// run-rustfix #![allow( unused, clippy::assign_op_pattern, clippy::blocks_in_if_conditions, clippy::let_and_return, clippy::let_unit_value, clippy::nonminimal_bool )] use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet}; use std::rc::Rc; struct SignificantDrop; impl std::ops::Drop for SignificantDrop { fn drop(&mut self) { println!("dropped"); } } fn simple() { let a; a = "zero"; let b; let c; b = 1; c = 2; let d: usize; d = 1; let e; e = format!("{}", d); } fn main() { let a; let n = 1; match n { 1 => a = "one", _ => { a = "two"; }, } let b; if n == 3 { b = "four"; } else { b = "five" } let d; if true { let temp = 5; d = temp; } else { d = 15; } let e; if true { e = format!("{} {}", a, b); } else { e = format!("{}", n); } let f; match 1 { 1 => f = "three", _ => return, }; // has semi let g: usize; if true { g = 5; } else { panic!(); } // Drop order only matters if both are significant let x; let y = SignificantDrop; x = 1; let x; let y = 1; x = SignificantDrop; let x; // types that should be considered insignificant let y = 1; let y = "2"; let y = String::new(); let y = vec![3.0]; let y = HashMap::::new(); let y = BTreeMap::::new(); let y = HashSet::::new(); let y = BTreeSet::::new(); let y = Box::new(4); x = SignificantDrop; } async fn in_async() -> &'static str { async fn f() -> &'static str { "one" } let a; let n = 1; match n { 1 => a = f().await, _ => { a = "two"; }, } a } const fn in_const() -> &'static str { const fn f() -> &'static str { "one" } let a; let n = 1; match n { 1 => a = f(), _ => { a = "two"; }, } a } fn does_not_lint() { let z; if false { z = 1; } let x; let y; if true { x = 1; } else { y = 1; } let mut x; if true { x = 5; x = 10 / x; } else { x = 2; } let x; let _ = match 1 { 1 => x = 10, _ => x = 20, }; // using tuples would be possible, but not always preferable let x; let y; if true { x = 1; y = 2; } else { x = 3; y = 4; } // could match with a smarter heuristic to avoid multiple assignments let x; if true { let mut y = 5; y = 6; x = y; } else { x = 2; } let (x, y); if true { x = 1; } else { x = 2; } y = 3; macro_rules! assign { ($i:ident) => { $i = 1; }; } let x; assign!(x); let x; if true { assign!(x); } else { x = 2; } macro_rules! in_macro { () => { let x; x = 1; let x; if true { x = 1; } else { x = 2; } }; } in_macro!(); // ignore if-lets - https://github.com/rust-lang/rust-clippy/issues/8613 let x; if let Some(n) = Some("v") { x = 1; } else { x = 2; } let x; if true && let Some(n) = Some("let chains too") { x = 1; } else { x = 2; } // ignore mut bindings // https://github.com/shepmaster/twox-hash/blob/b169c16d86eb8ea4a296b0acb9d00ca7e3c3005f/src/sixty_four.rs#L88-L93 // https://github.com/dtolnay/thiserror/blob/21c26903e29cb92ba1a7ff11e82ae2001646b60d/tests/test_generics.rs#L91-L100 let mut x: usize; x = 1; x = 2; x = 3; // should not move the declaration if `x` has a significant drop, and there // is another binding with a significant drop between it and the first usage let x; let y = SignificantDrop; x = SignificantDrop; } #[rustfmt::skip] fn issue8911() -> u32 { let x; match 1 { _ if { x = 1; false } => return 1, _ => return 2, } let x; if { x = 1; true } { return 1; } else { return 2; } 3 }