anchor.diff:        new GraphQLNonNullableType<Value, Serialized>._(this);
   }
   
  +/// A special [GraphQLType] that indicates that input values should both be non-null, and be valid when asserted against another type, named [ofType].
   class GraphQLNonNullableType<Value, Serialized>
       extends GraphQLType<Value, Serialized> {
     final GraphQLType<Value, Serialized> ofType;
  
positive.code:         GraphQLType<Value, Serialized> innerType) =>
      new GraphQLListType<Value, Serialized>(innerType);
  
  class GraphQLListType<Value, Serialized>
      extends GraphQLType<List<Value>, List<Serialized>>
      with _NonNullableMixin<List<Value>, List<Serialized>> {
  
negative.code: part of graphql_schema.src.schema;
  
  /// Strictly dictates the structure of some input data in a GraphQL query.
  ///
  /// GraphQL's rigid type system is primarily implemented in Dart using classes that extend from [GraphQLType].
  ///
  /// A [GraphQLType] represents values of type [Value] as values of type [Serialized]; for example, a
  /// [GraphQLType] that serializes objects into `String`s.
  abstract class GraphQLType<Value, Serialized> {
    /// The name of this type.
    String get name;
  
    /// A description of this type, which, while optional, can be very useful in tools like GraphiQL.
    String get description;
  
    /// Serializes an arbitrary input value.
    Serialized serialize(Value value);
  
    /// Deserializes a serialized value.
    Value deserialize(Serialized serialized);
  
    /// Performs type coercion against an [input] value, and returns a list of errors if the validation was unsuccessful.
    ValidationResult<Serialized> validate(String key, Serialized input);
  
    /// Creates a non-nullable type that represents this type, and enforces that a field of this type is present in input data.
    GraphQLType<Value, Serialized> nonNullable();
  
    /// Turns this type into one suitable for being provided as an input to a [GraphQLObjectField].
    GraphQLType<Value, Serialized> coerceToInputObject();
  
    @override
  