QT5 moc cannot parse __declspec instruction

[Kelloggs]

I am currently migrating a project from QT4 to QT5. I am now facing a problem that has not been there when using QT4 regarding dllexport and dllimport. Whenever declaring __declspec(..) for a method within the slots scope, the moc is returning a parse error. I have created a small, artificial example.

qt5test.h
@
#ifndef QT5TEST2_H
#define QT5TEST2_H

#include <QtWidgets/QMainWindow>
#include "ui_qt5test2.h"

class qt5test2 : public QMainWindow
{
Q_OBJECT

public:
qt5test2(QWidget *parent = 0);
~qt5test2();

public slots:
__declspec(dllexport) void highlightSomething();

private:
Ui::qt5test2Class ui;
};

#endif // QT5TEST2_H
@

qt5test2.cpp
@
#include "qt5test2.h"

qt5test2::qt5test2(QWidget *parent)
: QMainWindow(parent)
{
ui.setupUi(this);
}

qt5test2::~qt5test2()
{

}

void qt5test2::highlightSomething()
{

}
@

Output
@
1>------ Rebuild All started: Project: qt5test2, Configuration: Debug Win32 ------
1> Moc'ing qt5test2.h...
1> C:\Users\jcornelis\documents\qt5test\qt5test2\qt5test2\qt5test2.h(16): Parse error at ")"
@

Am i doing something wrong? I am a bit confused, since the project compiled flawlessly against Qt4.8.