1 files changed, 95 insertions, 0 deletions
diff --git a/src/test/ui/traits/trait-upcasting/lifetime.rs b/src/test/ui/traits/trait-upcasting/lifetime.rs
new file mode 100644
index 000000000..f029a6f08
--- /dev/null
+++ b/src/test/ui/traits/trait-upcasting/lifetime.rs
@@ -0,0 +1,95 @@
+// run-pass
+
+#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
+
+trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
+    fn a(&self) -> i32 {
+        10
+    }
+
+    fn z(&self) -> i32 {
+        11
+    }
+
+    fn y(&self) -> i32 {
+        12
+    }
+}
+
+trait Bar: Foo {
+    fn b(&self) -> i32 {
+        20
+    }
+
+    fn w(&self) -> i32 {
+        21
+    }
+}
+
+trait Baz: Bar {
+    fn c(&self) -> i32 {
+        30
+    }
+}
+
+impl Foo for i32 {
+    fn a(&self) -> i32 {
+        100
+    }
+}
+
+impl Bar for i32 {
+    fn b(&self) -> i32 {
+        200
+    }
+}
+
+impl Baz for i32 {
+    fn c(&self) -> i32 {
+        300
+    }
+}
+
+// Note: upcast lifetime means a shorter lifetime.
+fn upcast_baz<'a: 'b, 'b, T>(v: Box<dyn Baz + 'a>, _l: &'b T) -> Box<dyn Baz + 'b> {
+    v
+}
+fn upcast_bar<'a: 'b, 'b, T>(v: Box<dyn Bar + 'a>, _l: &'b T) -> Box<dyn Bar + 'b> {
+    v
+}
+fn upcast_foo<'a: 'b, 'b, T>(v: Box<dyn Foo + 'a>, _l: &'b T) -> Box<dyn Foo + 'b> {
+    v
+}
+
+fn main() {
+    let v = Box::new(1);
+    let l = &(); // dummy lifetime (shorter than `baz`)
+
+    let baz: Box<dyn Baz> = v.clone();
+    let u = upcast_baz(baz, &l);
+    assert_eq!(*u, 1);
+    assert_eq!(u.a(), 100);
+    assert_eq!(u.b(), 200);
+    assert_eq!(u.c(), 300);
+
+    let baz: Box<dyn Baz> = v.clone();
+    let bar: Box<dyn Bar> = baz;
+    let u = upcast_bar(bar, &l);
+    assert_eq!(*u, 1);
+    assert_eq!(u.a(), 100);
+    assert_eq!(u.b(), 200);
+
+    let baz: Box<dyn Baz> = v.clone();
+    let foo: Box<dyn Foo> = baz;
+    let u = upcast_foo(foo, &l);
+    assert_eq!(*u, 1);
+    assert_eq!(u.a(), 100);
+
+    let baz: Box<dyn Baz> = v.clone();
+    let bar: Box<dyn Bar> = baz;
+    let foo: Box<dyn Foo> = bar;
+    let u = upcast_foo(foo, &l);
+    assert_eq!(*u, 1);
+    assert_eq!(u.a(), 100);
+}