Gas estimation failed in Remix

Question

Can't really use the transfer function as it is written. It assumes the owner uses it. So made a new function for the "minting" function for the faucet to use. Not sure why the compiler message is so cryptic.

totalSupply_ = totalSupply_.add(_amount);
balances[_to] = balances[_to].add(_amount);
emit Mint(_to, _amount);
emit Transfer(address(0), _to, _amount);

Trying to create a Faucet for my ERC-20 Token, and getting a "Gas Estimation Failed" when running my dripToken function which looks like this (UPDATED):

function dripToken() public {
  require(faucetStatus);
  if(!checkStatus(msg.sender)) revert();
  tokenInstance.updateSupply(oneToken);
  updateStatus(msg.sender, oneMinute);
  tokenInstance.transfer(msg.sender, oneToken);
}

I have narrowed it down to the line with the transfer call which causes the error. I now deploy my ERC-20 Token and pass that into the faucet contract on the following way:

constructor(string _fname, address _tokenInstance) public {
  tokenInstance = MyToken(_tokenInstance);
  faucetName = _fname;
  faucetStatus = true;

  emit FaucetOn(faucetStatus);
}

My Token transfer function is from https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC20/StandardToken.sol I just noticed I get a compiler warning on the transfer function which hints at the problem, but I don't understand why (yet). Here is the warning:

Gas requirement of function StandardToken.transfer(address,uint256) high: infinite. If the gas requirement of a function is higher than the block gas limit, it cannot be executed. Please avoid loops in your functions or actions that modify large areas of storage (this includes clearing or copying arrays in storage)

function transfer(address _to, uint256 _value) public returns (bool) {
  require(_value <= balances[msg.sender]);
  require(_to != address(0));

  balances[msg.sender] = balances[msg.sender].sub(_value);
  balances[_to] = balances[_to].add(_value);
  emit Transfer(msg.sender, _to, _value);
  return true;
}

I create my Token in the following way. I now initialize it with a small supply.

contract MyToken is StandardToken {
  string public name;                   
  uint8 public decimals;                
  string public symbol;  

  constructor() public {  
    StandardToken.balances[msg.sender] = 1000000000000000000;
    StandardToken.totalSupply_ = 1000000000000000000;                        
    name = "My Token";                             
    decimals = 18; 
    symbol = "MY";      
  }
}

Posted my code on google drive: https://drive.google.com/open?id=1EvKEVhD8bR2oKS2W1XNRQpTqVbieUcmC

Answer 1

See top of OP for answer. I think it was the require block that failed. Not sure why the compiler is so cryptic about it.

Answer 2

You must specify the address that is calling transfer. For example, if the you are trying to transfer an ERC20 token, the code would be as follows:

ERC20TokenAddress.transfer(msg.sender, oneToken);

Without the leading address, the EVM doesn't know what is being transferred.