diff --git a/packages/internal-test-utils/__tests__/ReactInternalTestUtils-test.js b/packages/internal-test-utils/__tests__/ReactInternalTestUtils-test.js
index e561c9b3dbbe2..0b9cc1f252f79 100644
--- a/packages/internal-test-utils/__tests__/ReactInternalTestUtils-test.js
+++ b/packages/internal-test-utils/__tests__/ReactInternalTestUtils-test.js
@@ -152,7 +152,7 @@ describe('ReactInternalTestUtils', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'B', 'C']);
diff --git a/packages/react-client/src/__tests__/ReactFlight-test.js b/packages/react-client/src/__tests__/ReactFlight-test.js
index 50608dcca5e3e..0e507876d965b 100644
--- a/packages/react-client/src/__tests__/ReactFlight-test.js
+++ b/packages/react-client/src/__tests__/ReactFlight-test.js
@@ -475,7 +475,7 @@ describe('ReactFlight', () => {
       return use(promise);
     }
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         ReactNoop.render(
           <>
@@ -554,7 +554,7 @@ describe('ReactFlight', () => {
       return use(promise);
     }
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         ReactNoop.render(
           <NoErrorExpected>
diff --git a/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js b/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
index 118a961767ec3..2c7597a6551dd 100644
--- a/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
+++ b/packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js
@@ -61,7 +61,7 @@ describe('ReactHooksInspectionIntegration', () => {
     const {onMouseDown: setStateA, onMouseUp: setStateB} =
       renderer.root.findByType('div').props;
 
-    await act(async () => setStateA('Hi'));
+    await act(() => setStateA('Hi'));
 
     childFiber = renderer.root.findByType(Foo)._currentFiber();
     tree = ReactDebugTools.inspectHooksOfFiber(childFiber);
@@ -83,7 +83,7 @@ describe('ReactHooksInspectionIntegration', () => {
       },
     ]);
 
-    await act(async () => setStateB('world!'));
+    await act(() => setStateB('world!'));
 
     childFiber = renderer.root.findByType(Foo)._currentFiber();
     tree = ReactDebugTools.inspectHooksOfFiber(childFiber);
@@ -141,7 +141,7 @@ describe('ReactHooksInspectionIntegration', () => {
       );
     }
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<Foo prop="prop" />);
     });
 
@@ -203,7 +203,7 @@ describe('ReactHooksInspectionIntegration', () => {
       },
     ]);
 
-    await act(async () => {
+    await act(() => {
       updateStates();
     });
 
@@ -301,7 +301,7 @@ describe('ReactHooksInspectionIntegration', () => {
       );
     }
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<Foo prop="prop" />);
     });
 
@@ -370,7 +370,7 @@ describe('ReactHooksInspectionIntegration', () => {
       },
     ]);
 
-    await act(async () => {
+    await act(() => {
       updateStates();
     });
 
@@ -984,7 +984,7 @@ describe('ReactHooksInspectionIntegration', () => {
       children: ['count: ', '1'],
     });
 
-    await act(async () => incrementCount());
+    await act(() => incrementCount());
     expect(renderer.toJSON()).toEqual({
       type: 'div',
       props: {},
diff --git a/packages/react-dom/src/__tests__/ReactDOMConsoleErrorReporting-test.js b/packages/react-dom/src/__tests__/ReactDOMConsoleErrorReporting-test.js
index d4cc22e44668a..9ce6d9676141a 100644
--- a/packages/react-dom/src/__tests__/ReactDOMConsoleErrorReporting-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMConsoleErrorReporting-test.js
@@ -72,11 +72,11 @@ describe('ReactDOMConsoleErrorReporting', () => {
       }
 
       const root = ReactDOMClient.createRoot(container);
-      await act(async () => {
+      await act(() => {
         root.render(<Foo />);
       });
 
-      await act(async () => {
+      await act(() => {
         container.firstChild.dispatchEvent(
           new MouseEvent('click', {
             bubbles: true,
@@ -146,7 +146,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         root.render(<NoError />);
       });
       expect(container.textContent).toBe('OK');
@@ -229,7 +229,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         root.render(<NoError />);
       });
       expect(container.textContent).toBe('OK');
@@ -247,7 +247,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       }
 
       const root = ReactDOMClient.createRoot(container);
-      await act(async () => {
+      await act(() => {
         root.render(
           <ErrorBoundary>
             <Foo />
@@ -315,7 +315,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         root.render(<NoError />);
       });
       expect(container.textContent).toBe('OK');
@@ -384,7 +384,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         root.render(<NoError />);
       });
       expect(container.textContent).toBe('OK');
@@ -405,7 +405,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       }
 
       const root = ReactDOMClient.createRoot(container);
-      await act(async () => {
+      await act(() => {
         root.render(
           <ErrorBoundary>
             <Foo />
@@ -456,7 +456,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         root.render(<NoError />);
       });
       expect(container.textContent).toBe('OK');
@@ -525,7 +525,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         root.render(<NoError />);
       });
       expect(container.textContent).toBe('OK');
@@ -546,7 +546,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       }
 
       const root = ReactDOMClient.createRoot(container);
-      await act(async () => {
+      await act(() => {
         root.render(
           <ErrorBoundary>
             <Foo />
@@ -597,7 +597,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         root.render(<NoError />);
       });
       expect(container.textContent).toBe('OK');
@@ -623,11 +623,11 @@ describe('ReactDOMConsoleErrorReporting', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<Foo />, container);
       });
 
-      await act(async () => {
+      await act(() => {
         container.firstChild.dispatchEvent(
           new MouseEvent('click', {
             bubbles: true,
@@ -698,7 +698,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<NoError />, container);
       });
       expect(container.textContent).toBe('OK');
@@ -765,7 +765,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<NoError />, container);
       });
       expect(container.textContent).toBe('OK');
@@ -784,7 +784,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
         throw Error('Boom');
       }
 
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(
           <ErrorBoundary>
             <Foo />
@@ -837,7 +837,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<NoError />, container);
       });
       expect(container.textContent).toBe('OK');
@@ -907,7 +907,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<NoError />, container);
       });
       expect(container.textContent).toBe('OK');
@@ -929,7 +929,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
         return null;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(
           <ErrorBoundary>
             <Foo />
@@ -982,7 +982,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<NoError />, container);
       });
       expect(container.textContent).toBe('OK');
@@ -1053,7 +1053,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<NoError />, container);
       });
       expect(container.textContent).toBe('OK');
@@ -1075,7 +1075,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
         return null;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(
           <ErrorBoundary>
             <Foo />
@@ -1128,7 +1128,7 @@ describe('ReactDOMConsoleErrorReporting', () => {
       // Check next render doesn't throw.
       windowOnError.mockReset();
       console.error.mockReset();
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<NoError />, container);
       });
       expect(container.textContent).toBe('OK');
diff --git a/packages/react-dom/src/__tests__/ReactDOMFiberAsync-test.js b/packages/react-dom/src/__tests__/ReactDOMFiberAsync-test.js
index f0e984de05d7d..79d70b4bf2437 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFiberAsync-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFiberAsync-test.js
@@ -423,7 +423,7 @@ describe('ReactDOMFiberAsync', () => {
       }
 
       const root = ReactDOMClient.createRoot(container);
-      await act(async () => {
+      await act(() => {
         root.render(<Form />);
       });
 
@@ -474,7 +474,7 @@ describe('ReactDOMFiberAsync', () => {
       }
 
       const root = ReactDOMClient.createRoot(container);
-      await act(async () => {
+      await act(() => {
         root.render(<Form />);
       });
 
@@ -484,7 +484,7 @@ describe('ReactDOMFiberAsync', () => {
       // Dispatch a click event on the Disable-button.
       const firstEvent = document.createEvent('Event');
       firstEvent.initEvent('click', true, true);
-      await act(async () => {
+      await act(() => {
         disableButton.dispatchEvent(firstEvent);
       });
 
@@ -498,7 +498,7 @@ describe('ReactDOMFiberAsync', () => {
       const secondEvent = document.createEvent('Event');
       secondEvent.initEvent('click', true, true);
       // This should force the pending update to flush which disables the submit button before the event is invoked.
-      await act(async () => {
+      await act(() => {
         submitButton.dispatchEvent(secondEvent);
       });
 
@@ -533,7 +533,7 @@ describe('ReactDOMFiberAsync', () => {
       }
 
       const root = ReactDOMClient.createRoot(container);
-      await act(async () => {
+      await act(() => {
         root.render(<Form />);
       });
 
@@ -543,7 +543,7 @@ describe('ReactDOMFiberAsync', () => {
       // Dispatch a click event on the Enable-button.
       const firstEvent = document.createEvent('Event');
       firstEvent.initEvent('click', true, true);
-      await act(async () => {
+      await act(() => {
         enableButton.dispatchEvent(firstEvent);
       });
 
@@ -557,7 +557,7 @@ describe('ReactDOMFiberAsync', () => {
       const secondEvent = document.createEvent('Event');
       secondEvent.initEvent('click', true, true);
       // This should force the pending update to flush which enables the submit button before the event is invoked.
-      await act(async () => {
+      await act(() => {
         submitButton.dispatchEvent(secondEvent);
       });
 
@@ -643,7 +643,7 @@ describe('ReactDOMFiberAsync', () => {
     }
 
     const oldRoot = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       oldRoot.render(<OldApp />);
     });
 
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
index b95595a4c4cc4..766cdc66a3459 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
@@ -349,7 +349,7 @@ describe('ReactDOMFizzServer', () => {
     };
 
     try {
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(
           <div>
             <div>
@@ -373,7 +373,7 @@ describe('ReactDOMFizzServer', () => {
           <div>Loading...</div>
         </div>,
       );
-      await act(async () => {
+      await act(() => {
         resolveA({default: Text});
       });
       expect(getVisibleChildren(container)).toEqual(
@@ -382,7 +382,7 @@ describe('ReactDOMFizzServer', () => {
           <div>Loading...</div>
         </div>,
       );
-      await act(async () => {
+      await act(() => {
         resolveB({default: TextWithPunctuation});
       });
       expect(getVisibleChildren(container)).toEqual(
@@ -432,7 +432,7 @@ describe('ReactDOMFizzServer', () => {
 
     // Server-side
     const [App, resolve] = makeApp();
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />);
       pipe(writable);
     });
@@ -441,7 +441,7 @@ describe('ReactDOMFizzServer', () => {
         <span>Loading...</span>
       </div>,
     );
-    await act(async () => {
+    await act(() => {
       resolve();
     });
     expect(getVisibleChildren(container)).toEqual(
@@ -453,7 +453,7 @@ describe('ReactDOMFizzServer', () => {
 
     // Client-side
     const [HydrateApp, hydrateResolve] = makeApp();
-    await act(async () => {
+    await act(() => {
       ReactDOMClient.hydrateRoot(container, <HydrateApp />);
     });
 
@@ -464,7 +464,7 @@ describe('ReactDOMFizzServer', () => {
       </div>,
     );
 
-    await act(async () => {
+    await act(() => {
       hydrateResolve();
     });
     expect(getVisibleChildren(container)).toEqual(
@@ -485,7 +485,7 @@ describe('ReactDOMFizzServer', () => {
         });
       });
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(
           <div>
             <Suspense fallback={<Text text="Loading..." />}>
@@ -497,7 +497,7 @@ describe('ReactDOMFizzServer', () => {
         pipe(writable);
       });
       expect(getVisibleChildren(container)).toEqual(<div>Loading...</div>);
-      await act(async () => {
+      await act(() => {
         resolve({default: Text});
       });
       expect(getVisibleChildren(container)).toEqual(<div>Hello</div>);
@@ -545,7 +545,7 @@ describe('ReactDOMFizzServer', () => {
     const expectedDigest = onError(theError);
     loggedErrors.length = 0;
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App isClient={false} />, {
         bootstrapScriptContent: '__INIT__();',
         onError,
@@ -562,7 +562,7 @@ describe('ReactDOMFizzServer', () => {
 
     expect(loggedErrors).toEqual([]);
 
-    await act(async () => {
+    await act(() => {
       rejectComponent(theError);
     });
 
@@ -604,7 +604,7 @@ describe('ReactDOMFizzServer', () => {
       });
     });
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <div>
           <Suspense fallback={<Text text="Loading..." />}>
@@ -624,7 +624,7 @@ describe('ReactDOMFizzServer', () => {
         renderOptions.unstable_externalRuntimeSrc,
       ).length,
     ).toBe(1);
-    await act(async () => {
+    await act(() => {
       resolveElement({default: <Text text="Hello" />});
     });
     expect(getVisibleChildren(container)).toEqual(<div>Hello</div>);
@@ -658,7 +658,7 @@ describe('ReactDOMFizzServer', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <App isClient={false} />,
 
@@ -684,7 +684,7 @@ describe('ReactDOMFizzServer', () => {
 
     expect(loggedErrors).toEqual([]);
 
-    await act(async () => {
+    await act(() => {
       rejectElement(theError);
     });
 
@@ -754,7 +754,7 @@ describe('ReactDOMFizzServer', () => {
     const expectedDigest = onError(theError);
     loggedErrors.length = 0;
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <App />,
 
@@ -822,7 +822,7 @@ describe('ReactDOMFizzServer', () => {
     const expectedDigest = onError(theError);
     loggedErrors.length = 0;
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <App />,
 
@@ -845,7 +845,7 @@ describe('ReactDOMFizzServer', () => {
 
     expect(getVisibleChildren(container)).toEqual(<div>Loading...</div>);
 
-    await act(async () => {
+    await act(() => {
       rejectComponent(theError);
     });
 
@@ -878,7 +878,7 @@ describe('ReactDOMFizzServer', () => {
   });
 
   it('should asynchronously load the suspense boundary', async () => {
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <div>
           <Suspense fallback={<Text text="Loading..." />}>
@@ -889,7 +889,7 @@ describe('ReactDOMFizzServer', () => {
       pipe(writable);
     });
     expect(getVisibleChildren(container)).toEqual(<div>Loading...</div>);
-    await act(async () => {
+    await act(() => {
       resolveText('Hello World');
     });
     expect(getVisibleChildren(container)).toEqual(<div>Hello World</div>);
@@ -917,7 +917,7 @@ describe('ReactDOMFizzServer', () => {
       ReactDOMClient.hydrateRoot(container, <App />);
     };
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />, {
         bootstrapScriptContent: '__INIT__();',
       });
@@ -937,7 +937,7 @@ describe('ReactDOMFizzServer', () => {
     expect(getVisibleChildren(container)).toEqual(<div>Loading...</div>);
 
     // The server now updates the content in place in the fallback.
-    await act(async () => {
+    await act(() => {
       resolveText('Hello');
     });
 
@@ -991,7 +991,7 @@ describe('ReactDOMFizzServer', () => {
     const loggedErrors = [];
 
     // We originally suspend the boundary and start streaming the loading state.
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <App />,
 
@@ -1017,7 +1017,7 @@ describe('ReactDOMFizzServer', () => {
     expect(getVisibleChildren(container)).toEqual(<div>Loading...</div>);
 
     const theError = new Error('Error Message');
-    await act(async () => {
+    await act(() => {
       rejectText('This Errors', theError);
     });
 
@@ -1073,7 +1073,7 @@ describe('ReactDOMFizzServer', () => {
     }
 
     // We originally suspend the boundary and start streaming the loading state.
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App showMore={false} />);
       pipe(writable);
     });
@@ -1146,7 +1146,7 @@ describe('ReactDOMFizzServer', () => {
     }
 
     let controls;
-    await act(async () => {
+    await act(() => {
       controls = renderToPipeableStream(<App />, {onError});
       controls.pipe(writable);
     });
@@ -1166,7 +1166,7 @@ describe('ReactDOMFizzServer', () => {
     expect(getVisibleChildren(container)).toEqual(<div>Loading...</div>);
 
     // We abort the server response.
-    await act(async () => {
+    await act(() => {
       controls.abort();
     });
 
@@ -1216,7 +1216,7 @@ describe('ReactDOMFizzServer', () => {
       writable.write(chunk, encoding, next);
     };
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         // We use two nested boundaries to flush out coverage of an old reentrancy bug.
         <Suspense fallback="Loading...">
@@ -1240,7 +1240,7 @@ describe('ReactDOMFizzServer', () => {
       );
     });
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <Suspense fallback={<Text text="Loading B..." />}>
           <Text text="This will show B: " />
@@ -1264,7 +1264,7 @@ describe('ReactDOMFizzServer', () => {
       <div id="container-B">Loading B...</div>,
     ]);
 
-    await act(async () => {
+    await act(() => {
       resolveText('B');
     });
 
@@ -1275,7 +1275,7 @@ describe('ReactDOMFizzServer', () => {
       </div>,
     ]);
 
-    await act(async () => {
+    await act(() => {
       resolveText('A');
     });
 
@@ -1336,7 +1336,7 @@ describe('ReactDOMFizzServer', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />);
       pipe(writable);
     });
@@ -1347,15 +1347,15 @@ describe('ReactDOMFizzServer', () => {
       </div>,
     );
 
-    await act(async () => {
+    await act(() => {
       resolveText('Hello');
     });
 
-    await act(async () => {
+    await act(() => {
       resolveText('World');
     });
 
-    await act(async () => {
+    await act(() => {
       resolveText('my-path');
       resolveText('my-mi');
     });
@@ -1423,7 +1423,7 @@ describe('ReactDOMFizzServer', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />);
       pipe(writable);
     });
@@ -1438,15 +1438,15 @@ describe('ReactDOMFizzServer', () => {
       </table>,
     );
 
-    await act(async () => {
+    await act(() => {
       resolveText('A');
     });
 
-    await act(async () => {
+    await act(() => {
       resolveText('B');
     });
 
-    await act(async () => {
+    await act(() => {
       resolveText('C');
     });
 
@@ -1476,7 +1476,7 @@ describe('ReactDOMFizzServer', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <App />,
 
@@ -1499,7 +1499,7 @@ describe('ReactDOMFizzServer', () => {
       </svg>,
     );
 
-    await act(async () => {
+    await act(() => {
       resolveText('my-path');
     });
 
@@ -1562,7 +1562,7 @@ describe('ReactDOMFizzServer', () => {
     };
 
     try {
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<A />);
         pipe(writable);
       });
@@ -1589,7 +1589,7 @@ describe('ReactDOMFizzServer', () => {
         expect(mockError).not.toHaveBeenCalled();
       }
 
-      await act(async () => {
+      await act(() => {
         resolveText('Hello');
         resolveText('World');
       });
@@ -1660,7 +1660,7 @@ describe('ReactDOMFizzServer', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <TestProvider ctx="A">
           <div>
@@ -1680,7 +1680,7 @@ describe('ReactDOMFizzServer', () => {
         Loading: <b>A</b>
       </div>,
     );
-    await act(async () => {
+    await act(() => {
       resolveText('Hello: ');
     });
     expect(getVisibleChildren(container)).toEqual(
@@ -1717,7 +1717,7 @@ describe('ReactDOMFizzServer', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <div>
           <PrintA />
@@ -1741,7 +1741,7 @@ describe('ReactDOMFizzServer', () => {
         A0<div>Loading...</div>A0
       </div>,
     );
-    await act(async () => {
+    await act(() => {
       resolveText('Child:');
     });
     expect(getVisibleChildren(container)).toEqual(
@@ -1778,7 +1778,7 @@ describe('ReactDOMFizzServer', () => {
     }
 
     const loggedErrors = [];
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <div>
           <PrintA />
@@ -1846,7 +1846,7 @@ describe('ReactDOMFizzServer', () => {
     loggedErrors.length = 0;
 
     let controls;
-    await act(async () => {
+    await act(() => {
       controls = renderToPipeableStream(
         <App isClient={false} />,
 
@@ -1874,7 +1874,7 @@ describe('ReactDOMFizzServer', () => {
     expect(loggedErrors).toEqual([]);
 
     // Error the content, but we don't have a fallback yet.
-    await act(async () => {
+    await act(() => {
       rejectText('Hello', theError);
     });
 
@@ -1885,7 +1885,7 @@ describe('ReactDOMFizzServer', () => {
     expect(getVisibleChildren(container)).toEqual('Loading root...');
 
     // Unblock the loading state
-    await act(async () => {
+    await act(() => {
       resolveText('Loading...');
     });
 
@@ -1929,7 +1929,7 @@ describe('ReactDOMFizzServer', () => {
   });
 
   it('should be able to abort the fallback if the main content finishes first', async () => {
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <Suspense fallback={<Text text="Loading Outer" />}>
           <div>
@@ -1950,7 +1950,7 @@ describe('ReactDOMFizzServer', () => {
     expect(getVisibleChildren(container)).toEqual('Loading Outer');
     // We should have received a partial segment containing the a partial of the fallback.
     expect(container.innerHTML).toContain('Inner');
-    await act(async () => {
+    await act(() => {
       resolveText('Hello');
     });
     // We should've been able to display the content without waiting for the rest of the fallback.
@@ -2026,7 +2026,7 @@ describe('ReactDOMFizzServer', () => {
 
     await jest.runAllTimers();
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App isClient={false} />);
       pipe(writable);
     });
@@ -2036,7 +2036,7 @@ describe('ReactDOMFizzServer', () => {
     expect(container.innerHTML).not.toContain('Avoided Fallback');
 
     // resolve first suspense component with avoidThisFallback
-    await act(async () => {
+    await act(() => {
       promiseRes[0]();
     });
 
@@ -2050,7 +2050,7 @@ describe('ReactDOMFizzServer', () => {
 
     expect(container.innerHTML).not.toContain('Avoided Fallback2');
 
-    await act(async () => {
+    await act(() => {
       promiseRes[1]();
     });
 
@@ -2136,7 +2136,7 @@ describe('ReactDOMFizzServer', () => {
     }
 
     const loggedErrors = [];
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <Suspense fallback="Loading...">
           <App />
@@ -2219,7 +2219,7 @@ describe('ReactDOMFizzServer', () => {
       );
     }
     const loggedErrors = [];
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <Suspense fallback="Loading...">
           <App />
@@ -2306,7 +2306,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -2396,7 +2396,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -2486,7 +2486,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -2539,7 +2539,7 @@ describe('ReactDOMFizzServer', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />, {
         onError(error) {
           Scheduler.log('[s!] ' + error.message);
@@ -2576,7 +2576,7 @@ describe('ReactDOMFizzServer', () => {
     expect(serverFallback).toBe(clientFallback);
 
     // When we're able to fully hydrate, we expect a clean client render.
-    await act(async () => {
+    await act(() => {
       resolveText('Yay!');
     });
     await waitForAll([
@@ -2624,7 +2624,7 @@ describe('ReactDOMFizzServer', () => {
           </div>
         );
       }
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App color="red" />, {
           onError(error) {
             Scheduler.log('[s!] ' + error.message);
@@ -2670,7 +2670,7 @@ describe('ReactDOMFizzServer', () => {
       expect(clientFallback2).toBe(serverFallback);
 
       // When we're able to fully hydrate, we expect a clean client render.
-      await act(async () => {
+      await act(() => {
         resolveText('Yay!');
       });
       await waitForAll([
@@ -2722,7 +2722,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(
           <App fallbackText="Loading..." />,
           {
@@ -2784,7 +2784,7 @@ describe('ReactDOMFizzServer', () => {
       expect(clientFallback2).not.toBe(clientFallback1);
 
       // Verify we can still do a clean content render after.
-      await act(async () => {
+      await act(() => {
         resolveText('Yay!');
       });
       await waitForAll(['Yay!']);
@@ -2851,7 +2851,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -2883,7 +2883,7 @@ describe('ReactDOMFizzServer', () => {
         </div>,
       );
 
-      await act(async () => {
+      await act(() => {
         resolveText('Yay!');
       });
       await waitForAll(['Yay!']);
@@ -3001,7 +3001,7 @@ describe('ReactDOMFizzServer', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />);
       pipe(writable);
     });
@@ -3065,7 +3065,7 @@ describe('ReactDOMFizzServer', () => {
       return <span>{context}</span>;
     }
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<Foo />);
       pipe(writable);
     });
@@ -3087,7 +3087,7 @@ describe('ReactDOMFizzServer', () => {
       {name: 'b', value: 'b'},
     ]).map(item => <li key={item.get('value')}>{item.get('name')}</li>);
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<ul>{mappedJSX}</ul>);
       pipe(writable);
     });
@@ -3119,7 +3119,7 @@ describe('ReactDOMFizzServer', () => {
 
     let abort;
     const loggedErrors = [];
-    await act(async () => {
+    await act(() => {
       const {pipe, abort: abortImpl} = renderToPipeableStream(<App />, {
         onError(error) {
           // In this test we contrive erroring with strings so we push the error whereas in most
@@ -3202,7 +3202,7 @@ describe('ReactDOMFizzServer', () => {
 
     let abort;
     const loggedErrors = [];
-    await act(async () => {
+    await act(() => {
       const {pipe, abort: abortImpl} = renderToPipeableStream(<App />, {
         onError(error) {
           loggedErrors.push(error.message);
@@ -3264,7 +3264,7 @@ describe('ReactDOMFizzServer', () => {
   });
 
   it('warns in dev if you access digest from errorInfo in onRecoverableError', async () => {
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(
         <div>
           <Suspense fallback={'loading...'}>
@@ -3341,7 +3341,7 @@ describe('ReactDOMFizzServer', () => {
         )}`;
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />, {
           onError,
         });
@@ -3389,7 +3389,7 @@ describe('ReactDOMFizzServer', () => {
         )}`;
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />, {
           onError,
         });
@@ -3429,7 +3429,7 @@ describe('ReactDOMFizzServer', () => {
       const expectedDigest = onError(theError);
       loggedErrors.length = 0;
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />, {
           onError,
         });
@@ -3529,7 +3529,7 @@ describe('ReactDOMFizzServer', () => {
       window.__test_outlet = '';
       const stringWithScriptsInIt =
         'prescription pre<scription pre<Scription pre</scRipTion pre</ScripTion </script><script><!-- <script> -->';
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<div />, {
           bootstrapScriptContent:
             'window.__test_outlet = "This should have been replaced";var x = "' +
@@ -3550,7 +3550,7 @@ describe('ReactDOMFizzServer', () => {
       const el = document.createElement('p');
       el.textContent = '{"one":1,\u2028\u2029"two":2}';
       const stringWithLSAndPSCharacters = el.textContent;
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<div />, {
           bootstrapScriptContent:
             'let x = ' +
@@ -3571,7 +3571,7 @@ describe('ReactDOMFizzServer', () => {
       window.__test_outlet = null;
       // this boolean expression will be cast to a number due to the bitwise &. we will look for a truthy value (1) below
       const booleanLogicString = '1 < 2 & 3 > 1';
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<div />, {
           bootstrapScriptContent:
             'let x = ' + booleanLogicString + '; window.__test_outlet = x;',
@@ -3635,7 +3635,7 @@ describe('ReactDOMFizzServer', () => {
       const {pipe} = renderToPipeableStream(<App />);
       pipe(writable);
     });
-    await act(async () => {
+    await act(() => {
       resolveText('Hello');
     });
 
@@ -3696,7 +3696,7 @@ describe('ReactDOMFizzServer', () => {
     };
 
     const [ServerApp, serverResolve] = makeApp();
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<ServerApp />);
       pipe(writable);
     });
@@ -3770,7 +3770,7 @@ describe('ReactDOMFizzServer', () => {
     };
 
     const [ServerApp, serverResolve] = makeApp();
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<ServerApp text="initial" />);
       pipe(writable);
     });
@@ -3845,7 +3845,7 @@ describe('ReactDOMFizzServer', () => {
     };
 
     try {
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App text="initial" />);
         pipe(writable);
       });
@@ -3932,7 +3932,7 @@ describe('ReactDOMFizzServer', () => {
       );
     };
 
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />);
       pipe(writable);
     });
@@ -4022,7 +4022,7 @@ describe('ReactDOMFizzServer', () => {
     };
 
     try {
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -4151,7 +4151,7 @@ describe('ReactDOMFizzServer', () => {
     };
 
     try {
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -4272,7 +4272,7 @@ describe('ReactDOMFizzServer', () => {
     };
 
     try {
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -4341,7 +4341,7 @@ describe('ReactDOMFizzServer', () => {
         </Suspense>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />);
       pipe(writable);
     });
@@ -4387,7 +4387,7 @@ describe('ReactDOMFizzServer', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = renderToPipeableStream(<App />);
       pipe(writable);
     });
@@ -4540,7 +4540,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App name="Foo" />);
         pipe(writable);
       });
@@ -4578,7 +4578,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App name="Foo" />);
         pipe(writable);
       });
@@ -4638,7 +4638,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -4831,7 +4831,7 @@ describe('ReactDOMFizzServer', () => {
         '<div id="app-div">start<!--$?--><template id="B:0"></template>[loading first]<!--/$--><!--$?--><template id="B:1"></template>[loading second]<!--/$-->end</div>',
       );
 
-      await act(async () => {
+      await act(() => {
         resolveText('first suspended');
       });
 
@@ -4858,7 +4858,7 @@ describe('ReactDOMFizzServer', () => {
         </div>,
       );
 
-      await act(async () => {
+      await act(() => {
         resolveText('second suspended');
       });
 
@@ -4961,7 +4961,7 @@ describe('ReactDOMFizzServer', () => {
       }
 
       prepareJSDOMForTitle();
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -4985,7 +4985,7 @@ describe('ReactDOMFizzServer', () => {
       }
 
       prepareJSDOMForTitle();
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -5010,7 +5010,7 @@ describe('ReactDOMFizzServer', () => {
       prepareJSDOMForTitle();
 
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           const {pipe} = renderToPipeableStream(<App />);
           pipe(writable);
         });
@@ -5072,7 +5072,7 @@ describe('ReactDOMFizzServer', () => {
 
       if (gate(flags => flags.enableFloat)) {
         await expect(async () => {
-          await act(async () => {
+          await act(() => {
             const {pipe} = renderToPipeableStream(<App />);
             pipe(writable);
           });
@@ -5081,7 +5081,7 @@ describe('ReactDOMFizzServer', () => {
         ]);
       } else {
         await expect(async () => {
-          await act(async () => {
+          await act(() => {
             const {pipe} = renderToPipeableStream(<App />);
             pipe(writable);
           });
@@ -5135,7 +5135,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -5195,7 +5195,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -5234,7 +5234,7 @@ describe('ReactDOMFizzServer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -5303,7 +5303,7 @@ describe('ReactDOMFizzServer', () => {
       }
 
       const reportedServerErrors = [];
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />, {
           onError(error) {
             reportedServerErrors.push(error);
@@ -5364,7 +5364,7 @@ describe('ReactDOMFizzServer', () => {
         return use(thenable);
       }
 
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -5395,7 +5395,7 @@ describe('ReactDOMFizzServer', () => {
       }
       // Because the thenable resolves synchronously, we should be able to finish
       // rendering synchronously, with no fallback.
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -5418,7 +5418,7 @@ describe('ReactDOMFizzServer', () => {
           </button>
         );
       }
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
@@ -5449,7 +5449,7 @@ describe('ReactDOMFizzServer', () => {
       const reportedServerErrors = [];
       let caughtError;
       try {
-        await act(async () => {
+        await act(() => {
           const {pipe} = renderToPipeableStream(<App />, {
             onError(e) {
               reportedServerErrors.push(e);
@@ -5478,7 +5478,7 @@ describe('ReactDOMFizzServer', () => {
           return <span />;
         }
       }
-      await act(async () => {
+      await act(() => {
         const {pipe} = renderToPipeableStream(<App />);
         pipe(writable);
       });
diff --git a/packages/react-dom/src/__tests__/ReactDOMFizzSuppressHydrationWarning-test.js b/packages/react-dom/src/__tests__/ReactDOMFizzSuppressHydrationWarning-test.js
index 28796171aefb0..b77c88ca5081b 100644
--- a/packages/react-dom/src/__tests__/ReactDOMFizzSuppressHydrationWarning-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMFizzSuppressHydrationWarning-test.js
@@ -141,7 +141,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -180,7 +180,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -220,7 +220,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -271,7 +271,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -307,7 +307,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -353,7 +353,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -404,7 +404,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -453,7 +453,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -509,7 +509,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -546,7 +546,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -579,7 +579,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
@@ -624,7 +624,7 @@ describe('ReactDOMFizzServerHydrationWarning', () => {
         </div>
       );
     }
-    await act(async () => {
+    await act(() => {
       const {pipe} = ReactDOMFizzServer.renderToPipeableStream(
         <App isClient={false} />,
       );
diff --git a/packages/react-dom/src/__tests__/ReactDOMHooks-test.js b/packages/react-dom/src/__tests__/ReactDOMHooks-test.js
index aaaf5c5044497..c8695de60b7e5 100644
--- a/packages/react-dom/src/__tests__/ReactDOMHooks-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMHooks-test.js
@@ -135,7 +135,7 @@ describe('ReactDOMHooks', () => {
     Scheduler.unstable_flushAll();
 
     inputRef.current.value = 'abc';
-    await act(async () => {
+    await act(() => {
       inputRef.current.dispatchEvent(
         new Event('input', {
           bubbles: true,
diff --git a/packages/react-dom/src/__tests__/ReactDOMNativeEventHeuristic-test.js b/packages/react-dom/src/__tests__/ReactDOMNativeEventHeuristic-test.js
index a03b8c80ff921..9f82e730f8137 100644
--- a/packages/react-dom/src/__tests__/ReactDOMNativeEventHeuristic-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMNativeEventHeuristic-test.js
@@ -74,7 +74,7 @@ describe('ReactDOMNativeEventHeuristic-test', () => {
     }
 
