doc: Clarify the lifetime returned by Box::leak
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`Box::leak` mentions that it can return a `'static` reference, but it wasn't immediately clear to me why it doesn't always do so. This is because of the `T: 'a` constraint needed to form a valid reference, and in general we want to be more flexible than requiring `T: 'static`. This patch tries to clarify the relationship between `T` and `'a`.
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| /// `&'a mut T`. Here, the lifetime `'a` may be chosen to be `'static`. | ||
| /// `&'a mut T`. Note that the type `T` must outlive the chosen lifetime | ||
| /// `'a`. If the type has only static references, or none at all, then this | ||
| /// may be chosen to be `'static`. |
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isn't this a must, not a may?
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No, it's variant in the lifetime, so it can be shorter. Only T: 'static can leak as &'static mut T, but it can also leak as any other lifetime.
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@bors r+ Thanks! |
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Jul 24, 2018
doc: Clarify the lifetime returned by `Box::leak` `Box::leak` mentions that it can return a `'static` reference, but it wasn't immediately clear to me why it doesn't always do so. This is because of the `T: 'a` constraint needed to form a valid reference, and in general we want to be more flexible than requiring `T: 'static`. This patch tries to clarify the relationship between `T` and `'a`.
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☀️ Test successful - status-appveyor, status-travis |
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Box::leakmentions that it can return a'staticreference, but itwasn't immediately clear to me why it doesn't always do so. This is
because of the
T: 'aconstraint needed to form a valid reference, andin general we want to be more flexible than requiring
T: 'static.This patch tries to clarify the relationship between
Tand'a.