diff --git a/plugin/hmts.lua b/plugin/hmts.lua
index 8514070..d3fb1b9 100644
--- a/plugin/hmts.lua
+++ b/plugin/hmts.lua
@@ -154,6 +154,9 @@ end
 local function hmts_inject_handler(match, _, bufnr, predicate, metadata)
 	local path_node = match[predicate[2]]
 	local filename = find_filename_in_parent_node(path_node, bufnr)
+	if filename == nil then
+		return
+	end
 	local alias = vim.filetype.match({ filename = filename })
 
 	if alias == nil then