Add as_mut methods to the std::cell structs
#32565
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Would it make sense to make Cell implement One advantage is simplified syntax: A possible disadvantage is that it is surprising for a type to implement Edit: Or, it could implement |
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Implementing |
| /// ``` | ||
| #[inline] | ||
| #[stable(feature = "rust1", since = "1.0.0")] | ||
| pub unsafe fn into_inner(self) -> T { | ||
| pub fn into_inner(self) -> T { |
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This is a stable function so it cannot change.
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Removing an unsafe qualifier shouldn't be a breaking change, right? What code could it break?
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In theory at least it could break code like this:
let f: unsafe fn(Cell<u8>) -> u8 = Cell::<u8>::into_inner;
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Theoretical break isn't enough for it to be considered a major change (see https://github.com/rust-lang/rfcs/blob/master/text/1105-api-evolution.md ), but the RFC does not cover this case.
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Thanks for the PR @tbu-! I don't think we can change |
alexcrichton
added
the
T-libs-api
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Since new users are often confused by special case mutation methods like this (in my experience), the docs need to be clear somehow that this is a special case and regular modification of a Cell uses .set(). |
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The libs team discussed this PR during triage today, and the conclusions were:
Could you make those changes @tbu- and I'll merge? Thanks again for the PR! |
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I made those changes. Note that I also modified the Also, I want to ask whether you really want to name these functions The style document you referenced seems horribly out of date, it tells us to use |
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@tbu- no, let's leave |
This is safe since the borrow checker ensures that we have the only mutable reference to the struct, thus we can safely borrow its interior. Tracking issue is rust-lang#33444.
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@alexcrichton Updated. |
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⌛ Testing commit 9370d3a with merge c02ee81... |
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⛄ The build was interrupted to prioritize another pull request. |
Add `as_mut` methods to the `std::cell` structs This is safe since the borrow checking ensures that we have the only mutable reference to the struct, thus we can safely borrow its interior.
This is safe since the borrow checking ensures that we have the only
mutable reference to the struct, thus we can safely borrow its interior.