Unknown option -XPatternSig used in warning
Hello,
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.7.20070915
When loading the following incorrect program in ghci:
foo (x :: a) = x
ghci rightly complains:
Illegal signature in pattern: a
Use -XPatternSigs to permit it
OK so I follow the advice and load:
{-# OPTIONS_GHC -XPatternSigs #-}
foo (x :: a) = x
Now ghci complains:
unknown flags in {-# OPTIONS #-} pragma: -XPatternSigs ???
The following works though:
{-# OPTIONS_GHC -fglasgow-exts #-}
foo (x :: a) = x
results in:
A pattern type signature cannot bind scoped type variables `a'
unless the pattern has a rigid type context
In the pattern: x :: a
In the definition of `foo': foo (x :: a) = x
Which I expect.
Should I file a bug report, or is there an easy fix?
regards,
Bas van Dijk
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RE: Unknown option -XPatternSig used in warning
I believe this is a known problem with OPTIONS_GHC, and will work on the
command line. I think Ian is working on it. Ian?
Simon
| -Original Message-
| From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
| Behalf Of Bas van Dijk
| Sent: 19 September 2007 13:20
| To: glasgow-haskell-users@haskell.org
| Subject: Unknown option -XPatternSig used in warning
|
| Hello,
|
| $ ghc --version
| The Glorious Glasgow Haskell Compilation System, version 6.7.20070915
|
|
| When loading the following incorrect program in ghci:
|
| foo (x :: a) = x
|
| ghci rightly complains:
|
| Illegal signature in pattern: a
| Use -XPatternSigs to permit it
|
| OK so I follow the advice and load:
|
| {-# OPTIONS_GHC -XPatternSigs #-}
|
| foo (x :: a) = x
|
| Now ghci complains:
|
| unknown flags in {-# OPTIONS #-} pragma: -XPatternSigs ???
|
| The following works though:
|
| {-# OPTIONS_GHC -fglasgow-exts #-}
|
| foo (x :: a) = x
|
| results in:
|
| A pattern type signature cannot bind scoped type variables `a'
| unless the pattern has a rigid type context
| In the pattern: x :: a
| In the definition of `foo': foo (x :: a) = x
|
| Which I expect.
|
| Should I file a bug report, or is there an easy fix?
|
| regards,
|
| Bas van Dijk
| ___
| Glasgow-haskell-users mailing list
| Glasgow-haskell-users@haskell.org
| http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
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Re: Unknown option -XPatternSig used in warning
On 9/19/07, Simon Peyton-Jones [EMAIL PROTECTED] wrote: I believe this is a known problem with OPTIONS_GHC, and will work on the command line. I think Ian is working on it. Ian? Via the command line I get the same problem: $ ghci -XPatternSigs PatternSig.hs GHCi, version 6.7.20070915: http://www.haskell.org/ghc/ :? for help ghc-6.7.20070915: unrecognised flags: -XPatternSigs Usage: For basic information, try the `--help' option. Bas ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Unknown option -XPatternSig used in warning
| Illegal signature in pattern: a | Use -XPatternSigs to permit it | I am very happy to see that it doesn't recommend -fglasgow-exts anymore! However, I still would prefer Use LANGUAGE pragma with extension ``PatternSigs'' to permit it since it points out even more things that many may not have known before... By the way, some of my LANGUAGE pragmas are getting quite long, and last time I tried I was not allowed to have a line break in there. Are there any plans to allow line breaks, or multiple LANGUAGE pragmas? Wolfram ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Unknown option -XPatternSig used in warning
Via the command line I get the same problem: $ ghci -XPatternSigs PatternSig.hs GHCi, version 6.7.20070915: http://www.haskell.org/ghc/ :? for help ghc-6.7.20070915: unrecognised flags: -XPatternSigs Usage: For basic information, try the `--help' option. $ /cygdrive/c/fptools/ghc/compiler/stage2/ghc-inplace --supported-languages | grep Pat PatternGuards PatternSignatures BangPatterns MonoPatBinds could it be that the error message is incorrect, pointing to an abbreviated form? Illegal signature in pattern: a Use -XPatternSigs to permit it claus ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Unknown option -XPatternSig used in warning
On 9/19/07, Simon Peyton-Jones [EMAIL PROTECTED] wrote: ...I'll push a fix. Thanks! It works now: $ ghci -XPatternSignatures PatternSig.hs GHCi, version 6.9.20070919: http://www.haskell.org/ghc/ :? for help Loading package base ... linking ... done. [1 of 1] Compiling Main ( PatternSig.hs, interpreted ) PatternSig.hs:2:10: Not in scope: type variable `a' Failed, modules loaded: none. Bas ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Unknown option -XPatternSig used in warning
On 9/19/07, Wolfgang Jeltsch [EMAIL PROTECTED] wrote:
You should use {-# LANGUAGE PatternSigs #-}
That should be: {-# LANGUAGE PatternSignatures #-}
It would indeed be better if GHC could print Use LANGUAGE pragma with
extension... like Wolfram mentioned.
Bas
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Re: Unknown option -XPatternSig used in warning
Hi Wolfram,
On Wed, Sep 19, 2007 at 01:45:00PM -, [EMAIL PROTECTED] wrote:
By the way, some of my LANGUAGE pragmas are getting quite long,
and last time I tried I was not allowed to have a line break in there.
What version of GHC are you using? This works in 6.6:
{-# LANGUAGE MultiParamTypeClasses,
OverlappingInstances #-}
module Q where
class Foo a b where
foo :: a - b
instance Foo Int Bool
instance Foo Int a
x :: Int - Bool
x = foo
Are there any plans to allow line breaks,
or multiple LANGUAGE pragmas?
This also works:
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverlappingInstances #-}
module Q where
class Foo a b where
foo :: a - b
instance Foo Int Bool
instance Foo Int a
x :: Int - Bool
x = foo
Thanks
Ian
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