#![feature(let_chains)] trait Demo {} impl dyn Demo { pub fn report(&self) -> u32 { let sum = |a: u32, b: u32, c: u32| { a + b + c }; sum(1, 2, 3) } fn check(&self, val: Option, num: Option) { if let Some(b) = val && let Some(c) = num { && b == c { } } } fn main() { } //~ ERROR this file contains an unclosed delimiter