TypeError: Invalid type for argument in function call. Invalid implicit conversion from bytes calldata to uint256 requested. proposals.push(msg.data);

pragma solidity ^0.4.17;

    contract FantasyLeague {
        // Define addresses of league members
        address public member;
        // Hold data of proposed number
        uint[] public proposals;

        // Deploy contract
        constructor() public {
            member = msg.sender;

        // Propose new team number
        function proposeNumber (uint) public payable {
            require(msg.value > .01 ether);

        // Retrieve List of current proposals
        function getProposals () public view returns (uint[]) {
            return proposals;

2 Answers 2


It's unclear what you're trying to do, but you probably just want this:

function proposeNumber(uint number) public payable {
    require(msg.value > .01 ether);
  • Thanks smarx! I now realize I also need to ensure users don't vote with multiple account addresses which can be generated quite easily. What would be the easiest way to ensure that? Through a modifier? Or perhaps through some delegate function?
    – kefa
    Commented Aug 12, 2018 at 20:30
  • I'm unclear on your requirement. Can you define what a "user" is and how it differs from an "account?"
    – user19510
    Commented Aug 12, 2018 at 20:56
  • A user is someone in our league who needs to cast a vote. If a user is utilizing Meta Mask to cast their vote, can't they produce multiple "addresses" on their Meta Mask account and theoretically have multiple votes by the same person?
    – kefa
    Commented Aug 13, 2018 at 16:45
  • Yes. It's impossible from within a smart contract to know something about the identity of a human. You'd need some external vetting process (like whitelisting one address per human who presents an ID to you in person or something like that).
    – user19510
    Commented Aug 13, 2018 at 16:47

since msg.data is bytes and here proposals is array of uint256 you need convert bytes to uint

 function proposeNumber () public payable {
           uint temp;
           require(msg.value > .01 ether);
           // bytes calldata is not implicitly convertible to expected type storage pointer so use memory
            bytes memory b = msg.data;
            for(uint i=0;i<b.length;i++){
            temp = temp + uint(b[i])*(2**(8*(b.length-(i+1))));

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