Move array cycle test

library/core/tests/array.rs

@@ -330,3 +330,32 @@ fn array_map_drop_safety() {
     assert_eq!(DROPPED.load(Ordering::SeqCst), num_to_create);
     panic!("test succeeded")
 }
+
+#[test]
+fn cell_allows_array_cycle() {
+    use core::cell::Cell;
+
+    #[derive(Debug)]
+    struct B<'a> {
+        a: [Cell<Option<&'a B<'a>>>; 2],
+    }
+
+    impl<'a> B<'a> {
+        fn new() -> B<'a> {
+            B { a: [Cell::new(None), Cell::new(None)] }
+        }
+    }
+
+    let b1 = B::new();
+    let b2 = B::new();
+    let b3 = B::new();
+
+    b1.a[0].set(Some(&b2));
+    b1.a[1].set(Some(&b3));
+
+    b2.a[0].set(Some(&b2));
+    b2.a[1].set(Some(&b3));
+
+    b3.a[0].set(Some(&b1));
+    b3.a[1].set(Some(&b2));
+}

src/test/ui/array-slice-vec/arr_cycle.rs

@@ -1,31 +0,0 @@
-// run-pass
-
-use std::cell::Cell;
-
-#[derive(Debug)]
-struct B<'a> {
-    a: [Cell<Option<&'a B<'a>>>; 2]
-}
-
-impl<'a> B<'a> {
-    fn new() -> B<'a> {
-        B { a: [Cell::new(None), Cell::new(None)] }
-    }
-}
-
-fn f() {
-    let (b1, b2, b3);
-    b1 = B::new();
-    b2 = B::new();
-    b3 = B::new();
-    b1.a[0].set(Some(&b2));
-    b1.a[1].set(Some(&b3));
-    b2.a[0].set(Some(&b2));
-    b2.a[1].set(Some(&b3));
-    b3.a[0].set(Some(&b1));
-    b3.a[1].set(Some(&b2));
-}
-
-fn main() {
-    f();
-}