What #[derive(IsVariant)] generates

When an enum is decorated with #[derive(IsVariant)], for each variant foo in the enum, a public instance method is_foo(&self) -> bool is generated. If you don’t want the is_foo method generated for a variant you can put the #[is_variant(ignore)] attribute on that variant.

1 Example usage

enum Maybe<T> {

fn main(){

2 What is generated?

The derive in the above example code generates the following code:

impl <T> Maybe<T>{
    pub fn is_just(&self) -> bool {
        match self {Self::Just(..) => true, _ => false}
    pub fn is_nothing(&self) -> bool {
        match self {Self::Nothing => true, _ => false}