error: no rules expected the token `_` --> $DIR/underscore-ident-matcher.rs:8:19 | LL | macro_rules! identity { | --------------------- when calling this macro ... LL | let identity!(_) = 10; | ^ no rules expected this token in macro call | note: while trying to match meta-variable `$i:ident` --> $DIR/underscore-ident-matcher.rs:2:6 | LL | ($i: ident) => ( | ^^^^^^^^^ error: aborting due to previous error