Hi all,

Does anyone know why this code:

module Language.P4.UtilTest where

import Language.P4.Util (mkShow)

data Dummy = Bogus Char
| Nonsense Int

$(mkShow ''Dummy)

is producing this error:

Davids-Air-2:P4 dbanas$ stack ghc -- UtilTest.hs -ddump-splices
[1 of 1] Compiling Language.P4.UtilTest ( UtilTest.hs, UtilTest.o )
UtilTest.hs:24:3-16: Splicing declarations
mkShow ''Dummy
======>
instance Show Dummy where
show (Bogus x) = show x
show (Nonsense x) = show x

UtilTest.hs:24:3: error:
Conflicting definitions for ‘show’
Bound at: UtilTest.hs:24:3-16
UtilTest.hs:24:3-16
|
24 | $(mkShow ''Dummy)
| ^^^^^^^^^^^^^^

The TH splice expansion looks correct to me.

If I comment out the second constructor (Nonsense Int), the code compiles without error.

Thanks,

-db