1 files changed, 15 insertions, 0 deletions
diff --git a/tests/ui/cannot-mutate-captured-non-mut-var.rs b/tests/ui/cannot-mutate-captured-non-mut-var.rs
new file mode 100644
index 00000000000..952dab25bf9
--- /dev/null
+++ b/tests/ui/cannot-mutate-captured-non-mut-var.rs
@@ -0,0 +1,15 @@
+#![feature(unboxed_closures, tuple_trait)]
+
+use std::io::Read;
+
+fn to_fn_once<A:std::marker::Tuple,F:FnOnce<A>>(f: F) -> F { f }
+
+fn main() {
+    let x = 1;
+    to_fn_once(move|| { x = 2; });
+    //~^ ERROR: cannot assign to `x`, as it is not declared as mutable
+
+    let s = std::io::stdin();
+    to_fn_once(move|| { s.read_to_end(&mut Vec::new()); });
+    //~^ ERROR: cannot borrow `s` as mutable, as it is not declared as mutable
+}