Cannot compile .NETCoreApp,v6.0 by FSharpChecker.Compile

Cannot compile .NETCoreApp,v6.0 by FSharpChecker.Compile

With the latest FSharp.Compiler.Service (41.0.6) and net6.0 I cannot compile any async code with --targetprofile:netcore.

If the solution to this problem exists then this issue is a question. I desperately look for an answer. Otherwise this issue is a bug report because it is not possible compile or use some typical F# code.

Please find attached a project that compiles two libraries Test1.dll and Test2.dll from Test1.fs and Test2.fs respectively. FCSCompile_221105_0559.zip

Just run

dotnet run

Test1 compiles fine and creates Test1.dll ~ .NETCoreApp,Version=v3.1 (according to ILSpy).

Test2 fails to compile:

The module/namespace 'System' from compilation unit 'netstandard' did not contain the namespace, module or type 'IAsyncDisposable'

Presumably it has to be compiled as .NETCoreApp,Version=v6.0 but it is not clear how.

F# compiler options do not have anything suitable (or I miss it).

[vzarytovskii]

Update: with recent net7.0 and FSharp.Compiler.Service 42.7.101 the issue is the same.

As far as I understand, there is no known way to specify the TargetFramework. So some default is used. But why is the default .NETCoreApp,Version=v3.1 in the described scenario? Per https://dotnet.microsoft.com/en-us/platform/support/policy its support is coming to an end next month.

I can’t wrap my head around it quite yet, need to think about it a bit more.

[nightroman]

@T-Gro This does not help. Namely if in the attached project and code I use @"-r:C:\...\bin\Debug\net6.0\FSharp.Core.dll" (see below) then the problem is the same. The explicitly referenced FSharp.Core.dll is correct, .NETStandard,Version=v2.1

// Test2: it fails to compile ~ The module/namespace 'System' from compilation unit 'netstandard' did not contain the namespace, module or type 'IAsyncDisposable'
// Presumably it has to be compiled as .NETCoreApp,Version=v6.0 but it is not clear how

let args2 = [|
    "fsc.exe"
    @"-r:C:\...\bin\Debug\net6.0\FSharp.Core.dll"
    "--targetprofile:netcore"
    "--target:library"
    $"-o:{root}/Test2.dll"
    $"{root}/Test2.fs"
|]

let res2 =
    checker.Compile args2
    |> Async.RunSynchronously