diff --git a/.github/workflows/vader.yml b/.github/workflows/vader.yml
index 4dd97a2..559ca1e 100644
--- a/.github/workflows/vader.yml
+++ b/.github/workflows/vader.yml
@@ -22,6 +22,7 @@ jobs:
         run: pip install --pre vim-vint
       - name: Lint vimscript files
         run: vint --warning --enable-neovim ./after ./autoload ./compiler ./ftdetect ./ftplugin ./indent ./syntax
+      - uses: lunarmodules/luacheck@v1
       - uses: ludeeus/action-shellcheck@master
 
   tests:
diff --git a/.luacheckrc b/.luacheckrc
new file mode 100644
index 0000000..d5ec9fa
--- /dev/null
+++ b/.luacheckrc
@@ -0,0 +1,20 @@
+-- vim: ft=lua tw=80
+
+-- Global objects defined by the C code
+read_globals = {
+    vim = {
+        filetype = {
+            fields = {
+                add = {},
+                match = {},
+            }
+        },
+        b = {
+            fields = {
+                epuppet_subtype = {
+                    read_only=false,
+                }
+            }
+        }
+    }
+}
diff --git a/ftdetect/puppet.lua b/ftdetect/puppet.lua
index 021abc8..11b51a5 100644
--- a/ftdetect/puppet.lua
+++ b/ftdetect/puppet.lua
@@ -5,8 +5,8 @@ vim.filetype.add({
     extension = {
         epp =
             function(path, bufnr)
-                path_wo_epp = path:sub(1,-5)
-                matched = vim.filetype.match({ buf = bufnr, filename = path_wo_epp })
+                local path_wo_epp = path:sub(1,-5)
+                local matched = vim.filetype.match({ buf = bufnr, filename = path_wo_epp })
                 if matched ~= nil and matched ~= 'mason' then
                     vim.b.epuppet_subtype = matched
                 end