diff --git a/default.nix b/default.nix
index c33cef2..2eb40e9 100644
--- a/default.nix
+++ b/default.nix
@@ -144,14 +144,6 @@ lib.makeScope pkgs.newScope (self: {
           lockfiles = lib.getAttrFromPath [ "metadata" "files" ] poetryLock;
         in
         lib.listToAttrs (lib.mapAttrsToList (n: v: { name = moduleName n; value = v; }) lockfiles);
-      specialAttrs = [
-        "overrides"
-        "poetrylock"
-        "projectDir"
-        "pwd"
-        "preferWheels"
-      ];
-      passedAttrs = builtins.removeAttrs attrs specialAttrs;
       evalPep508 = mkEvalPep508 python;
 
       # Filter packages by their PEP508 markers & pyproject interpreter version
@@ -167,9 +159,8 @@ lib.makeScope pkgs.newScope (self: {
       #
       # We need to avoid mixing multiple versions of pythonPackages in the same
       # closure as python can only ever have one version of a dependency
-      baseOverlay = self: super:
+      baseOverlay = self: _super:
         let
-          getDep = depName: self.${depName};
           lockPkgs = builtins.listToAttrs (
             builtins.map
               (
@@ -218,13 +209,13 @@ lib.makeScope pkgs.newScope (self: {
                 }
             )
             # Null out any filtered packages, we don't want python.pkgs from nixpkgs
-            (self: super: builtins.listToAttrs (builtins.map (x: { name = moduleName x.name; value = null; }) incompatible))
+            (_self: _super: builtins.listToAttrs (builtins.map (x: { name = moduleName x.name; value = null; }) incompatible))
             # Create poetry2nix layer
             baseOverlay
           ] ++ # User provided overrides
           (if builtins.typeOf overrides == "list" then overrides else [ overrides ])
         );
-      packageOverrides = lib.foldr lib.composeExtensions (self: super: { }) overlays;
+      packageOverrides = lib.foldr lib.composeExtensions (_self: _super: { }) overlays;
       py = python.override { inherit packageOverrides; self = py; };
 
       inputAttrs = mkInputAttrs { inherit py pyProject; attrs = { }; includeBuildSystem = false; };
diff --git a/mk-poetry-dep.nix b/mk-poetry-dep.nix
index 5735e32..9f33c1d 100644
--- a/mk-poetry-dep.nix
+++ b/mk-poetry-dep.nix
@@ -136,11 +136,11 @@ pythonPackages.callPackage
         let
           compat = isCompatible (poetryLib.getPythonVersion python);
           deps = lib.filterAttrs
-            (n: v: v)
+            (_n: v: v)
             (
               lib.mapAttrs
                 (
-                  n: v:
+                  _n: v:
                     let
                       constraints = v.python or "";
                       pep508Markers = v.markers or "";
diff --git a/overrides.nix b/overrides.nix
index 7c7d0eb..9290cff 100644
--- a/overrides.nix
+++ b/overrides.nix
@@ -100,7 +100,7 @@ self: super:
   );
 
   black = super.black.overridePythonAttrs (
-    old: {
+    _old: {
       dontPreferSetupPy = true;
     }
   );
@@ -156,13 +156,13 @@ self: super:
   );
 
   cheroot = super.cheroot.overridePythonAttrs (
-    old: {
+    _old: {
       dontPreferSetupPy = true;
     }
   );
 
   cloudflare = super.cloudflare.overridePythonAttrs (
-    old: {
+    _old: {
       postPatch = ''
         rm -rf examples/*
       '';
@@ -228,7 +228,7 @@ self: super:
     '';
   });
 
-  daphne = super.daphne.overridePythonAttrs (old: {
+  daphne = super.daphne.overridePythonAttrs (_old: {
     postPatch = ''
       substituteInPlace setup.py --replace 'setup_requires=["pytest-runner"],' ""
     '';
@@ -427,7 +427,7 @@ self: super:
     DISABLE_LIBC_COMPATIBILITY = 1;
   });
 
-  grpcio-tools = super.grpcio-tools.overridePythonAttrs (old: {
+  grpcio-tools = super.grpcio-tools.overridePythonAttrs (_old: {
     outputs = [ "out" "dev" ];
   });
 