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Form />);
     });
 
@@ -231,12 +231,12 @@ describe('ReactDOMNativeEventHeuristic-test', () => {
       return <div ref={target}>{isHover ? 'hovered' : 'not hovered'}</div>;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Foo />);
     });
     expect(container.textContent).toEqual('not hovered');
 
-    await act(async () => {
+    await act(() => {
       const mouseOverEvent = document.createEvent('MouseEvents');
       mouseOverEvent.initEvent('mouseover', true, true);
       dispatchAndSetCurrentEvent(target.current, mouseOverEvent);
@@ -261,12 +261,12 @@ describe('ReactDOMNativeEventHeuristic-test', () => {
       return <div ref={target}>{isHover ? 'hovered' : 'not hovered'}</div>;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Foo />);
     });
     expect(container.textContent).toEqual('not hovered');
 
-    await act(async () => {
+    await act(() => {
       // Note: React does not use native mouseenter/mouseleave events
       // but we should still correctly determine their priority.
       const mouseEnterEvent = document.createEvent('MouseEvents');
@@ -291,7 +291,7 @@ describe('ReactDOMNativeEventHeuristic-test', () => {
       return <div ref={target}>{hoverString}</div>;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Foo hovered={false} />);
     });
     expect(container.textContent).toEqual('not hovered');
@@ -337,7 +337,7 @@ describe('ReactDOMNativeEventHeuristic-test', () => {
       return <div ref={target}>Count: {count}</div>;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Foo />);
     });
     expect(container.textContent).toEqual('Count: 0');
@@ -378,7 +378,7 @@ describe('ReactDOMNativeEventHeuristic-test', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Foo />);
     });
     expect(container.textContent).toEqual('Count: 0');
diff --git a/packages/react-dom/src/__tests__/ReactDOMNestedEvents-test.js b/packages/react-dom/src/__tests__/ReactDOMNestedEvents-test.js
index 881077b498a84..f7b0db175e5f6 100644
--- a/packages/react-dom/src/__tests__/ReactDOMNestedEvents-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMNestedEvents-test.js
@@ -59,14 +59,14 @@ describe('ReactDOMNestedEvents', () => {
     document.body.appendChild(container);
     const root = ReactDOMClient.createRoot(container);
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     expect(buttonRef.current.innerHTML).toEqual(
       'Clicked: false, Focused: false',
     );
 
-    await act(async () => {
+    await act(() => {
       buttonRef.current.click();
     });
     assertLog(['Value right after focus call: Clicked: false, Focused: false']);
diff --git a/packages/react-dom/src/__tests__/ReactDOMRoot-test.js b/packages/react-dom/src/__tests__/ReactDOMRoot-test.js
index b81d1cdc30036..3352d72c8b91f 100644
--- a/packages/react-dom/src/__tests__/ReactDOMRoot-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMRoot-test.js
@@ -398,7 +398,7 @@ describe('ReactDOMRoot', () => {
       return <div>{value}</div>;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Foo value="a" />);
     });
 
@@ -422,12 +422,12 @@ describe('ReactDOMRoot', () => {
 
   it('unmount is synchronous', async () => {
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render('Hi');
     });
     expect(container.textContent).toEqual('Hi');
 
-    await act(async () => {
+    await act(() => {
       root.unmount();
       // Should have already unmounted
       expect(container.textContent).toEqual('');
@@ -436,7 +436,7 @@ describe('ReactDOMRoot', () => {
 
   it('throws if an unmounted root is updated', async () => {
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render('Hi');
     });
     expect(container.textContent).toEqual('Hi');
@@ -463,7 +463,7 @@ describe('ReactDOMRoot', () => {
       return 'Hi';
     }
 
-    await act(async () => {
+    await act(() => {
       root1.render(<App step={1} />);
     });
     expect(container1.textContent).toEqual('Hi');
diff --git a/packages/react-dom/src/__tests__/ReactDOMSafariMicrotaskBug-test.js b/packages/react-dom/src/__tests__/ReactDOMSafariMicrotaskBug-test.js
index 9c7fb089b9908..f4edb90e1fb4a 100644
--- a/packages/react-dom/src/__tests__/ReactDOMSafariMicrotaskBug-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMSafariMicrotaskBug-test.js
@@ -66,7 +66,7 @@ describe('ReactDOMSafariMicrotaskBug-test', () => {
       );
     }
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Foo />);
     });
     expect(container.textContent).toBe('1');
@@ -86,11 +86,11 @@ describe('ReactDOMSafariMicrotaskBug-test', () => {
       );
     }
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Foo />);
     });
     expect(container.textContent).toBe('0');
-    await act(async () => {
+    await act(() => {
       container.firstChild.dispatchEvent(
         new MouseEvent('click', {bubbles: true}),
       );
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js b/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
index bf433b50b5433..61565a175839a 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js
@@ -454,7 +454,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(deleted.length).toBe(0);
 
     // Performing an update should force it to delete the boundary
-    await act(async () => {
+    await act(() => {
       root.render(<App value={true} />);
     });
 
@@ -510,7 +510,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(ref.current).toBe(null);
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactDOMClient.hydrateRoot(container, <App hasB={false} />, {
           onRecoverableError(error) {
             Scheduler.log(error.message);
@@ -579,7 +579,7 @@ describe('ReactDOMServerPartialHydration', () => {
       expect(ref.current).toBe(null);
 
       shouldSuspend = true;
-      await act(async () => {
+      await act(() => {
         ReactDOMClient.hydrateRoot(container, <App hasB={false} />);
       });
 
@@ -636,7 +636,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(ref.current).toBe(null);
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactDOMClient.hydrateRoot(container, <App hasB={false} />, {
           onRecoverableError(error) {
             Scheduler.log(error.message);
@@ -698,7 +698,7 @@ describe('ReactDOMServerPartialHydration', () => {
 
     expect(deleted.length).toBe(0);
 
-    await act(async () => {
+    await act(() => {
       root.render(<App deleted={true} />);
     });
 
@@ -744,7 +744,7 @@ describe('ReactDOMServerPartialHydration', () => {
     // On the client we try to hydrate.
     suspend = true;
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactDOM.hydrate(<App />, container);
       });
     }).toErrorDev(
@@ -829,14 +829,14 @@ describe('ReactDOMServerPartialHydration', () => {
     // hydrating anyway.
     suspend = true;
 
-    await act(async () => {
+    await act(() => {
       ReactDOMClient.hydrateRoot(container, <App />);
     });
 
     expect(container.firstChild.firstChild.tagName).not.toBe('DIV');
 
     // In this state, we can still update the siblings.
-    await act(async () => showSibling());
+    await act(() => showSibling());
 
     expect(container.firstChild.firstChild.tagName).toBe('DIV');
     expect(container.firstChild.firstChild.textContent).toBe('First');
@@ -885,14 +885,14 @@ describe('ReactDOMServerPartialHydration', () => {
     // On the client we don't have all data yet but we want to start
     // hydrating anyway.
     suspend = true;
-    await act(async () => {
+    await act(() => {
       ReactDOMClient.hydrateRoot(container, <App />);
     });
 
     expect(container.firstChild.children[1].textContent).toBe('Middle');
 
     // In this state, we can still delete the boundary.
-    await act(async () => hideMiddle());
+    await act(() => hideMiddle());
 
     expect(container.firstChild.children[1].textContent).toBe('After');
   });
@@ -1096,7 +1096,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(ref.current).toBe(null);
 
     // Render an update, but leave it still suspended.
-    await act(async () => {
+    await act(() => {
       root.render(<App text="Hi" className="hi" />);
     });
 
@@ -1177,7 +1177,7 @@ describe('ReactDOMServerPartialHydration', () => {
 
     // Render an update, but leave it still suspended.
     // Flushing now should delete the existing content and show the fallback.
-    await act(async () => {
+    await act(() => {
       root.render(<App text="Hi" className="hi" />);
     });
 
@@ -1253,7 +1253,7 @@ describe('ReactDOMServerPartialHydration', () => {
 
     // Render an update, but leave it still suspended.
     // Flushing now should delete the existing content and show the fallback.
-    await act(async () => {
+    await act(() => {
       root.render(<App text="Hi" className="hi" />);
     });
 
@@ -1570,7 +1570,7 @@ describe('ReactDOMServerPartialHydration', () => {
 
     // Render an update, but leave it still suspended.
     // Flushing now should delete the existing content and show the fallback.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Context.Provider value={{text: 'Hi', className: 'hi'}}>
           <App />
@@ -1880,7 +1880,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(container.textContent).toBe('AB');
 
     // Add more rows before we've hydrated the first two.
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={true} />);
     });
 
@@ -2313,7 +2313,7 @@ describe('ReactDOMServerPartialHydration', () => {
     // The new update doesn't suspend.
     // Since we're still suspended on the original data, we can't hydrate.
     // This will force all expiration times to flush.
-    await act(async () => {
+    await act(() => {
       root.render(
         <ClassName.Provider value={'hi'}>
           <App text="Hi" />
@@ -2395,7 +2395,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(container.textContent).toBe('Click meHello');
 
     // We're now partially hydrated.
-    await act(async () => {
+    await act(() => {
       a.click();
     });
     expect(clicks).toBe(0);
@@ -2486,7 +2486,7 @@ describe('ReactDOMServerPartialHydration', () => {
     jest.runAllTimers();
 
     // We're now partially hydrated.
-    await act(async () => {
+    await act(() => {
       a.click();
     });
     // We should not have invoked the event yet because we're not
@@ -2568,7 +2568,7 @@ describe('ReactDOMServerPartialHydration', () => {
     ReactDOMClient.hydrateRoot(container, <App />);
 
     // We'll do one click before hydrating.
-    await act(async () => {
+    await act(() => {
       a.click();
     });
     // This should be delayed.
@@ -2578,7 +2578,7 @@ describe('ReactDOMServerPartialHydration', () => {
     jest.runAllTimers();
 
     // We're now partially hydrated.
-    await act(async () => {
+    await act(() => {
       a.click();
     });
     expect(clicks).toBe(0);
@@ -2671,7 +2671,7 @@ describe('ReactDOMServerPartialHydration', () => {
     jest.runAllTimers();
 
     // We're now partially hydrated.
-    await act(async () => {
+    await act(() => {
       a.click();
     });
     // We should not have invoked the event yet because we're not
@@ -2752,7 +2752,7 @@ describe('ReactDOMServerPartialHydration', () => {
     jest.runAllTimers();
 
     // We're now partially hydrated.
-    await act(async () => {
+    await act(() => {
       span.click();
     });
     expect(clicksOnChild).toBe(0);
@@ -2840,7 +2840,7 @@ describe('ReactDOMServerPartialHydration', () => {
     Scheduler.unstable_flushAll();
 
     // The Suspense boundary is not yet hydrated.
-    await act(async () => {
+    await act(() => {
       a.click();
     });
     expect(clicks).toBe(0);
@@ -3115,7 +3115,7 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(container.textContent).toBe('Click meHello');
 
     // We're now partially hydrated.
-    await act(async () => {
+    await act(() => {
       form.dispatchEvent(
         new window.Event('submit', {
           bubbles: true,
@@ -3415,7 +3415,7 @@ describe('ReactDOMServerPartialHydration', () => {
     container.innerHTML = finalHTML;
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactDOMClient.hydrateRoot(container, <App isClient={true} />, {
           onRecoverableError(error) {
             Scheduler.log('Log recoverable error: ' + error.message);
@@ -3462,7 +3462,7 @@ describe('ReactDOMServerPartialHydration', () => {
       <DirectTextChild text="good" />,
     );
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactDOMClient.hydrateRoot(container, <DirectTextChild text="bad" />, {
           onRecoverableError(error) {
             Scheduler.log(error.message);
@@ -3503,7 +3503,7 @@ describe('ReactDOMServerPartialHydration', () => {
       <TextChildWithSibling text="good" />,
     );
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactDOMClient.hydrateRoot(
           container2,
           <TextChildWithSibling text="bad" />,
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerSelectiveHydration-test.internal.js b/packages/react-dom/src/__tests__/ReactDOMServerSelectiveHydration-test.internal.js
index 62cd50fdfb3b6..ede800787b044 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerSelectiveHydration-test.internal.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerSelectiveHydration-test.internal.js
@@ -276,7 +276,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
     assertLog([]);
 
     // This click target cannot be hydrated yet because it's suspended.
-    await act(async () => {
+    await act(() => {
       const result = dispatchClickEvent(spanD);
       expect(result).toBe(true);
     });
@@ -558,7 +558,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
     assertLog([]);
 
     // Continuing rendering will render B next.
-    await act(async () => {
+    await act(() => {
       const target = createEventTarget(spanD);
       target.virtualclick();
     });
@@ -1110,7 +1110,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
 
       dispatchClickEvent(innerDiv);
 
-      await act(async () => {
+      await act(() => {
         jest.runAllTimers();
         Scheduler.unstable_flushAllWithoutAsserting();
         OuterScheduler.unstable_flushAllWithoutAsserting();
@@ -1181,7 +1181,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
       assertLog([]);
 
       // fire scheduled Replay
-      await act(async () => {
+      await act(() => {
         jest.runAllTimers();
         Scheduler.unstable_flushAllWithoutAsserting();
         OuterScheduler.unstable_flushAllWithoutAsserting();
@@ -1210,7 +1210,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
       expect(InnerScheduler.unstable_clearLog()).toEqual([]);
 
       // Replay outer event
-      await act(async () => {
+      await act(() => {
         Scheduler.unstable_flushAllWithoutAsserting();
         OuterScheduler.unstable_flushAllWithoutAsserting();
         InnerScheduler.unstable_flushAllWithoutAsserting();
@@ -1240,7 +1240,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
       // Outer was hydrated earlier
       expect(OuterScheduler.unstable_clearLog()).toEqual([]);
 
-      await act(async () => {
+      await act(() => {
         Scheduler.unstable_flushAllWithoutAsserting();
         OuterScheduler.unstable_flushAllWithoutAsserting();
         InnerScheduler.unstable_flushAllWithoutAsserting();
@@ -1812,7 +1812,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
     const root = ReactDOMClient.hydrateRoot(container, <App text="A" />);
     await waitForPaint(['App A']);
 
-    await act(async () => {
+    await act(() => {
       ReactDOM.flushSync(() => {
         root.render(<App text="B" />);
       });
@@ -1848,7 +1848,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
     const root = ReactDOMClient.hydrateRoot(container, <App text="A" />);
     await waitForPaint(['App A']);
 
-    await act(async () => {
+    await act(() => {
       TODO_scheduleContinuousSchedulerTask(() => {
         root.render(<App text="B" />);
       });
@@ -1883,7 +1883,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
     const initialSpan = container.getElementsByTagName('span')[0];
     const root = ReactDOMClient.hydrateRoot(container, <App text="A" />);
     await waitForPaint(['App A']);
-    await act(async () => {
+    await act(() => {
       root.render(<App text="B" />);
     });
     assertLog(['App B', 'Child A', 'App B', 'Child B']);
diff --git a/packages/react-dom/src/__tests__/ReactDOMServerSuspense-test.internal.js b/packages/react-dom/src/__tests__/ReactDOMServerSuspense-test.internal.js
index 2e986c332a38d..8bf03548ce959 100644
--- a/packages/react-dom/src/__tests__/ReactDOMServerSuspense-test.internal.js
+++ b/packages/react-dom/src/__tests__/ReactDOMServerSuspense-test.internal.js
@@ -161,7 +161,7 @@ describe('ReactDOMServerSuspense', () => {
     expect(divB.tagName).toBe('DIV');
     expect(divB.textContent).toBe('B');
 
-    await act(async () => {
+    await act(() => {
       ReactDOMClient.hydrateRoot(parent, example);
     });
 
diff --git a/packages/react-dom/src/__tests__/ReactDOMSuspensePlaceholder-test.js b/packages/react-dom/src/__tests__/ReactDOMSuspensePlaceholder-test.js
index c85d153fb461c..0a9e78fd8c225 100644
--- a/packages/react-dom/src/__tests__/ReactDOMSuspensePlaceholder-test.js
+++ b/packages/react-dom/src/__tests__/ReactDOMSuspensePlaceholder-test.js
@@ -182,7 +182,7 @@ describe('ReactDOMSuspensePlaceholder', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<App />, container);
       });
       expect(container.innerHTML).toEqual(
@@ -192,14 +192,14 @@ describe('ReactDOMSuspensePlaceholder', () => {
 
       // Update the inline display style. It will be overridden because it's
       // inside a hidden fallback.
-      await act(async () => setIsVisible(true));
+      await act(() => setIsVisible(true));
       expect(container.innerHTML).toEqual(
         '<span style="display: none;">Sibling</span><span style=' +
           '"display: none;"></span>Loading...',
       );
 
       // Unsuspend. The style should now match the inline prop.
-      await act(async () => resolveText('Async'));
+      await act(() => resolveText('Async'));
       expect(container.innerHTML).toEqual(
         '<span style="display: inline;">Sibling</span><span style="">Async</span>',
       );
diff --git a/packages/react-dom/src/__tests__/ReactErrorBoundaries-test.internal.js b/packages/react-dom/src/__tests__/ReactErrorBoundaries-test.internal.js
index 7b9eb15326762..04cb8bbc1e492 100644
--- a/packages/react-dom/src/__tests__/ReactErrorBoundaries-test.internal.js
+++ b/packages/react-dom/src/__tests__/ReactErrorBoundaries-test.internal.js
@@ -1864,7 +1864,7 @@ describe('ReactErrorBoundaries', () => {
 
   it('catches errors in useEffect', async () => {
     const container = document.createElement('div');
-    await act(async () => {
+    await act(() => {
       ReactDOM.render(
         <ErrorBoundary>
           <BrokenUseEffect>Initial value</BrokenUseEffect>
diff --git a/packages/react-dom/src/__tests__/ReactUpdates-test.js b/packages/react-dom/src/__tests__/ReactUpdates-test.js
index 56c2db3b724cb..ef9766da96746 100644
--- a/packages/react-dom/src/__tests__/ReactUpdates-test.js
+++ b/packages/react-dom/src/__tests__/ReactUpdates-test.js
@@ -1678,11 +1678,11 @@ describe('ReactUpdates', () => {
       }
 
       const container = document.createElement('div');
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<Terminating />, container);
       });
       expect(container.textContent).toBe('50');
-      await act(async () => {
+      await act(() => {
         _setStep(0);
       });
       expect(container.textContent).toBe('50');
@@ -1701,7 +1701,7 @@ describe('ReactUpdates', () => {
       }
 
       const container = document.createElement('div');
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(<Terminating />, container);
       });
 
diff --git a/packages/react-dom/src/__tests__/ReactWrongReturnPointer-test.js b/packages/react-dom/src/__tests__/ReactWrongReturnPointer-test.js
index a329d300b7e9a..831c8a7d85784 100644
--- a/packages/react-dom/src/__tests__/ReactWrongReturnPointer-test.js
+++ b/packages/react-dom/src/__tests__/ReactWrongReturnPointer-test.js
@@ -189,15 +189,15 @@ test('regression (#20932): return pointer is correct before entering deleted tre
   }
 
   const root = ReactNoop.createRoot();
-  await act(async () => {
+  await act(() => {
     root.render(<App />);
   });
   assertLog(['Suspend! [0]', 'Loading Async...', 'Loading Tail...']);
-  await act(async () => {
+  await act(() => {
     resolveText(0);
   });
   assertLog([0, 'Tail']);
-  await act(async () => {
+  await act(() => {
     setAsyncText(x => x + 1);
   });
   assertLog([
diff --git a/packages/react-dom/src/__tests__/utils/ReactDOMServerIntegrationTestUtils.js b/packages/react-dom/src/__tests__/utils/ReactDOMServerIntegrationTestUtils.js
index f4a35184bcafc..8392b57af03cf 100644
--- a/packages/react-dom/src/__tests__/utils/ReactDOMServerIntegrationTestUtils.js
+++ b/packages/react-dom/src/__tests__/utils/ReactDOMServerIntegrationTestUtils.js
@@ -50,11 +50,11 @@ module.exports = function (initModules) {
   // promisified version of ReactDOM.render()
   async function asyncReactDOMRender(reactElement, domElement, forceHydrate) {
     if (forceHydrate) {
-      await act(async () => {
+      await act(() => {
         ReactDOM.hydrate(reactElement, domElement);
       });
     } else {
-      await act(async () => {
+      await act(() => {
         ReactDOM.render(reactElement, domElement);
       });
     }
diff --git a/packages/react-dom/src/events/__tests__/DOMPluginEventSystem-test.internal.js b/packages/react-dom/src/events/__tests__/DOMPluginEventSystem-test.internal.js
index 7b06794d62a41..37aac3c9a985c 100644
--- a/packages/react-dom/src/events/__tests__/DOMPluginEventSystem-test.internal.js
+++ b/packages/react-dom/src/events/__tests__/DOMPluginEventSystem-test.internal.js
@@ -652,7 +652,7 @@ describe('DOMPluginEventSystem', () => {
           Scheduler.unstable_flushAll();
 
           // The Suspense boundary is not yet hydrated.
-          await act(async () => {
+          await act(() => {
             a.click();
           });
           expect(clicks).toBe(0);
@@ -703,14 +703,14 @@ describe('DOMPluginEventSystem', () => {
             );
           }
 
-          await act(async () => {
+          await act(() => {
             ReactDOM.render(<Parent />, container);
           });
 
           const parent = container.lastChild;
           expect(parent.id).toEqual('parent');
 
-          await act(async () => {
+          await act(() => {
             dispatchClickEvent(parent);
           });
 
@@ -719,7 +719,7 @@ describe('DOMPluginEventSystem', () => {
           const child = parent.lastChild;
           expect(child.id).toEqual('child');
 
-          await act(async () => {
+          await act(() => {
             dispatchClickEvent(child);
           });
 
@@ -752,14 +752,14 @@ describe('DOMPluginEventSystem', () => {
             );
           }
 
-          await act(async () => {
+          await act(() => {
             ReactDOM.render(<Parent />, container);
           });
 
           const parent = container.lastChild;
           expect(parent.id).toEqual('parent');
 
-          await act(async () => {
+          await act(() => {
             dispatchClickEvent(parent);
           });
 
@@ -768,7 +768,7 @@ describe('DOMPluginEventSystem', () => {
           const child = parent.lastChild;
           expect(child.id).toEqual('child');
 
-          await act(async () => {
+          await act(() => {
             dispatchClickEvent(child);
           });
 
@@ -2575,7 +2575,7 @@ describe('DOMPluginEventSystem', () => {
 
             const root = ReactDOMClient.createRoot(container2);
 
-            await act(async () => {
+            await act(() => {
               root.render(<Component />);
             });
             jest.runAllTimers();
@@ -2587,7 +2587,7 @@ describe('DOMPluginEventSystem', () => {
             expect(onAfterBlur).toHaveBeenCalledTimes(0);
 
             suspend = true;
-            await act(async () => {
+            await act(() => {
               root.render(<Component />);
             });
             jest.runAllTimers();
@@ -2661,7 +2661,7 @@ describe('DOMPluginEventSystem', () => {
 
             const root = ReactDOMClient.createRoot(container2);
 
-            await act(async () => {
+            await act(() => {
               root.render(<Component />);
             });
             jest.runAllTimers();
@@ -2672,7 +2672,7 @@ describe('DOMPluginEventSystem', () => {
             expect(onBeforeBlur).toHaveBeenCalledTimes(0);
 
             suspend = true;
-            await act(async () => {
+            await act(() => {
               root.render(<Component />);
             });
             jest.runAllTimers();
@@ -2726,7 +2726,7 @@ describe('DOMPluginEventSystem', () => {
             document.body.appendChild(container2);
 
             const root = ReactDOMClient.createRoot(container2);
-            await act(async () => {
+            await act(() => {
               root.render(<Component />);
             });
 
@@ -2737,7 +2737,7 @@ describe('DOMPluginEventSystem', () => {
 
             // Suspend. This hides the input node, causing it to lose focus.
             suspend = true;
-            await act(async () => {
+            await act(() => {
               root.render(<Component />);
             });
 
diff --git a/packages/react-dom/src/events/plugins/__tests__/ChangeEventPlugin-test.js b/packages/react-dom/src/events/plugins/__tests__/ChangeEventPlugin-test.js
index 5ea94e056fc16..ccc69785e6bea 100644
--- a/packages/react-dom/src/events/plugins/__tests__/ChangeEventPlugin-test.js
+++ b/packages/react-dom/src/events/plugins/__tests__/ChangeEventPlugin-test.js
@@ -753,12 +753,12 @@ describe('ChangeEventPlugin', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         root.render(<Foo />);
       });
       expect(container.textContent).toEqual('not hovered');
 
-      await act(async () => {
+      await act(() => {
         const mouseOverEvent = document.createEvent('MouseEvents');
         mouseOverEvent.initEvent('mouseover', true, true);
         target.current.dispatchEvent(mouseOverEvent);
diff --git a/packages/react-dom/src/events/plugins/__tests__/SimpleEventPlugin-test.js b/packages/react-dom/src/events/plugins/__tests__/SimpleEventPlugin-test.js
index 9cfddd9ca8779..5479f5192d1fb 100644
--- a/packages/react-dom/src/events/plugins/__tests__/SimpleEventPlugin-test.js
+++ b/packages/react-dom/src/events/plugins/__tests__/SimpleEventPlugin-test.js
@@ -301,7 +301,7 @@ describe('SimpleEventPlugin', function () {
       }
 
       // Click the button to trigger the side-effect
-      await act(async () => click());
+      await act(() => click());
       assertLog([
         // The handler fired
         'Side-effect',
@@ -370,17 +370,17 @@ describe('SimpleEventPlugin', function () {
       }
 
       // Click the button a single time
-      await act(async () => click());
+      await act(() => click());
       // The counter should update synchronously, even in concurrent mode.
       expect(button.textContent).toEqual('Count: 1');
 
       // Click the button many more times
-      await act(async () => click());
-      await act(async () => click());
-      await act(async () => click());
-      await act(async () => click());
-      await act(async () => click());
-      await act(async () => click());
+      await act(() => click());
+      await act(() => click());
+      await act(() => click());
+      await act(() => click());
+      await act(() => click());
+      await act(() => click());
 
       // Flush the remaining work
       await waitForAll([]);
diff --git a/packages/react-interactions/events/src/dom/create-event-handle/__tests__/useFocusWithin-test.internal.js b/packages/react-interactions/events/src/dom/create-event-handle/__tests__/useFocusWithin-test.internal.js
index 9199f24b0a8a0..dc76565c30a73 100644
--- a/packages/react-interactions/events/src/dom/create-event-handle/__tests__/useFocusWithin-test.internal.js
+++ b/packages/react-interactions/events/src/dom/create-event-handle/__tests__/useFocusWithin-test.internal.js
@@ -312,7 +312,7 @@ describe.each(table)(`useFocus`, hasPointerEvents => {
         </div>
       );
     };
-    await act(async () => {
+    await act(() => {
       ReactDOM.render(<Component />, container);
     });
 
@@ -508,7 +508,7 @@ describe.each(table)(`useFocus`, hasPointerEvents => {
 
       const root = ReactDOMClient.createRoot(container2);
 
-      await act(async () => {
+      await act(() => {
         root.render(<Component />);
       });
       jest.runAllTimers();
@@ -522,7 +522,7 @@ describe.each(table)(`useFocus`, hasPointerEvents => {
       expect(onAfterBlurWithin).toHaveBeenCalledTimes(0);
 
       suspend = true;
-      await act(async () => {
+      await act(() => {
         root.render(<Component />);
       });
       jest.runAllTimers();
@@ -567,7 +567,7 @@ describe.each(table)(`useFocus`, hasPointerEvents => {
 
       const root = ReactDOMClient.createRoot(container2);
 
-      await act(async () => {
+      await act(() => {
         root.render(<Component />);
       });
       jest.runAllTimers();
@@ -576,14 +576,14 @@ describe.each(table)(`useFocus`, hasPointerEvents => {
       expect(onAfterBlurWithin).toHaveBeenCalledTimes(0);
 
       suspend = true;
-      await act(async () => {
+      await act(() => {
         root.render(<Component />);
       });
       jest.runAllTimers();
       expect(onBeforeBlurWithin).toHaveBeenCalledTimes(0);
       expect(onAfterBlurWithin).toHaveBeenCalledTimes(0);
 
-      await act(async () => {
+      await act(() => {
         root.render(<Component />);
       });
       jest.runAllTimers();
@@ -592,7 +592,7 @@ describe.each(table)(`useFocus`, hasPointerEvents => {
 
       buttonRef.current.focus();
       suspend = false;
-      await act(async () => {
+      await act(() => {
         root.render(<Component />);
       });
       jest.runAllTimers();
diff --git a/packages/react-native-renderer/src/__tests__/ReactFabric-test.internal.js b/packages/react-native-renderer/src/__tests__/ReactFabric-test.internal.js
index c40f0d1aec76f..935edb0335def 100644
--- a/packages/react-native-renderer/src/__tests__/ReactFabric-test.internal.js
+++ b/packages/react-native-renderer/src/__tests__/ReactFabric-test.internal.js
@@ -50,7 +50,7 @@ describe('ReactFabric', () => {
       uiViewClassName: 'RCTView',
     }));
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<View foo="test" />, 1);
     });
     expect(nativeFabricUIManager.createNode).toBeCalled();
@@ -68,13 +68,13 @@ describe('ReactFabric', () => {
 
     nativeFabricUIManager.createNode.mockReturnValue(firstNode);
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<View foo="foo" />, 11);
     });
 
     expect(nativeFabricUIManager.createNode).toHaveBeenCalledTimes(1);
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<View foo="bar" />, 11);
     });
 
@@ -98,7 +98,7 @@ describe('ReactFabric', () => {
       uiViewClassName: 'RCTText',
     }));
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<Text foo="a">1</Text>, 11);
     });
     expect(nativeFabricUIManager.cloneNode).not.toBeCalled();
@@ -109,7 +109,7 @@ describe('ReactFabric', () => {
     ).not.toBeCalled();
 
     // If no properties have changed, we shouldn't call cloneNode.
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<Text foo="a">1</Text>, 11);
     });
     expect(nativeFabricUIManager.cloneNode).not.toBeCalled();
@@ -120,7 +120,7 @@ describe('ReactFabric', () => {
     ).not.toBeCalled();
 
     // Only call cloneNode for the changed property (and not for text).
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<Text foo="b">1</Text>, 11);
     });
     expect(nativeFabricUIManager.cloneNode).not.toBeCalled();
@@ -133,7 +133,7 @@ describe('ReactFabric', () => {
     ).not.toBeCalled();
 
     // Only call cloneNode for the changed text (and no other properties).
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<Text foo="b">2</Text>, 11);
     });
     expect(nativeFabricUIManager.cloneNode).not.toBeCalled();
@@ -148,7 +148,7 @@ describe('ReactFabric', () => {
     ).not.toBeCalled();
 
     // Call cloneNode for both changed text and properties.
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<Text foo="c">3</Text>, 11);
     });
     expect(nativeFabricUIManager.cloneNode).not.toBeCalled();
@@ -169,7 +169,7 @@ describe('ReactFabric', () => {
       uiViewClassName: 'RCTText',
     }));
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <Text foo="a" bar="a">
           1
@@ -184,7 +184,7 @@ describe('ReactFabric', () => {
       nativeFabricUIManager.cloneNodeWithNewChildrenAndProps,
     ).not.toBeCalled();
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <Text foo="a" bar="b">
           1
@@ -201,7 +201,7 @@ describe('ReactFabric', () => {
       nativeFabricUIManager.__dumpHierarchyForJestTestsOnly(),
     ).toMatchSnapshot();
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <Text foo="b" bar="b">
           2
@@ -228,7 +228,7 @@ describe('ReactFabric', () => {
     nativeFabricUIManager.dispatchCommand.mockClear();
 
     let viewRef;
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <View
           ref={ref => {
@@ -259,7 +259,7 @@ describe('ReactFabric', () => {
     nativeFabricUIManager.dispatchCommand.mockReset();
 
     let viewRef;
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <BasicClass
           ref={ref => {
@@ -289,7 +289,7 @@ describe('ReactFabric', () => {
     nativeFabricUIManager.sendAccessibilityEvent.mockClear();
 
     let viewRef;
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <View
           ref={ref => {
@@ -321,7 +321,7 @@ describe('ReactFabric', () => {
     nativeFabricUIManager.sendAccessibilityEvent.mockReset();
 
     let viewRef;
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <BasicClass
           ref={ref => {
@@ -386,14 +386,14 @@ describe('ReactFabric', () => {
     const before = 'abcdefghijklmnopqrst';
     const after = 'mxhpgwfralkeoivcstzy';
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<Component chars={before} />, 11);
     });
     expect(
       nativeFabricUIManager.__dumpHierarchyForJestTestsOnly(),
     ).toMatchSnapshot();
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<Component chars={after} />, 11);
     });
     expect(
@@ -428,7 +428,7 @@ describe('ReactFabric', () => {
 
     const ref = React.createRef();
     // Wrap in a host node.
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <View>
           <Component ref={ref} />
@@ -461,7 +461,7 @@ describe('ReactFabric', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<Component />, 11);
     });
     expect(mockArgs.length).toEqual(0);
@@ -483,7 +483,7 @@ describe('ReactFabric', () => {
       );
     });
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <View foo="a">
           <View foo="b" />
@@ -508,7 +508,7 @@ describe('ReactFabric', () => {
       uiViewClassName: 'RCTView',
     }));
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <Text>
           <View />
@@ -517,7 +517,7 @@ describe('ReactFabric', () => {
       );
     });
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <Text>
           <Image />
@@ -542,13 +542,13 @@ describe('ReactFabric', () => {
     }));
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactFabric.render(<View>this should warn</View>, 11);
       });
     }).toErrorDev(['Text strings must be rendered within a <Text> component.']);
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactFabric.render(
           <Text>
             <ScrollView>hi hello hi</ScrollView>
@@ -567,7 +567,7 @@ describe('ReactFabric', () => {
 
     const Indirection = () => 'Hi';
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <Text>
           <Indirection />
@@ -591,7 +591,7 @@ describe('ReactFabric', () => {
     const touchStart = jest.fn();
     const touchStart2 = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<View onTouchStart={touchStart} />, 11);
     });
 
