Use boxed functions instead of transmute

... to convert between Box and raw pointers. E. g. use

```
let b: Box<Foo> = Box::from_raw(p);
```

instead of

```
let b: Box<Foo> = mem::transmute(p);
```

Patch also changes closure release code in `src/libstd/sys/unix/thread.rs`
when `pthread_create` failed. Raw pointer was transmuted to box of
`FnOnce()` instead of `Thunk`. This code was probably never executed,
because `pthread_create` rarely fails in practice.

11 files changed, 42 insertions, 31 deletions

diff --git a/src/libstd/old_io/stdio.rs b/src/libstd/old_io/stdio.rs
index e3d0232684f..56a707c24a6 100644
--- a/src/libstd/old_io/stdio.rs
+++ b/src/libstd/old_io/stdio.rs
@@ -27,6 +27,7 @@
 
 use self::StdSource::*;
 
+use boxed;
 use boxed::Box;
 use cell::RefCell;
 use clone::Clone;
@@ -218,7 +219,7 @@ impl Reader for StdinReader {
 /// See `stdout()` for more notes about this function.
 pub fn stdin() -> StdinReader {
     // We're following the same strategy as kimundi's lazy_static library
-    static mut STDIN: *const StdinReader = 0 as *const StdinReader;
+    static mut STDIN: *mut StdinReader = 0 as *mut StdinReader;
     static ONCE: Once = ONCE_INIT;
 
     unsafe {
@@ -235,12 +236,12 @@ pub fn stdin() -> StdinReader {
             let stdin = StdinReader {
                 inner: Arc::new(Mutex::new(RaceBox(stdin)))
             };
-            STDIN = mem::transmute(box stdin);
+            STDIN = boxed::into_raw(box stdin);
 
             // Make sure to free it at exit
             rt::at_exit(|| {
-                mem::transmute::<_, Box<StdinReader>>(STDIN);
-                STDIN = ptr::null();
+                Box::from_raw(STDIN);
+                STDIN = ptr::null_mut();
             });
         });
 
diff --git a/src/libstd/rt/at_exit_imp.rs b/src/libstd/rt/at_exit_imp.rs
index 72486fc55d4..08755ba829f 100644
--- a/src/libstd/rt/at_exit_imp.rs
+++ b/src/libstd/rt/at_exit_imp.rs
@@ -14,9 +14,9 @@
 
 use core::prelude::*;
 
+use boxed;
 use boxed::Box;
 use vec::Vec;
-use mem;
 use thunk::Thunk;
 use sys_common::mutex::{Mutex, MUTEX_INIT};
 
@@ -32,7 +32,7 @@ static mut QUEUE: *mut Queue = 0 as *mut Queue;
 unsafe fn init() {
     if QUEUE.is_null() {
         let state: Box<Queue> = box Vec::new();
-        QUEUE = mem::transmute(state);
+        QUEUE = boxed::into_raw(state);
     } else {
         // can't re-init after a cleanup
         rtassert!(QUEUE as uint != 1);
@@ -57,7 +57,7 @@ pub fn cleanup() {
 
         // If we never called init, not need to cleanup!
         if queue as uint != 0 {
-            let queue: Box<Queue> = mem::transmute(queue);
+            let queue: Box<Queue> = Box::from_raw(queue);
             for to_run in *queue {
                 to_run.invoke(());
             }
diff --git a/src/libstd/rt/unwind.rs b/src/libstd/rt/unwind.rs
index 1f5eb3af695..4dda3ea8c99 100644
--- a/src/libstd/rt/unwind.rs
+++ b/src/libstd/rt/unwind.rs
@@ -60,6 +60,7 @@
 use prelude::v1::*;
 
 use any::Any;
+use boxed;
 use cell::Cell;
 use cmp;
 use panicking;
@@ -173,7 +174,8 @@ fn rust_panic(cause: Box<Any + Send + 'static>) -> ! {
             },
             cause: Some(cause),
         };
-        let error = uw::_Unwind_RaiseException(mem::transmute(exception));
+        let exception_param = boxed::into_raw(exception) as *mut uw::_Unwind_Exception;
+        let error = uw::_Unwind_RaiseException(exception_param);
         rtabort!("Could not unwind stack, error = {}", error as int)
     }
 
