Function pointer_origin_param_local_inner 

fn pointer_origin_param_local_inner<'tcx>(
    tcx: TyCtxt<'tcx>,
    caller: DefId,
    place: &PlaceKey,
    forward: &ForwardVisitResult<'tcx>,
    seen: &mut HashSet<PlaceKey>,
) -> Option<usize>

Recursively follows local values and call summaries to recover pointer provenance.