Rollup merge of #137922 - Zalathar:sharded, r=SparrowLii

A few cleanups after the removal of `cfg(not(parallel))`

I noticed a few small things that are no longer needed after the removal of `cfg(not(parallel))` in #132282.

One of the later changes adjusts several imports, so viewing the changes individually is recommended.

r? SparrowLii (or reroll)

2 files changed, 1 insertions, 4 deletions

diff --git a/src/doc/rustc-dev-guide/src/parallel-rustc.md b/src/doc/rustc-dev-guide/src/parallel-rustc.md
index c5b70706a81..690fb19c9f5 100644
--- a/src/doc/rustc-dev-guide/src/parallel-rustc.md
+++ b/src/doc/rustc-dev-guide/src/parallel-rustc.md
@@ -46,10 +46,8 @@ are implemented differently depending on whether `parallel-compiler` is true.
 
 | data structure                   | parallel                                            | non-parallel |
 | -------------------------------- | --------------------------------------------------- | ------------ |
-| OnceCell                         | std::sync::OnceLock                                 | std::cell::OnceCell |
 | Lock\<T> | (parking_lot::Mutex\<T>) | (std::cell::RefCell) |
 | RwLock\<T> | (parking_lot::RwLock\<T>) | (std::cell::RefCell) |
-| MTRef<'a, T> | &'a T | &'a mut T |
 | MTLock\<T> | (Lock\<T>) | (T) |
 | ReadGuard | parking_lot::RwLockReadGuard | std::cell::Ref |
 | MappedReadGuard | parking_lot::MappedRwLockReadGuard | std::cell::Ref |
diff --git a/src/tools/clippy/clippy_utils/src/macros.rs b/src/tools/clippy/clippy_utils/src/macros.rs
index 3ce2cdfebe9..1a457bc7f21 100644
--- a/src/tools/clippy/clippy_utils/src/macros.rs
+++ b/src/tools/clippy/clippy_utils/src/macros.rs
@@ -1,6 +1,6 @@
 #![allow(clippy::similar_names)] // `expr` and `expn`
 
-use std::sync::Arc;
+use std::sync::{Arc, OnceLock};
 
 use crate::get_unique_attr;
 use crate::visitors::{Descend, for_each_expr_without_closures};
@@ -8,7 +8,6 @@ use crate::visitors::{Descend, for_each_expr_without_closures};
 use arrayvec::ArrayVec;
 use rustc_ast::{FormatArgs, FormatArgument, FormatPlaceholder};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::sync::OnceLock;
 use rustc_hir::{self as hir, Expr, ExprKind, HirId, Node, QPath};
 use rustc_lint::{LateContext, LintContext};
 use rustc_span::def_id::DefId;