diff --git a/flow-typed/environment/node.js b/flow-typed/environment/node.js
index 959f77da01..cb70c63a4e 100644
--- a/flow-typed/environment/node.js
+++ b/flow-typed/environment/node.js
@@ -2549,7 +2549,7 @@ declare module 'fs' {
       ...
     }>,
     writeFile(
-      FSPromisePath | FileHandle,
+      v0: FSPromisePath | FileHandle,
       data: string | Buffer | Uint8Array,
       options?: string | WriteOptions,
     ): Promise<void>,
@@ -3343,9 +3343,9 @@ declare module 'perf_hooks' {
     setResourceTimingBufferSize(maxSize: number): void;
     readonly timeOrigin: number;
     timerify<TArgs extends Iterable<unknown>, TReturn>(
-      fn: (...TArgs) => TReturn,
+      fn: (...rest: TArgs) => TReturn,
       options?: Readonly<{histogram?: RecordableHistogram}>,
-    ): (...TArgs) => TReturn;
+    ): (...rest: TArgs) => TReturn;
     toJSON(): unknown;
   }
 
@@ -3537,7 +3537,7 @@ type readline$InterfaceCompleter = (
   | [Array<string>, string]
   | ((
       line: string,
-      ((err: ?Error, data: [Array<string>, string]) => void),
+      v1: (err: ?Error, data: [Array<string>, string]) => void,
     ) => void);
 
 declare class readline$Interface extends events$EventEmitter {
@@ -5630,18 +5630,18 @@ declare class Process extends events$EventEmitter {
   emitWarning(warning: string | Error): void;
   emitWarning(
     warning: string,
-    typeOrCtor: string | ((...empty) => unknown),
+    typeOrCtor: string | ((...rest: empty) => unknown),
   ): void;
   emitWarning(
     warning: string,
     type: string,
-    codeOrCtor: string | ((...empty) => unknown),
+    codeOrCtor: string | ((...rest: empty) => unknown),
   ): void;
   emitWarning(
     warning: string,
     type: string,
     code: string,
-    ctor?: (...empty) => unknown,
+    ctor?: (...rest: empty) => unknown,
   ): void;
   execArgv: Array<string>;
   execPath: string;
@@ -5671,7 +5671,7 @@ declare class Process extends events$EventEmitter {
     },
     rss: () => number,
   };
-  nextTick: <T>(cb: (...T) => unknown, ...T) => void;
+  nextTick: <T>(cb: (...rest: T) => unknown, ...rest: T) => void;
   pid: number;
   platform: string;
   release: {
diff --git a/flow-typed/fb-watchman.js b/flow-typed/fb-watchman.js
index fd629bee53..209ada0e26 100644
--- a/flow-typed/fb-watchman.js
+++ b/flow-typed/fb-watchman.js
@@ -235,11 +235,14 @@ declare module 'fb-watchman' {
     ): void;
     end(): void;
 
-    on('connect', () => void): void;
-    on('end', () => void): void;
-    on('error', (error: Error) => void): void;
-    on('subscription', (event: WatchmanSubscriptionEvent) => void): void;
-    on('log', (event: WatchmanLogEvent) => void): void;
+    on(v0: 'connect', v1: () => void): void;
+    on(v0: 'end', v1: () => void): void;
+    on(v0: 'error', v1: (error: Error) => void): void;
+    on(
+      v0: 'subscription',
+      v1: (event: WatchmanSubscriptionEvent) => void,
+    ): void;
+    on(v0: 'log', v1: (event: WatchmanLogEvent) => void): void;
     removeAllListeners: (eventName?: string) => void;
   }
 
diff --git a/flow-typed/jest-worker.js b/flow-typed/jest-worker.js
index ddcc169c96..86f0e4a682 100644
--- a/flow-typed/jest-worker.js
+++ b/flow-typed/jest-worker.js
@@ -263,7 +263,7 @@ declare module 'jest-worker' {
 
   declare export class Worker<
     TExposed extends Readonly<{
-      [string]: (...Array<$FlowFixMe>) => Promise<$FlowFixMe>,
+      [string]: (...rest: Array<$FlowFixMe>) => Promise<$FlowFixMe>,
     }> = {},
     TSetupArgs extends ReadonlyArray<unknown> = ReadonlyArray<unknown>,
   > {
diff --git a/flow-typed/jest.js b/flow-typed/jest.js
index 97317e80cd..41eb31eeaf 100644
--- a/flow-typed/jest.js
+++ b/flow-typed/jest.js
@@ -1191,9 +1191,9 @@ type JestPrettyFormatColors = {
   ...
 };
 
-type JestPrettyFormatIndent = string => string;
+type JestPrettyFormatIndent = (v: string) => string;
 type JestPrettyFormatRefs = Array<any>;
-type JestPrettyFormatPrint = any => string;
+type JestPrettyFormatPrint = (v: any) => string;
 type JestPrettyFormatStringOrNull = string | null;
 
 type JestPrettyFormatOptions = {|
@@ -1224,7 +1224,7 @@ type JestPrettyFormatPlugin = {
     opts: JestPrettyFormatOptions,
     colors: JestPrettyFormatColors,
   ) => string,
-  test: any => boolean,
+  test: (v: any) => boolean,
   ...
 };
 
diff --git a/flow-typed/npm/babel-traverse_v7.x.x.js b/flow-typed/npm/babel-traverse_v7.x.x.js
index 12f4570389..93dbe352d2 100644
--- a/flow-typed/npm/babel-traverse_v7.x.x.js
+++ b/flow-typed/npm/babel-traverse_v7.x.x.js
@@ -631,7 +631,7 @@ declare module '@babel/traverse' {
 
     constructor(hub: HubInterface, parent: BabelNode): NodePath<TNode>;
 
-    static get({
+    static get(v: {
       hub: HubInterface,
       parentPath: ?NodePath<>,
       parent: BabelNode,
diff --git a/flow-typed/npm/babel_v7.x.x.js b/flow-typed/npm/babel_v7.x.x.js
index ea721fb17c..c3a6e73508 100644
--- a/flow-typed/npm/babel_v7.x.x.js
+++ b/flow-typed/npm/babel_v7.x.x.js
@@ -387,7 +387,7 @@ declare module '@babel/core' {
     buildCodeFrameError<TError extends Error>(
       node: BabelNode,
       msg: string,
-      Class<TError>,
+      v2: Class<TError>,
     ): TError;
 
     mergeSourceMap(map: _BabelSourceMap): _BabelSourceMap;
@@ -408,7 +408,7 @@ declare module '@babel/core' {
 
     parseShebang(): void;
 
-    makeResult<T>(TransformResult<T>): TransformResult<T>;
+    makeResult<T>(v: TransformResult<T>): TransformResult<T>;
 
     generate(): TransformResult<>;
   }
@@ -955,8 +955,8 @@ declare module '@babel/core' {
   |};
 
   declare type TransformCallback<TMetadata> =
-    | ((Error, null) => unknown)
-    | ((null, TransformResult<TMetadata> | null) => unknown);
+    | ((v0: Error, v1: null) => unknown)
+    | ((v0: null, v1: TransformResult<TMetadata> | null) => unknown);
 
   /**
    * Transforms the passed in code. Calling a callback with an object with the generated code, source map, and AST.
@@ -1042,7 +1042,8 @@ declare module '@babel/core' {
   declare export function parse(
     code: string,
     options?: BabelCoreOptions,
-    callback: ((error: Error) => void) | ((void, BabelNodeFile) => void),
+    callback:
+      ((error: Error) => void) | ((v0: void, v1: BabelNodeFile) => void),
   ): void;
 
   declare export function parseSync(
@@ -1096,8 +1097,8 @@ declare module '@babel/core' {
   declare export function loadOptions(
     options?: unknown,
     callback:
-      | ((error: Error, null) => unknown)
-      | ((null, config: ResolvedConfig | null) => unknown),
+      | ((error: Error, v1: null) => unknown)
+      | ((v0: null, config: ResolvedConfig | null) => unknown),
   ): void;
   declare export function loadOptionsSync(
     options?: unknown,
@@ -1125,8 +1126,8 @@ declare module '@babel/core' {
   declare export function loadPartialConfig(
     options?: unknown,
     callback:
-      | ((error: Error, null) => unknown)
-      | ((null, config: PartialConfig | null) => unknown),
+      | ((error: Error, v1: null) => unknown)
+      | ((v0: null, config: PartialConfig | null) => unknown),
   ): void;
   declare export function loadPartialConfigSync(
     options?: unknown,
@@ -1314,10 +1315,13 @@ declare module '@babel/template' {
     (opts: PublicOpts): TemplateBuilder<T>,
 
