51 lines
1.1 KiB
Rust
51 lines
1.1 KiB
Rust
// run-pass
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#![allow(unused_imports)]
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// Test for an ICE that occurred when a default method implementation
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// was applied to a type that did not meet the prerequisites. The
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// problem occurred specifically because normalizing
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// `Self::Item::Target` was impossible in this case.
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use std::boxed::Box;
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use std::marker::Sized;
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use std::clone::Clone;
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use std::ops::Deref;
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use std::option::Option;
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use std::option::Option::{Some,None};
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trait Iterator {
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type Item;
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fn next(&mut self) -> Option<Self::Item>;
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fn clone_first(mut self) -> Option<<Self::Item as Deref>::Target> where
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Self: Sized,
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Self::Item: Deref,
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<Self::Item as Deref>::Target: Clone,
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{
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self.next().map(|x| x.clone())
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}
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}
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struct Counter {
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value: i32
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}
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struct Token {
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value: i32
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}
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impl Iterator for Counter {
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type Item = Token;
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fn next(&mut self) -> Option<Token> {
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let x = self.value;
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self.value += 1;
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Some(Token { value: x })
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}
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}
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fn main() {
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let mut x: Box<dyn Iterator<Item=Token>> = Box::new(Counter { value: 22 });
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assert_eq!(x.next().unwrap().value, 22);
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}
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