Clarify the English translation of ?Sized
#33747
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* It wasn't clear whether `?Sized` meant "not `Sized`" or "`Sized` or not `Sized`". According to #rust IRC, it does indeed mean "`Sized` or not `Sized`". * Use the same language as [Trait std::marker::Sized](https://doc.rust-lang.org/std/marker/trait.Sized.html) about how `Sized` is implicitly bound.
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| lets us match more kinds, not less. It’s almost like every `T` implicitly has | ||
| `T: Sized`, and the `?` undoes this default. | ||
| This `?Sized`, read as “T may or may not be `Sized`”, allowing us to match both constant size and unsized types. | ||
| All generic type parameters implicitly have the `Sized` bound, so `?Sized` can be used to opt-out of the implicit bound. |
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Small nit, the line wrapping here is different to the rest of the file, it should probably be whatever the rest of the text is (looks like 80 chars?).
| This `?`, read as “T may be `Sized`”, means that this bound is special: it | ||
| lets us match more kinds, not less. It’s almost like every `T` implicitly has | ||
| `T: Sized`, and the `?` undoes this default. | ||
| This `?Sized`, read as “T may or may not be `Sized`”, allowing us to match both |
| This `?Sized`, read as “T may or may not be `Sized`”, allowing us to match both | ||
| constant size and unsized types. All generic type parameters implicitly have | ||
| the `Sized` bound, so `?Sized` can be used to opt-out of the implicit bound. | ||
| This `?Sized`, read as “T may or may not be `Sized`”, which allows us to match |
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Sorry, I think this is still not quite right...
My understanding is that you should be able to remove the appositive (the part between the commas) and still have a valid sentence. So I think the word "which" here is extraneous.
I'd prefer if someone else could chime in here as well on the grammar.
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I'm horrible with grammar, so I'll defer.
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Thanks for this @postmodern ! It is an area where, like the feature itself, the docs are a bit patched together.... |
* Use "special bound syntax" instead of "special syntax". `?Sized` is technically a "bound", but `?Sized` is specialized syntax that _only_ works with `Sized`, and no other Trait. * Replace "constant size" with "sized".
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Edited yet again. I now refer to |
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@bors r+ rollup |
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📌 Commit 71af58a has been approved by |
Clarify the English translation of `?Sized` * It wasn't clear whether `?Sized` meant "not `Sized`" or "`Sized` or not `Sized`". According to #rust IRC, it does indeed mean "`Sized` or not `Sized`". * Use the same language as [Trait std::marker::Sized](https://doc.rust-lang.org/std/marker/trait.Sized.html) about how `Sized` is implicitly bound. * Refer to the syntax as `?Sized`, since it's currently the only allowed trait that can follow `?`.
| lets us match more kinds, not less. It’s almost like every `T` implicitly has | ||
| `T: Sized`, and the `?` undoes this default. | ||
| This `?Sized`, read as “T may or may not be `Sized`”, which allows us to match | ||
| both sized and unsized types. All generic type parameters implicitly |
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"which" should be removed from the first sentence.
?Sizedmeant "notSized" or "Sizedor notSized". According to #rust IRC, it does indeed mean "Sizedor notSized".Sizedis implicitly bound.?Sized, since it's currently the only allowed trait that can follow?.