From bf599fa8d13f01b3db4e6e1b4b4af63d8ea2df4c Mon Sep 17 00:00:00 2001
From: Mary Gao <yanmeigao1210@gmail.com>
Date: Tue, 5 Mar 2024 16:02:46 +0800
Subject: [PATCH 1/6] Update the changes

---
 packages/typespec-ts/src/utils/modelUtils.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/typespec-ts/src/utils/modelUtils.ts b/packages/typespec-ts/src/utils/modelUtils.ts
index 48200666c2..dd0af7ebb0 100644
--- a/packages/typespec-ts/src/utils/modelUtils.ts
+++ b/packages/typespec-ts/src/utils/modelUtils.ts
@@ -229,7 +229,8 @@ export function getSchemaForType(
   return undefined;
 }
 export function getEffectiveModelFromType(program: Program, type: Type): Type {
-  if (type.kind === "Model") {
+  // Only adopt the logic from getEffectiveModelType when it is anonymous model
+  if (type.kind === "Model" && type.name === "") {
     const effective = getEffectiveModelType(program, type, isSchemaProperty);
     if (effective.name) {
       return effective;

From 7da5598661c18ce621b86b61e77aa4b0e598f7b3 Mon Sep 17 00:00:00 2001
From: Mary Gao <yanmeigao1210@gmail.com>
Date: Tue, 5 Mar 2024 19:06:10 +0800
Subject: [PATCH 2/6] Only adopt the getEffectiveModelType for anonymous model

---
 .../typespec-ts/src/modular/buildCodeModel.ts | 13 ++++++---
 packages/typespec-ts/src/utils/modelUtils.ts  |  5 +++-
 .../typespec-ts/test/modularUnit/type.spec.ts | 27 +++++++++++++++++-
 .../test/unit/modelsGenerator.spec.ts         | 28 +++++++++++++++++++
 4 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/packages/typespec-ts/src/modular/buildCodeModel.ts b/packages/typespec-ts/src/modular/buildCodeModel.ts
index 33e66b9d7f..7bd0c73eac 100644
--- a/packages/typespec-ts/src/modular/buildCodeModel.ts
+++ b/packages/typespec-ts/src/modular/buildCodeModel.ts
@@ -251,20 +251,25 @@ function getEffectiveSchemaType(program: Program, type: Model | Union): Model {
     return !(headerInfo || queryInfo || pathInfo || statusCodeinfo);
   }
 
-  let effective: Model;
+  // If type is an anonymous model, tries to find a named model that has the same properties
+  let effective: Model | undefined = undefined;
   if (type.kind === "Union") {
     const nonNullOptions = [...type.variants.values()]
       .map((x) => x.type)
       .filter((t) => !isNullType(t));
-    if (nonNullOptions.length === 1 && nonNullOptions[0]?.kind === "Model") {
+    if (
+      nonNullOptions.length === 1 &&
+      nonNullOptions[0]?.kind === "Model" &&
+      nonNullOptions[0]?.name === ""
+    ) {
       effective = getEffectiveModelType(program, nonNullOptions[0]);
     }
     return type as any;
-  } else {
+  } else if (type.name === "") {
     effective = getEffectiveModelType(program, type, isSchemaProperty);
   }
 
