No instance for (Semigroup HttpData) with ghc 8.4.4

[adrianmay]

This Dockerfile reproduces the problem (after several cups of tea):

FROM gregweber/ghc-haskell-dev USER root RUN apt-get update RUN apt-get install wget USER ghc RUN wget https://downloads.haskell.org/~ghc/8.4.4/ghc-8.4.4-src.tar.xz RUN tar xf ghc-8.4.4-src.tar.xz RUN cd ghc-8.4.4; ./configure; make RUN wget https://www.haskell.org/cabal/release/cabal-2.4.0.0/Cabal-2.4.0.0.tar.gz RUN tar xf Cabal-2.4.0.0.tar.gz RUN cd Cabal-2.4.0.0; ghc -threaded --make Setup; RUN cd Cabal-2.4.0.0; ./Setup configure; ./Setup build; USER root RUN cd Cabal-2.4.0.0; ./Setup install RUN apt-get install libz-dev USER ghc RUN cabal install lens RUN cabal install cpphs RUN cabal install diagrams RUN cabal install MFlow

[agocorona]

Thanks.

Please use ghc-8.2 or less until this is fixed.