On Sat, Jan 31, 2015 at 11:09 AM, Herbert Valerio Riedel <hvriedel@gmail.com> wrote:

On 2015-01-31 at 14:34:35 +0100, George Colpitts wrote:
> Maybe this is something I shouldn't be doing, but I thought it was worth
> mentioning in case I have found a compiler bug.
> Should I file a bug for this?
>
> cabal install *--allow-newer=base* accelerate
> ...
> [10 of 10] Compiling Data.Label.Base ( src/Data/Label/Base.hs,
> dist/build/Data/Label/Base.o )
> ghc: internal error: PAP object entered!
> (GHC version 7.10.0.20150123 for x86_64_apple_darwin)
> Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug

I suspect this has to do with `--allow-newer=base` allowing
template-haskell-2.9.0.0 to be re-installed (which then becomes a
build-dependency of `fclabels`). GHC 7.10, however, comes with
template-haskell-2.10.0.0

Ah yes, you're exactly right. I didn't encounter this when I tried to reproduce the issue because I have a bunch of lines like "constraint: template-haskell installed" in my .cabal/config file.

Regards,
Reid Barton