[OM] Missing Verifier on Class Op return Type

[seldridge]

Currently, there is no verifier that the type of an om.class correctly matches the new om.class.fields terminator.

Consider the following:

om.class @A(%arg: i1) {
  om.class.fields %arg : i1
}

Currently, circt-opt will accept this. However, the type should be verified to be:

om.class @A(%arg: i1) -> (a: i1) {
  om.class.fields %arg : i1
}

[mikeurbach]

Thanks for filing this. There is also #7078, but that is more about adding back a local verifier on object.field. I think this one is more about a local verifier on class.fields, which we should also have. @leonardt can you please take a look?

[seldridge]

Fixed via: e080112