-  if (effective.name) {
+  if (effective?.name) {
     return effective;
   }
   return type as Model;
diff --git a/packages/typespec-ts/src/utils/modelUtils.ts b/packages/typespec-ts/src/utils/modelUtils.ts
index dd0af7ebb0..5d74c41fe4 100644
--- a/packages/typespec-ts/src/utils/modelUtils.ts
+++ b/packages/typespec-ts/src/utils/modelUtils.ts
@@ -229,7 +229,10 @@ export function getSchemaForType(
   return undefined;
 }
 export function getEffectiveModelFromType(program: Program, type: Type): Type {
-  // Only adopt the logic from getEffectiveModelType when it is anonymous model
+  /**
+   * If type is an anonymous model, tries to find a named model that has the same
+   * set of properties when non-schema properties are excluded.
+   */
   if (type.kind === "Model" && type.name === "") {
     const effective = getEffectiveModelType(program, type, isSchemaProperty);
     if (effective.name) {
diff --git a/packages/typespec-ts/test/modularUnit/type.spec.ts b/packages/typespec-ts/test/modularUnit/type.spec.ts
index 6b20d5d491..11d8b1a9b6 100644
--- a/packages/typespec-ts/test/modularUnit/type.spec.ts
+++ b/packages/typespec-ts/test/modularUnit/type.spec.ts
@@ -18,7 +18,7 @@ describe("model type", () => {
         export interface Test {
           color: "red" | "blue";
         }`
-      ); 
+      );
     });
 
     it("string enum member", async () => {
@@ -150,4 +150,29 @@ describe("model type", () => {
       );
     });
   });
+
+  describe("`is`", () => {
+    it("should generate correct name and properties if A is B<Template>", async () => {
+      const modelFile = await emitModularModelsFromTypeSpec(`
+      model B<Parameter> {
+        prop1: string;
+        prop2: Parameter;
+      }
+      model A is B<string> {
+        @query
+        name: string;
+      };
+        op read(@body body: A): void;
+        `);
+      assert.ok(modelFile);
+      await assertEqualContent(
+        modelFile!.getFullText()!,
+        `
+        export interface A {
+          prop1: string;
+          prop2: string;
+        }`
+      );
+    });
+  });
 });
diff --git a/packages/typespec-ts/test/unit/modelsGenerator.spec.ts b/packages/typespec-ts/test/unit/modelsGenerator.spec.ts
index de5c53f99f..1f2b2e1781 100644
--- a/packages/typespec-ts/test/unit/modelsGenerator.spec.ts
+++ b/packages/typespec-ts/test/unit/modelsGenerator.spec.ts
@@ -2312,6 +2312,34 @@ describe("Input/output model type", () => {
         outputType: `${inputModelName}`
       });
     });
+    it("should generate correct name and properties if A `is` B with template arguments", async () => {
+      const tspDefinition = `
+      model B<Parameter> {
+        prop1: string;
+        prop2: Parameter;
+      }
+      model A is B<string> {
+        @query
+        name: string;
+      };
+      `;
+      const tspType = "A";
+      const inputModelName = "A";
+      await verifyPropertyType(tspType, inputModelName, {
+        additionalTypeSpecDefinition: tspDefinition,
+        outputType: `${inputModelName}Output`,
+        additionalInputContent: `
+        export interface ${inputModelName} {
+          prop1:string;
+          prop2:string;
+        }`,
+        additionalOutputContent: `
+        export interface ${inputModelName}Output {
+          prop1:string;
+          prop2:string;
+        }`
+      });
+    });
   });
 
   describe("@projectedName", () => {

From ea4533e7904120eaae40df8cd4d20194aa437650 Mon Sep 17 00:00:00 2001
From: Mary Gao <yanmeigao1210@gmail.com>
Date: Tue, 5 Mar 2024 19:15:13 +0800
Subject: [PATCH 3/6] Only Enable readonly when the visibility is only read in
 modular

---
 .../typespec-ts/src/modular/buildCodeModel.ts |  2 +-
 .../test/modularUnit/modelsGenerator.spec.ts  | 73 +++++++++++++++++--
 .../typespec-ts/test/modularUnit/type.spec.ts | 25 -------
 3 files changed, 68 insertions(+), 32 deletions(-)

