private void buildSimplifiedPrefixExpression(PsiPrefixExpression expression, StringBuilder out, CommentTracker tracker) {
    final PsiJavaToken sign = expression.getOperationSign();
    final IElementType tokenType = sign.getTokenType();
    final PsiExpression operand = expression.getOperand();
    if (JavaTokenType.EXCL.equals(tokenType)) {
      final Boolean value = evaluate(operand);
      if (value == Boolean.TRUE) {
        out.append(PsiKeyword.FALSE);
        return;
      }
      else if (value == Boolean.FALSE) {
        out.append(PsiKeyword.TRUE);
        return;
      }
    }
    buildSimplifiedExpression(operand, out.append(sign.getText()), tracker);
  }
private void buildSimplifiedPrefixExpression(PsiPrefixExpression expression, StringBuilder out, CommentTracker tracker)