Issue with Where() method when filtering multiple string properties while using ToLower()

[LeoGrahamPAR]

1. Description

When using Where() and providing a string with either || or or, more than one property of type string, and using ToLower() on the string, the second string property is treated as a char.

(Name != null && Convert.ToString(Name).ToLower().Contains("someword")) or (Description != null && Convert.ToString(Description).ToLower().Contains("someword"))

In the example above, Name is of type string, and Description is of type string?, hence the null check. However, I have tested it with two non-nullable reference type strings.

The issue seems to occur primarily due to the use of ToLower(), as when removed, the code works as intended, excluding the case-insensitive search, regardless of the number of properties being searched via || or or.

An example of the code looks as follows:

var filterExpression = string
    .Join(" or ", filterableProperties.Select(propertyName => 
        $"({propertyName} != null && Convert.ToString({propertyName}).ToLower().Contains(\"{filterValue}\"))"));

return query.Where(filterExpression);

2. Exception

Exception message:
No property or field 'Description' exists in type 'Char' (at index 69)

Stack trace:
at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseMemberAccess(Type type, Expression expression, String id)
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseIdentifier()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParsePrimaryStart()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParsePrimary()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseUnary()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseArithmetic()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseAdditive()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseShiftOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseComparisonOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseLogicalAndOrOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseIn()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseAndOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseOrOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseLambdaOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseNullCoalescingOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseConditionalOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseParenExpression()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParsePrimaryStart()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParsePrimary()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseUnary()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseArithmetic()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseAdditive()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseShiftOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseComparisonOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseLogicalAndOrOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseIn()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseAndOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseOrOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseLambdaOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseNullCoalescingOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseConditionalOperator()
   at System.Linq.Dynamic.Core.Parser.ExpressionParser.Parse(Type resultType, Boolean createParameterCtor)
   at System.Linq.Dynamic.Core.DynamicExpressionParser.ParseLambda(Type delegateType, ParsingConfig parsingConfig, Boolean createParameterCtor, ParameterExpression[] parameters, Type resultType, String expression, Object[] values)
   at System.Linq.Dynamic.Core.DynamicExpressionParser.ParseLambda(ParsingConfig parsingConfig, Boolean createParameterCtor, ParameterExpression[] parameters, Type resultType, String expression, Object[] values)
   at System.Linq.Dynamic.Core.DynamicExpressionParser.ParseLambda(ParsingConfig parsingConfig, Boolean createParameterCtor, Type itType, Type resultType, String expression, Object[] values)
   at System.Linq.Dynamic.Core.DynamicQueryableExtensions.Where(IQueryable source, ParsingConfig config, String predicate, Object[] args)
   at System.Linq.Dynamic.Core.DynamicQueryableExtensions.Where[TSource](IQueryable`1 source, ParsingConfig config, String predicate, Object[] args)
   at System.Linq.Dynamic.Core.DynamicQueryableExtensions.Where[TSource](IQueryable`1 source, String predicate, Object[] args)

3. Fiddle or Project

Unavailable

4. Any further technical details

The intended use is to query an EF Core entity and be able to search multiple property types (strings, ints, etc.) by converting them to strings prior to comparing them to the filter value. If there are better ways to perform case-insensitive comparison of different property types using DynamicLinq, I'm open to suggestions.

[StefH]

Solved in #804

Linked : #811