state<T: Owned>(rc: SharedMutableState<T>)
  * Data races between tasks can result in crashes and, with sufficient
  * cleverness, arbitrary type coercion.
  */
-pub type SharedMutableState<T: Owned> = ArcDestruct<T>;
+pub type SharedMutableState<T> = ArcDestruct<T>;
 
 pub unsafe fn shared_mutable_state<T: Owned>(data: T) ->
         SharedMutableState<T> {
@@ -341,11 +341,11 @@ impl LittleLock {
     }
 }
 
-struct ExData<T: Owned> { lock: LittleLock, mut failed: bool, mut data: T, }
+struct ExData<T> { lock: LittleLock, mut failed: bool, mut data: T, }
 /**
  * An arc over mutable data that is protected by a lock. For library use only.
  */
-pub struct Exclusive<T: Owned> { x: SharedMutableState<ExData<T>> }
+pub struct Exclusive<T> { x: SharedMutableState<ExData<T>> }
 
 pub fn exclusive<T:Owned >(user_data: T) -> Exclusive<T> {
     let data = ExData {

src/libcore/private/global.rs

@@ -41,7 +41,7 @@ use sys::Closure;
 use task::spawn;
 use uint;
 
-pub type GlobalDataKey<T: Owned> = &fn(v: T);
+pub type GlobalDataKey<T> = &fn(v: T);
 
 pub unsafe fn global_data_clone_create<T: Owned Clone>(
     key: GlobalDataKey<T>, create: &fn() -> ~T) -> T {

src/libcore/reflect.rs

@@ -41,7 +41,7 @@ pub fn align(size: uint, align: uint) -> uint {
 }
 
 /// Adaptor to wrap around visitors implementing MovePtr.
-pub struct MovePtrAdaptor<V: TyVisitor MovePtr> {
+pub struct MovePtrAdaptor<V> {
     inner: V
 }
 pub fn MovePtrAdaptor<V: TyVisitor MovePtr>(v: V) -> MovePtrAdaptor<V> {

src/libcore/task/local_data.rs

@@ -45,7 +45,7 @@ use task;
  *
  * These two cases aside, the interface is safe.
  */
-pub type LocalDataKey<T: Durable> = &fn(v: @T);
+pub type LocalDataKey<T> = &fn(v: @T);
 
 /**
  * Remove a task-local data value from the table, returning the

src/libcore/task/spawn.rs

@@ -77,7 +77,7 @@ use cast;
 use container::Map;
 use oldcomm;
 use option;
-use pipes::{Chan, GenericChan, GenericPort, Port};
+use pipes::{Chan, GenericChan, GenericPort, Port, stream};
 use pipes;
 use prelude::*;
 use private;

src/librustc/middle/ty.rs

@@ -569,7 +569,7 @@ struct FnSig {
  * by the meta information because, in some cases, the
  * meta information is inferred. */
 #[deriving_eq]
-struct FnTyBase<M: cmp::Eq> {
+struct FnTyBase<M> {
     meta: M,        // Either FnMeta or FnVid
     sig: FnSig      // Types of arguments/return type
 }

src/librustc/middle/typeck/collect.rs

@@ -598,6 +598,20 @@ fn convert_methods(ccx: @crate_ctxt,
     }
 }
 
+fn ensure_no_ty_param_bounds(ccx: @crate_ctxt,
+                             span: span,
+                             ty_params: &[ast::ty_param],
+                             thing: &static/str) {
+    for ty_params.each |ty_param| {
+        if ty_param.bounds.len() > 0 {
+            ccx.tcx.sess.span_err(
+                span,
+                fmt!("trait bounds are not allowed in %s definitions",
+                     thing));
+        }
+    }
+}
+
 fn convert(ccx: @crate_ctxt, it: @ast::item) {
     let tcx = ccx.tcx;
     let rp = tcx.region_paramd_items.find(it.id);
@@ -607,6 +621,7 @@ fn convert(ccx: @crate_ctxt, it: @ast::item) {
       // These don't define types.
       ast::item_foreign_mod(_) | ast::item_mod(_) => {}
       ast::item_enum(ref enum_definition, ref ty_params) => {
+        ensure_no_ty_param_bounds(ccx, it.span, *ty_params, "enumeration");
         let tpt = ty_of_item(ccx, it);
         write_ty_to_tcx(tcx, it.id, tpt.ty);
         get_enum_variant_types(ccx,
@@ -644,6 +659,8 @@ fn convert(ccx: @crate_ctxt, it: @ast::item) {
         let _ = convert_methods(ccx, provided_methods, rp, bounds);
       }
       ast::item_struct(struct_def, tps) => {
+        ensure_no_ty_param_bounds(ccx, it.span, tps, "structure");
+
         // Write the class type
         let tpt = ty_of_item(ccx, it);
         write_ty_to_tcx(tcx, it.id, tpt.ty);
@@ -651,6 +668,11 @@ fn convert(ccx: @crate_ctxt, it: @ast::item) {
 
