`<filesystem>`: `exists()` fails with "Access denied" for certain type of symlinks

Describe the bug

We use std::filesystem::exists to check existence of paths on the system. Since few days we started to see an error where this function would fail with Access Denied. Unfortunately I could not get a fully reproducible example but I am gonna describe what I noticed.

This is the logged error

Exists D:\some_path\WebKit.framework = 0 with ec 5 and msg Access is denied.

This is the list of paths inside some_path

d-----        11/15/2024   4:51 AM                _SceneKit_SwiftUI.framework
d-----        11/15/2024   4:51 AM                _StoreKit_SwiftUI.framework
d-----        11/15/2024   4:51 AM                _SwiftData_SwiftUI.framework
d-----        11/15/2024   4:51 AM                _Translation_SwiftUI.framework
-a---l        11/15/2024   4:51 AM              0 AuthenticationServices.framework
-a---l        11/15/2024   4:51 AM              0 JavaScriptCore.framework
-a---l        11/15/2024   4:51 AM              0 SafariServices.framework
-a---l        11/15/2024   4:51 AM              0 WebKit.framework

The function fails on all the paths having the a and l bit on while it succeeds on the others.
Permissions should not be the problem: I tried with different users and with all of them I can read the files using powershell (with a simple ls).

Other things worth mentioning: these are symlinks that point to other symlinks

$ stat Modules
  File: Modules -> Versions/Current/Modules
  Size: 24              Blocks: 0          IO Block: 65536  symbolic link

$ stat Versions/Current/Modules
  File: Versions/Current/Modules
  Size: 0               Blocks: 0          IO Block: 65536  directory

$ stat Versions/Current
  File: Versions/Current -> A
  Size: 1               Blocks: 0          IO Block: 65536  symbolic link

$ stat Versions/A/
  File: Versions/A/
  Size: 0               Blocks: 0          IO Block: 65536  directory

again, I tried to repro by re-building a folder structure of this type but I couldn't reproduce the error

Any advice?

Start at std::filesystem::exists and investigate the Windows handling of the described framework-style symlinks, especially links that point through another symlink. First try to reproduce the Access Denied error with the shown chain and compare it with PowerShell access. Done means the failure is understood and corrected, with the behavior covered by a regression test.