8 files changed, 19 insertions, 19 deletions
diff --git a/src/libstd/sys/cloudabi/mutex.rs b/src/libstd/sys/cloudabi/mutex.rs
index 4aa25e25052..580ab0e8ad8 100644
--- a/src/libstd/sys/cloudabi/mutex.rs
+++ b/src/libstd/sys/cloudabi/mutex.rs
@@ -53,16 +53,16 @@ pub struct ReentrantMutex {
 }
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex {
             lock: UnsafeCell::new(MaybeUninit::uninit()),
             recursion: UnsafeCell::new(MaybeUninit::uninit()),
         }
     }
 
-    pub unsafe fn init(&mut self) {
-        self.lock = UnsafeCell::new(MaybeUninit::new(AtomicU32::new(abi::LOCK_UNLOCKED.0)));
-        self.recursion = UnsafeCell::new(MaybeUninit::new(0));
+    pub unsafe fn init(&self) {
+        *self.lock.get() = MaybeUninit::new(AtomicU32::new(abi::LOCK_UNLOCKED.0));
+        *self.recursion.get() = MaybeUninit::new(0);
     }
 
     pub unsafe fn try_lock(&self) -> bool {
diff --git a/src/libstd/sys/hermit/mutex.rs b/src/libstd/sys/hermit/mutex.rs
index b5c75f738d2..3d4813209cb 100644
--- a/src/libstd/sys/hermit/mutex.rs
+++ b/src/libstd/sys/hermit/mutex.rs
@@ -46,13 +46,13 @@ pub struct ReentrantMutex {
 }
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { inner: ptr::null() }
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {
-        let _ = abi::recmutex_init(&mut self.inner as *mut *const c_void);
+    pub unsafe fn init(&self) {
+        let _ = abi::recmutex_init(&self.inner as *const *const c_void as *mut _);
     }
 
     #[inline]
diff --git a/src/libstd/sys/sgx/mutex.rs b/src/libstd/sys/sgx/mutex.rs
index eebbea1b285..4911c2f5387 100644
--- a/src/libstd/sys/sgx/mutex.rs
+++ b/src/libstd/sys/sgx/mutex.rs
@@ -75,7 +75,7 @@ impl ReentrantMutex {
     }
 
     #[inline]
-    pub unsafe fn init(&mut self) {}
+    pub unsafe fn init(&self) {}
 
     #[inline]
     pub unsafe fn lock(&self) {
diff --git a/src/libstd/sys/unix/mutex.rs b/src/libstd/sys/unix/mutex.rs
index b38375a2e03..103d87e3d2f 100644
--- a/src/libstd/sys/unix/mutex.rs
+++ b/src/libstd/sys/unix/mutex.rs
@@ -92,11 +92,11 @@ unsafe impl Send for ReentrantMutex {}
 unsafe impl Sync for ReentrantMutex {}
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
     }
 
-    pub unsafe fn init(&mut self) {
+    pub unsafe fn init(&self) {
         let mut attr = MaybeUninit::<libc::pthread_mutexattr_t>::uninit();
         let result = libc::pthread_mutexattr_init(attr.as_mut_ptr());
         debug_assert_eq!(result, 0);
diff --git a/src/libstd/sys/vxworks/mutex.rs b/src/libstd/sys/vxworks/mutex.rs
index b38375a2e03..103d87e3d2f 100644
--- a/src/libstd/sys/vxworks/mutex.rs
+++ b/src/libstd/sys/vxworks/mutex.rs
@@ -92,11 +92,11 @@ unsafe impl Send for ReentrantMutex {}
 unsafe impl Sync for ReentrantMutex {}
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { inner: UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER) }
     }
 
-    pub unsafe fn init(&mut self) {
+    pub unsafe fn init(&self) {
         let mut attr = MaybeUninit::<libc::pthread_mutexattr_t>::uninit();
         let result = libc::pthread_mutexattr_init(attr.as_mut_ptr());
         debug_assert_eq!(result, 0);
diff --git a/src/libstd/sys/wasm/mutex.rs b/src/libstd/sys/wasm/mutex.rs
index 07238d08730..7aaf1b3a343 100644
--- a/src/libstd/sys/wasm/mutex.rs
+++ b/src/libstd/sys/wasm/mutex.rs
@@ -47,11 +47,11 @@ impl Mutex {
 pub struct ReentrantMutex {}
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex {}
     }
 
-    pub unsafe fn init(&mut self) {}
+    pub unsafe fn init(&self) {}
 
     pub unsafe fn lock(&self) {}
 
diff --git a/src/libstd/sys/wasm/mutex_atomics.rs b/src/libstd/sys/wasm/mutex_atomics.rs
index 90c628a19c2..268a53bb564 100644
--- a/src/libstd/sys/wasm/mutex_atomics.rs
+++ b/src/libstd/sys/wasm/mutex_atomics.rs
@@ -80,11 +80,11 @@ unsafe impl Sync for ReentrantMutex {}
 // released when this recursion counter reaches 0.
 
 impl ReentrantMutex {
-    pub unsafe fn uninitialized() -> ReentrantMutex {
+    pub const unsafe fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { owner: AtomicU32::new(0), recursions: UnsafeCell::new(0) }
     }
 
-    pub unsafe fn init(&mut self) {
+    pub unsafe fn init(&self) {
         // nothing to do...
     }
 
diff --git a/src/libstd/sys/windows/mutex.rs b/src/libstd/sys/windows/mutex.rs
index 281eb294c65..63dfc640908 100644
--- a/src/libstd/sys/windows/mutex.rs
+++ b/src/libstd/sys/windows/mutex.rs
@@ -109,7 +109,7 @@ impl Mutex {
             0 => {}
             n => return n as *mut _,
         }
-        let mut re = box ReentrantMutex::uninitialized();
+        let re = box ReentrantMutex::uninitialized();
         re.init();
         let re = Box::into_raw(re);
         match self.lock.compare_and_swap(0, re as usize, Ordering::SeqCst) {
@@ -157,11 +157,11 @@ unsafe impl Send for ReentrantMutex {}
 unsafe impl Sync for ReentrantMutex {}
 
 impl ReentrantMutex {
-    pub fn uninitialized() -> ReentrantMutex {
+    pub const fn uninitialized() -> ReentrantMutex {
         ReentrantMutex { inner: UnsafeCell::new(MaybeUninit::uninit()) }
     }
 
-    pub unsafe fn init(&mut self) {
+    pub unsafe fn init(&self) {
         c::InitializeCriticalSection((&mut *self.inner.get()).as_mut_ptr());
     }