fix(amplify-codegen): resolves the compilation error "Missing argument" in swift

packages/amplify-codegen-e2e-tests/schemas/modelgen/custom_type_with_model_reference.graphql

@@ -0,0 +1,16 @@
+type Product @model {
+  id: ID!
+  name: String!
+  price: Float!
+}
+
+type OrderSummary {
+  orderId: ID!
+  product: Product!
+  quantity: Int!
+}
+
+type Mutation {
+  createOrder(productId: ID!, quantity: Int!): OrderSummary
+    @function(name: "createOrder-${env}")
+}

packages/amplify-codegen-e2e-tests/src/__tests__/datastore-modelgen-ios.test.ts

@@ -3,6 +3,7 @@ import { deleteAmplifyProject, testCodegenModels } from '../codegen-tests-base';
 import * as path from 'path';
 
 const schema = 'modelgen/model_gen_schema_with_aws_scalars.graphql';
+const customTypeWithModelRefSchema = 'modelgen/custom_type_with_model_reference.graphql';
 
 describe('Datastore Modelgen tests - iOS', () => {
     let projectRoot: string;
@@ -22,4 +23,8 @@ describe('Datastore Modelgen tests - iOS', () => {
     it(`should generate files at overridden location`, async () => {
       await testCodegenModels(DEFAULT_IOS_CONFIG, projectRoot, schema, path.join('amplification', 'manufactured', 'models'));
     });
+
+    it(`should generate correct syntax for custom types referencing @model types`, async () => {
+      await testCodegenModels(DEFAULT_IOS_CONFIG, projectRoot, customTypeWithModelRefSchema);
+    });
 });

packages/appsync-modelgen-plugin/src/__tests__/visitors/appsync-swift-visitor.test.ts

@@ -1533,6 +1533,67 @@ describe('AppSyncSwiftVisitor', () => {
     `);
   });
 
+  it('should support custom types referencing @model types', () => {
+    const schema = /* GraphQL */ `
+      type Product @model {
+        id: ID!
+        name: String!
+        price: Float!
+      }
+
+      type OrderSummary {
+        orderId: ID!
+        product: Product!
+        quantity: Int!
+      }
+    `;
+
+    const visitorOrderSummary = getVisitor(schema, 'OrderSummary', CodeGenGenerateEnum.code);
+    expect(visitorOrderSummary.generate()).toMatchInlineSnapshot(`
+      "// swiftlint:disable all
+      import Amplify
+      import Foundation
+
+      public struct OrderSummary: Embeddable {
+        var orderId: String
+        var product: Product
+        var quantity: Int
+      }"
+    `);
+
+    const visitorOrderSummarySchema = getVisitor(schema, 'OrderSummary', CodeGenGenerateEnum.metadata);
+    expect(visitorOrderSummarySchema.generate()).toMatchInlineSnapshot(`
+      "// swiftlint:disable all
+      import Amplify
+      import Foundation
+
+      extension OrderSummary {
+        // MARK: - CodingKeys 
+         public enum CodingKeys: String, ModelKey {
+          case orderId
+          case product
+          case quantity
+        }
+
+        public static let keys = CodingKeys.self
+        //  MARK: - ModelSchema 
+
+        public static let schema = defineSchema { model in
+          let orderSummary = OrderSummary.keys
+
+          model.listPluralName = \\"OrderSummaries\\"
+          model.syncPluralName = \\"OrderSummaries\\"
+
+          model.fields(
+            .field(orderSummary.orderId, is: .required, ofType: .string),
+            .field(orderSummary.product, is: .required, ofType: .model(type: Product.self)),
+            .field(orderSummary.quantity, is: .required, ofType: .int)
+          )
+          }
+      }"
+    `);
+  });
+
   it('should escape swift reserved keywords in enum', () => {
     const schema = /* GraphQL */ `
       enum PostStatus {

packages/appsync-modelgen-plugin/src/visitors/appsync-swift-visitor.ts

@@ -662,7 +662,7 @@ export class AppSyncSwiftVisitor<
       if (isEnumType) {
         ofType = `.enum(type: ${typeName})`;
       } else if (isModelType) {
-        ofType = `.model(${typeName})`;
+        ofType = `.model(type: ${typeName})`;
       } else if (isNonModelType) {
         ofType = `.embedded(type: ${typeName})`;
       } else {