diff --git a/src/blocking/wait.rs b/src/blocking/wait.rs
index f1b27b5bf..3c903f8bf 100644
--- a/src/blocking/wait.rs
+++ b/src/blocking/wait.rs
@@ -70,7 +70,7 @@ fn enter() {
     // Check we aren't already in a runtime
     #[cfg(debug_assertions)]
     {
-        tokio::runtime::Builder::new_current_thread()
+        let _enter = tokio::runtime::Builder::new_current_thread()
             .build()
             .expect("build shell runtime")
             .enter();