diff --git a/packages/typespec-ts/src/modular/buildCodeModel.ts b/packages/typespec-ts/src/modular/buildCodeModel.ts
index 7bd0c73eac..c730ec7d7b 100644
--- a/packages/typespec-ts/src/modular/buildCodeModel.ts
+++ b/packages/typespec-ts/src/modular/buildCodeModel.ts
@@ -951,7 +951,7 @@ function isReadOnly(program: Program, type: ModelProperty): boolean {
   // Only "read" should be readOnly
   const visibility = getVisibility(program, type);
   if (visibility) {
-    return visibility.includes("read");
+    return visibility.includes("read") && visibility.length === 1;
   } else {
     return false;
   }
diff --git a/packages/typespec-ts/test/modularUnit/modelsGenerator.spec.ts b/packages/typespec-ts/test/modularUnit/modelsGenerator.spec.ts
index 4218603eab..d67b07bf74 100644
--- a/packages/typespec-ts/test/modularUnit/modelsGenerator.spec.ts
+++ b/packages/typespec-ts/test/modularUnit/modelsGenerator.spec.ts
@@ -1778,9 +1778,8 @@ describe("inheritance & polymorphism", () => {
         true
       );
       assert.isUndefined(schemaOutput);
-      const paramOutput = await emitModularOperationsFromTypeSpec(
-        tspDefinition
-      );
+      const paramOutput =
+        await emitModularOperationsFromTypeSpec(tspDefinition);
       assert.ok(paramOutput);
       assert.strictEqual(paramOutput?.length, 1);
       await assertEqualContent(
@@ -1854,10 +1853,9 @@ describe("inheritance & polymorphism", () => {
         | "text/plain; charset=utf-8"
         | "text/vnd.ms.protobuf";
         `
-      )
-      const paramOutput = await emitModularOperationsFromTypeSpec(
-        tspDefinition
       );
+      const paramOutput =
+        await emitModularOperationsFromTypeSpec(tspDefinition);
       assert.ok(paramOutput);
       assert.strictEqual(paramOutput?.length, 1);
       await assertEqualContent(
@@ -1954,3 +1952,66 @@ describe("inheritance & polymorphism", () => {
     });
   });
 });
+
+describe("`is`", () => {
+  it("should generate correct name and properties if A is B<Template>", async () => {
+    const modelFile = await emitModularModelsFromTypeSpec(`
+    model B<Parameter> {
+      prop1: string;
+      prop2: Parameter;
+    }
+    model A is B<string> {
+      @query
+      name: string;
+    };
+      op read(@body body: A): void;
+      `);
+    assert.ok(modelFile);
+    await assertEqualContent(
+      modelFile!.getFullText()!,
+      `
+      export interface A {
+        prop1: string;
+        prop2: string;
+      }`
+    );
+  });
+});
+
+describe("visibility", () => {
+  it("should generate readonly for @visibility('read')", async () => {
+    const modelFile = await emitModularModelsFromTypeSpec(`
+      model A  {
+        @visibility("read")
+        exactVersion?: string;
+      };
+      op read(@body body: A): void;
+      `);
+    assert.ok(modelFile);
+    await assertEqualContent(
+      modelFile!.getFullText()!,
+      `
+      export interface A {
+        readonly exactVersion?: string;
+      }`
+    );
+  });
+
+  it("should not generate readonly for @visibility('read', 'create')", async () => {
+    const modelFile = await emitModularModelsFromTypeSpec(`
+      model A  {
+        @visibility("read", "create")
+        exactVersion?: string;
+      };
+      op read(@body body: A): void;
+      `);
+    assert.ok(modelFile);
+    await assertEqualContent(
+      modelFile!.getFullText()!,
+      `
+      export interface A {
+        exactVersion?: string;
+      }`
+    );
+  });
+});
diff --git a/packages/typespec-ts/test/modularUnit/type.spec.ts b/packages/typespec-ts/test/modularUnit/type.spec.ts
index 11d8b1a9b6..b0e4ca7727 100644
--- a/packages/typespec-ts/test/modularUnit/type.spec.ts
+++ b/packages/typespec-ts/test/modularUnit/type.spec.ts
@@ -150,29 +150,4 @@ describe("model type", () => {
       );
     });
   });
-
-  describe("`is`", () => {
-    it("should generate correct name and properties if A is B<Template>", async () => {
-      const modelFile = await emitModularModelsFromTypeSpec(`
-      model B<Parameter> {
-        prop1: string;
-        prop2: Parameter;
-      }
-      model A is B<string> {
-        @query
-        name: string;
-      };
-        op read(@body body: A): void;
-        `);
-      assert.ok(modelFile);
-      await assertEqualContent(
-        modelFile!.getFullText()!,
-        `
-        export interface A {
-          prop1: string;
-          prop2: string;
-        }`
-      );
-    });
-  });
 });

