This repository demonstrates the bug at haskell/cabal#1896
There are three tags of interest cabal-1.7.0, cabal-1.7.1 and no-lib.
The commit message for each along with the discussion on the above ticket
explain what they are and what they do.
The bug can be exercised by running test.sh. Note only cabal-1.7.1 will
exercise the bug.