7 files changed, 35 insertions, 8 deletions
diff --git a/src/mutex.rs b/src/mutex.rs
index b36854b..431eedc 100644
--- a/src/mutex.rs
+++ b/src/mutex.rs
@@ -49,5 +49,6 @@ pub struct MutexRef<'a, T: ?Sized + 'a, R: RawMutex>(&'a Mutex<T, R>);
 pub struct MutexGuard<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable + 'key, R: RawMutex> {
 	mutex: MutexRef<'a, T, R>,
 	thread_key: Key,
-	_phantom: PhantomData<&'key ()>,
+	_phantom1: PhantomData<*const ()>, // implement !Send
+	_phantom2: PhantomData<&'key ()>,
 }
diff --git a/src/mutex/guard.rs b/src/mutex/guard.rs
index 9a309b4..5a2a2c1 100644
--- a/src/mutex/guard.rs
+++ b/src/mutex/guard.rs
@@ -61,7 +61,15 @@ impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawMutex> MutexGuard<'a, 'ke
 		Self {
 			mutex: MutexRef(mutex),
 			thread_key,
-			_phantom: PhantomData,
+			_phantom1: PhantomData,
+			_phantom2: PhantomData,
 		}
 	}
 }
+
+unsafe impl<'a, T: ?Sized + 'a, R: RawMutex> Sync for MutexRef<'a, T, R> {}
+
+unsafe impl<'a, 'key: 'a, T: ?Sized + Sync, Key: Keyable + 'key, R: RawMutex> Sync
+	for MutexGuard<'_, 'key, T, Key, R>
+{
+}
diff --git a/src/mutex/mutex.rs b/src/mutex/mutex.rs
index 83600b9..1976e57 100644
--- a/src/mutex/mutex.rs
+++ b/src/mutex/mutex.rs
@@ -227,4 +227,4 @@ impl<T: ?Sized, R: RawMutex> Mutex<T, R> {
 }
 
 unsafe impl<R: RawMutex + Send, T: ?Sized + Send> Send for Mutex<T, R> {}
-unsafe impl<R: RawMutex + Sync, T: ?Sized + Send + Sync> Sync for Mutex<T, R> {}
+unsafe impl<R: RawMutex + Sync, T: ?Sized + Send> Sync for Mutex<T, R> {}
diff --git a/src/rwlock.rs b/src/rwlock.rs
index fb40a71..f11b204 100644
--- a/src/rwlock.rs
+++ b/src/rwlock.rs
@@ -83,7 +83,8 @@ pub struct RwLockWriteRef<'a, T: ?Sized, R: RawRwLock>(&'a RwLock<T, R>);
 pub struct RwLockReadGuard<'a, 'key, T: ?Sized, Key: Keyable + 'key, R: RawRwLock> {
 	rwlock: RwLockReadRef<'a, T, R>,
 	thread_key: Key,
-	_phantom: PhantomData<&'key ()>,
+	_phantom1: PhantomData<&'key ()>,
+	_phantom2: PhantomData<*const ()>,
 }
 
 /// RAII structure used to release the exclusive write access of a lock when
@@ -96,5 +97,6 @@ pub struct RwLockReadGuard<'a, 'key, T: ?Sized, Key: Keyable + 'key, R: RawRwLoc
 pub struct RwLockWriteGuard<'a, 'key, T: ?Sized, Key: Keyable + 'key, R: RawRwLock> {
 	rwlock: RwLockWriteRef<'a, T, R>,
 	thread_key: Key,
-	_phantom: PhantomData<&'key ()>,
+	_phantom1: PhantomData<&'key ()>,
+	_phantom2: PhantomData<*const ()>,
 }
diff --git a/src/rwlock/read_guard.rs b/src/rwlock/read_guard.rs
index d8db9b9..074b0a9 100644
--- a/src/rwlock/read_guard.rs
+++ b/src/rwlock/read_guard.rs
@@ -46,7 +46,15 @@ impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock>
 		Self {
 			rwlock: RwLockReadRef(rwlock),
 			thread_key,
-			_phantom: PhantomData,
+			_phantom1: PhantomData,
+			_phantom2: PhantomData,
 		}
 	}
 }
+
+unsafe impl<'a, T: ?Sized + 'a, R: RawRwLock> Sync for RwLockReadRef<'a, T, R> {}
+
+unsafe impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock> Sync
+	for RwLockReadGuard<'a, 'key, T, Key, R>
+{
+}
diff --git a/src/rwlock/rwlock.rs b/src/rwlock/rwlock.rs
index b1c7ff0..b1c4def 100644
--- a/src/rwlock/rwlock.rs
+++ b/src/rwlock/rwlock.rs
@@ -370,4 +370,4 @@ impl<T: ?Sized, R: RawRwLock> RwLock<T, R> {
 }
 
 unsafe impl<R: RawRwLock + Send, T: ?Sized + Send> Send for RwLock<T, R> {}
-unsafe impl<R: RawRwLock + Sync, T: ?Sized + Send + Sync> Sync for RwLock<T, R> {}
+unsafe impl<R: RawRwLock + Sync, T: ?Sized + Send> Sync for RwLock<T, R> {}
diff --git a/src/rwlock/write_guard.rs b/src/rwlock/write_guard.rs
index dd168bf..9350425 100644
--- a/src/rwlock/write_guard.rs
+++ b/src/rwlock/write_guard.rs
@@ -63,7 +63,15 @@ impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock>
 		Self {
 			rwlock: RwLockWriteRef(rwlock),
 			thread_key,
-			_phantom: PhantomData,
+			_phantom1: PhantomData,
+			_phantom2: PhantomData,
 		}
 	}
 }
+
+unsafe impl<'a, T: ?Sized + 'a, R: RawRwLock> Sync for RwLockWriteRef<'a, T, R> {}
+
+unsafe impl<'a, 'key: 'a, T: ?Sized + 'a, Key: Keyable, R: RawRwLock> Sync
+	for RwLockWriteGuard<'a, 'key, T, Key, R>
+{
+}