#![warn(clippy::ineffective_open_options)] use std::fs::OpenOptions; fn main() { let file = OpenOptions::new() .create(true) .write(true) //~ ERROR: unnecessary use of `.write(true)` .append(true) .open("dump.json") .unwrap(); let file = OpenOptions::new() .create(true) .append(true) .write(true) //~ ERROR: unnecessary use of `.write(true)` .open("dump.json") .unwrap(); // All the next calls are ok. let file = OpenOptions::new() .create(true) .write(false) .append(true) .open("dump.json") .unwrap(); let file = OpenOptions::new() .create(true) .write(true) .append(false) .open("dump.json") .unwrap(); let file = OpenOptions::new() .create(true) .write(false) .append(false) .open("dump.json") .unwrap(); let file = OpenOptions::new().create(true).append(true).open("dump.json").unwrap(); let file = OpenOptions::new().create(true).write(true).open("dump.json").unwrap(); }