StrawberryShake v13 not generating source for schema with inheritance

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I have an existing HC/SS v12 based solution with an inheritance structure in it. SSv12 had no problem generating code from this model, but SSv13 complains twice about the base class, saying that it's been defined already. I'm attaching a minimized and anonymized schema file that illustrates the problem. In this schema, "Exercise" and "Survey" both inherit the common base class "Activity".

Running "dotnet graphql generate" yields the output provided below.

Steps to reproduce

1. Run the SSv13 graphql "generate" function against the provided schema.

Relevant log output

PM> dotnet graphql generate
Generate C# Clients started.
Generate Include started.
Generate Include completed in 366 ms
error HC0065: The name `Activity` was already registered by another type.
Generate IncludeClient started.
Generate IncludeClient completed in 110 ms
error HC0065: The name `Activity` was already registered by another type.

Additional Context?

https://gist.github.com/MelGrubb/e8ec4ca7509269505de4216cd34eb091

Product

Strawberry Shake

Version

13.0.0-preview.88

Start with the minimized schema linked in the issue and run dotnet graphql generate against it to reproduce the duplicate Activity HC0065 errors. Trace the Strawberry Shake v13 generation path for inherited types; done means the schema generates successfully without reporting Activity as already registered.