// run-rustfix use std::cmp::Reverse; fn unnecessary_sort_by() { fn id(x: isize) -> isize { x } let mut vec: Vec = vec![3, 6, 1, 2, 5]; // Forward examples vec.sort_by(|a, b| a.cmp(b)); vec.sort_unstable_by(|a, b| a.cmp(b)); vec.sort_by(|a, b| (a + 5).abs().cmp(&(b + 5).abs())); vec.sort_unstable_by(|a, b| id(-a).cmp(&id(-b))); // Reverse examples vec.sort_by(|a, b| b.cmp(a)); vec.sort_by(|a, b| (b + 5).abs().cmp(&(a + 5).abs())); vec.sort_unstable_by(|a, b| id(-b).cmp(&id(-a))); // Negative examples (shouldn't be changed) let c = &7; vec.sort_by(|a, b| (b - a).cmp(&(a - b))); vec.sort_by(|_, b| b.cmp(&5)); vec.sort_by(|_, b| b.cmp(c)); vec.sort_unstable_by(|a, _| a.cmp(c)); } // Should not be linted to avoid hitting https://github.com/rust-lang/rust/issues/34162 mod issue_5754 { struct Test(String); #[derive(PartialOrd, Ord, PartialEq, Eq)] struct Wrapper<'a>(&'a str); impl Test { fn name(&self) -> &str { &self.0 } fn wrapped(&self) -> Wrapper<'_> { Wrapper(&self.0) } } pub fn test() { let mut args: Vec = vec![]; // Forward args.sort_by(|a, b| a.name().cmp(b.name())); args.sort_by(|a, b| a.wrapped().cmp(&b.wrapped())); args.sort_unstable_by(|a, b| a.name().cmp(b.name())); args.sort_unstable_by(|a, b| a.wrapped().cmp(&b.wrapped())); // Reverse args.sort_by(|a, b| b.name().cmp(a.name())); args.sort_by(|a, b| b.wrapped().cmp(&a.wrapped())); args.sort_unstable_by(|a, b| b.name().cmp(a.name())); args.sort_unstable_by(|a, b| b.wrapped().cmp(&a.wrapped())); } } fn main() { unnecessary_sort_by(); issue_5754::test(); }