[Haskell-cafe] :i and :t give different types

Don Stewart dons at galois.com
Thu Feb 7 14:57:31 EST 2008


ryani.spam:
> It looks like there is a bug with unparsing of bang-constructors in ghci:
> 
> On 2/7/08, Don Stewart <dons at galois.com> wrote:
> >    data Stream a = forall s. Unlifted s =>
> >                              Stream !(s -> Step a s)  -- ^ a stepper function
> >                                     !s                -- ^ an initial state
> 
> >    Prelude Data.Stream> :info Stream
> >    data Stream a where
> >      Stream :: forall a s.
> >                (Data.Stream.Unlifted s) =>
> >                !s -> Step a s -> !s -> Stream a
> 
> This last line should start with !(s -> Step a s) instead of !s -> Step a s.
> 
> If that was fixed, everything looks correct.

Ah, yes, missing parens! Well spotted.

So a pretty printer wibble in GHC?

-- Don


More information about the Haskell-Cafe mailing list