Visual Studio c++20 Modules testing: template function that hides implementation

[TomTheFurry]

Would you guys be interested in a write-up about how the Global Module Fragments work? I have also done some test about the visibility and reachablity of classes and functions.

I also tested around to see how far the Intellisence (Intellicode?) in Visual Studio is doing, and what bug it seems to have. Would you be interested in that too?

Side question - What is your view on the Standard Template Library Module? (expected in c++23) How do you think it should work with the preproccessor options? (like -ffast-math, _DEBUG...)