@Nullable
      private Object computeConstant(PsiExpression expression) {
        if (expression.getTextLength() > MAX_EXPRESSION_LENGTH) return null;
        if (expression.getType() == null) return null;
        Object value = computeValue(expression);
        if (value == null) return null;
        final PsiExpression parent = getParentExpression(expression);
        if (parent != null && computeValue(parent) != null) return null;
        return value;
      }
@Nullable
      private Object computeConstant(PsiExpression expression)