@@ -473,7 +473,7 @@ self: super:
   );
 
   hid = super.hid.overridePythonAttrs (
-    old: {
+    _old: {
       postPatch = ''
         found=
         for name in libhidapi-hidraw libhidapi-libusb libhidapi-iohidmanager libhidapi; do
@@ -566,14 +566,14 @@ self: super:
   );
 
   importlib-resources = super.importlib-resources.overridePythonAttrs (
-    old: {
+    _old: {
       # disable the removal of pyproject.toml, required because of setuptools_scm
       dontPreferSetupPy = true;
     }
   );
 
   intreehooks = super.intreehooks.overridePythonAttrs (
-    old: {
+    _old: {
       doCheck = false;
     }
   );
@@ -617,7 +617,7 @@ self: super:
   );
 
   jsonpickle = super.jsonpickle.overridePythonAttrs (
-    old: {
+    _old: {
       dontPreferSetupPy = true;
     }
   );
@@ -628,7 +628,7 @@ self: super:
   });
 
   jupyter = super.jupyter.overridePythonAttrs (
-    old: rec {
+    _old: rec {
       # jupyter is a meta-package. Everything relevant comes from the
       # dependencies. It does however have a jupyter.py file that conflicts
       # with jupyter-core so this meta solves this conflict.
@@ -678,7 +678,7 @@ self: super:
     propagatedBuildInputs = [ pkgs.libvirt ];
   });
 
-  licensecheck = super.licensecheck.overridePythonAttrs (old: {
+  licensecheck = super.licensecheck.overridePythonAttrs (_old: {
     dontPreferSetupPy = true;
   });
 
@@ -992,7 +992,7 @@ self: super:
     }
   );
 
-  paramiko = super.paramiko.overridePythonAttrs (old: {
+  paramiko = super.paramiko.overridePythonAttrs (_old: {
     doCheck = false; # requires networking
   });
 
@@ -1003,7 +1003,7 @@ self: super:
   );
 
   pdal = super.pdal.overridePythonAttrs (
-    old: {
+    _old: {
       PDAL_CONFIG = "${pkgs.pdal}/bin/pdal-config";
     }
   );
@@ -1035,7 +1035,7 @@ self: super:
     '';
   });
 
-  poetry-core = super.poetry-core.overridePythonAttrs (old: {
+  poetry-core = super.poetry-core.overridePythonAttrs (_old: {
     # "Vendor" dependencies (for build-system support)
     postPatch = ''
       echo "import sys" >> poetry/__init__.py
@@ -1182,7 +1182,7 @@ self: super:
   });
 
   pygame = super.pygame.overridePythonAttrs (
-    old: rec {
+    _old: rec {
       nativeBuildInputs = [
         pkgs.pkg-config
         pkgs.SDL
@@ -1284,7 +1284,7 @@ self: super:
   );
 
   pytoml = super.pytoml.overridePythonAttrs (
-    old: {
+    _old: {
       doCheck = false;
     }
   );
@@ -1394,7 +1394,7 @@ self: super:
     );
 
   pytest-datadir = super.pytest-datadir.overridePythonAttrs (
-    old: {
+    _old: {
       postInstall = ''
         rm -f $out/LICENSE
       '';
@@ -1411,7 +1411,7 @@ self: super:
   );
 
   pytest-django = super.pytest-django.overridePythonAttrs (
-    old: {
+    _old: {
       postPatch = ''
         substituteInPlace setup.py --replace "'pytest>=3.6'," ""
         substituteInPlace setup.py --replace "'pytest>=3.6'" ""
@@ -1428,7 +1428,7 @@ self: super:
   pytest-runner = super.pytest-runner or super.pytestrunner;
 
   pytest-pylint = super.pytest-pylint.overridePythonAttrs (
-    old: {
+    _old: {
       buildInputs = [ self.pytest-runner ];
     }
   );
@@ -1455,7 +1455,7 @@ self: super:
   });
 
   python-jose = super.python-jose.overridePythonAttrs (
-    old: {
+    _old: {
       buildInputs = [ self.pytest-runner ];
     }
   );
@@ -1485,7 +1485,7 @@ self: super:
   );
 
   pyusb = super.pyusb.overridePythonAttrs (
-    old: {
+    _old: {
       postPatch = ''
         libusb=${pkgs.libusb1.out}/lib/libusb-1.0${pkgs.stdenv.hostPlatform.extensions.sharedLibrary}
         test -f $libusb || { echo "ERROR: $libusb doesn't exist, please update/fix this build expression."; exit 1; }
@@ -1509,7 +1509,7 @@ self: super:
   );
 
