31 lines
444 B
Rust
31 lines
444 B
Rust
// check-pass
|
|
|
|
#![feature(const_trait_impl)]
|
|
|
|
const fn answer_p1<F>(f: &F) -> u8
|
|
where
|
|
F: ~const FnOnce() -> u8,
|
|
F: ~const FnMut() -> u8,
|
|
F: ~const Fn() -> u8,
|
|
{
|
|
f() * 7
|
|
}
|
|
|
|
const fn three() -> u8 {
|
|
3
|
|
}
|
|
|
|
const fn answer_p2() -> u8 {
|
|
answer_p1(&three)
|
|
}
|
|
|
|
const fn answer<F: ~const Fn() -> u8>(f: &F) -> u8 {
|
|
f() + f()
|
|
}
|
|
|
|
const ANSWER: u8 = answer(&answer_p2);
|
|
|
|
fn main() {
|
|
assert_eq!(ANSWER, 42)
|
|
}
|