         convert_struct(ccx, rp, struct_def, tps, tpt, it.id);
       }
+      ast::item_ty(_, ref ty_params) => {
+        ensure_no_ty_param_bounds(ccx, it.span, *ty_params, "type");
+        let tpt = ty_of_item(ccx, it);
+        write_ty_to_tcx(tcx, it.id, tpt.ty);
+      }
       _ => {
         // This call populates the type cache with the converted type
         // of the item in passing. All we have to do here is to write

src/librustc/middle/typeck/infer/unify.rs

@@ -31,7 +31,7 @@ struct ValsAndBindings<V, T> {
     mut bindings: ~[(V, VarValue<V, T>)],
 }
 
-struct Node<V:Copy, T:Copy> {
+struct Node<V, T> {
     root: V,
     possible_types: T,
     rank: uint,

src/libstd/arc.rs

@@ -79,7 +79,7 @@ impl &Condvar {
  ****************************************************************************/
 
 /// An atomically reference counted wrapper for shared immutable state.
-struct ARC<T: Const Owned> { x: SharedMutableState<T> }
+struct ARC<T> { x: SharedMutableState<T> }
 
 /// Create an atomically reference counted wrapper.
 pub fn ARC<T: Const Owned>(data: T) -> ARC<T> {
@@ -130,9 +130,9 @@ impl<T: Const Owned> ARC<T>: Clone {
  ****************************************************************************/
 
 #[doc(hidden)]
-struct MutexARCInner<T: Owned> { lock: Mutex, failed: bool, data: T }
+struct MutexARCInner<T> { lock: Mutex, failed: bool, data: T }
 /// An ARC with mutable data protected by a blocking mutex.
-struct MutexARC<T: Owned> { x: SharedMutableState<MutexARCInner<T>> }
+struct MutexARC<T> { x: SharedMutableState<MutexARCInner<T>> }
 
 /// Create a mutex-protected ARC with the supplied data.
 pub fn MutexARC<T: Owned>(user_data: T) -> MutexARC<T> {
@@ -267,14 +267,14 @@ fn PoisonOnFail(failed: &r/mut bool) -> PoisonOnFail {
  ****************************************************************************/
 
 #[doc(hidden)]
-struct RWARCInner<T: Const Owned> { lock: RWlock, failed: bool, data: T }
+struct RWARCInner<T> { lock: RWlock, failed: bool, data: T }
 /**
  * A dual-mode ARC protected by a reader-writer lock. The data can be accessed
  * mutably or immutably, and immutably-accessing tasks may run concurrently.
  *
  * Unlike mutex_arcs, rw_arcs are safe, because they cannot be nested.
  */
-struct RWARC<T: Const Owned> {
+struct RWARC<T> {
     x: SharedMutableState<RWARCInner<T>>,
     mut cant_nest: ()
 }
@@ -426,10 +426,10 @@ fn borrow_rwlock<T: Const Owned>(state: &r/mut RWARCInner<T>) -> &r/RWlock {
 // FIXME (#3154) ice with struct/&<T> prevents these from being structs.
 
