Implement RefCell::{try_borrow, try_borrow_mut}
#35425
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The error structs may want to implement some additional traits, but those can be added later. |
| #[derive(Clone, Debug)] | ||
| #[unstable(feature = "try_borrow", issue = "35070")] | ||
| pub struct BorrowError { | ||
| _inner: (), |
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What _inner field for?
You can write just
pub struct BorrowError {
}
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This way it can't be constructed outside the module
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Yeah, I copied this from the RFC itself, and it can always be removed before being stabilized.
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Thanks @apasel422! To be maximally conservative as well, could you add a lifetime parameter to the two error types so it's connected to struct Error<'a, T> {
inner: marker::PhantomData<&'a RefCell<T>>,
}Also, could you be sure to add |
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@alexcrichton Sure. Do you still want a |
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Nah it should be fine to omit for now I think |
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Updated. |
| not be exposed publicly", | ||
| issue = "0")] | ||
| #[doc(hidden)] | ||
| pub fn __description(&self) -> &str { |
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Despite this being how std::num does it in a few locations, that's just because the variants in core aren't available in std. For something like these errors it should be fine to just put this error string directly into std, no need to worry about reducing the duplication of this string literal!
Implement `RefCell::{try_borrow, try_borrow_mut}`
CC #35070
r? @alexcrichton
CC #35070
r? @alexcrichton