[DSMan195276]

I agree, but IMO it's not all that clear to me that this is guaranteed. The documentation for the default layout pretty clearly says[0]:

> There are no guarantees of data layout made by this representation.

So that being the case, there's not really anything stopping them from introducing a situation where an unaligned field in a struct is created in the future. Of course I can't imagine why they would do that, but then maybe my imagination just isn't good enough. I think the author's point here (which is a good one in my opinion) is that when writing `unsafe` you're not supposed to rely on stuff that seems like it should be true, you're supposed to rely on stuff that's guaranteed to always be true, which with Rust isn't all that clearly defined.

[0]: https://doc.rust-lang.org/reference/type-layout.html#the-def...

[Ericson2314]

If struct fields weren't aligned, then safe Rust would be completely and utterly broken. And really obviously so.

This isn't just a matter of things "seeming". It is quite literally an implication of Safe Rust works => field offsets must be aligned. There is no other way for safe Rust to be safe, other than alignment not mattering at all because all accesses are careful to pessimistically not rely on it.

I am sorry, but this hypothesis is just completely outside the Overton Window.

[DSMan195276]

The thing is, C has an actual standard and people get bit making the same kinds of assumptions on things not stated. You may very well be right that there's no way this will ever happen, but then it also doesn't appear to be guaranteed. They literally say they make no guarantees about the data layout, but you're assuming there is a guarantee about the data layout :P

Maybe this time it works out, but there's plenty of other cases where things are not so clear cut.