IN operator not working with null value on nullable properties

[ghost]

An NullReferenceException is thrown while parsing a filter expression with the IN operator and a null value for a nullable property.

The problem seems to be related to this line of code:

odata.net/src/Microsoft.OData.Core/UriParser/SemanticAst/CollectionConstantNode.cs

Line 57 in eb0fc9a

this.collection.Add(new ConstantNode(item, item.ToString(), this.itemType));

If item is NULL, then the call to ToString() will fail with a NullReferenceException.

Assemblies affected

ODataLib 7.5.3

Reproduce steps

Sample Model

public class TestEntity
{
   [Key]
   public int PropertyKey { get; set; }

   public int PropertyInt { get; set; }

   public int? NullablePropertyInt { get; set; }
}

Sample query

http://host/service/TestEntity?$filter=NullablePropertyInt in (1,2,null)

Expected result

The list of all the TestEntity with 1, 2 or NULL as the value of the property NullablePropertyInt.

Actual result

An NullReferenceException is thrown:

System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.OData.UriParser.CollectionConstantNode..ctor(IEnumerable`1 objectCollection, String literalText, IEdmCollectionTypeReference collectionType)
   at Microsoft.OData.UriParser.LiteralBinder.BindLiteral(LiteralToken literalToken)
   at Microsoft.OData.UriParser.MetadataBinder.Bind(QueryToken token)
   at Microsoft.OData.UriParser.InBinder.GetCollectionOperandFromToken(QueryToken queryToken, IEdmTypeReference expectedType, IEdmModel model)
   at Microsoft.OData.UriParser.InBinder.BindInOperator(InToken inToken, BindingState state)
   at Microsoft.OData.UriParser.MetadataBinder.Bind(QueryToken token)
   at Microsoft.OData.UriParser.FilterBinder.BindFilter(QueryToken filter)
   at Microsoft.OData.UriParser.ODataQueryOptionParser.ParseFilterImplementation(String filter, ODataUriParserConfiguration configuration, ODataPathInfo odataPathInfo)
   at Microsoft.OData.UriParser.ODataQueryOptionParser.ParseFilter()

Additional detail

if we try the same query on the non nullable property, we are receiving an ODataException explaining the NULL value is not allowed, which is correct.

http://host/service/TestEntity?$filter=PropertyInt in (1,2,null)

Microsoft.OData.ODataException: A null value was found with the expected type 'Edm.Int32[Nullable=False]'. The expected type 'Edm.Int32[Nullable=False]' does not allow null values.
   at Microsoft.OData.ReaderValidationUtils.ThrowNullValueForNonNullableTypeException(IEdmTypeReference expectedValueTypeReference, String propertyName)
   at Microsoft.OData.ReaderValidationUtils.ValidateNullValueAllowed(IEdmTypeReference expectedValueTypeReference, Boolean validateNullValue, String propertyName, Nullable`1 isDynamicProperty)
   at Microsoft.OData.ReaderValidator.ValidateNullValue(IEdmTypeReference expectedTypeReference, Boolean validateNullValue, String propertyName, Nullable`1 isDynamicProperty)
   at Microsoft.OData.Json.ODataJsonReaderCoreUtils.TryReadNullValue(IJsonReader jsonReader, ODataInputContext inputContext, IEdmTypeReference expectedTypeReference, Boolean validateNullValue, String propertyName, Nullable`1 isDynamicProperty)
   at Microsoft.OData.JsonLight.ODataJsonLightPropertyAndValueDeserializer.ReadNonEntityValueImplementation(String payloadTypeName, IEdmTypeReference expectedTypeReference, PropertyAndAnnotationCollector propertyAndAnnotationCollector, CollectionWithoutExpectedTypeValidator collectionValidator, Boolean validateNullValue, Boolean isTopLevelPropertyValue, Boolean insideResourceValue, String propertyName, Nullable`1 isDynamicProperty)
   at Microsoft.OData.JsonLight.ODataJsonLightPropertyAndValueDeserializer.ReadCollectionValue(IEdmCollectionTypeReference collectionValueTypeReference, String payloadTypeName, ODataTypeAnnotation typeAnnotation)
   at Microsoft.OData.JsonLight.ODataJsonLightPropertyAndValueDeserializer.ReadNonEntityValueImplementation(String payloadTypeName, IEdmTypeReference expectedTypeReference, PropertyAndAnnotationCollector propertyAndAnnotationCollector, CollectionWithoutExpectedTypeValidator collectionValidator, Boolean validateNullValue, Boolean isTopLevelPropertyValue, Boolean insideResourceValue, String propertyName, Nullable`1 isDynamicProperty)
   at Microsoft.OData.ODataUriConversionUtils.ConvertFromResourceOrCollectionValue(String value, IEdmModel model, IEdmTypeReference typeReference)
   at Microsoft.OData.UriParser.InBinder.GetCollectionOperandFromToken(QueryToken queryToken, IEdmTypeReference expectedType, IEdmModel model)
   at Microsoft.OData.UriParser.InBinder.BindInOperator(InToken inToken, BindingState state)
   at Microsoft.OData.UriParser.MetadataBinder.Bind(QueryToken token)
   at Microsoft.OData.UriParser.FilterBinder.BindFilter(QueryToken filter)
   at Microsoft.OData.UriParser.ODataQueryOptionParser.ParseFilterImplementation(String filter, ODataUriParserConfiguration configuration, ODataPathInfo odataPathInfo)
   at Microsoft.OData.UriParser.ODataQueryOptionParser.ParseFilter()