haddock failure

I can't build haddock on current master aka v1.1.0:

.../cql-io $ stack haddock -v --ghc-options=-Wwarn
[...]
019-03-27 08:47:24.701211: [info] Documentation created:
2019-03-27 08:47:24.701401: [info] .stack-work/dist/x86_64-linux/Cabal-2.0.1.0/doc/html/cql-io/index.html,
2019-03-27 08:47:24.701497: [warn] Cabal-simple_mPHDZzAJ_2.0.1.0_ghc-8.2.2: internal error when calculating
2019-03-27 08:47:24.701564: [info] .stack-work/dist/x86_64-linux/Cabal-2.0.1.0/doc/html/cql-io/cql-io.txt
2019-03-27 08:47:24.701623: [warn] transitive package dependencies.
2019-03-27 08:47:24.701668: [info] Preprocessing library for cql-io-1.1.0..
2019-03-27 08:47:24.701713: [warn] Debug info: []
2019-03-27 08:47:24.701771: [info] Running Haddock on library for cql-io-1.1.0..

--  While building package cql-io-1.1.0 using:
      /home/mf/.stack/setup-exe-cache/x86_64-linux/Cabal-simple_mPHDZzAJ_2.0.1.0_ghc-8.2.2 --builddir=.stack-work/dist/x86_64-linux/Cabal-2.0.1.0 haddock --html --hoogle --html-location=../$pkg-$version/ --haddock-option=--hyperlinked-source
    Process exited with code: ExitFailure 1