From 4c71fa17dce6efd689507348c81652f01c8b25d8 Mon Sep 17 00:00:00 2001
From: Mary Gao <yanmeigao1210@gmail.com>
Date: Wed, 6 Mar 2024 10:40:19 +0800
Subject: [PATCH 4/6] Re-generate smoke testing

---
 .../generated/typespec-ts/src/outputModels.ts    |  8 ++++++++
 .../generated/typespec-ts/src/responses.ts       | 16 ++++++++--------
 .../generated/typespec-ts/src/api/operations.ts  |  5 ++++-
 .../generated/typespec-ts/src/models/models.ts   |  4 ++--
 .../generated/typespec-ts/src/outputModels.ts    |  8 ++++++++
 .../generated/typespec-ts/src/responses.ts       | 14 ++++++++------
 6 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/src/outputModels.ts b/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/src/outputModels.ts
index c6590b313b..5611e2155f 100644
--- a/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/src/outputModels.ts
+++ b/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/src/outputModels.ts
@@ -257,6 +257,14 @@ export interface MultivariateCorrelationChangesOutput {
   changedVariables?: string[];
 }
 
+/** Error response */
+export interface MultivariateResponseErrorOutput {
+  /** The error code. */
+  code: string;
+  /** The message explaining the error reported by the service. */
+  message: string;
+}
+
 /**
  * Training result of a model including its status, errors and diagnostics
  * information.
diff --git a/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/src/responses.ts b/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/src/responses.ts
index 4e65770593..8b680449ab 100644
--- a/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/src/responses.ts
+++ b/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/src/responses.ts
@@ -9,7 +9,7 @@ import {
   UnivariateUnivariateLastDetectionResultOutput,
   UnivariateUnivariateChangePointDetectionResultOutput,
   MultivariateMultivariateDetectionResultOutput,
-  MultivariateErrorResponseOutput,
+  MultivariateResponseErrorOutput,
   MultivariateAnomalyDetectionModelOutput,
   MultivariateModelListOutput,
   MultivariateMultivariateLastDetectionResultOutput,
@@ -83,7 +83,7 @@ export interface GetMultivariateBatchDetectionResultDefaultHeaders {
 export interface GetMultivariateBatchDetectionResultDefaultResponse
   extends HttpResponse {
   status: string;
-  body: MultivariateErrorResponseOutput;
+  body: MultivariateResponseErrorOutput;
   headers: RawHttpHeaders & GetMultivariateBatchDetectionResultDefaultHeaders;
 }
 
@@ -106,7 +106,7 @@ export interface TrainMultivariateModelDefaultHeaders {
 
 export interface TrainMultivariateModelDefaultResponse extends HttpResponse {
   status: string;
-  body: MultivariateErrorResponseOutput;
+  body: MultivariateResponseErrorOutput;
   headers: RawHttpHeaders & TrainMultivariateModelDefaultHeaders;
 }
 
@@ -123,7 +123,7 @@ export interface ListMultivariateModelsDefaultHeaders {
 
 export interface ListMultivariateModelsDefaultResponse extends HttpResponse {
   status: string;
-  body: MultivariateErrorResponseOutput;
+  body: MultivariateResponseErrorOutput;
   headers: RawHttpHeaders & ListMultivariateModelsDefaultHeaders;
 }
 
