1 files changed, 28 insertions, 0 deletions
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-counter-not-moved.rs b/src/test/ui/unboxed-closures/unboxed-closures-counter-not-moved.rs
new file mode 100644
index 000000000..390386e57
--- /dev/null
+++ b/src/test/ui/unboxed-closures/unboxed-closures-counter-not-moved.rs
@@ -0,0 +1,28 @@
+// run-pass
+// Test that we mutate a counter on the stack only when we expect to.
+
+fn call<F>(f: F) where F : FnOnce() {
+    f();
+}
+
+fn main() {
+    let y = vec![format!("Hello"), format!("World")];
+    let mut counter = 22_u32;
+
+    call(|| {
+        // Move `y`, but do not move `counter`, even though it is read
+        // by value (note that it is also mutated).
+        for item in y { //~ WARN unused variable: `item`
+            let v = counter;
+            counter += v;
+        }
+    });
+    assert_eq!(counter, 88);
+
+    call(move || {
+        // this mutates a moved copy, and hence doesn't affect original
+        counter += 1; //~  WARN value assigned to `counter` is never read
+                      //~| WARN unused variable: `counter`
+    });
+    assert_eq!(counter, 88);
+}