Selecting int property into enum throws an exception

[Feroks]

Description

I have table with property A of type int. I need to dynamically select data and map to class that has property A, but is enum instead of int.

Exception

Exception message: Value cannot be null. Parameter name: expression.
Stack trace:
at System.Linq.Expressions.Expression.RequiresCanRead(Expression expression, String paramName)
at System.Linq.Expressions.Expression.Bind(MemberInfo member, Expression expression)
at System.Linq.Dynamic.Core.Parser.ExpressionParser.CreateNewExpression(List`1 properties, List`1 expressions, Type newType)
at System.Linq.Dynamic.Core.Parser.ExpressionParser.ParseNew()
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.ParseMultiplicative()
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.Select[TResult](IQueryable source, ParsingConfig config, String selector, Object[] args)
at System.Linq.Dynamic.Core.DynamicQueryableExtensions.Select[TResult](IQueryable source, String selector, Object[] args)

Reproduction

Here is .NET fiddle that reproduces the issue. It seems that problem occurs, because enum is considered to be a TypeCode.Object here:

System.Linq.Dynamic.Core/src/System.Linq.Dynamic.Core/Parser/TypeHelper.cs

Line 55 in 52d0831

TypeCode tc = tt.GetTypeInfo().IsEnum ? TypeCode.Object : Type.GetTypeCode(tt);

As a result, check below fails and returns null:

System.Linq.Dynamic.Core/src/System.Linq.Dynamic.Core/Parser/TypeHelper.cs

Lines 113 to 123 in 52d0831

	case TypeCode.Int32:
	switch (tc)
	{
	case TypeCode.Int32:
	case TypeCode.Int64:
	case TypeCode.Single:
	case TypeCode.Double:
	case TypeCode.Decimal:
	return true;
	}
	break;

[StefH]

A fix for this will be included in next version.