Require types used with construct are trivially destructible

tests/test_arena_allocator.cpp

@@ -1,5 +1,6 @@
 #define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
 #include "arena_allocator.hpp"
+#include <cstring>
 #include <doctest/doctest.h>
 #include <string>
 #include <vector>
@@ -106,10 +107,17 @@ TEST_CASE("ArenaAllocator construct template") {
     CHECK(*ptr == 42);
   }
 
-  SUBCASE("construct string") {
-    std::string *ptr = arena.construct<std::string>("hello world");
+  SUBCASE("construct array") {
+    struct FixedString {
+      char data[16];
+      FixedString(const char *str) {
+        std::strncpy(data, str, sizeof(data) - 1);
+        data[sizeof(data) - 1] = '\0';
+      }
+    };
+    FixedString *ptr = arena.construct<FixedString>("hello world");
     CHECK(ptr != nullptr);
-    CHECK(*ptr == "hello world");
+    CHECK(std::strcmp(ptr->data, "hello world") == 0);
   }
 
   SUBCASE("construct multiple objects") {
@@ -122,10 +130,15 @@ TEST_CASE("ArenaAllocator construct template") {
   }
 
   SUBCASE("construct with multiple arguments") {
-    auto *ptr = arena.construct<std::pair<int, std::string>>(42, "test");
+    struct IntPair {
+      int first;
+      int second;
+      IntPair(int a, int b) : first(a), second(b) {}
+    };
+    auto *ptr = arena.construct<IntPair>(42, 24);
     CHECK(ptr != nullptr);
     CHECK(ptr->first == 42);
-    CHECK(ptr->second == "test");
+    CHECK(ptr->second == 24);
   }
 }
 
@@ -266,27 +279,29 @@ TEST_CASE("ArenaAllocator edge cases") {
   }
 }
 
-struct TestObject {
+struct TestPOD {
   int value;
-  std::string name;
+  char name[16];
 
-  TestObject(int v, const std::string &n) : value(v), name(n) {}
-  ~TestObject() = default;
+  TestPOD(int v, const char *n) : value(v) {
+    std::strncpy(name, n, sizeof(name) - 1);
+    name[sizeof(name) - 1] = '\0';
+  }
 };
 
 TEST_CASE("ArenaAllocator with custom objects") {
   ArenaAllocator arena;
 
-  TestObject *obj1 = arena.construct<TestObject>(42, "first");
-  TestObject *obj2 = arena.construct<TestObject>(84, "second");
+  TestPOD *obj1 = arena.construct<TestPOD>(42, "first");
+  TestPOD *obj2 = arena.construct<TestPOD>(84, "second");
 
   CHECK(obj1 != nullptr);
   CHECK(obj2 != nullptr);
   CHECK(obj1 != obj2);
   CHECK(obj1->value == 42);
-  CHECK(obj1->name == "first");
+  CHECK(std::strcmp(obj1->name, "first") == 0);
   CHECK(obj2->value == 84);
-  CHECK(obj2->name == "second");
+  CHECK(std::strcmp(obj2->name, "second") == 0);
 }
 
 TEST_CASE("ArenaAllocator geometric growth policy") {