[Diffusion] [Committed] rCABAL2863a628f857: Add two local type signatures

[Austin Seipp]

No, this is a Phabricator bug due to some changes in how commit imports are
handled. I just upgraded earlier; I'm tracking it down now.

At minimum, I'll find a way to turn off the email spam.

On Fri, Jul 8, 2016 at 2:46 PM, Simon Peyton Jones via ghc-devs <
ghc-devs at haskell.org> wrote:

> I don’t believe I made this commit, or the ones around it.   Mysterious; I
> hope I’m not being impersonated!
>
>
>
> Simon
>
>
>
> *From:* noreply at phabricator.haskell.org [mailto:
> noreply at phabricator.haskell.org]
> *Sent:* 08 July 2016 20:43
> *To:* Simon Peyton Jones <simonpj at microsoft.com>
> *Subject:* [Diffusion] [Committed] rCABAL2863a628f857: Add two local type
> signatures
>
>
>
> simonpj committed rCABAL2863a628f857: Add two local type signatures
> (authored by simonpj).
>
>
>
> Add two local type signatures
>
> I'm adding these type signatures to satisfy the "do not generalise
> local let/where" rule that GHC is taking on.
>
> The signatures are clearly correct, but I was surprised at the
> polymorphism needed. For example
>
> parseOptVersion :: ReadP r Version
> parseOptVersion = parseQuoted ver <++ ver
>
> where ver :: ReadP r Version
>
>       ver = parse <++ return noVersion
>
>       noVersion = Version{ versionBranch=[], versionTags=[] }
>
> Note that 'ver' really is called at two different types! That
> in turn is because of the type of (<++)
>
> (<++) :: ReadP a a -> ReadP r a -> ReadP r a
>
> (+++) :: ReadP r a -> ReadP r a -> ReadP r a
>
> Note the "a a" in the first arg, which is very unusual.
> For example, compare the type of (+++).
>
> Changing it to match the type of (+++) makes ReadP fail to compile,
> though, so I assume it's right as it stands. But surely this deserves
> a comment?!
>
>
>
> *AFFECTED FILES*
>
> /Distribution/ParseUtils.hs
>
>
>
> *USERS*
>
> simonpj (Author)
>
>
>
> *COMMIT*
>
> https://phabricator.haskell.org/rCABAL2863a628f857
>
>
>
> *EMAIL PREFERENCES*
>
> https://phabricator.haskell.org/settings/panel/emailpreferences/
>
>
>
> *To: *simonpj
>
> _______________________________________________
> ghc-devs mailing list
> ghc-devs at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
>
>


-- 
Regards,

Austin Seipp, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com/
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