diff --git a/pkgs/development/compilers/ghc/8.6.5.nix b/pkgs/development/compilers/ghc/8.6.5.nix
index 3d660dd95217..7adacff597ca 100644
--- a/pkgs/development/compilers/ghc/8.6.5.nix
+++ b/pkgs/development/compilers/ghc/8.6.5.nix
@@ -110,10 +110,10 @@ stdenv.mkDerivation (rec {
   outputs = [ "out" "doc" ];
 
   patches = [
-    (fetchpatch rec { # https://phabricator.haskell.org/D5123
-     url = "http://tarballs.nixos.org/sha256/${sha256}";
+    (fetchpatch { # https://phabricator.haskell.org/D5123
+     url = "https://gitlab.haskell.org/ghc/ghc/-/commit/13ff0b7ced097286e0d7b054f050871effe07f86.diff";
      name = "D5123.diff";
-     sha256 = "0nhqwdamf2y4gbwqxcgjxs0kqx23w9gv5kj0zv6450dq19rji82n";
+     sha256 = "140lmnqxra7xkwy370c5pyf8dgdwgmbpcrs1dapnwr2dh8bavn8c";
     })
     (fetchpatch { # https://github.com/haskell/haddock/issues/900
      url = "https://patch-diff.githubusercontent.com/raw/haskell/haddock/pull/983.diff";