[compiler] Added validation for local state and refined error messages

This PR adds infra to disambiguate between two types of derived state in effects:
  1. State derived from props
  2. State derived from other state

TODO:
- [ ] Props tracking through destructuring and property access does not seem to be propagated correctly inside of Functions' instructions (or i might be misunderstanding how we track aliasing effects)
- [ ] compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/useEffect/invalid-derived-state-from-props-computed.js should be failing
- [ ] Handle "mixed" case where deps flow from at least one prop AND state. Should probably have a different error reason, to aid with categorization

.eslintrc.js

@@ -517,14 +517,6 @@ module.exports = {
         __IS_INTERNAL_VERSION__: 'readonly',
       },
     },
-    {
-      files: ['packages/react-devtools-*/**/*.js'],
-      excludedFiles: '**/__tests__/**/*.js',
-      plugins: ['eslint-plugin-react-hooks-published'],
-      rules: {
-        'react-hooks-published/rules-of-hooks': ERROR,
-      },
-    },
     {
       files: ['packages/eslint-plugin-react-hooks/src/**/*'],
       extends: ['plugin:@typescript-eslint/recommended'],

.github/workflows/compiler_prereleases.yml

@@ -19,9 +19,6 @@ on:
       tag_version:
         required: false
         type: string
-      dry_run:
-        required: false
-        type: boolean
     secrets:
       NPM_TOKEN:
         required: true
@@ -58,13 +55,7 @@ jobs:
           key: compiler-node_modules-v6-${{ runner.arch }}-${{ runner.os }}-${{ hashFiles('compiler/yarn.lock') }}
       - run: yarn install --frozen-lockfile
         if: steps.node_modules.outputs.cache-hit != 'true'
-      - if: inputs.dry_run == true
-        name: Publish packages to npm (dry run)
-        run: |
-          cp ./scripts/release/ci-npmrc ~/.npmrc
-          scripts/release/publish.js --frfr --debug --ci --versionName=${{ inputs.version_name }} --tag=${{ inputs.dist_tag }} ${{ inputs.tag_version && format('--tagVersion={0}', inputs.tag_version) || '' }}
-      - if: inputs.dry_run != true
-        name: Publish packages to npm
+      - name: Publish packages to npm
         run: |
           cp ./scripts/release/ci-npmrc ~/.npmrc
           scripts/release/publish.js --frfr --ci --versionName=${{ inputs.version_name }} --tag=${{ inputs.dist_tag }} ${{ inputs.tag_version && format('--tagVersion={0}', inputs.tag_version) || '' }}

.github/workflows/compiler_prereleases_manual.yml

@@ -17,9 +17,6 @@ on:
       tag_version:
         required: false
         type: string
-      dry_run:
-        required: false
-        type: boolean
 
 permissions: {}
 
@@ -36,6 +33,5 @@ jobs:
       dist_tag: ${{ inputs.dist_tag }}
       version_name: ${{ inputs.version_name }}
       tag_version: ${{ inputs.tag_version }}
-      dry_run: ${{ inputs.dry_run }}
     secrets:
       NPM_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/compiler_prereleases_nightly.yml

@@ -19,6 +19,5 @@ jobs:
       release_channel: experimental
       dist_tag: experimental
       version_name: '0.0.0'
-      dry_run: false
     secrets:
       NPM_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/devtools_discord_notify.yml

