message: fix: fix crash when discriminator is used incorrectly
diff: @@ -198,6 +198,7 @@ export class SpecManager {
  let definition = schema || this.byPointer(defPointer);
  if (!definition) throw new Error(`Can't load schema at ${defPointer}`);
  if (!definition.discriminator && !definition['x-extendedDiscriminator']) return [];
  + if (defPointer === undefined) return [];
  let globalDefs = this._schema.definitions || {};
  let res:DescendantInfo[] = [];
  