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contracts...extcodecopy_in_constructor.sol

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

contract One {
    function getOne() external pure returns (uint) {
        return 1;
    }
}

contract Two {
    uint256 public copiedChunk;

    constructor(bytes32 chunk) {
        copiedChunk = uint256(chunk)+1;
    }
}

contract Main {
    One one = new One();
    Two two;

    constructor() {
        bytes memory chunk = new bytes(0);
        address one_addr = address(one);

        assembly {
            extcodecopy(one_addr, chunk, 0, 32)
        }

        two = new Two(bytes32(chunk));
    }

    function getChunk() external view returns (uint256) {
        return two.copiedChunk();
    }
}