Ariel Ben-Yehuda

Yes

@kennytm Cool. Could you try to bisect to the specific commit? I might then take a go at investigating it.

> Regression at nightly-2017-04-26 (+43µs): 63c7721...2b4c911 (likely #40123 (LLVM 4.0 Upgrade)) Not much we can do about *that* without a fairly deep investigation. We're about to update to LLVM 5.0...

### NOTE: moved to https://github.com/nikomatsakis/nll-rfc/issues/42 @nikomatsakis had also discovered the following interaction ```Rust fn foo() { let x = RefCell::new(42); let ref_x: &'α RefCell = &x; let inner_ref: Ref

```Rust fn example_box) -> &'a mut u32 { &mut **v } fn main() {} ```

> The first is the handling of `Drop` -- the current rules state that `Drop` requires all data to be valid, unless it is declared as may dangle That's a...

I think the confusing thing here is the difference between this issue and #42 - they are actually separate issues. The root cause here is that (both with NLL and...

> So, @pnkfelix has been working on a writeup and prototype implementation of this idea that we had that we called "dangly paths" That looks like a complicated and subtle...

> Huh? When we return the `&mut` (or anything else non-Copy) that was inside the box, we should be moving it out of the box. But we don't return the...

> The main alternative I would expect is for us to just make Box alone carry the necessary magic here, and just have everything else "break" when rust-lang/rust#31567 is fixed,...