‘show’ is not a (visible) method of class ‘Show’

I think I am trying to do something relatively innocent, but relude is
not having it. Here is a minimal example.

My Cabal file:

cabal-version:    3.4
name:               dev
Version:            1.0
build-type:         Simple
author:             Henry Laxen
maintainer:         nadine.and.henry@pobox.com

library
  default-language:    GHC2024
  hs-source-dirs:      .
  build-depends:       base, relude
  exposed-modules:     Dev
  default-extensions:
  mixins:   base hiding (Prelude)
          , relude (Relude as Prelude)
          , relude

my Code:

module Dev where
import Prelude hiding (show)

newtype A = A Int

instance Show A where
  show (A x) = "A " <> show x

when i compile it, I get:

/home/henry/haskell/dev/Dev.hs:7:3-6: error: [GHC-54721] …
‘show’ is not a (visible) method of class ‘Show’

Compilation failed.

Now you may ask, why do I want this. Elsewhere I have a large data
type that contains

connection :: Network.WebSocket.Connection
I wanted to make a Show instance of this so I defined

newtype Conn = Conn Network.WebSocket.Connection

instance Show Conn where
  show _ = "Conn"

to wrap the Network.WebSocket.Connection
which led me to this problem

I did the same thing with plain Prelude (no relude mixin) and it worked as expected.

[tomjaguarpaw]

I agree it's weird. Sorry, I have no idea why this is.

[vrom911]

Hi @henrylaxen , I see that you are hiding show:

import Prelude hiding (show)

why is that?

[nekowinston]

The line

import Prelude hiding (show)

seemingly isn't needed, I made a tiny repo to reproduce it: https://github.com/nekowinston/relude-issue-481

The second commit (nekowinston/relude-issue-481@5e1cdbf) works around the issue, but I don't really understand how it works, given how I don't even specify instance BasePrelude.Show A where.

I'm on a recent nixpkgs-unstable with GHC 9.10.3 if that matters.