diff --git a/plugin/filetype.lua b/plugin/filetype.lua
index 0cd1150..3661b38 100644
--- a/plugin/filetype.lua
+++ b/plugin/filetype.lua
@@ -1,7 +1,8 @@
 vim.filetype.add({
   extension = {
     cl = 'opencl',
-    def = 'cpp',
+    def = 'cpp.def',
+    inc = 'cpp.inc',
     ll = 'llvm',
     md = 'markdown',
     ronn = 'markdown',