Lack of checks by missing-zero-check detector in parent contract's constructor.

[dev1644]

missing-zero-check detector doesn't seem to check the arguments for constructor of parent contracts. Even if the parent contract's constructor has zero-access checks & the child contract is using the same variable, it's gets flagged.

e.g. For this test contract,

pragma solidity 0.7.6;

abstract contract Ownable {
    address public owner1;
    address public owner2;

    constructor (address __owner1, address __owner2) {
        require(__owner1 != address(0), "Zero");
        owner1 = __owner1;
        owner2 = __owner2;
    }
}

contract ABC is Ownable {

    address public owner3;

    constructor(address _owner1, address _owner2) Ownable(_owner1, _owner2) {
        owner3 = _owner1;
    }
}

Slither output:

ABC.constructor(address,address)._owner1 (contracts/ABC.sol#21) lacks a zero-check on :
                - owner3 = _owner1 (contracts/ABC.sol#22)
Reference: https://github.com/crytic/slither/wiki/Detector-Documentation#missing-zero-address-validation
. analyzed (2 contracts with 103 detectors), 1 result(s) found

• Even though _owner1 is checked for zero address, it gets flagged by the detector.
• _owner2 doesn't have the check but is ignored by the detector.