   rockset = super.rockset.overridePythonAttrs (
-    old: rec {
+    _old: rec {
       postPatch = ''
         cp ./setup_rockset.py ./setup.py
       '';
@@ -1517,7 +1517,7 @@ self: super:
   );
 
   scaleapi = super.scaleapi.overridePythonAttrs (
-    old: {
+    _old: {
       postPatch = ''
         substituteInPlace setup.py --replace "install_requires = ['requests>=2.4.2', 'enum34']" "install_requires = ['requests>=2.4.2']" || true
       '';
@@ -1701,7 +1701,7 @@ self: super:
   );
 
   tensorflow = super.tensorflow.overridePythonAttrs (
-    old: {
+    _old: {
       postInstall = ''
         rm $out/bin/tensorboard
       '';
@@ -1709,7 +1709,7 @@ self: super:
   );
 
   tensorpack = super.tensorpack.overridePythonAttrs (
-    old: {
+    _old: {
       postPatch = ''
         substituteInPlace setup.cfg --replace "# will call find_packages()" ""
       '';
@@ -1811,7 +1811,7 @@ self: super:
   );
 
   vose-alias-method = super.vose-alias-method.overridePythonAttrs (
-    old: {
+    _old: {
       postInstall = ''
         rm -f $out/LICENSE
       '';
@@ -1883,7 +1883,7 @@ self: super:
         }
       ).wheel.override {
         inherit (self) buildPythonPackage bootstrapped-pip setuptools;
-      }).overrideAttrs (old: {
+      }).overrideAttrs (_old: {
         inherit (super.wheel) pname name version src;
       });
     in
@@ -2079,13 +2079,13 @@ self: super:
   );
 
   lazy-object-proxy = super.lazy-object-proxy.overridePythonAttrs (
-    old: {
+    _old: {
       # disable the removal of pyproject.toml, required because of setuptools_scm
       dontPreferSetupPy = true;
     }
   );
 
-  pendulum = super.pendulum.overridePythonAttrs (old: {
+  pendulum = super.pendulum.overridePythonAttrs (_old: {
     # Technically incorrect, but fixes the build error..
     preInstall = lib.optionalString stdenv.isLinux ''
       mv --no-clobber ./dist/*.whl $(echo ./dist/*.whl | sed s/'manylinux_[0-9]*_[0-9]*'/'manylinux1'/)
diff --git a/pep508.nix b/pep508.nix
index 5098c5c..ae83e49 100644
--- a/pep508.nix
+++ b/pep508.nix
@@ -157,9 +157,8 @@ let
         else if v == "False" then false
         else builtins.fromJSON v
       );
-      hasElem = needle: haystack: builtins.elem needle (builtins.filter (x: builtins.typeOf x == "string") (builtins.split " " haystack));
       op = {
-        "true" = x: y: true;
+        "true" = _x: _y: true;
         "<=" = x: y: op.">=" y x;
         "<" = x: y: lib.versionOlder (unmarshal x) (unmarshal y);
         "!=" = x: y: x != y;
diff --git a/plugins.nix b/plugins.nix
index b5e807c..95cb5cc 100644
--- a/plugins.nix
+++ b/plugins.nix
@@ -11,7 +11,7 @@ let
     , buildInputs ? [ ]
     }:
     let
-      env = self.python.withPackages (ps: plugins);
+      env = self.python.withPackages (_ps: plugins);
     in
     stdenv.mkDerivation {
       pname = drv.pname + "-with-plugins";
diff --git a/templates/app/flake.nix b/templates/app/flake.nix
index e87172d..fb1f806 100644
--- a/templates/app/flake.nix
+++ b/templates/app/flake.nix
@@ -10,7 +10,7 @@
       # Nixpkgs overlay providing the application
       overlay = nixpkgs.lib.composeManyExtensions [
         poetry2nix.overlay
-        (final: prev: {
+        (_final: prev: {
           # The application
           myapp = prev.poetry2nix.mkPoetryApplication {
             projectDir = ./.;
diff --git a/tests/canonical-module-names/default.nix b/tests/canonical-module-names/default.nix
index 3bc9807..e127110 100644
--- a/tests/canonical-module-names/default.nix
+++ b/tests/canonical-module-names/default.nix
@@ -10,9 +10,9 @@ poetry2nix.mkPoetryApplication {
     poetry2nix.defaultPoetryOverrides
     (import ./poetry-git-overlay.nix { inherit pkgs; })
     (
-      self: super: {
+      _self: super: {
         pyramid-deferred-sqla = super.pyramid-deferred-sqla.overridePythonAttrs (
-          old: {
+          _old: {
             postPatch = ''
               touch LICENSE
               substituteInPlace setup.py --replace 'setup_requires=["pytest-runner"],' ""
diff --git a/tests/canonical-module-names/poetry-git-overlay.nix b/tests/canonical-module-names/poetry-git-overlay.nix
index 902f161..e54e460 100644
--- a/tests/canonical-module-names/poetry-git-overlay.nix
+++ b/tests/canonical-module-names/poetry-git-overlay.nix
@@ -1,5 +1,5 @@
 { pkgs }:
-self: super: {
+_self: super: {
 
