Roslyn: Migrate Roslyn packages to use System.Composition instead of Microsoft.Composition

[prafullbhosale]

Having a dependency on Microsoft.Composition requires the project to have

<PackageTargetFallback>portable-net45+win8</PackageTargetFallback>

(imports in the project.json world)

System.Composition is the new package for MEF2 and is a replacement for Microsoft.Composition
https://www.nuget.org/packages/System.Composition

cc @srivatsn @davidfowl

[Pilchie]

Can we do this soon so that there is time to react in other parts of the stack?

[pranavkm]

Any idea when this would be addressed?

[jmarolf]

@pranavkm there is a surprising amount of work that needs to be changed on the VS side, but I hope to get this done this week.

[JunTaoLuo]

👀

[JunTaoLuo]

Any updates on this?

[jmarolf]

fixed with https://github.com/dotnet/roslyn/pull/19754

[prafullbhosale]

@jmarolf any ideas on when this planned for release and with what version?

cc @mlorbetske

[jmarolf]

@prafullbhosale I believe the first nuget packages to have this change will be 2.3-beta3 . You can try out the packages from myget today to verify.