how to fix Ambiguous occurrence error in Haskell

Question

I have wrote one function which has a signature of

sort :: [Int] -> [Int]

which gives me an error of

Ambiguous occurrence ‘sort’

I know there is already a built-in function called sort in

import Data.List

How can i fix this issue while keeping the same type signature?

Answer 1

You can try

import Data.List hiding (sort)

This will prevent Data.List.sort from being imported, leaving you free to define your own function called sort.

If you want to be able to use Data.List.sort in addition to your own, also add the line

import qualified Data.List

or

import qualified Data.List as L

This allows you to to access the library function as Data.List.sort or L.sort, respectively.

Answer 2

Try qualifying the name:

module Foo where

import Data.List as L

Then, to refer to the library sort, use L.sort. For the user-defined sort, use Foo.sort instead.