code: protected LightweightTypeReference toLightweightTypeReference(JvmFormalParameter parameter) {
  		JvmTypeReference parameterType = parameter.getParameterType();
  		if (parameterType == null) {
  			return null;
  		}
  		LightweightTypeReference result = owner.toLightweightTypeReference(parameterType);
  		return result;
  	}
docs: /* @Nullable