GHC 包冲突 [英] GHC package conflicts

问题描述

我正在尝试使用 GHC 编译以下代码:

I'm trying to compile the following code with GHC:

module Test where

import Maybe
import Prelude hiding (null)
import System.IO

null = ()

main :: IO ()
main = putStrLn "Hello, world!"

如果我只运行 ghc Test.hs，我得到:

If I just run ghc Test.hs, I get:

Could not find module `Maybe'
It is a member of the hidden package `haskell98-2.0.0.1'.

所以我尝试 ghc -package haskell98 Test.hs:

Ambiguous module name `Prelude':
  it was found in multiple packages: base haskell98-2.0.0.1

好像不对，不过我试试ghc -package haskell98 -hide-package base Test.hs:

It doesn't seem right, but I try ghc -package haskell98 -hide-package base Test.hs:

Could not find module `System.IO'
It is a member of the hidden package `base'.
It is a member of the hidden package `haskell2010-1.1.0.1'.

然后我尝试 ghc -package haskell98 -hide-package base -package haskell2010 Test.hs:

Ambiguous module name `Prelude':
  it was found in multiple packages:
  haskell2010-1.1.0.1 haskell98-2.0.0.1

我如何编译这段代码?我使用的是 GHC 7.4.1.

How do I compile this code? I'm using GHC 7.4.1.

推荐答案

导入 Data.Maybe.haskell98 包不再与 base 兼容，因此使用 haskell98 模块只会带来不必要的痛苦.

Import Data.Maybe. The haskell98 package is no longer compatible with base, so using the haskell98 modules brings just unnecessary pain.

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