If you're filing an issue, here are the things which will help us a lot:

* State your GHC version.

* State your platform, OS and distribution if applicable.

* State your cabal version if applicable.

* Tell us how to replicate the problem. If we can't replicate it, we
  can't fix it.

* If the problem involves running Haddock on some source, please
  include the sample on which we can replicate, the smaller/cleaner
  the better. Include some images if you think it will help us.

* Include any other info you think might be relevant (sandbox? unusual
  setup?).