first fixes

Author: dignifiedquire

Cargo.toml

@@ -86,7 +86,7 @@ blocking = { version = "0.5.2", optional = true }
 futures-lite = { version = "0.1.8", optional = true }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
-futures-timer = { version = "3.0.2", optional = true, features = ["wasm-bindgen"] }
+futures-timer = { version = "3.0.2", features = ["wasm-bindgen"] }
 wasm-bindgen-futures = { version = "0.4.10", optional = true }
 futures-channel = { version = "0.3.4", optional = true }
 

src/task/join_handle.rs

@@ -78,7 +78,17 @@ impl<T> Drop for JoinHandle<T> {
 impl<T> Future for JoinHandle<T> {
     type Output = T;
 
+    #[cfg(not(target_os = "unknown"))]
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         Pin::new(&mut self.handle.as_mut().unwrap()).poll(cx)
     }
+
+    #[cfg(target_arch = "wasm32")]
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        match Pin::new(&mut self.handle.as_mut().unwrap()).poll(cx) {
+            Poll::Ready(Ok(t)) => Poll::Ready(t),
+            Poll::Ready(Err(_)) => unreachable!("channel must not be canceled"),
+            Poll::Pending => Poll::Pending,
+        }
+    }
 }