 /// The "write permission" token used for RWARC.write_downgrade().
-pub enum RWWriteMode<T: Const Owned> =
+pub enum RWWriteMode<T> =
     (&mut T, sync::RWlockWriteMode, PoisonOnFail);
 /// The "read permission" token used for RWARC.write_downgrade().
-pub enum RWReadMode<T:Const Owned> = (&T, sync::RWlockReadMode);
+pub enum RWReadMode<T> = (&T, sync::RWlockReadMode);
 
 impl<T: Const Owned> &RWWriteMode<T> {
     /// Access the pre-downgrade RWARC in write mode.

src/libstd/comm.rs

@@ -23,7 +23,14 @@ use core::pipes;
 use core::prelude::*;
 
 /// An extension of `pipes::stream` that allows both sending and receiving.
-pub struct DuplexStream<T: Owned, U: Owned> {
+#[cfg(stage0)]
+pub struct DuplexStream<T:Owned, U:Owned> {
+    priv chan: Chan<T>,
+    priv port: Port<U>,
+}
+#[cfg(stage1)]
+#[cfg(stage2)]
+pub struct DuplexStream<T, U> {
     priv chan: Chan<T>,
     priv port: Port<U>,
 }

src/libstd/flatpipes.rs

@@ -63,7 +63,7 @@ and an `Unflattener` that converts the bytes to a value.
 
 Create using the constructors in the `serial` and `pod` modules.
 */
-pub struct FlatPort<T, U: Unflattener<T>, P: BytePort> {
+pub struct FlatPort<T, U, P> {
     unflattener: U,
     byte_port: P
 }
@@ -74,7 +74,7 @@ byte vectors, and a `ByteChan` that transmits the bytes.
 
 Create using the constructors in the `serial` and `pod` modules.
 */
-pub struct FlatChan<T, F: Flattener<T>, C: ByteChan> {
+pub struct FlatChan<T, F, C> {
     flattener: F,
     byte_chan: C
 }
@@ -181,14 +181,12 @@ pub mod pod {
     use core::pipes;
     use core::prelude::*;
 
-    pub type ReaderPort<T: Copy Owned, R> =
+    pub type ReaderPort<T, R> =
         FlatPort<T, PodUnflattener<T>, ReaderBytePort<R>>;
-    pub type WriterChan<T: Copy Owned, W> =
+    pub type WriterChan<T, W> =
         FlatChan<T, PodFlattener<T>, WriterByteChan<W>>;
-    pub type PipePort<T: Copy Owned> =
+    pub type PipePort<T> = FlatPort<T, PodUnflattener<T>, PipeBytePort>;
-        FlatPort<T, PodUnflattener<T>, PipeBytePort>;
+    pub type PipeChan<T> = FlatChan<T, PodFlattener<T>, PipeByteChan>;
-    pub type PipeChan<T: Copy Owned> =
-        FlatChan<T, PodFlattener<T>, PipeByteChan>;
 
     /// Create a `FlatPort` from a `Reader`
     pub fn reader_port<T: Copy Owned, R: Reader>(
@@ -352,11 +350,11 @@ pub mod flatteners {
 
 
     // FIXME #4074: Copy + Owned != POD
-    pub struct PodUnflattener<T: Copy Owned> {
+    pub struct PodUnflattener<T> {
         bogus: ()
     }
 
-    pub struct PodFlattener<T: Copy Owned> {
+    pub struct PodFlattener<T> {
         bogus: ()
     }
 
@@ -398,14 +396,13 @@ pub mod flatteners {
 
     pub type DeserializeBuffer<T> = ~fn(buf: &[u8]) -> T;
 
-    pub struct DeserializingUnflattener<D: Decoder,
+    pub struct DeserializingUnflattener<D, T> {
-                                        T: Decodable<D>> {
         deserialize_buffer: DeserializeBuffer<T>
     }
 
     pub type SerializeValue<T> = ~fn(val: &T) -> ~[u8];
 
-    pub struct SerializingFlattener<S: Encoder, T: Encodable<S>> {
+    pub struct SerializingFlattener<S, T> {
         serialize_value: SerializeValue<T>
     }
 
@@ -518,11 +515,11 @@ pub mod bytepipes {
     use core::pipes;
     use core::prelude::*;
 
-    pub struct ReaderBytePort<R: Reader> {
+    pub struct ReaderBytePort<R> {
         reader: R
     }
 
-    pub struct WriterByteChan<W: Writer> {
+    pub struct WriterByteChan<W> {
         writer: W
     }
 
@@ -767,9 +764,9 @@ mod test {
         test_some_tcp_stream(reader_port, writer_chan, 9667);
     }
 
