Merge pull request #30740 from neikeq/typeinfo_static_fail

Make it a build error if a GetTypeInfo specialization cannot be resolved

core/type_info.h

@@ -83,15 +83,13 @@ enum Metadata {
 };
 }
 
+// If the compiler fails because it's trying to instantiate the primary 'GetTypeInfo' template
+// instead of one of the specializations, it's most likely because the type 'T' is not supported.
+// If 'T' is a class that inherits 'Object', make sure it can see the actual class declaration
+// instead of a forward declaration. You can always forward declare 'T' in a header file, and then
+// include the actual declaration of 'T' in the source file where 'GetTypeInfo<T>' is instantiated.
 template <class T, typename = void>
-struct GetTypeInfo {
-	static const Variant::Type VARIANT_TYPE = Variant::NIL;
-	static const GodotTypeInfo::Metadata METADATA = GodotTypeInfo::METADATA_NONE;
-	static inline PropertyInfo get_class_info() {
-		ERR_PRINT("GetTypeInfo fallback. Bug!");
-		return PropertyInfo(); // Not "Nil", this is an error
-	}
-};
+struct GetTypeInfo;
 
 #define MAKE_TYPE_INFO(m_type, m_var_type)                                            \
 	template <>                                                                       \
@@ -283,10 +281,7 @@ inline StringName __constant_get_enum_name(T param, const String &p_constant) {
 	return GetTypeInfo<T>::get_class_info().class_name;
 }
 
-#define CLASS_INFO(m_type)                                    \
-	(GetTypeInfo<m_type *>::VARIANT_TYPE != Variant::NIL ?    \
-					GetTypeInfo<m_type *>::get_class_info() : \
-					GetTypeInfo<m_type>::get_class_info())
+#define CLASS_INFO(m_type) (GetTypeInfo<m_type *>::get_class_info())
 
 #else