Confusing note about "all struct fields are already assigned" when some fields are private

Code

#![allow(unused)]

mod mem {
    pub struct ProvenanceFrag<Provenance> {
        provenance: Provenance,
        position: usize,
    }
}

use crate::mem::*;

fn mkthing<Provenance>(p: Provenance) {
    let _f = ProvenanceFrag { provenance: p, pos: 0.into() };
}

Current output

error[E0560]: struct `mem::ProvenanceFrag<Provenance>` has no field named `pos`
  --> src/lib.rs:13:46
   |
13 |     let _f = ProvenanceFrag { provenance: p, pos: 0.into() };
   |                                              ^^^ `mem::ProvenanceFrag<_>` does not have this field
   |
   = note: all struct fields are already assigned

Desired output

Rationale and extra context

Not entirely sure what the best output is here, but it definitely shouldn't say that all fields are already assigned when that is simply wrong.

Other cases

Rust Version

current nightly

Anything else?

No response