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explain place alignment
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RalfJung committed Aug 22, 2023
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* Data races.
* Accessing (loading from or storing to) a place that is [dangling] or unaligned.
* Accessing (loading from or storing to) a place that is [dangling] or [unaligned].
* Performing a place projection that violates the requirements of [in-bounds
pointer arithmetic][offset]. A place projection is a [field
expression][project-field], a [tuple index expression][project-tuple], or an
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The span of bytes a pointer or reference "points to" is determined by the pointer value and the size of the pointee type (using `size_of_val`).

### Unaligned places
[unaligned]: #unaligned-places

The alignment requirement of a place is computed based on the entire place expression since the last `*` (if any).
If the place was computed via `(*ptr).field.field`, then the final place is considered aligned only if `ptr` is aligned *according to its type*.

### Dangling pointers
[dangling]: #dangling-pointers

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