macro_rules! impl_display_for_single_struct { ($Name: ident, $name: tt $(. $attr: tt)*) => { ... }; ($Name: ident) => { ... }; }
macro_rules! impl_display_for_single_struct { ($Name: ident, $name: tt $(. $attr: tt)*) => { ... }; ($Name: ident) => { ... }; }