@@ -1,49 +0,0 @@
-name: (DevTools) Discord Notify
-
-on:
-  pull_request_target:
-    types: [opened, ready_for_review]
-    paths:
-      - packages/react-devtools**
-      - .github/workflows/devtools_**.yml
-
-permissions: {}
-
-jobs:
-  check_access:
-    if: ${{ github.event.pull_request.draft == false }}
-    runs-on: ubuntu-latest
-    outputs:
-      is_member_or_collaborator: ${{ steps.check_is_member_or_collaborator.outputs.is_member_or_collaborator }}
-    steps:
-      - run: echo ${{ github.event.pull_request.author_association }}
-      - name: Check is member or collaborator
-        id: check_is_member_or_collaborator
-        if: ${{ github.event.pull_request.author_association == 'MEMBER' || github.event.pull_request.author_association == 'COLLABORATOR' }}
-        run: echo "is_member_or_collaborator=true" >> "$GITHUB_OUTPUT"
-
-  check_maintainer:
-    if: ${{ needs.check_access.outputs.is_member_or_collaborator == 'true' || needs.check_access.outputs.is_member_or_collaborator == true }}
-    needs: [check_access]
-    uses: facebook/react/.github/workflows/shared_check_maintainer.yml@main
-    permissions:
-      # Used by check_maintainer
-      contents: read
-    with:
-      actor: ${{ github.event.pull_request.user.login }}
-
-  notify:
-    if: ${{ needs.check_maintainer.outputs.is_core_team == 'true' }}
-    needs: check_maintainer
-    runs-on: ubuntu-latest
-    steps:
-      - name: Discord Webhook Action
-        uses: tsickert/discord-webhook@86dc739f3f165f16dadc5666051c367efa1692f4
-        with:
-          webhook-url: ${{ secrets.DEVTOOLS_DISCORD_WEBHOOK_URL }}
-          embed-author-name: ${{ github.event.pull_request.user.login }}
-          embed-author-url: ${{ github.event.pull_request.user.html_url }}
-          embed-author-icon-url: ${{ github.event.pull_request.user.avatar_url }}
-          embed-title: '#${{ github.event.number }} (+${{github.event.pull_request.additions}} -${{github.event.pull_request.deletions}}): ${{ github.event.pull_request.title }}'
-          embed-description: ${{ github.event.pull_request.body }}
-          embed-url: ${{ github.event.pull_request.html_url }}

.github/workflows/devtools_regression_tests.yml

@@ -92,7 +92,7 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           name: react-devtools
-          path: build/devtools
+          path: build/devtools.tgz
           if-no-files-found: error
       # Simplifies getting the extension for local testing
       - name: Archive chrome extension
@@ -201,5 +201,5 @@ jobs:
       - uses: actions/upload-artifact@v4
         with:
           name: screenshots
-          path: ./tmp/playwright-artifacts
+          path: ./tmp/screenshots
           if-no-files-found: warn

.github/workflows/runtime_build_and_test.yml

@@ -194,7 +194,7 @@ jobs:
         if: steps.node_modules.outputs.cache-hit != 'true'
       - run: |
           yarn generate-inline-fizz-runtime
-          git diff --exit-code || (echo "There was a change to the Fizz runtime. Run \`yarn generate-inline-fizz-runtime\` and check in the result." && false)
+          git diff --quiet || (echo "There was a change to the Fizz runtime. Run `yarn generate-inline-fizz-runtime` and check in the result." && false)
 
   # ----- FEATURE FLAGS -----
   flags:
@@ -567,7 +567,7 @@ jobs:
       - name: Search build artifacts for unminified errors
         run: |
           yarn extract-errors
-          git diff --exit-code || (echo "Found unminified errors. Either update the error codes map or disable error minification for the affected build, if appropriate." && false)
+          git diff --quiet || (echo "Found unminified errors. Either update the error codes map or disable error minification for the affected build, if appropriate." && false)
 
   check_release_dependencies:
     name: Check release dependencies
@@ -766,11 +766,6 @@ jobs:
           name: react-devtools-${{ matrix.browser }}-extension
           path: build/devtools/${{ matrix.browser }}-extension.zip
           if-no-files-found: error
-      - name: Archive ${{ matrix.browser }} metadata
-        uses: actions/upload-artifact@v4
-        with:
-          name: react-devtools-${{ matrix.browser }}-metadata
-          path: build/devtools/webpack-stats.*.json
 
   merge_devtools_artifacts:
     name: Merge DevTools artifacts
@@ -781,7 +776,7 @@ jobs:
         uses: actions/upload-artifact/merge@v4
         with:
           name: react-devtools
-          pattern: react-devtools-*
+          pattern: react-devtools-*-extension
 
   run_devtools_e2e_tests:
     name: Run DevTools e2e tests
@@ -831,12 +826,6 @@ jobs:
       - run: ./scripts/ci/run_devtools_e2e_tests.js
         env:
           RELEASE_CHANNEL: experimental
-      - name: Archive Playwright report
-        uses: actions/upload-artifact@v4
-        with:
-          name: devtools-playwright-artifacts
-          path: tmp/playwright-artifacts
-          if-no-files-found: warn
 