@@ -139,7 +139,7 @@ export interface DeleteMultivariateModelDefaultHeaders {
 
 export interface DeleteMultivariateModelDefaultResponse extends HttpResponse {
   status: string;
-  body: MultivariateErrorResponseOutput;
+  body: MultivariateResponseErrorOutput;
   headers: RawHttpHeaders & DeleteMultivariateModelDefaultHeaders;
 }
 
@@ -156,7 +156,7 @@ export interface GetMultivariateModelDefaultHeaders {
 
 export interface GetMultivariateModelDefaultResponse extends HttpResponse {
   status: string;
-  body: MultivariateErrorResponseOutput;
+  body: MultivariateResponseErrorOutput;
   headers: RawHttpHeaders & GetMultivariateModelDefaultHeaders;
 }
 
@@ -183,7 +183,7 @@ export interface DetectMultivariateBatchAnomalyDefaultHeaders {
 export interface DetectMultivariateBatchAnomalyDefaultResponse
   extends HttpResponse {
   status: string;
-  body: MultivariateErrorResponseOutput;
+  body: MultivariateResponseErrorOutput;
   headers: RawHttpHeaders & DetectMultivariateBatchAnomalyDefaultHeaders;
 }
 
@@ -201,6 +201,6 @@ export interface DetectMultivariateLastAnomalyDefaultHeaders {
 export interface DetectMultivariateLastAnomalyDefaultResponse
   extends HttpResponse {
   status: string;
-  body: MultivariateErrorResponseOutput;
+  body: MultivariateResponseErrorOutput;
   headers: RawHttpHeaders & DetectMultivariateLastAnomalyDefaultHeaders;
 }
diff --git a/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/src/api/operations.ts b/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/src/api/operations.ts
index c6c0deaa5e..966734a434 100644
--- a/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/src/api/operations.ts
+++ b/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/src/api/operations.ts
@@ -210,7 +210,10 @@ export function _createOrUpdateTextBlocklistSend(
       ...operationOptionsToRequestParameters(options),
       contentType:
         (options.contentType as any) ?? "application/merge-patch+json",
-      body: { description: resource["description"] },
+      body: {
+        blocklistName: resource["blocklistName"],
+        description: resource["description"],
+      },
     });
 }
 
diff --git a/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/src/models/models.ts b/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/src/models/models.ts
index 9cebdc9b56..ad9fe40123 100644
--- a/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/src/models/models.ts
+++ b/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/src/models/models.ts
@@ -4,7 +4,7 @@
 /** Text Blocklist. */
 export interface TextBlocklist {
   /** Text blocklist name. */
-  readonly blocklistName: string;
+  blocklistName: string;
   /** Text blocklist description. */
   description?: string;
 }
@@ -32,7 +32,7 @@ export interface AddOrUpdateBlockItemsResult {
 /** Item in TextBlocklist. */
 export interface TextBlockItem {
   /** Block Item Id. It will be uuid. */
-  readonly blockItemId: string;
+  blockItemId: string;
   /** Block item description. */
   description?: string;
   /** Block item content. */
diff --git a/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/src/outputModels.ts b/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/src/outputModels.ts
index f8ef8d083b..5d16f151b6 100644
--- a/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/src/outputModels.ts
+++ b/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/src/outputModels.ts
@@ -16,6 +16,9 @@ export interface UserCreatedResponseOutput {
   token: string;
 }
 
+/** The user already exists */
+export interface UserExistsResponseOutput extends ErrorModelOutput {}
+
 export interface ErrorModelOutput {
   /** A machine readable error code */
   code: string;
@@ -23,6 +26,11 @@ export interface ErrorModelOutput {
   message: string;
 }
 
