diff --git a/flake.nix b/flake.nix
index 9f726b0..99fbfc3 100644
--- a/flake.nix
+++ b/flake.nix
@@ -34,7 +34,8 @@
           inherit system;
           overlays = [
             gen-luarc.overlays.default
-            (import ./nix/overlay.nix {inherit self;})
+            self.overlays.default
+            (import ./nix/fixture-overlay.nix {inherit self;})
           ];
         };
         luarc = pkgs.mk-luarc {
@@ -110,5 +111,8 @@
             ;
         };
       };
+      flake = {
+        overlays.default = import ./nix/overlay.nix {inherit self;};
+      };
     };
 }
diff --git a/nix/fixture-overlay.nix b/nix/fixture-overlay.nix
new file mode 100644
index 0000000..465b331
--- /dev/null
+++ b/nix/fixture-overlay.nix
@@ -0,0 +1,108 @@
+{self}: final: prev: let
+  luaPackage-override = luaself: luaprev: {
+    tree-sitter-rust = luaself.callPackage ({
+      buildLuarocksPackage,
+      fetchFromGitHub,
+      luaOlder,
+      luarocks-build-treesitter-parser,
+    }:
+      buildLuarocksPackage {
+        pname = "tree-sitter-rust";
+        version = "scm-1";
+        knownRockspec = "${self}/fixtures/tree-sitter-rust-scm-1.rockspec";
+        src = fetchFromGitHub {
+          owner = "tree-sitter";
+          repo = "tree-sitter-rust";
+          rev = "3a56481f8d13b6874a28752502a58520b9139dc7";
+          hash = "sha256-6ROXeKuPehtIOtaI1OJuTtyPfQmZyLzCxv3ZS04yAIk=";
+        };
+        propagatedBuildInputs = [
+          luarocks-build-treesitter-parser
+        ];
+        disabled = luaOlder "5.1";
+      }) {};
+
+    tree-sitter-ocamllex = luaself.callPackage ({
+      buildLuarocksPackage,
+      fetchFromGitHub,
+      luaOlder,
+      luarocks-build-treesitter-parser,
+      tree-sitter,
+      nodejs_21,
+    }:
+      buildLuarocksPackage {
+        pname = "tree-sitter-ocamllex";
+        version = "scm-1";
+        knownRockspec = "${self}/fixtures/tree-sitter-ocamllex-scm-1.rockspec";
+        src = fetchFromGitHub {
+          owner = "atom-ocaml";
+          repo = "tree-sitter-ocamllex";
+          rev = "4b9898ccbf198602bb0dec9cd67cc1d2c0a4fad2";
+          hash = "sha256-YhmEE7I7UF83qMuldHqc/fD/no/7YuZd6CaAIaZ1now=";
+        };
+        buildInputs = [
+          tree-sitter
+          nodejs_21
+        ];
+        propagatedBuildInputs = [
+          luarocks-build-treesitter-parser
+        ];
+        disabled = luaOlder "5.1";
+      }) {};
+
+    tree-sitter-toml = luaself.callPackage ({
+      buildLuarocksPackage,
+      fetchFromGitHub,
+      luaOlder,
+      luarocks-build-treesitter-parser,
+      tree-sitter,
+      nodejs_21,
+    }:
+      buildLuarocksPackage {
+        pname = "tree-sitter-toml";
+        version = "scm-1";
+        knownRockspec = "${self}/fixtures/tree-sitter-toml-scm-1.rockspec";
+        src = fetchFromGitHub {
+          owner = "ikatyang";
+          repo = "tree-sitter-toml";
+          rev = "8bd2056818b21860e3d756b5a58c4f6e05fb744e";
+          hash = "sha256-z9MWNOBxLHBd/pVs5/QiSSGtaW+DUd7y3wZXcl3hWnk=";
+        };
+        buildInputs = [
+          tree-sitter
+          nodejs_21
+        ];
+        propagatedBuildInputs = [
+          luarocks-build-treesitter-parser
+        ];
+        disabled = luaOlder "5.1";
+      }) {};
+
+    tree-sitter-xml = luaself.callPackage ({
+      buildLuarocksPackage,
+      fetchFromGitHub,
+      luaOlder,
+      luarocks-build-treesitter-parser,
+    }:
+      buildLuarocksPackage {
+        pname = "tree-sitter-xml";
+        version = "scm-1";
+        knownRockspec = "${self}/fixtures/tree-sitter-xml-scm-1.rockspec";
+        src = fetchFromGitHub {
+          owner = "ObserverOfTime";
+          repo = "tree-sitter-xml";
+          rev = "c23bd31d0aa72bfc01238b2546d5e823d8006709";
