Request: warn about language extensions that are not used

Peter Verswyvelen

11 Mar 2009 11 Mar '09

12:02 p.m.

When I put {-# OPTIONS_GHC -Wall -Werror #-} in my source file, I don't get compiler (GHC) warnings about redundant language extensions that I enabled. It would be nice if the compiler gave warnings about this, since after refactoring, some language extensions might not be needed anymore, and hence should be removed since fewer language extensions mean more stable and portable code no? What do you think?

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Creighton Hogg

11 Mar 11 Mar

12:16 p.m.

New subject: Request: warn about language extensions that are not used

2009/3/11 Peter Verswyvelen :

...

When I put {-# OPTIONS_GHC -Wall -Werror #-} in my source file, I don't get compiler (GHC) warnings about redundant language extensions that I enabled. It would be nice if the compiler gave warnings about this, since after refactoring, some language extensions might not be needed anymore, and hence should be removed since fewer language extensions mean more stable and portable code no? What do you think?

So you mean something like if you put {-# LANGUAGE GeneralizedNewtypeDeriving #-} in a file, but never do newtype deriving, it would warn you? I have no idea how hard that'd be to implement, but that sounds kind of cool. Useful for both refactoring and when you've inherited old code. Cheers, C

Peter Verswyvelen

12:22 p.m.

New subject: Request: warn about language extensions that are not used

Yes, exactly. Indeed I should have given an example, thanks for doing so, I was too hasty being lazy :) On Wed, Mar 11, 2009 at 5:16 PM, Creighton Hogg wrote:

...

2009/3/11 Peter Verswyvelen :

...
When I put {-# OPTIONS_GHC -Wall -Werror #-} in my source file, I don't get compiler (GHC) warnings about redundant language extensions that I enabled. It would be nice if the compiler gave warnings about this, since after refactoring, some language extensions might not be needed anymore, and hence should be removed since fewer language extensions mean more stable and portable code no? What do you think?

So you mean something like if you put {-# LANGUAGE GeneralizedNewtypeDeriving #-} in a file, but never do newtype deriving, it would warn you?

I have no idea how hard that'd be to implement, but that sounds kind of cool. Useful for both refactoring and when you've inherited old code.

Cheers, C

Peter Verswyvelen

2:05 p.m.

New subject: Request: warn about language extensions that are not used

Okay, I submitted it as a GHC feature request. Thanks for the feedback. On Wed, Mar 11, 2009 at 5:16 PM, Creighton Hogg wrote:

...

2009/3/11 Peter Verswyvelen :

...
When I put {-# OPTIONS_GHC -Wall -Werror #-} in my source file, I don't get compiler (GHC) warnings about redundant language extensions that I enabled. It would be nice if the compiler gave warnings about this, since after refactoring, some language extensions might not be needed anymore, and hence should be removed since fewer language extensions mean more stable and portable code no? What do you think?

So you mean something like if you put {-# LANGUAGE GeneralizedNewtypeDeriving #-} in a file, but never do newtype deriving, it would warn you?

I have no idea how hard that'd be to implement, but that sounds kind of cool. Useful for both refactoring and when you've inherited old code.

Cheers, C

Conal Elliott

12 Mar 12 Mar

10:12 a.m.

New subject: Request: warn about language extensions that are not used

Thanks Peter. I'd love to have this feature also. I go back every so often and try removing each of the extensions listed in my LANGUAGE pragma. Didn't occur to me that the compiler could be doing it for me. Regards, - Conal 2009/3/11 Peter Verswyvelen

...

Okay, I submitted it as a GHC feature request. Thanks for the feedback. On Wed, Mar 11, 2009 at 5:16 PM, Creighton Hogg wrote:

...
2009/3/11 Peter Verswyvelen :

...
When I put {-# OPTIONS_GHC -Wall -Werror #-} in my source file, I don't get compiler (GHC) warnings about redundant language extensions that I enabled. It would be nice if the compiler gave warnings about this, since after refactoring, some language extensions might not be needed anymore, and hence should be removed since fewer language extensions mean more stable and portable code no? What do you think?

So you mean something like if you put {-# LANGUAGE GeneralizedNewtypeDeriving #-} in a file, but never do newtype deriving, it would warn you?

I have no idea how hard that'd be to implement, but that sounds kind of cool. Useful for both refactoring and when you've inherited old code.

Cheers, C

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Peter Verswyvelen

10:27 a.m.

