1 files changed, 24 insertions, 0 deletions
diff --git a/tests/ui/try-trait/try-as-monad.rs b/tests/ui/try-trait/try-as-monad.rs
new file mode 100644
index 00000000000..cf09838b304
--- /dev/null
+++ b/tests/ui/try-trait/try-as-monad.rs
@@ -0,0 +1,24 @@
+// run-pass
+
+#![feature(try_trait_v2)]
+
+use std::ops::Try;
+
+fn monad_unit<T: Try>(x: <T as Try>::Output) -> T {
+    T::from_output(x)
+}
+
+fn monad_bind<T1: Try<Residual = R>, T2: Try<Residual = R>, R>(
+    mx: T1,
+    f: impl FnOnce(<T1 as Try>::Output) -> T2)
+-> T2 {
+    let x = mx?;
+    f(x)
+}
+
+fn main() {
+    let mx: Option<i32> = monad_unit(1);
+    let my = monad_bind(mx, |x| Some(x + 1));
+    let mz = monad_bind(my, |x| Some(-x));
+    assert_eq!(mz, Some(-2));
+}