Updated FCS to latest

[ncave]

• Updated FCS to latest (bd66d54).

[ncave]

@nojaf
I had to downgrade some dependencies to make the latest FCS work on .NET 6.0 as well.
Otherwise it would only work on .NET 7.0/8.0.

[nojaf]

Thanks for this @ncave!

[MangelMaxime]

As the tests are green, it looks good to me.

Should we keep the PR open and wait for the official .NET 8 release?

Or because everything seems good, should it be included in the next Fable release?

[nojaf]

It might be interesting to have an alpha of this if that is possible.
@abonie has implemented dotnet/fsharp#14640 and I believe Fable was a good use-case for this.

People could play around with this ahead of the official release.

[ncave]

@MangelMaxime Feel free to merge before next release, if you're ok with it.

[nojaf]

Hi @ncave

I had to downgrade some dependencies to make the latest FCS work on .NET 6.0 as well.

Would it be possible to do this as well for the other projects in FSharp.Compiler.Service.sln.
I'm no longer able to build the solution in your fork:

C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
 Warning As Error: Detected package downgrade: System.Collections.Immutable from 7.0.0 to 6.0.0. Reference the package
directly from the project to select a different version.  [C:\Users\nojaf\Projects\fsharp\FSharp.Compiler.Service.sln]
C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
  FSharp.Compiler.Service.Tests -> FSharp.Test.Utilities -> FSharp.Build -> Microsoft.Build.Tasks.Core 17.7.0-preview-2
3217-02 -> System.Collections.Immutable (>= 7.0.0)  [C:\Users\nojaf\Projects\fsharp\FSharp.Compiler.Service.sln]
C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
  FSharp.Compiler.Service.Tests -> FSharp.Test.Utilities -> System.Collections.Immutable (>= 6.0.0) [C:\Users\nojaf\Pro
jects\fsharp\FSharp.Compiler.Service.sln]
C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
 Warning As Error: Detected package downgrade: System.Reflection.Metadata from 7.0.0 to 6.0.1. Reference the package di
rectly from the project to select a different version.  [C:\Users\nojaf\Projects\fsharp\FSharp.Compiler.Service.sln]
C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
  FSharp.Compiler.Service.Tests -> FSharp.Test.Utilities -> FSharp.Build -> Microsoft.Build.Tasks.Core 17.7.0-preview-2
3217-02 -> System.Reflection.Metadata (>= 7.0.0)  [C:\Users\nojaf\Projects\fsharp\FSharp.Compiler.Service.sln]
C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
  FSharp.Compiler.Service.Tests -> FSharp.Test.Utilities -> System.Reflection.Metadata (>= 6.0.1) [C:\Users\nojaf\Proje
cts\fsharp\FSharp.Compiler.Service.sln]
C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
 Warning As Error: Detected package downgrade: System.Collections.Immutable from 7.0.0 to 6.0.0. Reference the package
directly from the project to select a different version.  [C:\Users\nojaf\Projects\fsharp\FSharp.Compiler.Service.sln]
C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
  FSharp.Compiler.Service.Tests -> FSharp.Test.Utilities -> FSharp.Build -> Microsoft.Build.Utilities.Core 17.7.0-previ
ew-23217-02 -> System.Collections.Immutable (>= 7.0.0)  [C:\Users\nojaf\Projects\fsharp\FSharp.Compiler.Service.sln]
C:\Users\nojaf\Projects\fsharp\tests\FSharp.Compiler.Service.Tests\FSharp.Compiler.Service.Tests.fsproj : error NU1605:
  FSharp.Compiler.Service.Tests -> FSharp.Test.Utilities -> System.Collections.Immutable (>= 6.0.0) [C:\Users\nojaf\Pro
jects\fsharp\FSharp.Compiler.Service.sln]

I'm still able to build the compiler project.

[ncave]

@nojaf

I'm no longer able to build the solution in your fork

Are you trying to build it with .NET 6.0? I haven't tried building those other projects in the solution.

I don't think you can build FCS with .NET 6.0, or at least not anymore, without making some changes.
It has to be build with .NET 8.0, or at least .NET 7.0.

What I meant above was that dependency package downgrade makes those errors disappear when the package is consumed on .NET 6.0, i.e. makes it possible to consume the FSharp.Compiler.Service binary from projects built with .NET 6.0 (like Fable), which otherwise would hang at tcImports.GetImportedAssemblies() because of the "Detected package downgrade" errors you posted above.

Technically you don't need to build anything else besides FSharp.Compiler.Service in this fork, but there is a test project in the fcs folder to make sure it works, if you need it. There are build instructions here.

I hope that clarifies it a bit, let me know if it doesn't.
I wish we could soon switch Fable to .NET 8.0, but I guess we're stuck with .NET 6.0 to support for a while, so until then, a package version downgrade seems the easiest thing to make it work on .NET 6.0.

[nojaf]

Thanks, I'm building using SDK dotnet 8 RC 2.

Building that test project didn't work for me, but I don't think that is related to the downgrade:

 ~#@❯  dotnet run -c Release --project fcs/fcs-test
C:\Users\nojaf\Projects\fsharp\fcs\fcs-test\fcs-test.fsproj : warning NU1603: fcs-test depends on Fable.Core (>= 4.1.0)
 but Fable.Core 4.1.0 was not found. An approximate best match of Fable.Core 4.1.1 was resolved.
C:\Users\nojaf\Projects\fsharp\fcs\fcs-test\fcs-test.fsproj : error NU1101: Unable to find package Fable.Import.Browser
. No packages exist with this id in source(s): C:\Program Files\dotnet\sdk\8.0.100-rc.2.23502.2\FSharp\library-packs, h
ttps://pkgs.dev.azure.com/azure-public/vside/_packaging/vs-impl-archived/nuget/v3/index.json, https://pkgs.dev.azure.co
m/azure-public/vside/_packaging/vs-impl/nuget/v3/index.json, https://pkgs.dev.azure.com/azure-public/vside/_packaging/v
ssdk-archived/nuget/v3/index.json, https://pkgs.dev.azure.com/azure-public/vside/_packaging/vssdk/nuget/v3/index.json,
https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-eng/nuget/v3/index.json, https://pkgs.dev.azure.com/dnceng/p
ublic/_packaging/dotnet-public/nuget/v3/index.json, https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nu
get/v3/index.json, https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet7/nuget/v3/index.json, https://pkgs.dev.az
ure.com/dnceng/public/_packaging/dotnet8-transport/nuget/v3/index.json, https://pkgs.dev.azure.com/dnceng/public/_packa
ging/dotnet8/nuget/v3/index.json

The build failed. Fix the build errors and run again.

[ncave]

@nojaf Strange, could be some nuget cache thing. It restores and builds fine for me on WSL2 with .NET 8.0 RC2. Anyway, if you have to, you can reference a newer Fable.Core to make it work.

<PackageReference Include="Fable.Core" Version="4.1.1" />

Actually, looks like the latest version is 4.2.0. Doesn't matter, they should all work.

[ncave]

@nojaf Found another mention of the FCS package downgrade issue.

[vzarytovskii]

I am still confused with the issue, FCS is ns2.0/ns2.1, all the dependencies should as well be ns2.0/ns2.1, I don't see why do those errors appear.

[ncave]

@vzarytovskii Some sort of packaging issue? I'm not really sure, but it should be easy to reproduce, even with a C# project.