Remove unnecessary rustc_const_stable attributes.

rust-lang · JohnTitor · Oct 3, 2020 · Oct 8, 2020 · Oct 10, 2020 · Oct 11, 2020
commit e55d27fbcefffbddb85f28cf4eb913674f2188c6
diff --git a/library/std/src/sys/unsupported/mutex.rs b/library/std/src/sys/unsupported/mutex.rs
@@ -10,7 +10,6 @@ unsafe impl Send for Mutex {}
 unsafe impl Sync for Mutex {} // no threads on this platform
 
 impl Mutex {
-    #[rustc_const_stable(feature = "const_sys_mutex_new", since = "1.0.0")]
     pub const fn new() -> Mutex {
         Mutex { locked: UnsafeCell::new(false) }
     }

diff --git a/library/std/src/sys_common/mutex.rs b/library/std/src/sys_common/mutex.rs
@@ -21,7 +21,6 @@ impl StaticMutex {
     /// first used with any of the functions below.
     /// Also, the behavior is undefined if this mutex is ever used reentrantly,
     /// i.e., `lock` is called by the thread currently holding the lock.
-    #[rustc_const_stable(feature = "const_sys_mutex_new", since = "1.0.0")]
     pub const fn new() -> Self {
         Self(imp::Mutex::new())
     }