+/** The user is invalid (e.g. forgot to enter email address) */
+export interface InvalidUserResponseOutput extends ErrorModelOutput {}
+
+export interface InvalidTodoItemOutput extends ErrorModelOutput {}
+
 export interface TodoPageOutput {
   /** The items in the page */
   items: Array<TodoItemOutput>;
diff --git a/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/src/responses.ts b/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/src/responses.ts
index 696ddd97bd..ab5166049a 100644
--- a/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/src/responses.ts
+++ b/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/src/responses.ts
@@ -3,9 +3,11 @@
 import { HttpResponse } from "@typespec/ts-http-runtime";
 import {
   UserCreatedResponseOutput,
-  ErrorModelOutput,
+  UserExistsResponseOutput,
+  InvalidUserResponseOutput,
   TodoPageOutput,
   TodoItemOutput,
+  InvalidTodoItemOutput,
   TodoAttachmentOutput,
 } from "./outputModels";
 
@@ -18,13 +20,13 @@ export interface UsersCreate200Response extends HttpResponse {
 /** The request conflicts with the current state of the server. */
 export interface UsersCreate409Response extends HttpResponse {
   status: "409";
-  body: ErrorModelOutput;
+  body: UserExistsResponseOutput;
 }
 
 /** Client error */
 export interface UsersCreate422Response extends HttpResponse {
   status: "422";
-  body: ErrorModelOutput;
+  body: InvalidUserResponseOutput;
 }
 
 /** The request has succeeded. */
@@ -35,7 +37,7 @@ export interface UsersValidate200Response extends HttpResponse {
 /** Client error */
 export interface UsersValidate422Response extends HttpResponse {
   status: "422";
-  body: ErrorModelOutput;
+  body: InvalidUserResponseOutput;
 }
 
 /** The request has succeeded. */
@@ -88,7 +90,7 @@ export interface TodoItemsCreateJson200Response extends HttpResponse {
 /** Client error */
 export interface TodoItemsCreateJson422Response extends HttpResponse {
   status: "422";
-  body: ErrorModelOutput;
+  body: InvalidTodoItemOutput;
 }
 
 /** The request has succeeded. */
@@ -100,7 +102,7 @@ export interface TodoItemsCreateForm200Response extends HttpResponse {
 /** Client error */
 export interface TodoItemsCreateForm422Response extends HttpResponse {
   status: "422";
-  body: ErrorModelOutput;
+  body: InvalidTodoItemOutput;
 }
 
 /** The request has succeeded. */

From a1a56099f71e694c3606ec64d23c07b5a2c8c3ef Mon Sep 17 00:00:00 2001
From: Mary Gao <yanmeigao1210@gmail.com>
Date: Wed, 6 Mar 2024 15:35:40 +0800
Subject: [PATCH 5/6] Regenerate API view

