From 68500ffacb4d28586a9c17799ab73e41aa2cfe94 Mon Sep 17 00:00:00 2001
From: marmeladema <xademax@gmail.com>
Date: Sat, 29 Aug 2020 19:16:49 +0100
Subject: [PATCH] datastructures: replace `once_cell` crate with an impl from
 std

---
 Cargo.lock                                 | 1 -
 compiler/rustc_data_structures/Cargo.toml  | 1 -
 compiler/rustc_data_structures/src/lib.rs  | 1 +
 compiler/rustc_data_structures/src/sync.rs | 4 ++--
 compiler/rustc_driver/src/lib.rs           | 1 +
 compiler/rustc_interface/src/lib.rs        | 1 +
 compiler/rustc_middle/src/lib.rs           | 1 +
 compiler/rustc_session/src/lib.rs          | 1 +
 8 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index ffc1f0dec1d..13d9a962e37 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 f929d9911f9..464f8c984dd 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 af4a7bd1881..78b7e08ceed 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 53d831749ce..d22f3adfb01 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 09f5b22cc63..0d8332a20ae 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 fe40c615f79..88d2efe96d1 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 1b2dea8a378..a675aae5b17 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 c2ea141a06f..a808261798d 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]