Windows compiler error: Score::fileInfo() method doesn't exist

in file.cpp, compiler threw error for these two "name = ..." lines in this #ifdef :

{syntaxhighlighter C}
#ifdef Q_OS_WIN
if (QSysInfo::WindowsVersion == QSysInfo::WV_XP) {
if (!cs->isMaster())
name = QString("%1/%2-%3").arg(saveDirectory).arg(cs->masterScore()->fileInfo()->completeBaseName()).arg(createDefaultFileName(cs->fileInfo()->completeBaseName()));
else
name = QString("%1/%2").arg(saveDirectory).arg(cs->fileInfo()->completeBaseName());
}
else
#endif
{/syntaxhighlighter}

because fileInfo() is not a property of Score, but is only a property of MasterScore. For some reaon I can't explain, I didn't have any compiler errors a couple days ago when also building on same window smachine. Got it to run now by simply inserting ->masterScore() before the fileInfo(), so now looks like:

{syntaxhighlighter C}
#ifdef Q_OS_WIN
if (QSysInfo::WindowsVersion == QSysInfo::WV_XP) {
if (!cs->isMaster())
name = QString("%1/%2-%3").arg(saveDirectory).arg(cs->masterScore()->fileInfo()->completeBaseName()).arg(createDefaultFileName(cs->masterScore()->fileInfo()->completeBaseName()));
else
name = QString("%1/%2").arg(saveDirectory).arg(cs->masterScore()->fileInfo()->completeBaseName());
}
else
#endif
{/syntaxhighlighter}

Any explainations?