+          hash = "sha256-oPjO7y2xSVxvP0bpCFo/oGP4hPs3kWJ728d/R5PUdK4=";
+        };
+        propagatedBuildInputs = [
+          luarocks-build-treesitter-parser
+        ];
+        disabled = luaOlder "5.1";
+      }) {};
+  };
+in {
+  lua5_1 = prev.lua5_1.override {
+    packageOverrides = luaPackage-override;
+  };
+  lua51Packages = final.lua5_1.pkgs;
+}
diff --git a/nix/overlay.nix b/nix/overlay.nix
index dc078e6..2083750 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -11,106 +11,6 @@
         src = self;
         disabled = luaOlder "5.1";
       }) {};
-
-    tree-sitter-rust = luaself.callPackage ({
-      buildLuarocksPackage,
-      fetchFromGitHub,
-      luaOlder,
-      luarocks-build-treesitter-parser,
-    }:
-      buildLuarocksPackage {
-        pname = "tree-sitter-rust";
-        version = "scm-1";
-        knownRockspec = "${self}/fixtures/tree-sitter-rust-scm-1.rockspec";
-        src = fetchFromGitHub {
-          owner = "tree-sitter";
-          repo = "tree-sitter-rust";
-          rev = "3a56481f8d13b6874a28752502a58520b9139dc7";
-          hash = "sha256-6ROXeKuPehtIOtaI1OJuTtyPfQmZyLzCxv3ZS04yAIk=";
-        };
-        propagatedBuildInputs = [
-          luarocks-build-treesitter-parser
-        ];
-        disabled = luaOlder "5.1";
-      }) {};
-
-    tree-sitter-ocamllex = luaself.callPackage ({
-      buildLuarocksPackage,
-      fetchFromGitHub,
-      luaOlder,
-      luarocks-build-treesitter-parser,
-      tree-sitter,
-      nodejs_21,
-    }:
-      buildLuarocksPackage {
-        pname = "tree-sitter-ocamllex";
-        version = "scm-1";
-        knownRockspec = "${self}/fixtures/tree-sitter-ocamllex-scm-1.rockspec";
-        src = fetchFromGitHub {
-          owner = "atom-ocaml";
-          repo = "tree-sitter-ocamllex";
-          rev = "4b9898ccbf198602bb0dec9cd67cc1d2c0a4fad2";
-          hash = "sha256-YhmEE7I7UF83qMuldHqc/fD/no/7YuZd6CaAIaZ1now=";
-        };
-        buildInputs = [
-          tree-sitter
-          nodejs_21
-        ];
-        propagatedBuildInputs = [
-          luarocks-build-treesitter-parser
-        ];
-        disabled = luaOlder "5.1";
-      }) {};
-
-    tree-sitter-toml = luaself.callPackage ({
-      buildLuarocksPackage,
-      fetchFromGitHub,
-      luaOlder,
-      luarocks-build-treesitter-parser,
-      tree-sitter,
-      nodejs_21,
-    }:
-      buildLuarocksPackage {
-        pname = "tree-sitter-toml";
-        version = "scm-1";
-        knownRockspec = "${self}/fixtures/tree-sitter-toml-scm-1.rockspec";
-        src = fetchFromGitHub {
-          owner = "ikatyang";
-          repo = "tree-sitter-toml";
-          rev = "8bd2056818b21860e3d756b5a58c4f6e05fb744e";
-          hash = "sha256-z9MWNOBxLHBd/pVs5/QiSSGtaW+DUd7y3wZXcl3hWnk=";
-        };
-        buildInputs = [
-          tree-sitter
-          nodejs_21
-        ];
-        propagatedBuildInputs = [
-          luarocks-build-treesitter-parser
-        ];
-        disabled = luaOlder "5.1";
-      }) {};
-
-    tree-sitter-xml = luaself.callPackage ({
-      buildLuarocksPackage,
-      fetchFromGitHub,
-      luaOlder,
-      luarocks-build-treesitter-parser,
-    }:
-      buildLuarocksPackage {
-        pname = "tree-sitter-xml";
-        version = "scm-1";
-        knownRockspec = "${self}/fixtures/tree-sitter-xml-scm-1.rockspec";
-        src = fetchFromGitHub {
-          owner = "ObserverOfTime";
-          repo = "tree-sitter-xml";
-          rev = "c23bd31d0aa72bfc01238b2546d5e823d8006709";
-          hash = "sha256-oPjO7y2xSVxvP0bpCFo/oGP4hPs3kWJ728d/R5PUdK4=";
-        };
-        propagatedBuildInputs = [
-          luarocks-build-treesitter-parser
-        ];
-        disabled = luaOlder "5.1";
-      }) {};
   };
 in {
   lua5_1 = prev.lua5_1.override {