RCSStaticRouter Breaks React 18 Compatibility

[benquarmby]

The RSCStaticRouter introduced in #13700 makes use of the React.use() hook. This API does not exist in stable versions of React 18 and is only available in React 19 (reference: React 18 docs).

react-router/packages/react-router/lib/rsc/server.ssr.tsx

Lines 102 to 103 in 35718a3

	// @ts-expect-error - need to update the React types
	const payload = React.use(getPayload()) as RSCPayload;

The peer dependency range for react declares compatibility with any version greater than or equal to 18:

react-router/packages/react-router/package.json

Lines 138 to 139 in c3f9f23

	"peerDependencies": {
	"react": ">=18",

This will likely result in runtime problems for apps using React 18. For those bundling with webpack (out of fashion, I know), build time breaks with the following error:

ERROR in ../../node_modules/.pnpm/react-router@7.7.0_react-dom@18.2.0_react@18.2.0__react@18.2.0/node_modules/react-router/dist/development/chunk-T3VM44WY.mjs 2499:18-28
export 'use' (imported as 'React5') was not found in 'react' (possible exports: Children, Component, Fragment, Profiler, PureComponent, StrictMode, Suspense, __SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED, cloneElement, createContext, createElement, createFactory, createRef, forwardRef, isValidElement, lazy, memo, startTransition, unstable_act, useCallback, useContext, useDebugValue, useDeferredValue, useEffect, useId, useImperativeHandle, useInsertionEffect, useLayoutEffect, useMemo, useReducer, useRef, useState, useSyncExternalStore, useTransition, version)