Function resolve_projection_from_base_ident 

fn resolve_projection_from_base_ident<'tcx>(
    tcx: TyCtxt<'tcx>,
    base_ident: String,
    fields: Vec<String>,
    base_local: usize,
    base_ty: Ty<'tcx>,
) -> Option<(usize, Vec<(usize, Ty<'tcx>)>, Ty<'tcx>)>