diff --git a/pkgs/applications/science/logic/prooftree/default.nix b/pkgs/applications/science/logic/prooftree/default.nix
index a88a84e3b0d1..1f6620a2872d 100644
--- a/pkgs/applications/science/logic/prooftree/default.nix
+++ b/pkgs/applications/science/logic/prooftree/default.nix
@@ -1,6 +1,6 @@
-{stdenv, fetchurl, pkgconfig, ocaml, findlib, camlp5, ncurses, lablgtk ? null}:
+{ stdenv, fetchurl, pkgconfig, ncurses, ocamlPackages }:
 
-stdenv.mkDerivation (rec {
+stdenv.mkDerivation rec {
   name = "prooftree-${version}";
   version = "0.13";
 
@@ -10,7 +10,8 @@ stdenv.mkDerivation (rec {
   };
 
   nativeBuildInputs = [ pkgconfig ];
-  buildInputs = [ ocaml findlib camlp5 ncurses lablgtk ];
+  buildInputs = [ ncurses ] ++ (with ocamlPackages; [
+    ocaml findlib camlp5 lablgtk ]);
 
   dontAddPrefix = true;
   configureFlags = [ "--prefix" "$(out)" ];
@@ -39,4 +40,4 @@ stdenv.mkDerivation (rec {
     maintainers = [ maintainers.jwiegley ];
     license = licenses.gpl3;
   };
-})
+}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 866adafff53f..5a5ae8c1ba10 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -21278,7 +21278,7 @@ with pkgs;
 
   libpoly = callPackage ../applications/science/logic/poly {};
 
-  prooftree = ocamlPackages.callPackage  ../applications/science/logic/prooftree { };
+  prooftree = callPackage  ../applications/science/logic/prooftree {};
 
   prover9 = callPackage ../applications/science/logic/prover9 { };