Compile error going from 5.4 to 5.5

[Undead_Studios]

Hi all,

Getting this error when trying to compile for 5.5

1>E:\Unreal\Engine\UE_5.5\Engine\Source\Runtime\CoreUObject\Public\Templates\Casts.h(126): error C2338: static_assert failed: ‘Attempting to use Cast<> on a type that is not a UObject or an Interface’
1>E:\Unreal\Engine\UE_5.5\Engine\Source\Runtime\CoreUObject\Public\Templates\Casts.h(126): note: the template instantiation context (the oldest one first) is
1>E:\Unreal\RPG_5.4\Plugins\CISQLite3\Source\CISQLite3\Private\SQLiteDatabase.cpp(840): note: see reference to function template instantiation ‘To *Cast<FInt64Property,FProperty>(From *)’ being compiled
1> with
1> [
1> To=FInt64Property,
1> From=FProperty
1> ]

the line in question is :

if ((int64prop = Cast(targetProperty)) != NULL)

and the function in total is :

void USQLiteDatabase::AssignResultsToObjectProperties(const SQLiteResultValue& ResultValue, UObject* ObjectToPopulate)
{
auto propertyMap = CollectProperties(ObjectToPopulate);
for (SQLiteResultField field : ResultValue.Fields)
{
if (propertyMap.Contains(field.Name))
{
FProperty* targetProperty = propertyMap[field.Name];

		if (field.Type == SQLiteResultValueTypes::Integer)
		{
			FInt64Property* int64prop = NULL;
			FIntProperty* int32prop = NULL;
			FInt16Property* int16prop = NULL;
			FInt8Property* int8prop = NULL;
			FBoolProperty* boolProp = NULL;

			if ((int64prop = Cast<FInt64Property>(targetProperty)) != NULL)
			{
				int64prop->SetPropertyValue_InContainer(ObjectToPopulate, field.IntValue);
				LOGSQLITE(Verbose, *FString::Printf(TEXT("Property '%s' was set to '%d'"), *field.Name, field.IntValue));
			}
			else if ((int32prop = Cast<FIntProperty>(targetProperty)) != NULL)
			{
				int32prop->SetPropertyValue_InContainer(ObjectToPopulate, (int32)field.IntValue);
				LOGSQLITE(Verbose, *FString::Printf(TEXT("Property '%s' was set to '%d'"), *field.Name, field.IntValue));
			}
			else if ((int16prop = Cast<FInt16Property>(targetProperty)) != NULL)
			{
				int16prop->SetPropertyValue_InContainer(ObjectToPopulate, (int16)field.IntValue);
				LOGSQLITE(Verbose, *FString::Printf(TEXT("Property '%s' was set to '%d'"), *field.Name, field.IntValue));
			}
			else if ((int8prop = Cast<FInt8Property>(targetProperty)) != NULL)
			{
				int8prop->SetPropertyValue_InContainer(ObjectToPopulate, (int8)field.IntValue);
				LOGSQLITE(Verbose, *FString::Printf(TEXT("Property '%s' was set to '%d'"), *field.Name, field.IntValue));
			}
			else if ((boolProp = Cast<FBoolProperty>(targetProperty)) != NULL)
			{
				boolProp->SetPropertyValue_InContainer(ObjectToPopulate, field.IntValue > 0);
				LOGSQLITE(Verbose, *FString::Printf(TEXT("Property '%s' was set to '%d'"), *field.Name, field.IntValue));
			}
		}

		else if (field.Type == SQLiteResultValueTypes::Float)
		{
			FDoubleProperty* doubleProp = NULL;
			FFloatProperty* floatProp = NULL;
			if ((doubleProp = Cast<FDoubleProperty>(targetProperty)) != NULL)
			{
				doubleProp->SetPropertyValue_InContainer(ObjectToPopulate, field.DoubleValue);
				LOGSQLITE(Verbose, *FString::Printf(TEXT("Property '%s' was set to '%f'"), *field.Name, field.DoubleValue));
			}
			else if ((floatProp = Cast<FFloatProperty>(targetProperty)) != NULL)
			{
				floatProp->SetPropertyValue_InContainer(ObjectToPopulate, (float)field.DoubleValue);
				LOGSQLITE(Verbose, *FString::Printf(TEXT("Property '%s' was set to '%f'"), *field.Name, field.DoubleValue));
			}
		}

		else if (field.Type == SQLiteResultValueTypes::Text)
		{
			FStrProperty* strProp = NULL;
			if ((strProp = Cast<FStrProperty>(targetProperty)) != NULL)
			{
				strProp->SetPropertyValue_InContainer(ObjectToPopulate, field.StringValue);
				LOGSQLITE(Verbose, *FString::Printf(TEXT("Property '%s' was set to '%s'"), *field.Name, *field.StringValue.Mid(0, 64)));
			}
		}

	}
}

}

Any help please

[Kollektorr]

As it stated in the error, you cannot use Cast<> if type is not derived from UObject or an Interface
“Attempting to use Cast<> on a type that is not a UObject or an Interface”

You can use CastField<> instead of Cast<> if you want to cast from FProperty to FInt64Property.

I tried like this and there is no compile error:

FProperty* targetProperty = NULL;
FInt64Property* int64prop = NULL;
int64prop = CastField<FInt64Property>(targetProperty);

Also I suggest you to follow Unreal’s official coding standards to have more readable code. With this way, everyone understand your code easily since everyone get used to this style around here
You can find the documentation Unreal Coding Standard

Have a good day!

[Undead_Studios]

Thankyou, this fixed the problem