Rollup merge of #53107 - RalfJung:static-mutex, r=alexcrichton

Remove references to `StaticMutex` which got removed a while ago

`StaticMutex` got removed two years ago with https://github.com/rust-lang/rust/pull/34705, but still got referenced in some comments and even an error explanation.

2 files changed, 4 insertions, 9 deletions

diff --git a/src/libstd/sync/once.rs b/src/libstd/sync/once.rs
index 3abc260b458..f6cb8beae84 100644
--- a/src/libstd/sync/once.rs
+++ b/src/libstd/sync/once.rs
@@ -31,12 +31,10 @@
 // initialization closure panics, the Once enters a "poisoned" state which means
 // that all future calls will immediately panic as well.
 //
-// So to implement this, one might first reach for a `StaticMutex`, but those
-// unfortunately need to be deallocated (e.g. call `destroy()`) to free memory
-// on all OSes (some of the BSDs allocate memory for mutexes). It also gets a
-// lot harder with poisoning to figure out when the mutex needs to be
-// deallocated because it's not after the closure finishes, but after the first
-// successful closure finishes.
+// So to implement this, one might first reach for a `Mutex`, but those cannot
+// be put into a `static`. It also gets a lot harder with poisoning to figure
+// out when the mutex needs to be deallocated because it's not after the closure
+// finishes, but after the first successful closure finishes.
 //
 // All in all, this is instead implemented with atomics and lock-free
 // operations! Whee! Each `Once` has one word of atomic state, and this state is
diff --git a/src/libstd/sys/unix/mutex.rs b/src/libstd/sys/unix/mutex.rs
index 52cf3f97c5c..60b03cdbeb0 100644
--- a/src/libstd/sys/unix/mutex.rs
+++ b/src/libstd/sys/unix/mutex.rs
@@ -49,9 +49,6 @@ impl Mutex {
         // references, we instead create the mutex with type
         // PTHREAD_MUTEX_NORMAL which is guaranteed to deadlock if we try to
         // re-lock it from the same thread, thus avoiding undefined behavior.
-        //
-        // We can't do anything for StaticMutex, but that type is deprecated
-        // anyways.
         let mut attr: libc::pthread_mutexattr_t = mem::uninitialized();
         let r = libc::pthread_mutexattr_init(&mut attr);
         debug_assert_eq!(r, 0);