From 5843858c015614c92515f317ce93796c885ca2cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Sun, 28 May 2023 15:47:44 +0200
Subject: [PATCH] Don't access self.mask with a single shard

---
 compiler/rustc_data_structures/src/sharded.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler/rustc_data_structures/src/sharded.rs b/compiler/rustc_data_structures/src/sharded.rs
index c16b9cbf8b7..9f5c97ae798 100644
--- a/compiler/rustc_data_structures/src/sharded.rs
+++ b/compiler/rustc_data_structures/src/sharded.rs
@@ -46,7 +46,7 @@ pub fn new(mut value: impl FnMut() -> T) -> Self {
     fn mask(&self) -> usize {
         #[cfg(parallel_compiler)]
         {
-            self.mask
+            if SHARDS == 1 { 0 } else { self.mask }
         }
         #[cfg(not(parallel_compiler))]
         {