I prefer no blank lines. If you feel like you need one, write a line comment instead describing the next section.
Whitespace gives readers subtle information about the structure of a function before they read any of it. Its a powerful tool. Dismissing or - worse - deleting whitespace wholesale sounds profoundly misguided to me.
Why make code harder to read? Where's the benefit to your approach? I can't see any.
https://doc.rust-lang.org/src/core/slice/mod.rs.html#2786-28...
The function is pretty short - 40 lines including comments. Despite how short the function is, it still uses whitespace to separate and group adjacent lines of code. Personally, I find the code more readable like this. Indentation makes syntactic blocks obvious (the while loop and if statement). But there are also conceptual groupings between lines that mean nothing to the compiler, but are semantically meaningful to humans. I can tell at a glance that the comment about safety is most associated with that one line below the comment. And so on.
I think this code would be worse if we deleted the whitespace. How would you improve this code?
At a minimum, the blank lines implicitly scope the comments that sit above connected code blocks. Those comments - especially the comment about safety - would be harder to understand and audit without its context being so clear.
And again, can you name any benefit to removing all the blank lines? If we can both read the code easily with some empty lines to space it out, that seems like the best option.