diff --git a/pkgs/development/libraries/clipper/default.nix b/pkgs/development/libraries/clipper/default.nix
index 9eb34f6b6863..929bf90d9c48 100644
--- a/pkgs/development/libraries/clipper/default.nix
+++ b/pkgs/development/libraries/clipper/default.nix
@@ -10,8 +10,6 @@ stdenv.mkDerivation rec {
 
   sourceRoot = "cpp";
 
-  buildInputs = [ ];
-
   nativeBuildInputs = [ cmake ninja unzip ];
 
   meta = with lib; {
diff --git a/pkgs/development/libraries/getdns/default.nix b/pkgs/development/libraries/getdns/default.nix
index 509a9bbbba54..0c6fa4a1e633 100644
--- a/pkgs/development/libraries/getdns/default.nix
+++ b/pkgs/development/libraries/getdns/default.nix
@@ -16,13 +16,9 @@ in rec {
     outputs = [ "out" "dev" "lib" "man" ];
 
     src = fetchurl {
-      url = "https://getdnsapi.net/releases/${pname}-${
-          with builtins;
-          concatStringsSep "-" (splitVersion version)
-        }/${pname}-${version}.tar.gz";
-      sha256 =
-        # upstream publishes hashes in hex format
-        "f1404ca250f02e37a118aa00cf0ec2cbe11896e060c6d369c6761baea7d55a2c";
+      url = with lib; "https://getdnsapi.net/releases/${pname}-${concatStringsSep "-" (splitVersion version)}/${pname}-${version}.tar.gz";
+      # upstream publishes hashes in hex format
+      sha256 = "f1404ca250f02e37a118aa00cf0ec2cbe11896e060c6d369c6761baea7d55a2c";
     };
 
     nativeBuildInputs = [ cmake doxygen ];
diff --git a/pkgs/development/libraries/minizip/default.nix b/pkgs/development/libraries/minizip/default.nix
index 1fb737ed7a75..5619fe7039e6 100644
--- a/pkgs/development/libraries/minizip/default.nix
+++ b/pkgs/development/libraries/minizip/default.nix
@@ -2,8 +2,7 @@
 
 stdenv.mkDerivation {
   pname = "minizip";
-  version = zlib.version;
-  inherit (zlib) src;
+  inherit (zlib) src version;
 
   nativeBuildInputs = [ autoreconfHook ];
   buildInputs = [ zlib ];
diff --git a/pkgs/games/keeperrl/default.nix b/pkgs/games/keeperrl/default.nix
index 8fb6d563329b..07e0008f878c 100644
--- a/pkgs/games/keeperrl/default.nix
+++ b/pkgs/games/keeperrl/default.nix
@@ -13,18 +13,18 @@
 , libtheora
 , unfree_assets ? false }:
 
-stdenv.mkDerivation rec {
+let
   pname = "keeperrl";
   version = "alpha34";
 
   free-src = fetchFromGitHub {
     owner = "miki151";
-    repo = "keeperrl";
+    repo = pname;
     rev = version;
     sha256 = "sha256-0sww+ppctXvxMouclG3OdXpcNgrrOZJw9z8s2GhJ+IE=";
   };
 
-  assets = if unfree_assets then requireFile rec {
+  assets = requireFile rec {
     name = "keeperrl_data_${version}.tar.gz";
     message = ''
       This nix expression requires that the KeeperRL art assets are already
@@ -39,11 +39,18 @@ stdenv.mkDerivation rec {
       "nix-prefetch-url file://\$PWD/${name}".
     '';
     sha256 = "0115pxdzdyma2vicxgr0j21pp82gxdyrlj090s8ihp0b50f0nlll";
-  } else null;
+  };
+in
+
+stdenv.mkDerivation {
+  inherit pname version;
+
+  srcs = [ free-src ] ++ lib.optional unfree_assets assets;
 
   sourceRoot = free-src.name;
 
-  srcs = [ free-src ] ++ lib.optional unfree_assets assets;
+  inherit free-src;
+  assets = if unfree_assets then assets else null;
 
   postUnpack = lib.optionalString unfree_assets ''
     mv data $sourceRoot