AK+LibWasm+LibJS: Disallow Variant.has() on types that aren't contained

Checking for this (and get()'ing it) is always invalid, so let's just
disallow it.
This also finds two bugs where the code is checking for types that can
never actually be in the variant (which was actually a refactor
artifact).

1 files changed, 13 insertions, 13 deletions

diff --git a/AK/Variant.h b/AK/Variant.h
index 3475143793..af6b649105 100644
--- a/AK/Variant.h
+++ b/AK/Variant.h
@@ -201,6 +201,12 @@ private:
     static constexpr IndexType index_of() { return Detail::index_of<T, IndexType, Ts...>(); }
 
 public:
+    template<typename T>
+    static constexpr bool can_contain()
+    {
+        return index_of<T>() != invalid_index;
+    }
+
     template<typename... NewTs>
     friend struct Variant;
 
@@ -246,7 +252,7 @@ public:
     using Detail::MergeAndDeduplicatePacks<Detail::VariantConstructors<Ts, Variant<Ts...>>...>::MergeAndDeduplicatePacks;
 
     template<typename T, typename StrippedT = RemoveCV<RemoveReference<T>>>
-    void set(T&& t) requires(index_of<StrippedT>() != invalid_index)
+    void set(T&& t) requires(can_contain<StrippedT>())
     {
         constexpr auto new_index = index_of<StrippedT>();
         Helper::delete_(m_index, m_data);
@@ -255,7 +261,7 @@ public:
     }
 
     template<typename T, typename StrippedT = RemoveCV<RemoveReference<T>>>
-    void set(T&& t, Detail::VariantNoClearTag) requires(index_of<StrippedT>() != invalid_index)
+    void set(T&& t, Detail::VariantNoClearTag) requires(can_contain<StrippedT>())
     {
         constexpr auto new_index = index_of<StrippedT>();
         new (m_data) StrippedT(forward<T>(t));
@@ -263,7 +269,7 @@ public:
     }
 
     template<typename T>
-    T* get_pointer()
+    T* get_pointer() requires(can_contain<T>())
     {
         if (index_of<T>() == m_index)
             return bit_cast<T*>(&m_data);
@@ -271,14 +277,14 @@ public:
     }
 
     template<typename T>
-    T& get()
+    T& get() requires(can_contain<T>())
     {
         VERIFY(has<T>());
         return *bit_cast<T*>(&m_data);
     }
 
     template<typename T>
-    const T* get_pointer() const
+    const T* get_pointer() const requires(can_contain<T>())
     {
         if (index_of<T>() == m_index)
             return bit_cast<const T*>(&m_data);
@@ -286,14 +292,14 @@ public:
     }
 
     template<typename T>
-    const T& get() const
+    const T& get() const requires(can_contain<T>())
     {
         VERIFY(has<T>());
         return *bit_cast<const T*>(&m_data);
     }
 
     template<typename T>
-    [[nodiscard]] bool has() const
+    [[nodiscard]] bool has() const requires(can_contain<T>())
     {
         return index_of<T>() == m_index;
     }
@@ -336,12 +342,6 @@ public:
         return instance;
     }
 
-    template<typename T>
-    static constexpr bool can_contain()
-    {
-        return index_of<T>() != invalid_index;
-    }
-
 private:
     static constexpr auto data_size = integer_sequence_generate_array<size_t>(0, IntegerSequence<size_t, sizeof(Ts)...>()).max();
     static constexpr auto data_alignment = integer_sequence_generate_array<size_t>(0, IntegerSequence<size_t, alignof(Ts)...>()).max();