// Creating a stack closure which references a box and then // transferring ownership of the box before invoking the stack // closure results in a crash. #![feature(box_syntax)] fn twice(x: Box) -> usize { *x * 2 } fn invoke(f: F) where F: FnOnce() -> usize { f(); } fn main() { let x : Box = box 9; let sq = || { *x * *x }; twice(x); //~ ERROR: cannot move out of invoke(sq); }