diff --git a/pkgs/development/tools/documentation/haddock/2.7.2.nix b/pkgs/development/tools/documentation/haddock/2.7.2.nix
index fd31a96b2913..8ceff01aca9d 100644
--- a/pkgs/development/tools/documentation/haddock/2.7.2.nix
+++ b/pkgs/development/tools/documentation/haddock/2.7.2.nix
@@ -5,7 +5,7 @@ cabal.mkDerivation (self : {
   version = "2.7.2"; # Haskell Platform 2010.1.0.0 and 2010.2.0.0
   name = self.fname;
   sha256 = "4eaaaf62785f0ba3d37ba356cfac4679faef91c0902d8cdbf42837cbe5daab82";
-  extraBuildInputs = [alex happy makeWrapper];
+  buildTools = [alex happy makeWrapper];
   propagatedBuildInputs = [ghcPaths];
   doCheck = false;
 
diff --git a/pkgs/development/tools/documentation/haddock/2.9.2.nix b/pkgs/development/tools/documentation/haddock/2.9.2.nix
index fcae14d789e9..05330b700ccb 100644
--- a/pkgs/development/tools/documentation/haddock/2.9.2.nix
+++ b/pkgs/development/tools/documentation/haddock/2.9.2.nix
@@ -5,7 +5,7 @@ cabal.mkDerivation (self : {
   version = "2.9.2"; # Haskell Platform 2011.2.0.0
   name = self.fname;
   sha256 = "189vvp173pqc69zgzqqx6vyhvsc13p1s86ql60rs1j5qlhh8ajg8";
-  extraBuildInputs = [alex happy makeWrapper];
+  buildTools = [alex happy makeWrapper];
   propagatedBuildInputs = [ghcPaths xhtml];
   doCheck = false;