i did an Undefined Behaviour, thanks miri

messing_with_async/src/wake.rs

@@ -31,7 +31,7 @@ fn vtable<W: ArcWake>() -> &'static RawWakerVTable {
         },
         |ptr| unsafe {
             // will get dropped, decrementing strong count
-            Arc::from_raw(ptr);
+            Arc::from_raw(ptr as *const W);
         }
     )
 }