// check-pass #![feature(const_generics)] //~^ WARN the feature `const_generics` is incomplete struct Foo { state: Option<[u8; D]>, } impl Iterator for Foo<{D}> { type Item = [u8; D]; fn next(&mut self) -> Option { if true { return Some(self.state.unwrap().clone()); } else { return Some(self.state.unwrap().clone()); } } } fn main() {}