//@aux-build:proc_macros.rs:proc-macro #![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"); inline!(std::mem::replace($s, Default::default())); external!(std::mem::replace($s, Default::default())); }