make spawned fn copy mode so that bare fns can be used

Author: nikomatsakis

src/libcore/task.rs

@@ -110,7 +110,7 @@ Returns:
 
 A handle to the new task
 */
-fn spawn(-f: sendfn()) -> task {
+fn spawn(+f: sendfn()) -> task {
     spawn_inner(f, none)
 }
 
@@ -139,7 +139,7 @@ A task that sends notification upon termination
 */
 type joinable_task = (task, comm::port<task_notification>);
 
-fn spawn_joinable(-f: sendfn()) -> joinable_task {
+fn spawn_joinable(+f: sendfn()) -> joinable_task {
     let notify_port = comm::port();
     let notify_chan = comm::chan(notify_port);
     let task = spawn_inner(f, some(notify_chan));
@@ -189,6 +189,29 @@ tag task_notification {
     exit(task, task_result);
 }
 
+/*
+type connected_fn<ToCh, FrCh> = sendfn(comm::chan<FrCh>, comm::port<ToCh>);
+type connected_task<ToCh, FrCh> = {
+    port: comm::port<FrCh>,
+    chan: comm::chan<ToCh>,
+    task: task
+};
+fn spawn_connected<ToCh:send, FrCh:send>(f: connected_fn<ToCh, FrCh>)
+    -> connected_fn {
+    let from_child_port = comm::port<FrCh>();
+    let from_child_chan = comm::chan(from_child_port);
+    let get_to_child_port = comm::port<comm::chan<ToCh>>();
+    let get_to_child_chan = comm::chan(to_child_port);
+    let child_task = spawn(sendfn[move f]() {
+        let to_child_port = comm::port<ToCh>();
+        comm::send(get_to_child_chan, to_child_port);
+        f(from_child_chan, to_child_port);
+    });
+    let to_child_chan = comm::recv(get_out);
+    ret {port: from_child_port, chan: to_child_chan, task: child_task};
+}
+*/
+
 /* Section: Operations */
 
 /*

src/test/run-fail/task-spawn-barefn.rs

@@ -0,0 +1,11 @@
+// error-pattern:Ensure that the child task runs by failing
+
+fn main() {
+    // the purpose of this test is to make sure that task::spawn()
+    // works when provided with a bare function:
+    task::spawn(startfn);
+}
+
+fn startfn() {
+    assert str::is_empty("Ensure that the child task runs by failing");
+}