@@ -181,7 +183,7 @@ fn rust_panic(cause: Box<Any + Send + 'static>) -> ! {
                                 exception: *mut uw::_Unwind_Exception) {
         rtdebug!("exception_cleanup()");
         unsafe {
-            let _: Box<Exception> = mem::transmute(exception);
+            let _: Box<Exception> = Box::from_raw(exception as *mut Exception);
         }
     }
 }
diff --git a/src/libstd/sync/mpsc/mpsc_queue.rs b/src/libstd/sync/mpsc/mpsc_queue.rs
index 6eb7c8c5961..59fa2e6bc9a 100644
--- a/src/libstd/sync/mpsc/mpsc_queue.rs
+++ b/src/libstd/sync/mpsc/mpsc_queue.rs
@@ -44,8 +44,8 @@ pub use self::PopResult::*;
 
 use core::prelude::*;
 
+use alloc::boxed;
 use alloc::boxed::Box;
-use core::mem;
 use core::ptr;
 use core::cell::UnsafeCell;
 
@@ -82,7 +82,7 @@ unsafe impl<T: Send> Sync for Queue<T> { }
 
 impl<T> Node<T> {
     unsafe fn new(v: Option<T>) -> *mut Node<T> {
-        mem::transmute(box Node {
+        boxed::into_raw(box Node {
             next: AtomicPtr::new(ptr::null_mut()),
             value: v,
         })
@@ -129,7 +129,7 @@ impl<T: Send> Queue<T> {
                 assert!((*tail).value.is_none());
                 assert!((*next).value.is_some());
                 let ret = (*next).value.take().unwrap();
-                let _: Box<Node<T>> = mem::transmute(tail);
+                let _: Box<Node<T>> = Box::from_raw(tail);
                 return Data(ret);
             }
 
@@ -146,7 +146,7 @@ impl<T: Send> Drop for Queue<T> {
             let mut cur = *self.tail.get();
             while !cur.is_null() {
                 let next = (*cur).next.load(Ordering::Relaxed);
-                let _: Box<Node<T>> = mem::transmute(cur);
+                let _: Box<Node<T>> = Box::from_raw(cur);
                 cur = next;
             }
         }
diff --git a/src/libstd/sync/mpsc/spsc_queue.rs b/src/libstd/sync/mpsc/spsc_queue.rs
index f111e13975f..7b5c614536d 100644
--- a/src/libstd/sync/mpsc/spsc_queue.rs
+++ b/src/libstd/sync/mpsc/spsc_queue.rs
@@ -37,8 +37,8 @@
 
 use core::prelude::*;
 
+use alloc::boxed;
 use alloc::boxed::Box;
-use core::mem;
 use core::ptr;
 use core::cell::UnsafeCell;
 
@@ -81,7 +81,7 @@ unsafe impl<T: Send> Sync for Queue<T> { }
 impl<T: Send> Node<T> {
     fn new() -> *mut Node<T> {
         unsafe {
-            mem::transmute(box Node {
+            boxed::into_raw(box Node {
                 value: None,
                 next: AtomicPtr::new(ptr::null_mut::<Node<T>>()),
             })
@@ -200,7 +200,7 @@ impl<T: Send> Queue<T> {
                           .next.store(next, Ordering::Relaxed);
                     // We have successfully erased all references to 'tail', so
                     // now we can safely drop it.
-                    let _: Box<Node<T>> = mem::transmute(tail);
+                    let _: Box<Node<T>> = Box::from_raw(tail);
                 }
             }
             return ret;
@@ -233,7 +233,7 @@ impl<T: Send> Drop for Queue<T> {
             let mut cur = *self.first.get();
             while !cur.is_null() {
                 let next = (*cur).next.load(Ordering::Relaxed);
-                let _n: Box<Node<T>> = mem::transmute(cur);
+                let _n: Box<Node<T>> = Box::from_raw(cur);
                 cur = next;
             }
         }
diff --git a/src/libstd/sys/common/helper_thread.rs b/src/libstd/sys/common/helper_thread.rs
index dc1ae85efe0..5faaa928ee9 100644
--- a/src/libstd/sys/common/helper_thread.rs
+++ b/src/libstd/sys/common/helper_thread.rs
@@ -22,8 +22,8 @@
 
 use prelude::v1::*;
 