   # ----- SIZEBOT -----
   sizebot:

.github/workflows/runtime_discord_notify.yml

@@ -4,10 +4,8 @@ on:
   pull_request_target:
     types: [opened, ready_for_review]
     paths-ignore:
-      - packages/react-devtools**
       - compiler/**
       - .github/workflows/compiler_**.yml
-      - .github/workflows/devtools**.yml
 
 permissions: {}
 

.github/workflows/runtime_prereleases.yml

@@ -82,6 +82,7 @@ jobs:
         run: |
           scripts/release/publish.js \
             --ci \
+            --skipTests \
             --tags=${{ inputs.dist_tag }} \
             --onlyPackages=${{ inputs.only_packages }} ${{ (inputs.dry && '') || '\'}}
             ${{ inputs.dry && '--dry' || '' }}
@@ -90,10 +91,11 @@ jobs:
         run: |
           scripts/release/publish.js \
             --ci \
+            --skipTests \
             --tags=${{ inputs.dist_tag }} \
             --skipPackages=${{ inputs.skip_packages }} ${{ (inputs.dry && '') || '\'}}
             ${{ inputs.dry && '--dry' || '' }}
-      - if: '${{ !inputs.skip_packages && !inputs.only_packages }}'
+      - if: '${{ !(inputs.skip_packages && inputs.only_packages) }}'
         name: 'Publish all packages'
         run: |
           scripts/release/publish.js \

.gitignore

@@ -23,7 +23,6 @@ chrome-user-data
 .vscode
 *.swp
 *.swo
-/tmp
 
 packages/react-devtools-core/dist
 packages/react-devtools-extensions/chrome/build

