Error for FAttachmentTransformRules

My contructor look like this now

 // Sets default values
    AKillerBase::AKillerBase() : AttachRules(EAttachmentRule::KeepRelative, true)
    {
     	// Set this character to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
    	PrimaryActorTick.bCanEverTick = true;

But I’m still getting the same error. Did I do something wrong?

‘FAttachmentTransformRules’: no
appropriate default constructor
available