+use boxed;
 use cell::UnsafeCell;
-use mem;
 use ptr;
 use rt;
 use sync::{StaticMutex, StaticCondvar};
@@ -88,7 +88,7 @@ impl<M: Send> Helper<M> {
             let _guard = self.lock.lock().unwrap();
             if !*self.initialized.get() {
                 let (tx, rx) = channel();
-                *self.chan.get() = mem::transmute(box tx);
+                *self.chan.get() = boxed::into_raw(box tx);
                 let (receive, send) = helper_signal::new();
                 *self.signal.get() = send as uint;
 
@@ -132,7 +132,7 @@ impl<M: Send> Helper<M> {
             let mut guard = self.lock.lock().unwrap();
 
             // Close the channel by destroying it
-            let chan: Box<Sender<M>> = mem::transmute(*self.chan.get());
+            let chan: Box<Sender<M>> = Box::from_raw(*self.chan.get());
             *self.chan.get() = ptr::null_mut();
             drop(chan);
             helper_signal::signal(*self.signal.get() as helper_signal::signal);
diff --git a/src/libstd/sys/common/thread.rs b/src/libstd/sys/common/thread.rs
index b725b6c7e6e..731617858e9 100644
--- a/src/libstd/sys/common/thread.rs
+++ b/src/libstd/sys/common/thread.rs
@@ -27,7 +27,7 @@ pub fn start_thread(main: *mut libc::c_void) -> thread::rust_thread_return {
     unsafe {
         stack::record_os_managed_stack_bounds(0, usize::MAX);
         let handler = stack_overflow::Handler::new();
-        let f: Box<Thunk> = mem::transmute(main);
+        let f: Box<Thunk> = Box::from_raw(main as *mut Thunk);
         f.invoke(());
         drop(handler);
         mem::transmute(0 as thread::rust_thread_return)
diff --git a/src/libstd/sys/unix/thread.rs b/src/libstd/sys/unix/thread.rs
index c42d6d0e641..f4791d39da1 100644
--- a/src/libstd/sys/unix/thread.rs
+++ b/src/libstd/sys/unix/thread.rs
@@ -11,6 +11,7 @@
 use core::prelude::*;
 
 use io;
+use boxed;
 use boxed::Box;
 use cmp;
 use mem;
@@ -241,13 +242,15 @@ pub unsafe fn create(stack: uint, p: Thunk) -> io::Result<rust_thread> {
         },
     };
 
-    let arg: *mut libc::c_void = mem::transmute(box p); // must box since sizeof(p)=2*uint
+    // must box since sizeof(p)=2*uint
+    let raw_p = boxed::into_raw(box p);
+    let arg = raw_p as *mut libc::c_void;
     let ret = pthread_create(&mut native, &attr, thread_start, arg);
     assert_eq!(pthread_attr_destroy(&mut attr), 0);
 
     if ret != 0 {
         // be sure to not leak the closure
-        let _p: Box<Box<FnOnce()+Send>> = mem::transmute(arg);
+        let _p: Box<Thunk> = Box::from_raw(raw_p);
         Err(io::Error::from_os_error(ret))
     } else {
         Ok(native)
diff --git a/src/libstd/sys/windows/thread.rs b/src/libstd/sys/windows/thread.rs
index f3a27877e5c..7fe8dce1a3e 100644
--- a/src/libstd/sys/windows/thread.rs
+++ b/src/libstd/sys/windows/thread.rs
@@ -10,6 +10,8 @@
 
 use prelude::v1::*;
 
