73 lines
1.5 KiB
Rust
73 lines
1.5 KiB
Rust
trait Foo {}
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impl<'a, T: Foo> Foo for &'a T {}
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impl<T: Foo + ?Sized> Foo for Box<T> {}
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struct Iter<'a, T> {
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current: Option<Box<dyn Foo + 'a>>,
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remaining: T,
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}
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impl<'a, T> Iterator for Iter<'a, T>
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where
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T: Iterator,
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T::Item: Foo + 'a,
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{
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type Item = Box<dyn Foo + 'a>;
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fn next(&mut self) -> Option<Self::Item> {
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let result = self.current.take();
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self.current = Box::new(self.remaining.next()).map(|f| Box::new(f) as _);
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result
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}
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}
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struct Bar(Vec<Box<dyn Foo>>);
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impl Bar {
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fn iter(&self) -> impl Iterator<Item = Box<dyn Foo>> {
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Iter {
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//~^ ERROR lifetime may not live long enough
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current: None,
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remaining: self.0.iter(),
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}
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}
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}
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struct Baz(Vec<Box<dyn Foo>>);
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impl Baz {
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fn iter(&self) -> impl Iterator<Item = Box<dyn Foo>> + '_ {
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Iter {
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//~^ ERROR lifetime may not live long enough
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current: None,
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remaining: self.0.iter(),
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}
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}
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}
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struct Bat(Vec<Box<dyn Foo>>);
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impl Bat {
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fn iter<'a>(&'a self) -> impl Iterator<Item = Box<dyn Foo>> + 'a {
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Iter {
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//~^ ERROR lifetime may not live long enough
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current: None,
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remaining: self.0.iter(),
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}
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}
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}
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struct Ban(Vec<Box<dyn Foo>>);
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impl Ban {
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fn iter<'a>(&'a self) -> impl Iterator<Item = Box<dyn Foo>> {
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Iter {
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//~^ ERROR lifetime may not live long enough
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current: None,
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remaining: self.0.iter(),
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}
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}
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}
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fn main() {}
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