macro_rules! ignored_item { () => { fn foo() {} fn bar() {} , //~ ERROR macro expansion ignores `,` } } macro_rules! ignored_expr { () => ( 1, //~ ERROR expected one of `.`, `;`, `?`, `}`, or an operator, found `,` 2 ) } macro_rules! ignored_pat { () => ( 1, 2 ) //~ ERROR macro expansion ignores `,` } ignored_item!(); fn main() { ignored_expr!(); match 1 { ignored_pat!() => (), _ => (), } }