diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index 8defcd39ecd..5fe1e8f8c4f 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -41,6 +41,7 @@
//! [^2] `MTLockRef` is a typedef.
pub use crate::marker::*;
+use parking_lot::Mutex;
use std::any::Any;
use std::collections::HashMap;
use std::hash::{BuildHasher, Hash};
@@ -110,13 +111,13 @@ pub use mode::{is_dyn_thread_safe, set_dyn_thread_safe_mode};
/// continuing with unwinding. It's also used for the non-parallel code to ensure error message
/// output match the parallel compiler for testing purposes.
pub struct ParallelGuard {
- panic: Lock