     // Building from a string produces an AST builder function by default.
-    (tpl: string, opts: ?PublicOpts): (?PublicReplacements) => T,
+    (tpl: string, opts: ?PublicOpts): (v: ?PublicReplacements) => T,
 
     // Building from a template literal produces an AST builder function by default.
-    (tpl: Array<string>, ...args: Array<unknown>): (?PublicReplacements) => T,
+    (
+      tpl: Array<string>,
+      ...args: Array<unknown>
+    ): (v: ?PublicReplacements) => T,
 
     // Allow users to explicitly create templates that produce ASTs, skipping
     // the need for an intermediate function.
@@ -1350,13 +1354,13 @@ declare module '@babel/template' {
     (
       tpl: string,
       opts: ?PublicOpts,
-    ): (?PublicReplacements) => Statement | Array<Statement>,
+    ): (v: ?PublicReplacements) => Statement | Array<Statement>,
 
     // Building from a template literal produces an AST builder function by default.
     (
       tpl: Array<string>,
       ...args: Array<unknown>
-    ): (?PublicReplacements) => Statement | Array<Statement>,
+    ): (v: ?PublicReplacements) => Statement | Array<Statement>,
 
     // Allow users to explicitly create templates that produce ASTs, skipping
     // the need for an intermediate function.
diff --git a/flow-typed/npm/ws_v7.x.x.js b/flow-typed/npm/ws_v7.x.x.js
index 9a9639d4e5..4dc479b4fd 100644
--- a/flow-typed/npm/ws_v7.x.x.js
+++ b/flow-typed/npm/ws_v7.x.x.js
@@ -47,20 +47,20 @@ declare class ws$WebSocketServer extends events$EventEmitter {
   /**
    * Emitted when the server closes.
    */
-  on(event: 'close', () => unknown): this;
+  on(event: 'close', v1: () => unknown): this;
 
   /**
    * Emitted when the handshake is complete.
    */
   on(
     event: 'connection',
-    (socket: ws$WebSocket, request: http$IncomingMessage<>) => unknown,
+    v1: (socket: ws$WebSocket, request: http$IncomingMessage<>) => unknown,
   ): this;
 
   /**
    * Emitted when an error occurs on the underlying server.
    */
-  on(event: 'error', (error: Error) => unknown): this;
+  on(event: 'error', v1: (error: Error) => unknown): this;
 
   /**
    * Emitted before the response headers are written to the socket as part of
@@ -68,13 +68,13 @@ declare class ws$WebSocketServer extends events$EventEmitter {
    */
   on(
     event: 'headers',
-    (headers: Array<string>, request: http$IncomingMessage<>) => unknown,
+    v1: (headers: Array<string>, request: http$IncomingMessage<>) => unknown,
   ): this;
 
   /**
    * Emitted when the underlying server has been bound.
    */
-  on(event: 'listening', () => unknown): this;
+  on(event: 'listening', v1: () => unknown): this;
 
   /**
    * Returns the bound address, the address family name, and port of the server
@@ -102,7 +102,7 @@ declare class ws$WebSocketServer extends events$EventEmitter {
     request: http$IncomingMessage<>,
     socket: net$Socket,
     head: Buffer,
-    callback: (?ws$WebSocket) => unknown,
+    callback: (v: ?ws$WebSocket) => unknown,
   ): void;
 
   /**
@@ -137,8 +137,8 @@ declare type ws$MessageListener = (
   isBinary: boolean,
 ) => unknown;
 declare type ws$OpenListener = () => unknown;
-declare type ws$PingListener = (Buffer) => unknown;
-declare type ws$PongListener = (Buffer) => unknown;
+declare type ws$PingListener = (v: Buffer) => unknown;
+declare type ws$PongListener = (v: Buffer) => unknown;
 declare type ws$UnexpectedResponseListener = (
   request: http$ClientRequest<>,
   response: http$IncomingMessage<>,
@@ -173,44 +173,44 @@ declare class ws$WebSocket extends events$EventEmitter {
   /*
    * Emitted when the connection is closed.
    */
-  on('close', ws$CloseListener): this;
+  on(v0: 'close', v1: ws$CloseListener): this;
 
   /*
    * Emitted when an error occurs.
    */
-  on('error', ws$ErrorListener): this;
+  on(v0: 'error', v1: ws$ErrorListener): this;
 
   /*
    * Emitted when a message is received from the server.
    */
-  on('message', ws$MessageListener): this;
+  on(v0: 'message', v1: ws$MessageListener): this;
 
   /*
    * Emitted when the connection is established.
    */
-  on('open', ws$OpenListener): this;
+  on(v0: 'open', v1: ws$OpenListener): this;
 
   /*
    * Emitted when a ping is received from the server.
    */
-  on('ping', ws$PingListener): this;
+  on(v0: 'ping', v1: ws$PingListener): this;
 
   /*
    * Emitted when a pong is received from the server.
    */
-  on('pong', ws$PongListener): this;
+  on(v0: 'pong', v1: ws$PongListener): this;
 
   /*
    * Emitted when the server response is not the expected one,
    * for example a 401 response.
    */
-  on('unexpected-response', ws$UnexpectedResponseListener): this;
+  on(v0: 'unexpected-response', v1: ws$UnexpectedResponseListener): this;
 
   /*
    * Emitted when response headers are received from the server as part of the
    * handshake.
    */
-  on('upgrade', ws$UpgradeListener): this;
+  on(v0: 'upgrade', v1: ws$UpgradeListener): this;
 
   /**
    * Register an event listener emulating the `EventTarget` interface.
@@ -247,7 +247,7 @@ declare class ws$WebSocket extends events$EventEmitter {
   ): this;
   addEventListener(
     type: 'unexpected-response',
-    ws$UnexpectedResponseListener,
+    v1: ws$UnexpectedResponseListener,
     options?: {once?: boolean},
   ): this;
   addEventListener(
@@ -313,7 +313,7 @@ declare class ws$WebSocket extends events$EventEmitter {
   removeEventListener(type: 'pong', listener: ws$PongListener): this;
   removeEventListener(
     type: 'unexpected-response',
-    ws$UnexpectedResponseListener,
+    v1: ws$UnexpectedResponseListener,
   ): this;
   removeEventListener(type: 'upgrade', listener: ws$UpgradeListener): this;
 
diff --git a/packages/buck-worker-tool/src/worker-tool.js b/packages/buck-worker-tool/src/worker-tool.js
index d8f7b507cc..9212c23c1a 100644
--- a/packages/buck-worker-tool/src/worker-tool.js
+++ b/packages/buck-worker-tool/src/worker-tool.js
@@ -67,14 +67,20 @@ type IncomingMessage = HandshakeMessage | CommandMessage;
 type Response = HandshakeResponse | CommandResponse | ErrorResponse;
 type RespondFn = (response: Response) => void;
 
-type JSONReaderDataHandler = IncomingMessage => unknown;
+type JSONReaderDataHandler = (v: IncomingMessage) => unknown;
 type JSONReaderEndHandler = () => unknown;
 
