Can bypass repr(packed) checking by using --cap-lints
#26
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C-bug
Category: related to a bug.
C-upstream-bug
Category: This is a bug of compiler or dependencies (the fix may require action in the upstream)
I-unsound
A soundness hole (worst kind of bug), see: https://en.wikipedia.org/wiki/Soundness
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55: Prepare for removal of safe_packed_borrows lint r=taiki-e a=taiki-e pin-project-lite is using `safe_packed_borrows` lint for checking `repr(packed)` types. (See taiki-e/pin-project#34 for more) As described in #26, lint-based tricks aren't perfect, but they're much better than nothing. `safe_packed_borrows` is planned to be removed in favor of `unaligned_references` (rust-lang/rust#82525), so I would like to switch to `unaligned_references`. (However, actually, enable both lint as `unaligned_references` does not exist in older compilers.) Co-authored-by: Taiki Endo <[email protected]>
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NOTE: pin-project (not lite) is not affected by this issue. see taiki-e/pin-project#34 (comment) for more.EDIT: see taiki-e/pin-project#342 for pin-project (not lite)
Currently, pin-project-lite uses
safe_packed_borrowlint to check that the struct is notrepr(packed). Unfortunately,safe_packed_borrowis lint and you can use the rustc's--cap-lintsflag to lower the lint cap level: https://godbolt.org/z/jEf1fGThe current pin-project-lite generates almost the same code as pin-project, but does not have the equivalent of the
repr(packed)checking that proc-macro(pin-project) does during expansion. (Since the proc-macro-attribute used on the struct expand later than declarative macro used for the struct, a complete fix for the problem is probably impossible untilsafe_packed_borrowgets a hard error.)The text was updated successfully, but these errors were encountered: