diff --git a/packages/flutter/lib/fix_data.yaml b/packages/flutter/lib/fix_data.yaml
index b676546716..ab2c1a8333 100644
--- a/packages/flutter/lib/fix_data.yaml
+++ b/packages/flutter/lib/fix_data.yaml
@@ -11,6 +11,52 @@
 version: 1
 transforms:
 
+  # Changes made in https://github.com/flutter/flutter/pull/66305
+  - title: 'Migrate to clipBehavior'
+    date: 2020-09-22
+    element:
+      uris: [ 'widgets.dart' ]
+      field: 'overflow'
+      inClass: 'Stack'
+    changes:
+      - kind: 'rename'
+        newName: 'clipBehavior'
+
+  # Changes made in https://github.com/flutter/flutter/pull/66305
+  - title: 'Migrate to clipBehavior'
+    date: 2020-09-22
+    element:
+      uris: [ 'widgets.dart' ]
+      constructor: ''
+      inClass: 'Stack'
+    oneOf:
+      - if: "overflow == 'Overflow.clip'"
+        changes:
+          - kind: 'addParameter'
+            index: 0
+            name: 'clipBehavior'
+            style: optional_named
+            argumentValue:
+              expression: 'Clip.hardEdge'
+              requiredIf: "overflow == 'Overflow.clip'"
+          - kind: 'removeParameter'
+            name: 'overflow'
+      - if: "overflow == 'Overflow.visible'"
+        changes:
+          - kind: 'addParameter'
+            index: 0
+            name: 'clipBehavior'
+            style: optional_named
+            argumentValue:
+              expression: 'Clip.none'
+              requiredIf: "overflow == 'Overflow.visible'"
+          - kind: 'removeParameter'
+            name: 'overflow'
+    variables:
+      overflow:
+        kind: 'fragment'
+        value: 'arguments[overflow]'
+
   # Change made in https://github.com/flutter/flutter/pull/44189.
   - title: 'Rename to dependOnInheritedElement'
     date: 2019-11-22
diff --git a/packages/flutter/test_fixes/widgets.dart b/packages/flutter/test_fixes/widgets.dart
index d2885520c1..3d6db09274 100644
--- a/packages/flutter/test_fixes/widgets.dart
+++ b/packages/flutter/test_fixes/widgets.dart
@@ -23,4 +23,9 @@ void main() {
   buildContext.ancestorStateOfType(TypeMatcher<targetType>());
   buildContext.rootAncestorStateOfType(TypeMatcher<targetType>());
   buildContext.ancestorRenderObjectOfType(TypeMatcher<targetType>());
+
+  // Changes made in https://github.com/flutter/flutter/pull/66305
+  const Stack stack = Stack(overflow: Overflow.visible);
+  const Stack stack = Stack(overflow: Overflow.clip);
+  final behavior = stack.overflow;
 }
diff --git a/packages/flutter/test_fixes/widgets.dart.expect b/packages/flutter/test_fixes/widgets.dart.expect
index e985bd47f5..0fffa0a133 100644
--- a/packages/flutter/test_fixes/widgets.dart.expect
+++ b/packages/flutter/test_fixes/widgets.dart.expect
@@ -23,4 +23,9 @@ void main() {
   buildContext.findAncestorStateOfType<targetType>();
   buildContext.findRootAncestorStateOfType<targetType>();
   buildContext.findAncestorRenderObjectOfType<targetType>();
+
+  // Changes made in https://github.com/flutter/flutter/pull/66305
+  const Stack stack = Stack(clipBehavior: Clip.none);
+  const Stack stack = Stack(clipBehavior: Clip.hardEdge);
+  final behavior = stack.clipBehavior;
 }