diff --git a/src/lib.rs b/src/lib.rs
index ca13164..b3372ef 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -21,8 +21,8 @@ static VTABLE: RawWakerVTable = RawWakerVTable::new(
 );
 
 /// Run a `Future`.
-pub fn run<F: std::future::Future>(mut f: F) -> F::Output {
-    let mut f = unsafe { std::pin::Pin::new_unchecked(&mut f) };
+pub unsafe fn run<F: std::future::Future>(mut f: F) -> F::Output {
+    let mut f = std::pin::Pin::new_unchecked(&mut f);
     let park = Arc::new(Park::default());
     let sender = Arc::into_raw(park.clone());
     let raw_waker = RawWaker::new(sender as *const _, &VTABLE);
diff --git a/tests/smoke.rs b/tests/smoke.rs
index 353f438..5d90183 100644
--- a/tests/smoke.rs
+++ b/tests/smoke.rs
@@ -11,18 +11,20 @@ use std::{
 #[test]
 fn smoke() {
     let s = S(Arc::new(AtomicBool::new(false)));
-    extreme::run(async {});
-    extreme::run(async {
-        async {
-            s.await
-        }.await
-    });
-    extreme::run(async {
-        async {
+    unsafe {
+        extreme::run(async {});
+        extreme::run(async {
             async {
+                s.await
             }.await
-        }.await
-    });
+        });
+        extreme::run(async {
+            async {
+                async {
+                }.await
+            }.await
+        });
+    }
 }
 
 struct S(Arc<AtomicBool>);