@@ -617,7 +617,7 @@ describe('ReactFabric', () => {
     expect(touchStart).toBeCalled();
     expect(touchStart2).not.toBeCalled();
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(<View onTouchStart={touchStart2} />, 11);
     });
 
@@ -665,7 +665,7 @@ describe('ReactFabric', () => {
 
       const event = {};
 
-      await act(async () => {
+      await act(() => {
         ReactFabric.render(
           <View
             onSkippedBubblingEventCapture={ancestorCapture}
@@ -752,7 +752,7 @@ describe('ReactFabric', () => {
     const ref1 = React.createRef();
     const ref2 = React.createRef();
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <View id="parent">
           <View
@@ -834,7 +834,7 @@ describe('ReactFabric', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <ContainsStrictModeChild ref={n => (parent = n)} />,
         11,
@@ -871,7 +871,7 @@ describe('ReactFabric', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <StrictMode>
           <IsInStrictMode ref={n => (parent = n)} />
@@ -914,7 +914,7 @@ describe('ReactFabric', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <ContainsStrictModeChild ref={n => (parent = n)} />,
         11,
@@ -949,7 +949,7 @@ describe('ReactFabric', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <StrictMode>
           <IsInStrictMode ref={n => (parent = n)} />
@@ -980,7 +980,7 @@ describe('ReactFabric', () => {
     nativeFabricUIManager.sendAccessibilityEvent.mockReset();
 
     let viewRef;
-    await act(async () => {
+    await act(() => {
       ReactFabric.render(
         <View
           ref={ref => {
@@ -991,7 +991,7 @@ describe('ReactFabric', () => {
       );
     });
     const dangerouslyRetainedViewRef = viewRef;
-    await act(async () => {
+    await act(() => {
       ReactFabric.stopSurface(11);
     });
 
diff --git a/packages/react-native-renderer/src/__tests__/ReactFabricHostComponent-test.internal.js b/packages/react-native-renderer/src/__tests__/ReactFabricHostComponent-test.internal.js
index a4a692967f300..ceab02d8497be 100644
--- a/packages/react-native-renderer/src/__tests__/ReactFabricHostComponent-test.internal.js
+++ b/packages/react-native-renderer/src/__tests__/ReactFabricHostComponent-test.internal.js
@@ -48,7 +48,7 @@ async function mockRenderKeys(keyLists) {
     const keyList = keyLists[i];
     if (Array.isArray(keyList)) {
       const refs = keyList.map(key => undefined);
-      await act(async () => {
+      await act(() => {
         ReactFabric.render(
           <MockView>
             {keyList.map((key, index) => (
@@ -68,7 +68,7 @@ async function mockRenderKeys(keyLists) {
       continue;
     }
     if (keyList == null) {
-      await act(async () => {
+      await act(() => {
         ReactFabric.stopSurface(mockContainerTag);
       });
       result.push(null);
diff --git a/packages/react-reconciler/src/__tests__/ReactCPUSuspense-test.js b/packages/react-reconciler/src/__tests__/ReactCPUSuspense-test.js
index 5be9669d0fe16..d640f87205e45 100644
--- a/packages/react-reconciler/src/__tests__/ReactCPUSuspense-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactCPUSuspense-test.js
@@ -176,7 +176,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
     // Initial mount
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     // Inner contents finish in separate commit from outer
@@ -189,7 +189,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
     );
 
     // Update
-    await act(async () => {
+    await act(() => {
       setCount(1);
     });
     // Entire update finishes in a single commit
@@ -277,7 +277,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     // Each level commits separately
diff --git a/packages/react-reconciler/src/__tests__/ReactCache-test.js b/packages/react-reconciler/src/__tests__/ReactCache-test.js
index a0ba653bfaa83..6b1cb7423a4a9 100644
--- a/packages/react-reconciler/src/__tests__/ReactCache-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactCache-test.js
@@ -185,7 +185,7 @@ describe('ReactCache', () => {
   // @gate enableCacheElement && enableCache
   test('render Cache component', async () => {
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Cache>Hi</Cache>);
     });
     expect(root).toMatchRenderedOutput('Hi');
@@ -194,7 +194,7 @@ describe('ReactCache', () => {
   // @gate enableCacheElement && enableCache
   test('mount new data', async () => {
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Cache>
           <Suspense fallback={<Text text="Loading..." />}>
@@ -206,13 +206,13 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A']);
     expect(root).toMatchRenderedOutput('A');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // no cleanup: cache is still retained at the root
@@ -223,7 +223,7 @@ describe('ReactCache', () => {
   // @gate enableCache
   test('root acts as implicit cache boundary', async () => {
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="Loading..." />}>
           <AsyncText text="A" />
@@ -233,13 +233,13 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A']);
     expect(root).toMatchRenderedOutput('A');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // no cleanup: cache is still retained at the root
@@ -267,7 +267,7 @@ describe('ReactCache', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={false} />);
     });
 
@@ -276,13 +276,13 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...', 'Loading...']);
     expect(root).toMatchRenderedOutput('Loading...Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // no cleanup: cache is still retained at the root
@@ -312,13 +312,13 @@ describe('ReactCache', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={false} />);
     });
     assertLog([]);
     expect(root).toMatchRenderedOutput('(empty)');
 
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={true} />);
     });
     // Even though there are two new <Cache /> trees, they should share the same
@@ -326,13 +326,13 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...', 'Loading...']);
     expect(root).toMatchRenderedOutput('Loading...Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // cleanup occurs for the cache shared by the inner cache boundaries (which
@@ -359,7 +359,7 @@ describe('ReactCache', () => {
       }
 
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(<App />);
       });
       // Even though there is a nested <Cache /> boundary, it should share the same
@@ -367,13 +367,13 @@ describe('ReactCache', () => {
       assertLog(['Cache miss! [A]', 'Loading...']);
       expect(root).toMatchRenderedOutput('Loading...');
 
-      await act(async () => {
+      await act(() => {
         resolveMostRecentTextCache('A');
       });
       assertLog(['A', 'A']);
       expect(root).toMatchRenderedOutput('AA');
 
-      await act(async () => {
+      await act(() => {
         root.render('Bye');
       });
       // no cleanup: cache is still retained at the root
@@ -400,7 +400,7 @@ describe('ReactCache', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       seedNextTextCache('A');
       root.render(<App showMore={false} />);
     });
@@ -408,7 +408,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Add a new cache boundary
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={true} />);
     });
     assertLog([
@@ -418,7 +418,7 @@ describe('ReactCache', () => {
     ]);
     expect(root).toMatchRenderedOutput('A [v1]A [v1]');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // no cleanup: cache is still retained at the root
@@ -448,7 +448,7 @@ describe('ReactCache', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       seedNextTextCache('A');
       root.render(<App showMore={false} />);
     });
@@ -456,7 +456,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Add a new cache boundary
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={true} />);
     });
     assertLog([
@@ -466,7 +466,7 @@ describe('ReactCache', () => {
       'Loading...',
     ]);
     expect(root).toMatchRenderedOutput('A [v1]Loading...');
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v2]']);
@@ -475,7 +475,7 @@ describe('ReactCache', () => {
     // Replace all the children: this should retain the root Cache instance,
     // but cleanup the separate cache instance created for the fresh cache
     // boundary
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     // Cleanup occurs for the *second* cache instance: the first is still
@@ -524,13 +524,13 @@ describe('ReactCache', () => {
       return <Text text="Content" />;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Cache miss! [A]', 'Loading shell...']);
     expect(root).toMatchRenderedOutput('Loading shell...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog([
@@ -547,7 +547,7 @@ describe('ReactCache', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('B');
     });
     assertLog(['Content']);
@@ -558,7 +558,7 @@ describe('ReactCache', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // no cleanup: cache is still retained at the root
@@ -608,19 +608,19 @@ describe('ReactCache', () => {
       return <Text text="Content" />;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={false} />);
     });
     assertLog([]);
     expect(root).toMatchRenderedOutput('(empty)');
 
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={true} />);
     });
     assertLog(['Cache miss! [A]', 'Loading shell...']);
     expect(root).toMatchRenderedOutput('Loading shell...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog([
@@ -637,7 +637,7 @@ describe('ReactCache', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('B');
     });
     assertLog(['Content']);
@@ -648,7 +648,7 @@ describe('ReactCache', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     assertLog(['Cache cleanup: A [v1]', 'Cache cleanup: B [v1]']);
@@ -665,7 +665,7 @@ describe('ReactCache', () => {
 
     // Mount initial data
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="Loading..." />}>
           <App />
@@ -675,20 +675,20 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Refresh for new data.
-    await act(async () => {
+    await act(() => {
       startTransition(() => refresh());
     });
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     // Note that the version has updated
@@ -699,7 +699,7 @@ describe('ReactCache', () => {
     }
     expect(root).toMatchRenderedOutput('A [v2]');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     expect(root).toMatchRenderedOutput('Bye');
@@ -715,7 +715,7 @@ describe('ReactCache', () => {
 
     // Mount initial data
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="Loading..." />}>
           <App />
@@ -725,27 +725,27 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Refresh for new data.
-    await act(async () => {
+    await act(() => {
       startTransition(() => refresh());
     });
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     // Note that the version has updated, and the previous cache is cleared
     assertLog(['A [v2]', 'Cache cleanup: A [v1]']);
     expect(root).toMatchRenderedOutput('A [v2]');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // the original root cache already cleaned up when the refresh completed
@@ -763,7 +763,7 @@ describe('ReactCache', () => {
 
     // Mount initial data
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="Loading..." />}>
           <App />
@@ -773,14 +773,14 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Refresh for new data.
-    await act(async () => {
+    await act(() => {
       refresh();
     });
     assertLog([
@@ -793,14 +793,14 @@ describe('ReactCache', () => {
     ]);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     // Note that the version has updated, and the previous cache is cleared
     assertLog(['A [v2]']);
     expect(root).toMatchRenderedOutput('A [v2]');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // the original root cache already cleaned up when the refresh completed
@@ -827,7 +827,7 @@ describe('ReactCache', () => {
 
     // Mount initial data
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Cache>
           <Suspense fallback={<Text text="Loading..." />}>
@@ -839,14 +839,14 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Refresh for new data.
-    await act(async () => {
+    await act(() => {
       // Refresh the cache with seeded data, like you would receive from a
       // server mutation.
       // TODO: Seeding multiple typed textCaches. Should work by calling `refresh`
@@ -863,7 +863,7 @@ describe('ReactCache', () => {
     assertLog(['A [v2]']);
     expect(root).toMatchRenderedOutput('A [v2]');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye');
     });
     // the refreshed cache boundary is unmounted and cleans up
@@ -898,7 +898,7 @@ describe('ReactCache', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       seedNextTextCache('A');
       root.render(<App showMore={false} />);
     });
@@ -906,7 +906,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Add a new cache boundary
-    await act(async () => {
+    await act(() => {
       seedNextTextCache('A');
       root.render(<App showMore={true} />);
     });
@@ -919,13 +919,13 @@ describe('ReactCache', () => {
 
     // Now refresh the shell. This should also cause the "Show More" contents to
     // refresh, since its cache is nested inside the outer one.
-    await act(async () => {
+    await act(() => {
       startTransition(() => refreshShell());
     });
     assertLog(['Cache miss! [A]', 'Loading...', 'Loading...']);
     expect(root).toMatchRenderedOutput('A [v1]A [v2]');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog([
@@ -937,7 +937,7 @@ describe('ReactCache', () => {
     ]);
     expect(root).toMatchRenderedOutput('A [v3]A [v3]');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     // Unmounting children releases the refreshed cache instance only; the root
@@ -980,12 +980,12 @@ describe('ReactCache', () => {
       // treated like sibling providers that happen to share an underlying
       // cache, as opposed to consumers of the root-level cache.
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(<App showMore={false} />);
       });
 
       // Now reveal the boundaries. In a real app  this would be a navigation.
-      await act(async () => {
+      await act(() => {
         root.render(<App showMore={true} />);
       });
 
@@ -994,7 +994,7 @@ describe('ReactCache', () => {
       assertLog(['Cache miss! [A]', 'Loading...', 'Loading...']);
       expect(root).toMatchRenderedOutput('Loading...Loading...');
 
-      await act(async () => {
+      await act(() => {
         resolveMostRecentTextCache('A');
       });
       assertLog(['A [v1]', 'A [v1]']);
@@ -1007,7 +1007,7 @@ describe('ReactCache', () => {
       });
       assertLog(['Cache miss! [A]', 'Loading...']);
 
-      await act(async () => {
+      await act(() => {
         resolveMostRecentTextCache('A');
       });
       assertLog(['A [v2]']);
@@ -1019,7 +1019,7 @@ describe('ReactCache', () => {
       // a fresh boundary). Therefore this causes cleanup for both the fresh cache
       // instance in the refreshed first boundary and cleanup for the non-refreshed
       // sibling boundary.
-      await act(async () => {
+      await act(() => {
         root.render('Bye!');
       });
       assertLog(['Cache cleanup: A [v2]', 'Cache cleanup: A [v1]']);
@@ -1054,13 +1054,13 @@ describe('ReactCache', () => {
       }
 
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(<App showMore={false} />);
       });
       assertLog(['Cache miss! [A]', 'Cache miss! [B]', 'Loading...']);
       expect(root).toMatchRenderedOutput('Loading...');
 
-      await act(async () => {
+      await act(() => {
         // This will resolve the content in the first cache
         resolveMostRecentTextCache('A');
         resolveMostRecentTextCache('B');
@@ -1079,13 +1079,13 @@ describe('ReactCache', () => {
       expect(root).toMatchRenderedOutput('Loading... A [v1] B [v1]');
 
       // Now resolve the second tree
-      await act(async () => {
+      await act(() => {
         resolveMostRecentTextCache('A');
       });
       assertLog(['A [v2]']);
       expect(root).toMatchRenderedOutput('A [v2] A [v1] B [v1]');
 
-      await act(async () => {
+      await act(() => {
         root.render('Bye!');
       });
       // Unmounting children releases both cache boundaries, but the original
@@ -1107,7 +1107,7 @@ describe('ReactCache', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="Loading..." />}>(empty)</Suspense>,
       );
@@ -1115,7 +1115,7 @@ describe('ReactCache', () => {
     assertLog([]);
     expect(root).toMatchRenderedOutput('(empty)');
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback={<Text text="Loading..." />}>
@@ -1127,7 +1127,7 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('(empty)');
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback={<Text text="Loading..." />}>
@@ -1144,14 +1144,14 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('(empty)');
 
     // Resolve the request
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]', 'A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]A [v1]');
 
     // Now do another transition
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback={<Text text="Loading..." />}>
@@ -1172,7 +1172,7 @@ describe('ReactCache', () => {
     ]);
     expect(root).toMatchRenderedOutput('A [v1]A [v1]');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]', 'A [v1]', 'A [v2]']);
@@ -1182,7 +1182,7 @@ describe('ReactCache', () => {
     // commits, so both fresh cache instances are released by their cache boundaries,
     // cleaning up v1 (used for the first two children which render together) and
     // v2 (used for the third boundary added later).
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     assertLog(['Cache cleanup: A [v1]', 'Cache cleanup: A [v2]']);
@@ -1225,13 +1225,13 @@ describe('ReactCache', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['0']);
     expect(root).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         showMore();
       });
@@ -1239,7 +1239,7 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]', 'Loading...']);
     expect(root).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       updateUnrelated(1);
     });
     assertLog([
@@ -1251,7 +1251,7 @@ describe('ReactCache', () => {
     ]);
     expect(root).toMatchRenderedOutput('1');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]']);
@@ -1261,7 +1261,7 @@ describe('ReactCache', () => {
     // render after calling showMore(). This instance is cleaned up when that boundary
     // is unmounted. Bc root cache instance is never accessed, the inner cache
     // boundary ends up at v1.
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     assertLog(['Cache cleanup: A [v1]']);
@@ -1272,7 +1272,7 @@ describe('ReactCache', () => {
   test('cache boundary uses a fresh cache when its key changes', async () => {
     const root = ReactNoop.createRoot();
     seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Cache key="A">
@@ -1285,7 +1285,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('A [v1]');
 
     seedNextTextCache('B');
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Cache key="B">
@@ -1300,7 +1300,7 @@ describe('ReactCache', () => {
     // Unmount children: the fresh cache instance for B cleans up since the cache boundary
     // is the only owner, while the original cache instance (for A) is still retained by
     // the root.
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     assertLog(['Cache cleanup: B [v2]']);
@@ -1310,7 +1310,7 @@ describe('ReactCache', () => {
   // @gate enableCacheElement && enableCache
   test('overlapping transitions after an initial mount use the same fresh cache', async () => {
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Cache key="A">
@@ -1322,14 +1322,14 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // After a mount, subsequent transitions use a fresh cache
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback="Loading...">
@@ -1346,7 +1346,7 @@ describe('ReactCache', () => {
     // Update to a different text and with a different key for the cache
     // boundary: this should still use the fresh cache instance created
     // for the earlier transition
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback="Loading...">
@@ -1360,7 +1360,7 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [C]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('C');
     });
     assertLog(['C [v2]']);
@@ -1368,7 +1368,7 @@ describe('ReactCache', () => {
 
     // Unmount children: the fresh cache used for the updates is freed, while the
     // original cache (with A) is still retained at the root.
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     assertLog(['Cache cleanup: B [v2]', 'Cache cleanup: C [v2]']);
@@ -1378,7 +1378,7 @@ describe('ReactCache', () => {
   // @gate enableCacheElement && enableCache
   test('overlapping updates after an initial mount use the same fresh cache', async () => {
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Cache key="A">
@@ -1390,14 +1390,14 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('A');
     });
     assertLog(['A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // After a mount, subsequent updates use a fresh cache
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Cache key="B">
@@ -1411,7 +1411,7 @@ describe('ReactCache', () => {
 
     // A second update uses the same fresh cache: even though this is a new
     // Cache boundary, the render uses the fresh cache from the pending update.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Cache key="C">
@@ -1423,7 +1423,7 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [C]']);
     expect(root).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       resolveMostRecentTextCache('C');
     });
     assertLog(['C [v2]']);
@@ -1431,7 +1431,7 @@ describe('ReactCache', () => {
 
     // Unmount children: the fresh cache used for the updates is freed, while the
     // original cache (with A) is still retained at the root.
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     assertLog(['Cache cleanup: B [v2]', 'Cache cleanup: C [v2]']);
@@ -1442,7 +1442,7 @@ describe('ReactCache', () => {
   test('cleans up cache only used in an aborted transition', async () => {
     const root = ReactNoop.createRoot();
     seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Cache key="A">
@@ -1456,7 +1456,7 @@ describe('ReactCache', () => {
 
     // Start a transition from A -> B..., which should create a fresh cache
     // for the new cache boundary (bc of the different key)
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback="Loading...">
@@ -1471,7 +1471,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // ...but cancel by transitioning "back" to A (which we never really left)
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback="Loading...">
@@ -1486,7 +1486,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Unmount children: ...
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     assertLog([]);
@@ -1502,7 +1502,7 @@ describe('ReactCache', () => {
       return <AsyncText showVersion={true} text={text} />;
     }
     seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Example text="A" />
@@ -1512,7 +1512,7 @@ describe('ReactCache', () => {
     assertLog(['A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         refresh();
       });
@@ -1520,7 +1520,7 @@ describe('ReactCache', () => {
     assertLog(['Cache miss! [A]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     assertLog([
@@ -1544,7 +1544,7 @@ describe('ReactCache', () => {
       return <AsyncText showVersion={true} text={text} />;
     }
     seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Cache>
@@ -1556,7 +1556,7 @@ describe('ReactCache', () => {
     assertLog(['A [v1]']);
     expect(root).toMatchRenderedOutput('A [v1]');
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         refresh();
       });
@@ -1565,7 +1565,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('A [v1]');
 
     // Unmount the boundary before the refresh can complete
-    await act(async () => {
+    await act(() => {
       root.render('Bye!');
     });
     assertLog([
@@ -1594,14 +1594,14 @@ describe('ReactCache', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App prerenderMore={false} />);
     });
     assertLog([]);
     expect(root).toMatchRenderedOutput(<div hidden={true} />);
 
     seedNextTextCache('More');
-    await act(async () => {
+    await act(() => {
       root.render(<App prerenderMore={true} />);
     });
     assertLog(['More']);
@@ -1629,7 +1629,7 @@ describe('ReactCache', () => {
     function MoreArgs({a, b}) {
       return (types(a) === types(a, b)).toString() + ' ';
     }
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Print a="e" b="f" />
@@ -1641,7 +1641,7 @@ describe('ReactCache', () => {
       );
     });
     expect(root).toMatchRenderedOutput('string string true false false false ');
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Print a="e" b={null} />
@@ -1654,7 +1654,7 @@ describe('ReactCache', () => {
     });
     expect(root).toMatchRenderedOutput('string object true false false false ');
     const obj = {};
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Print a="e" b={obj} />
@@ -1667,7 +1667,7 @@ describe('ReactCache', () => {
     });
     expect(root).toMatchRenderedOutput('string object true false false false ');
     const sameObj = {};
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Print a={sameObj} b={sameObj} />
@@ -1681,7 +1681,7 @@ describe('ReactCache', () => {
     expect(root).toMatchRenderedOutput('object object true true false false ');
     const objA = {};
     const objB = {};
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Print a={objA} b={objB} />
@@ -1694,7 +1694,7 @@ describe('ReactCache', () => {
     });
     expect(root).toMatchRenderedOutput('object object true false false false ');
     const sameSymbol = Symbol();
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Print a={sameSymbol} b={sameSymbol} />
@@ -1707,7 +1707,7 @@ describe('ReactCache', () => {
     });
     expect(root).toMatchRenderedOutput('symbol symbol true true false false ');
     const notANumber = +'nan';
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Print a={1} b={notANumber} />
@@ -1749,7 +1749,7 @@ describe('ReactCache', () => {
 
       return 'Blank';
     }
-    await act(async () => {
+    await act(() => {
       root.render(<Test />);
     });
     expect(x).toBe(y);
diff --git a/packages/react-reconciler/src/__tests__/ReactClassSetStateCallback-test.js b/packages/react-reconciler/src/__tests__/ReactClassSetStateCallback-test.js
index 257a74b2462ff..e9b25f2ca74dc 100644
--- a/packages/react-reconciler/src/__tests__/ReactClassSetStateCallback-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactClassSetStateCallback-test.js
@@ -33,12 +33,12 @@ describe('ReactClassSetStateCallback', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog([0]);
 
-    await act(async () => {
+    await act(() => {
       if (gate(flags => flags.enableUnifiedSyncLane)) {
         React.startTransition(() => {
           app.setState({step: 1}, () => Scheduler.log('Callback 1'));
diff --git a/packages/react-reconciler/src/__tests__/ReactConcurrentErrorRecovery-test.js b/packages/react-reconciler/src/__tests__/ReactConcurrentErrorRecovery-test.js
index 051efa1cd5c39..e14fc83b2a3be 100644
--- a/packages/react-reconciler/src/__tests__/ReactConcurrentErrorRecovery-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactConcurrentErrorRecovery-test.js
@@ -197,14 +197,14 @@ describe('ReactConcurrentErrorRecovery', () => {
     const root = ReactNoop.createRoot();
     seedNextTextCache('A1');
     seedNextTextCache('B1');
-    await act(async () => {
+    await act(() => {
       root.render(<App step={1} />);
     });
     assertLog(['A1', 'B1']);
     expect(root).toMatchRenderedOutput('A1B1');
 
     // Start a refresh transition
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App step={2} />);
       });
@@ -214,7 +214,7 @@ describe('ReactConcurrentErrorRecovery', () => {
     expect(root).toMatchRenderedOutput('A1B1');
 
     // B fails to load.
-    await act(async () => {
+    await act(() => {
       rejectText('B2', new Error('Oops!'));
     });
 
@@ -238,7 +238,7 @@ describe('ReactConcurrentErrorRecovery', () => {
     expect(root).toMatchRenderedOutput('A1B1');
 
     // A finishes loading.
-    await act(async () => {
+    await act(() => {
       resolveText('A2');
     });
     if (gate(flags => flags.replayFailedUnitOfWorkWithInvokeGuardedCallback)) {
@@ -300,14 +300,14 @@ describe('ReactConcurrentErrorRecovery', () => {
     const root = ReactNoop.createRoot();
     seedNextTextCache('A1');
     seedNextTextCache('B1');
-    await act(async () => {
+    await act(() => {
       root.render(<App step={1} />);
     });
     assertLog(['A1', 'B1']);
     expect(root).toMatchRenderedOutput('A1B1');
 
     // Start a refresh transition
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App step={2} />);
       });
@@ -317,7 +317,7 @@ describe('ReactConcurrentErrorRecovery', () => {
     expect(root).toMatchRenderedOutput('A1B1');
 
     // A fails to load.
-    await act(async () => {
+    await act(() => {
       rejectText('A2', new Error('Oops!'));
     });
 
@@ -341,7 +341,7 @@ describe('ReactConcurrentErrorRecovery', () => {
     expect(root).toMatchRenderedOutput('A1B1');
 
     // B finishes loading.
-    await act(async () => {
+    await act(() => {
       resolveText('B2');
     });
     if (gate(flags => flags.replayFailedUnitOfWorkWithInvokeGuardedCallback)) {
@@ -385,7 +385,7 @@ describe('ReactConcurrentErrorRecovery', () => {
     // The initial render suspends without a Suspense boundary. Since it's
     // wrapped in startTransition, it suspends instead of erroring.
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<AsyncText text="Async" />);
       });
@@ -397,7 +397,7 @@ describe('ReactConcurrentErrorRecovery', () => {
     // boundary. (This is only interesting because when a component suspends
     // outside of a transition, we throw an error, which can be captured by
     // an error boundary.
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <ErrorBoundary>
@@ -410,7 +410,7 @@ describe('ReactConcurrentErrorRecovery', () => {
     expect(root).toMatchRenderedOutput(null);
 
     // Continues rendering once data resolves
-    await act(async () => {
+    await act(() => {
       resolveText('Async');
     });
     assertLog(['Async']);
@@ -447,7 +447,7 @@ describe('ReactConcurrentErrorRecovery', () => {
 
       // Suspend and throw in the same transition
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           root.render(
             <ErrorBoundary>
@@ -468,7 +468,7 @@ describe('ReactConcurrentErrorRecovery', () => {
       expect(root).toMatchRenderedOutput(null);
 
       // Try the reverse order, too: throw then suspend
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           root.render(
             <ErrorBoundary>
diff --git a/packages/react-reconciler/src/__tests__/ReactContextPropagation-test.js b/packages/react-reconciler/src/__tests__/ReactContextPropagation-test.js
index e00f4f6c98098..4ddcffea42c2d 100644
--- a/packages/react-reconciler/src/__tests__/ReactContextPropagation-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactContextPropagation-test.js
@@ -203,13 +203,13 @@ describe('ReactLazyContextPropagation', () => {
         return <Text text={value} />;
       }
 
-      await act(async () => {
+      await act(() => {
         root.render(<App />);
       });
       assertLog([0]);
       expect(root).toMatchRenderedOutput('0');
 
-      await act(async () => {
+      await act(() => {
         setValue(1);
       });
       assertLog([1]);
@@ -245,13 +245,13 @@ describe('ReactLazyContextPropagation', () => {
       return <Text text={value} />;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog([0]);
     expect(root).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       setValue(1);
     });
     assertLog([1]);
@@ -288,13 +288,13 @@ describe('ReactLazyContextPropagation', () => {
       return <Text text={value} />;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog([0]);
     expect(root).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       setValue(1);
     });
     assertLog([1]);
@@ -326,13 +326,13 @@ describe('ReactLazyContextPropagation', () => {
       return <Text text={value} />;
     });
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Consumer', 0]);
     expect(root).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       // Intentionally calling setState to some other arbitrary value before
       // setting it back to the current one. That way an update is scheduled,
       // but we'll bail out during render when nothing has changed.
@@ -388,13 +388,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     await seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       // Intentionally not wrapping in startTransition, so that the fallback
       // the fallback displays despite this being a refresh.
       setContext('B');
@@ -468,13 +468,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     await seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A', 'A']);
     expect(root).toMatchRenderedOutput('AAA');
 
-    await act(async () => {
+    await act(() => {
       // Intentionally not wrapping in startTransition, so that the fallback
       // the fallback displays despite this being a refresh.
       setContext('B');
@@ -529,13 +529,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     await seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       // Intentionally not wrapping in startTransition, so that the fallback
       // the fallback displays despite this being a refresh.
       setContext('B');
@@ -583,13 +583,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     await seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       setContext('B');
     });
     assertLog(['B', 'B']);
@@ -644,13 +644,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     await seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A', 'A']);
     expect(root).toMatchRenderedOutput('AAA');
 
-    await act(async () => {
+    await act(() => {
       setContext('B');
     });
     assertLog(['B', 'B', 'B']);
@@ -686,13 +686,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       setContext('B');
     });
     assertLog(['B', 'B']);
@@ -740,13 +740,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       setContext('B');
     });
     assertLog(['B', 'B']);
@@ -803,13 +803,13 @@ describe('ReactLazyContextPropagation', () => {
 
     const root = ReactNoop.createRoot();
     await seedNextTextCache('A');
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       setContext('B');
     });
     assertLog(['Suspend! [B]', 'Loading...']);
@@ -864,13 +864,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       setContext('B');
     });
     assertLog(['B', 'B']);
@@ -913,13 +913,13 @@ describe('ReactLazyContextPropagation', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A', 'A']);
     expect(root).toMatchRenderedOutput('AA');
 
-    await act(async () => {
+    await act(() => {
       setContext('B');
     });
     assertLog(['B', 'B']);
diff --git a/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js b/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
index 4787410a10ac7..54f4ad42f44bc 100644
--- a/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactDeferredValue-test.js
@@ -68,7 +68,7 @@ describe('ReactDeferredValue', () => {
     const root = ReactNoop.createRoot();
 
     // Initial render
-    await act(async () => {
+    await act(() => {
       root.render(<App value={1} />);
     });
     assertLog(['Original: 1', 'Deferred: 1']);
@@ -129,7 +129,7 @@ describe('ReactDeferredValue', () => {
     const root = ReactNoop.createRoot();
 
     // Initial render
-    await act(async () => {
+    await act(() => {
       root.render(<App value={1} />);
     });
     assertLog(['Original: 1', 'Deferred: 1']);
@@ -195,7 +195,7 @@ describe('ReactDeferredValue', () => {
     const root = ReactNoop.createRoot();
 
