// ignore-tidy-linelength // revisions: ast mir //[mir]compile-flags: -Z borrowck=mir #![feature(unboxed_closures)] use std::io::Read; fn to_fn_once>(f: F) -> F { f } fn main() { let x = 1; to_fn_once(move|| { x = 2; }); //[ast]~^ ERROR: cannot assign to immutable captured outer variable //[mir]~^^ ERROR: cannot assign to `x`, as it is not declared as mutable let s = std::io::stdin(); to_fn_once(move|| { s.read_to_end(&mut Vec::new()); }); //[ast]~^ ERROR: cannot borrow immutable captured outer variable //[mir]~^^ ERROR: cannot borrow `s` as mutable, as it is not declared as mutable }