New subject: Request: warn about language extensions that are not used

Thanks Conal. For people interested, here's the ticket. http://hackage.haskell.org/trac/ghc/ticket/3085 Martijn Van Steenbergen indirectly revealed a feature request to the feature request feature of the feature database :-) Okay, I'll stop the nonsense: it would be nice if the community could rate the popularity of a feature request, which Martijn now just did by adding a comment. On Thu, Mar 12, 2009 at 3:12 PM, Conal Elliott wrote:

...

Thanks Peter. I'd love to have this feature also. I go back every so often and try removing each of the extensions listed in my LANGUAGE pragma. Didn't occur to me that the compiler could be doing it for me. Regards, - Conal

2009/3/11 Peter Verswyvelen

...
Okay, I submitted it as a GHC feature request. Thanks for the feedback. On Wed, Mar 11, 2009 at 5:16 PM, Creighton Hogg wrote:

...
2009/3/11 Peter Verswyvelen :

...
When I put {-# OPTIONS_GHC -Wall -Werror #-} in my source file, I don't get compiler (GHC) warnings about redundant language extensions that I enabled. It would be nice if the compiler gave warnings about this, since after refactoring, some language extensions might not be needed anymore, and hence should be removed since fewer language extensions mean more stable and portable code no? What do you think?

So you mean something like if you put {-# LANGUAGE GeneralizedNewtypeDeriving #-} in a file, but never do newtype deriving, it would warn you?

I have no idea how hard that'd be to implement, but that sounds kind of cool. Useful for both refactoring and when you've inherited old code.

Cheers, C

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Sittampalam, Ganesh

10:29 a.m.

New subject: Request: warn about language extensions that are not used

As I understand it the current scheme is that you vote for a bug by adding yourself to the CC list. ________________________________ From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Peter Verswyvelen Sent: 12 March 2009 14:27 To: Conal Elliott Cc: haskell mailing list Subject: Re: [Haskell-cafe] Request: warn about language extensions that are not used Thanks Conal. For people interested, here's the ticket. http://hackage.haskell.org/trac/ghc/ticket/3085 http://hackage.haskell.org/trac/ghc/ticket/3085 Martijn Van Steenbergen indirectly revealed a feature request to the feature request feature of the feature database :-) Okay, I'll stop the nonsense: it would be nice if the community could rate the popularity of a feature request, which Martijn now just did by adding a comment. On Thu, Mar 12, 2009 at 3:12 PM, Conal Elliott wrote: Thanks Peter. I'd love to have this feature also. I go back every so often and try removing each of the extensions listed in my LANGUAGE pragma. Didn't occur to me that the compiler could be doing it for me. Regards, - Conal 2009/3/11 Peter Verswyvelen Okay, I submitted it as a GHC feature request. Thanks for the feedback. On Wed, Mar 11, 2009 at 5:16 PM, Creighton Hogg wrote: 2009/3/11 Peter Verswyvelen : > When I put > {-# OPTIONS_GHC -Wall -Werror #-} > in my source file, I don't get compiler (GHC) warnings about redundant > language extensions that I enabled. > It would be nice if the compiler gave warnings about this, since after > refactoring, some language extensions might not be needed anymore, and hence > should be removed since fewer language extensions mean more stable and > portable code no? > What do you think? So you mean something like if you put {-# LANGUAGE GeneralizedNewtypeDeriving #-} in a file, but never do newtype deriving, it would warn you? I have no idea how hard that'd be to implement, but that sounds kind of cool. Useful for both refactoring and when you've inherited old code. Cheers, C _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe =============================================================================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html ===============================================================================

Martijn van Steenbergen

11 Mar 11 Mar

12:18 p.m.

New subject: Request: warn about language extensions that are not used

I'd love that. I've been wanting this for a while, at least subconsciously. Thanks for making it explicit. :-) Peter Verswyvelen wrote:

...

When I put

{-# OPTIONS_GHC -Wall -Werror #-}

in my source file, I don't get compiler (GHC) warnings about redundant language extensions that I enabled.

It would be nice if the compiler gave warnings about this, since after refactoring, some language extensions might not be needed anymore, and hence should be removed since fewer language extensions mean more stable and portable code no?

What do you think?

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Conal Elliott
Creighton Hogg
Martijn van Steenbergen
Peter Verswyvelen
Sittampalam, Ganesh

Request: warn about language extensions that are not used

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