Remix: el gas requerido excede la asignación o siempre falla la transacción

Entorno: Remix web IDE, red de prueba Ropsten.

A continuación se muestra mi contrato:

pragma solidity ^0.4.16;

contract TokenERC20 {
    // Public variables of the token
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    uint256 public totalSupply;

    // This creates an array with all balances
    mapping (address => uint256) public balanceOf;

    // This generates a public event on the blockchain that will notify clients
    event Transfer(address indexed from, address indexed to, uint256 value);

    function TokenERC20(
        uint256 initialSupply,
        string tokenName,
        string tokenSymbol
    ) public {
        totalSupply = initialSupply * 10 ** uint256(decimals);  // Update total supply with the decimal amount
        balanceOf[msg.sender] = totalSupply;                // Give the creator all initial tokens
        name = tokenName;                                   // Set the name for display purposes
        symbol = tokenSymbol;                               // Set the symbol for display purposes
    }

    /**
     * Internal transfer, only can be called by this contract
     */
    function _transfer(address _from, address _to, uint _value) internal {
        // Prevent transfer to 0x0 address. Use burn() instead
        require(_to != 0x0);
        // Check if the sender has enough
        require(balanceOf[_from] >= _value);
        // Check for overflows
        require(balanceOf[_to] + _value >= balanceOf[_to]);
        // Save this for an assertion in the future
        uint previousBalances = balanceOf[_from] + balanceOf[_to];
        // Subtract from the sender
        balanceOf[_from] -= _value;
        // Add the same to the recipient
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
        // Asserts are used to use static analysis to find bugs in your code. They should never fail
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
    }


    function transfer(address _to, uint256 _value) public returns (bool success) {
        _transfer(msg.sender, _to, _value);
        return true;
    }

}

Es muy básico, puedo implementar este contrato con éxito. Pero cuando llamo a esta función de transferencia, recibí la advertencia:

Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending? 
Error: gas required exceeds allowance or always failing transaction at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:1401895 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:931969 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:350331 at o (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:368562) at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353161 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:350331 at c (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353437) at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353475 at Ht (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:362844) at Object.<anonymous> (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353564) at e.value (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:932884) at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:932451 at n (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:368506) at o (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:368584) at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353161 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:932417 at n (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:368506) at o (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:368584) at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353161 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:932790 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353971 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:350331 at c (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353437) at s (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353359) at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353161 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:353951 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:932672 at chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:931109 at i (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/background.js:1:1070338)

Si trato de ejecutar esta función a la fuerza, la transacción fallará. Alguien sabe qué le pasa a mi código, ¡gracias chicos!