Fix memory leak

src/metric.cpp

@@ -668,7 +668,7 @@ struct Metric {
   };
 
   struct AggregateCounter {
-    std::vector<Counter::State *> thread_states;
+    std::span<Counter::State *const> thread_states;
     Counter::State *global_state;
   };
 
@@ -677,7 +677,7 @@ struct Metric {
   };
 
   struct AggregateHistogram {
-    std::vector<Histogram::State *> thread_states;
+    std::span<Histogram::State *const> thread_states;
     Histogram::State *global_state;
     size_t bucket_count;
     std::span<const double> buckets; // For bucket threshold formatting
@@ -724,26 +724,12 @@ struct Metric {
       new (&aggregate_histogram) AggregateHistogram(ah);
     }
 
-    // Destructor
-    ~RenderInstruction() {
-      switch (type) {
-      case InstructionType::CALL_COUNTER_CALLBACK:
-        counter_callback.~CallCounterCallback();
-        break;
-      case InstructionType::CALL_GAUGE_CALLBACK:
-        gauge_callback.~CallGaugeCallback();
-        break;
-      case InstructionType::AGGREGATE_COUNTER:
-        aggregate_counter.~AggregateCounter();
-        break;
-      case InstructionType::AGGREGATE_GAUGE:
-        aggregate_gauge.~AggregateGauge();
-        break;
-      case InstructionType::AGGREGATE_HISTOGRAM:
-        aggregate_histogram.~AggregateHistogram();
-        break;
-      }
-    }
+    // Destructor not needed, all instructions are trivially destructible
+    static_assert(std::is_trivially_destructible_v<CallCounterCallback>);
+    static_assert(std::is_trivially_destructible_v<CallGaugeCallback>);
+    static_assert(std::is_trivially_destructible_v<AggregateCounter>);
+    static_assert(std::is_trivially_destructible_v<AggregateGauge>);
+    static_assert(std::is_trivially_destructible_v<AggregateHistogram>);
 
     // Copy constructor and assignment
     RenderInstruction(const RenderInstruction &other) : type(other.type) {
@@ -769,9 +755,8 @@ struct Metric {
 
     RenderInstruction &operator=(const RenderInstruction &other) {
       if (this != &other) {
-        // Destroy current object
-        this->~RenderInstruction();
-        // Reconstruct with new type and data
+        // All union members are trivially destructible, so no need to call
+        // destructor. Just reconstruct with new type and data.
         type = other.type;
         switch (type) {
         case InstructionType::CALL_COUNTER_CALLBACK: