How to resolve "Invalid type for argument in modifier invocation. Invalid implicit conversion from struct" error?

Question

I want my contract to inherit another contract, the issue is that the contract uses a struct inside its constructor, and I'm not sure how to pass that data type from my contract.

Method 1

Contract I want to inherit:

contract Parent {
    struct CustomType {
        uint x;
        bool y;
        string z;
    }

    constructor(CustomType memory customType) {

    }
}

My contract:

contract Child is Parent{
    struct CustomType {
        uint x;
        bool y;
        string z;
    }

    constructor(CustomType memory customType) Parent(customType) {}
}

The error:

TypeError: Invalid type for argument in modifier invocation. Invalid implicit conversion from struct Child.CustomType memory to struct Parent.CustomType memory requested.

Method 2

Importing the struct into the file and using it also doesn't work:

import {Parent, CustomType} from "./Inherit.sol";

contract Child is Parent{

    constructor(CustomType memory customType) Parent(customType) {}
}

The error:

DeclarationError: Declaration "CustomType" not found in "contracts/Inherit.sol"

Answer 1

When inheriting a contract that uses a custom data type inside its constructor, you must reference that data type in your child contract's constructor.

For example:

contract Parent {
    struct CustomType {
        uint x;
        bool y;
        string z;
    }

    constructor(CustomType memory customType) {}
}

contract Child is Parent{
    constructor(Parent.CustomType memory customType) Parent(customType) {}
}