     // Initial render
-    await act(async () => {
+    await act(() => {
       root.render(<App value={1} />);
     });
     assertLog(['Original: 1', 'Deferred: 1']);
diff --git a/packages/react-reconciler/src/__tests__/ReactEffectOrdering-test.js b/packages/react-reconciler/src/__tests__/ReactEffectOrdering-test.js
index d9cd4bfb48b6e..259492f294cfc 100644
--- a/packages/react-reconciler/src/__tests__/ReactEffectOrdering-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactEffectOrdering-test.js
@@ -53,11 +53,11 @@ describe('ReactEffectOrdering', () => {
       return 'Child';
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Parent />);
     });
     expect(root).toMatchRenderedOutput('Child');
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
     assertLog(['Unmount parent', 'Unmount child']);
@@ -80,11 +80,11 @@ describe('ReactEffectOrdering', () => {
       return 'Child';
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Parent />);
     });
     expect(root).toMatchRenderedOutput('Child');
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
     assertLog(['Unmount parent', 'Unmount child']);
diff --git a/packages/react-reconciler/src/__tests__/ReactExpiration-test.js b/packages/react-reconciler/src/__tests__/ReactExpiration-test.js
index 61146e208feee..e1a8d08bcc7cd 100644
--- a/packages/react-reconciler/src/__tests__/ReactExpiration-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactExpiration-test.js
@@ -456,7 +456,7 @@ describe('ReactExpiration', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Sync pri: 0', 'Normal pri: 0']);
@@ -527,7 +527,7 @@ describe('ReactExpiration', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Sync pri: 0', 'Idle pri: 0']);
@@ -590,7 +590,7 @@ describe('ReactExpiration', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A0', 'B0', 'C']);
@@ -682,7 +682,7 @@ describe('ReactExpiration', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A0', 'B0']);
@@ -723,13 +723,13 @@ describe('ReactExpiration', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App step={0} />);
     });
     assertLog(['A0', 'B0', 'C0', 'Effect: 0']);
     expect(root).toMatchRenderedOutput('A0B0C0');
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App step={1} />);
       });
diff --git a/packages/react-reconciler/src/__tests__/ReactFlushSync-test.js b/packages/react-reconciler/src/__tests__/ReactFlushSync-test.js
index 7b017aa9b858c..6ed8d95013947 100644
--- a/packages/react-reconciler/src/__tests__/ReactFlushSync-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactFlushSync-test.js
@@ -95,13 +95,13 @@ describe('ReactFlushSync', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['0, 0']);
     expect(root).toMatchRenderedOutput('0, 0');
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.flushSync(() => {
         startTransition(() => {
           // This should be async even though flushSync is on the stack, because
@@ -132,7 +132,7 @@ describe('ReactFlushSync', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       ReactNoop.flushSync(() => {
         root.render(<App />);
       });
@@ -155,7 +155,7 @@ describe('ReactFlushSync', () => {
     }
 
     const root = ReactNoop.createLegacyRoot();
-    await act(async () => {
+    await act(() => {
       ReactNoop.flushSync(() => {
         root.render(<App />);
       });
@@ -182,7 +182,7 @@ describe('ReactFlushSync', () => {
     }
 
     const root = ReactNoop.createLegacyRoot();
-    await act(async () => {
+    await act(() => {
       ReactNoop.flushSync(() => {
         root.render(<App step={1} />);
       });
diff --git a/packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js b/packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js
index 743a58711a8b4..dbcc76333486b 100644
--- a/packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactHooks-test.internal.js
@@ -92,7 +92,7 @@ describe('ReactHooks', () => {
     expect(root).toMatchRenderedOutput('0, 0');
 
     // Normal update
-    await act(async () => {
+    await act(() => {
       setCounter1(1);
       setCounter2(1);
     });
@@ -100,12 +100,12 @@ describe('ReactHooks', () => {
     assertLog(['Parent: 1, 1', 'Child: 1, 1', 'Effect: 1, 1']);
 
     // Update that bails out.
-    await act(async () => setCounter1(1));
+    await act(() => setCounter1(1));
     assertLog(['Parent: 1, 1']);
 
     // This time, one of the state updates but the other one doesn't. So we
     // can't bail out.
-    await act(async () => {
+    await act(() => {
       setCounter1(1);
       setCounter2(2);
     });
@@ -113,7 +113,7 @@ describe('ReactHooks', () => {
     assertLog(['Parent: 1, 2', 'Child: 1, 2', 'Effect: 1, 2']);
 
     // Lots of updates that eventually resolve to the current values.
-    await act(async () => {
+    await act(() => {
       setCounter1(9);
       setCounter2(3);
       setCounter1(4);
@@ -127,7 +127,7 @@ describe('ReactHooks', () => {
     assertLog(['Parent: 1, 2']);
 
     // prepare to check SameValue
-    await act(async () => {
+    await act(() => {
       setCounter1(0 / -1);
       setCounter2(NaN);
     });
@@ -135,7 +135,7 @@ describe('ReactHooks', () => {
     assertLog(['Parent: 0, NaN', 'Child: 0, NaN', 'Effect: 0, NaN']);
 
     // check if re-setting to negative 0 / NaN still bails out
-    await act(async () => {
+    await act(() => {
       setCounter1(0 / -1);
       setCounter2(NaN);
       setCounter2(Infinity);
@@ -145,7 +145,7 @@ describe('ReactHooks', () => {
     assertLog(['Parent: 0, NaN']);
 
     // check if changing negative 0 to positive 0 does not bail out
-    await act(async () => {
+    await act(() => {
       setCounter1(0);
     });
     assertLog(['Parent: 0, NaN', 'Child: 0, NaN', 'Effect: 0, NaN']);
@@ -180,7 +180,7 @@ describe('ReactHooks', () => {
     expect(root).toMatchRenderedOutput('0, 0 (light)');
 
     // Normal update
-    await act(async () => {
+    await act(() => {
       setCounter1(1);
       setCounter2(1);
     });
@@ -188,12 +188,12 @@ describe('ReactHooks', () => {
     assertLog(['Parent: 1, 1 (light)', 'Child: 1, 1 (light)']);
 
     // Update that bails out.
-    await act(async () => setCounter1(1));
+    await act(() => setCounter1(1));
     assertLog(['Parent: 1, 1 (light)']);
 
     // This time, one of the state updates but the other one doesn't. So we
     // can't bail out.
-    await act(async () => {
+    await act(() => {
       setCounter1(1);
       setCounter2(2);
     });
@@ -202,7 +202,7 @@ describe('ReactHooks', () => {
 
     // Updates bail out, but component still renders because props
     // have changed
-    await act(async () => {
+    await act(() => {
       setCounter1(1);
       setCounter2(2);
       root.update(<Parent theme="dark" />);
@@ -211,7 +211,7 @@ describe('ReactHooks', () => {
     assertLog(['Parent: 1, 2 (dark)', 'Child: 1, 2 (dark)']);
 
     // Both props and state bail out
-    await act(async () => {
+    await act(() => {
       setCounter1(1);
       setCounter2(2);
       root.update(<Parent theme="dark" />);
@@ -238,7 +238,7 @@ describe('ReactHooks', () => {
     expect(root).toMatchRenderedOutput('0');
 
     await expect(async () => {
-      await act(async () =>
+      await act(() =>
         setCounter(1, () => {
           throw new Error('Expected to ignore the callback.');
         }),
@@ -272,7 +272,7 @@ describe('ReactHooks', () => {
     expect(root).toMatchRenderedOutput('0');
 
     await expect(async () => {
-      await act(async () =>
+      await act(() =>
         dispatch(1, () => {
           throw new Error('Expected to ignore the callback.');
         }),
@@ -323,7 +323,7 @@ describe('ReactHooks', () => {
       return <Child text={text} />;
     }
     const root = ReactTestRenderer.create(null, {unstable_isConcurrent: true});
-    await act(async () => {
+    await act(() => {
       root.update(
         <ThemeProvider>
           <Parent />
@@ -346,18 +346,18 @@ describe('ReactHooks', () => {
     expect(root).toMatchRenderedOutput('0 (light)');
 
     // Normal update
-    await act(async () => setCounter(1));
+    await act(() => setCounter(1));
     assertLog(['Parent: 1 (light)', 'Child: 1 (light)', 'Effect: 1 (light)']);
     expect(root).toMatchRenderedOutput('1 (light)');
 
     // Update that doesn't change state, so it bails out
-    await act(async () => setCounter(1));
+    await act(() => setCounter(1));
     assertLog(['Parent: 1 (light)']);
     expect(root).toMatchRenderedOutput('1 (light)');
 
     // Update that doesn't change state, but the context changes, too, so it
     // can't bail out
-    await act(async () => {
+    await act(() => {
       setCounter(1);
       setTheme('dark');
     });
@@ -396,7 +396,7 @@ describe('ReactHooks', () => {
     expect(root).toMatchRenderedOutput('0');
 
     // Normal update
-    await act(async () => setCounter(1));
+    await act(() => setCounter(1));
     assertLog(['Parent: 1', 'Child: 1', 'Effect: 1']);
     expect(root).toMatchRenderedOutput('1');
 
@@ -404,30 +404,30 @@ describe('ReactHooks', () => {
     // because the alternate fiber has pending update priority, so we have to
     // enter the render phase before we can bail out. But we bail out before
     // rendering the child, and we don't fire any effects.
-    await act(async () => setCounter(1));
+    await act(() => setCounter(1));
     assertLog(['Parent: 1']);
     expect(root).toMatchRenderedOutput('1');
 
     // Update to the same state again. This times, neither fiber has pending
     // update priority, so we can bail out before even entering the render phase.
-    await act(async () => setCounter(1));
+    await act(() => setCounter(1));
     await waitForAll([]);
     expect(root).toMatchRenderedOutput('1');
 
     // This changes the state to something different so it renders normally.
-    await act(async () => setCounter(2));
+    await act(() => setCounter(2));
     assertLog(['Parent: 2', 'Child: 2', 'Effect: 2']);
     expect(root).toMatchRenderedOutput('2');
 
     // prepare to check SameValue
-    await act(async () => {
+    await act(() => {
       setCounter(0);
     });
     assertLog(['Parent: 0', 'Child: 0', 'Effect: 0']);
     expect(root).toMatchRenderedOutput('0');
 
     // Update to the same state for the first time to flush the queue
-    await act(async () => {
+    await act(() => {
       setCounter(0);
     });
 
@@ -435,14 +435,14 @@ describe('ReactHooks', () => {
     expect(root).toMatchRenderedOutput('0');
 
     // Update again to the same state. Should bail out.
-    await act(async () => {
+    await act(() => {
       setCounter(0);
     });
     await waitForAll([]);
     expect(root).toMatchRenderedOutput('0');
 
     // Update to a different state (positive 0 to negative 0)
-    await act(async () => {
+    await act(() => {
       setCounter(0 / -1);
     });
     assertLog(['Parent: 0', 'Child: 0', 'Effect: 0']);
@@ -629,7 +629,7 @@ describe('ReactHooks', () => {
     }
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactTestRenderer.create(<App deps={'hello'} />);
       });
     }).toErrorDev([
@@ -643,7 +643,7 @@ describe('ReactHooks', () => {
         'When specified, the final argument must be an array.',
     ]);
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactTestRenderer.create(<App deps={100500} />);
       });
     }).toErrorDev([
@@ -657,7 +657,7 @@ describe('ReactHooks', () => {
         'When specified, the final argument must be an array.',
     ]);
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactTestRenderer.create(<App deps={{}} />);
       });
     }).toErrorDev([
@@ -671,7 +671,7 @@ describe('ReactHooks', () => {
         'When specified, the final argument must be an array.',
     ]);
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<App deps={[]} />);
       ReactTestRenderer.create(<App deps={null} />);
       ReactTestRenderer.create(<App deps={undefined} />);
@@ -714,7 +714,7 @@ describe('ReactHooks', () => {
     }
 
     const root = ReactTestRenderer.create(null);
-    await act(async () => {
+    await act(() => {
       root.update(<Counter />);
     });
     expect(root).toMatchRenderedOutput('4');
@@ -738,7 +738,7 @@ describe('ReactHooks', () => {
     }
 
     const root = ReactTestRenderer.create(null);
-    await act(async () => {
+    await act(() => {
       root.update(<Counter />);
     });
     expect(root).toMatchRenderedOutput('4');
@@ -761,7 +761,7 @@ describe('ReactHooks', () => {
     }
 
     const root = ReactTestRenderer.create(null);
-    await act(async () => {
+    await act(() => {
       root.update(<Counter />);
     });
     expect(root).toMatchRenderedOutput('4');
@@ -1131,7 +1131,7 @@ describe('ReactHooks', () => {
     }
     // Verify it doesn't think we're still inside a Hook.
     // Should have no warnings.
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<Valid />);
     });
 
@@ -1488,12 +1488,12 @@ describe('ReactHooks', () => {
           /* eslint-enable no-unused-vars */
         }
         let root;
-        await act(async () => {
+        await act(() => {
           root = ReactTestRenderer.create(<App update={false} />);
         });
         await expect(async () => {
           try {
-            await act(async () => {
+            await act(() => {
               root.update(<App update={true} />);
             });
           } catch (error) {
@@ -1514,7 +1514,7 @@ describe('ReactHooks', () => {
 
         // further warnings for this component are silenced
         try {
-          await act(async () => {
+          await act(() => {
             root.update(<App update={false} />);
           });
         } catch (error) {
@@ -1537,13 +1537,13 @@ describe('ReactHooks', () => {
           /* eslint-enable no-unused-vars */
         }
         let root;
-        await act(async () => {
+        await act(() => {
           root = ReactTestRenderer.create(<App update={false} />);
         });
 
         await expect(async () => {
           try {
-            await act(async () => {
+            await act(() => {
               root.update(<App update={true} />);
             });
           } catch (error) {
@@ -1591,11 +1591,11 @@ describe('ReactHooks', () => {
           /* eslint-enable no-unused-vars */
         }
         let root;
-        await act(async () => {
+        await act(() => {
           root = ReactTestRenderer.create(<App update={false} />);
         });
 
-        await act(async () => {
+        await act(() => {
           expect(() => {
             root.update(<App update={true} />);
           }).toThrow('Rendered fewer hooks than expected. ');
@@ -1703,7 +1703,7 @@ describe('ReactHooks', () => {
       return null;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.unstable_batchedUpdates(() => {
         ReactTestRenderer.create(
           <>
@@ -1761,7 +1761,7 @@ describe('ReactHooks', () => {
       return null;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<A />);
     });
 
@@ -1911,7 +1911,7 @@ describe('ReactHooks', () => {
     }
 
     let root;
-    await act(async () => {
+    await act(() => {
       root = ReactTestRenderer.create(
         <ErrorBoundary>
           <Thrower />
@@ -1920,7 +1920,7 @@ describe('ReactHooks', () => {
     });
 
     expect(root).toMatchRenderedOutput('Throw!');
-    await act(async () => setShouldThrow(true));
+    await act(() => setShouldThrow(true));
     expect(root).toMatchRenderedOutput('Error!');
   });
 });
diff --git a/packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.js b/packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.js
index dba27054bba81..e7dd2a2eef6b8 100644
--- a/packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactHooksWithNoopRenderer-test.js
@@ -294,11 +294,11 @@ describe('ReactHooksWithNoopRenderer', () => {
       await waitForAll(['Count: 0']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 0" />);
 
-      await act(async () => counter.current.updateCount(1));
+      await act(() => counter.current.updateCount(1));
       assertLog(['Count: 1']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 1" />);
 
-      await act(async () => counter.current.updateCount(count => count + 10));
+      await act(() => counter.current.updateCount(count => count + 10));
       assertLog(['Count: 11']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 11" />);
     });
@@ -318,7 +318,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       await waitForAll(['getInitialState', 'Count: 42']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 42" />);
 
-      await act(async () => counter.current.updateCount(7));
+      await act(() => counter.current.updateCount(7));
       assertLog(['Count: 7']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 7" />);
     });
@@ -336,10 +336,10 @@ describe('ReactHooksWithNoopRenderer', () => {
       await waitForAll(['Count: 0']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 0" />);
 
-      await act(async () => counter.current.updateCount(7));
+      await act(() => counter.current.updateCount(7));
       assertLog(['Count: 7']);
 
-      await act(async () => counter.current.updateLabel('Total'));
+      await act(() => counter.current.updateLabel('Total'));
       assertLog(['Total: 7']);
     });
 
@@ -356,13 +356,13 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const firstUpdater = updater;
 
-      await act(async () => firstUpdater(1));
+      await act(() => firstUpdater(1));
       assertLog(['Count: 1']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 1" />);
 
       const secondUpdater = updater;
 
-      await act(async () => firstUpdater(count => count + 10));
+      await act(() => firstUpdater(count => count + 10));
       assertLog(['Count: 11']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 11" />);
 
@@ -381,7 +381,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       await waitForAll([]);
       ReactNoop.render(null);
       await waitForAll([]);
-      await act(async () => _updateCount(1));
+      await act(() => _updateCount(1));
     });
 
     it('works with memo', async () => {
@@ -401,7 +401,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       await waitForAll([]);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 0" />);
 
-      await act(async () => _updateCount(1));
+      await act(() => _updateCount(1));
       assertLog(['Count: 1']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 1" />);
     });
@@ -476,7 +476,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root = ReactNoop.createRoot();
 
-      await act(async () => {
+      await act(() => {
         root.render(
           <>
             <Foo />
@@ -637,7 +637,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       // Test that it works on update, too. This time the log is a bit different
       // because we started with reducerB instead of reducerA.
-      await act(async () => {
+      await act(() => {
         counter.current.dispatch('reset');
       });
       ReactNoop.render(<Counter ref={counter} />);
@@ -785,13 +785,13 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root = ReactNoop.createRoot();
 
-      await act(async () => {
+      await act(() => {
         root.render(<ScrollView row={10} />);
       });
       assertLog(['Up']);
       expect(root).toMatchRenderedOutput(<span prop="Up" />);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.discreteUpdates(() => {
           setRow(5);
         });
@@ -851,10 +851,10 @@ describe('ReactHooksWithNoopRenderer', () => {
       await waitForAll(['Count: 0']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 0" />);
 
-      await act(async () => counter.current.dispatch(INCREMENT));
+      await act(() => counter.current.dispatch(INCREMENT));
       assertLog(['Count: 1']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 1" />);
-      await act(async () => {
+      await act(() => {
         counter.current.dispatch(DECREMENT);
         counter.current.dispatch(DECREMENT);
         counter.current.dispatch(DECREMENT);
@@ -893,11 +893,11 @@ describe('ReactHooksWithNoopRenderer', () => {
       await waitForAll(['Init', 'Count: 10']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 10" />);
 
-      await act(async () => counter.current.dispatch(INCREMENT));
+      await act(() => counter.current.dispatch(INCREMENT));
       assertLog(['Count: 11']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 11" />);
 
-      await act(async () => {
+      await act(() => {
         counter.current.dispatch(DECREMENT);
         counter.current.dispatch(DECREMENT);
         counter.current.dispatch(DECREMENT);
@@ -1427,7 +1427,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         return state;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderToRootWithID(<Component />, 'root', () =>
           Scheduler.log('Sync effect'),
         );
@@ -1437,7 +1437,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       ReactNoop.unmountRootWithID('root');
       await waitForAll(['passive destroy']);
 
-      await act(async () => {
+      await act(() => {
         updaterFunction(true);
       });
     });
@@ -1624,7 +1624,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 0" />);
       // A flush sync doesn't cause the passive effects to fire.
       // So we haven't added the other update yet.
-      await act(async () => {
+      await act(() => {
         ReactNoop.flushSync(() => {
           _updateCount(2);
         });
@@ -1660,7 +1660,7 @@ describe('ReactHooksWithNoopRenderer', () => {
           }, [props.count]);
           return <Text text={'Count: ' + count} />;
         }
-        await act(async () => {
+        await act(() => {
           ReactNoop.flushSync(() => {
             ReactNoop.renderLegacySyncRoot(<Counter count={0} />);
           });
@@ -2256,7 +2256,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       // @gate skipUnmountedBoundaries
       it('should use the nearest still-mounted boundary if there are no unmounted boundaries', async () => {
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <LogOnlyErrorBoundary>
               <BrokenUseEffectCleanup />
@@ -2269,7 +2269,7 @@ describe('ReactHooksWithNoopRenderer', () => {
           'BrokenUseEffectCleanup useEffect',
         ]);
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(<LogOnlyErrorBoundary />);
         });
 
@@ -2294,7 +2294,7 @@ describe('ReactHooksWithNoopRenderer', () => {
           }
         }
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <LogOnlyErrorBoundary>
               <Conditional showChildren={true} />
@@ -2308,7 +2308,7 @@ describe('ReactHooksWithNoopRenderer', () => {
           'BrokenUseEffectCleanup useEffect',
         ]);
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <LogOnlyErrorBoundary>
               <Conditional showChildren={false} />
@@ -2333,7 +2333,7 @@ describe('ReactHooksWithNoopRenderer', () => {
           }
         }
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary>
               <Conditional showChildren={true} />
@@ -2346,7 +2346,7 @@ describe('ReactHooksWithNoopRenderer', () => {
           'BrokenUseEffectCleanup useEffect',
         ]);
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary>
               <Conditional showChildren={false} />
@@ -2381,7 +2381,7 @@ describe('ReactHooksWithNoopRenderer', () => {
           }
         }
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(<Conditional showChildren={true} />);
         });
 
@@ -2424,7 +2424,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         prevProps.prop === nextProps.prop;
       const MemoizedChild = React.memo(Child, isEqual);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <Wrapper>
             <MemoizedChild key={1} />
@@ -2434,7 +2434,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       assertLog(['render', 'layout create', 'passive create']);
 
       // Include at least one no-op (memoized) update to trigger original bug.
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <Wrapper>
             <MemoizedChild key={1} />
@@ -2443,7 +2443,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       });
       assertLog([]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <Wrapper>
             <MemoizedChild key={2} />
@@ -2458,7 +2458,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         'passive create',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog(['layout destroy', 'passive destroy']);
@@ -2491,7 +2491,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         prevProps.prop === nextProps.prop;
       const MemoizedChild = React.memo(Child, isEqual);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <Wrapper>
             <MemoizedChild key={1} />
@@ -2501,7 +2501,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       assertLog(['render', 'layout create', 'passive create']);
 
       // Include at least one no-op (memoized) update to trigger original bug.
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <Wrapper>
             <MemoizedChild key={1} />
@@ -2510,7 +2510,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       });
       assertLog([]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <Wrapper>
             <MemoizedChild key={2} />
@@ -2525,7 +2525,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         'passive create',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog(['layout destroy', 'passive destroy']);
@@ -2545,7 +2545,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root1 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root1.render(<App return={17} />);
         });
       }).toErrorDev([
@@ -2555,7 +2555,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root2 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root2.render(<App return={null} />);
         });
       }).toErrorDev([
@@ -2566,7 +2566,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root3 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root3.render(<App return={Promise.resolve()} />);
         });
       }).toErrorDev([
@@ -2924,7 +2924,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root1 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root1.render(<App return={17} />);
         });
       }).toErrorDev([
@@ -2934,7 +2934,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root2 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root2.render(<App return={null} />);
         });
       }).toErrorDev([
@@ -2945,7 +2945,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root3 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root3.render(<App return={Promise.resolve()} />);
         });
       }).toErrorDev([
@@ -2975,7 +2975,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root.render(<App />);
         });
       }).toErrorDev(['Warning: useInsertionEffect must not schedule updates.']);
@@ -2993,7 +2993,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         }, []);
         return null;
       }
-      await act(async () => {
+      await act(() => {
         root.render(<NotInsertion />);
       });
     });
@@ -3013,11 +3013,11 @@ describe('ReactHooksWithNoopRenderer', () => {
       }
 
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(<App foo="hello" />);
       });
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root.render(<App foo="goodbye" />);
         });
       }).toErrorDev(['Warning: useInsertionEffect must not schedule updates.']);
@@ -3035,7 +3035,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         }, []);
         return null;
       }
-      await act(async () => {
+      await act(() => {
         root.render(<NotInsertion />);
       });
     });
@@ -3204,7 +3204,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root1 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root1.render(<App return={17} />);
         });
       }).toErrorDev([
@@ -3214,7 +3214,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root2 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root2.render(<App return={null} />);
         });
       }).toErrorDev([
@@ -3225,7 +3225,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
       const root3 = ReactNoop.createRoot();
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           root3.render(<App return={Promise.resolve()} />);
         });
       }).toErrorDev([
@@ -3277,7 +3277,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         </>,
       );
 
-      await act(async () => button.current.increment());
+      await act(() => button.current.increment());
       assertLog([
         // Button should not re-render, because its props haven't changed
         // 'Increment',
@@ -3305,7 +3305,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       );
 
       // Callback should have updated
-      await act(async () => button.current.increment());
+      await act(() => button.current.increment());
       assertLog(['Count: 11']);
       expect(ReactNoop).toMatchRenderedOutput(
         <>
@@ -3423,7 +3423,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 0" />);
       expect(counter.current.count).toBe(0);
 
-      await act(async () => {
+      await act(() => {
         counter.current.dispatch(INCREMENT);
       });
       assertLog(['Count: 1']);
@@ -3453,7 +3453,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Count: 0" />);
       expect(counter.current.count).toBe(0);
 
-      await act(async () => {
+      await act(() => {
         counter.current.dispatch(INCREMENT);
       });
       assertLog(['Count: 1']);
@@ -3490,7 +3490,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       expect(counter.current.count).toBe(0);
       expect(totalRefUpdates).toBe(1);
 
-      await act(async () => {
+      await act(() => {
         counter.current.dispatch(INCREMENT);
       });
       assertLog(['Count: 1']);
@@ -3589,7 +3589,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
 
@@ -3687,7 +3687,7 @@ describe('ReactHooksWithNoopRenderer', () => {
         <span prop="A: 0, B: 0, C: [not loaded]" />,
       );
 
-      await act(async () => {
+      await act(() => {
         updateA(2);
         updateB(3);
       });
@@ -3749,7 +3749,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       ReactNoop.render(<App loadC={true} />);
       await waitForAll(['A: 0, B: 0, C: 0']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="A: 0, B: 0, C: 0" />);
-      await act(async () => {
+      await act(() => {
         updateA(2);
         updateB(3);
         updateC(4);
@@ -3855,7 +3855,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       expect(ReactNoop).toMatchRenderedOutput('1');
     });
 
-    await act(async () => {
+    await act(() => {
       setCounter(2);
     });
     assertLog(['Render: 1', 'Effect: 2', 'Reducer: 2', 'Render: 2']);
@@ -3890,7 +3890,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     await waitForAll(['Render disabled: true', 'Render count: 0']);
     expect(ReactNoop).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       // These increments should have no effect, since disabled=true
       increment();
       increment();
@@ -3899,7 +3899,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     assertLog(['Render disabled: true', 'Render count: 0']);
     expect(ReactNoop).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       // Enabling the updater should *not* replay the previous increment() actions
       setDisabled(false);
     });
@@ -3939,7 +3939,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     await waitForAll(['Render disabled: true', 'Render count: 0']);
     expect(ReactNoop).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       // These increments should have no effect, since disabled=true
       increment();
       increment();
@@ -3948,7 +3948,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     assertLog(['Render count: 0']);
     expect(ReactNoop).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       // Enabling the updater should *not* replay the previous increment() actions
       setDisabled(false);
     });
@@ -3988,7 +3988,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     await waitForAll(['Render disabled: true', 'Render count: 0']);
     expect(ReactNoop).toMatchRenderedOutput('0');
 
-    await act(async () => {
+    await act(() => {
       // Although the increment happens first (and would seem to do nothing since disabled=true),
       // because these calls are in a batch the parent updates first. This should cause the child
       // to re-render with disabled=false and *then* process the increment action, which now
@@ -4027,7 +4027,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     }
 
     const root = ReactNoop.createRoot(null);
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <CounterA />
@@ -4037,7 +4037,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     });
     assertLog(['Render A: 0', 'Render B: 0', 'Commit A: 0', 'Commit B: 0']);
 
-    await act(async () => {
+    await act(() => {
       setCounterA(1);
 
       // In the same batch, update B twice. To trigger the condition we're
@@ -4083,7 +4083,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     ]);
     expect(ReactNoop).toMatchRenderedOutput('0');
 
-    await act(async () => dispatch());
+    await act(() => dispatch());
     assertLog(['Step: 5, Shadow: 5']);
     expect(ReactNoop).toMatchRenderedOutput('5');
   });
@@ -4108,10 +4108,10 @@ describe('ReactHooksWithNoopRenderer', () => {
       return `${a ? 'A' : 'a'}${b ? 'B' : 'b'}${c ? 'C' : 'c'}`;
     }
 
-    await act(async () => ReactNoop.render(<App />));
+    await act(() => ReactNoop.render(<App />));
     expect(ReactNoop).toMatchRenderedOutput('abc');
 
-    await act(async () => {
+    await act(() => {
       updateA(true);
       // This update should not get dropped.
       updateC(true);
@@ -4138,7 +4138,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       return label;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Child key="A" label="A" />
@@ -4155,7 +4155,7 @@ describe('ReactHooksWithNoopRenderer', () => {
 
     // Delete A. This should only unmount the effect on A. In the regression,
     // B's effect would also unmount.
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Child key="B" label="B" />
@@ -4165,7 +4165,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     assertLog(['Unmount layout A', 'Unmount passive A']);
 
     // Now delete and unmount B.
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
     assertLog(['Unmount layout B', 'Unmount passive B']);
@@ -4184,7 +4184,7 @@ describe('ReactHooksWithNoopRenderer', () => {
       return label;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Child key="A" label="A" />
@@ -4194,7 +4194,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     });
     assertLog(['Mount A', 'Mount B']);
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Child key="B" label="B" />
@@ -4204,7 +4204,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     });
     assertLog([]);
 
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
 
@@ -4243,7 +4243,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Suspend! [A]', 'Suspend! [B]', 'Mount A', 'Mount B']);
@@ -4253,7 +4253,7 @@ describe('ReactHooksWithNoopRenderer', () => {
     });
     assertLog(['Promise resolved [A]', 'A', 'Suspend! [B]']);
 
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
     // In the regression, SuspenseList would cause the children to "forget" that
@@ -4280,25 +4280,25 @@ describe('ReactHooksWithNoopRenderer', () => {
       return <Text text={`Render: ${count}`} />;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<Test />);
     });
 
     assertLog(['Render: 0', 'Effect: 0']);
 
-    await act(async () => {
+    await act(() => {
       handleClick();
     });
 
     assertLog(['Render: 0']);
 
-    await act(async () => {
+    await act(() => {
       handleClick();
     });
 
     assertLog(['Render: 0']);
 
-    await act(async () => {
+    await act(() => {
       handleClick();
     });
 
diff --git a/packages/react-reconciler/src/__tests__/ReactIncrementalErrorHandling-test.internal.js b/packages/react-reconciler/src/__tests__/ReactIncrementalErrorHandling-test.internal.js
index 2507c5c9f42b9..285274fca0781 100644
--- a/packages/react-reconciler/src/__tests__/ReactIncrementalErrorHandling-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactIncrementalErrorHandling-test.internal.js
@@ -1832,7 +1832,7 @@ describe('ReactIncrementalErrorHandling', () => {
       return 'Everything is fine.';
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<Oops />);
     });
 
@@ -1890,14 +1890,14 @@ describe('ReactIncrementalErrorHandling', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App shouldThrow={false} />);
     });
     expect(root).toMatchRenderedOutput('All good');
 
     let error;
     try {
-      await act(async () => {
+      await act(() => {
         root.render(<App shouldThrow={true} />);
       });
     } catch (e) {
diff --git a/packages/react-reconciler/src/__tests__/ReactIncrementalScheduling-test.js b/packages/react-reconciler/src/__tests__/ReactIncrementalScheduling-test.js
index 27109f0b0b5e6..8c00ec741206e 100644
--- a/packages/react-reconciler/src/__tests__/ReactIncrementalScheduling-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactIncrementalScheduling-test.js
@@ -102,7 +102,7 @@ describe('ReactIncrementalScheduling', () => {
       return text;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.renderToRootWithID(<Text text="a:1" />, 'a');
       ReactNoop.renderToRootWithID(<Text text="b:1" />, 'b');
       ReactNoop.renderToRootWithID(<Text text="c:1" />, 'c');
diff --git a/packages/react-reconciler/src/__tests__/ReactIncrementalUpdates-test.js b/packages/react-reconciler/src/__tests__/ReactIncrementalUpdates-test.js
index dd88d959aacef..5fd12fee1f8bb 100644
--- a/packages/react-reconciler/src/__tests__/ReactIncrementalUpdates-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactIncrementalUpdates-test.js
@@ -618,13 +618,13 @@ describe('ReactIncrementalUpdates', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Committed: ']);
     expect(root).toMatchRenderedOutput(null);
 
-    await act(async () => {
+    await act(() => {
       React.startTransition(() => {
         pushToLog('A');
       });
@@ -679,13 +679,13 @@ describe('ReactIncrementalUpdates', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog([]);
     expect(root).toMatchRenderedOutput(null);
 
-    await act(async () => {
+    await act(() => {
       React.startTransition(() => {
         pushToLog('A');
       });
@@ -742,20 +742,20 @@ describe('ReactIncrementalUpdates', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App prop="A" />);
     });
     expect(root).toMatchRenderedOutput('0');
 
     // Changing the prop causes the count to increase by 100
-    await act(async () => {
+    await act(() => {
       root.render(<App prop="B" />);
     });
     expect(root).toMatchRenderedOutput('100');
 
