From 45b22efe06630703e20de19c589299e6a592469e Mon Sep 17 00:00:00 2001
From: Martin Nordholts <martin.nordholts@codetale.se>
Date: Wed, 18 Mar 2026 21:29:45 +0100
Subject: [PATCH] tests: Activate must_not_suspend test for MutexGuard dropped
 before await

The test pass in `nightly-2023-09-24` but fail in `nightly-2023-09-23`:

    $ rustc +nightly-2023-09-23 --edition 2018 tests/ui/lint/must_not_suspend/mutex-guard-dropped-before-await.rs
    error: `MutexGuard` held across a suspend point, but should not be
      --> tests/ui/lint/must_not_suspend/mutex-guard-dropped-before-await.rs:13:9
       |
    13 |     let lock = foo.lock().unwrap();
       |         ^^^^
    ...
    18 |     bar().await;
       |           ----- the value is held across this suspend point
       |
---
 src/tools/tidy/src/issues.txt                               | 1 -
 .../{issue-89562.rs => mutex-guard-dropped-before-await.rs} | 6 +++++-
 2 files changed, 5 insertions(+), 2 deletions(-)
 rename tests/ui/lint/must_not_suspend/{issue-89562.rs => mutex-guard-dropped-before-await.rs} (67%)

diff --git a/src/tools/tidy/src/issues.txt b/src/tools/tidy/src/issues.txt
index 668a8abf1d8bb..a9dc449afa835 100644
--- a/src/tools/tidy/src/issues.txt
+++ b/src/tools/tidy/src/issues.txt
@@ -1476,7 +1476,6 @@ ui/lint/issue-97094.rs
 ui/lint/issue-99387.rs
 ui/lint/let_underscore/issue-119696-err-on-fn.rs
 ui/lint/let_underscore/issue-119697-extra-let.rs
-ui/lint/must_not_suspend/issue-89562.rs
 ui/lint/unused/issue-103320-must-use-ops.rs
 ui/lint/unused/issue-104397.rs
 ui/lint/unused/issue-105061-array-lint.rs
diff --git a/tests/ui/lint/must_not_suspend/issue-89562.rs b/tests/ui/lint/must_not_suspend/mutex-guard-dropped-before-await.rs
similarity index 67%
rename from tests/ui/lint/must_not_suspend/issue-89562.rs
rename to tests/ui/lint/must_not_suspend/mutex-guard-dropped-before-await.rs
index 99a548130720f..d1c48c3c51457 100644
--- a/tests/ui/lint/must_not_suspend/issue-89562.rs
+++ b/tests/ui/lint/must_not_suspend/mutex-guard-dropped-before-await.rs
@@ -1,9 +1,13 @@
+//! Regression test for <https://github.com/rust-lang/rust/issues/89562>
+
 //@ edition:2018
 //@ run-pass
 
+#![feature(must_not_suspend)]
+#![deny(must_not_suspend)]
+
 use std::sync::Mutex;
 
-// Copied from the issue. Allow-by-default for now, so run-pass
 pub async fn foo() {
     let foo = Mutex::new(1);
     let lock = foo.lock().unwrap();