-type JSONReaderDataListener = ('data', JSONReaderDataHandler) => JSONReader;
-type JSONReaderEndListener = ('end', JSONReaderEndHandler) => JSONReader;
+type JSONReaderDataListener = (
+  v0: 'data',
+  v1: JSONReaderDataHandler,
+) => JSONReader;
+type JSONReaderEndListener = (
+  v0: 'end',
+  v1: JSONReaderEndHandler,
+) => JSONReader;
 type JSONReaderRootEndListener = (
-  'root_end',
-  JSONReaderEndHandler,
+  v0: 'root_end',
+  v1: JSONReaderEndHandler,
 ) => JSONReader;
 type JSONReaderListener = JSONReaderDataListener &
   JSONReaderEndListener &
diff --git a/packages/metro-config/src/loadConfig.js b/packages/metro-config/src/loadConfig.js
index 59c4b0e298..03024d0285 100644
--- a/packages/metro-config/src/loadConfig.js
+++ b/packages/metro-config/src/loadConfig.js
@@ -246,7 +246,7 @@ function concatUnique<T>(
 async function mergeConfigAsync<T extends InputConfigT>(
   baseConfig: Promise<T>,
   ...reversedConfigs: ReadonlyArray<
-    InputConfigT | (T => InputConfigT) | (T => Promise<InputConfigT>),
+    InputConfigT | ((v: T) => InputConfigT) | ((v: T) => Promise<InputConfigT>),
   >
 ): Promise<T> {
   let currentConfig: T = await baseConfig;
diff --git a/packages/metro-core/src/Terminal.js b/packages/metro-core/src/Terminal.js
index f5029e879c..e6402ad90c 100644
--- a/packages/metro-core/src/Terminal.js
+++ b/packages/metro-core/src/Terminal.js
@@ -104,7 +104,7 @@ export default class Terminal {
   #isUpdating: boolean;
   #hasPendingUpdate: boolean;
   #isFlushRequested: boolean;
-  #writeNonTTYStatusThrottled: string => void;
+  #writeNonTTYStatusThrottled: (v: string) => void;
   #bytesWrittenAfterStatus: ?number;
 
   constructor(stream: UnderlyingStream, opts: {ttyPrint?: boolean} = {}) {
diff --git a/packages/metro-file-map/src/crawlers/__tests__/integration-test.js b/packages/metro-file-map/src/crawlers/__tests__/integration-test.js
index 16f8591185..fc937e6386 100644
--- a/packages/metro-file-map/src/crawlers/__tests__/integration-test.js
+++ b/packages/metro-file-map/src/crawlers/__tests__/integration-test.js
@@ -54,7 +54,7 @@ declare var expect: {
   extend(matchers: {[name: string]: JestMatcher, ...}): void,
   assertions(expectedAssertions: number): void,
   any(value: unknown): JestAsymmetricEqualityType,
-  oneOf: (unknown, unknown) => boolean,
+  oneOf: (v0: unknown, v1: unknown) => boolean,
   ...
 };
 
diff --git a/packages/metro-file-map/src/crawlers/watchman/__tests__/index-test.js b/packages/metro-file-map/src/crawlers/watchman/__tests__/index-test.js
index 230e7f6863..80e030bd6c 100644
--- a/packages/metro-file-map/src/crawlers/watchman/__tests__/index-test.js
+++ b/packages/metro-file-map/src/crawlers/watchman/__tests__/index-test.js
@@ -28,11 +28,11 @@ jest.mock('fb-watchman', () => ({
 }));
 
 // /some/path on posix, c:\some\path on Windows
-const systemPath: string => string = filePath =>
+const systemPath: (v: string) => string = filePath =>
   watchmanPath(filePath).replace(/\//g, path.sep);
 
 // /some/path on posix, c:/some/path on Windows. Relative unchanged.
-const watchmanPath: string => string = filePath =>
+const watchmanPath: (v: string) => string = filePath =>
   filePath.replace(/^\//, 'C:/');
 
 const DEFAULT_OPTIONS: CrawlerOptions = {
diff --git a/packages/metro-file-map/src/flow-types.js b/packages/metro-file-map/src/flow-types.js
index cfb4f35338..cdd7eebb4c 100644
--- a/packages/metro-file-map/src/flow-types.js
+++ b/packages/metro-file-map/src/flow-types.js
@@ -277,7 +277,7 @@ export type FileMapPluginWorker = Readonly<{
    * This applies to files under node_modules too, which a plugin may reject
    * using `isNodeModules`.
    */
-  filter: ({normalPath: string, isNodeModules: boolean}) => boolean,
+  filter: (v: {normalPath: string, isNodeModules: boolean}) => boolean,
   /**
    * If true, the worker is not run on files as they are crawled or changed,
    * and `filter` is not consulted. It runs only on the files the plugin asks
@@ -316,8 +316,8 @@ export type InputFileMapPlugin = FileMapPlugin<empty, empty>;
 
 export interface MetadataWorker {
   processFile(
-    WorkerMessage,
-    Readonly<{getContent: () => Buffer}>,
+    v0: WorkerMessage,
+    v1: Readonly<{getContent: () => Buffer}>,
   ): V8Serializable;
 }
 
diff --git a/packages/metro-file-map/src/index.js b/packages/metro-file-map/src/index.js
index a2c8ec0d49..8812ca6c30 100644
--- a/packages/metro-file-map/src/index.js
+++ b/packages/metro-file-map/src/index.js
@@ -1324,10 +1324,10 @@ const toPublicMetadata = (
 });
 
 // TODO: Replace with it.map() from Node 22+
-const mapIterable: <T, S>(Iterable<T>, (T) => S) => IteratorObject<S> = (
-  it,
-  fn,
-) =>
+const mapIterable: <T, S>(
+  v0: Iterable<T>,
+  v1: (v: T) => S,
+) => IteratorObject<S> = (it, fn) =>
   (function* mapped() {
     for (const item of it) {
       yield fn(item);
diff --git a/packages/metro-file-map/src/lib/FileProcessor.js b/packages/metro-file-map/src/lib/FileProcessor.js
index f4c118af6b..e5133d4319 100644
--- a/packages/metro-file-map/src/lib/FileProcessor.js
+++ b/packages/metro-file-map/src/lib/FileProcessor.js
@@ -41,7 +41,7 @@ type ProcessFileRequest = Readonly<{
 }>;
 
 interface AsyncWorker {
-  readonly processFile: WorkerMessage => Promise<WorkerMetadata>;
+  readonly processFile: (v: WorkerMessage) => Promise<WorkerMetadata>;
   readonly end: () => Promise<void>;
 }
 
@@ -237,7 +237,7 @@ export class FileProcessor {
     debug('Creating worker farm of %d worker threads', numWorkers);
     this.#perfLogger?.point('initWorkers_start');
     const jestWorker = new JestWorker<{
-      processFile: WorkerMessage => Promise<WorkerMetadata>,
+      processFile: (v: WorkerMessage) => Promise<WorkerMetadata>,
     }>(workerPath, {
       exposedMethods: ['processFile'],
       maxRetries: 3,
diff --git a/packages/metro-file-map/src/lib/__tests__/FileProcessor-test.js b/packages/metro-file-map/src/lib/__tests__/FileProcessor-test.js
index b6506cd743..c0e21100fe 100644
--- a/packages/metro-file-map/src/lib/__tests__/FileProcessor-test.js
+++ b/packages/metro-file-map/src/lib/__tests__/FileProcessor-test.js
@@ -29,7 +29,7 @@ const mockWorkerFn = jest.fn().mockReturnValue({});
 
