auto merge of #14069 : alexcrichton/rust/cast-module, r=brson

This commit revisits the `cast` module in libcore and libstd, and scrutinizes
all functions inside of it. The result was to remove the `cast` module entirely,
folding all functionality into the `mem` module. Specifically, this is the fate
of each function in the `cast` module.

* transmute - This function was moved to `mem`, but it is now marked as
              #[unstable]. This is due to planned changes to the `transmute`
              function and how it can be invoked (see the #[unstable] comment).
              For more information, see RFC 5 and #12898

* transmute_copy - This function was moved to `mem`, with clarification that is
                   is not an error to invoke it with T/U that are different
                   sizes, but rather that it is strongly discouraged. This
                   function is now #[stable]

* forget - This function was moved to `mem` and marked #[stable]

* bump_box_refcount - This function was removed due to the deprecation of
                      managed boxes as well as its questionable utility.

* transmute_mut - This function was previously deprecated, and removed as part
                  of this commit.

* transmute_mut_unsafe - This function doesn't serve much of a purpose when it
                         can be achieved with an `as` in safe code, so it was
                         removed.

* transmute_lifetime - This function was removed because it is likely a strong
                       indication that code is incorrect in the first place.

* transmute_mut_lifetime - This function was removed for the same reasons as
                           `transmute_lifetime`

* copy_lifetime - This function was moved to `mem`, but it is marked
                  `#[unstable]` now due to the likelihood of being removed in
                  the future if it is found to not be very useful.

* copy_mut_lifetime - This function was also moved to `mem`, but had the same
                      treatment as `copy_lifetime`.

* copy_lifetime_vec - This function was removed because it is not used today,
                      and its existence is not necessary with DST
                      (copy_lifetime will suffice).

In summary, the cast module was stripped down to these functions, and then the
functions were moved to the `mem` module.

    transmute - #[unstable]
    transmute_copy - #[stable]
    forget - #[stable]
    copy_lifetime - #[unstable]
    copy_mut_lifetime - #[unstable]

1 files changed, 11 insertions, 11 deletions

diff --git a/src/libstd/rt/task.rs b/src/libstd/rt/task.rs
index 77bcb7b9904..cd0445056b2 100644
--- a/src/libstd/rt/task.rs
+++ b/src/libstd/rt/task.rs
@@ -14,7 +14,6 @@
 //! to implement this.
 
 use any::AnyOwnExt;
-use cast;
 use cleanup;
 use clone::Clone;
 use comm::Sender;
@@ -22,6 +21,7 @@ use io::Writer;
 use iter::{Iterator, Take};
 use kinds::Send;
 use local_data;
+use mem;
 use ops::Drop;
 use option::{Option, Some, None};
 use owned::Box;
@@ -116,7 +116,7 @@ impl Task {
         // Unsafely get a handle to the task so we can continue to use it after
         // putting it in tls (so we can invoke the unwinder).
         let handle: *mut Task = unsafe {
-            *cast::transmute::<&Box<Task>, &*mut Task>(&self)
+            *mem::transmute::<&Box<Task>, &*mut Task>(&self)
         };
         Local::put(self);
 
@@ -222,13 +222,13 @@ impl Task {
         //      crops up.
         unsafe {
             let imp = self.imp.take_unwrap();
-            let &(vtable, _): &(uint, uint) = cast::transmute(&imp);
+            let &(vtable, _): &(uint, uint) = mem::transmute(&imp);
             match imp.wrap().move::<T>() {
                 Ok(t) => Some(t),
                 Err(t) => {
-                    let (_, obj): (uint, uint) = cast::transmute(t);
+                    let (_, obj): (uint, uint) = mem::transmute(t);
                     let obj: Box<Runtime:Send> =
-                        cast::transmute((vtable, obj));
+                        mem::transmute((vtable, obj));
                     self.put_runtime(obj);
                     None
                 }
@@ -317,7 +317,7 @@ impl BlockedTask {
             Shared(arc) => unsafe {
                 match (*arc.get()).swap(0, SeqCst) {
                     0 => None,
-                    n => Some(cast::transmute(n)),
+                    n => Some(mem::transmute(n)),
                 }
             }
         }
@@ -343,7 +343,7 @@ impl BlockedTask {
     pub fn make_selectable(self, num_handles: uint) -> Take<BlockedTasks> {
         let arc = match self {
             Owned(task) => {
-                let flag = unsafe { AtomicUint::new(cast::transmute(task)) };
+                let flag = unsafe { AtomicUint::new(mem::transmute(task)) };
                 UnsafeArc::new(flag)
             }
             Shared(arc) => arc.clone(),
@@ -357,12 +357,12 @@ impl BlockedTask {
     pub unsafe fn cast_to_uint(self) -> uint {
         match self {
             Owned(task) => {
-                let blocked_task_ptr: uint = cast::transmute(task);
+                let blocked_task_ptr: uint = mem::transmute(task);
                 rtassert!(blocked_task_ptr & 0x1 == 0);
                 blocked_task_ptr
             }
             Shared(arc) => {
-                let blocked_task_ptr: uint = cast::transmute(box arc);
+                let blocked_task_ptr: uint = mem::transmute(box arc);
                 rtassert!(blocked_task_ptr & 0x1 == 0);
                 blocked_task_ptr | 0x1
             }
@@ -374,10 +374,10 @@ impl BlockedTask {
     #[inline]
     pub unsafe fn cast_from_uint(blocked_task_ptr: uint) -> BlockedTask {
         if blocked_task_ptr & 0x1 == 0 {
-            Owned(cast::transmute(blocked_task_ptr))
+            Owned(mem::transmute(blocked_task_ptr))
         } else {
             let ptr: Box<UnsafeArc<AtomicUint>> =
-                cast::transmute(blocked_task_ptr & !1);
+                mem::transmute(blocked_task_ptr & !1);
             Shared(*ptr)
         }
     }