| // Copyright 2017 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| 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() {} |