1 files changed, 54 insertions, 0 deletions
diff --git a/src/test/ui/borrowck/borrowck-closures-unique.rs b/src/test/ui/borrowck/borrowck-closures-unique.rs
new file mode 100644
index 000000000..67f91dfa8
--- /dev/null
+++ b/src/test/ui/borrowck/borrowck-closures-unique.rs
@@ -0,0 +1,54 @@
+// Tests that a closure which requires mutable access to the referent
+// of an `&mut` requires a "unique" borrow -- that is, the variable to
+// be borrowed (here, `x`) will not be borrowed *mutably*, but
+//  may be *immutable*, but we cannot allow
+// multiple borrows.
+
+
+
+fn get(x: &isize) -> isize {
+    *x
+}
+
+fn set(x: &mut isize) -> isize {
+    *x
+}
+
+fn a(x: &mut isize) {
+    let c1 = || get(x);
+    let c2 = || get(x);
+    c1();
+    c2();
+}
+
+fn b(x: &mut isize) {
+    let c1 = || get(x);
+    let c2 = || set(x); //~ ERROR closure requires unique access to `x`
+    c1;
+}
+
+fn c(x: &mut isize) {
+    let c1 = || get(x);
+    let c2 = || { get(x); set(x); }; //~ ERROR closure requires unique access to `x`
+    c1;
+}
+
+fn d(x: &mut isize) {
+    let c1 = || set(x);
+    let c2 = || set(x); //~ ERROR two closures require unique access to `x` at the same time
+    c1;
+}
+
+fn e(x: &'static mut isize) {
+    let c1 = |y: &'static mut isize| x = y;
+    //~^ ERROR cannot assign to `x`, as it is not declared as mutable
+    c1;
+}
+
+fn f(x: &'static mut isize) {
+    let c1 = || x = panic!(); // OK assignment is unreachable.
+    c1;
+}
+
+fn main() {
+}