Add more explanation on RefCell::get_mut #40634
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ghost
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Mar 18, 2017
src/libcore/cell.rs
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| @@ -818,6 +818,12 @@ impl<T: ?Sized> RefCell<T> { | |||
| /// This call borrows `RefCell` mutably (at compile-time) so there is no | |||
| /// need for dynamic checks. | |||
| /// | |||
| /// However be cautious: this method expect `self` to be mutable, which is | |||
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I think the real issue with #40203 is
That is, we need to explain when you would use this method, not just point out that it needs mutable self. |
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Hi @GuillaumeGomez! It looks like @steveklabnik is suggesting some changes to this PR. Just wanted to send a ping to keep this on your radar! |
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Updated (finally!). |
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Nevermind, errors are network related. Restarted the build. |
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@bors: r+ rollup |
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📌 Commit 0b9009e has been approved by |
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🔒 Merge conflict |
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Not sure what went wrong in here... I rebased just in case. @bors: r=steveklabnik rollup |
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📌 Commit 3ad844c has been approved by |
bors
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Apr 24, 2017
Add more explanation on RefCell::get_mut Fixes #40203. r? @rust-lang/docs
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☀️ Test successful - status-appveyor, status-travis |
Dylan-DPC
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Sep 19, 2022
Tone down explanation on RefCell::get_mut
The language around `RefCell::get_mut` is remarkably sketchy and especially to the novice seems to quite strongly discourage using the method ("be cautious", "Also, please be aware", "special circumstances", "usually not what you want"). It was added six years ago in rust-lang#40634 due to confusion about when to use `get_mut` and `borrow_mut`.
While its signature limits the use-cases for `get_mut`, there is no chance for a safety footgun, and readers can be made aware of `borrow_mut` more softly. I've also just sent a [PR](rust-lang/rust-clippy#9044) to lint situations where `get_mut` could be used to improve ergonomics and performance.
So this PR tones down the language around `get_mut` and also brings it more in line with [`std::sync::Mutex::get_mut()`](https://doc.rust-lang.org/stable/std/sync/struct.Mutex.html#method.get_mut).
matthiaskrgr
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Sep 19, 2022
Tone down explanation on RefCell::get_mut
The language around `RefCell::get_mut` is remarkably sketchy and especially to the novice seems to quite strongly discourage using the method ("be cautious", "Also, please be aware", "special circumstances", "usually not what you want"). It was added six years ago in rust-lang#40634 due to confusion about when to use `get_mut` and `borrow_mut`.
While its signature limits the use-cases for `get_mut`, there is no chance for a safety footgun, and readers can be made aware of `borrow_mut` more softly. I've also just sent a [PR](rust-lang/rust-clippy#9044) to lint situations where `get_mut` could be used to improve ergonomics and performance.
So this PR tones down the language around `get_mut` and also brings it more in line with [`std::sync::Mutex::get_mut()`](https://doc.rust-lang.org/stable/std/sync/struct.Mutex.html#method.get_mut).
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Fixes #40203.
r? @rust-lang/docs