Document underscore lifetime elision #334
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src/lifetime-elision.md
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| The following rules are used to infer lifetime parameters for elided lifetimes. | ||
| It is an error to elide lifetime parameters that cannot be inferred. | ||
| An elided lifetime can be specified either by omitting it, or by using `'_`. | ||
| For lifetimes in paths, using `'_` is preferred. The following rules are used |
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A few things here:
- What is a lifetime in a path? Do you mean as a parameter?
- Should probably mention that omitting a lifetime in a trait object type is equivalent to
'static, not'_.
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Also, is '_ not preferred for references as well? I thought omitting lifetimes was going to be deprecated.
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Comments addressed.
The RFC says
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matthewjasper
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Ah, my bad, excellent. |
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src/lifetime-elision.md
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| parameter elision rules defined above. | ||
| [RFC 1156]. | ||
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| > These default object lifetime bounds are used instead of the lifetime |
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Is this supposed to be a Note?
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Well, it was intentional. I've changed it back to normal prose now.
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src/lifetime-elision.md
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| *elided* in [function item], [function pointer] and [closure trait] signatures. | ||
| The following rules are used to infer lifetime parameters for elided lifetimes. | ||
| It is an error to elide lifetime parameters that cannot be inferred. | ||
| In order to make common patterns more ergonomic, Rust allows lifetime argument |
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Can you remove the "Rust allows" here? Would have to change the wording a bit too. I can do it in a follow up PR if you don't want to.
cc #278 There don't seem to be any cases where
'_could be used outside of this chapter.'_can also be used for inferred lifetimes, but I don't think there is any documentation for them yet.Also uses dyn trait in the elision chapter (cc #279)