Impossible to insert into a StorageMap within a struct when using a helper function

[bitzoic]

It is currently impossible to insert into a StorageMap that is within a struct if using a helper function.

Within the example contract, you may call storage.my_struct.map_map.insert(0, 0), however if passing the StorageKey<MyStruct>, the StorageKey<StorageMap<u64, u64>> becomes inaccessible.

Example Contract:

contract;

use std::hash::Hash;

pub struct MyStruct {
    my_map: StorageMap<u64, u64>,
}

storage {
    my_struct: MyStruct = MyStruct {
        my_map: StorageMap {},
    },
}

abi MyContract {
    #[storage(read, write)]
    fn write();
}

impl MyContract for Contract {
    #[storage(read, write)]
    fn write() {
        // Possible to insert into map
        storage.my_struct.my_map.insert(1, 1);

        // No longer possible to insert into map
        write(storage.my_struct);
    }
}

// Inserts into a StorageMap
#[storage(read, write)]
pub fn write(struct_key: StorageKey<MyStruct>) {
    let my_struct = struct_key.read();

    // This is now a `StorageMap` and not a `StorageKey<StorageMap>`
    my_struct.my_map.insert(3, 3);
}