QDir::exists is not doing what was documented

In the Qt documentation, for example in http://doc.qt.io/qt-5/qdir.html#exists it's written:

QDir::exists(const QString & name) const

Returns true if the file called name exists; otherwise returns false. [...]

however, this code

QString path="/etc/hosts";
if (QDir(path).exists())
    qDebug() << path << "exists.";
else
    qDebug() << path << "does not exist.";

writes "does not exist", although the file exists.

The documentation about QDir::exists in Qt4 and Qt5 should be changed ?

Thanks!