problems building trhsx-0.2 with ghc-6.5.20050723

[Konovalov, Vadim]

I built and installed ghc-6.5.20050723 on Linux from sources successfully,
and it looks quite normally-working.

I've stepped into a problem building trhsx from a package
haskell-src-exts-0.2.tar.gz with a quite unexpected (for me) message:

Preprocessing executables for trhsx-0.2...
Building trhsx-0.2...
hsSourceDirs: ["."]
Chasing modules from: Hsx.hs

Hsx.hs:6:7:
    Could not find module `Data.List':
      it is a member of package base-1.0, which is hidden

Lines in error is quite innocent-looking:
import Data.List (intersperse, isPrefixOf)

GHC version 6.4 builds that module okay.

Is that error is due to beta version of ghc-6.5.20050723, or I am
misunderstanding some configuration issues?

TIA,
Vadim.