mirror of https://github.com/rust-lang/rust
30 lines
563 B
Rust
30 lines
563 B
Rust
//@ check-pass
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pub trait Trait1 {
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type C;
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}
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struct T1;
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impl Trait1 for T1 {
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type C = usize;
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}
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pub trait Callback<T: Trait1>: FnMut(<T as Trait1>::C) {}
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impl<T: Trait1, F: FnMut(<T as Trait1>::C)> Callback<T> for F {}
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pub struct State<T: Trait1> {
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callback: Option<Box<dyn Callback<T>>>,
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}
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impl<T: Trait1> State<T> {
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fn new() -> Self {
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Self { callback: None }
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}
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fn test_cb(&mut self, d: <T as Trait1>::C) {
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(self.callback.as_mut().unwrap())(d)
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}
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}
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fn main() {
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let mut s = State::<T1>::new();
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s.test_cb(1);
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}
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