1 #![deny(meta_variable_misuse)] 2 3 macro_rules! foo { 4 () => {}; 5 (error) => { 6 macro_rules! bar { 7 ($x:tt $x:tt) => { $x }; //~ ERROR duplicate matcher binding 8 } 9 }; 10 } 11 main()12 fn main() { 13 foo!(); 14 } 15