//@aux-build:proc_macros.rs #![warn(clippy::mem_replace_with_default)] extern crate proc_macros; use proc_macros::{external, inline_macros}; #[inline_macros] fn main() { let s = &mut String::from("foo"); let _ = inline!(std::mem::replace($s, Default::default())); let _ = external!(std::mem::replace($s, Default::default())); }