Using 'RemoveUnreachableTypes' option in HC 12 breaks BCP (and other graphql IDEs)

[Andrej-Peplinski]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Using .ModifyOptions(options => options.RemoveUnreachableTypes = true); breaks Banana Pop Cake (and Insomnia).
I have been able to reproduce the issue using HC v.12.5 and v.12.6

Steps to reproduce

1. Check out the Schema First demo example (from here)
2. Optionally remove the [UsePaging] attribute from the Query.GetPersons method.
   This is to ensure that the generated schema does not include any auto-generated Int field
   
3. Add .ModifyOptions(options => options.RemoveUnreachableTypes = true); to Program.cs
   
4. Reproduce the problem by starting the demo application an hopping over to BCP. You should see a spinning doughnut as the fetched schema is not readable. Then open the [F12] Browser tools and see the following error message
   

Relevant log output

No response

Additional Context?

Digging a bit deeper to the root cause.

First look at the sdl and find that there is only one Int field (in the stream directive):

Second find the 'introspection_phase_2' query in the Network tab of the Browser tools:

Inspect the response in a tool like e.g. VS Code and you will see that effectively no Int SCALAR type has been defined. However, it's being used in the scalar directive...

Third repeat the same steps but this time without the options.RemoveUnreachableTypes option....

Product

Hot Chocolate

Version

12.6