diff --git a/pkgs/development/compilers/ghc/8.4.2.nix b/pkgs/development/compilers/ghc/8.4.2.nix
deleted file mode 100644
index ac8d76c63ed..00000000000
--- a/pkgs/development/compilers/ghc/8.4.2.nix
+++ /dev/null
@@ -1,208 +0,0 @@
-{ stdenv, targetPackages
-, buildPlatform, hostPlatform, targetPlatform
-
-# build-tools
-, bootPkgs, alex, happy, hscolour
-, autoconf, automake, coreutils, fetchurl, fetchpatch, perl, python3, m4
-
-, libffi, libiconv ? null, ncurses
-
-, useLLVM ? !targetPlatform.isx86
-, # LLVM is conceptually a run-time-only depedendency, but for
-  # non-x86, we need LLVM to bootstrap later stages, so it becomes a
-  # build-time dependency too.
-  buildLlvmPackages, llvmPackages
-
-, # If enabled, GHC will be built with the GPL-free but slower integer-simple
-  # library instead of the faster but GPLed integer-gmp library.
-  enableIntegerSimple ? !(gmp.meta.available or false), gmp
-
-, # If enabled, use -fPIC when compiling static libs.
-  enableRelocatedStaticLibs ? targetPlatform != hostPlatform
-
-, # Whether to build dynamic libs for the standard library (on the target
-  # platform). Static libs are always built.
-  enableShared ? !targetPlatform.isWindows && !targetPlatform.useAndroidPrebuilt && !targetPlatform.useiOSPrebuilt
-
-, # Whetherto build terminfo.
-  enableTerminfo ? !targetPlatform.isWindows
-
-, # What flavour to build. An empty string indicates no
-  # specific flavour and falls back to ghc default values.
-  ghcFlavour ? stdenv.lib.optionalString (targetPlatform != hostPlatform) "perf-cross"
-}:
-
-let
-  inherit (bootPkgs) ghc;
-
-  # TODO(@Ericson2314) Make unconditional
-  targetPrefix = stdenv.lib.optionalString
-    (targetPlatform != hostPlatform)
-    "${targetPlatform.config}-";
-
-  buildMK = ''
-    BuildFlavour = ${ghcFlavour}
-    ifneq \"\$(BuildFlavour)\" \"\"
-    include mk/flavours/\$(BuildFlavour).mk
-    endif
-    DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
-  '' + stdenv.lib.optionalString enableIntegerSimple ''
-    INTEGER_LIBRARY = integer-simple
-  '' + stdenv.lib.optionalString (targetPlatform != hostPlatform) ''
-    Stage1Only = YES
-    HADDOCK_DOCS = NO
-    BUILD_SPHINX_HTML = NO
-    BUILD_SPHINX_PDF = NO
-  '' + stdenv.lib.optionalString enableRelocatedStaticLibs ''
-    GhcLibHcOpts += -fPIC
-    GhcRtsHcOpts += -fPIC
-  '' + stdenv.lib.optionalString targetPlatform.useAndroidPrebuilt ''
-    EXTRA_CC_OPTS += -std=gnu99
-  '';
-
-  # Splicer will pull out correct variations
-  libDeps = platform: stdenv.lib.optional enableTerminfo [ ncurses ]
-    ++ stdenv.lib.optional (!enableIntegerSimple) gmp
-    ++ stdenv.lib.optional (platform.libc != "glibc" && !targetPlatform.isWindows) libiconv;
-
-  toolsForTarget =
-    if hostPlatform == buildPlatform then
-      [ targetPackages.stdenv.cc ] ++ stdenv.lib.optional useLLVM llvmPackages.llvm
-    else assert targetPlatform == hostPlatform; # build != host == target
-      [ stdenv.cc ] ++ stdenv.lib.optional useLLVM buildLlvmPackages.llvm;
-
-  targetCC = builtins.head toolsForTarget;
-
-in
-stdenv.mkDerivation rec {
-  version = "8.4.2";
-  name = "${targetPrefix}ghc-${version}";
-
-  src = fetchurl {
-    url = "https://downloads.haskell.org/~ghc/${version}/ghc-${version}-src.tar.xz";
-    sha256 = "0yq4y0smn92sksnjjva28b8847krxizns6rm50j3pgq69br35k01";
-  };
-
-  enableParallelBuilding = true;
-
-  outputs = [ "out" "doc" ];
-
-  patches = [(fetchpatch {
-    url = "https://git.haskell.org/hsc2hs.git/patch/738f3666c878ee9e79c3d5e819ef8b3460288edf";
-    sha256 = "0plzsbfaq6vb1023lsarrjglwgr9chld4q3m99rcfzx0yx5mibp3";
-    extraPrefix = "utils/hsc2hs/";
-    stripLen = 1;
-  })]
-    ++ stdenv.lib.optional stdenv.isDarwin ./backport-dylib-command-size-limit.patch;
-
-  postPatch = "patchShebangs .";
-
-  # GHC is a bit confused on its cross terminology.
