diff --git a/doc/languages-frameworks/haskell.section.md b/doc/languages-frameworks/haskell.section.md
index b727f2fb634..cba4d0561b0 100644
--- a/doc/languages-frameworks/haskell.section.md
+++ b/doc/languages-frameworks/haskell.section.md
@@ -103,8 +103,8 @@ command displays the complete list of available compilers:
 $ nix-env -f "<nixpkgs>" -qaP -A haskell.compiler
 haskell.compiler.ghc8101                 ghc-8.10.1
 haskell.compiler.integer-simple.ghc8101  ghc-8.10.1
-haskell.compiler.ghcHEAD                 ghc-8.11.20200403
-haskell.compiler.integer-simple.ghcHEAD  ghc-8.11.20200403
+haskell.compiler.ghcHEAD                 ghc-8.11.20200505
+haskell.compiler.integer-simple.ghcHEAD  ghc-8.11.20200505
 haskell.compiler.ghc822Binary            ghc-8.2.2-binary
 haskell.compiler.ghc844                  ghc-8.4.4
 haskell.compiler.ghc863Binary            ghc-8.6.3-binary
diff --git a/pkgs/development/compilers/ghc/head.nix b/pkgs/development/compilers/ghc/head.nix
index d7fe37d1103..7b7ada77ac6 100644
--- a/pkgs/development/compilers/ghc/head.nix
+++ b/pkgs/development/compilers/ghc/head.nix
@@ -35,7 +35,7 @@
 , # Whetherto build terminfo.
   enableTerminfo ? !stdenv.targetPlatform.isWindows
 
-, version ? "8.11.20200403"
+, version ? "8.11.20200505"
 , # What flavour to build. An empty string indicates no
   # specific flavour and falls back to ghc default values.
   ghcFlavour ? stdenv.lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)
@@ -103,8 +103,8 @@ stdenv.mkDerivation (rec {
 
   src = fetchgit {
     url = "https://gitlab.haskell.org/ghc/ghc.git/";
-    rev = "4291bddaea3148908c55f235ee8978e1d9aa6f20";
-    sha256 = "1gs3mxmsdpsgsp7vnawx8mys0qwg4x2zhfrbciy3wv8nv13ar1af";
+    rev = "40c71c2cf38b4e134d81b7184a4d5e02949ae70c";
+    sha256 = "04h9rcyzm9w3an1z00hjs062dp7dl19b8pkyxjsypr7a2i9dmvkb";
   };
 
   enableParallelBuilding = true;
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index ae985f8b75d..13c5b721301 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -77,8 +77,8 @@ in {
     ghcHEAD = callPackage ../development/compilers/ghc/head.nix {
       bootPkgs = packages.ghc883; # no binary yet
       inherit (buildPackages.python3Packages) sphinx;
-      buildLlvmPackages = buildPackages.llvmPackages_9;
-      llvmPackages = pkgs.llvmPackages_9;
+      buildLlvmPackages = buildPackages.llvmPackages_10;
+      llvmPackages = pkgs.llvmPackages_10;
       libffi = pkgs.libffi;
     };
     ghcjs = compiler.ghcjs86;