Dependent 'main' does not exist

[horHay]

just editing my QT application and after building the error;

:-1: error: dependent 'main' does not exist.

has appeared. Any ideas? New to QT so really no idea about the program etc, here is my main file;
@
#include "widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Widget w;
w.show();

return a.exec();

}
Widget File

#include "widget.h"
#include "ui_widget.h"
#include "shipHandler.h"
#include "navalVessels.h"

Widget::Widget(QWidget *parent) :
QWidget(parent),
ui(new Ui::Widget)
{
ui->setupUi(this);

SDI::shipHandler shipHandler("ships.txt");
sh = shipHandler;
Widget::populateCombo();

}

Widget::~Widget()
{
delete ui;
}

void Widget::populateCombo()
{
for( std::vectorSDI::navalVessels*::const_iterator i = sh.ships.begin(); i != sh.ships.end(); ++i)
{
SDI::navalVessels* ship = *i;
QString qstr = QString::fromStdString(ship->name);
ui->comboBox->addItem(qstr);
}
}
@

[edit: add coding tags @ SGaist]

[SGaist]

Hi and welcome to devnet,

Can you also share your pro file ?