     // Now increment the count by 1 with a state update. And, in the same
     // batch, change the prop back to its original value.
-    await act(async () => {
+    await act(() => {
       root.render(<App prop="A" />);
       app.setState(state => ({count: state.count + 1}));
     });
diff --git a/packages/react-reconciler/src/__tests__/ReactInterleavedUpdates-test.js b/packages/react-reconciler/src/__tests__/ReactInterleavedUpdates-test.js
index 5c520a4f8ab20..27e8652cb8ac4 100644
--- a/packages/react-reconciler/src/__tests__/ReactInterleavedUpdates-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactInterleavedUpdates-test.js
@@ -52,7 +52,7 @@ describe('ReactInterleavedUpdates', () => {
 
     const root = ReactNoop.createRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Child />
@@ -101,7 +101,7 @@ describe('ReactInterleavedUpdates', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A0', 'B0', 'C0']);
diff --git a/packages/react-reconciler/src/__tests__/ReactMemo-test.js b/packages/react-reconciler/src/__tests__/ReactMemo-test.js
index ca8c4d987d1e8..f50dc46d50914 100644
--- a/packages/react-reconciler/src/__tests__/ReactMemo-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactMemo-test.js
@@ -270,7 +270,7 @@ describe('memo', () => {
         }
 
         const root = ReactNoop.createRoot();
-        await act(async () => {
+        await act(() => {
           root.render(<App prop="A" />);
         });
         assertLog([
@@ -280,7 +280,7 @@ describe('memo', () => {
         ]);
 
         // Demonstrate what happens when the props change
-        await act(async () => {
+        await act(() => {
           root.render(<App prop="B" />);
         });
         assertLog([
@@ -294,7 +294,7 @@ describe('memo', () => {
 
         // Demonstrate what happens when the prop object changes but there's a
         // bailout because all the individual props are the same.
-        await act(async () => {
+        await act(() => {
           root.render(<App prop="B" />);
         });
         // Nothing re-renders
@@ -303,7 +303,7 @@ describe('memo', () => {
         // Demonstrate what happens when the prop object changes, it bails out
         // because all the props are the same, but we still render the
         // children because there's a local update in the same batch.
-        await act(async () => {
+        await act(() => {
           root.render(<App prop="B" />);
           setLocalUpdateOnChildren(1);
         });
@@ -316,7 +316,7 @@ describe('memo', () => {
         ]);
 
         // Do the same thing again. We should still reuse the props object.
-        await act(async () => {
+        await act(() => {
           root.render(<App prop="B" />);
           setLocalUpdateOnChildren(2);
         });
@@ -597,12 +597,12 @@ describe('memo', () => {
         }
 
         const root = ReactNoop.createRoot();
-        await act(async () => {
+        await act(() => {
           root.render(<App />);
         });
         expect(root).toMatchRenderedOutput('0');
 
-        await act(async () => {
+        await act(() => {
           setCounter(1);
           ReactNoop.discreteUpdates(() => {
             root.render(<App />);
@@ -633,12 +633,12 @@ describe('memo', () => {
         }
 
         const root = ReactNoop.createRoot();
-        await act(async () => {
+        await act(() => {
           root.render(<App />);
         });
         expect(root).toMatchRenderedOutput('0');
 
-        await act(async () => {
+        await act(() => {
           setCounter(1);
           ReactNoop.discreteUpdates(() => {
             root.render(<App />);
diff --git a/packages/react-reconciler/src/__tests__/ReactNoopRendererAct-test.js b/packages/react-reconciler/src/__tests__/ReactNoopRendererAct-test.js
index c607dfbc42432..7668e9ee855c8 100644
--- a/packages/react-reconciler/src/__tests__/ReactNoopRendererAct-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactNoopRendererAct-test.js
@@ -26,7 +26,7 @@ describe('internal act()', () => {
     }
 
     const calledLog = [];
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <App
           callback={() => {
@@ -54,7 +54,7 @@ describe('internal act()', () => {
       }, []);
       return ctr;
     }
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<App />);
     });
     assertLog(['stage 1', 'stage 2']);
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
index a3f56fb464926..120424ce1bf43 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreen-test.js
@@ -88,7 +88,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Now try after an update
-    await act(async () => {
+    await act(() => {
       root.render(<App mode="visible" />);
     });
     assertLog(['Normal', 'Deferred']);
@@ -128,7 +128,7 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createLegacyRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <LegacyHidden mode="hidden">
@@ -151,7 +151,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Test that the children can be updated
-    await act(async () => {
+    await act(() => {
       setState('B');
     });
     assertLog(['B']);
@@ -197,7 +197,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Test that the children can be updated
-    await act(async () => {
+    await act(() => {
       setState('B');
     });
     assertLog(['B']);
@@ -224,7 +224,7 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
 
     // Mount hidden tree.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <Child />
@@ -236,7 +236,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true} prop="Child" />);
 
     // Unhide the tree. The layout effect is mounted.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <Child />
@@ -260,7 +260,7 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <Child />
@@ -271,7 +271,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span prop="Child" />);
 
     // Hide the tree. The layout effect is unmounted.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <Child />
@@ -282,7 +282,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true} prop="Child" />);
 
     // Unhide the tree. The layout effect is re-mounted.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <Child />
@@ -313,7 +313,7 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       // Outer and inner offscreen are hidden.
       root.render(
         <Offscreen mode={'hidden'}>
@@ -327,7 +327,7 @@ describe('ReactOffscreen', () => {
     assertLog(['child']);
     expect(root).toMatchRenderedOutput(<span hidden={true} prop="child" />);
 
-    await act(async () => {
+    await act(() => {
       // Inner offscreen is visible.
       root.render(
         <Offscreen mode={'hidden'}>
@@ -341,7 +341,7 @@ describe('ReactOffscreen', () => {
     assertLog(['child']);
     expect(root).toMatchRenderedOutput(<span hidden={true} prop="child" />);
 
-    await act(async () => {
+    await act(() => {
       // Inner offscreen is hidden.
       root.render(
         <Offscreen mode={'hidden'}>
@@ -355,7 +355,7 @@ describe('ReactOffscreen', () => {
     assertLog(['child']);
     expect(root).toMatchRenderedOutput(<span hidden={true} prop="child" />);
 
-    await act(async () => {
+    await act(() => {
       // Inner offscreen is visible.
       root.render(
         <Offscreen mode={'hidden'}>
@@ -368,7 +368,7 @@ describe('ReactOffscreen', () => {
 
     Scheduler.unstable_clearLog();
 
-    await act(async () => {
+    await act(() => {
       // Outer offscreen is visible.
       // Inner offscreen is hidden.
       root.render(
@@ -382,7 +382,7 @@ describe('ReactOffscreen', () => {
 
     assertLog(['child']);
 
-    await act(async () => {
+    await act(() => {
       // Outer offscreen is hidden.
       // Inner offscreen is visible.
       root.render(
@@ -410,7 +410,7 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       // Start the tree hidden. The layout effect is not mounted.
       root.render(
         <Offscreen mode="hidden">
@@ -422,7 +422,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true} prop="Child" />);
 
     // Show the tree. The layout effect is mounted.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <Child />
@@ -433,7 +433,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span prop="Child" />);
 
     // Hide the tree again. The layout effect is un-mounted.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <Child />
@@ -459,7 +459,7 @@ describe('ReactOffscreen', () => {
       return <Text text="Child" />;
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <Child />
@@ -470,7 +470,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span prop="Child" />);
 
     // Hide the tree. The layout effect is unmounted.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <Child />
@@ -498,7 +498,7 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <LegacyHidden mode="visible">
           <Child />
@@ -507,7 +507,7 @@ describe('ReactOffscreen', () => {
     });
     assertLog(['Child', 'Mount layout']);
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <LegacyHidden mode="hidden">
           <Child />
@@ -516,7 +516,7 @@ describe('ReactOffscreen', () => {
     });
     assertLog(['Child']);
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <LegacyHidden mode="visible">
           <Child />
@@ -525,7 +525,7 @@ describe('ReactOffscreen', () => {
     });
     assertLog(['Child']);
 
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
     assertLog(['Unmount layout']);
@@ -534,7 +534,7 @@ describe('ReactOffscreen', () => {
   // @gate enableOffscreen
   it('hides new insertions into an already hidden tree', async () => {
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <span>Hi</span>
@@ -544,7 +544,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true}>Hi</span>);
 
     // Insert a new node into the hidden tree
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <span>Hi</span>
@@ -564,7 +564,7 @@ describe('ReactOffscreen', () => {
   // @gate enableOffscreen
   it('hides updated nodes inside an already hidden tree', async () => {
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <span>Hi</span>
@@ -574,7 +574,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true}>Hi</span>);
 
     // Set the `hidden` prop to on an already hidden node
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <span hidden={false}>Hi</span>
@@ -585,7 +585,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true}>Hi</span>);
 
     // Unhide the boundary
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <span hidden={true}>Hi</span>
@@ -596,7 +596,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true}>Hi</span>);
 
     // Remove the `hidden` prop
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <span>Hi</span>
@@ -670,7 +670,7 @@ describe('ReactOffscreen', () => {
 
     // Render a hidden tree
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App show={false} />);
     });
     assertLog(['Outer: 0', 'Inner: 0']);
@@ -751,7 +751,7 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Offscreen hidden={false} />);
     });
     assertLog([]);
@@ -803,7 +803,7 @@ describe('ReactOffscreen', () => {
     }
 
     // Initial render
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <Child />
@@ -816,7 +816,7 @@ describe('ReactOffscreen', () => {
     // Schedule an update to a hidden class component. The update will finish
     // rendering in the background, but the callback shouldn't fire yet, because
     // the component isn't visible.
-    await act(async () => {
+    await act(() => {
       child.setState({text: 'B'}, () => {
         Scheduler.log('B update finished');
       });
@@ -827,7 +827,7 @@ describe('ReactOffscreen', () => {
     // Now reveal the hidden component. Simultaneously, schedule another
     // update with a callback to the same component. When the component is
     // revealed, both the B callback and C callback should fire, in that order.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <Child />
@@ -860,7 +860,7 @@ describe('ReactOffscreen', () => {
 
     // Initial mount
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <Child />
@@ -870,7 +870,7 @@ describe('ReactOffscreen', () => {
     assertLog(['componentDidMount']);
 
     // Hide the class component
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="hidden">
           <Child />
@@ -881,7 +881,7 @@ describe('ReactOffscreen', () => {
 
     // Reappear the class component. componentDidMount should fire, not
     // componentDidUpdate.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Offscreen mode="visible">
           <Child />
@@ -908,7 +908,7 @@ describe('ReactOffscreen', () => {
 
       // Initial mount
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(
           <Offscreen mode="visible">
             <Child key="B" label="B" />
@@ -918,7 +918,7 @@ describe('ReactOffscreen', () => {
       assertLog(['Mount B']);
 
       // Hide the component
-      await act(async () => {
+      await act(() => {
         root.render(
           <Offscreen mode="hidden">
             <Child key="B" label="B" />
@@ -928,7 +928,7 @@ describe('ReactOffscreen', () => {
       assertLog(['Unmount B']);
 
       // Reappear the component and also add some new siblings.
-      await act(async () => {
+      await act(() => {
         root.render(
           <Offscreen mode="visible">
             <Child key="A" label="A" />
@@ -964,7 +964,7 @@ describe('ReactOffscreen', () => {
       // Initial mount
       const bRef = React.createRef();
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(
           <Offscreen mode="visible">
             <Child key="B" ref={bRef} label="B" />
@@ -978,7 +978,7 @@ describe('ReactOffscreen', () => {
       const setStateB = bRef.current.setState.bind(bRef.current);
 
       // Hide the component
-      await act(async () => {
+      await act(() => {
         root.render(
           <Offscreen mode="hidden">
             <Child key="B" ref={bRef} label="B" />
@@ -988,7 +988,7 @@ describe('ReactOffscreen', () => {
       assertLog(['Unmount B']);
 
       // Reappear the component and also add some new siblings.
-      await act(async () => {
+      await act(() => {
         setStateB(null, () => {
           Scheduler.log('setState callback B');
         });
@@ -1033,7 +1033,7 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
 
     // Mount the app without showing the extra content
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={false} />);
     });
     assertLog([
@@ -1056,7 +1056,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Reveal the prerendered tree
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={true} />);
     });
     assertLog([
@@ -1096,7 +1096,7 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
 
     // Mount the app without showing the extra content
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={false} />);
     });
     assertLog([
@@ -1119,7 +1119,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Reveal the prerendered tree
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={true} />);
     });
     assertLog(['Shell', 'More']);
@@ -1151,21 +1151,21 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App show={true} step={1} />);
     });
     assertLog([1, 'Commit mount [1]']);
     expect(root).toMatchRenderedOutput(<span prop={1} />);
 
     // Hide the tree. This will unmount the effect.
-    await act(async () => {
+    await act(() => {
       root.render(<App show={false} step={1} />);
     });
     assertLog(['Commit unmount [1]']);
     expect(root).toMatchRenderedOutput(<span hidden={true} prop={1} />);
 
     // Update.
-    await act(async () => {
+    await act(() => {
       root.render(<App show={false} step={2} />);
     });
     // The update is prerendered but no effects are fired
@@ -1173,7 +1173,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true} prop={2} />);
 
     // Reveal the tree.
-    await act(async () => {
+    await act(() => {
       root.render(<App show={true} step={2} />);
     });
     // The update doesn't render because it was already prerendered, but we do
@@ -1212,23 +1212,23 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App show={true} />);
     });
     assertLog(['Mount Child', 'Mount Parent']);
 
     // First demonstrate what happens during a normal deletion
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
     assertLog(['Unmount Parent', 'Unmount Child']);
 
     // Now redo the same thing but hide instead of deleting
-    await act(async () => {
+    await act(() => {
       root.render(<App show={true} />);
     });
     assertLog(['Mount Child', 'Mount Parent']);
-    await act(async () => {
+    await act(() => {
       root.render(<App show={false} />);
     });
     // The order is the same as during a deletion: parent before child
@@ -1266,7 +1266,7 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
 
     // Mount the app, including the extra content
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={true} step={1} />);
     });
     assertLog(['Shell 1', 'More 1', 'Mount Shell 1', 'Mount More 1']);
@@ -1278,7 +1278,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Hide the extra content. while also updating one of its props
-    await act(async () => {
+    await act(() => {
       root.render(<App showMore={false} step={2} />);
     });
     assertLog([
@@ -1333,7 +1333,7 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
 
     // Prerender the outer contents. No effects should mount.
-    await act(async () => {
+    await act(() => {
       root.render(<App showOuter={false} showInner={false} />);
     });
     assertLog(['Outer']);
@@ -1344,7 +1344,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Prerender the inner contents. No effects should mount.
-    await act(async () => {
+    await act(() => {
       root.render(<App showOuter={false} showInner={true} />);
     });
     assertLog(['Outer', 'Inner']);
@@ -1358,7 +1358,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Reveal the prerendered tree
-    await act(async () => {
+    await act(() => {
       root.render(<App showOuter={true} showInner={true} />);
     });
     // The effects fire, but the tree is not re-rendered because it already
@@ -1409,7 +1409,7 @@ describe('ReactOffscreen', () => {
     const root = ReactNoop.createRoot();
 
     // Prerender the whole tree.
-    await act(async () => {
+    await act(() => {
       root.render(<App showOuter={false} showInner={false} />);
     });
     assertLog(['Outer', 'Inner']);
@@ -1426,7 +1426,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Reveal the outer contents. The inner tree remains hidden.
-    await act(async () => {
+    await act(() => {
       root.render(<App showOuter={true} showInner={false} />);
     });
     assertLog(['Mount Outer']);
@@ -1460,25 +1460,25 @@ describe('ReactOffscreen', () => {
 
       const root = ReactNoop.createRoot();
 
-      await act(async () => {
+      await act(() => {
         root.render(<App mode={'manual'} />);
       });
 
       expect(offscreenRef.current).not.toBeNull();
 
-      await act(async () => {
+      await act(() => {
         root.render(<App mode={'visible'} />);
       });
 
       expect(offscreenRef.current).toBeNull();
 
-      await act(async () => {
+      await act(() => {
         root.render(<App mode={'hidden'} />);
       });
 
       expect(offscreenRef.current).toBeNull();
 
-      await act(async () => {
+      await act(() => {
         root.render(<App mode={'manual'} />);
       });
 
@@ -1525,7 +1525,7 @@ describe('ReactOffscreen', () => {
 
       const root = ReactNoop.createRoot();
 
-      await act(async () => {
+      await act(() => {
         root.render(<App />);
       });
 
@@ -1552,7 +1552,7 @@ describe('ReactOffscreen', () => {
         );
       });
 
-      await act(async () => {
+      await act(() => {
         offscreenRef.current.detach();
       });
 
@@ -1577,7 +1577,7 @@ describe('ReactOffscreen', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         offscreenRef.current.attach();
       });
 
@@ -1650,7 +1650,7 @@ describe('ReactOffscreen', () => {
 
       const root = ReactNoop.createRoot();
 
-      await act(async () => {
+      await act(() => {
         root.render(<App />);
       });
 
@@ -1721,19 +1721,19 @@ describe('ReactOffscreen', () => {
 
     const root = ReactNoop.createRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App showOffscreen={true} />);
     });
 
     expect(offscreenRef.current).not.toBeNull();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App showOffscreen={false} />);
     });
 
     expect(offscreenRef.current).toBeNull();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App showOffscreen={true} />);
     });
 
@@ -1757,18 +1757,18 @@ describe('ReactOffscreen', () => {
 
     const root = ReactNoop.createRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App mode={'hidden'} />);
     });
 
     expect(offscreenRef.current).toBeNull();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App mode={'visible'} />);
     });
 
     expect(offscreenRef.current).not.toBeNull();
-    await act(async () => {
+    await act(() => {
       root.render(<App mode={'hidden'} />);
     });
 
@@ -1789,7 +1789,7 @@ describe('ReactOffscreen', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <App>
           <div />
@@ -1800,7 +1800,7 @@ describe('ReactOffscreen', () => {
     expect(offscreenRef.current).not.toBeNull();
     const firstFiber = offscreenRef.current._current;
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <App>
           <span />
@@ -1844,7 +1844,7 @@ describe('ReactOffscreen', () => {
 
     const root = ReactNoop.createRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
 
@@ -1852,7 +1852,7 @@ describe('ReactOffscreen', () => {
     expect(spanRef.current).not.toBeNull();
     assertLog(['Mount Layout Child', 'Mount Child']);
 
-    await act(async () => {
+    await act(() => {
       offscreenRef.detach();
     });
 
@@ -1860,13 +1860,13 @@ describe('ReactOffscreen', () => {
     assertLog(['Unmount Layout Child', 'Unmount Child']);
 
     // Calling attach on already attached Offscreen.
-    await act(async () => {
+    await act(() => {
       offscreenRef.detach();
     });
 
     assertLog([]);
 
-    await act(async () => {
+    await act(() => {
       offscreenRef.attach();
     });
 
@@ -1900,7 +1900,7 @@ describe('ReactOffscreen', () => {
 
     const root = ReactNoop.createRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
 
@@ -1919,7 +1919,7 @@ describe('ReactOffscreen', () => {
     expect(outerOffscreen).not.toBeNull();
     expect(innerOffscreen).not.toBeNull();
 
-    await act(async () => {
+    await act(() => {
       outerOffscreen.detach();
     });
 
@@ -1932,7 +1932,7 @@ describe('ReactOffscreen', () => {
       'unmount inner',
     ]);
 
-    await act(async () => {
+    await act(() => {
       outerOffscreen.attach();
     });
 
@@ -1943,26 +1943,26 @@ describe('ReactOffscreen', () => {
       'mount middle',
     ]);
 
-    await act(async () => {
+    await act(() => {
       innerOffscreen.detach();
     });
 
     assertLog(['unmount layout inner', 'unmount inner']);
 
     // Calling detach on already detached Offscreen.
-    await act(async () => {
+    await act(() => {
       innerOffscreen.detach();
     });
 
     assertLog([]);
 
-    await act(async () => {
+    await act(() => {
       innerOffscreen.attach();
     });
 
     assertLog(['mount layout inner', 'mount inner']);
 
-    await act(async () => {
+    await act(() => {
       innerOffscreen.detach();
       outerOffscreen.attach();
     });
@@ -1992,13 +1992,13 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
 
     assertLog(['attach child']);
 
-    await act(async () => {
+    await act(() => {
       const instance = offscreen.current;
       // Detach then immediately attach the instance.
       instance.detach();
@@ -2007,14 +2007,14 @@ describe('ReactOffscreen', () => {
 
     assertLog([]);
 
-    await act(async () => {
+    await act(() => {
       const instance = offscreen.current;
       instance.detach();
     });
 
     assertLog(['detach child']);
 
-    await act(async () => {
+    await act(() => {
       const instance = offscreen.current;
       // Attach then immediately detach.
       instance.attach();
@@ -2052,7 +2052,7 @@ describe('ReactOffscreen', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['attach child']);
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
index bfe200ee35465..129d4d0ddc8e0 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreenStrictMode-test.js
@@ -33,7 +33,7 @@ describe('ReactOffscreenStrictMode', () => {
 
   // @gate __DEV__ && enableOffscreen
   it('should trigger strict effects when offscreen is visible', async () => {
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="visible">
@@ -57,7 +57,7 @@ describe('ReactOffscreenStrictMode', () => {
 
   // @gate __DEV__ && enableOffscreen && useModernStrictMode
   it('should not trigger strict effects when offscreen is hidden', async () => {
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="hidden">
@@ -71,7 +71,7 @@ describe('ReactOffscreenStrictMode', () => {
 
     log = [];
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="hidden">
@@ -86,7 +86,7 @@ describe('ReactOffscreenStrictMode', () => {
 
     log = [];
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="visible">
@@ -109,7 +109,7 @@ describe('ReactOffscreenStrictMode', () => {
 
     log = [];
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="hidden">
@@ -143,7 +143,7 @@ describe('ReactOffscreenStrictMode', () => {
       return state;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.StrictMode>
           <React.Suspense>
@@ -193,7 +193,7 @@ describe('ReactOffscreenStrictMode', () => {
       return null;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.StrictMode>
           <Offscreen mode="visible">
@@ -205,7 +205,7 @@ describe('ReactOffscreenStrictMode', () => {
 
     log.push('------------------------------');
 
-    await act(async () => {
+    await act(() => {
       resolve();
       shouldSuspend = false;
     });
diff --git a/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js b/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
index dfbd37a477123..3a09abd9b10b7 100644
--- a/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactOffscreenSuspense-test.js
@@ -118,7 +118,7 @@ describe('ReactOffscreen', () => {
     // The hidden tree hasn't finished loading, but we should still be able to
     // show the surrounding contents. The outer Suspense boundary
     // isn't affected.
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Visible', 'Suspend! [Hidden]']);
@@ -158,7 +158,7 @@ describe('ReactOffscreen', () => {
     }
 
     // Unlike Offscreen, LegacyHidden never captures if something suspends
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Visible', 'Suspend! [Hidden]', 'Loading...']);
@@ -192,7 +192,7 @@ describe('ReactOffscreen', () => {
     // The hidden tree hasn't finished loading, but we should still be able to
     // show the surrounding contents. It doesn't matter that there's no
     // Suspense boundary because the unfinished content isn't visible.
-    await act(async () => {
+    await act(() => {
       root.render(
         <Details open={false}>
           <AsyncText text="Async" />
@@ -204,7 +204,7 @@ describe('ReactOffscreen', () => {
 
     // But when we switch the boundary from hidden to visible, it should
     // now bubble to the nearest Suspense boundary.
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Details open={true}>
@@ -249,7 +249,7 @@ describe('ReactOffscreen', () => {
     }
 
     // Initial mount. Nothing suspends
-    await act(async () => {
+    await act(() => {
       root.render(
         <Details open={true}>
           <Text text="(empty)" />
@@ -265,7 +265,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Update that suspends inside the currently visible tree
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Details open={true}>
@@ -285,7 +285,7 @@ describe('ReactOffscreen', () => {
     );
 
     // Update that hides the suspended tree
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Details open={false}>
@@ -338,12 +338,12 @@ describe('ReactOffscreen', () => {
 
     const root = ReactNoop.createRoot();
     resolveText('A');
-    await act(async () => {
+    await act(() => {
       root.render(<App show={false} />);
     });
     assertLog(['A']);
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         setText('B');
       });
@@ -376,13 +376,13 @@ describe('ReactOffscreen', () => {
 
     const root = ReactNoop.createRoot();
     resolveText('A0');
-    await act(async () => {
+    await act(() => {
       root.render(<App show={false} />);
     });
     assertLog(['A0']);
     expect(root).toMatchRenderedOutput(<span hidden={true}>A0</span>);
 
-    await act(async () => {
+    await act(() => {
       React.startTransition(() => {
         setStep(1);
       });
@@ -400,7 +400,7 @@ describe('ReactOffscreen', () => {
     expect(root).toMatchRenderedOutput(<span hidden={true}>A0</span>);
 
     // Resolve the data and finish rendering
-    await act(async () => {
+    await act(() => {
       resolveText('B1');
     });
     assertLog(['B1']);
@@ -462,7 +462,7 @@ describe('ReactOffscreen', () => {
     // Render a hidden tree
     const root = ReactNoop.createRoot();
     resolveText('Async: 0');
-    await act(async () => {
+    await act(() => {
       root.render(<App show={true} />);
     });
     assertLog([
diff --git a/packages/react-reconciler/src/__tests__/ReactSchedulerIntegration-test.js b/packages/react-reconciler/src/__tests__/ReactSchedulerIntegration-test.js
index 7af23a8261aca..4f40b5dc3e718 100644
--- a/packages/react-reconciler/src/__tests__/ReactSchedulerIntegration-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactSchedulerIntegration-test.js
@@ -79,11 +79,11 @@ describe('ReactSchedulerIntegration', () => {
       });
       return null;
     }
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<CleanupEffect />);
     });
     assertLog([]);
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<Effects />);
     });
     assertLog([
diff --git a/packages/react-reconciler/src/__tests__/ReactSubtreeFlagsWarning-test.js b/packages/react-reconciler/src/__tests__/ReactSubtreeFlagsWarning-test.js
index d795aca8053ac..49bde67837cdf 100644
--- a/packages/react-reconciler/src/__tests__/ReactSubtreeFlagsWarning-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactSubtreeFlagsWarning-test.js
@@ -161,7 +161,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
     // On initial mount, the suspended component is committed in an incomplete
     // state, without a passive static effect flag.
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Suspend! [Async]']);
@@ -170,7 +170,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
     // When the promise resolves, a passive static effect flag is added. In the
     // regression, the "missing expected static flag" would fire, because the
     // previous fiber did not have one.
-    await act(async () => {
+    await act(() => {
       resolveText('Async');
     });
     assertLog(['Async', 'Effect']);
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspense-test.internal.js b/packages/react-reconciler/src/__tests__/ReactSuspense-test.internal.js
index 19413e8987063..d9a8f78d6bd27 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspense-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspense-test.internal.js
@@ -410,7 +410,7 @@ describe('ReactSuspense', () => {
     await waitForAll(['default']);
     expect(root).toMatchRenderedOutput('default');
 
-    await act(async () => setValue('new value'));
+    await act(() => setValue('new value'));
     assertLog(['Suspend! [new value]', 'Loading...']);
 
     await resolveText('new value');
@@ -456,7 +456,7 @@ describe('ReactSuspense', () => {
     await waitForAll(['default']);
     expect(root).toMatchRenderedOutput('default');
 
-    await act(async () => setValue('new value'));
+    await act(() => setValue('new value'));
     assertLog(['Suspend! [new value]', 'Loading...']);
 
     await resolveText('new value');
@@ -500,7 +500,7 @@ describe('ReactSuspense', () => {
     await waitForAll(['default']);
     expect(root).toMatchRenderedOutput('default');
 
-    await act(async () => setValue('new value'));
+    await act(() => setValue('new value'));
     assertLog(['Suspend! [new value]', 'Loading...']);
 
     await resolveText('new value');
@@ -544,7 +544,7 @@ describe('ReactSuspense', () => {
     await waitForAll(['default']);
     expect(root).toMatchRenderedOutput('default');
 
-    await act(async () => setValue('new value'));
+    await act(() => setValue('new value'));
     assertLog(['Suspend! [new value]', 'Loading...']);
 
     await resolveText('new value');
@@ -583,7 +583,7 @@ describe('ReactSuspense', () => {
     await waitForAll(['Child 1', 'create layout']);
     expect(root).toMatchRenderedOutput('Child 1');
 
-    await act(async () => {
+    await act(() => {
       _setShow(true);
     });
     assertLog([
@@ -856,7 +856,7 @@ describe('ReactSuspense', () => {
       expect(root).toMatchRenderedOutput('Step: 1');
 
       // Update that suspends
-      await act(async () => {
+      await act(() => {
         instance.setState({step: 2});
       });
       assertLog(['Suspend! [Step: 2]', 'Loading...']);
@@ -976,7 +976,7 @@ describe('ReactSuspense', () => {
       await waitForPaint(['Tab: 0']);
       expect(root).toMatchRenderedOutput('Tab: 0 + sibling');
 
-      await act(async () => setTab(1));
+      await act(() => setTab(1));
       assertLog(['Suspend! [Tab: 1]', ' + sibling', 'Loading...']);
       expect(root).toMatchRenderedOutput('Loading...');
 
@@ -984,7 +984,7 @@ describe('ReactSuspense', () => {
       await waitForPaint(['Tab: 1']);
       expect(root).toMatchRenderedOutput('Tab: 1 + sibling');
 
-      await act(async () => setTab(2));
+      await act(() => setTab(2));
       assertLog(['Suspend! [Tab: 2]', ' + sibling', 'Loading...']);
       expect(root).toMatchRenderedOutput('Loading...');
 
@@ -1018,11 +1018,11 @@ describe('ReactSuspense', () => {
       await waitForPaint(['A:0']);
       expect(root).toMatchRenderedOutput('A:0');
 
-      await act(async () => setStep(1));
+      await act(() => setStep(1));
       assertLog(['Suspend! [A:1]', 'Loading...']);
       expect(root).toMatchRenderedOutput('Loading...');
 
-      await act(async () => {
+      await act(() => {
         root.update(null);
       });
     });
@@ -1103,7 +1103,7 @@ describe('ReactSuspense', () => {
 
       const root = ReactTestRenderer.create(null);
 
-      await act(async () => {
+      await act(() => {
         root.update(<App name="world" />);
       });
     });
@@ -1139,7 +1139,7 @@ describe('ReactSuspense', () => {
       await waitForPaint(['default']);
       expect(root).toMatchRenderedOutput('default');
 
-      await act(async () => setValue('new value'));
+      await act(() => setValue('new value'));
       assertLog(['Suspend! [new value]', 'Loading...']);
 
       await resolveText('new value');
@@ -1183,7 +1183,7 @@ describe('ReactSuspense', () => {
       await waitForPaint(['default']);
       expect(root).toMatchRenderedOutput('default');
 
-      await act(async () => setValue('new value'));
+      await act(() => setValue('new value'));
       assertLog(['Suspend! [new value]', 'Loading...']);
 
       await resolveText('new value');
@@ -1226,7 +1226,7 @@ describe('ReactSuspense', () => {
       await waitForPaint(['default']);
       expect(root).toMatchRenderedOutput('default');
 
-      await act(async () => setValue('new value'));
+      await act(() => setValue('new value'));
       assertLog(['Suspend! [new value]', 'Loading...']);
 
       await resolveText('new value');
@@ -1265,7 +1265,7 @@ describe('ReactSuspense', () => {
       await waitForPaint(['default']);
       expect(root).toMatchRenderedOutput('default');
 
-      await act(async () => setValue('new value'));
+      await act(() => setValue('new value'));
       assertLog(['Suspend! [new value]', 'Loading...']);
 
       await resolveText('new value');
@@ -1316,11 +1316,11 @@ describe('ReactSuspense', () => {
       assertLog(['Received context value [default]', 'default']);
       expect(root).toMatchRenderedOutput('default');
 
-      await act(async () => setValue('new value'));
+      await act(() => setValue('new value'));
       assertLog(['Received context value [new value]', 'Loading...']);
       expect(root).toMatchRenderedOutput('Loading...');
 
-      await act(async () => setValue('default'));
+      await act(() => setValue('default'));
       assertLog(['Received context value [default]', 'default']);
       expect(root).toMatchRenderedOutput('default');
     });
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspenseEffectsSemantics-test.js b/packages/react-reconciler/src/__tests__/ReactSuspenseEffectsSemantics-test.js
index 3da25f2467f67..e8d81970ad5f7 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspenseEffectsSemantics-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspenseEffectsSemantics-test.js
@@ -255,7 +255,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount and suspend.
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App>
             <AsyncText text="Async" ms={1000} />
@@ -308,7 +308,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -374,7 +374,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount and suspend.
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderLegacySyncRoot(
           <App>
             <AsyncText text="Async" ms={1000} />
@@ -427,7 +427,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderLegacySyncRoot(null);
       });
       assertLog([
@@ -475,7 +475,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderLegacySyncRoot(<App />);
       });
       assertLog([
@@ -501,7 +501,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       );
 
       // Schedule an update that causes React to suspend.
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderLegacySyncRoot(
           <App>
             <AsyncText text="Async" ms={1000} />
@@ -560,7 +560,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderLegacySyncRoot(null);
       });
       assertLog([
@@ -605,7 +605,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -696,7 +696,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -762,7 +762,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -849,7 +849,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
           <span prop="Outside" />
         </>,
       );
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -890,7 +890,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -973,7 +973,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -1017,7 +1017,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -1100,7 +1100,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -1131,7 +1131,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -1150,7 +1150,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       );
 
