types(model): make InsertManyResult consistent with return type of insertMany

Fix #13904

Author: vkarpov15

test/types/models.test.ts

@@ -9,6 +9,7 @@ import mongoose, {
   CallbackError,
   HydratedDocument,
   HydratedDocumentFromSchema,
+  InsertManyResult,
   Query,
   UpdateWriteOpResult,
   AggregateOptions,
@@ -709,3 +710,20 @@ async function gh13746() {
   expectType<ObjectId | undefined>(findOneAndUpdateRes.lastErrorObject?.upserted);
   expectType<OkType>(findOneAndUpdateRes.ok);
 }
+
+function gh13904() {
+  const schema = new Schema({ name: String });
+
+  interface ITest {
+    name?: string;
+  }
+  const Test = model<ITest>("Test", schema);
+
+  expectAssignable<Promise<InsertManyResult<ITest>>>(Test.insertMany(
+    [{ name: "test" }],
+    {
+      ordered: false,
+      rawResult: true
+    }
+  ));
+}

types/models.d.ts

@@ -375,7 +375,7 @@ declare module 'mongoose' {
       options: InsertManyOptions & { ordered: false; rawResult: true; }
     ): Promise<mongodb.InsertManyResult<Require_id<DocContents>> & {
       mongoose: {
-        validationErrors: Error[];
+        validationErrors: (CastError | Error.ValidatorError)[];
         results: Array<
           Error |
           Object |