diff --git a/pkgs/development/libraries/haskell/unordered-containers/0.2.5.0.nix b/pkgs/development/libraries/haskell/unordered-containers/0.2.5.0.nix
index 508199bb0a7..70f00b68d42 100644
--- a/pkgs/development/libraries/haskell/unordered-containers/0.2.5.0.nix
+++ b/pkgs/development/libraries/haskell/unordered-containers/0.2.5.0.nix
@@ -1,3 +1,5 @@
+# This file was auto-generated by cabal2nix. Please do NOT edit manually!
+
 { cabal, ChasingBottoms, deepseq, hashable, HUnit, QuickCheck
 , testFramework, testFrameworkHunit, testFrameworkQuickcheck2
 }:
diff --git a/pkgs/development/tools/parsing/happy/1.19.4.nix b/pkgs/development/tools/parsing/happy/1.19.4.nix
index c1dee08c5cc..e7cd358fb82 100644
--- a/pkgs/development/tools/parsing/happy/1.19.4.nix
+++ b/pkgs/development/tools/parsing/happy/1.19.4.nix
@@ -1,3 +1,5 @@
+# This file was auto-generated by cabal2nix. Please do NOT edit manually!
+
 { cabal, mtl, perl }:
 
 cabal.mkDerivation (self: {