       // Suspend the inner Suspense subtree (only inner effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App innerChildren={<AsyncText text="InnerAsync_1" ms={1000} />} />,
         );
@@ -1174,7 +1174,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
 
       // Suspend the outer Suspense subtree (outer effects and inner fallback effects should be destroyed)
       // (This check also ensures we don't destroy effects for mounted inner fallback.)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App
             outerChildren={<AsyncText text="OuterAsync_1" ms={1000} />}
@@ -1224,7 +1224,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       );
 
       // Suspend the inner Suspense subtree (no effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App
             outerChildren={<AsyncText text="OuterAsync_1" ms={1000} />}
@@ -1299,7 +1299,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       );
 
       // Suspend the outer Suspense subtree (all effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App
             outerChildren={<AsyncText text="OuterAsync_2" ms={1000} />}
@@ -1372,7 +1372,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -1391,7 +1391,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       );
 
       // Suspend the inner Suspense subtree (only inner effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App innerChildren={<AsyncText text="InnerAsync_1" ms={1000} />} />,
         );
@@ -1415,7 +1415,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
 
       // Suspend the outer Suspense subtree (outer effects and inner fallback effects should be destroyed)
       // (This check also ensures we don't destroy effects for mounted inner fallback.)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App
             outerChildren={<AsyncText text="OuterAsync_1" ms={1000} />}
@@ -1498,7 +1498,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -1650,7 +1650,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -1669,7 +1669,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       );
 
       // Suspend both the outer boundary and the fallback
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App
             outerChildren={<AsyncText text="OutsideAsync" ms={1000} />}
@@ -1771,7 +1771,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App shouldSuspend={false} />);
       });
       assertLog([
@@ -1880,7 +1880,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
           );
         }
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App />
@@ -1909,7 +1909,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
 
         // Schedule an update that causes React to suspend.
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App>
@@ -2016,7 +2016,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
           );
         }
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App />
@@ -2045,7 +2045,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
 
         // Schedule an update that suspends and triggers our error code.
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App>
@@ -2128,7 +2128,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
           );
         }
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App />
@@ -2157,7 +2157,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
 
         // Schedule an update that causes React to suspend.
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App>
@@ -2265,7 +2265,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
           );
         }
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App />
@@ -2294,7 +2294,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
 
         // Schedule an update that suspends and triggers our error code.
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App>
@@ -2371,7 +2371,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -2471,7 +2471,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -2527,7 +2527,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -2623,7 +2623,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -2711,7 +2711,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderLegacySyncRoot(<App />);
       });
       assertLog([
@@ -2729,7 +2729,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       expect(ReactNoop).toMatchRenderedOutput(null);
 
       // Suspend the inner Suspense subtree (only inner effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderLegacySyncRoot(
           <App children={<AsyncText text="Async" ms={1000} />} />,
         );
@@ -2762,7 +2762,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       ]);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Async" />);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.renderLegacySyncRoot(null);
       });
       assertLog([
@@ -2789,7 +2789,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -2810,7 +2810,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       );
 
       // Suspend the inner Suspense subtree (only inner effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App children={<AsyncText text="Async" ms={1000} />} />,
         );
@@ -2864,7 +2864,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -2898,7 +2898,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -2916,7 +2916,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       expect(ReactNoop).toMatchRenderedOutput(null);
 
       // Suspend the inner Suspense subtree (only inner effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App children={<AsyncText text="Async" ms={1000} />} />,
         );
@@ -2962,7 +2962,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       ]);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Async" />);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -3002,7 +3002,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -3020,7 +3020,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       expect(ReactNoop).toMatchRenderedOutput(null);
 
       // Suspend the inner Suspense subtree (only inner effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App children={<AsyncText text="Async" ms={1000} />} />,
         );
@@ -3066,7 +3066,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       ]);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Async" />);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -3117,7 +3117,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       }
 
       // Mount
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
       assertLog([
@@ -3129,7 +3129,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       expect(ReactNoop).toMatchRenderedOutput(null);
 
       // Suspend the inner Suspense subtree (only inner effects should be destroyed)
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(
           <App children={<AsyncText text="Async" ms={1000} />} />,
         );
@@ -3161,7 +3161,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
       ]);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Async" />);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
       assertLog([
@@ -3210,7 +3210,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
           );
         }
 
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App />
@@ -3239,7 +3239,7 @@ describe('ReactSuspenseEffectsSemantics', () => {
         );
 
         // Schedule an update that causes React to suspend.
-        await act(async () => {
+        await act(() => {
           ReactNoop.render(
             <ErrorBoundary fallback={<Text text="Error" />}>
               <App>
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspenseEffectsSemanticsDOM-test.js b/packages/react-reconciler/src/__tests__/ReactSuspenseEffectsSemanticsDOM-test.js
index 760e4d1cc27ee..8988cbd692de3 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspenseEffectsSemanticsDOM-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspenseEffectsSemanticsDOM-test.js
@@ -129,12 +129,12 @@ describe('ReactSuspenseEffectsSemanticsDOM', () => {
       return null;
     }
 
-    await act(async () => {
+    await act(() => {
       const root = ReactDOMClient.createRoot(container);
       root.render(<App />);
     });
 
-    await act(async () => {
+    await act(() => {
       scheduleSuspendingUpdate();
     });
   });
@@ -182,7 +182,7 @@ describe('ReactSuspenseEffectsSemanticsDOM', () => {
     }
 
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Parent swap={false} />);
     });
     assertLog(['Loading...']);
@@ -242,7 +242,7 @@ describe('ReactSuspenseEffectsSemanticsDOM', () => {
     }
 
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Parent swap={false} />);
     });
     assertLog(['Loading...']);
@@ -294,7 +294,7 @@ describe('ReactSuspenseEffectsSemanticsDOM', () => {
     }
 
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Parent swap={false} />);
     });
     assertLog(['Loading...']);
@@ -361,7 +361,7 @@ describe('ReactSuspenseEffectsSemanticsDOM', () => {
     }
 
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Parent swap={false} />);
     });
     assertLog(['Loading...']);
@@ -424,7 +424,7 @@ describe('ReactSuspenseEffectsSemanticsDOM', () => {
     }
 
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Parent swap={false} />);
     });
     assertLog(['Loading...']);
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspenseFuzz-test.internal.js b/packages/react-reconciler/src/__tests__/ReactSuspenseFuzz-test.internal.js
index 169be192ba669..9ec744b430feb 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspenseFuzz-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspenseFuzz-test.internal.js
@@ -145,7 +145,7 @@ describe('ReactSuspenseFuzz', () => {
         if ((elapsedTime += 1000) > 1000000) {
           throw new Error('Something did not resolve properly.');
         }
-        await act(async () => {
+        await act(() => {
           ReactNoop.batchedUpdates(() => {
             jest.advanceTimersByTime(1000);
           });
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspenseList-test.js b/packages/react-reconciler/src/__tests__/ReactSuspenseList-test.js
index a33c68cc7f6c2..38b37190dc705 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspenseList-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspenseList-test.js
@@ -298,7 +298,7 @@ describe('ReactSuspenseList', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       C.resolve();
     });
 
@@ -312,7 +312,7 @@ describe('ReactSuspenseList', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       B.resolve();
     });
 
@@ -2275,7 +2275,7 @@ describe('ReactSuspenseList', () => {
     );
 
     // Update the row adjacent to the list
-    await act(async () => updateAdjacent('C'));
+    await act(() => updateAdjacent('C'));
 
     assertLog(['C']);
 
@@ -2332,7 +2332,7 @@ describe('ReactSuspenseList', () => {
     const previousInst = setAsyncB;
 
     // During an update we suspend on B.
-    await act(async () => setAsyncB(true));
+    await act(() => setAsyncB(true));
 
     assertLog([
       'Suspend! [B]',
@@ -2350,7 +2350,7 @@ describe('ReactSuspenseList', () => {
 
     // Before we resolve we'll rerender the whole list.
     // This should leave the tree intact.
-    await act(async () => ReactNoop.render(<Foo updateList={true} />));
+    await act(() => ReactNoop.render(<Foo updateList={true} />));
 
     assertLog(['A', 'Suspend! [B]', 'Loading B']);
 
@@ -2421,7 +2421,7 @@ describe('ReactSuspenseList', () => {
     const previousInst = setAsyncB;
 
     // During an update we suspend on B.
-    await act(async () => setAsyncB(true));
+    await act(() => setAsyncB(true));
 
     assertLog([
       'Suspend! [B]',
@@ -2439,7 +2439,7 @@ describe('ReactSuspenseList', () => {
 
     // Before we resolve we'll rerender the whole list.
     // This should leave the tree intact.
-    await act(async () => ReactNoop.render(<Foo updateList={true} />));
+    await act(() => ReactNoop.render(<Foo updateList={true} />));
 
     assertLog(['A', 'Suspend! [B]', 'Loading B']);
 
diff --git a/packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.js b/packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.js
index e21b01f97adb1..e430b9ef3536d 100644
--- a/packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.js
@@ -665,7 +665,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
     // Mount the Suspense boundary without suspending, so that the subsequent
     // updates suspend with a delay.
-    await act(async () => {
+    await act(() => {
       root.render(<App step={0} shouldSuspend={false} />);
     });
     await advanceTimers(1000);
@@ -1242,7 +1242,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       assertLog(['Suspend! [Result]', 'Loading...']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Loading..." />);
 
-      await act(async () => {
+      await act(() => {
         resolveText('Result');
       });
 
@@ -1312,7 +1312,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         resolveText('Step: 2');
       });
       assertLog(['Step: 2']);
@@ -1385,7 +1385,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
         </>,
       );
 
-      await act(async () => {
+      await act(() => {
         resolveText('B');
       });
 
@@ -1427,7 +1427,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       assertLog(['constructor', 'Suspend! [Hi]', 'Loading...']);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Loading..." />);
 
-      await act(async () => {
+      await act(() => {
         resolveText('Hi');
       });
 
@@ -1470,7 +1470,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
         'Loading...',
       ]);
       expect(ReactNoop).toMatchRenderedOutput(<span prop="Loading..." />);
-      await act(async () => {
+      await act(() => {
         resolveText('Hi');
       });
       assertLog(['Hi']);
@@ -1516,7 +1516,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
           </>,
         ]);
 
-        await act(async () => {
+        await act(() => {
           resolveText('Hi');
         });
         assertLog(['Hi']);
@@ -1557,7 +1557,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
           'Child is hidden: true',
         ]);
 
-        await act(async () => {
+        await act(() => {
           resolveText('Hi');
         });
 
@@ -1630,20 +1630,20 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       }
 
       const root = ReactNoop.createLegacyRoot(null);
-      await act(async () => {
+      await act(() => {
         root.render(<App />);
       });
       assertLog(['Mount']);
       expect(root).toMatchRenderedOutput('Child');
 
       // Suspend the child. This puts it into an inconsistent state.
-      await act(async () => {
+      await act(() => {
         setShouldSuspend(true);
       });
       expect(root).toMatchRenderedOutput('Loading...');
 
       // Unmount everything
-      await act(async () => {
+      await act(() => {
         root.render(null);
       });
       assertLog(['Unmount']);
@@ -1799,7 +1799,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       resolveText('B');
     });
 
@@ -1835,7 +1835,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       'Effect [Loading...]',
     ]);
 
-    await act(async () => {
+    await act(() => {
       resolveText('B2');
     });
 
@@ -2081,12 +2081,12 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<App />);
     });
 
     // TODO: assert toErrorDev() when the warning is implemented again.
-    await act(async () => {
+    await act(() => {
       ReactNoop.flushSync(() => _setShow(true));
     });
   });
@@ -2108,12 +2108,12 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<App />);
     });
 
     // TODO: assert toErrorDev() when the warning is implemented again.
-    await act(async () => {
+    await act(() => {
       ReactNoop.flushSync(() => show());
     });
   });
@@ -2135,14 +2135,14 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<App />);
     });
 
     assertLog(['Suspend! [A]']);
     expect(ReactNoop).toMatchRenderedOutput('Loading...');
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.flushSync(() => showB());
     });
 
@@ -2168,12 +2168,12 @@ describe('ReactSuspenseWithNoopRenderer', () => {
           </Suspense>
         );
       }
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
 
       // TODO: assert toErrorDev() when the warning is implemented again.
-      await act(async () => {
+      await act(() => {
         ReactNoop.flushSync(() => _setShow(true));
       });
     },
@@ -2195,12 +2195,12 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<App />);
     });
 
     // also make sure lowpriority is okay
-    await act(async () => show(true));
+    await act(() => show(true));
 
     assertLog(['Suspend! [A]']);
     await resolveText('A');
@@ -2221,12 +2221,12 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<App />);
     });
 
     // also make sure lowpriority is okay
-    await act(async () => _setShow(true));
+    await act(() => _setShow(true));
 
     assertLog(['Suspend! [A]']);
     await resolveText('A');
@@ -2993,7 +2993,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App text="Initial" />);
     });
     assertLog(['Suspend! [Initial]']);
@@ -3054,7 +3054,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
 
@@ -3211,7 +3211,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       }
 
       await seedNextTextCache('A');
-      await act(async () => {
+      await act(() => {
         root.render(<Parent />);
       });
       assertLog(['A']);
@@ -3265,7 +3265,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       }
 
       await seedNextTextCache('A');
-      await act(async () => {
+      await act(() => {
         root.render(<Parent />);
       });
       assertLog(['A']);
@@ -3334,7 +3334,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
       // Resolve the initial tree
       await seedNextTextCache('A');
-      await act(async () => {
+      await act(() => {
         root.render(<App />);
       });
       assertLog(['A']);
@@ -3356,7 +3356,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       // Schedule a default pri update on the boundary, and a lower pri update
       // on the fallback. We're testing to make sure the fallback can still
       // update even though the primary tree is suspended.
-      await act(async () => {
+      await act(() => {
         setAppText('C');
         React.startTransition(() => {
           setFallbackText('Still loading...');
@@ -3419,7 +3419,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
       // Mount an initial tree. Resolve A so that it doesn't suspend.
       await seedNextTextCache('A');
-      await act(async () => {
+      await act(() => {
         root.render(<Parent />);
       });
       assertLog(['A']);
@@ -3428,7 +3428,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
       // Schedule another update. This will "flip" the alternate pairs.
       await resolveText('B');
-      await act(async () => {
+      await act(() => {
         setText('B');
       });
       assertLog(['B']);
@@ -3436,7 +3436,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       expect(root).toMatchRenderedOutput(<span prop="B" />);
 
       // Schedule another update. This time, we'll suspend.
-      await act(async () => {
+      await act(() => {
         setText('C');
       });
       assertLog(['Suspend! [C]', 'Loading...']);
@@ -3458,7 +3458,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
       // Update again. This should unsuspend the tree.
       await resolveText('D');
-      await act(async () => {
+      await act(() => {
         setText('D');
       });
       // Even though the fragment fiber is not part of the return path, we should
@@ -3496,7 +3496,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
       // Mount an initial tree. Resolve A so that it doesn't suspend.
       await seedNextTextCache('A');
-      await act(async () => {
+      await act(() => {
         root.render(<Parent />);
       });
       assertLog(['A']);
@@ -3505,7 +3505,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
       // Schedule another update. This will "flip" the alternate pairs.
       await resolveText('B');
-      await act(async () => {
+      await act(() => {
         setText('B');
       });
       assertLog(['B']);
@@ -3513,7 +3513,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       expect(root).toMatchRenderedOutput(<span prop="B" />);
 
       // Schedule another update. This time, we'll suspend.
-      await act(async () => {
+      await act(() => {
         setText('C');
       });
       assertLog(['Suspend! [C]', 'Loading...']);
@@ -3603,7 +3603,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
       // Mount an initial tree. Resolve A so that it doesn't suspend.
       await seedNextTextCache('Inner text: A');
-      await act(async () => {
+      await act(() => {
         root.render(<Parent step={0} />);
       });
       assertLog([
@@ -3623,7 +3623,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       );
 
       // Update. This causes the inner component to suspend.
-      await act(async () => {
+      await act(() => {
         setText('B');
       });
       assertLog([
@@ -3646,7 +3646,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       );
 
       // Schedule a high pri update on the parent.
-      await act(async () => {
+      await act(() => {
         ReactNoop.discreteUpdates(() => {
           root.render(<Parent step={1} />);
         });
@@ -3736,7 +3736,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
     // Mount an initial tree. Resolve A so that it doesn't suspend.
     await seedNextTextCache('Inner: A0');
-    await act(async () => {
+    await act(() => {
       root.render(<Parent step={0} />);
     });
     assertLog(['Outer: A0', 'Inner: A0', 'Commit Child']);
@@ -3748,7 +3748,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
     );
 
     // Update. This causes the inner component to suspend.
-    await act(async () => {
+    await act(() => {
       setText('B');
     });
     assertLog(['Outer: B0', 'Suspend! [Inner: B0]', 'Loading...']);
@@ -3764,7 +3764,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
     // Schedule a high pri update on the parent. This will unblock the content.
     await resolveText('Inner: B1');
-    await act(async () => {
+    await act(() => {
       ReactNoop.discreteUpdates(() => {
         root.render(<Parent step={1} />);
       });
@@ -3825,7 +3825,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Root />);
     });
     assertLog(['']);
@@ -3944,7 +3944,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <UpdatingText />
@@ -4012,13 +4012,13 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
     const root = ReactNoop.createRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App show={false} />);
     });
     assertLog(['Mount Child']);
     expect(root).toMatchRenderedOutput(<span prop="Child" />);
 
-    await act(async () => {
+    await act(() => {
       root.render(<App show={true} />);
     });
     assertLog(['Suspend! [Async]', 'Loading...']);
@@ -4029,7 +4029,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
     assertLog(['Unmount Child']);
@@ -4060,13 +4060,13 @@ describe('ReactSuspenseWithNoopRenderer', () => {
 
     const root = ReactNoop.createLegacyRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App show={false} />);
     });
     assertLog(['Mount Child']);
     expect(root).toMatchRenderedOutput(<span prop="Child" />);
 
-    await act(async () => {
+    await act(() => {
       root.render(<App show={true} />);
     });
     assertLog(['Suspend! [Async]', 'Loading...']);
@@ -4077,7 +4077,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       </>,
     );
 
-    await act(async () => {
+    await act(() => {
       root.render(null);
     });
     assertLog(['Unmount Child']);
@@ -4127,7 +4127,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       // Initial render. This mounts a Suspense boundary, so that in the next
       // update we can trigger a "suspend with delay" scenario.
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(<App showMore={false} />);
       });
       assertLog([]);
@@ -4146,7 +4146,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
       //
       // The fix was to check if we're in the render phase before calling
       // `prepareFreshStack`.
-      await act(async () => {
+      await act(() => {
         root.render(<App showMore={true} />);
       });
       assertLog(['Suspend! [Async]', 'Loading...', 'Hi']);
diff --git a/packages/react-reconciler/src/__tests__/ReactThenable-test.js b/packages/react-reconciler/src/__tests__/ReactThenable-test.js
index 4b2eef866be50..5677396ae1370 100644
--- a/packages/react-reconciler/src/__tests__/ReactThenable-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactThenable-test.js
@@ -98,7 +98,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -133,7 +133,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -175,7 +175,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Suspend!', 'Loading...']);
@@ -202,7 +202,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -230,7 +230,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -276,7 +276,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -309,7 +309,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -345,7 +345,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -398,7 +398,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -523,7 +523,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
@@ -546,7 +546,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="Loading..." />}>
           <Text text="(empty)" />
@@ -556,7 +556,7 @@ describe('ReactThenable', () => {
     assertLog(['(empty)']);
     expect(root).toMatchRenderedOutput('(empty)');
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback={<Text text="Loading..." />}>
@@ -568,7 +568,7 @@ describe('ReactThenable', () => {
     assertLog(['Async text requested [Async]']);
     expect(root).toMatchRenderedOutput('(empty)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('Async');
     });
     assertLog(['Async text requested [Async]', 'Async']);
@@ -582,7 +582,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback={<Text text="Loading..." />}>
@@ -596,7 +596,7 @@ describe('ReactThenable', () => {
     expect(root).toMatchRenderedOutput('Loading...');
 
     // Resolve the original data
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('Async');
     });
     // During the retry, a fresh request is initiated. Now we must wait for this
@@ -610,7 +610,7 @@ describe('ReactThenable', () => {
     expect(root).toMatchRenderedOutput('Loading...');
 
     // Flush the second request.
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('Async');
     });
     // This time it finishes because it was during a retry.
@@ -625,11 +625,11 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Suspense fallback={<Text text="Loading..." />} />);
     });
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback={<Text text="Loading..." />}>
@@ -640,7 +640,7 @@ describe('ReactThenable', () => {
     });
     assertLog(['Async text requested [Will never resolve]']);
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="Loading..." />}>
           <Text text="Something different" />
@@ -659,12 +659,12 @@ describe('ReactThenable', () => {
     }
 
     const root1 = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root1.render(<Suspense fallback={<Text text="Loading..." />} />);
     });
 
     // Start a transition on one root. It will suspend.
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root1.render(
           <Suspense fallback={<Text text="Loading..." />}>
@@ -678,7 +678,7 @@ describe('ReactThenable', () => {
     // While we're waiting for the first root's data to resolve, a second
     // root renders.
     const root2 = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root2.render('Do re mi');
     });
     expect(root2).toMatchRenderedOutput('Do re mi');
@@ -698,11 +698,11 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Suspense fallback={<Text text="Loading..." />} />);
     });
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(
           <Suspense fallback={<Text text="Loading..." />}>
@@ -782,7 +782,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Parent />);
     });
     assertLog(['childShouldSuspend: false, showChild: true', 'Child']);
@@ -856,7 +856,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<ExcitingText text="Hello" />);
       });
@@ -866,7 +866,7 @@ describe('ReactThenable', () => {
     expect(root).toMatchRenderedOutput(null);
 
     // The data is received.
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('HELLO!');
     });
     assertLog([
@@ -894,42 +894,42 @@ describe('ReactThenable', () => {
 
     // Initial render.
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<Kitchen />);
       });
     });
     assertLog(['Async text requested [apple]']);
     expect(root).toMatchRenderedOutput(null);
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('apple');
     });
     assertLog(['Async text requested [apple]', 'apple carrot']);
     expect(root).toMatchRenderedOutput('apple carrot');
 
     // Update the state variable after the use().
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         _setVegetable('dill');
       });
     });
     assertLog(['Async text requested [apple]']);
     expect(root).toMatchRenderedOutput('apple carrot');
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('apple');
     });
     assertLog(['Async text requested [apple]', 'apple dill']);
     expect(root).toMatchRenderedOutput('apple dill');
 
     // Update the state variable before the use(). The second state is maintained.
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         _setFruit('banana');
       });
     });
     assertLog(['Async text requested [banana]']);
     expect(root).toMatchRenderedOutput('apple dill');
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('banana');
     });
     assertLog(['Async text requested [banana]', 'banana dill']);
@@ -949,28 +949,28 @@ describe('ReactThenable', () => {
 
     // Initial render.
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<Lexicon />);
       });
     });
     assertLog(['Async text requested [aguacate]']);
     expect(root).toMatchRenderedOutput(null);
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('aguacate');
     });
     assertLog(['Async text requested [aguacate]', 'aguacate abogado']);
     expect(root).toMatchRenderedOutput('aguacate abogado');
 
     // Now update the state.
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         _setLawyer('avocat');
       });
     });
     assertLog(['Async text requested [aguacate]']);
     expect(root).toMatchRenderedOutput('aguacate abogado');
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('aguacate');
     });
     assertLog(['Async text requested [aguacate]', 'aguacate avocat']);
@@ -989,7 +989,7 @@ describe('ReactThenable', () => {
       }
 
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           root.render(<App text="Hello" />);
         });
@@ -997,7 +997,7 @@ describe('ReactThenable', () => {
       assertLog(['Async text requested [Hello]']);
       expect(root).toMatchRenderedOutput(null);
 
-      await act(async () => {
+      await act(() => {
         resolveTextRequests('Hello');
       });
       assertLog([
@@ -1019,7 +1019,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="(Loading A...)" />}>
           <AsyncText text="A" />
@@ -1042,19 +1042,19 @@ describe('ReactThenable', () => {
     ]);
     expect(root).toMatchRenderedOutput('(Loading A...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('A');
     });
     assertLog(['A', '(Loading C...)', '(Loading B...)']);
     expect(root).toMatchRenderedOutput('A(Loading B...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('B');
     });
     assertLog(['B', '(Loading C...)']);
     expect(root).toMatchRenderedOutput('AB(Loading C...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('C');
     });
     assertLog(['C']);
@@ -1072,7 +1072,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<Text text="(Loading A...)" />}>
           <AsyncText text="A" />
@@ -1095,13 +1095,13 @@ describe('ReactThenable', () => {
     ]);
     expect(root).toMatchRenderedOutput('(Loading A...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('A');
     });
     assertLog(['Async text requested [A]']);
     expect(root).toMatchRenderedOutput('(Loading A...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('A');
     });
     assertLog([
@@ -1120,13 +1120,13 @@ describe('ReactThenable', () => {
     ]);
     expect(root).toMatchRenderedOutput('A(Loading B...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('B');
     });
     assertLog(['Async text requested [B]']);
     expect(root).toMatchRenderedOutput('A(Loading B...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('B');
     });
     assertLog([
@@ -1140,13 +1140,13 @@ describe('ReactThenable', () => {
     ]);
     expect(root).toMatchRenderedOutput('AB(Loading C...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('C');
     });
     assertLog(['Async text requested [C]']);
     expect(root).toMatchRenderedOutput('AB(Loading C...)');
 
-    await act(async () => {
+    await act(() => {
       resolveTextRequests('C');
     });
     assertLog(['Async text requested [C]', 'C']);
@@ -1174,7 +1174,7 @@ describe('ReactThenable', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       startTransition(() => {
         root.render(<App />);
       });
diff --git a/packages/react-reconciler/src/__tests__/ReactTransition-test.js b/packages/react-reconciler/src/__tests__/ReactTransition-test.js
index 54dabd07445f4..0f63ffe7a1f23 100644
--- a/packages/react-reconciler/src/__tests__/ReactTransition-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactTransition-test.js
@@ -185,7 +185,7 @@ describe('ReactTransition', () => {
 
     const root = ReactNoop.createRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['(empty)']);
@@ -245,7 +245,7 @@ describe('ReactTransition', () => {
 
       // Initial render
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         seedNextTextCache('A content');
         root.render(<App />);
       });
@@ -257,7 +257,7 @@ describe('ReactTransition', () => {
       );
 
       // Switch to B
-      await act(async () => {
+      await act(() => {
         update('B');
       });
       assertLog([
@@ -278,7 +278,7 @@ describe('ReactTransition', () => {
       );
 
       // Before B finishes loading, switch to C
-      await act(async () => {
+      await act(() => {
         update('C');
       });
       assertLog([
@@ -299,7 +299,7 @@ describe('ReactTransition', () => {
 
       // Finish loading B. But we're not allowed to render B because it's
       // entangled with C. So we're still pending.
-      await act(async () => {
+      await act(() => {
         resolveText('B content');
       });
       assertLog([
@@ -315,7 +315,7 @@ describe('ReactTransition', () => {
       );
 
       // Now finish loading C. This is the terminal update, so it can finish.
-      await act(async () => {
+      await act(() => {
         resolveText('C content');
       });
       assertLog(['C label', 'C content']);
@@ -370,7 +370,7 @@ describe('ReactTransition', () => {
 
       // Initial render
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         seedNextTextCache('A content');
         root.render(<App />);
       });
@@ -382,7 +382,7 @@ describe('ReactTransition', () => {
       );
 
       // Switch to B
-      await act(async () => {
+      await act(() => {
         update('B');
       });
       assertLog([
@@ -403,7 +403,7 @@ describe('ReactTransition', () => {
       );
 
       // Before B finishes loading, switch to C
-      await act(async () => {
+      await act(() => {
         update('C');
       });
       assertLog([
@@ -424,7 +424,7 @@ describe('ReactTransition', () => {
 
       // Finish loading B. But we're not allowed to render B because it's
       // entangled with C. So we're still pending.
-      await act(async () => {
+      await act(() => {
         resolveText('B content');
       });
       assertLog([
@@ -440,7 +440,7 @@ describe('ReactTransition', () => {
       );
 
       // Now finish loading C. This is the terminal update, so it can finish.
-      await act(async () => {
+      await act(() => {
         resolveText('C content');
       });
       assertLog(['C label', 'C content']);
@@ -488,14 +488,14 @@ describe('ReactTransition', () => {
 
       // Initial render. Start with all children hidden.
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(<App />);
       });
       assertLog([]);
       expect(root).toMatchRenderedOutput(null);
 
       // Switch to A.
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           setShowA(true);
         });
@@ -504,7 +504,7 @@ describe('ReactTransition', () => {
       expect(root).toMatchRenderedOutput(null);
 
       // Before A loads, switch to B. This should entangle A with B.
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           setShowA(false);
           setShowB(true);
@@ -515,7 +515,7 @@ describe('ReactTransition', () => {
 
       // Before A or B loads, switch to C. This should entangle C with B, and
       // transitively entangle C with A.
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           setShowB(false);
           setShowC(true);
@@ -528,7 +528,7 @@ describe('ReactTransition', () => {
 
       // First resolve B. This will attempt to render C, since everything is
       // entangled.
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           resolveText('B');
         });
@@ -538,7 +538,7 @@ describe('ReactTransition', () => {
 
       // Now resolve A. Again, this will attempt to render C, since everything
       // is entangled.
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           resolveText('A');
         });
@@ -547,7 +547,7 @@ describe('ReactTransition', () => {
       expect(root).toMatchRenderedOutput(null);
 
       // Finally, resolve C. This time we can finish.
-      await act(async () => {
+      await act(() => {
         startTransition(() => {
           resolveText('C');
         });
@@ -561,7 +561,7 @@ describe('ReactTransition', () => {
   test('interrupt a refresh transition if a new transition is scheduled', async () => {
     const root = ReactNoop.createRoot();
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <>
           <Suspense fallback={<Text text="Loading..." />} />
@@ -729,7 +729,7 @@ describe('ReactTransition', () => {
 
       const root = ReactNoop.createRoot();
 
-      await act(async () => {
+      await act(() => {
         root.render(<App shouldSuspend={false} step={0} />);
       });
       assertLog(['A0', 'B0', 'C0']);
@@ -793,7 +793,7 @@ describe('ReactTransition', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
 
@@ -801,7 +801,7 @@ describe('ReactTransition', () => {
     assertLog(['Transition pri: 0', 'Normal pri: 0', 'Commit']);
     expect(root).toMatchRenderedOutput('Transition pri: 0, Normal pri: 0');
 
-    await act(async () => {
+    await act(() => {
       updateTransitionPri();
       updateNormalPri();
     });
@@ -845,7 +845,7 @@ describe('ReactTransition', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
 
@@ -853,7 +853,7 @@ describe('ReactTransition', () => {
     assertLog(['(empty)', 'Normal pri: 0', 'Commit']);
     expect(root).toMatchRenderedOutput('(empty), Normal pri: 0');
 
-    await act(async () => {
+    await act(() => {
       updateTransitionPri();
     });
 
@@ -907,7 +907,7 @@ describe('ReactTransition', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['Transition pri: 0', 'Normal pri: 0', 'Commit']);
diff --git a/packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js b/packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js
index 658775a7be915..ebada20e879ae 100644
--- a/packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactTransitionTracing-test.js
@@ -2208,7 +2208,7 @@ describe('ReactInteractionTracing', () => {
     const root = ReactNoop.createRoot({
       unstable_transitionCallbacks: transitionCallbacks,
     });
-    await act(async () => {
+    await act(() => {
       startTransition(() => root.render(<App />), {name: 'transition'});
       ReactNoop.expire(1000);
       advanceTimers(1000);
@@ -2221,7 +2221,7 @@ describe('ReactInteractionTracing', () => {
       'onTransitionStart(transition, 0)',
     ]);
 
-    await act(async () => {
+    await act(() => {
       resolveText('Text');
       ReactNoop.expire(1000);
       advanceTimers(1000);
@@ -2232,7 +2232,7 @@ describe('ReactInteractionTracing', () => {
       'onTransitionComplete(transition, 0, 2000)',
     ]);
 
-    await act(async () => {
+    await act(() => {
       resolveText('Hidden Text');
       ReactNoop.expire(1000);
       advanceTimers(1000);
@@ -2343,7 +2343,7 @@ describe('ReactInteractionTracing', () => {
       unstable_transitionCallbacks: transitionCallbacks,
     });
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => root.render(<App />), {name: 'transition'});
       ReactNoop.expire(1000);
       advanceTimers(1000);
@@ -2361,7 +2361,7 @@ describe('ReactInteractionTracing', () => {
       'onTransitionProgress(transition, 0, 1000, [two])',
     ]);
 
