Fixes name shadowing error at keyFromRecordM for Primary keys

[hw202207]

With a persistent definition like,

Customer
  firstName String
  lastName String
  Primary firstName lastName

the keyFromRecordM was generated like

keyFromRecordM = Just
            (\ Customer {customerFirstName = customerFirstName,
                         customerLastName = customerLastName}
               -> (CustomerKey customerFirstName) customerLastName)

hence the name-shadowing error.

The fixes is simply append index to those variables, like

keyFromRecordM
        = Just
            (\ Customer {customerFirstName = customerFirstName_1,
                         customerLastName = customerLastName_2}
               -> (CustomerKey customerFirstName_1) customerLastName_2)

---

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[hw202207]

Fixes an annoying warning.
Unrelated but simple it's simple enough so I just keep it.
I could revert if you prefer.

[hw202207]

To verify the fixes actually work.

[hw202207]

Just found sort of duplicated with #1494
which looks better (used newName instead of mkName)

[parsonsmatt]

Yeah, let's go with the newName approach - I like the testing/verification changes you made here though. Do you mind folding that PR into this one?

[hw202207]

With the newName, the result looks like this

keyFromRecordM
        = Just
            (\ CompanyUserCamelStyle {companyUserCamelStyleCompanyName = companyUserCamelStyleCompanyName_acxmR,
                                      companyUserCamelStyleUserName = companyUserCamelStyleUserName_acxmS}
               -> (CompanyUserCamelStyleKey
                     companyUserCamelStyleCompanyName_acxmR)
                    companyUserCamelStyleUserName_acxmS)

given definition

mkPersist sqlSettings {mpsCamelCaseCompositeKeySelector = True}
  [persistLowerCase|
    CompanyUserCamelStyle
      companyName Text
      userName Text
      Primary companyName userName
  |]

[parsonsmatt]

Great, thank you!