QFileInfo.Size() may return a different size for some crafted filename.

(First, sorry if i assign wrong Component).

The bug happened on Qt Core 5.15.2 (my company application on multiple platform Windows/Linux/Mac), and Qt 6.4.2 using Qt creator for reproduce the bug:

(Qt 6.4.2 (x86_64-little_endian-llp64 shared (dynamic) release build; by MSVC 2019) on "windows"

• On both Windows and Linux, when a file have "\u00FFFF" or "\u0FFFFF" in its name, no matter it is the first/ only character or between other characters, size() always return 0 for the file, despite the real size of it.

reproduce:

step 1: renaming file with "\u0ffff" in name
step 2: querying the file size
step 3: size() return 0.

• On Windows, when the file have ".lnk" extension, despite it is not a real Shortcut (symlink) file, size() always return 0 for the file, despite the real size of it.  

reproduce:

step 1: renaming file with ".lnk" extension
step 2: querying the file size
step 3: size() return 0.

I know that this function will return the symlink's destination file size, but at here it's a valid file not a symlink, here i think it is a error

Reproduce code, in Qt Creator

#include <QCoreApplication>
#include <QString>
#include <QFileInfo>
#include <QTextStream>
#include <iostream>int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QTextStream outp(stdout);
    QTextStream inp(stdin);
    QString str;
    str= inp.readLine();
    outp<<"\n path: \n";
    outp.flush();
    QFileInfo file(str);
    outp<<file.absoluteFilePath();
    outp.flush();
    outp<<"\nsize: \n";
    outp<<file.size();
    outp.flush();
    return a.exec();
} 

(Because my company does not allow use of private account, so i have to create this account for bug reporting. Please cc itsthanhpham@gmail.com for further reply. Thank you.)