Re: vector: ‘ANN type’ without GHCi

[Edward Kmett]

Unfortunately, that pragma pretty much makes the difference between vector
being fast, getting benefits out of stream fusion for all those
intermediate stream types and not.

It might be a much nicer story if stage-1 builds simply ignored ANN pragmas
entirely.

As it is I get complaints from distribution maintainers with wide
distributions about any use of module or function annotations for HLint,
and this particular ForceSpecConstr annotation has come up as a source of
pain for Austin before, though I've forgotten the details as to why.

-Edward


On Sun, Mar 30, 2014 at 6:05 PM, Nikita Karetnikov <nikita at karetnikov.org>wrote:

> The latest Hackage version and HEAD fail to build on mips64el due to the
> ANN pragma in ‘Data/Vector/Fusion/Stream/Monadic.hs’:
>
> [ 5 of 21] Compiling Data.Vector.Fusion.Stream.Monadic (
> Data/Vector/Fusion/Stream/Monadic.hs,
> dist/build/Data/Vector/Fusion/Stream/Monadic.o )
> ghc: panic! (the 'impossible' happened)
>   (GHC version 7.6.3 for mipsel-unknown-linux):
>         Cant do annotations without GHCi
>     {Data/Vector/Fusion/Stream/Monadic.hs:104:19-33}
>     base:GHC.Exts.ForceSpecConstr{d r2i8}
>
> Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
>
> Here’s the relevant part of the code:
>
> data SPEC = SPEC | SPEC2
> #if __GLASGOW_HASKELL__ >= 700
> {-# ANN type SPEC ForceSpecConstr #-}
> #endif
>
> Is it possible to use CPP along with some configure flag to determine if
> GHCi is available, and if it is not, skip the said pragma?  I tested the
> Hackage version, and it builds fine if I comment out the mentioned
> lines.
>
> Does the lack of the pragma make a big difference?  (The relevant
> section of the GHC manual is very brief.)
>
> _______________________________________________
> Libraries mailing list
> Libraries at haskell.org
> http://www.haskell.org/mailman/listinfo/libraries
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/libraries/attachments/20140330/cfcdeb2e/attachment.html>