# Make borrow safe earlier
**URL:** https://internals.rust-lang.org/t/make-borrow-safe-earlier/7717
**Category:** language design
**Created:** [June 12, 2018, 12:10am UTC](https://internals.rust-lang.org/t/make-borrow-safe-earlier/7717 "2018-06-12T00:10:18Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@naim](https://internals.rust-lang.org/u/naim)
#### Post date: [June 12, 2018, 12:10am UTC](https://internals.rust-lang.org/t/make-borrow-safe-earlier/7717/1 "2018-06-12T00:10:18Z")
Consider the following code:
```rust
struct A<'a> { dal: &'a mut B, }
struct B { }
impl B {
pub fn get_object(&mut self) -> Option<&str> { Some("Got Object") }
}
impl<'a> A<'a> {
pub fn new(a: &mut B) -> A { A{ dal: a } }
pub fn do_something(&mut self) {
match self.dal.get_object() {
None => {
// this causes E0502 since *self.dal was a mutable borrowed and we are attempting to borrow *self.
// In this case, *self is unusable, although it seems it would be perfectly safe to use...
// Shouldn't the borrow have ended when no valid reference was returned (like within Some(...))?
self.report_error();
},
Some(v) => {
println!("retreived {}", v);
}
}
}
fn report_error(&self) { println!("report some error..."); }
}
fn main() {
let mut t = B{};
let mut x = A::new(&mut t);
x.do_something();
}
```
Shouldn’t it be made safe to borrow `*self` again after it’s previous use is no longer accessible?
Any thought?
---
### Author:  [@Ixrec](https://internals.rust-lang.org/u/Ixrec)
#### Post date: [June 12, 2018, 12:16am UTC](https://internals.rust-lang.org/t/make-borrow-safe-earlier/7717/2 "2018-06-12T00:16:59Z")
I believe this is exactly the sort of code that will become legal with the “non-lexical lifetimes” feature, which is documented at [https://github.com/rust-lang/rfcs/blob/master/text/2094-nll.md](https://github.com/rust-lang/rfcs/blob/master/text/2094-nll.md) and is already implemented on nightly.
---
### Author:  [@cuviper](https://internals.rust-lang.org/u/cuviper)
#### Post date: [June 12, 2018, 12:18am UTC](https://internals.rust-lang.org/t/make-borrow-safe-earlier/7717/3 "2018-06-12T00:18:00Z")
Yes, you can try it on nightly with `#![feature(nll)]` at the top of your crate, and this code is accepted.
---
### Author:  [@system](https://internals.rust-lang.org/u/system)
#### Post date: [March 25, 2019, 8:30am UTC](https://internals.rust-lang.org/t/make-borrow-safe-earlier/7717/4 "2019-03-25T08:30:22Z")
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