Fix type-inference in sink::unfold() by specifying more of its types (r…

…ust-lang#2311)
exrook · Jan 12, 2021 · 21c467c · 21c467c
1 parent b13560b
commit 21c467c
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/futures-util/src/sink/unfold.rs b/futures-util/src/sink/unfold.rs
@@ -35,7 +35,11 @@ pin_project! {
 /// unfold.send(5).await?;
 /// # Ok::<(), futures::never::Never>(()) }).unwrap();
 /// ```
-pub fn unfold<T, F, R>(init: T, function: F) -> Unfold<T, F, R> {
+pub fn unfold<T, F, R, Item, E>(init: T, function: F) -> Unfold<T, F, R>
+where
+    F: FnMut(T, Item) -> R,
+    R: Future<Output = Result<T, E>>,
+{
     Unfold { function, state: UnfoldState::Value { value: init } }
 }