Fixed packet compression

test/SQL2Test.cpp

@@ -7,6 +7,7 @@
 #include <cassert>
 #include <sql/SqlQuery.h>
 
+#if 0
 template <typename T>
 struct Column {
     constexpr explicit Column(const std::string_view& name) : name{name} { }
@@ -166,4 +167,23 @@ int main() {
     std::string value{};
     insert.add_entry(2, value);
     insert.execute(nullptr);
+}
+#endif
+
+struct A {
+    A() {}
+    ~A() = default;
+};
+
+#include <set>
+int main() {
+    std::set<int> elements{};
+    if(!elements.empty()) {
+        auto it = elements.begin();
+        const int* last_element{&*(it++)}; /* if elements would be empty this would be undefined behaviour */
+        while(it != elements.end()) {
+            const auto now = *it++;
+            const auto diff = last_element - now;
+        }
+    }
 }