private static void checkForSecondUnsafeCall(GrExpression expression, ProblemsHolder holder, @Nullable PsiElement highlightElement) {
    if (highlightElement == null) highlightElement = expression;

    final GrReferenceExpression referenceExpression = (GrReferenceExpression)expression;

    if (GroovyTokenTypes.mDOT.equals(referenceExpression.getDotTokenType())) {
      if (isNullableQualifier(referenceExpression.getQualifierExpression())) {
        holder.registerProblem(highlightElement, GroovyBundle.message("call.can.throw.npe"), new SecondUnsafeCallQuickFix());
      }
    }
  }
private static void checkForSecondUnsafeCall(GrExpression expression, ProblemsHolder holder, @Nullable PsiElement highlightElement)