Adding System.Collections.Immutable into the mix

[SamuelBerger]

Hi Florian,
We are also hit by the "Could not load type 'System.Runtime.CompilerServices.IsReadOnlyAttribute' from assembly System.Collections.Immutable ..." when trying to upgrade to .NET 7.

I observed, that the System.Runtime.CompilerServices.IsReadOnlyAttribute is emitted to F# struct only when System.Collections.Immutable package is referenced in the project.

I have tried to build with the latest preview 7.0.200-preview.22628.1 as well, same result. But I am not sure, if the fix is already included there.
You've said I was able to compile my [repro] with the local compiler and the test now passes.

Could you try it again with this PR?

Cheers sam

[nojaf]

Hi Sam, I've changed my struct to a class in my production code instead.
In the grand scheme of things, the change was insignificant to my code and I could go on with my life.
System.Collections.Immutable was not a direct dependency so I had no control over that.

[SamuelBerger]

I see :)
My only workaround would be implementing those structs in C#.
I will create an issue in the F# compiler then.
Thanks for replying and all the content you create! 🙏

[nojaf]

Out of curiosity, where can you download 7.0.200-preview.22628.1?

[SamuelBerger]

Installing latest Visual Studio preview. I use Rider and VS remains only an SDK installer for me :)

[nojaf]

You could also try the 7.0.300 preview from https://github.com/dotnet/installer#table