std: Stabilize the prelude module

This commit is an implementation of [RFC 503][rfc] which is a stabilization
story for the prelude. Most of the RFC was directly applied, removing reexports.
Some reexports are kept around, however:

* `range` remains until range syntax has landed to reduce churn.
* `Path` and `GenericPath` remain until path reform lands. This is done to
  prevent many imports of `GenericPath` which will soon be removed.
* All `io` traits remain until I/O reform lands so imports can be rewritten all
  at once to `std::io::prelude::*`.

This is a breaking change because many prelude reexports have been removed, and
the RFC can be consulted for the exact list of removed reexports, as well as to
find the locations of where to import them.

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0503-prelude-stabilization.md
[breaking-change]

Closes #20068

1 files changed, 9 insertions, 7 deletions

diff --git a/src/libstd/sync/semaphore.rs b/src/libstd/sync/semaphore.rs
index 574b0f22bee..382caa2cf4a 100644
--- a/src/libstd/sync/semaphore.rs
+++ b/src/libstd/sync/semaphore.rs
@@ -104,10 +104,12 @@ impl<'a> Drop for SemaphoreGuard<'a> {
 
 #[cfg(test)]
 mod tests {
-    use prelude::*;
+    use prelude::v1::*;
 
     use sync::Arc;
     use super::Semaphore;
+    use comm::channel;
+    use thread::Thread;
 
     #[test]
     fn test_sem_acquire_release() {
@@ -127,7 +129,7 @@ mod tests {
     fn test_sem_as_mutex() {
         let s = Arc::new(Semaphore::new(1));
         let s2 = s.clone();
-        spawn(move|| {
+        let _t = Thread::spawn(move|| {
             let _g = s2.access();
         });
         let _g = s.access();
@@ -139,7 +141,7 @@ mod tests {
         let (tx, rx) = channel();
         let s = Arc::new(Semaphore::new(0));
         let s2 = s.clone();
-        spawn(move|| {
+        let _t = Thread::spawn(move|| {
             s2.acquire();
             tx.send(());
         });
@@ -150,7 +152,7 @@ mod tests {
         let (tx, rx) = channel();
         let s = Arc::new(Semaphore::new(0));
         let s2 = s.clone();
-        spawn(move|| {
+        let _t = Thread::spawn(move|| {
             s2.release();
             let _ = rx.recv();
         });
@@ -166,7 +168,7 @@ mod tests {
         let s2 = s.clone();
         let (tx1, rx1) = channel();
         let (tx2, rx2) = channel();
-        spawn(move|| {
+        let _t = Thread::spawn(move|| {
             let _g = s2.access();
             let _ = rx2.recv();
             tx1.send(());
@@ -183,11 +185,11 @@ mod tests {
         let (tx, rx) = channel();
         {
             let _g = s.access();
-            spawn(move|| {
+            Thread::spawn(move|| {
                 tx.send(());
                 drop(s2.access());
                 tx.send(());
-            });
+            }).detach();
             rx.recv(); // wait for child to come alive
         }
         rx.recv(); // wait for child to be done