Error:
browser/IERC20.sol:4:53: Warning: This declaration shadows an existing declaration. function totalSupply() public constant returns (uint256 totalSupply);
browser/IERC20.sol:4:5: The shadowed declaration is here: function totalSupply() public constant returns (uint256 totalSupply);
IERC20.sol
pragma solidity ^0.4.17;
interface IERC20 {
function totalSupply() public constant returns (uint256 totalSupply);
function balanceOf(address _owner) public constant returns (uint256 balance);
function transfer(address _to, uint256 _value) public returns (bool success);
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
function approve(address _spender, uint256 _value) public returns (bool success);
function allowance(address _owner, address _spender) public constant returns (uint256 remaining);
event Transfer(address indexed _from, address indexed _to, uint256 _value);
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}
INDToken.sol
pragma solidity ^0.4.11;
import './IERC20.sol';
contract INDToken is IERC20 {
    uint public constant _totalSupply = 1000000;
    string public constant symbol = "IND";
    string public constant name = "Indonesia Token";
    uint8 public constant decimals = 3;
    mapping(address => uint256) balances;
    mapping(address => mapping(address => uint256)) allowed;
    function INDToken() public {
        balances[msg.sender] = _totalSupply;
    }
    function totalSupply() public constant returns (uint256 totalSupply){
        return _totalSupply;
    }
    function balanceOf(address _owner) public constant returns (uint256 balance){
        return balances[_owner];
    }
    function transfer(address _to, uint256 _value) public returns (bool success){
        require(
            balances[msg.sender] >= _value
            && _value > 0
        );
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        Transfer(msg.sender, _to, _value);
        return true;
    }
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success){
        require(
            allowed[_from][msg.sender] >= _value
            && balances[_from] >= _value
            && _value > 0
        );
        balances[_from] -= _value;
        balances[_to] += _value;
        allowed[_from][msg.sender] -= _value;
        Transfer(_from, _to, _value);
        return true;
    }
    function approve(address _spender, uint256 _value) public returns (bool success) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining){
        return allowed[_owner][_spender];
    }
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}