Stop applying dereferenceable(n) to return types
#149948
Open
+13
−8
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
rustbot
added
S-waiting-on-author
rustbot
added
the
S-waiting-on-review
Collaborator
rustbot
removed
the
S-waiting-on-author
WaffleLapkin
commented
Dec 13, 2025
| // potentially self-referential types (see | ||
| // <https://github.com/rust-lang/unsafe-code-guidelines/issues/381>). If LLVM had a way | ||
| // to say "dereferenceable on entry" we could use it here. | ||
| attrs.pointee_size = match kind { |
Member
Author
There was a problem hiding this comment.
drive-by: I really dislike how we track dereferenceable as pointee_size: Size, this should imo really be dereferenceable: Option<NonZeroU64>, or something.
Member
There was a problem hiding this comment.
Yeah this entire code could benefit from a large-scale refactor.^^
Member
Author
There was a problem hiding this comment.
I might or might not do something about it ^^"
Member
Collaborator
bors
added
S-waiting-on-bors
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 participants
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Outdated suggestions cannot be applied.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.
It looks like the semantics of
dereferenceable(n)on return types is "dereferenceable until the end of the program", which is not sound for how we were using it. See dereferenceable on return type zulip thread.cc @rust-lang/opsem @nikic