---
 .../review/ai-anomaly-detector.api.md         | 20 +++++++++++------
 .../review/ai-content-safety.api.md           |  4 ++--
 .../review/todo-non-branded.api.md            | 22 ++++++++++++++-----
 3 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/review/ai-anomaly-detector.api.md b/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/review/ai-anomaly-detector.api.md
index cae2846141..8325ace9c1 100644
--- a/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/review/ai-anomaly-detector.api.md
+++ b/packages/typespec-test/test/anomalyDetector/generated/typespec-ts/review/ai-anomaly-detector.api.md
@@ -49,7 +49,7 @@ export interface DeleteMultivariateModelDefaultHeaders {
 // @public (undocumented)
 export interface DeleteMultivariateModelDefaultResponse extends HttpResponse {
     // (undocumented)
-    body: MultivariateErrorResponseOutput;
+    body: MultivariateResponseErrorOutput;
     // (undocumented)
     headers: RawHttpHeaders & DeleteMultivariateModelDefaultHeaders;
     // (undocumented)
@@ -93,7 +93,7 @@ export interface DetectMultivariateBatchAnomalyDefaultHeaders {
 // @public (undocumented)
 export interface DetectMultivariateBatchAnomalyDefaultResponse extends HttpResponse {
     // (undocumented)
-    body: MultivariateErrorResponseOutput;
+    body: MultivariateResponseErrorOutput;
     // (undocumented)
     headers: RawHttpHeaders & DetectMultivariateBatchAnomalyDefaultHeaders;
     // (undocumented)
@@ -129,7 +129,7 @@ export interface DetectMultivariateLastAnomalyDefaultHeaders {
 // @public (undocumented)
 export interface DetectMultivariateLastAnomalyDefaultResponse extends HttpResponse {
     // (undocumented)
-    body: MultivariateErrorResponseOutput;
+    body: MultivariateResponseErrorOutput;
     // (undocumented)
     headers: RawHttpHeaders & DetectMultivariateLastAnomalyDefaultHeaders;
     // (undocumented)
@@ -271,7 +271,7 @@ export interface GetMultivariateBatchDetectionResultDefaultHeaders {
 // @public (undocumented)
 export interface GetMultivariateBatchDetectionResultDefaultResponse extends HttpResponse {
     // (undocumented)
-    body: MultivariateErrorResponseOutput;
+    body: MultivariateResponseErrorOutput;
     // (undocumented)
     headers: RawHttpHeaders & GetMultivariateBatchDetectionResultDefaultHeaders;
     // (undocumented)
@@ -297,7 +297,7 @@ export interface GetMultivariateModelDefaultHeaders {
 // @public (undocumented)
 export interface GetMultivariateModelDefaultResponse extends HttpResponse {
     // (undocumented)
-    body: MultivariateErrorResponseOutput;
+    body: MultivariateResponseErrorOutput;
     // (undocumented)
     headers: RawHttpHeaders & GetMultivariateModelDefaultHeaders;
     // (undocumented)
@@ -359,7 +359,7 @@ export interface ListMultivariateModelsDefaultHeaders {
 // @public (undocumented)
 export interface ListMultivariateModelsDefaultResponse extends HttpResponse {
     // (undocumented)
-    body: MultivariateErrorResponseOutput;
+    body: MultivariateResponseErrorOutput;
     // (undocumented)
     headers: RawHttpHeaders & ListMultivariateModelsDefaultHeaders;
     // (undocumented)
@@ -548,6 +548,12 @@ export interface MultivariateMultivariateLastDetectionResultOutput {
     variableStates?: Array<MultivariateVariableStateOutput>;
 }
 
+// @public
+export interface MultivariateResponseErrorOutput {
+    code: string;
+    message: string;
+}
+
 // @public
 export interface MultivariateVariableState {
     effectiveCount?: number;
@@ -638,7 +644,7 @@ export interface TrainMultivariateModelDefaultHeaders {
 // @public (undocumented)
 export interface TrainMultivariateModelDefaultResponse extends HttpResponse {
     // (undocumented)
-    body: MultivariateErrorResponseOutput;
+    body: MultivariateResponseErrorOutput;
     // (undocumented)
     headers: RawHttpHeaders & TrainMultivariateModelDefaultHeaders;
     // (undocumented)
diff --git a/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/review/ai-content-safety.api.md b/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/review/ai-content-safety.api.md
index 77e23bdc58..4a7910cc14 100644
--- a/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/review/ai-content-safety.api.md
+++ b/packages/typespec-test/test/contentsafety_modular/generated/typespec-ts/review/ai-content-safety.api.md
@@ -175,7 +175,7 @@ export interface TextAnalyzeSeverityResult {
 
 // @public
 export interface TextBlockItem {
-    readonly blockItemId: string;
+    blockItemId: string;
     description?: string;
     text: string;
 }
@@ -188,7 +188,7 @@ export interface TextBlockItemInfo {
 
 // @public
 export interface TextBlocklist {
-    readonly blocklistName: string;
+    blocklistName: string;
     description?: string;
 }
 
diff --git a/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/review/todo-non-branded.api.md b/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/review/todo-non-branded.api.md
index c4b50522a3..595ccbbd4a 100644
--- a/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/review/todo-non-branded.api.md
+++ b/packages/typespec-test/test/todo_non_branded/generated/typespec-ts/review/todo-non-branded.api.md
@@ -35,6 +35,14 @@ export interface ErrorModelOutput {
     message: string;
 }
 
