Auto merge of #100576 - joboet:movable_const_remutex, r=Mark-Simulacrum

Make `ReentrantMutex` movable and `const`

As `MovableMutex` is now `const`, it can be used to simplify the implementation and interface of the internal reentrant mutex type. Consequently, the standard error stream does not need to be wrapped in `OnceLock` and `OnceLock::get_or_init_pin()` can be removed.

8 files changed, 1 insertions, 24 deletions

diff --git a/library/std/src/sys/hermit/mutex.rs b/library/std/src/sys/hermit/mutex.rs
index eb15a04ffcf..e0184eb5baf 100644
--- a/library/std/src/sys/hermit/mutex.rs
+++ b/library/std/src/sys/hermit/mutex.rs
@@ -175,9 +175,6 @@ impl Mutex {
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {}
-
-    #[inline]
     pub unsafe fn lock(&self) {
         loop {
             let mut guard = self.inner.lock();
diff --git a/library/std/src/sys/itron/mutex.rs b/library/std/src/sys/itron/mutex.rs
index 715e94c3b3d..085662e6d44 100644
--- a/library/std/src/sys/itron/mutex.rs
+++ b/library/std/src/sys/itron/mutex.rs
@@ -31,12 +31,6 @@ impl Mutex {
         Mutex { mtx: SpinIdOnceCell::new() }
     }
 
-    pub unsafe fn init(&mut self) {
-        // Initialize `self.mtx` eagerly
-        let id = new_mtx().unwrap_or_else(|e| fail(e, &"acre_mtx"));
-        unsafe { self.mtx.set_unchecked((id, ())) };
-    }
-
     /// Get the inner mutex's ID, which is lazily created.
     fn raw(&self) -> abi::ID {
         match self.mtx.get_or_try_init(|| new_mtx().map(|id| (id, ()))) {
diff --git a/library/std/src/sys/sgx/mutex.rs b/library/std/src/sys/sgx/mutex.rs
index 513cd77fd2a..aa747d56b0d 100644
--- a/library/std/src/sys/sgx/mutex.rs
+++ b/library/std/src/sys/sgx/mutex.rs
@@ -21,9 +21,6 @@ impl Mutex {
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {}
-
-    #[inline]
     pub unsafe fn lock(&self) {
         let mut guard = self.inner.lock();
         if *guard.lock_var() {
diff --git a/library/std/src/sys/unix/locks/fuchsia_mutex.rs b/library/std/src/sys/unix/locks/fuchsia_mutex.rs
index dbb9829bb66..117611ce43f 100644
--- a/library/std/src/sys/unix/locks/fuchsia_mutex.rs
+++ b/library/std/src/sys/unix/locks/fuchsia_mutex.rs
@@ -86,9 +86,6 @@ impl Mutex {
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {}
-
-    #[inline]
     pub unsafe fn try_lock(&self) -> bool {
         let thread_self = zx_thread_self();
         self.futex.compare_exchange(UNLOCKED, to_state(thread_self), Acquire, Relaxed).is_ok()
diff --git a/library/std/src/sys/unix/locks/futex_mutex.rs b/library/std/src/sys/unix/locks/futex_mutex.rs
index 1b5be46c605..33b13dad4d6 100644
--- a/library/std/src/sys/unix/locks/futex_mutex.rs
+++ b/library/std/src/sys/unix/locks/futex_mutex.rs
@@ -20,9 +20,6 @@ impl Mutex {
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {}
-
-    #[inline]
     pub unsafe fn try_lock(&self) -> bool {
         self.futex.compare_exchange(0, 1, Acquire, Relaxed).is_ok()
     }
diff --git a/library/std/src/sys/unix/locks/pthread_mutex.rs b/library/std/src/sys/unix/locks/pthread_mutex.rs
index 98afee69ba6..5964935ddb5 100644
--- a/library/std/src/sys/unix/locks/pthread_mutex.rs
+++ b/library/std/src/sys/unix/locks/pthread_mutex.rs
@@ -52,7 +52,7 @@ impl Mutex {
         Mutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
     }
     #[inline]
-    pub unsafe fn init(&mut self) {
+    unsafe fn init(&mut self) {
         // Issue #33770
         //
         // A pthread mutex initialized with PTHREAD_MUTEX_INITIALIZER will have
diff --git a/library/std/src/sys/unsupported/locks/mutex.rs b/library/std/src/sys/unsupported/locks/mutex.rs
index d7cb12e0cf9..2be0b34b985 100644
--- a/library/std/src/sys/unsupported/locks/mutex.rs
+++ b/library/std/src/sys/unsupported/locks/mutex.rs
@@ -17,9 +17,6 @@ impl Mutex {
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {}
-
-    #[inline]
     pub unsafe fn lock(&self) {
         assert_eq!(self.locked.replace(true), false, "cannot recursively acquire mutex");
     }
diff --git a/library/std/src/sys/windows/locks/mutex.rs b/library/std/src/sys/windows/locks/mutex.rs
index f91e8f9f59a..91207f5f466 100644
--- a/library/std/src/sys/windows/locks/mutex.rs
+++ b/library/std/src/sys/windows/locks/mutex.rs
@@ -37,8 +37,6 @@ impl Mutex {
     pub const fn new() -> Mutex {
         Mutex { srwlock: UnsafeCell::new(c::SRWLOCK_INIT) }
     }
-    #[inline]
-    pub unsafe fn init(&mut self) {}
 
     #[inline]
     pub unsafe fn lock(&self) {