 // Convenience function to write paths with posix separators but convert them
 // to system separators
-const p: string => string = filePath =>
+const p: (v: string) => string = filePath =>
   process.platform === 'win32'
     ? filePath.replace(/\//g, '\\').replace(/^\\/, 'C:\\')
     : filePath;
@@ -54,7 +54,7 @@ describe('processBatch', () => {
       setup: () => {},
       processFile: mockWorkerFn,
       Worker: class {
-        processFile: WorkerMessage => WorkerMetadata = mockWorkerFn;
+        processFile: (v: WorkerMessage) => WorkerMetadata = mockWorkerFn;
       },
     }));
     FileProcessor = require('../FileProcessor').FileProcessor;
diff --git a/packages/metro-file-map/src/lib/__tests__/RootPathUtils-test.js b/packages/metro-file-map/src/lib/__tests__/RootPathUtils-test.js
index b4e4499197..e20667f4f3 100644
--- a/packages/metro-file-map/src/lib/__tests__/RootPathUtils-test.js
+++ b/packages/metro-file-map/src/lib/__tests__/RootPathUtils-test.js
@@ -17,7 +17,7 @@ jest.mock('node:path', () => mockPathModule);
 describe.each([['win32'], ['posix']])('RootPathUtils on %s', platform => {
   // Convenience function to write paths with posix separators but convert them
   // to system separators
-  const p: string => string = filePath =>
+  const p: (v: string) => string = filePath =>
     platform === 'win32'
       ? filePath.replace(/\//g, '\\').replace(/^\\/, 'C:\\')
       : filePath;
diff --git a/packages/metro-file-map/src/lib/__tests__/TreeFS-test.js b/packages/metro-file-map/src/lib/__tests__/TreeFS-test.js
index b4da33f879..356aab4f10 100644
--- a/packages/metro-file-map/src/lib/__tests__/TreeFS-test.js
+++ b/packages/metro-file-map/src/lib/__tests__/TreeFS-test.js
@@ -31,7 +31,7 @@ jest.mock('node:path', () => mockPathModule);
 describe.each([['win32'], ['posix']])('TreeFS on %s', platform => {
   // Convenience function to write paths with posix separators but convert them
   // to system separators
-  const p: string => string = filePath =>
+  const p: (v: string) => string = filePath =>
     platform === 'win32'
       ? filePath.replace(/\//g, '\\').replace(/^\\/, 'C:\\')
       : filePath;
diff --git a/packages/metro-file-map/src/plugins/HastePlugin.js b/packages/metro-file-map/src/plugins/HastePlugin.js
index c542493c38..24d76f0c65 100644
--- a/packages/metro-file-map/src/plugins/HastePlugin.js
+++ b/packages/metro-file-map/src/plugins/HastePlugin.js
@@ -61,7 +61,7 @@ export default class HastePlugin
   readonly #duplicates: DuplicatesIndex = new Map();
   readonly #enableHastePackages: boolean;
   readonly #failValidationOnConflicts: boolean;
-  #getModuleNameByPath: string => ?string;
+  #getModuleNameByPath: (v: string) => ?string;
   readonly #hasteImplModulePath: ?string;
   readonly #map: Map<string, HasteMapItem> = new Map();
   readonly #pathUtils: RootPathUtils;
diff --git a/packages/metro-file-map/src/plugins/haste/__tests__/HastePlugin-test.js b/packages/metro-file-map/src/plugins/haste/__tests__/HastePlugin-test.js
index 12a6bb8038..90edd2e3a9 100644
--- a/packages/metro-file-map/src/plugins/haste/__tests__/HastePlugin-test.js
+++ b/packages/metro-file-map/src/plugins/haste/__tests__/HastePlugin-test.js
@@ -19,7 +19,7 @@ let mockPathModule;
 jest.mock('node:path', () => mockPathModule);
 
 describe.each([['win32'], ['posix']])('HastePlugin on %s', platform => {
-  const p: string => string = filePath =>
+  const p: (v: string) => string = filePath =>
     platform === 'win32'
       ? filePath.replace(/\//g, '\\').replace(/^\\/, 'C:\\')
       : filePath;
diff --git a/packages/metro-file-map/src/plugins/mocks/__tests__/MockPlugin-test.js b/packages/metro-file-map/src/plugins/mocks/__tests__/MockPlugin-test.js
index 94316bb49d..6bbc3f0787 100644
--- a/packages/metro-file-map/src/plugins/mocks/__tests__/MockPlugin-test.js
+++ b/packages/metro-file-map/src/plugins/mocks/__tests__/MockPlugin-test.js
@@ -15,7 +15,7 @@ let mockPathModule;
 jest.mock('node:path', () => mockPathModule);
 
 describe.each([['win32'], ['posix']])('MockPlugin on %s', platform => {
-  const p: string => string = filePath =>
+  const p: (v: string) => string = filePath =>
     platform === 'win32'
       ? filePath.replace(/\//g, '\\').replace(/^\\/, 'C:\\')
       : filePath;
diff --git a/packages/metro-file-map/src/watchers/FallbackWatcher.js b/packages/metro-file-map/src/watchers/FallbackWatcher.js
index dba8ac4b47..47fc5d8c18 100644
--- a/packages/metro-file-map/src/watchers/FallbackWatcher.js
+++ b/packages/metro-file-map/src/watchers/FallbackWatcher.js
@@ -499,10 +499,10 @@ function isIgnorableFileError(error: Error | {code: string}) {
  */
 async function recReaddir(
   root: string,
-  dirCallback: (string, Stats) => void,
-  fileCallback: (string, Stats) => void,
-  symlinkCallback: (string, Stats) => void,
-  errorCallback: Error => void,
+  dirCallback: (v0: string, v1: Stats) => void,
+  fileCallback: (v0: string, v1: Stats) => void,
+  symlinkCallback: (v0: string, v1: Stats) => void,
+  errorCallback: (v: Error) => void,
   ignored: ?RegExp,
 ): Promise<void> {
   const pending = [root];
diff --git a/packages/metro-file-map/src/watchers/__tests__/NativeWatcher-test.js b/packages/metro-file-map/src/watchers/__tests__/NativeWatcher-test.js
index b4e936c9d1..7365812c7f 100644
--- a/packages/metro-file-map/src/watchers/__tests__/NativeWatcher-test.js
+++ b/packages/metro-file-map/src/watchers/__tests__/NativeWatcher-test.js
@@ -24,13 +24,13 @@ const ROOT = resolve('/', 'project');
 
 type Deferred<T> = {
   promise: Promise<T>,
-  resolve: T => void,
-  reject: Error => void,
+  resolve: (v: T) => void,
+  reject: (v: Error) => void,
 };
 
 function deferred<T>(): Deferred<T> {
-  let resolve: T => void = () => {};
-  let reject: Error => void = () => {};
+  let resolve: (v: T) => void = () => {};
+  let reject: (v: Error) => void = () => {};
   const promise = new Promise<T>((res, rej) => {
     resolve = res;
     reject = rej;
diff --git a/packages/metro-file-map/src/watchers/__tests__/WatchmanWatcher-test.js b/packages/metro-file-map/src/watchers/__tests__/WatchmanWatcher-test.js
index 02e8aeb925..7850e1f89d 100644
--- a/packages/metro-file-map/src/watchers/__tests__/WatchmanWatcher-test.js
+++ b/packages/metro-file-map/src/watchers/__tests__/WatchmanWatcher-test.js
@@ -31,7 +31,7 @@ const cmdCallback = <T>(err: ?Error, result: Partial<T>): void => {
 // Convenience function to write paths with posix separators but convert them
 // to system separators, and prepend a mock drive letter to absolute paths on
 // Windows.
-const p: string => string = filePath =>
+const p: (v: string) => string = filePath =>
   process.platform === 'win32'
     ? filePath.replaceAll('/', '\\').replace(/^\\/, 'C:\\')
     : filePath;
@@ -39,7 +39,7 @@ const p: string => string = filePath =>
 // Format a posix path as a Watchman-native path on the current platform, i.e.,
 // on Windows, drive letters on absolute paths, but posix-style separators.
 // This should be used for mocking Watchman *output*.
-const wp: string => string = filePath =>
+const wp: (v: string) => string = filePath =>
   process.platform === 'win32' ? filePath.replace(/^\//, 'C:/') : filePath;
 
 jest.mock('fb-watchman', () => ({
diff --git a/packages/metro-resolver/src/__tests__/utils.js b/packages/metro-resolver/src/__tests__/utils.js
index afa235ccc2..9a19328d2a 100644
--- a/packages/metro-resolver/src/__tests__/utils.js
+++ b/packages/metro-resolver/src/__tests__/utils.js
@@ -160,7 +160,7 @@ export function createPackageAccessors(
   };
 }
 
