diff --git a/user.h b/user.h
index 2f1f1b9..b399930 100644
--- a/user.h
+++ b/user.h
@@ -4,17 +4,17 @@
 
 #include <string>
 #include <set>
+#include <vector>
 
 #include <nlohmann/json.hpp>
-#include <vector>
 
 namespace fs = std::filesystem;
 using json = nlohmann::json;
 
 template <typename T>
-static const bool ptr_cmp = [](T* left, T* right) { return *left < *right; };
+static const bool ptr_cmp(T* left, T* right) { return *left < *right; };
 
-typedef std::set<mail*, decltype(ptr_cmp<mail*>)> maillist;
+typedef std::set<mail*, decltype(ptr_cmp<mail*>)*> maillist;
 
 class user {
 public: