2 files changed, 38 insertions, 45 deletions

diff --git a/compiler/rustc_data_structures/src/sharded.rs b/compiler/rustc_data_structures/src/sharded.rs
index 5a53f8af5f8..e6be9c256f0 100644
--- a/compiler/rustc_data_structures/src/sharded.rs
+++ b/compiler/rustc_data_structures/src/sharded.rs
@@ -43,10 +43,10 @@ impl<T> Sharded<T> {
 
     /// The shard is selected by hashing `val` with `FxHasher`.
     #[inline]
-    pub fn get_shard_by_value<K: Hash + ?Sized>(&self, _val: &K) -> &Lock<T> {
+    pub fn get_shard_by_value<K: Hash + ?Sized>(&self, val: &K) -> &Lock<T> {
         match self {
             Self::Single(single) => single,
-            Self::Shards(..) => self.get_shard_by_hash(make_hash(_val)),
+            Self::Shards(..) => self.get_shard_by_hash(make_hash(val)),
         }
     }
 
@@ -56,12 +56,12 @@ impl<T> Sharded<T> {
     }
 
     #[inline]
-    pub fn get_shard_by_index(&self, _i: usize) -> &Lock<T> {
+    pub fn get_shard_by_index(&self, i: usize) -> &Lock<T> {
         match self {
             Self::Single(single) => single,
             Self::Shards(shards) => {
                 // SAFETY: The index gets ANDed with the shard mask, ensuring it is always inbounds.
-                unsafe { &shards.get_unchecked(_i & (SHARDS - 1)).0 }
+                unsafe { &shards.get_unchecked(i & (SHARDS - 1)).0 }
             }
         }
     }
@@ -69,7 +69,7 @@ impl<T> Sharded<T> {
     /// The shard is selected by hashing `val` with `FxHasher`.
     #[inline]
     #[track_caller]
-    pub fn lock_shard_by_value<K: Hash + ?Sized>(&self, _val: &K) -> LockGuard<'_, T> {
+    pub fn lock_shard_by_value<K: Hash + ?Sized>(&self, val: &K) -> LockGuard<'_, T> {
         match self {
             Self::Single(single) => {
                 // Synchronization is disabled so use the `lock_assume_no_sync` method optimized
@@ -79,7 +79,7 @@ impl<T> Sharded<T> {
                 // `might_be_dyn_thread_safe` was also false.
                 unsafe { single.lock_assume(Mode::NoSync) }
             }
-            Self::Shards(..) => self.lock_shard_by_hash(make_hash(_val)),
+            Self::Shards(..) => self.lock_shard_by_hash(make_hash(val)),
         }
     }
 
@@ -91,7 +91,7 @@ impl<T> Sharded<T> {
 
     #[inline]
     #[track_caller]
-    pub fn lock_shard_by_index(&self, _i: usize) -> LockGuard<'_, T> {
+    pub fn lock_shard_by_index(&self, i: usize) -> LockGuard<'_, T> {
         match self {
             Self::Single(single) => {
                 // Synchronization is disabled so use the `lock_assume_no_sync` method optimized
@@ -109,7 +109,7 @@ impl<T> Sharded<T> {
                 // always inbounds.
                 // SAFETY (lock_assume_sync): We know `is_dyn_thread_safe` was true when creating
                 // the lock thus `might_be_dyn_thread_safe` was also true.
-                unsafe { shards.get_unchecked(_i & (SHARDS - 1)).0.lock_assume(Mode::Sync) }
+                unsafe { shards.get_unchecked(i & (SHARDS - 1)).0.lock_assume(Mode::Sync) }
             }
         }
     }
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index 37b54fe38ff..a1cc75c4985 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -18,42 +18,54 @@
 //!
 //! | Type                    | Serial version      | Parallel version                |
 //! | ----------------------- | ------------------- | ------------------------------- |
-//! | `LRef<'a, T>` [^2]      | `&'a mut T`         | `&'a T`                         |
-//! |                         |                     |                                 |
 //! | `Lock<T>`               | `RefCell<T>`        | `RefCell<T>` or                 |
 //! |                         |                     | `parking_lot::Mutex<T>`         |
 //! | `RwLock<T>`             | `RefCell<T>`        | `parking_lot::RwLock<T>`        |
 //! | `MTLock<T>`        [^1] | `T`                 | `Lock<T>`                       |
-//! | `MTLockRef<'a, T>` [^2] | `&'a mut MTLock<T>` | `&'a MTLock<T>`                 |
 //! |                         |                     |                                 |
 //! | `ParallelIterator`      | `Iterator`          | `rayon::iter::ParallelIterator` |
 //!
 //! [^1]: `MTLock` is similar to `Lock`, but the serial version avoids the cost
 //! of a `RefCell`. This is appropriate when interior mutability is not
 //! required.
-//!
-//! [^2]: `MTRef`, `MTLockRef` are type aliases.
 
 use std::collections::HashMap;
 use std::hash::{BuildHasher, Hash};
 
-pub use crate::marker::*;
+pub use parking_lot::{
+    MappedRwLockReadGuard as MappedReadGuard, MappedRwLockWriteGuard as MappedWriteGuard,
+    RwLockReadGuard as ReadGuard, RwLockWriteGuard as WriteGuard,
+};
 
-mod lock;
+pub use self::atomic::AtomicU64;
+pub use self::freeze::{FreezeLock, FreezeReadGuard, FreezeWriteGuard};
 #[doc(no_inline)]
-pub use lock::{Lock, LockGuard, Mode};
-
-mod worker_local;
-pub use worker_local::{Registry, WorkerLocal};
+pub use self::lock::{Lock, LockGuard, Mode};
+pub use self::mode::{is_dyn_thread_safe, set_dyn_thread_safe_mode};
+pub use self::parallel::{
+    join, par_for_each_in, par_map, parallel_guard, scope, try_par_for_each_in,
+};
+pub use self::vec::{AppendOnlyIndexVec, AppendOnlyVec};
+pub use self::worker_local::{Registry, WorkerLocal};
+pub use crate::marker::*;
 
+mod freeze;
+mod lock;
 mod parallel;
-pub use parallel::{join, par_for_each_in, par_map, parallel_guard, scope, try_par_for_each_in};
-pub use vec::{AppendOnlyIndexVec, AppendOnlyVec};
-
 mod vec;
+mod worker_local;
 
-mod freeze;
-pub use freeze::{FreezeLock, FreezeReadGuard, FreezeWriteGuard};
+/// Keep the conditional imports together in a submodule, so that import-sorting
+/// doesn't split them up.
+mod atomic {
+    // Most hosts can just use a regular AtomicU64.
+    #[cfg(target_has_atomic = "64")]
+    pub use std::sync::atomic::AtomicU64;
+
+    // Some 32-bit hosts don't have AtomicU64, so use a fallback.
+    #[cfg(not(target_has_atomic = "64"))]
+    pub use portable_atomic::AtomicU64;
+}
 
 mod mode {
     use std::sync::atomic::{AtomicU8, Ordering};
@@ -97,21 +109,6 @@ mod mode {
 
 // FIXME(parallel_compiler): Get rid of these aliases across the compiler.
 
-pub use std::sync::OnceLock;
-// Use portable AtomicU64 for targets without native 64-bit atomics
-#[cfg(target_has_atomic = "64")]
-pub use std::sync::atomic::AtomicU64;
-
-pub use mode::{is_dyn_thread_safe, set_dyn_thread_safe_mode};
-pub use parking_lot::{
-    MappedRwLockReadGuard as MappedReadGuard, MappedRwLockWriteGuard as MappedWriteGuard,
-    RwLockReadGuard as ReadGuard, RwLockWriteGuard as WriteGuard,
-};
-#[cfg(not(target_has_atomic = "64"))]
-pub use portable_atomic::AtomicU64;
-
-pub type LRef<'a, T> = &'a T;
-
 #[derive(Debug, Default)]
 pub struct MTLock<T>(Lock<T>);
 
@@ -142,14 +139,10 @@ impl<T> MTLock<T> {
     }
 }
 
-use parking_lot::RwLock as InnerRwLock;
-
 /// This makes locks panic if they are already held.
 /// It is only useful when you are running in a single thread
 const ERROR_CHECKING: bool = false;
 
-pub type MTLockRef<'a, T> = LRef<'a, MTLock<T>>;
-
 #[derive(Default)]
 #[repr(align(64))]
 pub struct CacheAligned<T>(pub T);
@@ -167,12 +160,12 @@ impl<K: Eq + Hash, V: Eq, S: BuildHasher> HashMapExt<K, V> for HashMap<K, V, S>
 }
 
 #[derive(Debug, Default)]
-pub struct RwLock<T>(InnerRwLock<T>);
+pub struct RwLock<T>(parking_lot::RwLock<T>);
 
 impl<T> RwLock<T> {
     #[inline(always)]
     pub fn new(inner: T) -> Self {
-        RwLock(InnerRwLock::new(inner))
+        RwLock(parking_lot::RwLock::new(inner))
     }
 
     #[inline(always)]