Comment by loeg

21 hours ago

> For (2), Rust enforces this invariant via the borrow checker by disallowing (at compile-time) a shared slice reference that points to an overlapping mutable slice reference.

At least the last time I cared about this, the borrow checker wouldn't allow mutable and immutable borrows from the same underlying object, even if they did not overlap. (Which is more restrictive, in an obnoxious way.)

6 comments

loeg

Cyph0n 20 hours ago

Do you mean borrows for different fields of a struct? If so, that’s handled today - it’s sometimes called “splitting borrows”: https://doc.rust-lang.org/nomicon/borrow-splitting.html

loeg 20 hours ago
Not exactly -- independent subranges of the same range (as would be relevant to something like memcpy/memmove/strcpy). E.g.,
https://godbolt.org/z/YhGajnhEG
It's mentioned later in the same article you shared above.
- oneshtein 11 hours ago
  
  fn f() { let mut v = vec![1, 2, 3, 4, 5]; let (header, tail) = v.split_at_mut(1); b(&header[0], &mut tail[0]); }
  
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- Cyph0n 20 hours ago
  
  Gotcha. There is a split_at_mut method that splits a mutable slice reference into two. That doesn’t address the problem you had, but I think that’s best you can do with safe Rust.
  
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