-    type ReaderPortFactory<U: Unflattener<int>> =
+    type ReaderPortFactory<U> =
         ~fn(TcpSocketBuf) -> FlatPort<int, U, ReaderBytePort<TcpSocketBuf>>;
-    type WriterChanFactory<F: Flattener<int>> =
+    type WriterChanFactory<F> =
         ~fn(TcpSocketBuf) -> FlatChan<int, F, WriterByteChan<TcpSocketBuf>>;
 
     fn test_some_tcp_stream<U: Unflattener<int>, F: Flattener<int>>(
@@ -893,7 +890,7 @@ mod test {
         use core::sys;
         use core::task;
 
-        type PortLoader<P: BytePort> =
+        type PortLoader<P> =
             ~fn(~[u8]) -> FlatPort<int, PodUnflattener<int>, P>;
 
         fn reader_port_loader(bytes: ~[u8]

src/libstd/map.rs

@@ -24,9 +24,9 @@ use core::uint;
 use core::vec;
 
 /// A convenience type to treat a hashmap as a set
-pub type Set<K:Eq IterBytes Hash> = HashMap<K, ()>;
+pub type Set<K> = HashMap<K, ()>;
 
-pub type HashMap<K:Eq IterBytes Hash, V> = chained::T<K, V>;
+pub type HashMap<K, V> = chained::T<K, V>;
 
 pub trait StdMap<K:Eq IterBytes Hash Copy, V: Copy> {
     /// Return the number of elements in the map
@@ -142,12 +142,12 @@ pub mod chained {
         mut next: Option<@Entry<K, V>>
     }
 
-    struct HashMap_<K:Eq IterBytes Hash, V> {
+    struct HashMap_<K, V> {
         mut count: uint,
         mut chains: ~[mut Option<@Entry<K,V>>]
     }
 
-    pub type T<K:Eq IterBytes Hash, V> = @HashMap_<K, V>;
+    pub type T<K, V> = @HashMap_<K, V>;
 
     enum SearchResult<K, V> {
         NotFound,

src/libstd/priority_queue.rs

@@ -22,7 +22,7 @@ extern "C" mod rusti {
     fn init<T>() -> T;
 }
 
-pub struct PriorityQueue <T: Ord>{
+pub struct PriorityQueue<T> {
     priv data: ~[T],
 }
 

src/libstd/sync.rs

@@ -83,7 +83,7 @@ struct SemInner<Q> {
     blocked:   Q
 }
 #[doc(hidden)]
-enum Sem<Q: Owned> = Exclusive<SemInner<Q>>;
+enum Sem<Q> = Exclusive<SemInner<Q>>;
 
 #[doc(hidden)]
 fn new_sem<Q: Owned>(count: int, q: Q) -> Sem<Q> {
@@ -167,7 +167,7 @@ impl &Sem<~[mut Waitqueue]> {
 #[doc(hidden)]
 type SemRelease = SemReleaseGeneric<()>;
 type SemAndSignalRelease = SemReleaseGeneric<~[mut Waitqueue]>;
-struct SemReleaseGeneric<Q: Owned> { sem: &Sem<Q> }
+struct SemReleaseGeneric<Q> { sem: &Sem<Q> }
 
 impl<Q: Owned> SemReleaseGeneric<Q> : Drop {
     fn finalize(&self) {

src/libstd/treemap.rs

@@ -35,7 +35,7 @@ use core::prelude::*;
 //   * symmetric difference: ^
 // These would be convenient since the methods work like `each`
 
-pub struct TreeMap<K: Ord, V> {
+pub struct TreeMap<K, V> {
     priv root: Option<~TreeNode<K, V>>,
     priv length: uint
 }
@@ -202,7 +202,7 @@ impl <K: Ord, V> TreeMap<K, V> {
 }
 
 /// Lazy forward iterator over a map
-pub struct TreeMapIterator<K: Ord, V> {
+pub struct TreeMapIterator<K, V> {
     priv stack: ~[&~TreeNode<K, V>],
     priv node: &Option<~TreeNode<K, V>>,
     priv current: Option<&~TreeNode<K, V>>
@@ -240,7 +240,7 @@ impl <K: Ord, V> TreeMapIterator<K, V> {
     }
 }
 
-pub struct TreeSet<T: Ord> {
+pub struct TreeSet<T> {
     priv map: TreeMap<T, ()>
 }
 
@@ -518,7 +518,7 @@ impl <T: Ord> TreeSet<T> {
 }
 
 /// Lazy forward iterator over a set
-pub struct TreeSetIterator<T: Ord> {
+pub struct TreeSetIterator<T> {
     priv iter: TreeMapIterator<T, ()>
 }
 
