1 files changed, 41 insertions, 0 deletions
diff --git a/tests/ui/dst/dst-bad-assign.rs b/tests/ui/dst/dst-bad-assign.rs
new file mode 100644
index 00000000000..496e01ae005
--- /dev/null
+++ b/tests/ui/dst/dst-bad-assign.rs
@@ -0,0 +1,41 @@
+// Forbid assignment into a dynamically sized type.
+
+struct Fat<T: ?Sized> {
+    f1: isize,
+    f2: &'static str,
+    ptr: T
+}
+
+#[derive(PartialEq,Eq)]
+struct Bar;
+
+#[derive(PartialEq,Eq)]
+struct Bar1 {
+    f: isize
+}
+
+trait ToBar {
+    fn to_bar(&self) -> Bar;
+    fn to_val(&self) -> isize;
+}
+
+impl ToBar for Bar1 {
+    fn to_bar(&self) -> Bar {
+        Bar
+    }
+    fn to_val(&self) -> isize {
+        self.f
+    }
+}
+
+pub fn main() {
+    // Assignment.
+    let f5: &mut Fat<dyn ToBar> = &mut Fat { f1: 5, f2: "some str", ptr: Bar1 {f :42} };
+    let z: Box<dyn ToBar> = Box::new(Bar1 {f: 36});
+    f5.ptr = Bar1 {f: 36};
+    //~^ ERROR mismatched types
+    //~| expected trait object `dyn ToBar`, found struct `Bar1`
+    //~| expected trait object `dyn ToBar`
+    //~| found struct `Bar1`
+    //~| ERROR the size for values of type
+}