The called function should be payable if you send value and the value you send should be less than your current balance. WITH NON-Payable functions

Question

I have the following functions

function balance() public view returns(uint152) {
        return uint152(IERC20(token).balanceOf(address(this)));
    }
    
    function balance1() public view returns(IERC20) {
        return IERC20(token);
    }

The first one throws the error mentioned in the title, but the second one works just fine. Can you please help me understand, why does the function needs to be payable when I'm just checking the balance of a certain token. Thank you.

Answer 1

balance() => you are doing an unnecessary (and wrong) conversion, since function balanceOf() from an ERC20 contract will return a uint256.

balance1() => in your example, this is actually returning the token address, not its balance.

So you probably should update your functions to:

contract Test {
    function balance() public view returns(uint256) {
        return IERC20(token).balanceOf(address(this));
    }
    
    function contractAddress() public pure returns(IERC20) {
        return IERC20(token);
    }
}