Nontermination when using datatypeNameModifier with recursive data types

[amiddelk]

Using LTS 9.9 with swagger2-2.1.6 or, alternatively, the current main branch of the repository:
When using the option genericDeclareNamedSchema in combination with recursive data types, the produced schema grows unbounded. Here is a standalone example:

{-# LANGUAGE DeriveGeneric #-}
module Main where

import Data.Proxy
import Data.Swagger
import Data.Swagger.Declare
import GHC.Generics

data SomeTy =
  SomeCon { keyA :: Int, keyB :: Maybe SomeTy }
  deriving (Eq, Show, Generic)

instance ToSchema SomeTy where
  declareNamedSchema = genericDeclareNamedSchema schemaOpts

schemaOpts = defaultSchemaOptions
  { Data.Swagger.datatypeNameModifier = drop 1 }

proxySomeTy :: Proxy SomeTy
proxySomeTy = Proxy

testSomeTy :: NamedSchema
testSomeTy = undeclare $ declareNamedSchema proxySomeTy

main :: IO ()
main = putStrLn (show testSomeTy)

My best guess would be that the transformed name is not taken properly in account when checking for recursion.