+use boxed;
+use boxed::Box;
 use cmp;
 use io;
 use mem;
@@ -45,7 +47,8 @@ pub mod guard {
 }
 
 pub unsafe fn create(stack: uint, p: Thunk) -> io::Result<rust_thread> {
-    let arg: *mut libc::c_void = mem::transmute(box p);
+    let raw_p = boxed::into_raw(box p);
+    let arg = raw_p as *mut libc::c_void;
     // FIXME On UNIX, we guard against stack sizes that are too small but
     // that's because pthreads enforces that stacks are at least
     // PTHREAD_STACK_MIN bytes big.  Windows has no such lower limit, it's
@@ -61,7 +64,7 @@ pub unsafe fn create(stack: uint, p: Thunk) -> io::Result<rust_thread> {
 
     if ret as uint == 0 {
         // be sure to not leak the closure
-        let _p: Box<Thunk> = mem::transmute(arg);
+        let _p: Box<Thunk> = Box::from_raw(raw_p);
         Err(io::Error::last_os_error())
     } else {
         Ok(ret)
diff --git a/src/libstd/sys/windows/thread_local.rs b/src/libstd/sys/windows/thread_local.rs
index 0c24ab1fa09..cf942b5d025 100644
--- a/src/libstd/sys/windows/thread_local.rs
+++ b/src/libstd/sys/windows/thread_local.rs
@@ -133,13 +133,13 @@ unsafe fn init_dtors() {
     if !DTORS.is_null() { return }
 
     let dtors = box Vec::<(Key, Dtor)>::new();
-    DTORS = mem::transmute(dtors);
+    DTORS = boxed::into_raw(dtors);
 
     rt::at_exit(move|| {
         DTOR_LOCK.lock();
         let dtors = DTORS;
         DTORS = ptr::null_mut();
-        mem::transmute::<_, Box<Vec<(Key, Dtor)>>>(dtors);
+        Boxed::from_raw(dtors);
         assert!(DTORS.is_null()); // can't re-init after destructing
         DTOR_LOCK.unlock();
     });
diff --git a/src/libstd/thread_local/mod.rs b/src/libstd/thread_local/mod.rs
index 2ed296e081c..9549ae14b88 100644
--- a/src/libstd/thread_local/mod.rs
+++ b/src/libstd/thread_local/mod.rs
@@ -330,6 +330,7 @@ impl<T: 'static> Key<T> {
 mod imp {
     use prelude::v1::*;
 
+    use alloc::boxed;
     use cell::UnsafeCell;
     use intrinsics;
     use ptr;
@@ -422,14 +423,14 @@ mod imp {
         type List = Vec<(*mut u8, unsafe extern fn(*mut u8))>;
         if DTORS.get().is_null() {
             let v: Box<List> = box Vec::new();
-            DTORS.set(mem::transmute(v));
+            DTORS.set(boxed::into_raw(v) as *mut u8);
         }
         let list: &mut List = &mut *(DTORS.get() as *mut List);
         list.push((t, dtor));
 
         unsafe extern fn run_dtors(mut ptr: *mut u8) {
             while !ptr.is_null() {
-                let list: Box<List> = mem::transmute(ptr);
+                let list: Box<List> = Box::from_raw(ptr as *mut List);
                 for &(ptr, dtor) in &*list {
                     dtor(ptr);
                 }
@@ -467,6 +468,7 @@ mod imp {
 mod imp {
     use prelude::v1::*;
 
+    use alloc::boxed;
     use cell::UnsafeCell;
     use mem;
     use ptr;
@@ -517,7 +519,7 @@ mod imp {
                 key: self,
                 value: mem::transmute_copy(&self.inner),
             };
-            let ptr: *mut Value<T> = mem::transmute(ptr);
+            let ptr: *mut Value<T> = boxed::into_raw(ptr);
             self.os.set(ptr as *mut u8);
             Some(&mut (*ptr).value as *mut T)
         }
@@ -533,7 +535,7 @@ mod imp {
         //
         // Note that to prevent an infinite loop we reset it back to null right
         // before we return from the destructor ourselves.
-        let ptr: Box<Value<T>> = mem::transmute(ptr);
+        let ptr: Box<Value<T>> = Box::from_raw(ptr as *mut Value<T>);
         let key = ptr.key;
         key.os.set(1 as *mut u8);
         drop(ptr);