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#![deny(clippy::pedantic)]
#![deny(clippy::all)]
//! Tests if a trivial functor, which's lifetime depends on the mapping function, works.
use higher::{Bind, Functor};
use higher_free_macro::free;
use std::rc::Rc;
#[derive(Clone)]
struct TrivWithLifetime<'a, A, B> {
next: Rc<dyn Fn(B) -> A + 'a>,
}
impl<'a, A: 'a, B: 'a> Functor<'a, A> for TrivWithLifetime<'a, A, B> {
type Target<T> = TrivWithLifetime<'a, T, B>;
fn fmap<C, F>(self, f: F) -> Self::Target<C>
where
F: Fn(A) -> C + 'a,
{
TrivWithLifetime {
next: Rc::new(move |x| f((self.next)(x))),
}
}
}
free!(<'a>, FreeTriv<'a,A,B>, TrivWithLifetime<'a,FreeTriv<'a,A,B>,B>);
#[test]
fn test_trivial_with_lifetime() {
let f = FreeTriv::lift_f(TrivWithLifetime {
next: Rc::new(i32::unsigned_abs),
});
let f = f.bind(FreeTriv::Pure);
match f {
FreeTriv::Free(f) => {
let n = (f.next)(-4);
match n {
FreeTriv::Pure(v) => assert_eq!(v, 4u32),
FreeTriv::Free(_) => unreachable!(),
}
}
FreeTriv::Pure(_) => unreachable!(),
}
}
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