-export const posixToSystemPath: string => string =
+export const posixToSystemPath: (v: string) => string =
   process.platform === 'win32'
     ? filePath => filePath.replaceAll('/', '\\').replace(/^\\/, 'C:\\')
     : filePath => filePath;
diff --git a/packages/metro-runtime/src/modules/__tests__/HMRClient-test.js b/packages/metro-runtime/src/modules/__tests__/HMRClient-test.js
index c9cc5c95ac..76643c8f05 100644
--- a/packages/metro-runtime/src/modules/__tests__/HMRClient-test.js
+++ b/packages/metro-runtime/src/modules/__tests__/HMRClient-test.js
@@ -17,10 +17,10 @@ const HMRClient = require('../HMRClient');
 
 let mockSocket: ?{
   onclose: () => void,
-  onmessage: ({data: string}) => void,
-  onerror: ({data: string}) => void,
+  onmessage: (v: {data: string}) => void,
+  onerror: (v: {data: string}) => void,
   close: () => void,
-  mockEmit: (string, {data: string}) => void,
+  mockEmit: (v0: string, v1: {data: string}) => void,
 } = null;
 let evaledCode = '';
 
diff --git a/packages/metro-runtime/src/modules/asyncRequire.js b/packages/metro-runtime/src/modules/asyncRequire.js
index 400416fdf7..ae1a568797 100644
--- a/packages/metro-runtime/src/modules/asyncRequire.js
+++ b/packages/metro-runtime/src/modules/asyncRequire.js
@@ -10,8 +10,8 @@
  */
 
 type MetroRequire = {
-  (number): unknown,
-  importAll: <T>(number) => T,
+  (v: number): unknown,
+  importAll: <T>(v: number) => T,
   ...
 };
 
diff --git a/packages/metro-runtime/src/polyfills/__tests__/MetroFastRefreshMockRuntime.js b/packages/metro-runtime/src/polyfills/__tests__/MetroFastRefreshMockRuntime.js
index 9e53531b6f..23b71c088a 100644
--- a/packages/metro-runtime/src/polyfills/__tests__/MetroFastRefreshMockRuntime.js
+++ b/packages/metro-runtime/src/polyfills/__tests__/MetroFastRefreshMockRuntime.js
@@ -198,10 +198,10 @@ const moduleSystemCode = (() => {
 // instead of `__ReactRefresh.performFullRefresh`.
 const createModuleSystem: (
   this: any,
-  RuntimeGlobal,
-  boolean,
-  string,
-  void,
+  v0: RuntimeGlobal,
+  v1: boolean,
+  v2: string,
+  v3: void,
 ) => unknown =
   // eslint-disable-next-line no-new-func
   new Function(
diff --git a/packages/metro-runtime/src/polyfills/require.js b/packages/metro-runtime/src/polyfills/require.js
index 4cdeb046bd..2da9533949 100644
--- a/packages/metro-runtime/src/polyfills/require.js
+++ b/packages/metro-runtime/src/polyfills/require.js
@@ -839,8 +839,8 @@ if (__DEV__) {
 
   const topologicalSort = function <T>(
     roots: Array<T>,
-    getEdges: T => Array<T>,
-    earlyStop: T => boolean,
+    getEdges: (v: T) => Array<T>,
+    earlyStop: (v: T) => boolean,
   ): Array<T> {
     const result = [];
     const visited = new Set<unknown>();
diff --git a/packages/metro-source-map/src/Consumer/search.js b/packages/metro-source-map/src/Consumer/search.js
index abb91a5f9a..6fc57fda2a 100644
--- a/packages/metro-source-map/src/Consumer/search.js
+++ b/packages/metro-source-map/src/Consumer/search.js
@@ -12,7 +12,7 @@
 export function greatestLowerBound<T, U>(
   elements: ReadonlyArray<T>,
   target: U,
-  comparator: (U, T) => number,
+  comparator: (v0: U, v1: T) => number,
 ): ?number {
   let first = 0;
   let it = 0;
diff --git a/packages/metro-source-map/src/generateFunctionMap.js b/packages/metro-source-map/src/generateFunctionMap.js
index 75b44bb021..9f3089f05c 100644
--- a/packages/metro-source-map/src/generateFunctionMap.js
+++ b/packages/metro-source-map/src/generateFunctionMap.js
@@ -159,7 +159,7 @@ function functionMapBabelPlugin(): PluginObj<> {
 
 function getFunctionMapVisitor(
   context: ?Context,
-  pushMapping: RangeMapping => void,
+  pushMapping: (v: RangeMapping) => void,
 ): FunctionMapVisitor {
   const nameStack: Array<{loc: BabelNodeSourceLocation, name: string}> = [];
   let tailPos = {line: 1, column: 0};
@@ -223,7 +223,7 @@ function getFunctionMapVisitor(
 function forEachMapping(
   ast: BabelNode,
   context: ?Context,
-  pushMapping: RangeMapping => void,
+  pushMapping: (v: RangeMapping) => void,
 ) {
   const visitor = getFunctionMapVisitor(context, pushMapping);
 
diff --git a/packages/metro-source-map/src/source-map.js b/packages/metro-source-map/src/source-map.js
index 19a354df50..7f911f73ae 100644
--- a/packages/metro-source-map/src/source-map.js
+++ b/packages/metro-source-map/src/source-map.js
@@ -187,7 +187,7 @@ function isVlqMap(
 
 function fromRawMappingsImpl(
   isBlocking: boolean,
-  onDone: Generator => void,
+  onDone: (v: Generator) => void,
   modules: ReadonlyArray<RawMappingsModule>,
   offsetLines: number,
 ): void {
diff --git a/packages/metro-symbolicate/src/GoogleIgnoreListConsumer.js b/packages/metro-symbolicate/src/GoogleIgnoreListConsumer.js
index 6113b3b29b..67c4ec6b0a 100644
--- a/packages/metro-symbolicate/src/GoogleIgnoreListConsumer.js
+++ b/packages/metro-symbolicate/src/GoogleIgnoreListConsumer.js
@@ -14,8 +14,8 @@ import type {BasicSourceMap, IndexMap, MixedSourceMap} from 'metro-source-map';
 import {normalizeSourcePath} from 'metro-source-map';
 
 type SourceNameNormalizer = (
-  string,
-  {readonly sourceRoot?: ?string, ...},
+  v0: string,
+  v1: {readonly sourceRoot?: ?string, ...},
 ) => string;
 
 /**
diff --git a/packages/metro-symbolicate/src/SourceMetadataMapConsumer.js b/packages/metro-symbolicate/src/SourceMetadataMapConsumer.js
index afa22d60f6..cda9a04f93 100644
--- a/packages/metro-symbolicate/src/SourceMetadataMapConsumer.js
+++ b/packages/metro-symbolicate/src/SourceMetadataMapConsumer.js
@@ -35,8 +35,8 @@ type FunctionMapping = {
   ...
 };
 type SourceNameNormalizer = (
-  string,
-  {readonly sourceRoot?: ?string, ...},
+  v0: string,
+  v1: {readonly sourceRoot?: ?string, ...},
 ) => string;
 type MetadataMap = {[source: string]: ?FBSourceMetadata, ...};
 
diff --git a/packages/metro-transform-plugins/src/index.js b/packages/metro-transform-plugins/src/index.js
index 4d4c947f8c..c439c872a9 100644
--- a/packages/metro-transform-plugins/src/index.js
+++ b/packages/metro-transform-plugins/src/index.js
@@ -24,7 +24,7 @@ export type {Options as InlinePluginOptions} from './inline-plugin';
 export type {PluginOptions as InlineRequiresPluginOptions} from './inline-requires-plugin';
 
 type TransformPlugins = {
-  addParamsToDefineCall(string, ...Array<unknown>): string,
+  addParamsToDefineCall(v: string, ...rest: Array<unknown>): string,
   constantFoldingPlugin: ConstantFoldingPlugin,
   importExportPlugin: ImportExportPlugin,
   inlinePlugin: InlinePlugin,
diff --git a/packages/metro/src/Bundler/util.js b/packages/metro/src/Bundler/util.js
index 8d6c2073e1..56e5a49e78 100644
--- a/packages/metro/src/Bundler/util.js
+++ b/packages/metro/src/Bundler/util.js
@@ -124,7 +124,7 @@ export function createRamBundleGroups<T extends ModuleTransportLike>(
 
