use 5.0 sdk

[brettfo]

Now that dotnet/runtime#40864 is fixed, we can directly consume the 5.0 SDK.

tl;dr

VS 16.8 is now required to build.

Long version

The 5.0 SDK requires MSBuild 16.8 which requires VS 16.8. The internal VMs have been updated.

Local run of .\build.cmd -testVs passes.

Internal build has passed.

[cartermp]

It's annoying to install a preview, especially since it revs much faster than stable.

Luckily, it won't remain that way for long.

[brettfo]

CI runs are failing on the assembly verifier calling AssemblyName.GetAssemblyName() on D:\a\1\s\artifacts\bin\Microsoft.FSharp.Compiler\Release\netcoreapp3.1\fsc.exe. Same issue can be reproduced locally with a C# console app trying to read that file.

I'll experiment a bit to see what's happening.

[KevinRansom]

@brettfo the PE file clrheader is corrupt, I will see if I can figure out why.

[auduchinok]

VS 16.8 Preview is now required to build.

Do I get it right that it's only about the CI and VisualFSharp.sln, so FSharp.sln and FSharp.Compiler.Service.sln are going to be fine with dotnet build when #10151 is fixed?

[KevinRansom]

@brettfo,

This is probably not a good thing, main branch needs to build on the RTM release ... this will require the preview release.

##vsotask.logissue type=error Developer Command Prompt for VS 16.0 is not recent enough. Please upgrade to 16.8 or build from a plain CMD window

[brettfo]

@KevinRansom this change will require 16.8 preview to be installed on developer boxes and it should work on CI; I modeled global.json on Roslyn which also requires 16.8. Is the issue that the fsc.exe included in the MSBuild package is too old (and as a result writes a bad header)? If so we'll need to talk to @jaredpar about updating the F# in the xcopy-msbuild package (at least I think he's the one that updates that.)

[cartermp]

Do I get it right that it's only about the CI and VisualFSharp.sln, so FSharp.sln and FSharp.Compiler.Service.sln are going to be fine with dotnet build when #10151 is fixed?

If VS is not used, then yes. It would require the .NET 5 SDK though.

[jaredpar]

f so we'll need to talk to @jaredpar about updating the F# in the xcopy-msbuild package (at least I think he's the one that updates that.)

The most recent updates should support 16.8.