lifetimes2.rs

pub struct OpenRadioContext<'a, 'b:'a> {
    _context: PhantomData<&'b Context>,
    usb_context: Box<Context>,
    device_handle: DeviceHandle<'a>,
}

impl <'a, 'b> Drop for OpenRadioContext<'a, 'b> {
    fn drop(&mut self) {
        self.device_handle.release_interface(0).unwrap();
    }
}

impl <'a, 'b: 'a> OpenRadioContext<'a, 'b> {
    fn open() -> OpenRadioContext<'a, 'b> {
        let ctx: Box<Context> = Box::new(Context::new().unwrap()); // Has lifetime b' but Rust doesn't know that
        let ctx2: &'b Context = &ctx;
        let mut handle = ctx2.open_device_with_vid_pid(0x1915, 0x7777).and_then(|mut hndl: DeviceHandle<'a>| {
            hndl.reset();
            hndl.set_active_configuration(1).unwrap();
            hndl.claim_interface(0).unwrap();
            Option::Some(hndl)
        }).unwrap();
        OpenRadioContext {
            _context: PhantomData,
            usb_context: ctx,
            device_handle: handle,
        }
    }
}

----

error: `ctx` does not live long enough
  --> src/lib.rs:74:34
   |
74 |         let ctx2: &'b Context = &ctx;
   |                                  ^^^ does not live long enough
...
86 |     }
   |     - borrowed value only lives until here
   |
note: borrowed value must be valid for the lifetime 'b as defined on the body at 72:42...
  --> src/lib.rs:72:43
   |
72 |     fn open() -> OpenRadioContext<'a, 'b> {
   |                                           ^

error: aborting due to previous error