ID fields can sometimes be generated with ForeignRefs

For example:

ExplicitPrimaryKey sql=explicit_primary_key
    Id Text

produces an EntityDef of

    EntityDef
        { entityHaskell = EntityNameHS{unEntityNameHS = "ExplicitPrimaryKey"}
        , entityDB = EntityNameDB{unEntityNameDB = "explicit_primary_key"}
        , entityId =
            EntityIdField
                ( FieldDef
                    { fieldHaskell = FieldNameHS{unFieldNameHS = "Id"}
                    , fieldDB = FieldNameDB{unFieldNameDB = "id"}
                    , fieldType = FTTypeCon Nothing "Text"
                    , fieldSqlType = SqlString
                    , fieldAttrs = [FieldAttrOther "Text"]
                    , fieldStrict = False
                    , fieldReference =
                        ForeignRef (EntityNameHS{unEntityNameHS = "ExplicitPrimaryKey"})
                    , fieldCascade = FieldCascade{fcOnUpdate = Nothing, fcOnDelete = Nothing}
                    , fieldComments = Nothing
                    , fieldGenerated = Nothing
                    , fieldIsImplicitIdColumn = True
                    }
                )
        , [...]
        }

I would expect fieldReference = NoReference here - it doesn't really make sense for an entity's ID field to be a reference to itself.

Start by locating the code that generates EntityDef values for implicit ID fields and reproducing the ExplicitPrimaryKey example from the issue. Trace why the ID receives a ForeignRef to its own entity; done means the generated fieldReference is NoReference for this case.