Compile error on develop branch

[MassiminoilTrace]

I am following the compile instruction for the command line.
When I run cmake --build ., it starts compiling and around 48% it gives:

/home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.cpp: In member function ‘virtual void MatrixPin::saveSettings(QSettings&) const’:
/home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.cpp:37:36: error: conversion from ‘const Index’ {aka ‘const long int’} to ‘const QVariant’ is ambiguous
pSettings.setValue( "rows", rows );
^
In file included from /usr/include/qt5/QtCore/qlocale.h:43,
from /usr/include/qt5/QtCore/qtextstream.h:46,
from /usr/include/qt5/QtCore/qdebug.h:49,
from /usr/include/qt5/QtCore/QDebug:1,
from /home/rosto/Scaricati/Fugio/Fugio/include/fugio/pin_control_interface.h:5,
from /home/rosto/Scaricati/Fugio/Fugio/include/fugio/pin_interface.h:10,
from /home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.h:8,
from /home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.cpp:1:
/usr/include/qt5/QtCore/qvariant.h:222:5: note: candidate: ‘QVariant::QVariant(float)’
QVariant(float f);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:221:5: note: candidate: ‘QVariant::QVariant(double)’
QVariant(double d);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:220:5: note: candidate: ‘QVariant::QVariant(bool)’
QVariant(bool b);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:219:5: note: candidate: ‘QVariant::QVariant(qulonglong)’
QVariant(qulonglong ull);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:218:5: note: candidate: ‘QVariant::QVariant(qlonglong)’
QVariant(qlonglong ll);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:217:5: note: candidate: ‘QVariant::QVariant(uint)’
QVariant(uint ui);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:216:5: note: candidate: ‘QVariant::QVariant(int)’
QVariant(int i);
^~~~~~~~
In file included from /usr/include/qt5/QtCore/QSettings:1,
from /home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.cpp:3:
/usr/include/qt5/QtCore/qsettings.h:166:10: note: initializing argument 2 of ‘void QSettings::setValue(const QString&, const QVariant&)’
void setValue(const QString &key, const QVariant &value);
^~~~~~~~
/home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.cpp:38:36: error: conversion from ‘const Index’ {aka ‘const long int’} to ‘const QVariant’ is ambiguous
pSettings.setValue( "cols", cols );
^
In file included from /usr/include/qt5/QtCore/qlocale.h:43,
from /usr/include/qt5/QtCore/qtextstream.h:46,
from /usr/include/qt5/QtCore/qdebug.h:49,
from /usr/include/qt5/QtCore/QDebug:1,
from /home/rosto/Scaricati/Fugio/Fugio/include/fugio/pin_control_interface.h:5,
from /home/rosto/Scaricati/Fugio/Fugio/include/fugio/pin_interface.h:10,
from /home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.h:8,
from /home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.cpp:1:
/usr/include/qt5/QtCore/qvariant.h:222:5: note: candidate: ‘QVariant::QVariant(float)’
QVariant(float f);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:221:5: note: candidate: ‘QVariant::QVariant(double)’
QVariant(double d);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:220:5: note: candidate: ‘QVariant::QVariant(bool)’
QVariant(bool b);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:219:5: note: candidate: ‘QVariant::QVariant(qulonglong)’
QVariant(qulonglong ull);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:218:5: note: candidate: ‘QVariant::QVariant(qlonglong)’
QVariant(qlonglong ll);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:217:5: note: candidate: ‘QVariant::QVariant(uint)’
QVariant(uint ui);
^~~~~~~~
/usr/include/qt5/QtCore/qvariant.h:216:5: note: candidate: ‘QVariant::QVariant(int)’
QVariant(int i);
^~~~~~~~
In file included from /usr/include/qt5/QtCore/QSettings:1,
from /home/rosto/Scaricati/Fugio/Fugio/plugins/Math/matrixpin.cpp:3:
/usr/include/qt5/QtCore/qsettings.h:166:10: note: initializing argument 2 of ‘void QSettings::setValue(const QString&, const QVariant&)’
void setValue(const QString &key, const QVariant &value);
^~~~~~~~
gmake[2]: *** [plugins/Math/CMakeFiles/fugio-math.dir/build.make:289: plugins/Math/CMakeFiles/fugio-math.dir/matrixpin.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:3249: plugins/Math/CMakeFiles/fugio-math.dir/all] Error 2
gmake: *** [Makefile:163: all] Error 2

[MassiminoilTrace]

I think the error has been introduced in one of the last commits.
I have now tried compiling the branch release/3.1.0 and it works fine.

[MassiminoilTrace]

Now it compiles, thank you again!