fix: Error on infinitely recursive types

[jfecher]

Description

Problem*

Resolves #7173

Summary*

Adds a check during monomorphization that we never create any recursive types which are likely to be infinitely sized.

Additional Context

I also added a file for monomorphization tests so we don't have to keep creating a full test_program for these monomorphization errors.

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[michaeljklein]

What about a test for Foo<Bar<()>> where both Foo and Bar are enums? Or if that case works, what about if Bar is an alias or struct-wrapper of Foo?

Naming nit: are these recursive types or simply nested enums? I'd expect the error to be more similar to the nested slices error.

[jfecher]

Naming nit: are these recursive types or simply nested enums? I'd expect the error to be more similar to the nested slices error.

They're.. semi-recursive enums. Nested enums like Option<Abc> are allowed and in tests already. Structs or enums that reference themselves recursively internally will panic during monomorphization before this PR even if the recursion terminates. I'll add some more tests.

[jfecher]

@michaeljklein Added more tests