1 files changed, 13 insertions, 0 deletions
diff --git a/src/test/ui/dyn-star/no-unsize-coerce-dyn-trait.rs b/src/test/ui/dyn-star/no-unsize-coerce-dyn-trait.rs
new file mode 100644
index 000000000..a4eb669e3
--- /dev/null
+++ b/src/test/ui/dyn-star/no-unsize-coerce-dyn-trait.rs
@@ -0,0 +1,13 @@
+#![feature(dyn_star, trait_upcasting)]
+//~^ WARN the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes
+
+trait A: B {}
+trait B {}
+impl A for usize {}
+impl B for usize {}
+
+fn main() {
+    let x: Box<dyn* A> = Box::new(1usize as dyn* A);
+    let y: Box<dyn* B> = x;
+    //~^ ERROR mismatched types
+}