@@ -540,7 +540,7 @@ impl <T: Ord> TreeSetIterator<T> {
 
 // Nodes keep track of their level in the tree, starting at 1 in the
 // leaves and with a red child sharing the level of the parent.
-struct TreeNode<K: Ord, V> {
+struct TreeNode<K, V> {
     key: K,
     value: V,
     left: Option<~TreeNode<K, V>>,

src/libstd/workcache.rs

@@ -235,10 +235,17 @@ struct Exec {
     discovered_outputs: WorkMap
 }
 
+#[cfg(stage0)]
 struct Work<T:Owned> {
     prep: @Mut<Prep>,
     res: Option<Either<T,PortOne<(Exec,T)>>>
 }
+#[cfg(stage1)]
+#[cfg(stage2)]
+struct Work<T> {
+    prep: @Mut<Prep>,
+    res: Option<Either<T,PortOne<(Exec,T)>>>
+}
 
 fn json_encode<T:Encodable<json::Encoder>>(t: &T) -> ~str {
     do io::with_str_writer |wr| {

src/libsyntax/ext/pipes/ast_builder.rs

@@ -110,6 +110,7 @@ pub trait ext_ctxt_ast_builder {
     fn ty_option(ty: @ast::Ty) -> @ast::Ty;
     fn ty_infer() -> @ast::Ty;
     fn ty_nil_ast_builder() -> @ast::Ty;
+    fn strip_bounds(bounds: &[ast::ty_param]) -> ~[ast::ty_param];
 }
 
 impl ext_ctxt: ext_ctxt_ast_builder {
@@ -370,6 +371,12 @@ impl ext_ctxt: ext_ctxt_ast_builder {
         }
     }
 
+    fn strip_bounds(bounds: &[ast::ty_param]) -> ~[ast::ty_param] {
+        do bounds.map |ty_param| {
+            ast::ty_param { bounds: @~[], ..copy *ty_param }
+        }
+    }
+
     fn item_ty_poly(name: ident,
                     span: span,
                     ty: @ast::Ty,

src/libsyntax/ext/pipes/pipec.rs

@@ -248,7 +248,7 @@ impl state: to_type_decls {
                 ast::enum_def(enum_def_ {
                     variants: items_msg,
                     common: None }),
-                self.ty_params
+                cx.strip_bounds(self.ty_params)
             )
         ]
     }
@@ -281,7 +281,7 @@ impl state: to_type_decls {
                                    self.data_name()],
                                  dummy_sp())
                             .add_tys(cx.ty_vars_global(self.ty_params))))),
-                    self.ty_params));
+                    cx.strip_bounds(self.ty_params)));
         }
         else {
             items.push(
@@ -299,7 +299,7 @@ impl state: to_type_decls {
                                         dummy_sp())
                             .add_tys(cx.ty_vars_global(self.ty_params))),
                                    self.proto.buffer_ty_path(cx)])),
-                    self.ty_params));
+                    cx.strip_bounds(self.ty_params)));
         };
         items
     }
@@ -417,7 +417,7 @@ impl protocol: gen_init {
             cx.ident_of(~"__Buffer"),
             dummy_sp(),
             cx.ty_rec(fields),
-            params)
+            cx.strip_bounds(params))
     }
 
     fn compile(cx: ext_ctxt) -> @ast::item {

src/libsyntax/parse/obsolete.rs

@@ -33,6 +33,7 @@ use core::str;
 use core::to_bytes;
 
 /// The specific types of unsupported syntax
+#[deriving_eq]
 pub enum ObsoleteSyntax {
     ObsoleteLowerCaseKindBounds,
     ObsoleteLet,
@@ -45,16 +46,8 @@ pub enum ObsoleteSyntax {
     ObsoleteModeInFnType,
     ObsoleteMoveInit,
     ObsoleteBinaryMove,
-    ObsoleteUnsafeBlock
+    ObsoleteUnsafeBlock,
-}
+    ObsoleteUnenforcedBound
-
-impl ObsoleteSyntax : cmp::Eq {
-    pure fn eq(&self, other: &ObsoleteSyntax) -> bool {
-        (*self) as uint == (*other) as uint
-    }
-    pure fn ne(&self, other: &ObsoleteSyntax) -> bool {
-        !(*self).eq(other)
-    }
 }
 
