diff --git a/pkgs/development/haskell-modules/configuration-ghc-8.6.x.nix b/pkgs/development/haskell-modules/configuration-ghc-8.6.x.nix
index 2a0a7810f72a..8e87134f617c 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-8.6.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-8.6.x.nix
@@ -94,4 +94,6 @@ self: super: {
 
   # This became a core library in ghc 8.10., so we don‘t have an "exception" attribute anymore.
   exceptions = super.exceptions_0_10_4;
+
+  mmorph = super.mmorph_1_1_3;
 }
diff --git a/pkgs/development/haskell-modules/configuration-hackage2nix.yaml b/pkgs/development/haskell-modules/configuration-hackage2nix.yaml
index 96ca00e0a45a..3dcadefccc3c 100644
--- a/pkgs/development/haskell-modules/configuration-hackage2nix.yaml
+++ b/pkgs/development/haskell-modules/configuration-hackage2nix.yaml
@@ -2712,6 +2712,7 @@ extra-packages:
   - dependent-sum == 0.4                # required by Hasura 1.3.1, 2020-08-20
   - network == 2.6.3.1                  # required by pkgs/games/hedgewars/default.nix, 2020-11-15
   - apply-refact == 0.8.2.1             # Needed for hls 0.8.0
+  - mmorph == 1.1.3                     # Newest working version of mmorph on ghc 8.6.5. needed for hls
 
 package-maintainers:
   peti:
diff --git a/pkgs/development/haskell-modules/hackage-packages.nix b/pkgs/development/haskell-modules/hackage-packages.nix
index 3a675707c43d..b1a2837ec6d0 100644
--- a/pkgs/development/haskell-modules/hackage-packages.nix
+++ b/pkgs/development/haskell-modules/hackage-packages.nix
@@ -174058,6 +174058,20 @@ self: {
        license = lib.licenses.bsd3;
      }) {};
 
+  "mmorph_1_1_3" = callPackage
+    ({ mkDerivation, base, mtl, transformers, transformers-compat }:
+     mkDerivation {
+       pname = "mmorph";
+       version = "1.1.3";
+       sha256 = "0rfsy9n9mlinpmqi2s17fhc67fzma2ig5fbmh6m5m830canzf8vr";
+       libraryHaskellDepends = [
+         base mtl transformers transformers-compat
+       ];
+       description = "Monad morphisms";
+       license = lib.licenses.bsd3;
+       hydraPlatforms = lib.platforms.none;
+     }) {};
+
   "mmorph" = callPackage
     ({ mkDerivation, base, mtl, transformers, transformers-compat }:
      mkDerivation {