Andrés Sicard-Ramírez
I found a different problem installing vector on Ubuntu precise (12.04LTS):
$ cabal install vector ... Installed primitive-0.6.1.0 Configuring vector-0.11.0.0... ... Data/Vector/Generic/Mutable/Base.hs:18:1: error: Bad interface file: /home/asr/.cabal/lib/x86_64-linux-ghc-8.0.0.20160111/primitive-0.6.1.0-6R7Tzfc83qM6k1j6TLqRai/Control/Monad/Primitive.hi Something is amiss; requested module primitive-0.6.1.0@primitive-0.6.1.0-de94d43ed2b084399e39dfe5a3f60217:Control.Monad.Primitive differs from name found in the interface file primi_6R7Tzfc83qM6k1j6TLqRai:Control.Monad.Primitive Failed to install vector-0.11.0.0
I have found the same "Bad interface file" problem installing other packages.
Ahh yes; I suspected I was missing something in the release announcement. Due to unfortunate Cabal/GHC interactions, GHC 8.0 will require Cabal 0.23. These interface file issues should be cleared up by wiping your 8.0.1 package database, installing Cabal and cabal-install 0.23 (only available from the upstream repository at the moment), and trying to install vector again. The reason for this is a change in how packages are identified in GHC 8.0. While previous versions of Cabal identified packages to GHC with a package key (with GHC's -this-package-key argument), GHC 8.0 and later uses another, more specific identifier, the installed package ID. For compatibility reasons -this-package-key is currently accepted by GHC as a synonym for -package-name. This is a bit unfortunate, however, as the two flags aren't really synonymous. This is the reason why cabal-install fails. I'm discussing this with Edward Yang and hopefully we'll be able to have a louder, more obvious failure in place for rc2. I'll be sure to mention this in future release announcements. Cheers, - Ben