情商實例似乎很奇怪

Question

{-# LANGUAGE FlexibleContexts #-} 
{-# LANGUAGE FlexibleInstances #-} 
{-# LANGUAGE GeneralizedNewtypeDeriving #-} 
{-# LANGUAGE GADTs #-} 
{-# LANGUAGE TypeFamilies #-} 
{-# LANGUAGE MultiParamTypeClasses #-} 
{-# LANGUAGE TemplateHaskell #-} 
{-# LANGUAGE QuasiQuotes #-} 
module Main 
    where 

import   Database.Persist.Sql 
import   Database.Persist.TH 

share 
    [mkPersist 
     sqlSettings 
      { mpsGeneric = True 
      , mpsPrefixFields = False 
      , mpsEntityJSON = Just EntityJSON 
           { entityToJSON = 'keyValueEntityToJSON 
           , entityFromJSON = 'keyValueEntityFromJSON 
           } 
      , mpsGenerateLenses = False 
      } 
    , mkMigrate "abc"] 
    [persistLowerCase| 
Test 
    a String 
|] 

main :: IO() 
main = do 
    print $ (toSqlKey 1 :: TestId) /= (toSqlKey 1 :: TestId) 
    print $ (toSqlKey 1 :: TestId) == (toSqlKey 1 :: TestId) 

    print $ (toSqlKey 1 :: TestId) /= (toSqlKey 2 :: TestId) 
    print $ (toSqlKey 1 :: TestId) == (toSqlKey 2 :: TestId) 

在此哈斯克爾程序，我讓mpsGeneric開關，這一方案的結果是：

True 
True 
False 
False 

如果禁用mpsGeneric，結果是：

True 
False 
False 
True 

看來，Eq實例上面的那個壞了。 我測試的程序與

persistent of version 2.2.4.1 
persistent-template of version 2.1.6 

這個「功能」殺了我整整一個下午，當我運行後續代碼：

filter (/= someKey) [key1, key2, key3] 

Answer 1

這是一個錯誤。現在在github上報道：https://github.com/yesodweb/persistent/issues/560