Add lifetime elision information to the ownership guide. #19736
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| fn print<'a>(s: &'a str); // expanded | ||
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| fn debug(lvl: uint, s: &str); // elided | ||
| fn debug<'a>(lvl: uint, s: &'a str); // expanded |
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I think a comment here is warranted similar to this. If you don't recognize this, it is puzzling why int doesn't get a lifetime too.
// `lvl` doesn't need a lifetime because it's not a reference (`&`). Only references need lifetimes.
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It's not only references: struct Foo<'a> { ... } would be fn foo<'a>(x: Foo<'a>).
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| ## Lifetime Elision | ||
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| Earlier, we mentioned 'lifetime elision,' a feature of Rust which allows you to | ||
| not write lifetime annotations in certain circumstances. All references must |
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Maybe this could be "all references have a lifetime" or something else that emphasises that it is an inherent property of references.
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r? @huonw |
| fn foo<'a>() -> &'a str | ||
| ``` | ||
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| This one has both: |
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Well, it has one, that is used in both input and output position.
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both meaning and input and output lifetime, even though they are the same one. Is it worth an extra few words?
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Fixes #19662.