// run-pass #![allow(unused_parens)] fn region_identity(x: &usize) -> &usize { x } fn apply(t: T, f: F) -> T where F: FnOnce(T) -> T { f(t) } fn parameterized(x: &usize) -> usize { let z = apply(x, ({|y| region_identity(y) })); *z } pub fn main() { let x = 3; assert_eq!(parameterized(&x), 3); }