[Haskell-cafe] [] == []

[Rustom Mody]

On Tue, Mar 10, 2015 at 6:54 PM, Brandon Allbery <allbery.b at gmail.com>
wrote:

> On Tue, Mar 10, 2015 at 9:18 AM, Rustom Mody <rustompmody at gmail.com>
> wrote:
>
>> On Tue, Mar 10, 2015 at 2:03 PM, Brandon Allbery <allbery.b at gmail.com>
>> wrote:
>>
>>> On Mon, Mar 9, 2015 at 10:33 PM, Rustom Mody <rustompmody at gmail.com>
>>> wrote:
>>>
>>>> 1. Which instance of == is being used?
>>>> 2. Is there some option controlling this behavior?
>>>>
>>>
>>> The instance being used is (), and it's controlled by
>>> -XExtendedDefaultRules.
>>>
>>>
>>> https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/interactive-evaluation.html#extended-default-rules
>>>
>>
>> Thats what I first thought
>> Tried starting ghci with  -XNoExtendedDefaultRules
>> but it does not turn it off
>>
>
> Looks like -X only affects compiler flags:
>
>
>     Prelude> :showi language
>     base language is: Haskell2010
>     with the following modifiers:
>       -XNoMonomorphismRestriction
>       -XNoDatatypeContexts
>       -XNondecreasingIndentation
>       -XExtendedDefaultRules
>
> Probably need to use :seti inside of ghci, or in a .ghci / ghci.ini file.
>

Ok that did it -- Thanks Brandon.

Also thanks Taylor for the exact pointer to the divergence between ghc and
ghci semantics
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