``` rust fn main() { let count = @mut 0u; let mut map = core::hashmap::linear::LinearMap::new(); let mut arr = ~[]; for uint::range(0u, 10u) |i| { arr += ~[@~"key stuff"]; map.insert(copy arr, arr + ~[@~"value stuff"]); if arr.len() == 5 { fail!(); } } } ``` This is similar to #4547, but it could be a different issue.