Heritage with QLineEdit

[insdo]

Hello. I created an extended class QLineEdit. Apparently it's all right but when I go to instantiate it gives an error: undefined external symbol LINK2019. I put the include right. But I do not know what can be. Could someone help me?

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#ifndef MEUCAMPO_H
#define MEUCAMPO_H

#include <QLineEdit>

class MeuCampo : public QLineEdit
{
Q_OBJECT
public:
explicit MeuCampo(QWidget *parent = 0);

signals:

public slots:

};

#endif // MEUCAMPO_H

#include "meucampo.h"

MeuCampo::MeuCampo(QWidget *parent) :
QLineEdit(parent)
{
}

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