doc: Clarify the lifetime returned by Box::leak
#52189
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
`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`.
|
r? @bluss (rust_highfive has picked a reviewer for you, use r? to override) |
rust-highfive
added
the
S-waiting-on-review
|
Ping from triage, @bluss: This PR requires your review. |
pietroalbini
added
the
A-docs
|
Ping from triage! This PR needs a review, can @bluss or someone else from @rust-lang/docs review this? |
| /// `&'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`. |
There was a problem hiding this comment.
isn't this a must, not a may?
There was a problem hiding this comment.
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.
|
@bors r+ Thanks! |
|
📌 Commit 6aeeda7 has been approved by |
bors
added
S-waiting-on-bors
bors
added a commit
that referenced
this pull request
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`.
|
☀️ Test successful - status-appveyor, status-travis |
# for free
to join this conversation on GitHub.
Already have an account?
# to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
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.