-    await act(async () => {
+    await act(() => {
       resolveText('Text Two');
       ReactNoop.expire(1000);
       advanceTimers(1000);
@@ -2416,7 +2416,7 @@ describe('ReactInteractionTracing', () => {
       unstable_transitionCallbacks: getTransitionCallbacks('root two'),
     });
 
-    await act(async () => {
+    await act(() => {
       startTransition(() => rootOne.render(<App name="one" />), {
         name: 'transition one',
       });
@@ -2438,7 +2438,7 @@ describe('ReactInteractionTracing', () => {
       'onTransitionProgress(transition two, 0, 1000, [two]) /root two/',
     ]);
 
-    await act(async () => {
+    await act(() => {
       caches[0].resolve('Text one');
       ReactNoop.expire(1000);
       advanceTimers(1000);
@@ -2450,7 +2450,7 @@ describe('ReactInteractionTracing', () => {
       'onTransitionComplete(transition one, 0, 2000) /root one/',
     ]);
 
-    await act(async () => {
+    await act(() => {
       resolveText('Text two');
       ReactNoop.expire(1000);
       advanceTimers(1000);
diff --git a/packages/react-reconciler/src/__tests__/ReactUpdatePriority-test.js b/packages/react-reconciler/src/__tests__/ReactUpdatePriority-test.js
index 82314744eb706..c5de798366334 100644
--- a/packages/react-reconciler/src/__tests__/ReactUpdatePriority-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactUpdatePriority-test.js
@@ -46,7 +46,7 @@ describe('ReactUpdatePriority', () => {
       return <Text text={state} />;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.flushSync(() => {
         root.render(<App />);
       });
@@ -116,7 +116,7 @@ describe('ReactUpdatePriority', () => {
       );
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['A1', 'B1', 'C1']);
diff --git a/packages/react-reconciler/src/__tests__/ReactUpdaters-test.internal.js b/packages/react-reconciler/src/__tests__/ReactUpdaters-test.internal.js
index da02d0b208663..93e1d6937764d 100644
--- a/packages/react-reconciler/src/__tests__/ReactUpdaters-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/ReactUpdaters-test.internal.js
@@ -108,12 +108,12 @@ describe('updaters', () => {
     const Child = () => null;
     const container = document.createElement('div');
 
-    await act(async () => {
+    await act(() => {
       ReactDOM.render(<Parent />, container);
     });
     expect(allSchedulerTags).toEqual([[HostRoot]]);
 
-    await act(async () => {
+    await act(() => {
       ReactDOM.render(<Parent />, container);
     });
     expect(allSchedulerTags).toEqual([[HostRoot], [HostRoot]]);
@@ -141,19 +141,19 @@ describe('updaters', () => {
     };
     const Child = () => null;
 
-    await act(async () => {
+    await act(() => {
       ReactDOM.render(<Parent />, document.createElement('div'));
     });
     expect(scheduleForA).not.toBeNull();
     expect(scheduleForB).not.toBeNull();
     expect(allSchedulerTypes).toEqual([[null]]);
 
-    await act(async () => {
+    await act(() => {
       scheduleForA();
     });
     expect(allSchedulerTypes).toEqual([[null], [SchedulingComponentA]]);
 
-    await act(async () => {
+    await act(() => {
       scheduleForB();
     });
     expect(allSchedulerTypes).toEqual([
@@ -174,13 +174,13 @@ describe('updaters', () => {
     }
     const Child = () => null;
     let instance;
-    await act(async () => {
+    await act(() => {
       ReactDOM.render(<Parent />, document.createElement('div'));
     });
     expect(allSchedulerTypes).toEqual([[null]]);
 
     expect(instance).not.toBeNull();
-    await act(async () => {
+    await act(() => {
       instance.setState({});
     });
     expect(allSchedulerTypes).toEqual([[null], [SchedulingComponent]]);
@@ -294,21 +294,21 @@ describe('updaters', () => {
       }
     };
 
-    await act(async () => {
+    await act(() => {
       ReactDOM.render(<Parent />, document.createElement('div'));
       assertLog(['onCommitRoot']);
     });
     expect(setShouldSuspend).not.toBeNull();
     expect(allSchedulerTypes).toEqual([[null]]);
 
-    await act(async () => {
+    await act(() => {
       setShouldSuspend(true);
     });
     assertLog(['onCommitRoot']);
     expect(allSchedulerTypes).toEqual([[null], [Suspender]]);
 
     expect(resolver).not.toBeNull();
-    await act(async () => {
+    await act(() => {
       resolver('abc');
       return promise;
     });
@@ -356,7 +356,7 @@ describe('updaters', () => {
     };
 
     const root = ReactDOMClient.createRoot(document.createElement('div'));
-    await act(async () => {
+    await act(() => {
       root.render(<Parent shouldError={false} />);
     });
     assertLog(['initial', 'onCommitRoot']);
@@ -365,7 +365,7 @@ describe('updaters', () => {
     allSchedulerTypes.splice(0);
     onCommitRootShouldYield = true;
 
-    await act(async () => {
+    await act(() => {
       triggerError();
     });
     assertLog(['onCommitRoot', 'error', 'onCommitRoot']);
diff --git a/packages/react-reconciler/src/__tests__/StrictEffectsMode-test.js b/packages/react-reconciler/src/__tests__/StrictEffectsMode-test.js
index da230678ec65f..d7e5e29b0e7d6 100644
--- a/packages/react-reconciler/src/__tests__/StrictEffectsMode-test.js
+++ b/packages/react-reconciler/src/__tests__/StrictEffectsMode-test.js
@@ -51,7 +51,7 @@ describe('StrictEffectsMode', () => {
       return text;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<App text={'mount'} />);
     });
 
@@ -74,7 +74,7 @@ describe('StrictEffectsMode', () => {
     }
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<App text={'mount'} />, {
         unstable_isConcurrent: true,
       });
@@ -93,7 +93,7 @@ describe('StrictEffectsMode', () => {
       assertLog(['useLayoutEffect mount', 'useEffect mount']);
     }
 
-    await act(async () => {
+    await act(() => {
       renderer.update(<App text={'update'} />);
     });
 
@@ -104,7 +104,7 @@ describe('StrictEffectsMode', () => {
       'useEffect mount',
     ]);
 
-    await act(async () => {
+    await act(() => {
       renderer.unmount();
     });
 
@@ -127,7 +127,7 @@ describe('StrictEffectsMode', () => {
     }
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<App text={'mount'} />, {
         unstable_isConcurrent: true,
       });
@@ -146,7 +146,7 @@ describe('StrictEffectsMode', () => {
       assertLog(['useEffect One mount', 'useEffect Two mount']);
     }
 
-    await act(async () => {
+    await act(() => {
       renderer.update(<App text={'update'} />);
     });
 
@@ -157,7 +157,7 @@ describe('StrictEffectsMode', () => {
       'useEffect Two mount',
     ]);
 
-    await act(async () => {
+    await act(() => {
       renderer.unmount(null);
     });
 
@@ -180,7 +180,7 @@ describe('StrictEffectsMode', () => {
     }
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<App text={'mount'} />, {
         unstable_isConcurrent: true,
       });
@@ -199,7 +199,7 @@ describe('StrictEffectsMode', () => {
       assertLog(['useLayoutEffect One mount', 'useLayoutEffect Two mount']);
     }
 
-    await act(async () => {
+    await act(() => {
       renderer.update(<App text={'update'} />);
     });
 
@@ -210,7 +210,7 @@ describe('StrictEffectsMode', () => {
       'useLayoutEffect Two mount',
     ]);
 
-    await act(async () => {
+    await act(() => {
       renderer.unmount();
     });
 
@@ -231,7 +231,7 @@ describe('StrictEffectsMode', () => {
     }
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<App text={'mount'} />, {
         unstable_isConcurrent: true,
       });
@@ -248,13 +248,13 @@ describe('StrictEffectsMode', () => {
       assertLog(['useLayoutEffect mount', 'useEffect mount']);
     }
 
-    await act(async () => {
+    await act(() => {
       renderer.update(<App text={'update'} />);
     });
 
     assertLog(['useLayoutEffect mount', 'useEffect mount']);
 
-    await act(async () => {
+    await act(() => {
       renderer.unmount();
     });
 
@@ -285,7 +285,7 @@ describe('StrictEffectsMode', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<App />, {unstable_isConcurrent: true});
     });
 
@@ -320,7 +320,7 @@ describe('StrictEffectsMode', () => {
     }
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<App text={'mount'} />, {
         unstable_isConcurrent: true,
       });
@@ -336,13 +336,13 @@ describe('StrictEffectsMode', () => {
       assertLog(['componentDidMount']);
     }
 
-    await act(async () => {
+    await act(() => {
       renderer.update(<App text={'update'} />);
     });
 
     assertLog(['componentDidUpdate']);
 
-    await act(async () => {
+    await act(() => {
       renderer.unmount();
     });
 
@@ -368,7 +368,7 @@ describe('StrictEffectsMode', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<App text={'mount'} />);
     });
 
@@ -395,7 +395,7 @@ describe('StrictEffectsMode', () => {
       return text;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<App text={'mount'} />, {
         unstable_isConcurrent: true,
       });
@@ -460,7 +460,7 @@ describe('StrictEffectsMode', () => {
       return showChild && <Child />;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<App />, {unstable_isConcurrent: true});
     });
 
@@ -477,7 +477,7 @@ describe('StrictEffectsMode', () => {
       assertLog(['App useLayoutEffect mount', 'App useEffect mount']);
     }
 
-    await act(async () => {
+    await act(() => {
       _setShowChild(true);
     });
 
@@ -543,7 +543,7 @@ describe('StrictEffectsMode', () => {
     }
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<App text={'mount'} />, {
         unstable_isConcurrent: true,
       });
@@ -569,7 +569,7 @@ describe('StrictEffectsMode', () => {
       ]);
     }
 
-    await act(async () => {
+    await act(() => {
       renderer.update(<App text={'mount'} />);
     });
 
@@ -580,7 +580,7 @@ describe('StrictEffectsMode', () => {
       'useEffect mount',
     ]);
 
-    await act(async () => {
+    await act(() => {
       renderer.unmount();
     });
 
diff --git a/packages/react-reconciler/src/__tests__/StrictEffectsModeDefaults-test.internal.js b/packages/react-reconciler/src/__tests__/StrictEffectsModeDefaults-test.internal.js
index b1ceb8ed7e247..fa72a610ab9a8 100644
--- a/packages/react-reconciler/src/__tests__/StrictEffectsModeDefaults-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/StrictEffectsModeDefaults-test.internal.js
@@ -52,7 +52,7 @@ describe('StrictEffectsMode defaults', () => {
       return text;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.renderLegacySyncRoot(<App text={'mount'} />);
     });
 
@@ -78,7 +78,7 @@ describe('StrictEffectsMode defaults', () => {
       }
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.renderLegacySyncRoot(<App text={'mount'} />);
     });
 
@@ -208,7 +208,7 @@ describe('StrictEffectsMode defaults', () => {
 
         return text;
       }
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -221,7 +221,7 @@ describe('StrictEffectsMode defaults', () => {
         'useEffect mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'update'} />);
       });
 
@@ -232,7 +232,7 @@ describe('StrictEffectsMode defaults', () => {
         'useEffect mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
 
@@ -254,7 +254,7 @@ describe('StrictEffectsMode defaults', () => {
         return text;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -267,7 +267,7 @@ describe('StrictEffectsMode defaults', () => {
         'useEffect Two mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'update'} />);
       });
 
@@ -278,7 +278,7 @@ describe('StrictEffectsMode defaults', () => {
         'useEffect Two mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
 
@@ -300,7 +300,7 @@ describe('StrictEffectsMode defaults', () => {
         return text;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -313,7 +313,7 @@ describe('StrictEffectsMode defaults', () => {
         'useLayoutEffect Two mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'update'} />);
       });
 
@@ -324,7 +324,7 @@ describe('StrictEffectsMode defaults', () => {
         'useLayoutEffect Two mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
 
@@ -344,7 +344,7 @@ describe('StrictEffectsMode defaults', () => {
         return text;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -355,13 +355,13 @@ describe('StrictEffectsMode defaults', () => {
         'useEffect mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'update'} />);
       });
 
       assertLog(['useLayoutEffect mount', 'useEffect mount']);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
 
@@ -382,7 +382,7 @@ describe('StrictEffectsMode defaults', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -416,7 +416,7 @@ describe('StrictEffectsMode defaults', () => {
         }
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
 
@@ -446,7 +446,7 @@ describe('StrictEffectsMode defaults', () => {
         }
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -456,13 +456,13 @@ describe('StrictEffectsMode defaults', () => {
         'componentDidMount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'update'} />);
       });
 
       assertLog(['componentDidUpdate']);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
 
@@ -489,7 +489,7 @@ describe('StrictEffectsMode defaults', () => {
         return text;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -539,7 +539,7 @@ describe('StrictEffectsMode defaults', () => {
         return showChild && <Child />;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App />);
       });
 
@@ -552,7 +552,7 @@ describe('StrictEffectsMode defaults', () => {
         'App useEffect mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         _setShowChild(true);
       });
 
@@ -606,7 +606,7 @@ describe('StrictEffectsMode defaults', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -622,7 +622,7 @@ describe('StrictEffectsMode defaults', () => {
         'useEffect mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<App text={'mount'} />);
       });
 
@@ -633,7 +633,7 @@ describe('StrictEffectsMode defaults', () => {
         'useEffect mount',
       ]);
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(null);
       });
 
diff --git a/packages/react-reconciler/src/__tests__/useEffectEvent-test.js b/packages/react-reconciler/src/__tests__/useEffectEvent-test.js
index a2bfbb67ed076..217d88a90298b 100644
--- a/packages/react-reconciler/src/__tests__/useEffectEvent-test.js
+++ b/packages/react-reconciler/src/__tests__/useEffectEvent-test.js
@@ -88,7 +88,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog(['Increment', 'Count: 1']);
     expect(ReactNoop).toMatchRenderedOutput(
       <>
@@ -97,7 +97,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog([
       'Increment',
       // Event should use the updated callback function closed over the new value.
@@ -121,7 +121,7 @@ describe('useEffectEvent', () => {
     );
 
     // Event uses the new prop
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog(['Increment', 'Count: 12']);
     expect(ReactNoop).toMatchRenderedOutput(
       <>
@@ -174,7 +174,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog(['Increment', 'Count: 5']);
     expect(ReactNoop).toMatchRenderedOutput(
       <>
@@ -183,7 +183,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.multiply());
+    await act(() => button.current.multiply());
     assertLog(['Increment', 'Count: 25']);
     expect(ReactNoop).toMatchRenderedOutput(
       <>
@@ -233,7 +233,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.greet());
+    await act(() => button.current.greet());
     assertLog(['Say hej', 'Greeting: undefined says hej']);
     expect(ReactNoop).toMatchRenderedOutput(
       <>
@@ -327,7 +327,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog([
       'Increment',
       // Effect should not re-run because the dependency hasn't changed.
@@ -340,7 +340,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog([
       'Increment',
       // Event should use the updated callback function closed over the new value.
@@ -370,7 +370,7 @@ describe('useEffectEvent', () => {
     );
 
     // Event uses the new prop
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog(['Increment', 'Count: 34']);
     expect(ReactNoop).toMatchRenderedOutput(
       <>
@@ -426,7 +426,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog([
       'Increment',
       // Effect should not re-run because the dependency hasn't changed.
@@ -439,7 +439,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog([
       'Increment',
       // Event should use the updated callback function closed over the new value.
@@ -469,7 +469,7 @@ describe('useEffectEvent', () => {
     );
 
     // Event uses the new prop
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog(['Increment', 'Count: 34']);
     expect(ReactNoop).toMatchRenderedOutput(
       <>
@@ -531,7 +531,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog([
       'Increment',
       // Effect should not re-run because the dependency hasn't changed.
@@ -544,7 +544,7 @@ describe('useEffectEvent', () => {
       </>,
     );
 
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog([
       'Increment',
       // Event should use the updated callback function closed over the new value.
@@ -574,7 +574,7 @@ describe('useEffectEvent', () => {
     );
 
     // Event uses the new prop
-    await act(async () => button.current.increment());
+    await act(() => button.current.increment());
     assertLog(['Increment', 'Count: 34']);
     expect(ReactNoop).toMatchRenderedOutput(
       <>
@@ -604,7 +604,7 @@ describe('useEffectEvent', () => {
     ReactNoop.render(<Counter value={1} />);
     await waitForAll(['Effect value: 1', 'Event value: 1']);
 
-    await act(async () => ReactNoop.render(<Counter value={2} />));
+    await act(() => ReactNoop.render(<Counter value={2} />));
     assertLog(['Effect value: 2', 'Event value: 2']);
   });
 
@@ -678,7 +678,7 @@ describe('useEffectEvent', () => {
 
     // Initial render
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App value={1} />);
     });
     assertLog(['Commit new event handler']);
@@ -686,7 +686,7 @@ describe('useEffectEvent', () => {
     expect(committedEventHandler()).toBe('Value seen by useEffectEvent: 1');
 
     // Update
-    await act(async () => {
+    await act(() => {
       root.render(<App value={2} />);
     });
     // No new event handler should be committed, because it was omitted from
@@ -742,20 +742,20 @@ describe('useEffectEvent', () => {
       return <Text text={`Welcome to the ${roomId} room!`} />;
     }
 
-    await act(async () =>
+    await act(() =>
       ReactNoop.render(<ChatRoom roomId="general" theme="light" />),
     );
-    await act(async () => jest.runAllTimers());
+    await act(() => jest.runAllTimers());
     assertLog(['Welcome to the general room!', 'Connected! theme: light']);
     expect(ReactNoop).toMatchRenderedOutput(
       <span prop="Welcome to the general room!" />,
     );
 
     // change roomId only
-    await act(async () =>
+    await act(() =>
       ReactNoop.render(<ChatRoom roomId="music" theme="light" />),
     );
-    await act(async () => jest.runAllTimers());
+    await act(() => jest.runAllTimers());
     assertLog([
       'Welcome to the music room!',
       // should trigger a reconnect
@@ -767,10 +767,8 @@ describe('useEffectEvent', () => {
     );
 
     // change theme only
-    await act(async () =>
-      ReactNoop.render(<ChatRoom roomId="music" theme="dark" />),
-    );
-    await act(async () => jest.runAllTimers());
+    await act(() => ReactNoop.render(<ChatRoom roomId="music" theme="dark" />));
+    await act(() => jest.runAllTimers());
     // should not trigger a reconnect
     assertLog(['Welcome to the music room!']);
     expect(ReactNoop).toMatchRenderedOutput(
@@ -778,10 +776,10 @@ describe('useEffectEvent', () => {
     );
 
     // change roomId only
-    await act(async () =>
+    await act(() =>
       ReactNoop.render(<ChatRoom roomId="travel" theme="dark" />),
     );
-    await act(async () => jest.runAllTimers());
+    await act(() => jest.runAllTimers());
     assertLog([
       'Welcome to the travel room!',
       // should trigger a reconnect
@@ -841,7 +839,7 @@ describe('useEffectEvent', () => {
     }
 
     const button = React.createRef(null);
-    await act(async () =>
+    await act(() =>
       ReactNoop.render(
         <AppShell>
           <Page url="/shop/1" />
@@ -849,10 +847,10 @@ describe('useEffectEvent', () => {
       ),
     );
     assertLog(['Add to cart', 'url: /shop/1, numberOfItems: 0']);
-    await act(async () => button.current.addToCart());
+    await act(() => button.current.addToCart());
     assertLog(['Add to cart']);
 
-    await act(async () =>
+    await act(() =>
       ReactNoop.render(
         <AppShell>
           <Page url="/shop/2" />
diff --git a/packages/react-reconciler/src/__tests__/useMemoCache-test.js b/packages/react-reconciler/src/__tests__/useMemoCache-test.js
index 0d08481d3618c..7dd58514bea67 100644
--- a/packages/react-reconciler/src/__tests__/useMemoCache-test.js
+++ b/packages/react-reconciler/src/__tests__/useMemoCache-test.js
@@ -63,7 +63,7 @@ describe('useMemoCache()', () => {
       return 'Ok';
     }
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Component />);
     });
     expect(root).toMatchRenderedOutput('Ok');
@@ -107,7 +107,7 @@ describe('useMemoCache()', () => {
     });
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Component />);
     });
     expect(root).toMatchRenderedOutput('Count 0');
@@ -115,7 +115,7 @@ describe('useMemoCache()', () => {
     const data0 = data;
 
     // Changing x should reset the data object
-    await act(async () => {
+    await act(() => {
       setX(1);
     });
     expect(root).toMatchRenderedOutput('Count 1');
@@ -125,7 +125,7 @@ describe('useMemoCache()', () => {
 
     // Forcing an unrelated update shouldn't recreate the
     // data object.
-    await act(async () => {
+    await act(() => {
       forceUpdate();
     });
     expect(root).toMatchRenderedOutput('Count 1');
@@ -183,7 +183,7 @@ describe('useMemoCache()', () => {
     });
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Component />);
     });
     expect(root).toMatchRenderedOutput('Count 0');
@@ -193,7 +193,7 @@ describe('useMemoCache()', () => {
     // Simultaneously trigger an update to x (should create a new data value)
     // and trigger the setState+early return. The runtime should reset the cache
     // to avoid an inconsistency
-    await act(async () => {
+    await act(() => {
       setX(1);
       setN(1);
     });
@@ -204,7 +204,7 @@ describe('useMemoCache()', () => {
 
     // Forcing an unrelated update shouldn't recreate the
     // data object.
-    await act(async () => {
+    await act(() => {
       setN(3);
     });
     expect(root).toMatchRenderedOutput('Count 1');
@@ -266,7 +266,7 @@ describe('useMemoCache()', () => {
     spyOnDev(console, 'error');
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <ErrorBoundary>
           <Component />
@@ -280,7 +280,7 @@ describe('useMemoCache()', () => {
     // Simultaneously trigger an update to x (should create a new data value)
     // and trigger the setState+early return. The runtime should reset the cache
     // to avoid an inconsistency
-    await act(async () => {
+    await act(() => {
       // this update bumps the count
       setX(1);
       // this triggers a throw.
@@ -293,7 +293,7 @@ describe('useMemoCache()', () => {
 
     // Forcing an unrelated update shouldn't recreate the
     // data object.
-    await act(async () => {
+    await act(() => {
       setN(3);
     });
     expect(root).toMatchRenderedOutput('Count 1');
@@ -352,7 +352,7 @@ describe('useMemoCache()', () => {
     });
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<Component />);
     });
     expect(root).toMatchRenderedOutput('count 0');
@@ -360,7 +360,7 @@ describe('useMemoCache()', () => {
     const data0 = data;
 
     // Changing x should reset the data object
-    await act(async () => {
+    await act(() => {
       setX(1);
     });
     expect(root).toMatchRenderedOutput('count 1');
@@ -370,7 +370,7 @@ describe('useMemoCache()', () => {
 
     // Forcing an unrelated update shouldn't recreate the
     // data object.
-    await act(async () => {
+    await act(() => {
       forceUpdate();
     });
     expect(root).toMatchRenderedOutput('count 1');
diff --git a/packages/react-reconciler/src/__tests__/useMutableSource-test.internal.js b/packages/react-reconciler/src/__tests__/useMutableSource-test.internal.js
index a85a41b9afb60..9c7365f6216d9 100644
--- a/packages/react-reconciler/src/__tests__/useMutableSource-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/useMutableSource-test.internal.js
@@ -1060,18 +1060,18 @@ describe('useMutableSource', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App getSnapshot={getSnapshotA} />);
     });
     expect(root).toMatchRenderedOutput('initial');
 
-    await act(async () => {
+    await act(() => {
       mutateB('Updated B');
       root.render(<App getSnapshot={getSnapshotB} />);
     });
     expect(root).toMatchRenderedOutput('Updated B');
 
-    await act(async () => {
+    await act(() => {
       mutateB('Another update');
     });
     expect(root).toMatchRenderedOutput('Another update');
@@ -1113,12 +1113,12 @@ describe('useMutableSource', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App toggle={false} />);
     });
     expect(root).toMatchRenderedOutput('A: initial');
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.discreteUpdates(() => {
         // Update both A and B to the same value
         mutateA('Update');
@@ -1158,12 +1158,12 @@ describe('useMutableSource', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App toggle={false} />);
     });
     expect(root).toMatchRenderedOutput('A: initial');
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.discreteUpdates(() => {
         // Update both A and B to the same value
         sourceA.value = 'Update';
@@ -1227,7 +1227,7 @@ describe('useMutableSource', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <App
           getSnapshotFirst={getSnapshotA}
@@ -1238,7 +1238,7 @@ describe('useMutableSource', () => {
     // x and y start out reading from different parts of the store.
     assertLog(['x: foo, y: bar']);
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.discreteUpdates(() => {
         // At high priority, toggle y so that it reads from A instead of B.
         // Simultaneously, mutate A.
@@ -1303,7 +1303,7 @@ describe('useMutableSource', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App getSnapshot={getSnapshotA} />);
     });
     assertLog(['Render: foo', 'Commit: foo']);
@@ -1362,7 +1362,7 @@ describe('useMutableSource', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(
         <App
           getSnapshotFirst={getSnapshotA}
@@ -1387,7 +1387,7 @@ describe('useMutableSource', () => {
       // Now mutate A. Both hooks should update.
       // This is at high priority so that it doesn't get batched with default
       // priority updates that might fire during the passive effect
-      await act(async () => {
+      await act(() => {
         ReactNoop.discreteUpdates(() => {
           mutateA('a1');
         });
@@ -1444,7 +1444,7 @@ describe('useMutableSource', () => {
       }
 
       const root = ReactNoop.createRoot();
-      await act(async () => {
+      await act(() => {
         root.render(
           <>
             <Read getSnapshot={getSnapshotA} />
@@ -1590,7 +1590,7 @@ describe('useMutableSource', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App parentConfig={configA} childConfig={configB} />);
     });
     assertLog(['Parent: 1', 'Child: 2', 'Commit: 1, 2']);
@@ -1666,7 +1666,7 @@ describe('useMutableSource', () => {
     }
 
     // Mount ComponentA with data version 1
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler id="root" onRender={onRender}>
           <ComponentA />
@@ -1713,7 +1713,7 @@ describe('useMutableSource', () => {
         const brokenSubscribe = () => {};
 
         await expect(async () => {
-          await act(async () => {
+          await act(() => {
             ReactNoop.render(
               <Component
                 label="only"
diff --git a/packages/react-reconciler/src/__tests__/useMutableSourceHydration-test.js b/packages/react-reconciler/src/__tests__/useMutableSourceHydration-test.js
index 96eef57c9484e..f8f77a27f141e 100644
--- a/packages/react-reconciler/src/__tests__/useMutableSourceHydration-test.js
+++ b/packages/react-reconciler/src/__tests__/useMutableSourceHydration-test.js
@@ -165,7 +165,7 @@ describe('useMutableSourceHydration', () => {
     assertLog(['only:one']);
     expect(source.listenerCount).toBe(0);
 
-    await act(async () => {
+    await act(() => {
       ReactDOMClient.hydrateRoot(container, <TestComponent />, {
         mutableSources: [mutableSource],
       });
@@ -200,7 +200,7 @@ describe('useMutableSourceHydration', () => {
     expect(source.listenerCount).toBe(0);
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         ReactDOMClient.hydrateRoot(container, <TestComponent />, {
           mutableSources: [mutableSource],
           onRecoverableError(error) {
diff --git a/packages/react-reconciler/src/__tests__/useRef-test.internal.js b/packages/react-reconciler/src/__tests__/useRef-test.internal.js
index 1acac1a5bbc9c..9c918b961ad31 100644
--- a/packages/react-reconciler/src/__tests__/useRef-test.internal.js
+++ b/packages/react-reconciler/src/__tests__/useRef-test.internal.js
@@ -82,7 +82,7 @@ describe('useRef', () => {
       return null;
     }
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(<App />);
     });
     assertLog([]);
@@ -152,10 +152,10 @@ describe('useRef', () => {
         );
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example phase="mount" />);
       });
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example phase="update" />);
       });
     });
@@ -173,7 +173,7 @@ describe('useRef', () => {
         return value;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
     });
@@ -192,12 +192,12 @@ describe('useRef', () => {
         return null;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
 
       // Should not warn after an update either.
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
     });
@@ -216,7 +216,7 @@ describe('useRef', () => {
         return null;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
     });
@@ -251,13 +251,13 @@ describe('useRef', () => {
       }
 
       let shouldExpectWarning = true;
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
 
       // Should not warn again on update.
       shouldExpectWarning = false;
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
     });
@@ -291,7 +291,7 @@ describe('useRef', () => {
         return value;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
     });
@@ -323,7 +323,7 @@ describe('useRef', () => {
         return null;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
     });
@@ -344,7 +344,7 @@ describe('useRef', () => {
         return null;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
 
@@ -358,7 +358,7 @@ describe('useRef', () => {
         return null;
       }
 
-      await act(async () => {
+      await act(() => {
         ReactNoop.render(<Example />);
       });
 
diff --git a/packages/react-reconciler/src/__tests__/useSyncExternalStore-test.js b/packages/react-reconciler/src/__tests__/useSyncExternalStore-test.js
index 64e5a102a21bb..d620cd7ed8b0e 100644
--- a/packages/react-reconciler/src/__tests__/useSyncExternalStore-test.js
+++ b/packages/react-reconciler/src/__tests__/useSyncExternalStore-test.js
@@ -195,19 +195,19 @@ describe('useSyncExternalStore', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       // Start a render that reads from the store and yields value
       root.render(<App />);
     });
     assertLog(['value:initial']);
 
-    await act(async () => {
+    await act(() => {
       store.set('value:changed');
     });
     assertLog(['value:changed']);
 
     // If cached value was updated, we expect a re-render
-    await act(async () => {
+    await act(() => {
       store.set('value:initial');
     });
     assertLog(['value:initial']);
diff --git a/packages/react-refresh/src/__tests__/ReactFresh-test.js b/packages/react-refresh/src/__tests__/ReactFresh-test.js
index cdb5c2eaa90a8..aa7b2504227e0 100644
--- a/packages/react-refresh/src/__tests__/ReactFresh-test.js
+++ b/packages/react-refresh/src/__tests__/ReactFresh-test.js
@@ -864,7 +864,7 @@ describe('ReactFresh', () => {
       });
 
       expect(container.textContent).toBe('Loading');
-      await act(async () => {
+      await act(() => {
         jest.runAllTimers();
       });
       expect(container.textContent).toBe('0');
@@ -1013,7 +1013,7 @@ describe('ReactFresh', () => {
         $RefreshReg$(Hello, 'Hello');
       });
 
-      await act(async () => {
+      await act(() => {
         jest.runAllTimers();
       });
 
@@ -1097,7 +1097,7 @@ describe('ReactFresh', () => {
         $RefreshReg$(Hello, 'Hello');
       });
 
-      await act(async () => {
+      await act(() => {
         jest.runAllTimers();
       });
 
@@ -1182,7 +1182,7 @@ describe('ReactFresh', () => {
         $RefreshReg$(Hello, 'Hello');
       });
 
-      await act(async () => {
+      await act(() => {
         jest.runAllTimers();
       });
 
@@ -1267,7 +1267,7 @@ describe('ReactFresh', () => {
         $RefreshReg$(Hello, 'Hello');
       });
 
-      await act(async () => {
+      await act(() => {
         jest.runAllTimers();
       });
 
@@ -2482,7 +2482,7 @@ describe('ReactFresh', () => {
     expect(el.firstChild.textContent).toBe('0');
     expect(el.firstChild.style.color).toBe('red');
 
-    await internalAct(async () => {
+    await internalAct(() => {
       el.firstChild.dispatchEvent(
         new MouseEvent('click', {
           bubbles: true,
diff --git a/packages/react-server-dom-relay/src/__tests__/ReactFlightDOMRelay-test.internal.js b/packages/react-server-dom-relay/src/__tests__/ReactFlightDOMRelay-test.internal.js
index dd5a08fdd467e..a79346676d022 100644
--- a/packages/react-server-dom-relay/src/__tests__/ReactFlightDOMRelay-test.internal.js
+++ b/packages/react-server-dom-relay/src/__tests__/ReactFlightDOMRelay-test.internal.js
@@ -110,7 +110,7 @@ describe('ReactFlightDOMRelay', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(modelClient.greeting);
     });
 
diff --git a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js
index 2fd621c34cead..bdde8502758d7 100644
--- a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js
+++ b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js
@@ -168,7 +168,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe(
@@ -205,7 +205,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe('<p>$1</p>');
@@ -240,7 +240,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe('<p>@div</p>');
@@ -290,7 +290,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe('<p>Hello World</p>');
@@ -328,7 +328,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe('<p>Hello World</p>');
@@ -369,7 +369,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe('<p>Async: Module</p>');
@@ -408,7 +408,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe('<p>Async Text</p>');
@@ -446,7 +446,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe('<p>and then</p>');
@@ -607,7 +607,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<p>(loading)</p>}>
           <ProfilePage response={response} />
@@ -617,17 +617,17 @@ describe('ReactFlightDOM', () => {
     expect(container.innerHTML).toBe('<p>(loading)</p>');
 
