Misunderstanding about why a borrowed value does not live long enough

Question

I am facing an error in Rust and I do not understand why I face it.

I have a custom Reader object that owns a Vec of some IFD objects and one HashMap whose objects are references to some IFDEntry elements owned by the IFD elements inside the first vector:

// `IFD` owns some `IFDEntry`
pub struct IFD {
    pub entries: Vec<IFDEntry>,
    pub next: usize,
}

pub struct Reader<'a, R> {
    inner: R,
    order: Endian,
    ifds: Vec<IFD>, // Reader owns the list of `IFD` here
    entries_map: HashMap<Tag, &'a IFDEntry>,
}

This object defines a new function charging of filling those elements accordin to some std::io::BufRead element. At the end of this function :

let mut map = HashMap::<Tag, &IFDEntry>::new();

// ifds owns the differents values here
let ifds: Vec<IFD> = IFDIterator::new(&mut reader, order, offset as usize).collect();

// We fill the map with references
for ifd in &ifds {
    for entry in &ifd.entries {
        map.insert(entry.tag, entry);
    }
}

// Move from both `map` and `ifds` inside the `Reader`
Ok(Reader {
    inner: reader,
    order: order,
    ifds: ifds,
    entries_map: map,
})

The compiler complains that ifds does not live long enough (line 68 corresponds to the return of Ok(Reader)):

error[E0597]: `ifds` does not live long enough
  --> src/reader.rs:56:21
   |
56 |         for ifd in &ifds {
   |                     ^^^^ borrowed value does not live long enough
...
68 |     }
   |     - borrowed value only lives until here
   |
note: borrowed value must be valid for the lifetime 'a as defined on the impl at 16:6...

From my understanding, ifds is moved inside Reader at the end of the function. So why is it considered not living long enough?

The whole file can be found here: https://github.com/yageek/tiff/blob/develop/src/reader.rs