On Wed, Dec 24, 2014 at 10:49:15PM +1300, Chris Wong wrote:

You're experiencing a phenomenon commonly known as "dependency hell". The usual and most straightforward solution is to nuke ~/.cabal and ~/.ghc and reinstall.

YMMV but I've always had good results just deleting .ghc and leaving .cabal alone. (I have GHC and Cabal install globally by my Debian distribution package manager, if that makes any difference.) Tom

Thanks, Chris and everybody else. The thing is, and I just finished to re-check, that this error happens even after I did `rm ~/.ghc; rm ~/.cabal`, so this happens upon fresh install. Thanks for links, I will spend some time later to learn to get more understanding on what exactly goes wrong. On Wed, Dec 24, 2014 at 11:49 AM, Chris Wong wrote:

Hi Konstantine,

You're experiencing a phenomenon commonly known as "dependency hell". The usual and most straightforward solution is to nuke ~/.cabal and ~/.ghc and reinstall.

In the future, you should aim to install as many packages as possible in one go, so that Cabal can ensure they work together up front. Also, if you have multiple projects going, consider using Cabal sandboxes to keep them separate.

These links might help: * https://cdsmith.wordpress.com/2011/01/17/the-butterfly-effect-in-cabal/ * http://www.vex.net/~trebla/haskell/sicp.xhtml * http://coldwa.st/e/blog/2013-08-20-Cabal-sandbox.html

Chris

On Wed, Dec 24, 2014 at 8:06 PM, Konstantine Rybnikov wrote:

...

Hi! I just got raspberry pi and installed debian wheezy on it. It has ghc 7.4.1 with cabal 1.14.0.

I tried to do cabal install cabal-install and got this:

``` In-place registering Cabal-1.20.0.3... Installing library in /home/pi/.cabal/lib/arm-linux-ghc-7.4.1/Cabal-1.20.0.3 Registering Cabal-1.20.0.3... Downloading cabal-install-1.20.0.4... Configuring cabal-install-1.20.0.4... cabal: At least the following dependencies are missing: random >=1 && <1.1 && ==1.1 cabal: Error: some packages failed to install: cabal-install-1.20.0.4 failed during the configure step. The exception was: ```

If I do `cabal list --installed | less` and search for random I see:

``` * random Synopsis: random number library Default available version: 1.1 Installed versions: 1.0.1.1, 1.1 License: BSD3 ```

Can anyone please help how do I resolve this and similar problems?

Thanks!

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