diff --git a/Cargo.lock b/Cargo.lock
index ffc1f0dec1d9a..13d9a962e37a9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3420,7 +3420,6 @@ dependencies = [
  "lazy_static",
  "libc",
  "measureme",
- "once_cell",
  "parking_lot 0.10.2",
  "rustc-hash",
  "rustc-rayon",
diff --git a/compiler/rustc_data_structures/Cargo.toml b/compiler/rustc_data_structures/Cargo.toml
index f929d9911f91a..464f8c984dde8 100644
--- a/compiler/rustc_data_structures/Cargo.toml
+++ b/compiler/rustc_data_structures/Cargo.toml
@@ -13,7 +13,6 @@ indexmap = "1.5.1"
 tracing = "0.1"
 jobserver_crate = { version = "0.1.13", package = "jobserver" }
 lazy_static = "1"
-once_cell = { version = "1", features = ["parking_lot"] }
 rustc_serialize = { path = "../rustc_serialize" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_graphviz = { path = "../rustc_graphviz" }
diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs
index af4a7bd18813e..78b7e08ceedef 100644
--- a/compiler/rustc_data_structures/src/lib.rs
+++ b/compiler/rustc_data_structures/src/lib.rs
@@ -26,6 +26,7 @@
 #![feature(extend_one)]
 #![feature(const_panic)]
 #![feature(const_generics)]
+#![feature(once_cell)]
 #![allow(rustc::default_hash_types)]
 
 #[macro_use]
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index 53d831749ceb7..d22f3adfb016d 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -229,7 +229,7 @@ cfg_if! {
         pub use std::cell::RefMut as LockGuard;
         pub use std::cell::RefMut as MappedLockGuard;
 
-        pub use once_cell::unsync::OnceCell;
+        pub use std::lazy::OnceCell;
 
         use std::cell::RefCell as InnerRwLock;
         use std::cell::RefCell as InnerLock;
@@ -314,7 +314,7 @@ cfg_if! {
         pub use parking_lot::MutexGuard as LockGuard;
         pub use parking_lot::MappedMutexGuard as MappedLockGuard;
 
-        pub use once_cell::sync::OnceCell;
+        pub use std::lazy::SyncOnceCell as OnceCell;
 
         pub use std::sync::atomic::{AtomicBool, AtomicUsize, AtomicU32, AtomicU64};
 
diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index 09f5b22cc6381..0d8332a20aea4 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -6,6 +6,7 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![feature(nll)]
+#![feature(once_cell)]
 #![recursion_limit = "256"]
 
 #[macro_use]
diff --git a/compiler/rustc_interface/src/lib.rs b/compiler/rustc_interface/src/lib.rs
index fe40c615f79c9..88d2efe96d162 100644
--- a/compiler/rustc_interface/src/lib.rs
+++ b/compiler/rustc_interface/src/lib.rs
@@ -4,6 +4,7 @@
 #![feature(nll)]
 #![feature(generator_trait)]
 #![feature(generators)]
+#![feature(once_cell)]
 #![recursion_limit = "256"]
 
 mod callbacks;
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index 1b2dea8a378c3..a675aae5b17d4 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -38,6 +38,7 @@
 #![feature(exhaustive_patterns)]
 #![feature(extern_types)]
 #![feature(nll)]
+#![feature(once_cell)]
 #![feature(option_expect_none)]
 #![feature(or_patterns)]
 #![feature(min_specialization)]
diff --git a/compiler/rustc_session/src/lib.rs b/compiler/rustc_session/src/lib.rs
index c2ea141a06fe3..a808261798da7 100644
--- a/compiler/rustc_session/src/lib.rs
+++ b/compiler/rustc_session/src/lib.rs
@@ -1,4 +1,5 @@
 #![feature(crate_visibility_modifier)]
+#![feature(once_cell)]
 #![feature(or_patterns)]
 
 #[macro_use]