#![allow(clippy::trivially_copy_pass_by_ref)] fn fn_val(i: i32) -> i32 { unimplemented!() } fn fn_constref(i: &i32) -> i32 { unimplemented!() } fn fn_mutref(i: &mut i32) { unimplemented!() } fn fooi() -> i32 { unimplemented!() } fn foob() -> bool { unimplemented!() } #[allow(clippy::many_single_char_names)] fn immutable_condition() { // Should warn when all vars mentioned are immutable let y = 0; while y < 10 { println!("KO - y is immutable"); } let x = 0; while y < 10 && x < 3 { let mut k = 1; k += 2; println!("KO - x and y immutable"); } let cond = false; while !cond { println!("KO - cond immutable"); } let mut i = 0; while y < 10 && i < 3 { i += 1; println!("OK - i is mutable"); } let mut mut_cond = false; while !mut_cond || cond { mut_cond = true; println!("OK - mut_cond is mutable"); } while fooi() < x { println!("OK - Fn call results may vary"); } while foob() { println!("OK - Fn call results may vary"); } let mut a = 0; let mut c = move || { while a < 5 { a += 1; println!("OK - a is mutable"); } }; c(); let mut tup = (0, 0); while tup.0 < 5 { tup.0 += 1; println!("OK - tup.0 gets mutated") } } fn unused_var() { // Should warn when a (mutable) var is not used in while body let (mut i, mut j) = (0, 0); while i < 3 { j = 3; println!("KO - i not mentioned"); } while i < 3 && j > 0 { println!("KO - i and j not mentioned"); } while i < 3 { let mut i = 5; fn_mutref(&mut i); println!("KO - shadowed"); } while i < 3 && j > 0 { i = 5; println!("OK - i in cond and mentioned"); } } fn used_immutable() { let mut i = 0; while i < 3 { fn_constref(&i); println!("KO - const reference"); } while i < 3 { fn_val(i); println!("KO - passed by value"); } while i < 3 { println!("OK - passed by mutable reference"); fn_mutref(&mut i) } while i < 3 { fn_mutref(&mut i); println!("OK - passed by mutable reference"); } } const N: i32 = 5; const B: bool = false; fn consts() { while false { println!("Constants are not linted"); } while B { println!("Constants are not linted"); } while N > 0 { println!("Constants are not linted"); } } use std::cell::Cell; fn maybe_i_mutate(i: &Cell<bool>) { unimplemented!() } fn internally_mutable() { let b = Cell::new(true); while b.get() { // b cannot be silently coerced to `bool` maybe_i_mutate(&b); println!("OK - Method call within condition"); } } struct Counter { count: usize, } impl Counter { fn inc(&mut self) { self.count += 1; } fn inc_n(&mut self, n: usize) { while self.count < n { self.inc(); } println!("OK - self borrowed mutably"); } fn print_n(&self, n: usize) { while self.count < n { println!("KO - {} is not mutated", self.count); } } } fn while_loop_with_break_and_return() { let y = 0; while y < 10 { if y == 0 { break; } println!("KO - loop contains break"); } while y < 10 { if y == 0 { return; } println!("KO - loop contains return"); } } fn main() { immutable_condition(); unused_var(); used_immutable(); internally_mutable(); let mut c = Counter { count: 0 }; c.inc_n(5); c.print_n(2); while_loop_with_break_and_return(); }