@Override
 public void visitPolyadicExpression(PsiPolyadicExpression expression) {
   super.visitPolyadicExpression(expression);
   if (!ExpressionUtils.hasStringType(expression)) {
     return;
   }
   final PsiExpression[] operands = expression.getOperands();
   for (PsiExpression operand : operands) {
     checkExpression(operand);
   }
 }
 @Override
 public void visitPolyadicExpression(PsiPolyadicExpression expression) {
   super.visitPolyadicExpression(expression);
   checkExpression(expression);
 }