1 files changed, 14 insertions, 0 deletions
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-mutated-upvar-from-fn-closure.rs b/src/test/ui/unboxed-closures/unboxed-closures-mutated-upvar-from-fn-closure.rs
new file mode 100644
index 000000000..174ad245d
--- /dev/null
+++ b/src/test/ui/unboxed-closures/unboxed-closures-mutated-upvar-from-fn-closure.rs
@@ -0,0 +1,14 @@
+// Test that a by-ref `FnMut` closure gets an error when it tries to
+// mutate a value.
+
+fn call<F>(f: F) where F : Fn() {
+    f();
+}
+
+fn main() {
+    let mut counter = 0;
+    call(|| {
+        counter += 1;
+        //~^ ERROR cannot assign to `counter`
+    });
+}