1 files changed, 35 insertions, 0 deletions
diff --git a/src/test/ui/generator/generator-yielding-or-returning-itself.rs b/src/test/ui/generator/generator-yielding-or-returning-itself.rs
new file mode 100644
index 000000000..30788e3c1
--- /dev/null
+++ b/src/test/ui/generator/generator-yielding-or-returning-itself.rs
@@ -0,0 +1,35 @@
+#![feature(generator_trait)]
+#![feature(generators)]
+
+// Test that we cannot create a generator that returns a value of its
+// own type.
+
+use std::ops::Generator;
+
+pub fn want_cyclic_generator_return<T>(_: T)
+    where T: Generator<Yield = (), Return = T>
+{
+}
+
+fn supply_cyclic_generator_return() {
+    want_cyclic_generator_return(|| {
+        //~^ ERROR type mismatch
+        if false { yield None.unwrap(); }
+        None.unwrap()
+    })
+}
+
+pub fn want_cyclic_generator_yield<T>(_: T)
+    where T: Generator<Yield = T, Return = ()>
+{
+}
+
+fn supply_cyclic_generator_yield() {
+    want_cyclic_generator_yield(|| {
+        //~^ ERROR type mismatch
+        if false { yield None.unwrap(); }
+        None.unwrap()
+    })
+}
+
+fn main() { }