Access violation when clearing recent files in File menu

[Gumball2415]

issue originally from new_wub on ft.o discord server

version: Dn0.5.1.0 release

steps to reproduce:

• File -> Recent Files -> Clear
• confirm prompt
• unhandled exception C0000005 occurs

[Gumball2415]

this bug has existed since Dn0.5.0.2, with the addition of the Export JSON option in the File menu.

Dn-FamiTracker/Source/FamiTracker.cpp

Lines 442 to 458 in 680c772

	void CFamiTrackerApp::OnRecentFilesClear() // // //
	{
	int confirm = AfxMessageBox(IDS_CLEAR_RECENTS, MB_YESNO | MB_ICONEXCLAMATION | MB_DEFBUTTON2);
	if (confirm == IDNO) {
	return;
	} else if (confirm != IDYES) {
	throw std::runtime_error("Recent Files Clear message box returned invalid value");
	}
	SAFE_RELEASE(m_pRecentFileList);
	m_pRecentFileList = new CRecentFileList(0, _T("Recent File List"), _T("File%d"), MAX_RECENT_FILES);
	auto pMenu = m_pMainWnd->GetMenu()->GetSubMenu(0)->GetSubMenu(14);
	for (int i = 0; i < MAX_RECENT_FILES; ++i)
	pMenu->RemoveMenu(ID_FILE_MRU_FILE1 + i, MF_BYCOMMAND);
	pMenu->AppendMenu(MF_STRING, ID_FILE_MRU_FILE1, _T("(File)"));
	}

the program indexes into the Recent Files submenu with hardcoded numbers. thus, when it tries to assign the pointer to 14th item in the Files menu to pMenu (the separator before Recent Files), it returns nullptr, and crashes on the member function RemoveMenu().