 impl ObsoleteSyntax: to_bytes::IterBytes {
@@ -123,6 +116,11 @@ impl Parser {
             ObsoleteUnsafeBlock => (
                 "non-standalone unsafe block",
                 "use an inner `unsafe { ... }` block instead"
+            ),
+            ObsoleteUnenforcedBound => (
+                "unenforced type parameter bound",
+                "use trait bounds on the functions that take the type as \
+                 arguments, not on the types themselves"
             )
         };
 

src/libsyntax/util/interner.rs

@@ -18,7 +18,7 @@ use core::dvec::DVec;
 use std::map::HashMap;
 use std::map;
 
-type hash_interner<T: Const> =
+type hash_interner<T> =
     {map: HashMap<T, uint>,
      vect: DVec<T>};
 

src/test/auxiliary/issue-2526.rs

@@ -17,7 +17,7 @@ extern mod std;
 
 export context;
 
-struct arc_destruct<T:Const> {
+struct arc_destruct<T> {
   _data: int,
 }
 

src/test/auxiliary/test_comm.rs

@@ -24,7 +24,7 @@ use core::libc::size_t;
  * transmitted. If a port value is copied, both copies refer to the same
  * port.  Ports may be associated with multiple `chan`s.
  */
-pub enum port<T: Owned> {
+pub enum port<T> {
     port_t(@port_ptr<T>)
 }
 
@@ -35,7 +35,7 @@ pub fn port<T: Owned>() -> port<T> {
     }
 }
 
-struct port_ptr<T:Owned> {
+struct port_ptr<T> {
    po: *rust_port,
 }
 

src/test/bench/task-perf-word-count-generic.rs

@@ -122,15 +122,15 @@ mod map_reduce {
     use std::map::HashMap;
     use std::map;
 
-    pub type putter<K: Owned, V: Owned> = fn(&K, V);
+    pub type putter<K, V> = fn(&K, V);
 
-    pub type mapper<K1: Owned, K2: Owned, V: Owned> = fn~(K1, putter<K2, V>);
+    pub type mapper<K1, K2, V> = fn~(K1, putter<K2, V>);
 
-    pub type getter<V: Owned> = fn() -> Option<V>;
+    pub type getter<V> = fn() -> Option<V>;
 
-    pub type reducer<K: Copy Owned, V: Copy Owned> = fn~(&K, getter<V>);
+    pub type reducer<K, V> = fn~(&K, getter<V>);
 
-    enum ctrl_proto<K: Copy Owned, V: Copy Owned> {
+    enum ctrl_proto<K, V> {
         find_reducer(K, Chan<Chan<::map_reduce::reduce_proto<V>>>),
         mapper_done
     }
@@ -148,7 +148,7 @@ mod map_reduce {
         }
     )
 
-    pub enum reduce_proto<V: Copy Owned> {
+    pub enum reduce_proto<V> {
         emit_val(V),
         done,
         addref,

src/test/compile-fail/issue-2718-a.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-pub struct send_packet<T: Copy> {
+pub struct send_packet<T> {
   p: T
 }
 

src/test/run-fail/bug-811.rs

@@ -14,7 +14,7 @@ fn test00_start(ch: chan_t<int>, message: int) { send(ch, message); }
 type task_id = int;
 type port_id = int;
 
-enum chan_t<T: Owned> = {task: task_id, port: port_id};
+enum chan_t<T> = {task: task_id, port: port_id};
 
 fn send<T: Owned>(ch: chan_t<T>, data: T) { fail; }
 

src/test/run-fail/issue-2444.rs

@@ -13,7 +13,7 @@
 extern mod std;
 use std::arc;
 
-enum e<T: Const Owned> { e(arc::ARC<T>) }
+enum e<T> { e(arc::ARC<T>) }
 
 fn foo() -> e<int> {fail;}
 

src/test/run-pass/auto-encode.rs

@@ -135,11 +135,6 @@ struct Spanned<T> {
     node: T,
 }
 
-enum AnEnum {
-    AVariant,
-    AnotherVariant
-}
-
 #[auto_encode]
 #[auto_decode]
 struct SomeStruct { v: ~[uint] }

src/test/run-pass/box-unbox.rs

@@ -10,7 +10,7 @@
 
 
 