   pyramid-deferred-sqla = super.pyramid-deferred-sqla.overridePythonAttrs (
     _: {
diff --git a/tests/composable-defaults/default.nix b/tests/composable-defaults/default.nix
index 938bd89..ccedb22 100644
--- a/tests/composable-defaults/default.nix
+++ b/tests/composable-defaults/default.nix
@@ -1,9 +1,9 @@
 { lib, poetry2nix, python3 }:
 let
-  p2nix = poetry2nix.overrideScope' (self: super: {
+  p2nix = poetry2nix.overrideScope' (_self: super: {
 
-    defaultPoetryOverrides = (super.defaultPoetryOverrides.extend (pyself: pysuper: {
-      my-custom-pkg = super.my-custom-pkg.overridePythonAttrs (oldAttrs: { });
+    defaultPoetryOverrides = (super.defaultPoetryOverrides.extend (_pyself: _pysuper: {
+      my-custom-pkg = super.my-custom-pkg.overridePythonAttrs (_oldAttrs: { });
     }));
 
   });
@@ -12,7 +12,7 @@ in
 p2nix.mkPoetryApplication {
   python = python3;
   projectDir = ./.;
-  overrides = p2nix.overrides.withDefaults (self: super: {
+  overrides = p2nix.overrides.withDefaults (_self: super: {
     customjox = super.customjox;
   });
 }
diff --git a/tests/git-deps-pinned/poetry-git-overlay.nix b/tests/git-deps-pinned/poetry-git-overlay.nix
index 8c9c86b..75ead0f 100644
--- a/tests/git-deps-pinned/poetry-git-overlay.nix
+++ b/tests/git-deps-pinned/poetry-git-overlay.nix
@@ -1,5 +1,5 @@
 { pkgs }:
-self: super: {
+_self: super: {
 
   alembic = super.alembic.overridePythonAttrs (
     _: {
diff --git a/tests/override-default-support/default.nix b/tests/override-default-support/default.nix
index e6b0075..b0637ac 100644
--- a/tests/override-default-support/default.nix
+++ b/tests/override-default-support/default.nix
@@ -8,15 +8,15 @@ let
     overrides = [
       ((
         poetry2nix.defaultPoetryOverrides.overrideOverlay (
-          self: super: {
+          _self: super: {
             alembic = super.alembic.overrideAttrs (
-              old: {
+              _old: {
                 TESTING_FOOBAR = 42;
               }
             );
           }
         )
-      ).extend (pyself: pysuper: { })) # Test .extend for good measure
+      ).extend (_pyself: _pysuper: { })) # Test .extend for good measure
     ];
   };
 in
diff --git a/tests/override-support/default.nix b/tests/override-support/default.nix
index 7a356f3..ddb23a8 100644
--- a/tests/override-support/default.nix
+++ b/tests/override-support/default.nix
@@ -6,9 +6,9 @@ let
     poetrylock = ./poetry.lock;
     pyproject = ./pyproject.toml;
     overrides = poetry2nix.overrides.withDefaults (
-      self: super: {
+      _self: super: {
         alembic = super.alembic.overrideAttrs (
-          old: {
+          _old: {
             TESTING_FOOBAR = 42;
           }
         );
diff --git a/tests/prefer-wheel/default.nix b/tests/prefer-wheel/default.nix
index 383ae62..a49e247 100644
--- a/tests/prefer-wheel/default.nix
+++ b/tests/prefer-wheel/default.nix
@@ -7,7 +7,7 @@ let
     overrides = poetry2nix.overrides.withDefaults
       # This is also in overrides.nix but repeated for completeness
       (
-        self: super: {
+        _: super: {
           maturin = super.maturin.override {
             preferWheel = true;
           };