Enums with custom value converter are converted to ints in $filter clause

[Xriuk]

This part:

AspNetCoreOData/src/Microsoft.AspNetCore.OData/Query/Expressions/ExpressionBinderHelper.cs

Lines 65 to 72 in 85944be

	// Convert to integers unless Enum type is required
	if ((TypeHelper.IsEnum(leftUnderlyingType) || TypeHelper.IsEnum(rightUnderlyingType)) && binaryOperator != BinaryOperatorKind.Has)
	{
	Type enumType = TypeHelper.IsEnum(leftUnderlyingType) ? leftUnderlyingType : rightUnderlyingType;
	Type enumUnderlyingType = Enum.GetUnderlyingType(enumType);
	left = ConvertToEnumUnderlyingType(left, enumType, enumUnderlyingType);
	right = ConvertToEnumUnderlyingType(right, enumType, enumUnderlyingType);
	}

Arbitrarily converts enums to integers, which may or might not be the desired effect.

I have a custom ValueConverter applied to an enum in EF Core, which causes them to be saved as a hash of the enum name instead of their enum value. So Type eq 'MyType' currently becomes (int)$it.Type == 1 which does not make sense for my case because it should be $it.Type == TypeEnum.MyType (which later will be translated by EF Core into something like (int)$it.Type == 123456789).

This makes even less sense considering that enums themselves support also comparison operators like >, >=, <, <=, ... so why this decision was even made in the first place?

I think enum handling or conversions should be left to the underlying IQueryable QueryProvider, EF Core in this case, OData expressions should be translated as they are.