[Question] How to support older versions of .net-SDK when authoring a source-generator?

[earloc]

Hey folks.

I´m authoring a neat little source-generator over at https://github.com/earloc/TypealizR, where I´m doing some minor code-analysis over C# using Microsoft.CodeAnalysis.CSharp.

Recently, I wittnessed one of my github-actions to fail the build on an agent with .net6 . The build broke once I updated Microsoft.CodeAnalysis.CSharp to 4.4.0, so I donwgraded to 4.3.0 in order to get things working again.

Then I tried to just bundle the assembly as suggested here, but doing so then breaks whenever I build on an agent with .net7, giving the following error during compilation:

Unhandled Exception: System.InvalidCastException: 
[A]Microsoft.CodeAnalysis.CSharp.Syntax.CompilationUnitSyntax cannot be cast to 
[B]Microsoft.CodeAnalysis.CSharp.Syntax.CompilationUnitSyntax. 
Type A originates from 'Microsoft.CodeAnalysis.CSharp, Version=4.4.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' in the context 'Default' at location 'C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Current\Bin\Roslyn\Microsoft.CodeAnalysis.CSharp.dll'. 
Type B originates from 'Microsoft.CodeAnalysis.CSharp, Version=4.4.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' in the context 'LoadFrom' at location 'C:\Users\[USERNAME]\.nuget\packages\typealizr\0.8.3\analyzers\dotnet\cs\Microsoft.CodeAnalysis.CSharp.dll'.

To reproduce, just reference the (unlisted) version 0.8.3 of my TypealizR-package in a fresh console-project on a machine with .net7-sdk

Is there something I can do to still support older sdks, other than just downgrading Microsoft.CodeAnalysis.CSharp?
I guess to support even older sdk´s (or good old full-fx), I would even need to downgrade to an even lesser version, right?

#107 looks kind of an enabler for my scenario, but wasn´t exactly sure.

[earloc]

Ahh, I guess this is related to dotnet/sdk#20355