1 files changed, 21 insertions, 12 deletions

diff --git a/src/unique.hpp b/src/unique.hpp
index 846708e..829fa49 100644
--- a/src/unique.hpp
+++ b/src/unique.hpp
@@ -7,26 +7,39 @@ template <typename T, typename TAG, typename specialization = void>
 class Unique
 {
     private:
-    T val;
+    T val; // no default initialization so that std::is_trivial_v<Unique<T>> == true
 
     public:
     using type = T;
-    constexpr Unique() = default;
-    operator T() const { return val; }
-    Unique& operator=(T const&) = delete;
-    Unique& operator=(T&&) = delete;
-    explicit constexpr Unique(T b_)
+
+    ~Unique() = default;
+    constexpr explicit Unique(T b_)
     : val{ b_ }
     {
     }
+
+    // rule of 5
+    constexpr Unique() = default;
+    constexpr Unique(Unique const&) = default;
+    constexpr Unique(Unique&&) = default;
+    constexpr Unique& operator=(Unique const&) = default;
+    constexpr Unique& operator=(Unique&&) = default;
+
+    // can't implicitly affect from base type
+    Unique& operator=(T const&) = delete;
+    constexpr Unique& operator=(T&&) = delete;
+
+    // cast
+    constexpr operator T() const noexcept { return val; }
+
     // pre-increment
-    auto& operator++()
+    auto& operator++() noexcept
     {
         ++val;
         return *this;
     }
     // post-increment
-    auto operator++(int)
+    auto operator++(int) noexcept
     {
         return Unique<T, TAG>{ std::exchange(val, val + 1) };
     }
@@ -46,7 +59,3 @@ class Unique<T, TAG, std::enable_if_t<!std::is_scalar_v<T>>>
 };
 
 #define DECLARE_UNIQUE_TYPE(_name, _type) using _name = Unique<_type, class Unique_##_name##_Tag>
-
-// putting this here to break a header circular dependency until I find a better place
-DECLARE_UNIQUE_TYPE(StackIndex, int);
-static constexpr StackIndex kIdxTop{ -1 };