Add rust lint CI job.

rust/lib/mammoth/src/sync.rs

@@ -50,7 +50,7 @@ impl<T> DerefMut for MutexGuard<'_, T> {
     }
 }
 
-impl<T> Mutex<T> {
+impl<'a, T> Mutex<T> {
     pub fn new(data: T) -> Mutex<T> {
         Mutex {
             cap: syscall::mutex_create().unwrap(),
@@ -58,7 +58,7 @@ impl<T> Mutex<T> {
         }
     }
 
-    pub fn lock(&self) -> MutexGuard<T> {
+    pub fn lock(&'a self) -> MutexGuard<'a, T> {
         syscall::mutex_lock(&self.cap).unwrap();
 
         MutexGuard { mutex: self }
@@ -70,3 +70,12 @@ impl<T> Drop for MutexGuard<'_, T> {
         syscall::mutex_release(&self.mutex.cap).unwrap();
     }
 }
+
+impl<T> Default for Mutex<T>
+where
+    T: Default,
+{
+    fn default() -> Self {
+        Self::new(T::default())
+    }
+}