Casting an enum to Edm.String returns Int-value instead of enum label name

[SchlenkR]

Given the following filter:

$filter=contains(tolower(cast(MyEnumProperty, Edm.String)), 'EnumLabel1')

Executing the filter seems to convert the value of MyEnumProperty to the int-representation in form of a string.

This query then works (assuming "EnumLabel1" is represented by int-value 2:

$filter=contains(tolower(cast(MyEnumProperty, Edm.String)), '2')

Additional detail

Have a look at the else branch in FilterBinder.cs - BindCastToStringType(Expression source):

if (TypeHelper.IsGenericType(source.Type) && source.Type.GetGenericTypeDefinition() == typeof(Nullable<>))
{
	...
}
else
{
	sourceValue = TypeHelper.IsEnum(source.Type) ?
		Expression.Convert(source, Enum.GetUnderlyingType(source.Type)) :
		source;
	return Expression.Call(sourceValue, "ToString", typeArguments: null, arguments: null);
}

The Enum.GetUnderlyingType(source.Type) is Int32, which is passed to the convert function.

I'm not too familiar with the OData spec, but is it really the expected behavior, since on a lot of other places, enum label names are used instead of enum values.