1 files changed, 39 insertions, 0 deletions
diff --git a/src/test/ui/self/object-safety-sized-self-return-Self.rs b/src/test/ui/self/object-safety-sized-self-return-Self.rs
new file mode 100644
index 000000000..222c75439
--- /dev/null
+++ b/src/test/ui/self/object-safety-sized-self-return-Self.rs
@@ -0,0 +1,39 @@
+// run-pass
+// Check that a trait is still object-safe (and usable) if it has
+// methods that return `Self` so long as they require `Self : Sized`.
+
+
+trait Counter {
+    fn new() -> Self where Self : Sized;
+    fn tick(&mut self) -> u32;
+}
+
+struct CCounter {
+    c: u32
+}
+
+impl Counter for CCounter {
+    fn new() -> CCounter { CCounter { c: 0 } }
+    fn tick(&mut self) -> u32 { self.c += 1; self.c }
+}
+
+fn preticked<C:Counter>() -> C {
+    let mut c: C = Counter::new();
+    tick(&mut c);
+    c
+}
+
+fn tick(c: &mut dyn Counter) {
+    tick_generic(c);
+}
+
+fn tick_generic<C:?Sized+Counter>(c: &mut C) {
+    c.tick();
+    c.tick();
+}
+
+fn main() {
+    let mut c = preticked::<CCounter>();
+    tick(&mut c);
+    assert_eq!(c.tick(), 5);
+}