 function* filter<A extends number, B extends number>(
   iterator: ArrayMap<A, B>,
-  predicate: ([A, Array<B>]) => boolean,
+  predicate: (v: [A, Array<B>]) => boolean,
 ): Generator<[A, Array<B>], void, void> {
   for (const value of iterator) {
     if (predicate(value)) {
diff --git a/packages/metro/src/DeltaBundler/Serializers/getRamBundleInfo.js b/packages/metro/src/DeltaBundler/Serializers/getRamBundleInfo.js
index 1c759593b8..f81ac4f5b8 100644
--- a/packages/metro/src/DeltaBundler/Serializers/getRamBundleInfo.js
+++ b/packages/metro/src/DeltaBundler/Serializers/getRamBundleInfo.js
@@ -30,7 +30,7 @@ type Options = Readonly<{
 }>;
 
 export type RamBundleInfo = {
-  getDependencies: string => Set<string>,
+  getDependencies: (v: string) => Set<string>,
   startupModules: ReadonlyArray<ModuleTransportLike>,
   lazyModules: ReadonlyArray<ModuleTransportLike>,
   groups: Map<number, Set<number>>,
@@ -139,7 +139,7 @@ async function _getRamOptions(
     platform: ?string,
     ...
   },
-  getDependencies: string => Iterable<string>,
+  getDependencies: (v: string) => Iterable<string>,
   getTransformOptions: ?GetTransformOptions,
 ): Promise<
   Readonly<{
diff --git a/packages/metro/src/DeltaBundler/Serializers/helpers/getSourceMapInfo.js b/packages/metro/src/DeltaBundler/Serializers/helpers/getSourceMapInfo.js
index 6f4643e5c5..352ad7a595 100644
--- a/packages/metro/src/DeltaBundler/Serializers/helpers/getSourceMapInfo.js
+++ b/packages/metro/src/DeltaBundler/Serializers/helpers/getSourceMapInfo.js
@@ -22,7 +22,7 @@ export default function getSourceMapInfo(
   module: Module<>,
   options: {
     readonly excludeSource: boolean,
-    readonly shouldAddToIgnoreList: (Module<>) => boolean,
+    readonly shouldAddToIgnoreList: (v: Module<>) => boolean,
     getSourceUrl: ?(module: Module<>) => string,
   },
 ): {
diff --git a/packages/metro/src/DeltaBundler/Serializers/helpers/js.js b/packages/metro/src/DeltaBundler/Serializers/helpers/js.js
index 689788ca73..dab09f90c8 100644
--- a/packages/metro/src/DeltaBundler/Serializers/helpers/js.js
+++ b/packages/metro/src/DeltaBundler/Serializers/helpers/js.js
@@ -31,7 +31,7 @@ import {addParamsToDefineCall} from 'metro-transform-plugins';
 import path from 'node:path';
 
 export type Options = Readonly<{
-  createModuleId: string => number | string,
+  createModuleId: (v: string) => number | string,
   dev: boolean,
   includeAsyncPaths: boolean,
   projectRoot: string,
diff --git a/packages/metro/src/DeltaBundler/Serializers/helpers/processModules.js b/packages/metro/src/DeltaBundler/Serializers/helpers/processModules.js
index d6c02c45a5..174d9556e2 100644
--- a/packages/metro/src/DeltaBundler/Serializers/helpers/processModules.js
+++ b/packages/metro/src/DeltaBundler/Serializers/helpers/processModules.js
@@ -29,7 +29,7 @@ export default function processModules(
     unstable_getAsyncDependencyPath,
   }: Readonly<{
     filter?: (module: Module<>) => boolean,
-    createModuleId: string => number,
+    createModuleId: (v: string) => number,
     dev: boolean,
     includeAsyncPaths: boolean,
     projectRoot: string,
diff --git a/packages/metro/src/DeltaBundler/Serializers/hmrJSBundle.js b/packages/metro/src/DeltaBundler/Serializers/hmrJSBundle.js
index dbb0babe34..62fb82ab3a 100644
--- a/packages/metro/src/DeltaBundler/Serializers/hmrJSBundle.js
+++ b/packages/metro/src/DeltaBundler/Serializers/hmrJSBundle.js
@@ -27,7 +27,7 @@ const debug = debugModule('Metro:HMR');
 
 type Options = Readonly<{
   clientUrl: URL,
-  createModuleId: string => number,
+  createModuleId: (v: string) => number,
   includeAsyncPaths: boolean,
   projectRoot: string,
   serverRoot: string,
diff --git a/packages/metro/src/DeltaBundler/Serializers/sourceMapGenerator.js b/packages/metro/src/DeltaBundler/Serializers/sourceMapGenerator.js
index 41bcf1c830..9ff9908936 100644
--- a/packages/metro/src/DeltaBundler/Serializers/sourceMapGenerator.js
+++ b/packages/metro/src/DeltaBundler/Serializers/sourceMapGenerator.js
@@ -24,7 +24,7 @@ export type SourceMapGeneratorOptions = Readonly<{
 
 function getSourceMapInfosImpl(
   isBlocking: boolean,
-  onDone: (ReadonlyArray<ReturnType<typeof getSourceMapInfo>>) => void,
+  onDone: (v: ReadonlyArray<ReturnType<typeof getSourceMapInfo>>) => void,
   modules: ReadonlyArray<Module<>>,
   options: SourceMapGeneratorOptions,
 ): void {
diff --git a/packages/metro/src/DeltaBundler/Transformer.js b/packages/metro/src/DeltaBundler/Transformer.js
index f7011dd4da..bba83acf90 100644
--- a/packages/metro/src/DeltaBundler/Transformer.js
+++ b/packages/metro/src/DeltaBundler/Transformer.js
@@ -27,9 +27,9 @@ import path from 'node:path';
 
 const debug = debugModule('Metro:Transformer');
 
-type GetOrComputeSha1Fn = string => Promise<
-  Readonly<{content?: Buffer, sha1: string}>,
->;
+type GetOrComputeSha1Fn = (
+  v: string,
+) => Promise<Readonly<{content?: Buffer, sha1: string}>>;
 
 export default class Transformer {
   _config: ConfigT;
diff --git a/packages/metro/src/DeltaBundler/Worker.flow.js b/packages/metro/src/DeltaBundler/Worker.flow.js
index 97447a522f..f373da8321 100644
--- a/packages/metro/src/DeltaBundler/Worker.flow.js
+++ b/packages/metro/src/DeltaBundler/Worker.flow.js
@@ -25,12 +25,12 @@ export type {JsTransformOptions as TransformOptions} from 'metro-transform-worke
 
 type TransformerInterface = {
   transform(
-    JsTransformerConfig,
-    string,
-    string,
-    Buffer,
-    JsTransformOptions,
-    ?string,
+    v0: JsTransformerConfig,
+    v1: string,
+    v2: string,
+    v3: Buffer,
+    v4: JsTransformOptions,
+    v5: ?string,
   ): Promise<TransformResult<>>,
 };
 
diff --git a/packages/metro/src/DeltaBundler/__tests__/Graph-test.js b/packages/metro/src/DeltaBundler/__tests__/Graph-test.js
index 4d6f8a5466..869a687e68 100644
--- a/packages/metro/src/DeltaBundler/__tests__/Graph-test.js
+++ b/packages/metro/src/DeltaBundler/__tests__/Graph-test.js
@@ -469,7 +469,7 @@ Generate the initial dependency graph:
 Paths are given as posix and mapped through `p`, so that tests exercising
 path-sensitive logic can use system paths.
 */
-function setUpInitialGraph(p: string => string) {
+function setUpInitialGraph(p: (v: string) => string) {
   mockedDependencies = new Set();
   mockedDependencyTree = new Map();
 
