1 files changed, 44 insertions, 0 deletions
diff --git a/tests/ui/generator/iterator-count.rs b/tests/ui/generator/iterator-count.rs
new file mode 100644
index 000000000..90eefe02f
--- /dev/null
+++ b/tests/ui/generator/iterator-count.rs
@@ -0,0 +1,44 @@
+// run-pass
+
+#![feature(generators, generator_trait)]
+
+use std::marker::Unpin;
+use std::ops::{GeneratorState, Generator};
+use std::pin::Pin;
+
+struct W<T>(T);
+
+// This impl isn't safe in general, but the generator used in this test is movable
+// so it won't cause problems.
+impl<T: Generator<(), Return = ()> + Unpin> Iterator for W<T> {
+    type Item = T::Yield;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match Pin::new(&mut self.0).resume(()) {
+            GeneratorState::Complete(..) => None,
+            GeneratorState::Yielded(v) => Some(v),
+        }
+    }
+}
+
+fn test() -> impl Generator<(), Return=(), Yield=u8> + Unpin {
+    || {
+        for i in 1..6 {
+            yield i
+        }
+    }
+}
+
+fn main() {
+    let end = 11;
+
+    let closure_test = |start| {
+        move || {
+            for i in start..end {
+                yield i
+            }
+        }
+    };
+
+    assert!(W(test()).chain(W(closure_test(6))).eq(1..11));
+}