     // This isn't enough to show anything.
-    await act(async () => {
+    await act(() => {
       resolveFriends();
     });
     expect(container.innerHTML).toBe('<p>(loading)</p>');
 
     // We can now show the details. Sidebar and posts are still loading.
-    await act(async () => {
+    await act(() => {
       resolveName();
     });
     // Advance time enough to trigger a nested fallback.
-    await act(async () => {
+    await act(() => {
       jest.advanceTimersByTime(500);
     });
     expect(container.innerHTML).toBe(
@@ -723,7 +723,7 @@ describe('ReactFlightDOM', () => {
     const response1 = ReactServerDOMReader.createFromReadableStream(
       stream1.readable,
     );
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<p>(loading)</p>}>
           <Page response={response1} />
@@ -751,7 +751,7 @@ describe('ReactFlightDOM', () => {
     const response2 = ReactServerDOMReader.createFromReadableStream(
       stream2.readable,
     );
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<p>(loading)</p>}>
           <Page response={response2} />
@@ -799,7 +799,7 @@ describe('ReactFlightDOM', () => {
       return use(res);
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <ErrorBoundary
           fallback={e => (
@@ -816,7 +816,7 @@ describe('ReactFlightDOM', () => {
     });
     expect(container.innerHTML).toBe('<p>(loading)</p>');
 
-    await act(async () => {
+    await act(() => {
       abort('for reasons');
     });
     if (__DEV__) {
@@ -862,7 +862,7 @@ describe('ReactFlightDOM', () => {
       return use(res);
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <ErrorBoundary fallback={e => <p>{e.message}</p>}>
           <Suspense fallback={<p>(loading)</p>}>
@@ -913,7 +913,7 @@ describe('ReactFlightDOM', () => {
       return use(res);
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <ErrorBoundary fallback={e => <p>{e.message}</p>}>
           <Suspense fallback={<p>(loading)</p>}>
@@ -925,7 +925,7 @@ describe('ReactFlightDOM', () => {
 
     expect(container.innerHTML).toBe('<p>(loading)</p>');
 
-    await act(async () => {
+    await act(() => {
       rejectPromise(new Error('async module init error'));
     });
 
@@ -975,7 +975,7 @@ describe('ReactFlightDOM', () => {
       return use(res);
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <ErrorBoundary
           fallback={e => (
@@ -1041,7 +1041,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe('<p>async hello</p>');
@@ -1104,7 +1104,7 @@ describe('ReactFlightDOM', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App response={response} />);
     });
     expect(container.innerHTML).toBe(
diff --git a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
index d5aadf7418caa..bc012126aeb9b 100644
--- a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
+++ b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOMBrowser-test.js
@@ -264,7 +264,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback={<p>(loading)</p>}>
           <ProfilePage response={response} />
@@ -274,13 +274,13 @@ describe('ReactFlightDOMBrowser', () => {
     expect(container.innerHTML).toBe('<p>(loading)</p>');
 
     // This isn't enough to show anything.
-    await act(async () => {
+    await act(() => {
       resolveFriends();
     });
     expect(container.innerHTML).toBe('<p>(loading)</p>');
 
     // We can now show the details. Sidebar and posts are still loading.
-    await act(async () => {
+    await act(() => {
       resolveName();
     });
     // Advance time enough to trigger a nested fallback.
@@ -296,7 +296,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const theError = new Error('Game over');
     // Let's *fail* loading games.
-    await act(async () => {
+    await act(() => {
       rejectGames(theError);
     });
 
@@ -315,7 +315,7 @@ describe('ReactFlightDOMBrowser', () => {
     reportedErrors = [];
 
     // We can now show the sidebar.
-    await act(async () => {
+    await act(() => {
       resolvePhotos();
     });
     expect(container.innerHTML).toBe(
@@ -326,7 +326,7 @@ describe('ReactFlightDOMBrowser', () => {
     );
 
     // Show everything.
-    await act(async () => {
+    await act(() => {
       resolvePosts();
     });
     expect(container.innerHTML).toBe(
@@ -414,7 +414,7 @@ describe('ReactFlightDOMBrowser', () => {
     // Advance time enough to trigger a nested fallback.
     jest.advanceTimersByTime(500);
 
-    await act(async () => {});
+    await act(() => {});
 
     expect(flightResponse).toContain('(loading everything)');
     expect(flightResponse).toContain('(loading sidebar)');
@@ -422,25 +422,25 @@ describe('ReactFlightDOMBrowser', () => {
     expect(flightResponse).not.toContain(':friends:');
     expect(flightResponse).not.toContain(':name:');
 
-    await act(async () => {
+    await act(() => {
       resolveFriends();
     });
 
     expect(flightResponse).toContain(':friends:');
 
-    await act(async () => {
+    await act(() => {
       resolveName();
     });
 
     expect(flightResponse).toContain(':name:');
 
-    await act(async () => {
+    await act(() => {
       resolvePhotos();
     });
 
     expect(flightResponse).toContain(':photos:');
 
-    await act(async () => {
+    await act(() => {
       resolvePosts();
     });
 
@@ -512,7 +512,7 @@ describe('ReactFlightDOMBrowser', () => {
       return use(res);
     }
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <ErrorBoundary fallback={errorBoundaryFn}>
           <Suspense fallback={<p>(loading)</p>}>
@@ -523,7 +523,7 @@ describe('ReactFlightDOMBrowser', () => {
     });
     expect(container.innerHTML).toBe('<p>(loading)</p>');
 
-    await act(async () => {
+    await act(() => {
       controller.abort('for reasons');
     });
     const expectedValue = __DEV__
@@ -553,7 +553,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Client />
@@ -587,7 +587,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       // Client uses a different renderer.
       // We reset _currentRenderer here to not trigger a warning about multiple
       // renderers concurrently using this context
@@ -618,7 +618,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(
         <Suspense fallback="Loading...">
           <Client />
@@ -676,7 +676,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(
         <ErrorBoundary>
           <Client />
@@ -712,7 +712,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Client />);
     });
     expect(container.innerHTML).toBe('Hi');
@@ -748,7 +748,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<Client />);
     });
     expect(container.innerHTML).toBe('Hi');
@@ -798,7 +798,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     expect(container.innerHTML).toBe('Click Me');
@@ -840,7 +840,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     expect(container.innerHTML).toBe('Click Me');
@@ -890,7 +890,7 @@ describe('ReactFlightDOMBrowser', () => {
 
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
 
diff --git a/packages/react/src/__tests__/ReactProfiler-test.internal.js b/packages/react/src/__tests__/ReactProfiler-test.internal.js
index f0ae798c1236b..3602a0190be65 100644
--- a/packages/react/src/__tests__/ReactProfiler-test.internal.js
+++ b/packages/react/src/__tests__/ReactProfiler-test.internal.js
@@ -346,7 +346,7 @@ describe(`onRender`, () => {
     Scheduler.unstable_advanceTime(20); // 30 -> 50
 
     // Updating a sibling should not report a re-render.
-    await act(async () => updateProfilerSibling());
+    await act(() => updateProfilerSibling());
 
     expect(callback).not.toHaveBeenCalled();
   });
@@ -672,7 +672,7 @@ describe(`onRender`, () => {
 
     const onRender = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler id="root" onRender={onRender}>
           <Component />
@@ -1590,7 +1590,7 @@ describe(`onCommit`, () => {
     const setCountRef = React.createRef(null);
 
     let renderer = null;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <React.Profiler id="root-mount" onCommit={callback}>
           <React.Profiler id="a">
@@ -1617,7 +1617,7 @@ describe(`onCommit`, () => {
     expect(call[2]).toBe(1010); // durations
     expect(call[3]).toBe(2); // commit start time (before mutations or effects)
 
-    await act(async () => setCountRef.current(count => count + 1));
+    await act(() => setCountRef.current(count => count + 1));
 
     expect(callback).toHaveBeenCalledTimes(2);
 
@@ -1629,7 +1629,7 @@ describe(`onCommit`, () => {
     expect(call[2]).toBe(110); // durations
     expect(call[3]).toBe(1013); // commit start time (before mutations or effects)
 
-    await act(async () => {
+    await act(() => {
       renderer.update(
         <React.Profiler id="root-update" onCommit={callback}>
           <React.Profiler id="b">
@@ -1688,7 +1688,7 @@ describe(`onCommit`, () => {
 
     // Test an error that happens during an effect
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(
         <React.Profiler id="root" onCommit={callback}>
           <ErrorBoundary
@@ -1774,7 +1774,7 @@ describe(`onCommit`, () => {
 
     let renderer = null;
 
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <React.Profiler id="root" onCommit={callback}>
           <ErrorBoundary
@@ -1816,7 +1816,7 @@ describe(`onCommit`, () => {
 
     // Test an error that happens during an cleanup function
 
-    await act(async () => {
+    await act(() => {
       renderer.update(
         <React.Profiler id="root" onCommit={callback}>
           <ErrorBoundary
@@ -1901,7 +1901,7 @@ describe(`onPostCommit`, () => {
     Scheduler.unstable_advanceTime(1);
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <React.Profiler id="mount-test" onPostCommit={callback}>
           <ComponentWithEffects />
@@ -1922,7 +1922,7 @@ describe(`onPostCommit`, () => {
 
     Scheduler.unstable_advanceTime(1);
 
-    await act(async () => {
+    await act(() => {
       renderer.update(
         <React.Profiler id="update-test" onPostCommit={callback}>
           <ComponentWithEffects />
@@ -1943,7 +1943,7 @@ describe(`onPostCommit`, () => {
 
     Scheduler.unstable_advanceTime(1);
 
-    await act(async () => {
+    await act(() => {
       renderer.update(
         <React.Profiler id="unmount-test" onPostCommit={callback} />,
       );
@@ -1985,7 +1985,7 @@ describe(`onPostCommit`, () => {
 
     Scheduler.unstable_advanceTime(1);
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(
         <React.Profiler id="mount-test" onPostCommit={callback}>
           <ComponentWithEffects />
@@ -2033,7 +2033,7 @@ describe(`onPostCommit`, () => {
     const setCountRef = React.createRef(null);
 
     let renderer = null;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <React.Profiler id="root-mount" onPostCommit={callback}>
           <React.Profiler id="a">
@@ -2060,7 +2060,7 @@ describe(`onPostCommit`, () => {
     expect(call[2]).toBe(1010); // durations
     expect(call[3]).toBe(2); // commit start time (before mutations or effects)
 
-    await act(async () => setCountRef.current(count => count + 1));
+    await act(() => setCountRef.current(count => count + 1));
 
     expect(callback).toHaveBeenCalledTimes(2);
 
@@ -2072,7 +2072,7 @@ describe(`onPostCommit`, () => {
     expect(call[2]).toBe(110); // durations
     expect(call[3]).toBe(1013); // commit start time (before mutations or effects)
 
-    await act(async () => {
+    await act(() => {
       renderer.update(
         <React.Profiler id="root-update" onPostCommit={callback}>
           <React.Profiler id="b">
@@ -2131,7 +2131,7 @@ describe(`onPostCommit`, () => {
 
     // Test an error that happens during an effect
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(
         <React.Profiler id="root" onPostCommit={callback}>
           <ErrorBoundary
@@ -2218,7 +2218,7 @@ describe(`onPostCommit`, () => {
 
     let renderer = null;
 
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <React.Profiler id="root" onPostCommit={callback}>
           <ErrorBoundary
@@ -2260,7 +2260,7 @@ describe(`onPostCommit`, () => {
 
     // Test an error that happens during an cleanup function
 
-    await act(async () => {
+    await act(() => {
       renderer.update(
         <React.Profiler id="root" onPostCommit={callback}>
           <ErrorBoundary
@@ -2377,7 +2377,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2438,7 +2438,7 @@ describe(`onNestedUpdateScheduled`, () => {
     const onNestedUpdateScheduledTwo = jest.fn();
     const onNestedUpdateScheduledThree = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="one"
@@ -2486,7 +2486,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.renderToRootWithID(
         <React.Profiler
           id="test"
@@ -2526,7 +2526,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2552,7 +2552,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2563,7 +2563,7 @@ describe(`onNestedUpdateScheduled`, () => {
     });
     assertLog(['Component:false']);
 
-    await act(async () => {
+    await act(() => {
       updateFnRef.current();
     });
     assertLog(['Component:true']);
@@ -2582,7 +2582,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2613,7 +2613,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2627,7 +2627,7 @@ describe(`onNestedUpdateScheduled`, () => {
     expect(onNestedUpdateScheduled).toHaveBeenCalledTimes(1);
     expect(onNestedUpdateScheduled.mock.calls[0][0]).toBe('test');
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2659,7 +2659,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2699,7 +2699,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2711,7 +2711,7 @@ describe(`onNestedUpdateScheduled`, () => {
     assertLog(['Component:false:false']);
     expect(onNestedUpdateScheduled).not.toHaveBeenCalled();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2743,7 +2743,7 @@ describe(`onNestedUpdateScheduled`, () => {
 
     const onNestedUpdateScheduled = jest.fn();
 
-    await act(async () => {
+    await act(() => {
       ReactNoop.render(
         <React.Profiler
           id="test"
@@ -2754,7 +2754,7 @@ describe(`onNestedUpdateScheduled`, () => {
     });
     assertLog(['Component:false']);
 
-    await act(async () => {
+    await act(() => {
       updateFnRef.current();
     });
     assertLog(['Component:true']);
diff --git a/packages/react/src/__tests__/ReactStartTransition-test.js b/packages/react/src/__tests__/ReactStartTransition-test.js
index adf668fc70e14..9e689ac6e7105 100644
--- a/packages/react/src/__tests__/ReactStartTransition-test.js
+++ b/packages/react/src/__tests__/ReactStartTransition-test.js
@@ -47,14 +47,14 @@ describe('ReactStartTransition', () => {
       return null;
     };
 
-    await act(async () => {
+    await act(() => {
       ReactTestRenderer.create(<Component level={0} />, {
         unstable_isConcurrent: true,
       });
     });
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         React.startTransition(() => {
           subs.forEach(setState => {
             setState(state => state + 1);
@@ -71,7 +71,7 @@ describe('ReactStartTransition', () => {
     );
 
     await expect(async () => {
-      await act(async () => {
+      await act(() => {
         triggerHookTransition(() => {
           subs.forEach(setState => {
             setState(state => state + 1);
diff --git a/packages/react/src/__tests__/ReactStrictMode-test.internal.js b/packages/react/src/__tests__/ReactStrictMode-test.internal.js
index 3383fe46ba359..48efe5e7d5fd6 100644
--- a/packages/react/src/__tests__/ReactStrictMode-test.internal.js
+++ b/packages/react/src/__tests__/ReactStrictMode-test.internal.js
@@ -46,7 +46,7 @@ describe('ReactStrictMode', () => {
     }
 
     it('should default to not strict', async () => {
-      await act(async () => {
+      await act(() => {
         const container = document.createElement('div');
         const root = ReactDOMClient.createRoot(container);
         root.render(<Component label="A" />);
@@ -61,7 +61,7 @@ describe('ReactStrictMode', () => {
 
     if (__DEV__) {
       it('should support enabling strict mode via createRoot option', async () => {
-        await act(async () => {
+        await act(() => {
           const container = document.createElement('div');
           const root = ReactDOMClient.createRoot(container, {
             unstable_strictMode: true,
@@ -82,7 +82,7 @@ describe('ReactStrictMode', () => {
       });
 
       it('should include legacy + strict effects mode', async () => {
-        await act(async () => {
+        await act(() => {
           const container = document.createElement('div');
           const root = ReactDOMClient.createRoot(container);
           root.render(
@@ -105,7 +105,7 @@ describe('ReactStrictMode', () => {
       });
 
       it('should allow level to be increased with nesting', async () => {
-        await act(async () => {
+        await act(() => {
           const container = document.createElement('div');
           const root = ReactDOMClient.createRoot(container);
           root.render(
diff --git a/packages/react/src/__tests__/ReactStrictMode-test.js b/packages/react/src/__tests__/ReactStrictMode-test.js
index 59dad3f5cf60f..e99fe83eacf75 100644
--- a/packages/react/src/__tests__/ReactStrictMode-test.js
+++ b/packages/react/src/__tests__/ReactStrictMode-test.js
@@ -356,7 +356,7 @@ describe('ReactStrictMode', () => {
     const root = ReactDOMClient.createRoot(container);
 
     // Mount
-    await act(async () => {
+    await act(() => {
       root.render(
         <React.StrictMode>
           <Uppercased text="hello" />
@@ -372,7 +372,7 @@ describe('ReactStrictMode', () => {
     log = [];
 
     // Update
-    await act(async () => {
+    await act(() => {
       root.render(
         <React.StrictMode>
           <Uppercased text="goodbye" />
@@ -407,7 +407,7 @@ describe('ReactStrictMode', () => {
     const root = ReactDOMClient.createRoot(container);
 
     // Mount
-    await act(async () => {
+    await act(() => {
       root.render(
         <React.StrictMode>
           <Uppercased text="hello" />
@@ -429,7 +429,7 @@ describe('ReactStrictMode', () => {
     log = [];
 
     // Update
-    await act(async () => {
+    await act(() => {
       root.render(
         <React.StrictMode>
           <Uppercased text="goodbye" />
@@ -463,7 +463,7 @@ describe('ReactStrictMode', () => {
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <React.StrictMode>
           <App />
@@ -472,7 +472,7 @@ describe('ReactStrictMode', () => {
     });
     expect(container.textContent).toBe('0');
 
-    await act(async () => {
+    await act(() => {
       setCount(() => {
         log.push('Compute count: 1');
         return 1;
@@ -501,7 +501,7 @@ describe('ReactStrictMode', () => {
     const container = document.createElement('div');
     const root = ReactDOMClient.createRoot(container);
 
-    await act(async () => {
+    await act(() => {
       root.render(
         <React.StrictMode>
           <App />
@@ -510,7 +510,7 @@ describe('ReactStrictMode', () => {
     });
     expect(container.textContent).toBe('0');
 
-    await act(async () => {
+    await act(() => {
       dispatch(1);
     });
     expect(container.textContent).toBe('1');
diff --git a/packages/use-subscription/src/__tests__/useSubscription-test.js b/packages/use-subscription/src/__tests__/useSubscription-test.js
index 46bf1910bbd4a..19eba0a15be8e 100644
--- a/packages/use-subscription/src/__tests__/useSubscription-test.js
+++ b/packages/use-subscription/src/__tests__/useSubscription-test.js
@@ -81,7 +81,7 @@ describe('useSubscription', () => {
 
     const observable = createBehaviorSubject();
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <Subscription source={observable} />,
         {unstable_isConcurrent: true},
@@ -90,14 +90,14 @@ describe('useSubscription', () => {
     assertLog(['default']);
 
     // Updates while subscribed should re-render the child component
-    await act(async () => observable.next(123));
+    await act(() => observable.next(123));
     assertLog([123]);
-    await act(async () => observable.next('abc'));
+    await act(() => observable.next('abc'));
     assertLog(['abc']);
 
     // Unmounting the subscriber should remove listeners
-    await act(async () => renderer.update(<div />));
-    await act(async () => observable.next(456));
+    await act(() => renderer.update(<div />));
+    await act(() => observable.next(456));
     await waitForAll([]);
   });
 
@@ -133,23 +133,21 @@ describe('useSubscription', () => {
 
     let observable = createReplaySubject('initial');
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <Subscription source={observable} />,
         {unstable_isConcurrent: true},
       );
     });
     assertLog(['initial']);
-    await act(async () => observable.next('updated'));
+    await act(() => observable.next('updated'));
     assertLog(['updated']);
 
     await waitForAll([]);
 
     // Unsetting the subscriber prop should reset subscribed values
     observable = createReplaySubject(undefined);
-    await act(async () =>
-      renderer.update(<Subscription source={observable} />),
-    );
+    await act(() => renderer.update(<Subscription source={observable} />));
     assertLog(['default']);
   });
 
@@ -184,7 +182,7 @@ describe('useSubscription', () => {
     expect(subscriptions).toHaveLength(0);
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <Subscription source={observableA} />,
         {unstable_isConcurrent: true},
@@ -197,20 +195,18 @@ describe('useSubscription', () => {
     expect(subscriptions[0]).toBe(observableA);
 
     // Unsetting the subscriber prop should reset subscribed values
-    await act(async () =>
-      renderer.update(<Subscription source={observableB} />),
-    );
+    await act(() => renderer.update(<Subscription source={observableB} />));
 
     assertLog(['b-0']);
     expect(subscriptions).toHaveLength(2);
     expect(subscriptions[1]).toBe(observableB);
 
     // Updates to the old subscribable should not re-render the child component
-    await act(async () => observableA.next('a-1'));
+    await act(() => observableA.next('a-1'));
     await waitForAll([]);
 
     // Updates to the bew subscribable should re-render the child component
-    await act(async () => observableB.next('b-1'));
+    await act(() => observableB.next('b-1'));
     assertLog(['b-1']);
 
     expect(subscriptions).toHaveLength(2);
@@ -245,7 +241,7 @@ describe('useSubscription', () => {
     expect(subscriptions).toHaveLength(0);
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <Subscription source={observableA} />,
         {unstable_isConcurrent: true},
@@ -258,19 +254,17 @@ describe('useSubscription', () => {
     expect(subscriptions[0]).toBe(observableA);
 
     // Unsetting the subscriber prop should reset subscribed values
-    await act(async () =>
-      renderer.update(<Subscription source={observableB} />),
-    );
+    await act(() => renderer.update(<Subscription source={observableB} />));
     assertLog(['b-0']);
     expect(subscriptions).toHaveLength(2);
     expect(subscriptions[1]).toBe(observableB);
 
     // Updates to the old subscribable should not re-render the child component
-    await act(async () => observableA.next('a-1'));
+    await act(() => observableA.next('a-1'));
     await waitForAll([]);
 
     // Updates to the bew subscribable should re-render the child component
-    await act(async () => observableB.next('b-1'));
+    await act(() => observableB.next('b-1'));
     assertLog(['b-1']);
 
     expect(subscriptions).toHaveLength(2);
@@ -335,7 +329,7 @@ describe('useSubscription', () => {
     const observableB = createBehaviorSubject('b-0');
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<Parent observed={observableA} />, {
         unstable_isConcurrent: true,
       });
@@ -359,7 +353,7 @@ describe('useSubscription', () => {
     });
 
     // Update again
-    await act(async () => renderer.update(<Parent observed={observableA} />));
+    await act(() => renderer.update(<Parent observed={observableA} />));
 
     // Flush everything and ensure that the correct subscribable is used
     // We expect the last emitted update to be rendered (because of the commit phase value check)
@@ -438,7 +432,7 @@ describe('useSubscription', () => {
     const observableB = createBehaviorSubject('b-0');
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(<Parent observed={observableA} />, {
         unstable_isConcurrent: true,
       });
@@ -480,7 +474,7 @@ describe('useSubscription', () => {
 
     // Updates from the new subscribable should be ignored.
     log.splice(0);
-    await act(async () => observableB.next('b-1'));
+    await act(() => observableB.next('b-1'));
     await waitForAll([]);
     expect(log).toEqual([]);
   });
@@ -535,7 +529,7 @@ describe('useSubscription', () => {
     });
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <Subscription source={eventHandler} />,
         {unstable_isConcurrent: true},
@@ -569,7 +563,7 @@ describe('useSubscription', () => {
     }
 
     let renderer;
-    await act(async () => {
+    await act(() => {
       renderer = ReactTestRenderer.create(
         <Subscription subscription={subscription1} />,
         {unstable_isConcurrent: true},
@@ -577,7 +571,7 @@ describe('useSubscription', () => {
     });
     await waitForAll([]);
 
-    await act(async () =>
+    await act(() =>
       renderer.update(<Subscription subscription={subscription2} />),
     );
     await waitForAll([]);
diff --git a/packages/use-sync-external-store/src/__tests__/useSyncExternalStoreNative-test.js b/packages/use-sync-external-store/src/__tests__/useSyncExternalStoreNative-test.js
index 560cb390a1adb..fef2d1e76f581 100644
--- a/packages/use-sync-external-store/src/__tests__/useSyncExternalStoreNative-test.js
+++ b/packages/use-sync-external-store/src/__tests__/useSyncExternalStoreNative-test.js
@@ -117,7 +117,7 @@ describe('useSyncExternalStore (userspace shim, server rendering)', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => {
+    await act(() => {
       root.render(<App />);
     });
     assertLog(['client']);
@@ -161,13 +161,13 @@ describe('useSyncExternalStore (userspace shim, server rendering)', () => {
     }
 
     const root = ReactNoop.createRoot();
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
 
     assertLog(['A0', 'B0']);
     expect(root).toMatchRenderedOutput('A0B0');
 
     // Update b but not a
-    await act(async () => {
+    await act(() => {
       store.set({a: 0, b: 1});
     });
     // Only b re-renders
@@ -175,7 +175,7 @@ describe('useSyncExternalStore (userspace shim, server rendering)', () => {
     expect(root).toMatchRenderedOutput('A0B1');
 
     // Update a but not b
-    await act(async () => {
+    await act(() => {
       store.set({a: 1, b: 1});
     });
     // Only a re-renders
diff --git a/packages/use-sync-external-store/src/__tests__/useSyncExternalStoreShared-test.js b/packages/use-sync-external-store/src/__tests__/useSyncExternalStoreShared-test.js
index 67a0c4b0a8f06..1488a8aa3de6c 100644
--- a/packages/use-sync-external-store/src/__tests__/useSyncExternalStoreShared-test.js
+++ b/packages/use-sync-external-store/src/__tests__/useSyncExternalStoreShared-test.js
@@ -142,12 +142,12 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
 
     assertLog(['Initial']);
     expect(container.textContent).toEqual('Initial');
 
-    await act(async () => {
+    await act(() => {
       store.set('Updated');
     });
     assertLog(['Updated']);
@@ -164,13 +164,13 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
 
     assertLog(['Initial']);
     expect(container.textContent).toEqual('Initial');
 
     // Update to the same value
-    await act(async () => {
+    await act(() => {
       store.set('Initial');
     });
     // Should not re-render
@@ -192,19 +192,19 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
 
     assertLog([0]);
     expect(container.textContent).toEqual('0');
 
-    await act(async () => {
+    await act(() => {
       storeA.set(1);
     });
     assertLog([1]);
     expect(container.textContent).toEqual('1');
 
     // Switch stores and update in the same batch
-    await act(async () => {
+    await act(() => {
       ReactDOM.flushSync(() => {
         // This update will be disregarded
         storeA.set(2);
@@ -216,7 +216,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
     expect(container.textContent).toEqual('0');
 
     // Update A
-    await act(async () => {
+    await act(() => {
       storeA.set(3);
     });
     // Nothing happened, because we're no longer subscribed to A
@@ -224,7 +224,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
     expect(container.textContent).toEqual('0');
 
     // Update B
-    await act(async () => {
+    await act(() => {
       storeB.set(1);
     });
     assertLog([1]);
@@ -254,13 +254,13 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
 
     assertLog(['A0', 'B0']);
     expect(container.textContent).toEqual('A0B0');
 
     // Update b but not a
-    await act(async () => {
+    await act(() => {
       store.set({a: 0, b: 1});
     });
     // Only b re-renders
@@ -268,7 +268,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
     expect(container.textContent).toEqual('A0B1');
 
     // Update a but not b
-    await act(async () => {
+    await act(() => {
       store.set({a: 1, b: 1});
     });
     // Only a re-renders
@@ -295,7 +295,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
       const container = document.createElement('div');
       const root = createRoot(container);
-      await act(async () => root.render(<App />));
+      await act(() => root.render(<App />));
       assertLog([0, 'Passive effect: 0']);
 
       // Schedule an update. We'll intentionally not use `act` so that we can
@@ -365,11 +365,11 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
     assertLog(['A1']);
     expect(container.textContent).toEqual('A1');
 
-    await act(async () => {
+    await act(() => {
       // Change getSnapshot and update the store in the same batch
       setStep(1);
     });
@@ -423,13 +423,13 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
     assertLog(['A1']);
     expect(container.textContent).toEqual('A1');
 
     // This will cause a layout effect, and in the layout effect we'll update
     // the store
-    await act(async () => {
+    await act(() => {
       setStep(1);
     });
     assertLog([
@@ -463,7 +463,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () =>
+    await act(() =>
       root.render(
         <>
           <Child1 />
@@ -474,7 +474,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
     assertLog([0, 0]);
     expect(container.textContent).toEqual('00');
 
-    await act(async () => {
+    await act(() => {
       store.set(1);
     });
     assertLog([1, 1, 'Reset back to 0', 0, 0]);
@@ -497,11 +497,11 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
     assertLog([0]);
 
     // Update the store and getSnapshot at the same time
-    await act(async () => {
+    await act(() => {
       ReactDOM.flushSync(() => {
         setGetSnapshot(() => getSnapshotB);
         store.set({a: 1, b: 2});
@@ -546,7 +546,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
     const errorBoundary = React.createRef(null);
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () =>
+    await act(() =>
       root.render(
         <ErrorBoundary ref={errorBoundary}>
           <App />
@@ -557,7 +557,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
     expect(container.textContent).toEqual('0');
 
     // Update that throws in a getSnapshot. We can catch it with an error boundary.
-    await act(async () => {
+    await act(() => {
       store.set({value: 1, throwInGetSnapshot: true, throwInIsEqual: false});
     });
     if (gate(flags => !flags.enableUseSyncExternalStoreShim)) {
@@ -612,15 +612,15 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     // Initial render that reads a snapshot of NaN. This is OK because we use
     // Object.is algorithm to compare values.
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
     expect(container.textContent).toEqual('NaN');
 
     // Update to real number
-    await act(async () => store.set(123));
+    await act(() => store.set(123));
     expect(container.textContent).toEqual('123');
 
     // Update back to NaN
-    await act(async () => store.set('not a number'));
+    await act(() => store.set('not a number'));
     expect(container.textContent).toEqual('NaN');
   });
 
@@ -648,13 +648,13 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
       const container = document.createElement('div');
       const root = createRoot(container);
-      await act(async () => root.render(<App />));
+      await act(() => root.render(<App />));
 
       assertLog(['App', 'Selector', 'A0']);
       expect(container.textContent).toEqual('A0');
 
       // Update the store
-      await act(async () => {
+      await act(() => {
         store.set({a: 1, b: 0});
       });
       assertLog([
@@ -707,13 +707,13 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
       const container = document.createElement('div');
       const root = createRoot(container);
-      await act(async () => root.render(<App />));
+      await act(() => root.render(<App />));
 
       assertLog(['A0', 'B0']);
       expect(container.textContent).toEqual('A0B0');
 
       // Update b but not a
-      await act(async () => {
+      await act(() => {
         store.set({a: 0, b: 1});
       });
       // Only b re-renders
@@ -721,7 +721,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
       expect(container.textContent).toEqual('A0B1');
 
       // Update a but not b
-      await act(async () => {
+      await act(() => {
         store.set({a: 1, b: 1});
       });
       // Only a re-renders
@@ -754,7 +754,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
       const serverRenderedDiv = container.getElementsByTagName('div')[0];
 
       if (gate(flags => !flags.enableUseSyncExternalStoreShim)) {
-        await act(async () => {
+        await act(() => {
           ReactDOMClient.hydrateRoot(container, <App />);
         });
         assertLog([
@@ -770,7 +770,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
         // currently hydrating, so `getServerSnapshot` is not called on the
         // client. To avoid this server mismatch warning, user must account for
         // this themselves and return the correct value inside `getSnapshot`.
-        await act(async () => {
+        await act(() => {
           expect(() => ReactDOM.hydrate(<App />, container)).toErrorDev(
             'Text content did not match',
           );
@@ -797,12 +797,12 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => root.render(<App />));
+    await act(() => root.render(<App />));
 
     assertLog(['INITIAL']);
     expect(container.textContent).toEqual('INITIAL');
 
-    await act(async () => {
+    await act(() => {
       store.set('Updated');
     });
     assertLog(['UPDATED']);
@@ -860,12 +860,12 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
     const container = document.createElement('div');
     const root = createRoot(container);
-    await act(async () => {
+    await act(() => {
       root.render(<App step={0} />);
     });
     assertLog(['Inline selector', 'A', 'B', 'C', 'Sibling: 0']);
 
-    await act(async () => {
+    await act(() => {
       root.render(<App step={1} />);
     });
     assertLog([
@@ -920,7 +920,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
       const container = document.createElement('div');
       const root = createRoot(container);
-      await act(async () =>
+      await act(() =>
         root.render(
           <ErrorBoundary>
             <App />
@@ -931,7 +931,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
       expect(container.textContent).toEqual('A');
 
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           store.set({});
         });
       }).toWarnDev(
@@ -965,7 +965,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
 
       const container = document.createElement('div');
       const root = createRoot(container);
-      await act(async () =>
+      await act(() =>
         root.render(
           <ErrorBoundary>
             <App />
@@ -976,7 +976,7 @@ describe('Shared useSyncExternalStore behavior (shim and built-in)', () => {
       expect(container.textContent).toEqual('A');
 
       await expect(async () => {
-        await act(async () => {
+        await act(() => {
           store.set({});
         });
       }).toWarnDev(