mirror of https://github.com/rust-lang/rust
51 lines
1.4 KiB
Rust
51 lines
1.4 KiB
Rust
//@ run-pass
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//@ pretty-expanded FIXME #23616
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fn main() {
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let _ = test(Some(0).into_iter());
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}
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trait Parser {
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type Input: Iterator;
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type Output;
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fn parse(self, input: Self::Input) -> Result<(Self::Output, Self::Input), ()>;
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fn chain<P>(self, p: P) -> Chain<Self, P> where Self: Sized {
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Chain(self, p)
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}
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}
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struct Token<T>(#[allow(dead_code)] T::Item) where T: Iterator;
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impl<T> Parser for Token<T> where T: Iterator {
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type Input = T;
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type Output = T::Item;
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fn parse(self, _input: Self::Input) -> Result<(Self::Output, Self::Input), ()> {
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Err(())
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}
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}
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struct Chain<L, R>(#[allow(dead_code)] L, #[allow(dead_code)] R);
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impl<L, R> Parser for Chain<L, R> where L: Parser, R: Parser<Input = L::Input> {
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type Input = L::Input;
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type Output = (L::Output, R::Output);
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fn parse(self, _input: Self::Input) -> Result<(Self::Output, Self::Input), ()> {
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Err(())
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}
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}
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fn test<I>(i: I) -> Result<((), I), ()> where I: Iterator<Item = i32> {
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Chain(Token(0), Token(1))
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.chain(Chain(Token(0), Token(1)))
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.chain(Chain(Token(0), Token(1)))
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.chain(Chain(Token(0), Token(1)))
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.chain(Chain(Token(0), Token(1)))
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.chain(Chain(Token(0), Token(1)))
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.chain(Chain(Token(0), Token(1)))
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.chain(Chain(Token(0), Token(1)))
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.chain(Chain(Token(0), Token(1)))
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.parse(i)
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.map(|(_, i)| ((), i))
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}
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