How to initiate SpreadAllocated storage including other contract reference?

Question

use erc20::Erc20Ref;
use ink_storage::traits::SpreadAllocate;

#[ink(storage)]
#[derive(SpreadAllocate)]
pub struct Bridge {
    map: ink_storage::Mapping<AccountId, u32>,
    token: Erc20Ref,
}

impl Bridge {
    #[ink(constructor)]
    pub fn new(token: Erc20Ref) -> Self {
        ink_lang::utils::initialize_contract(|contract: &mut Self| {
            contract.token = token;
        })
    }
}

the problem is: the trait ink_storage::traits::SpreadAllocate is not implemented for erc20::Erc20Ref

Are there ways to make it properly without manual implementation of SpreadAllocate trait?

Answer 1

Duplicate of that question.

The answer is no. The workaround is to implement it manually=)