#![allow(unused, dead_code)] #![warn(clippy::format_collect)] fn hex_encode(bytes: &[u8]) -> String { bytes.iter().map(|b| format!("{b:02X}")).collect() //~^ ERROR: use of `format!` to build up a string from an iterator } #[rustfmt::skip] fn hex_encode_deep(bytes: &[u8]) -> String { bytes.iter().map(|b| {{{{{ format!("{b:02X}") }}}}}).collect() //~^ ERROR: use of `format!` to build up a string from an iterator } macro_rules! fmt { ($x:ident) => { format!("{x:02X}", x = $x) }; } fn from_macro(bytes: &[u8]) -> String { bytes.iter().map(|x| fmt!(x)).collect() } fn with_block() -> String { (1..10) //~^ ERROR: use of `format!` to build up a string from an iterator .map(|s| { let y = 1; format!("{s} {y}") }) .collect() } fn main() {}