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use std::ops::Range;
trait Itble<'r, T, I: Iterator<Item=T>> { fn iter(&'r self) -> I; }
impl<'r> Itble<'r, usize, Range<usize>> for (usize, usize) {
fn iter(&'r self) -> Range<usize> {
let &(min, max) = self;
min..max
}
}
fn check<'r, I: Iterator<Item=usize>, T: Itble<'r, usize, I>>(cont: &T) -> bool
{
let cont_iter = cont.iter();
//~^ ERROR explicit lifetime required in the type of `cont` [E0621]
let result = cont_iter.fold(Some(0), |state, val| {
state.map_or(None, |mask| {
let bit = 1 << val;
if mask & bit == 0 {Some(mask|bit)} else {None}
})
});
result.is_some()
}
fn main() {
check(&(3, 5));
}
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