Implement existential types

1 files changed, 22 insertions, 0 deletions

diff --git a/src/test/ui/closure-immutable-outer-variable.rs b/src/test/ui/closure-immutable-outer-variable.rs
new file mode 100644
index 00000000000..e162678460c
--- /dev/null
+++ b/src/test/ui/closure-immutable-outer-variable.rs
@@ -0,0 +1,22 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// run-rustfix
+
+// Point at the captured immutable outer variable
+
+fn foo(mut f: Box<FnMut()>) {
+    f();
+}
+
+fn main() {
+    let y = true;
+    foo(Box::new(move || y = false) as Box<_>); //~ ERROR cannot assign to captured outer variable
+}