Warns when using Qt keywords such as emit, slots, signals or foreach.
This check is disabled by default and must be explicitly enabled, since using the above Qt keywords is fine unless you're using 3rdparty headers that also define them, in which case you'll want to use Q_EMIT, Q_SLOTS, Q_SIGNALS or Q_FOREACH instead.
It's also recommended you don't use the Qt keywords in public headers.
This check is mainly useful due to its fixit to automatically convert the keywords to their Q_ variants. Once you've converted all usages, then simply enforce them via CONFIG += no_keywords (qmake) or ADD_DEFINITIONS(-DQT_NO_KEYWORDS) (CMake).