37 lines
988 B
Rust
37 lines
988 B
Rust
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//@ edition: 2021
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#![feature(async_closure)]
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struct NotClonableArg;
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#[derive(Default)]
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struct NotClonableReturnType;
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// Verify that the only components that we care about are the upvars, not the signature.
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fn we_are_okay_with_not_clonable_signature() {
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let x = async |x: NotClonableArg| -> NotClonableReturnType { Default::default() };
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x.clone(); // Okay
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}
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#[derive(Debug)]
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struct NotClonableUpvar;
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fn we_only_care_about_clonable_upvars() {
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let x = NotClonableUpvar;
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// Notably, this is clone because we capture `&x`.
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let yes_clone = async || {
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println!("{x:?}");
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};
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yes_clone.clone(); // Okay
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let z = NotClonableUpvar;
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// However, this is not because the closure captures `z` by move.
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// (Even though the future that is lent out captures `z by ref!)
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let not_clone = async move || {
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println!("{z:?}");
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};
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not_clone.clone();
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//~^ ERROR the trait bound `NotClonableUpvar: Clone` is not satisfied
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}
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fn main() {}
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