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//@ run-pass
fn main() {
let _ = test(Some(0).into_iter());
}
trait Parser {
type Input: Iterator;
type Output;
fn parse(self, input: Self::Input) -> Result<(Self::Output, Self::Input), ()>;
fn chain<P>(self, p: P) -> Chain<Self, P> where Self: Sized {
Chain(self, p)
}
}
struct Token<T>(#[allow(dead_code)] T::Item) where T: Iterator;
impl<T> Parser for Token<T> where T: Iterator {
type Input = T;
type Output = T::Item;
fn parse(self, _input: Self::Input) -> Result<(Self::Output, Self::Input), ()> {
Err(())
}
}
struct Chain<L, R>(#[allow(dead_code)] L, #[allow(dead_code)] R);
impl<L, R> Parser for Chain<L, R> where L: Parser, R: Parser<Input = L::Input> {
type Input = L::Input;
type Output = (L::Output, R::Output);
fn parse(self, _input: Self::Input) -> Result<(Self::Output, Self::Input), ()> {
Err(())
}
}
fn test<I>(i: I) -> Result<((), I), ()> where I: Iterator<Item = i32> {
Chain(Token(0), Token(1))
.chain(Chain(Token(0), Token(1)))
.chain(Chain(Token(0), Token(1)))
.chain(Chain(Token(0), Token(1)))
.chain(Chain(Token(0), Token(1)))
.chain(Chain(Token(0), Token(1)))
.chain(Chain(Token(0), Token(1)))
.chain(Chain(Token(0), Token(1)))
.chain(Chain(Token(0), Token(1)))
.parse(i)
.map(|(_, i)| ((), i))
}
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