diff --git a/src/libcore/comm.rs b/src/libcore/comm.rs
index 4fcdad60146..38bdc407547 100644
--- a/src/libcore/comm.rs
+++ b/src/libcore/comm.rs
@@ -1,3 +1,6 @@
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
 /*!
  * Communication between tasks
  *
@@ -162,7 +165,7 @@ fn chan<T: send>(p: port<T>) -> chan<T> {
  * Sends data over a channel. The sent data is moved into the channel,
  * whereupon the caller loses access to it.
  */
-fn send<T: send>(ch: chan<T>, -data: T) {
+fn send<T: send>(ch: chan<T>, +data: T) {
     let chan_t(p) = ch;
     let data_ptr = ptr::addr_of(data) as *();
     let res = rustrt::rust_port_id_send(p, data_ptr);
diff --git a/src/libcore/libc.rs b/src/libcore/libc.rs
index 740a78a6d9c..fc87d64e786 100644
--- a/src/libcore/libc.rs
+++ b/src/libcore/libc.rs
@@ -1,3 +1,6 @@
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
 /*!
  * Bindings for libc.
  *
diff --git a/src/libcore/priv.rs b/src/libcore/priv.rs
index a844a0d6e13..01a7936ca26 100644
--- a/src/libcore/priv.rs
+++ b/src/libcore/priv.rs
@@ -1,3 +1,7 @@
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
+
 #[doc(hidden)];
 
 export chan_from_global_ptr, weaken_task;
diff --git a/src/libcore/rt.rs b/src/libcore/rt.rs
index 0b4038656ef..7fd646d6bf8 100644
--- a/src/libcore/rt.rs
+++ b/src/libcore/rt.rs
@@ -1,3 +1,6 @@
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
 //! Runtime calls emitted by the compiler.
 
 import libc::c_char;
diff --git a/src/libstd/arc.rs b/src/libstd/arc.rs
index 8ab74444f6f..8d6c7ce5d29 100644
--- a/src/libstd/arc.rs
+++ b/src/libstd/arc.rs
@@ -1,3 +1,6 @@
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
 /**
  * Concurrency-enabled mechanisms for sharing mutable and/or immutable state
  * between tasks.
diff --git a/src/libstd/sync.rs b/src/libstd/sync.rs
index 041e28cd795..4233c351cf1 100644
--- a/src/libstd/sync.rs
+++ b/src/libstd/sync.rs
@@ -1,3 +1,6 @@
+// NB: transitionary, de-mode-ing.
+#[forbid(deprecated_mode)];
+#[forbid(deprecated_pattern)];
 /**
  * The concurrency primitives you know and love.
  *
@@ -836,7 +839,7 @@ mod tests {
         }
     }
     #[cfg(test)]
-    fn test_rwlock_exclusion(x: ~rwlock, mode1: rwlock_mode,
+    fn test_rwlock_exclusion(+x: ~rwlock, mode1: rwlock_mode,
                              mode2: rwlock_mode) {
         // Test mutual exclusion between readers and writers. Just like the
         // mutex mutual exclusion test, a ways above.
@@ -881,7 +884,7 @@ mod tests {
         test_rwlock_exclusion(~rwlock(), downgrade, downgrade);
     }
     #[cfg(test)]
-    fn test_rwlock_handshake(x: ~rwlock, mode1: rwlock_mode,
+    fn test_rwlock_handshake(+x: ~rwlock, mode1: rwlock_mode,
                              mode2: rwlock_mode, make_mode2_go_first: bool) {
         // Much like sem_multi_resource.
         let x2 = ~x.clone();