1 files changed, 27 insertions, 0 deletions
diff --git a/src/test/ui/dyn-star/dont-unsize-coerce-dyn-star.rs b/src/test/ui/dyn-star/dont-unsize-coerce-dyn-star.rs
new file mode 100644
index 000000000..c12b16f16
--- /dev/null
+++ b/src/test/ui/dyn-star/dont-unsize-coerce-dyn-star.rs
@@ -0,0 +1,27 @@
+// run-pass
+// check-run-results
+
+#![feature(dyn_star)]
+//~^ WARN the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes
+
+trait AddOne {
+    fn add1(&mut self) -> usize;
+}
+
+impl AddOne for usize {
+    fn add1(&mut self) -> usize {
+        *self += 1;
+        *self
+    }
+}
+
+fn add_one(i: &mut (dyn* AddOne + '_)) -> usize {
+    i.add1()
+}
+
+fn main() {
+    let mut x = 42usize as dyn* AddOne;
+
+    println!("{}", add_one(&mut x));
+    println!("{}", add_one(&mut x));
+}