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+### What it does
+Checks for `let _ = sync_lock`.
+This supports `mutex` and `rwlock` in `std::sync` and `parking_lot`.
+
+### Why is this bad?
+This statement immediately drops the lock instead of
+extending its lifetime to the end of the scope, which is often not intended.
+To extend lock lifetime to the end of the scope, use an underscore-prefixed
+name instead (i.e. _lock). If you want to explicitly drop the lock,
+`std::mem::drop` conveys your intention better and is less error-prone.
+
+### Example
+```
+let _ = mutex.lock();
+```
+
+Use instead:
+```
+let _lock = mutex.lock();
+```
+\ No newline at end of file