rem: void mergeComp( Todo* const dest, const Todo* const src) { dest->setCompleted( src->isCompleted() ); }
add: static void mergeComp( Todo* const dest, const Todo* const src) { dest->setCompleted( src->isCompleted() ); }
context:     void mergeComp( Todo* const dest, const Todo* const src)    {        dest->setCompleted( src->isCompleted() );    }