-struct Box<T: Copy> {c: @T}
+struct Box<T> {c: @T}
 
 fn unbox<T: Copy>(b: Box<T>) -> T { return *b.c; }
 

src/test/run-pass/class-impl-very-parameterized-trait.rs

@@ -27,7 +27,7 @@ impl cat_type : cmp::Eq {
 // for any int value that's less than the meows field
 
 // ok: T should be in scope when resolving the trait ref for map
-struct cat<T: Copy> {
+struct cat<T> {
   // Yes, you can have negative meows
   priv mut meows : int,
 

src/test/run-pass/generic-exterior-box.rs

@@ -10,7 +10,7 @@
 
 
 
-struct Recbox<T: Copy> {x: @T}
+struct Recbox<T> {x: @T}
 
 fn reclift<T: Copy>(t: T) -> Recbox<T> { return Recbox {x: @t}; }
 

src/test/run-pass/generic-exterior-unique.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-struct Recbox<T: Copy> {x: ~T}
+struct Recbox<T> {x: ~T}
 
 fn reclift<T: Copy>(t: T) -> Recbox<T> { return Recbox {x: ~t}; }
 

src/test/run-pass/issue-2288.rs

@@ -11,7 +11,7 @@
 trait clam<A: Copy> {
   fn chowder(y: A);
 }
-struct foo<A: Copy> {
+struct foo<A> {
   x: A,
 }
 

src/test/run-pass/issue-2311-2.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 trait clam<A: Copy> { }
-struct foo<A: Copy> {
+struct foo<A> {
     x: A,
 }
 

src/test/run-pass/issue-2445-b.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-struct c1<T: Copy> {
+struct c1<T> {
     x: T,
 }
 

src/test/run-pass/issue-2445.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-struct c1<T: Copy> {
+struct c1<T> {
     x: T,
 }
 

src/test/run-pass/issue-2718.rs

@@ -34,7 +34,7 @@ pub mod pipes {
         pure fn ne(&self, other: &state) -> bool { !(*self).eq(other) }
     }
 
-    pub type packet<T: Owned> = {
+    pub type packet<T> = {
         mut state: state,
         mut blocked_task: Option<task::Task>,
         mut payload: Option<T>
@@ -157,7 +157,7 @@ pub mod pipes {
         }
     }
 
-    pub struct send_packet<T: Owned> {
+    pub struct send_packet<T> {
         mut p: Option<*packet<T>>,
     }
 
@@ -185,7 +185,7 @@ pub mod pipes {
         }
     }
 
-    pub struct recv_packet<T: Owned> {
+    pub struct recv_packet<T> {
         mut p: Option<*packet<T>>,
     }
 

src/test/run-pass/issue-3149.rs

@@ -22,7 +22,7 @@ pure fn Matrix4<T:Copy Num>(m11: T, m12: T, m13: T, m14: T,
     }
 }
 
-struct Matrix4<T:Copy Num> {
+struct Matrix4<T> {
     m11: T, m12: T, m13: T, m14: T,
     m21: T, m22: T, m23: T, m24: T,
     m31: T, m32: T, m33: T, m34: T,

src/test/run-pass/reflect-visit-data.rs

@@ -29,7 +29,7 @@ fn align(size: uint, align: uint) -> uint {
     ((size + align) - 1u) & !(align - 1u)
 }
 
-enum ptr_visit_adaptor<V: TyVisitor movable_ptr> = Inner<V>;
+enum ptr_visit_adaptor<V> = Inner<V>;
 
 impl<V: TyVisitor movable_ptr> ptr_visit_adaptor<V> {
 

src/test/run-pass/resource-generic.rs

@@ -13,7 +13,7 @@
 
 struct Arg<T> {val: T, fin: extern fn(T)}
 
-struct finish<T: Copy> {
+struct finish<T> {
   arg: Arg<T>
 }
 

src/test/run-pass/send-type-inference.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 // tests that ctrl's type gets inferred properly
-type command<K: Owned, V: Owned> = {key: K, val: V};
+type command<K, V> = {key: K, val: V};
 
 fn cache_server<K: Owned, V: Owned>(c: oldcomm::Chan<oldcomm::Chan<command<K, V>>>) {
     let ctrl = oldcomm::Port();