diff --git a/baselines/audioworklet.generated.d.ts b/baselines/audioworklet.generated.d.ts
index 9440da16e..be0c723c6 100644
--- a/baselines/audioworklet.generated.d.ts
+++ b/baselines/audioworklet.generated.d.ts
@@ -1031,7 +1031,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 4529183fb..b2840f238 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -30349,7 +30349,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/serviceworker.generated.d.ts b/baselines/serviceworker.generated.d.ts
index 254fe2c9e..01aaca4c2 100644
--- a/baselines/serviceworker.generated.d.ts
+++ b/baselines/serviceworker.generated.d.ts
@@ -8153,7 +8153,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/sharedworker.generated.d.ts b/baselines/sharedworker.generated.d.ts
index a8f1738d4..69dd5b56a 100644
--- a/baselines/sharedworker.generated.d.ts
+++ b/baselines/sharedworker.generated.d.ts
@@ -7736,7 +7736,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.5/audioworklet.generated.d.ts b/baselines/ts5.5/audioworklet.generated.d.ts
index 8d066e376..dbe38b1ad 100644
--- a/baselines/ts5.5/audioworklet.generated.d.ts
+++ b/baselines/ts5.5/audioworklet.generated.d.ts
@@ -1028,7 +1028,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.5/dom.generated.d.ts b/baselines/ts5.5/dom.generated.d.ts
index 09cc2120f..80857f7bc 100644
--- a/baselines/ts5.5/dom.generated.d.ts
+++ b/baselines/ts5.5/dom.generated.d.ts
@@ -30325,7 +30325,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.5/serviceworker.generated.d.ts b/baselines/ts5.5/serviceworker.generated.d.ts
index c152f464f..6fdfe4182 100644
--- a/baselines/ts5.5/serviceworker.generated.d.ts
+++ b/baselines/ts5.5/serviceworker.generated.d.ts
@@ -8150,7 +8150,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.5/sharedworker.generated.d.ts b/baselines/ts5.5/sharedworker.generated.d.ts
index b4a61a7d7..42e06d36d 100644
--- a/baselines/ts5.5/sharedworker.generated.d.ts
+++ b/baselines/ts5.5/sharedworker.generated.d.ts
@@ -7733,7 +7733,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.5/webworker.generated.d.ts b/baselines/ts5.5/webworker.generated.d.ts
index 51a1b7bf4..5dadf14da 100644
--- a/baselines/ts5.5/webworker.generated.d.ts
+++ b/baselines/ts5.5/webworker.generated.d.ts
@@ -9273,7 +9273,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.6/audioworklet.generated.d.ts b/baselines/ts5.6/audioworklet.generated.d.ts
index 8d066e376..dbe38b1ad 100644
--- a/baselines/ts5.6/audioworklet.generated.d.ts
+++ b/baselines/ts5.6/audioworklet.generated.d.ts
@@ -1028,7 +1028,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.6/dom.generated.d.ts b/baselines/ts5.6/dom.generated.d.ts
index 525f6cab8..937e7b336 100644
--- a/baselines/ts5.6/dom.generated.d.ts
+++ b/baselines/ts5.6/dom.generated.d.ts
@@ -30346,7 +30346,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.6/serviceworker.generated.d.ts b/baselines/ts5.6/serviceworker.generated.d.ts
index c152f464f..6fdfe4182 100644
--- a/baselines/ts5.6/serviceworker.generated.d.ts
+++ b/baselines/ts5.6/serviceworker.generated.d.ts
@@ -8150,7 +8150,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.6/sharedworker.generated.d.ts b/baselines/ts5.6/sharedworker.generated.d.ts
index b4a61a7d7..42e06d36d 100644
--- a/baselines/ts5.6/sharedworker.generated.d.ts
+++ b/baselines/ts5.6/sharedworker.generated.d.ts
@@ -7733,7 +7733,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.6/webworker.generated.d.ts b/baselines/ts5.6/webworker.generated.d.ts
index 51a1b7bf4..5dadf14da 100644
--- a/baselines/ts5.6/webworker.generated.d.ts
+++ b/baselines/ts5.6/webworker.generated.d.ts
@@ -9273,7 +9273,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.9/audioworklet.generated.d.ts b/baselines/ts5.9/audioworklet.generated.d.ts
index 141647398..af701138c 100644
--- a/baselines/ts5.9/audioworklet.generated.d.ts
+++ b/baselines/ts5.9/audioworklet.generated.d.ts
@@ -1028,7 +1028,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.9/dom.generated.d.ts b/baselines/ts5.9/dom.generated.d.ts
index 3d77d3cc6..a52c84ba7 100644
--- a/baselines/ts5.9/dom.generated.d.ts
+++ b/baselines/ts5.9/dom.generated.d.ts
@@ -30346,7 +30346,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.9/serviceworker.generated.d.ts b/baselines/ts5.9/serviceworker.generated.d.ts
index 91c2d0e00..2b9254350 100644
--- a/baselines/ts5.9/serviceworker.generated.d.ts
+++ b/baselines/ts5.9/serviceworker.generated.d.ts
@@ -8150,7 +8150,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.9/sharedworker.generated.d.ts b/baselines/ts5.9/sharedworker.generated.d.ts
index 5f0075fe2..99f89b7c9 100644
--- a/baselines/ts5.9/sharedworker.generated.d.ts
+++ b/baselines/ts5.9/sharedworker.generated.d.ts
@@ -7733,7 +7733,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/ts5.9/webworker.generated.d.ts b/baselines/ts5.9/webworker.generated.d.ts
index a56e00793..c436320ae 100644
--- a/baselines/ts5.9/webworker.generated.d.ts
+++ b/baselines/ts5.9/webworker.generated.d.ts
@@ -9273,7 +9273,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/baselines/webworker.generated.d.ts b/baselines/webworker.generated.d.ts
index ae16e24eb..e1de8865b 100644
--- a/baselines/webworker.generated.d.ts
+++ b/baselines/webworker.generated.d.ts
@@ -9276,7 +9276,7 @@ interface ReadableStreamDefaultController<R = any> {
      *
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/ReadableStreamDefaultController/enqueue)
      */
-    enqueue(chunk?: R): void;
+    enqueue(chunk: R): void;
     /**
      * The **`error()`** method of the ReadableStreamDefaultController interface causes any future interactions with the associated stream to error.
      *
diff --git a/inputfiles/overridingTypes.jsonc b/inputfiles/overridingTypes.jsonc
index 629abafdc..0221c4895 100644
--- a/inputfiles/overridingTypes.jsonc
+++ b/inputfiles/overridingTypes.jsonc
@@ -2249,6 +2249,7 @@
                                     "param": [
                                         {
                                             "name": "chunk",
+                                            "optional": false,
                                             "overrideType": "R"
                                         }
                                     ]