# \[Idea\] Two lifetimes on unique references

**URL:** https://internals.rust-lang.org/t/idea-two-lifetimes-on-unique-references/10613
**Category:** language design
**Created:** [July 22, 2019, 1:44pm UTC](https://internals.rust-lang.org/t/idea-two-lifetimes-on-unique-references/10613 "2019-07-22T13:44:25Z")
**Posts on this page:** 1
**Showing post:** 5

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### Author: ![Ixrec](https://sea2.discourse-cdn.com/flex002/user_avatar/internals.rust-lang.org/ixrec/32/6754_2.png) [@Ixrec](https://internals.rust-lang.org/u/Ixrec)
#### Post date: [July 22, 2019, 2:11pm UTC](https://internals.rust-lang.org/t/idea-two-lifetimes-on-unique-references/10613/5 "2019-07-22T14:11:59Z")

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I think this old post by @nikomatsakis is still a fairly accurate summary of where we're at with this sort of idea:

> [@Relaxing the borrow checker for fn (&mut self) -\> &T](https://internals.rust-lang.org/t/relaxing-the-borrow-checker-for-fn-mut-self-t/3256/16):
>
> So this issue comes up repeatedly. My take is this: In the current model, @kvijayan’s claims are not quite correct, but the issue he identifies is annoying, and it’d be nice to have a better solution. First let me explain the model as I see it. I think this is quite similar to what @eddyb has been saying, though there are a lot of comments here and I’ve not parsed them all with 100% care. I think it’s easiest to think of the current model in terms of permissions. So when you do the borrow you g…

Probably the biggest change since he wrote that is simply that we have NLL now 🥳, but "a proposal for a Rust memory model" is still a ways off (see [GitHub - rust-lang/unsafe-code-guidelines: Forum for discussion about what unsafe code can and can't do](https://github.com/rust-lang/unsafe-code-guidelines))

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