-  preConfigure = ''
-    for env in $(env | grep '^TARGET_' | sed -E 's|\+?=.*||'); do
-      export "''${env#TARGET_}=''${!env}"
-    done
-    # GHC is a bit confused on its cross terminology, as these would normally be
-    # the *host* tools.
-    export CC="${targetCC}/bin/${targetCC.targetPrefix}cc"
-    export CXX="${targetCC}/bin/${targetCC.targetPrefix}cxx"
-    # Use gold to work around https://sourceware.org/bugzilla/show_bug.cgi?id=16177
-    export LD="${targetCC.bintools}/bin/${targetCC.bintools.targetPrefix}ld${stdenv.lib.optionalString targetPlatform.isAarch32 ".gold"}"
-    export AS="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}as"
-    export AR="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}ar"
-    export NM="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}nm"
-    export RANLIB="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}ranlib"
-    export READELF="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}readelf"
-    export STRIP="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}strip"
-
-    echo -n "${buildMK}" > mk/build.mk
-    sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
-  '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''
-    export NIX_LDFLAGS+=" -rpath $out/lib/ghc-${version}"
-  '' + stdenv.lib.optionalString stdenv.isDarwin ''
-    export NIX_LDFLAGS+=" -no_dtrace_dof"
-  '';
-
-  # TODO(@Ericson2314): Always pass "--target" and always prefix.
-  configurePlatforms = [ "build" "host" ]
-    ++ stdenv.lib.optional (targetPlatform != hostPlatform) "target";
-  # `--with` flags for libraries needed for RTS linker
-  configureFlags = [
-    "--datadir=$doc/share/doc/ghc"
-    "--with-curses-includes=${ncurses.dev}/include" "--with-curses-libraries=${ncurses.out}/lib"
-  ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && ! enableIntegerSimple) [
-    "--with-gmp-includes=${gmp.dev}/include" "--with-gmp-libraries=${gmp.out}/lib"
-  ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && hostPlatform.libc != "glibc" && !targetPlatform.isWindows) [
-    "--with-iconv-includes=${libiconv}/include" "--with-iconv-libraries=${libiconv}/lib"
-  ] ++ stdenv.lib.optionals (targetPlatform != hostPlatform) [
-    "--enable-bootstrap-with-devel-snapshot"
-  ] ++ stdenv.lib.optionals (targetPlatform.isAarch32) [
-    "CFLAGS=-fuse-ld=gold"
-    "CONF_GCC_LINKER_OPTS_STAGE1=-fuse-ld=gold"
-    "CONF_GCC_LINKER_OPTS_STAGE2=-fuse-ld=gold"
-  ] ++ stdenv.lib.optionals (targetPlatform.isDarwin && targetPlatform.isAarch64) [
-    # fix for iOS: https://www.reddit.com/r/haskell/comments/4ttdz1/building_an_osxi386_to_iosarm64_cross_compiler/d5qvd67/
-    "--disable-large-address-space"
-  ];
-
-  # Make sure we never relax`$PATH` and hooks support for compatability.
