No instance for (Fractional Int32)

Christopher Vollick 0 at
Fri Feb 8 18:07:11 CET 2013

On Fri, Feb 08, 2013 at 01:20:53PM +0100, Gabor Greif wrote:
> libraries/base/Foreign/C/Types.hs:162:72:
>     No instance for (Fractional Int32)
>       arising from the 'deriving' clause of a data type declaration
>     Possible fix:
>       use a standalone 'deriving instance' declaration,
>         so you can specify the instance context yourself
>     When deriving the instance for (Fractional CFloat)
> Has anybody seen this with HEAD?

Yeah, I have.

I was going to look into why, but then I forgot.

I worked around it by going into libraries/base and running ./configure
--target=whatever manually.
Then, when I built it worked for some reason.

Then, when building from the top again, it didn't rebuild base.

If you wanted to figure out why, you have my blessing.
I'm assuming something gets passed down that shouldn't, or something.

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