53 lines
1.3 KiB
Rust
53 lines
1.3 KiB
Rust
#![warn(clippy::double_ended_iterator_last)]
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// Typical case
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pub fn last_arg(s: &str) -> Option<&str> {
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s.split(' ').last()
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}
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fn main() {
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// General case
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struct DeIterator;
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impl Iterator for DeIterator {
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type Item = ();
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fn next(&mut self) -> Option<Self::Item> {
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Some(())
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}
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}
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impl DoubleEndedIterator for DeIterator {
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fn next_back(&mut self) -> Option<Self::Item> {
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Some(())
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}
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}
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let _ = DeIterator.last();
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// Should not apply to other methods of Iterator
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let _ = DeIterator.count();
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// Should not apply to simple iterators
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struct SimpleIterator;
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impl Iterator for SimpleIterator {
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type Item = ();
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fn next(&mut self) -> Option<Self::Item> {
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Some(())
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}
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}
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let _ = SimpleIterator.last();
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// Should not apply to custom implementations of last()
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struct CustomLast;
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impl Iterator for CustomLast {
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type Item = ();
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fn next(&mut self) -> Option<Self::Item> {
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Some(())
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}
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fn last(self) -> Option<Self::Item> {
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Some(())
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}
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}
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impl DoubleEndedIterator for CustomLast {
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fn next_back(&mut self) -> Option<Self::Item> {
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Some(())
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}
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}
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let _ = CustomLast.last();
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}
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