1 files changed, 91 insertions, 0 deletions
diff --git a/src/test/ui/try-trait/try-operator-custom.rs b/src/test/ui/try-trait/try-operator-custom.rs
new file mode 100644
index 000000000..45636a7fc
--- /dev/null
+++ b/src/test/ui/try-trait/try-operator-custom.rs
@@ -0,0 +1,91 @@
+// run-pass
+
+#![feature(control_flow_enum)]
+#![feature(try_trait_v2)]
+
+use std::ops::{ControlFlow, FromResidual, Try};
+
+enum MyResult<T, U> {
+    Awesome(T),
+    Terrible(U)
+}
+
+enum Never {}
+
+impl<U, V> Try for MyResult<U, V> {
+    type Output = U;
+    type Residual = MyResult<Never, V>;
+
+    fn from_output(u: U) -> MyResult<U, V> {
+        MyResult::Awesome(u)
+    }
+
+    fn branch(self) -> ControlFlow<Self::Residual, Self::Output> {
+        match self {
+            MyResult::Awesome(u) => ControlFlow::Continue(u),
+            MyResult::Terrible(e) => ControlFlow::Break(MyResult::Terrible(e)),
+        }
+    }
+}
+
+impl<U, V, W> FromResidual<MyResult<Never, V>> for MyResult<U, W> where V: Into<W> {
+    fn from_residual(x: MyResult<Never, V>) -> Self {
+        match x {
+            MyResult::Awesome(u) => match u {},
+            MyResult::Terrible(e) => MyResult::Terrible(e.into()),
+        }
+    }
+}
+
+type ResultResidual<E> = Result<std::convert::Infallible, E>;
+
+impl<U, V, W> FromResidual<ResultResidual<V>> for MyResult<U, W> where V: Into<W> {
+    fn from_residual(x: ResultResidual<V>) -> Self {
+        match x {
+            Ok(v) => match v {}
+            Err(e) => MyResult::Terrible(e.into()),
+        }
+    }
+}
+
+impl<U, V, W> FromResidual<MyResult<Never, V>> for Result<U, W> where V: Into<W> {
+    fn from_residual(x: MyResult<Never, V>) -> Self {
+        match x {
+            MyResult::Awesome(u) => match u {},
+            MyResult::Terrible(e) => Err(e.into()),
+        }
+    }
+}
+
+fn f(x: i32) -> Result<i32, String> {
+    if x == 0 {
+        Ok(42)
+    } else {
+        let y = g(x)?;
+        Ok(y)
+    }
+}
+
+fn g(x: i32) -> MyResult<i32, String> {
+    let _y = f(x - 1)?;
+    MyResult::Terrible("Hello".to_owned())
+}
+
+fn h() -> MyResult<i32, String> {
+    let a: Result<i32, &'static str> = Err("Hello");
+    let b = a?;
+    MyResult::Awesome(b)
+}
+
+fn i() -> MyResult<i32, String> {
+    let a: MyResult<i32, &'static str> = MyResult::Terrible("Hello");
+    let b = a?;
+    MyResult::Awesome(b)
+}
+
+fn main() {
+    assert!(f(0) == Ok(42));
+    assert!(f(10) == Err("Hello".to_owned()));
+    let _ = h();
+    let _ = i();
+}