-  strictDeps = true;
-
-  nativeBuildInputs = [
-    perl autoconf automake m4 python3
-    ghc alex happy hscolour
-  ];
-
-  # For building runtime libs
-  depsBuildTarget = toolsForTarget;
-
-  buildInputs = libDeps hostPlatform;
-
-  propagatedBuildInputs = [ targetPackages.stdenv.cc ]
-    ++ stdenv.lib.optional useLLVM llvmPackages.llvm;
-
-  depsTargetTarget = map stdenv.lib.getDev (libDeps targetPlatform);
-  depsTargetTargetPropagated = map (stdenv.lib.getOutput "out") (libDeps targetPlatform);
-
-  # required, because otherwise all symbols from HSffi.o are stripped, and
-  # that in turn causes GHCi to abort
-  stripDebugFlags = [ "-S" ] ++ stdenv.lib.optional (!targetPlatform.isDarwin) "--keep-file-symbols";
-
-  checkTarget = "test";
-
-  hardeningDisable = [ "format" ];
-
-  postInstall = ''
-    for bin in "$out"/lib/${name}/bin/*; do
-      isELF "$bin" || continue
-      paxmark m "$bin"
-    done
-
-    # Install the bash completion file.
-    install -D -m 444 utils/completion/ghc.bash $out/share/bash-completion/completions/${targetPrefix}ghc
-
-    # Patch scripts to include "readelf" and "cat" in $PATH.
-    for i in "$out/bin/"*; do
-      test ! -h $i || continue
-      egrep --quiet '^#!' <(head -n 1 $i) || continue
-      sed -i -e '2i export PATH="$PATH:${stdenv.lib.makeBinPath [ targetPackages.stdenv.cc.bintools coreutils ]}"' $i
-    done
-  '';
-
-  passthru = {
-    inherit bootPkgs targetPrefix;
-
-    inherit llvmPackages;
-
-    # Our Cabal compiler name
-    haskellCompilerName = "ghc-8.4.2";
-  };
-
-  meta = {
-    homepage = http://haskell.org/ghc;
-    description = "The Glasgow Haskell Compiler";
-    maintainers = with stdenv.lib.maintainers; [ marcweber andres peti ];
-    inherit (ghc.meta) license platforms;
-  };
-
-}
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index c5f0378049e..ec471538095 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -66,12 +66,6 @@ in rec {
       buildLlvmPackages = buildPackages.llvmPackages_39;
       llvmPackages = pkgs.llvmPackages_39;
     };
-    ghc842 = callPackage ../development/compilers/ghc/8.4.2.nix rec {
-      bootPkgs = packages.ghc821Binary;
-      inherit (bootPkgs) alex happy hscolour;
-      buildLlvmPackages = buildPackages.llvmPackages_5;
-      llvmPackages = pkgs.llvmPackages_5;
-    };
     ghc843 = callPackage ../development/compilers/ghc/8.4.3.nix rec {
       bootPkgs = packages.ghc821Binary;
       inherit (bootPkgs) alex happy hscolour;
@@ -100,7 +94,7 @@ in rec {
       stage0 = ../development/compilers/ghcjs-ng/8.2/stage0.nix;
     };
     ghcjs84 = callPackage ../development/compilers/ghcjs-ng rec {
-      bootPkgs = packages.ghc842;
+      bootPkgs = packages.ghc843;
       inherit (bootPkgs) alex happy;
       ghcjsSrcJson = ../development/compilers/ghcjs-ng/8.4/git.json;
       stage0 = ../development/compilers/ghcjs-ng/8.4/stage0.nix;
@@ -151,11 +145,6 @@ in rec {
       ghc = bh.compiler.ghc822;
       compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-8.2.x.nix { };
     };
-    ghc842 = callPackage ../development/haskell-modules {
-      buildHaskellPackages = bh.packages.ghc842;
-      ghc = bh.compiler.ghc842;
-      compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-8.4.x.nix { };
-    };
     ghc843 = callPackage ../development/haskell-modules {
       buildHaskellPackages = bh.packages.ghc843;
       ghc = bh.compiler.ghc843;