Different AssemblyLoadContext for System.CodeDom types

[drolevar]

I'm trying to port a .NET Framework control to .NET 5 which has a custom CodeDomSerializer.

However I'm facing a very strange issue that all the static types are loaded as a part of "Default" context. All the dynamic types though are loaded as a part of "UserAssemblyLoadContext".

So if I write the following:

CodeDomSerializer baseSerializer = (CodeDomSerializer)manager.GetSerializer(typeof(ControlBase).BaseType, typeof(CodeDomSerializer));
var codeObject = baseSerializer.Serialize(manager, value);

And then

var statements = (CodeStatementCollection)codeObject;

I can also get the following exception:

[A]System.CodeDom.CodeStatementCollection cannot be cast to [B]System.CodeDom.CodeStatementCollection.
Type A originates from 'System.CodeDom, Version=7.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' in the context 'Default' at location 'C:\Users\<username>\.nuget\packages\system.codedom\7.0.0\lib\net6.0\System.CodeDom.dll'.
Type B originates from 'System.CodeDom, Version=7.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' in the context 'Default' at location 'C:\Users\<username>\.nuget\packages\system.codedom\7.0.0\lib\net6.0\System.CodeDom.dll'

Do you have an idea how to resolve the issue?

[KlausLoeffelmann]

In .NET the "same" assembly can be loaded twice into the context, just because the file origin is different. Actually, then the assembly is also considered to be a different version. But this doesn't seem to be the case, here.

Could you try to see, if in the debugger at the point where the assembly is about to be used (the types to be cast), the location shown in the debugger of the context is in fact what's been stated here? And then later, if also the debugger states, that both assemblies came from the same origin?

Maybe @terrajobst has an idea here? Also @Shyam-Gupta FYI.

[terrajobst]

@jaredpar likely knows much more than me in this space

[jaredpar]

Does any of your code use Assembly.LoadFrom? That will result in the Assembly being loaded in the Default instead of Current context. Seen that cause this kind of confusion before.