rust - Lifetime of reference to boxed value does not live long enough -

the following code doesn't compile:

use std::borrow::borrow;  struct inner<'a> {     v: vec<&'a u8>, }  struct foo<'a> {     inner: inner<'a>,     derp: box<u8>, }  impl<'a> foo<'a> {     fn new() -> foo<'a> {         let mut e = foo {             inner: inner { v: vec![] },             derp: box::new(128),         };         e.inner.v.push(&*e.derp);          return e;     }      fn derp(&mut self) {         println!("{:?}", self.inner.v);     } }  fn main() {     let mut f = foo::new();      f.derp(); } 

i following error:

error[e0597]: `*e.derp` not live long enough   --> src/main.rs:18:25    | 18 |         e.inner.v.push(&*e.derp);    |                         ^^^^^^^ not live long enough ... 21 |     }    |     - borrowed value lives until here    | note: borrowed value must valid lifetime 'a defined on impl @ 12:1...   --> src/main.rs:12:1    | 12 | / impl<'a> foo<'a> { 13 | |     fn new() -> foo<'a> { 14 | |         let mut e = foo { 15 | |             inner: inner { v: vec![] }, ...  | 25 | |     } 26 | | }    | |_^ 

i think value inside of box live long 'a since member of foo, has lifetime.

i wondered if move of foo @ end of new function confusing it, if tried append in derp. different error:

error[e0495]: cannot infer appropriate lifetime borrow expression due conflicting requirements   --> main.rs:20:27    | 20 |         self.inner.v.push(& *self.derp);    |                           ^^^^^^^^^^ 

which gives me no indication of lifetime compiler thinks boxed value has.

i think though value inside of box live long 'a since member of foo has lifetime.

it possible assign new box derp member, @ point old box dropped , lifetime of value in ends.

i think trying impossible in safe rust: cross-references between struct members not supported. comes regularly question, it's not available in language.

• how initialize struct fields reference each other
• why can't store value , reference value in same struct?

you can use rc work around this, perhaps in combination refcell.