32 lines
706 B
Rust
32 lines
706 B
Rust
|
// compile-flags: -Zvalidate-mir -C opt-level=3
|
||
|
|
// build-pass
|
||
|
|
#![feature(let_chains)]
|
||
|
|
struct TupleIter<T, I: Iterator<Item = T>> {
|
||
|
|
inner: I,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl<T, I: Iterator<Item = T>> Iterator for TupleIter<T, I> {
|
||
|
|
type Item = (T, T, T);
|
||
|
|
|
||
|
|
fn next(&mut self) -> Option<Self::Item> {
|
||
|
|
let inner = &mut self.inner;
|
||
|
|
|
||
|
|
if let Some(first) = inner.next()
|
||
|
|
&& let Some(second) = inner.next()
|
||
|
|
&& let Some(third) = inner.next()
|
||
|
|
{
|
||
|
|
Some((first, second, third))
|
||
|
|
} else {
|
||
|
|
None
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
fn main() {
|
||
|
|
let vec: Vec<u8> = Vec::new();
|
||
|
|
let mut tup_iter = TupleIter {
|
||
|
|
inner: vec.into_iter(),
|
||
|
|
};
|
||
|
|
tup_iter.next();
|
||
|
|
}
|