The problem seems more wide-spread, so should probably be fixed within import/cabal.scm.
E.g. warp: http://hackage.haskell.org/package/warp-3.2.27/warp.cabal http://hackage.haskell.org/package/streaming-commons-0.2.1.0/streaming-commons.cabal contain things along the following lines: benchmark builder-to-bytestring-io ... build-depends: base , bytestring >= 0.10.2 , gauge , deepseq , streaming-commons if flag(use-bytestring-builder) build-depends: bytestring < 0.10.2.0 , bytestring-builder This kind of out-dented conditional seems not very rare.
