VisualFSharp VS Roslyn

If you're interested, you could further raise this on F# discord server or in https://github.com/dotnet/fsharp, F# is effectively a community-managed language so if there's a particular change you'd like to see, there is a high chance you can just make it happen if you have time to see it through.

Thanks for the tips! I had thought there were still some other gotchas with AOT and F# but it looks like the list is smaller than last time I looked. https://github.com/dotnet/fsharp/issues/13398

Nullness checking

Not quite accurate with the Parallel example. Don Syme is explicit that applicative `async` should not implicitly start work in the thread pool (https://github.com/dotnet/fsharp/issues/10301#issuecomment-7...).

There's docs about how the compiler generally does optimizations here: https://github.com/dotnet/fsharp/blob/main/docs/optimizations.md

You should add your +1 to https://github.com/dotnet/fsharp/issues/8764, which would add a syntax like #r: project ... to FSI.

So when people are mad about MS and F#, one can see here that: https://github.com/dotnet/fsharp/graphs/contributors MS does a lot more for F# then people being all pessimistic in reddit.

F# AOT feature tracking

C# has COMEFROM, too: https://github.com/dotnet/roslyn/blob/main/docs/features/int...

they make it cumbersome to use by hand, but not impossible

>> It is not a compiler error. It is never a compiler error (2017)

No, not always true. Even in modern compilers -- as matured and as modern as VS 2022-- you would still get bug.

I found one[0]. In my case it's easy to tell it's a compiler bug because the program just can't compile properly. But it's also not easy to reproduce, which just proves how well tested compilers usually are.

0: https://github.com/dotnet/roslyn/issues/74872

MSBuildLocator for .NET Framework can only search for MSBuild 15, 16, 17 (Visual Studio 2017, 2019, 2022). So, if a user has a fairly old project and is using Visual Studio 2015, Roslyn won't be able to find a suitable MSBuild. Even if the project is fully built on the system, Roslyn simply won't work. We've reported this issue on GitHub. To cut a long story short, the devs don't prioritize it, citing that VS 2015 and earlier versions are just outdated. However, it turns out that if the user has the .NET SDK, Roslyn starts using a backup plan. If you have a .NET Framework legacy project, Roslyn will try to use BuildHost for .NET Core. Most of the time, this works fine, but issues can occur if there's something that isn't supported by MSBuild for .NET Core. You'll see this in the description of the third issue.

C# extension works well and uses Roslyn Language Server that is part[0] of the Roslyn (C# compiler) - this is what the base C# extension[1] uses. Both of these are licensed under MIT.

The only closed-source component is 'vsdbg' which is Visual Studio's debugger shipped as a component that the extension uses. It, however, can be replaced with Samsung's 'NetCoreDbg' by using the extension fork[2].

[0]: https://github.com/dotnet/roslyn/tree/main/src/LanguageServe...

[1]: https://github.com/dotnet/vscode-csharp

[2]: https://github.com/muhammadsammy/free-vscode-csharp

see also: https://github.com/dotnet/roslyn/pull/7850

The .NET runtime[1] and C# compiler[2] are both pretty easy to embed.

[1] https://learn.microsoft.com/en-us/dotnet/core/tutorials/netc...

[2] https://github.com/dotnet/roslyn/blob/main/docs/wiki/Scripti...

The C# compiler has an MIT license and is available on GitHub, which is about as FOSS as it gets.

https://github.com/dotnet/roslyn

My understanding is that the .NET team is working toward this with Interceptors: https://github.com/dotnet/roslyn/blob/main/docs/features/int...

.NET is a little smarter about switch code generation these days: https://github.com/dotnet/roslyn/pull/66081