I really can't figure out whats wrong with this function, its probably something stupid but I can't see it. Thanks.

function duplicatefinder(mapping exists, uint256 intermediate, uint256[] expandedValues) internal pure {
        if(exists[intermediate] == false){
            expandedValues[i] = intermediate;
            exists[intermediate] = true;
        } else {
            intermediate += 1 % 20;
            duplicatefinder(exists, intermediate, expandedValues);

1 Answer 1


Well you cannot pass whole mapping as a function parameter. To work with mappings you should already have them declared and then in the function you can pass the key mapping key, something like this:

mapping (uint256 => bool) exists;

function duplicatefinder(uint256 intermediate, uint256[] expandedValues) internal pure {
    if (exists[intermediate] == false) {
        // do something ...

If you need to pass dynamic list of data then you can maybe use array as function parameter.

  • Thank you, I have fixed my problem with your advice! Jan 13, 2022 at 14:17
  • Happy to help. You can accept my answer as correct so others having the same issue can recognize the solution. Jan 13, 2022 at 14:19

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