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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 arbitrary expressions aren't allowed in patterns
});
fn main() {}
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