| macro_rules! enum_number { |
| ($name:ident { $($variant:ident = $value:expr, )* }) => { |
| enum $name { |
| $($variant = $value,)* |
| } |
| |
| fn foo(value: i32) -> Option<$name> { |
| match value { |
| $( $value => Some($name::$variant), )* // PatKind::Lit |
| $( $value ..= 42 => Some($name::$variant), )* // PatKind::Range |
| _ => None |
| } |
| } |
| } |
| } |
| |
| enum_number!(Change { |
| Pos = 1, |
| Neg = -1, |
| Arith = 1 + 1, //~ ERROR arbitrary expressions aren't allowed in patterns |
| //~^ ERROR only char and numeric types are allowed in range patterns |
| }); |
| |
| fn main() {} |