36 lines
636 B
Rust
36 lines
636 B
Rust
//@ check-pass
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#![feature(specialization)] //~ WARN the feature `specialization` is incomplete
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pub struct Cloned<I>(I);
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impl<'a, I, T: 'a> Iterator for Cloned<I>
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where
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I: Iterator<Item = &'a T>,
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T: Clone,
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{
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type Item = T;
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fn next(&mut self) -> Option<T> {
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unimplemented!()
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}
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default fn count(self) -> usize where Self: Sized {
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self.fold(0, |cnt, _| cnt + 1)
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}
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}
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impl<'a, I, T: 'a> Iterator for Cloned<I>
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where
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I: Iterator<Item = &'a T>,
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T: Copy,
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{
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fn count(self) -> usize {
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unimplemented!()
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}
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}
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fn main() {
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let a = [1,2,3,4];
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Cloned(a.iter()).count();
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}
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