diff --git a/packages/metro/src/DeltaBundler/__tests__/test-utils.js b/packages/metro/src/DeltaBundler/__tests__/test-utils.js
index 49ab7756f1..1419c96be0 100644
--- a/packages/metro/src/DeltaBundler/__tests__/test-utils.js
+++ b/packages/metro/src/DeltaBundler/__tests__/test-utils.js
@@ -63,7 +63,7 @@ export const createPathNormalizer = (
   platform: 'win32' | 'posix' = process.platform === 'win32'
     ? 'win32'
     : 'posix',
-): (string => string) =>
+): ((v: string) => string) =>
   platform === 'win32'
     ? posixPath => posixPath.replace(/^\//, 'C:\\').replaceAll('/', '\\')
     : posixPath => posixPath;
diff --git a/packages/metro/src/DeltaBundler/buildSubgraph.js b/packages/metro/src/DeltaBundler/buildSubgraph.js
index 05974cc5d6..b3a4a98730 100644
--- a/packages/metro/src/DeltaBundler/buildSubgraph.js
+++ b/packages/metro/src/DeltaBundler/buildSubgraph.js
@@ -27,7 +27,7 @@ import path from 'node:path';
 type Parameters<T> = Readonly<{
   resolve: ResolveFn,
   transform: TransformFn<T>,
-  shouldTraverse: (ResolvedDependency, ?VirtualSource) => boolean,
+  shouldTraverse: (v0: ResolvedDependency, v1: ?VirtualSource) => boolean,
 }>;
 
 // The source hash seen for each virtual module, to catch edges that disagree.
diff --git a/packages/metro/src/DeltaBundler/types.js b/packages/metro/src/DeltaBundler/types.js
index 3320b13b72..dbdd53eeb2 100644
--- a/packages/metro/src/DeltaBundler/types.js
+++ b/packages/metro/src/DeltaBundler/types.js
@@ -158,8 +158,8 @@ export type TransformResultWithSource<T = MixedOutput> = Readonly<{
 }>;
 
 export type TransformFn<T = MixedOutput> = (
-  string,
-  ?VirtualSource,
+  v0: string,
+  v1: ?VirtualSource,
 ) => Promise<TransformResultWithSource<T>>;
 
 export type ResolveFn = (
diff --git a/packages/metro/src/HmrServer.js b/packages/metro/src/HmrServer.js
index 95589a1799..4a5408625d 100644
--- a/packages/metro/src/HmrServer.js
+++ b/packages/metro/src/HmrServer.js
@@ -42,7 +42,7 @@ const {createActionStartEntry, createActionEndEntry, log} = Logger;
 export type Client = {
   optedIntoHMR: boolean,
   revisionIds: Array<RevisionId>,
-  readonly sendFn: string => void,
+  readonly sendFn: (v: string) => void,
 };
 
 type ClientGroup = {
@@ -53,9 +53,9 @@ type ClientGroup = {
   readonly graphOptions: GraphOptions,
 };
 
-function send(sendFns: Array<(string) => void>, message: HmrMessage): void {
+function send(sendFns: Array<(v: string) => void>, message: HmrMessage): void {
   const strMessage = JSON.stringify(message);
-  sendFns.forEach((sendFn: string => void) => sendFn(strMessage));
+  sendFns.forEach((sendFn: (v: string) => void) => sendFn(strMessage));
 }
 
 /**
diff --git a/packages/metro/src/IncrementalBundler.js b/packages/metro/src/IncrementalBundler.js
index 1225d0641f..a8745f2702 100644
--- a/packages/metro/src/IncrementalBundler.js
+++ b/packages/metro/src/IncrementalBundler.js
@@ -349,17 +349,19 @@ export default class IncrementalBundler {
     await Promise.all(
       absoluteEntryFiles.map(
         (entryFile: string) =>
-          new Promise((resolve: void => void, reject: unknown => unknown) => {
-            // This should throw an error if the file doesn't exist.
-            // Using this instead of fs.exists to account for SimLinks.
-            fs.realpath(entryFile, err => {
-              if (err) {
-                reject(new ResourceNotFoundError(entryFile));
-              } else {
-                resolve();
-              }
-            });
-          }),
+          new Promise(
+            (resolve: (v: void) => void, reject: (v: unknown) => unknown) => {
+              // This should throw an error if the file doesn't exist.
+              // Using this instead of fs.exists to account for SimLinks.
+              fs.realpath(entryFile, err => {
+                if (err) {
+                  reject(new ResourceNotFoundError(entryFile));
+                } else {
+                  resolve();
+                }
+              });
+            },
+          ),
       ),
     );
 
diff --git a/packages/metro/src/ModuleGraph/worker/collectDependencies.js b/packages/metro/src/ModuleGraph/worker/collectDependencies.js
index 4610e99893..33ecef3385 100644
--- a/packages/metro/src/ModuleGraph/worker/collectDependencies.js
+++ b/packages/metro/src/ModuleGraph/worker/collectDependencies.js
@@ -96,7 +96,7 @@ export type State = {
   allowOptionalDependencies: AllowOptionalDependencies,
   /** Enable `require.context` statements which can be used to import multiple files in a directory. */
   unstable_allowRequireContext: boolean,
-  unstable_isESMImportAtSource: ?(ReadonlySourceLocation) => boolean,
+  unstable_isESMImportAtSource: ?(v: ReadonlySourceLocation) => boolean,
 };
 
 export type Options = Readonly<{
@@ -109,7 +109,7 @@ export type Options = Readonly<{
   dependencyTransformer?: DependencyTransformer,
   /** Enable `require.context` statements which can be used to import multiple files in a directory. */
   unstable_allowRequireContext: boolean,
-  unstable_isESMImportAtSource?: ?(ReadonlySourceLocation) => boolean,
+  unstable_isESMImportAtSource?: ?(v: ReadonlySourceLocation) => boolean,
 }>;
 
 export type CollectedDependencies = Readonly<{
diff --git a/packages/metro/src/Server.js b/packages/metro/src/Server.js
index b032bcf690..98db21b3ad 100644
--- a/packages/metro/src/Server.js
+++ b/packages/metro/src/Server.js
@@ -604,7 +604,7 @@ export default class Server {
   ) => void = (
     req: IncomingMessage,
     res: ServerResponse,
-    next: (?Error) => void,
+    next: (v: ?Error) => void,
   ) => {
     this._processRequest(req, res, next).catch(next);
   };
@@ -627,7 +627,7 @@ export default class Server {
   async _processRequest(
     req: IncomingMessage,
     res: ServerResponse,
-    next: (?Error) => void,
+    next: (v: ?Error) => void,
   ): Promise<void> {
     const originalUrl = req.url;
     debug('Handling request:    %s', originalUrl);
diff --git a/packages/metro/src/Server/symbolicate.js b/packages/metro/src/Server/symbolicate.js
index f13d351f49..e59ada4a0d 100644
--- a/packages/metro/src/Server/symbolicate.js
+++ b/packages/metro/src/Server/symbolicate.js
@@ -108,7 +108,7 @@ function originalPositionInTuples(
 
 function createFunctionNameGetter(
   module: ExplodedSourceMapModule,
-): Position => ?string {
+): (v: Position) => ?string {
   const consumer = new SourceMetadataMapConsumer(
     {
       version: 3,
@@ -144,7 +144,7 @@ export default async function symbolicate(
       readonly map: Array<MetroSourceMapSegmentTuple> | VlqMap,
       readonly path: string,
     },
-    (Position) => ?string,
+    (v: Position) => ?string,
   >();
 
   function findModule(frame: StackFrameInput): ?ExplodedSourceMapModule {
diff --git a/packages/metro/src/__tests__/HmrServer-test.js b/packages/metro/src/__tests__/HmrServer-test.js
index 70d23172cb..c4c8b7782a 100644
--- a/packages/metro/src/__tests__/HmrServer-test.js
+++ b/packages/metro/src/__tests__/HmrServer-test.js
@@ -169,7 +169,7 @@ describe('HmrServer', () => {
 
