warning: struct is never constructed: `S` --> $DIR/macro-span-replacement.rs:17:14 | LL | $b $a; //~ WARN struct is never constructed | ^ ... LL | m!(S struct); | ------------- in this macro invocation | note: lint level defined here --> $DIR/macro-span-replacement.rs:13:9 | LL | #![warn(unused)] | ^^^^^^ = note: #[warn(dead_code)] implied by #[warn(unused)]