allow references to point to invalid values - #2335
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| r[undefined.validity.reference-box] | ||
| * A reference or [`Box<T>`] must be aligned and non-null, it cannot be [dangling], and it must point to a valid value (in case of dynamically sized types, using the actual dynamic type of the pointee as determined by the [metadata]). Note that the last point (about pointing to a valid value) remains a subject of some debate. | ||
| * A reference or [`Box<T>`] must be aligned and non-null, and cannot be [dangling]. |
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This is missing the requirement that the pointee type must be inhabited (and there is a bit of subtlety around what exactly "inhabited" means).
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#2337 supersedes this PR. |
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Per @rust-lang/opsem FCP in rust-lang/unsafe-code-guidelines#414 (comment), partially unblocking rust-lang/rust#161452. This would mean invalid references are downgraded to being library UB (but invalid values are still lang UB).