Function dbg_contains 

pub fn dbg_contains<'v, V, I>(value: V, item: I) -> Result<'v, ()>
where
    V: Contains<I>,
    I: Debug + Copy,

Debug contains validator: like contains() but mentions item in the error message.

This is the dual of dbg_omits(). The is identical to contains() except that item must be Debug + Copy and the error message is as follows, where $item is the Debug representation of item:

values must contains $item

If the collection is empty, this validator fails.

Example

use rocket::form::{FromForm, FromFormField};

#[derive(PartialEq, Debug, Clone, Copy, FromFormField)]
enum Pet { Cat, Dog }

#[derive(FromForm)]
struct Foo {
    best_pet: Pet,
    #[field(validate = dbg_contains(Pet::Dog))]
    #[field(validate = dbg_contains(&self.best_pet))]
    pets: Vec<Pet>,
}