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// run-pass
#![allow(unused_must_use)]
#![allow(dead_code)]
// pretty-expanded FIXME #23616
trait Matcher {
fn next_match(&mut self) -> Option<(usize, usize)>;
}
struct CharPredMatcher<'a, 'b> {
str: &'a str,
pred: Box<dyn FnMut(char) -> bool + 'b>,
}
impl<'a, 'b> Matcher for CharPredMatcher<'a, 'b> {
fn next_match(&mut self) -> Option<(usize, usize)> {
None
}
}
trait IntoMatcher<'a, T> {
fn into_matcher(self, _: &'a str) -> T;
}
impl<'a, 'b, F> IntoMatcher<'a, CharPredMatcher<'a, 'b>> for F where F: FnMut(char) -> bool + 'b {
fn into_matcher(self, s: &'a str) -> CharPredMatcher<'a, 'b> {
CharPredMatcher {
str: s,
pred: Box::new(self),
}
}
}
struct MatchIndices<M> {
matcher: M
}
impl<M: Matcher> Iterator for MatchIndices<M> {
type Item = (usize, usize);
fn next(&mut self) -> Option<(usize, usize)> {
self.matcher.next_match()
}
}
fn match_indices<'a, M, T: IntoMatcher<'a, M>>(s: &'a str, from: T) -> MatchIndices<M> {
let string_matcher = from.into_matcher(s);
MatchIndices { matcher: string_matcher }
}
fn main() {
let s = "abcbdef";
match_indices(s, |c: char| c == 'b')
.collect::<Vec<_>>();
}
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