+// @public (undocumented)
+export interface InvalidTodoItemOutput extends ErrorModelOutput {
+}
+
+// @public
+export interface InvalidUserResponseOutput extends ErrorModelOutput {
+}
+
 // @public (undocumented)
 export interface Routes {
     (path: "/users"): UsersCreate;
@@ -194,7 +202,7 @@ export interface TodoItemsCreateForm200Response extends HttpResponse {
 // @public
 export interface TodoItemsCreateForm422Response extends HttpResponse {
     // (undocumented)
-    body: ErrorModelOutput;
+    body: InvalidTodoItemOutput;
     // (undocumented)
     status: "422";
 }
@@ -228,7 +236,7 @@ export interface TodoItemsCreateJson200Response extends HttpResponse {
 // @public
 export interface TodoItemsCreateJson422Response extends HttpResponse {
     // (undocumented)
-    body: ErrorModelOutput;
+    body: InvalidTodoItemOutput;
     // (undocumented)
     status: "422";
 }
@@ -413,6 +421,10 @@ export interface UserCreatedResponseOutput {
     username: string;
 }
 
+// @public
+export interface UserExistsResponseOutput extends ErrorModelOutput {
+}
+
 // @public (undocumented)
 export interface UsersCreate {
     // (undocumented)
@@ -430,7 +442,7 @@ export interface UsersCreate200Response extends HttpResponse {
 // @public
 export interface UsersCreate409Response extends HttpResponse {
     // (undocumented)
-    body: ErrorModelOutput;
+    body: UserExistsResponseOutput;
     // (undocumented)
     status: "409";
 }
@@ -438,7 +450,7 @@ export interface UsersCreate409Response extends HttpResponse {
 // @public
 export interface UsersCreate422Response extends HttpResponse {
     // (undocumented)
-    body: ErrorModelOutput;
+    body: InvalidUserResponseOutput;
     // (undocumented)
     status: "422";
 }
@@ -575,7 +587,7 @@ export interface UsersValidate200Response extends HttpResponse {
 // @public
 export interface UsersValidate422Response extends HttpResponse {
     // (undocumented)
-    body: ErrorModelOutput;
+    body: InvalidUserResponseOutput;
     // (undocumented)
     status: "422";
 }

From 64c05f27f0c19c5435dad7191ef60ec2a6f1a324 Mon Sep 17 00:00:00 2001
From: Mary Gao <yanmeigao1210@gmail.com>
Date: Thu, 7 Mar 2024 22:12:41 +0800
Subject: [PATCH 6/6] Update the UTs

---
 .../test/modularUnit/modelsGenerator.spec.ts  | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/packages/typespec-ts/test/modularUnit/modelsGenerator.spec.ts b/packages/typespec-ts/test/modularUnit/modelsGenerator.spec.ts
index d67b07bf74..4a4e5d2ba6 100644
--- a/packages/typespec-ts/test/modularUnit/modelsGenerator.spec.ts
+++ b/packages/typespec-ts/test/modularUnit/modelsGenerator.spec.ts
@@ -1978,6 +1978,33 @@ describe("`is`", () => {
   });
 });
 
+describe("`extends`", () => {
+  it("should generate correct name and properties if A extends B", async () => {
+    const modelFile = await emitModularModelsFromTypeSpec(`
+      model B {
+        prop1: string;
+        prop2: string;
+      }
+      model A extends B {
+        @query
+        name: string;
+      };
+      op read(@body body: A): void;
+      `);
+    assert.ok(modelFile);
+    await assertEqualContent(
+      modelFile!.getFullText()!,
+      `
+      export interface B {
+        prop1: string;
+        prop2: string;
+      }
+      
+      export interface A extends B {}`
+    );
+  });
+});
+
 describe("visibility", () => {
   it("should generate readonly for @visibility('read')", async () => {
     const modelFile = await emitModularModelsFromTypeSpec(`