     connect = async (
       relativeUrl: string,
-      sendFn?: string => void,
+      sendFn?: (v: string) => void,
       {baseUrl = 'ws://localhost'}: {baseUrl?: string} = {},
     ) => {
       const absoluteUrl = baseUrl + relativeUrl;
@@ -191,7 +191,7 @@ describe('HmrServer', () => {
     message = async (
       client: Client,
       message: HmrClientMessage,
-      sendFn?: string => void,
+      sendFn?: (v: string) => void,
     ) => {
       await hmrServer.onClientMessage(
         client,
diff --git a/packages/metro/src/lib/debounceAsyncQueue.js b/packages/metro/src/lib/debounceAsyncQueue.js
index 51611abe11..73df7e2001 100644
--- a/packages/metro/src/lib/debounceAsyncQueue.js
+++ b/packages/metro/src/lib/debounceAsyncQueue.js
@@ -18,14 +18,14 @@ export default function debounceAsyncQueue<T>(
   let timeout;
   let waiting = false;
   let executing = false;
-  let callbacks: Array<(T) => void> = [];
+  let callbacks: Array<(v: T) => void> = [];
 
   async function execute(): Promise<void> {
     const currentCallbacks = callbacks;
     callbacks = [];
     executing = true;
     const res = await fn();
-    currentCallbacks.forEach((c: T => void) => c(res));
+    currentCallbacks.forEach((c: (v: T) => void) => c(res));
     executing = false;
     if (callbacks.length > 0) {
       await execute();
@@ -33,7 +33,7 @@ export default function debounceAsyncQueue<T>(
   }
 
   return () =>
-    new Promise((resolve: T => void, reject: unknown => void) => {
+    new Promise((resolve: (v: T) => void, reject: (v: unknown) => void) => {
       callbacks.push(resolve);
 
       if (!executing) {
diff --git a/packages/metro/src/lib/getAppendScripts.js b/packages/metro/src/lib/getAppendScripts.js
index 6d5ebd1540..a20121c369 100644
--- a/packages/metro/src/lib/getAppendScripts.js
+++ b/packages/metro/src/lib/getAppendScripts.js
@@ -20,17 +20,17 @@ import nullthrows from 'nullthrows';
 
 type Options<T extends number | string> = Readonly<{
   asyncRequireModulePath: string,
-  createModuleId: string => T,
+  createModuleId: (v: string) => T,
   getRunModuleStatement: (moduleId: T, globalPrefix: string) => string,
   globalPrefix: string,
   inlineSourceMap: ?boolean,
   processModuleFilter: (module: Module<>) => boolean,
   runBeforeMainModule: ReadonlyArray<string>,
   runModule: boolean,
-  shouldAddToIgnoreList: (Module<>) => boolean,
+  shouldAddToIgnoreList: (v: Module<>) => boolean,
   sourceMapUrl: ?string,
   sourceUrl: ?string,
-  getSourceUrl: ?(Module<>) => string,
+  getSourceUrl: ?(v: Module<>) => string,
   ...
 }>;
 
diff --git a/packages/metro/src/lib/pathUtils.js b/packages/metro/src/lib/pathUtils.js
index 68ae29b571..1e2e3ef6de 100644
--- a/packages/metro/src/lib/pathUtils.js
+++ b/packages/metro/src/lib/pathUtils.js
@@ -10,7 +10,7 @@
 
 import * as path from 'node:path';
 
-export const normalizePathSeparatorsToPosix: string => string =
+export const normalizePathSeparatorsToPosix: (v: string) => string =
   path.sep === '/'
     ? filePath => filePath
     : filePath => filePath.replaceAll('\\', '/');
diff --git a/packages/metro/src/shared/output/RamBundle/as-indexed-file.js b/packages/metro/src/shared/output/RamBundle/as-indexed-file.js
index b963c7bcf2..ba4ff703b6 100644
--- a/packages/metro/src/shared/output/RamBundle/as-indexed-file.js
+++ b/packages/metro/src/shared/output/RamBundle/as-indexed-file.js
@@ -96,7 +96,7 @@ function writeBuffers(
   buffers: Array<Buffer>,
 ): Promise<void> {
   buffers.forEach((buffer: Buffer) => stream.write(buffer));
-  return new Promise((resolve: () => void, reject: unknown => unknown) => {
+  return new Promise((resolve: () => void, reject: (v: unknown) => unknown) => {
     stream.on('error', reject);
     stream.on('finish', () => resolve());
     stream.end();
diff --git a/packages/metro/src/shared/output/bundle.flow.js b/packages/metro/src/shared/output/bundle.flow.js
index 122a0f0687..c36abd997d 100644
--- a/packages/metro/src/shared/output/bundle.flow.js
+++ b/packages/metro/src/shared/output/bundle.flow.js
@@ -68,7 +68,7 @@ export async function save(
     ...
   },
   options: OutputOptions,
-  log: string => void,
+  log: (v: string) => void,
 ): Promise<unknown> {
   const {
     bundleOutput,
@@ -101,7 +101,7 @@ export async function save(
   }
 
   // Wait until everything is written to disk.
-  await Promise.all(writeFns.map((cb: void => unknown) => cb()));
+  await Promise.all(writeFns.map((cb: (v: void) => unknown) => cb()));
 }
 
 export const formatName = 'bundle';
diff --git a/private/metro-memory-fs/src/index.js b/private/metro-memory-fs/src/index.js
index 551a63471d..9396f720d3 100644
--- a/private/metro-memory-fs/src/index.js
+++ b/private/metro-memory-fs/src/index.js
@@ -222,7 +222,7 @@ class MemoryFs {
     offset: number,
     length: number,
     position: ?number,
-    callback: (?Error, ?number) => unknown,
+    callback: (v0: ?Error, v1: ?number) => unknown,
   ) => void;
   readFile: (
     filePath: FilePath,
@@ -233,20 +233,20 @@ class MemoryFs {
           ...
         }
       | Encoding
-      | ((?Error, ?Buffer | string) => unknown),
-    callback?: (?Error, ?Buffer | string) => unknown,
+      | ((v0: ?Error, v1: ?Buffer | string) => unknown),
+    callback?: (v0: ?Error, v1: ?Buffer | string) => unknown,
   ) => void;
   realpath: (
     filePath: FilePath,
-    callback: (?Error, ?string) => unknown,
+    callback: (v0: ?Error, v1: ?string) => unknown,
   ) => void;
   write: (
     fd: number,
     bufferOrString: Buffer | string,
-    offsetOrPosition?: number | ((?Error, number) => unknown),
-    lengthOrEncoding?: number | string | ((?Error, number) => unknown),
-    position?: number | ((?Error, number) => unknown),
-    callback?: (?Error, number) => unknown,
+    offsetOrPosition?: number | ((v0: ?Error, v1: number) => unknown),
+    lengthOrEncoding?: number | string | ((v0: ?Error, v1: number) => unknown),
+    position?: number | ((v0: ?Error, v1: number) => unknown),
+    callback?: (v0: ?Error, v1: number) => unknown,
   ) => void;
   writeFile: (
     filePath: FilePath,
@@ -259,8 +259,8 @@ class MemoryFs {
           ...
         }
       | Encoding
-      | ((?Error) => unknown),
-    callback?: (?Error) => unknown,
+      | ((v: ?Error) => unknown),
+    callback?: (v: ?Error) => unknown,
   ) => void;
 
   constructor(options?: ?Options) {
diff --git a/scripts/generateTypeScriptDefinitions.js b/scripts/generateTypeScriptDefinitions.js
index 76d4baac6b..1f63649416 100644
--- a/scripts/generateTypeScriptDefinitions.js
+++ b/scripts/generateTypeScriptDefinitions.js
@@ -419,7 +419,7 @@ function removeDeclareConstAtLine(
 function findBlockStart(
   lines: ReadonlyArray<string>,
   lineIndex: number,
-  predicate: string => boolean,
+  predicate: (v: string) => boolean,
 ): ?number {
   for (let i = lineIndex; i >= 0; i--) {
     if (predicate(lines[i])) {