Replace once_cell with standard library OnceLock and LazyLock

Author: dtolnay

BUCK

@@ -73,7 +73,6 @@ rust_library(
     deps = [
         "//third-party:cc",
         "//third-party:codespan-reporting",
-        "//third-party:once_cell",
         "//third-party:proc-macro2",
         "//third-party:quote",
         "//third-party:scratch",

BUILD

@@ -69,7 +69,6 @@ rust_library(
     deps = [
         "@crates.io//:cc",
         "@crates.io//:codespan-reporting",
-        "@crates.io//:once_cell",
         "@crates.io//:proc-macro2",
         "@crates.io//:quote",
         "@crates.io//:scratch",

gen/build/Cargo.toml

@@ -21,7 +21,6 @@ experimental-async-fn = []
 [dependencies]
 cc = "1.0.83"
 codespan-reporting = "0.11.1"
-once_cell = "1.18"
 proc-macro2 = { version = "1.0.74", default-features = false, features = ["span-locations"] }
 quote = { version = "1.0.35", default-features = false }
 scratch = "1.0.5"

gen/build/src/cargo.rs

@@ -1,11 +1,11 @@
 use crate::gen::{CfgEvaluator, CfgResult};
-use once_cell::sync::OnceCell;
 use std::borrow::Borrow;
 use std::cmp::Ordering;
 use std::collections::{BTreeMap as Map, BTreeSet as Set};
 use std::env;
+use std::sync::OnceLock;
 
-static ENV: OnceCell<CargoEnv> = OnceCell::new();
+static ENV: OnceLock<CargoEnv> = OnceLock::new();
 
 struct CargoEnv {
     features: Set<Name>,

gen/build/src/cfg.rs

@@ -344,12 +344,11 @@ mod r#impl {
     use crate::intern::{intern, InternedString};
     use crate::syntax::map::UnorderedMap as Map;
     use crate::vec::{self, InternedVec as _};
-    use once_cell::sync::Lazy;
     use std::cell::RefCell;
     use std::fmt::{self, Debug};
     use std::marker::PhantomData;
     use std::ops::{Deref, DerefMut};
-    use std::sync::{PoisonError, RwLock};
+    use std::sync::{LazyLock, PoisonError, RwLock};
 
     struct CurrentCfg {
         include_prefix: InternedString,
@@ -378,7 +377,8 @@ mod r#impl {
         }
     }
 
-    static CURRENT: Lazy<RwLock<CurrentCfg>> = Lazy::new(|| RwLock::new(CurrentCfg::default()));
+    static CURRENT: LazyLock<RwLock<CurrentCfg>> =
+        LazyLock::new(|| RwLock::new(CurrentCfg::default()));
 
     thread_local! {
         // FIXME: If https://github.com/rust-lang/rust/issues/77425 is resolved,

gen/build/src/intern.rs

@@ -1,6 +1,5 @@
 use crate::syntax::set::UnorderedSet as Set;
-use once_cell::sync::OnceCell;
-use std::sync::{Mutex, PoisonError};
+use std::sync::{Mutex, OnceLock, PoisonError};
 
 #[derive(Copy, Clone, Default)]
 pub(crate) struct InternedString(&'static str);
@@ -12,7 +11,7 @@ impl InternedString {
 }
 
 pub(crate) fn intern(s: &str) -> InternedString {
-    static INTERN: OnceCell<Mutex<Set<&'static str>>> = OnceCell::new();
+    static INTERN: OnceLock<Mutex<Set<&'static str>>> = OnceLock::new();
 
     let mut set = INTERN
         .get_or_init(|| Mutex::new(Set::new()))