CHANGELOG.md

@@ -1,76 +1,3 @@
-## 19.2.0 (October 1st, 2025)
-
-Below is a list of all new features, APIs, and bug fixes.
-
-Read the [React 19.2 release post](https://react.dev/blog/2025/10/01/react-19-2) for more information.
-
-### New React Features
-
-- [`<Activity>`](https://react.dev/reference/react/Activity): A new API to hide and restore the UI and internal state of its children.
-- [`useEffectEvent`](https://react.dev/reference/react/useEffectEvent) is a React Hook that lets you extract non-reactive logic into an [Effect Event](https://react.dev/learn/separating-events-from-effects#declaring-an-effect-event).
-- [`cacheSignal`](https://react.dev/reference/react/cacheSignal) (for RSCs) lets your know when the `cache()` lifetime is over.
-- [React Performance tracks](https://react.dev/reference/dev-tools/react-performance-tracks) appear on the Performance panel’s timeline in your browser developer tools
-
-### New React DOM Features
-
-- Added resume APIs for partial pre-rendering with Web Streams:
-  - [`resume`](https://react.dev/reference/react-dom/server/resume): to resume a prerender to a stream.
-  - [`resumeAndPrerender`](https://react.dev/reference/react-dom/static/resumeAndPrerender): to resume a prerender to HTML.
-- Added resume APIs for partial pre-rendering with Node Streams:
-  - [`resumeToPipeableStream`](https://react.dev/reference/react-dom/server/resumeToPipeableStream): to resume a prerender to a stream.
-  - [`resumeAndPrerenderToNodeStream`](https://react.dev/reference/react-dom/static/resumeAndPrerenderToNodeStream): to resume a prerender to HTML.
-- Updated [`prerender`](https://react.dev/reference/react-dom/static/prerender) APIs to return a `postponed` state that can be passed to the `resume` APIs.
-
-### Notable changes
-
-- React DOM now batches suspense boundary reveals, matching the behavior of client side rendering. This change is especially noticeable when animating the reveal of Suspense boundaries e.g. with the upcoming `<ViewTransition>` Component. React will batch as much reveals as possible before the first paint while trying to hit popular first-contentful paint metrics.
-- Add Node Web Streams (`prerender`, `renderToReadableStream`) to server-side-rendering APIs for Node.js
-- Use underscore instead of `:` IDs generated by useId
-
-### All Changes
-
-#### React
-
-- `<Activity />` was developed over many years, starting before `ClassComponent.setState` (@acdlite @sebmarkbage and many others)
-- Stringify context as "SomeContext" instead of "SomeContext.Provider" (@kassens [#33507](https://github.com/facebook/react/pull/33507))
-- Include stack of cause of React instrumentation errors with `%o` placeholder (@eps1lon [#34198](https://github.com/facebook/react/pull/34198))
-- Fix infinite `useDeferredValue` loop in popstate event (@acdlite [#32821](https://github.com/facebook/react/pull/32821))
-- Fix a bug when an initial value was passed to `useDeferredValue` (@acdlite [#34376](https://github.com/facebook/react/pull/34376))
-- Fix a crash when submitting forms with Client Actions (@sebmarkbage [#33055](https://github.com/facebook/react/pull/33055))
-- Hide/unhide the content of dehydrated suspense boundaries if they resuspend (@sebmarkbage [#32900](https://github.com/facebook/react/pull/32900))
-- Avoid stack overflow on wide trees during Hot Reload (@sophiebits [#34145](https://github.com/facebook/react/pull/34145))
-- Improve Owner and Component stacks in various places (@sebmarkbage, @eps1lon: [#33629](https://github.com/facebook/react/pull/33629), [#33724](https://github.com/facebook/react/pull/33724), [#32735](https://github.com/facebook/react/pull/32735), [#33723](https://github.com/facebook/react/pull/33723))
-- Add `cacheSignal` (@sebmarkbage [#33557](https://github.com/facebook/react/pull/33557))
-
-#### React DOM
-
-- Block on Suspensey Fonts during reveal of server-side-rendered content (@sebmarkbage [#33342](https://github.com/facebook/react/pull/33342))
-- Use underscore instead of `:` for IDs generated by `useId` (@sebmarkbage, @eps1lon: [#32001](https://github.com/facebook/react/pull/32001), [https://github.com/facebook/react/pull/33342](https://github.com/facebook/react/pull/33342)[#33099](https://github.com/facebook/react/pull/33099), [#33422](https://github.com/facebook/react/pull/33422))
-- Stop warning when ARIA 1.3 attributes are used (@Abdul-Omira [#34264](https://github.com/facebook/react/pull/34264))
-- Allow `nonce` to be used on hoistable styles (@Andarist [#32461](https://github.com/facebook/react/pull/32461))
-- Warn for using a React owned node as a Container if it also has text content (@sebmarkbage [#32774](https://github.com/facebook/react/pull/32774))
-- s/HTML/text for for error messages if text hydration mismatches (@rickhanlonii [#32763](https://github.com/facebook/react/pull/32763))
-- Fix a bug with `React.use` inside `React.lazy`\-ed Component (@hi-ogawa [#33941](https://github.com/facebook/react/pull/33941))
-- Enable the `progressiveChunkSize` option for server-side-rendering APIs (@sebmarkbage [#33027](https://github.com/facebook/react/pull/33027))
-- Fix a bug with deeply nested Suspense inside Suspense fallback when server-side-rendering (@gnoff [#33467](https://github.com/facebook/react/pull/33467))
-- Avoid hanging when suspending after aborting while rendering (@gnoff [#34192](https://github.com/facebook/react/pull/34192))
-- Add Node Web Streams to server-side-rendering APIs for Node.js (@sebmarkbage [#33475](https://github.com/facebook/react/pull/33475))
-
-#### React Server Components
-
-- Preload `<img>` and `<link>` using hints before they're rendered (@sebmarkbage [#34604](https://github.com/facebook/react/pull/34604))
-- Log error if production elements are rendered during development (@eps1lon [#34189](https://github.com/facebook/react/pull/34189))
-- Fix a bug when returning a Temporary reference (e.g. a Client Reference) from Server Functions (@sebmarkbage [#34084](https://github.com/facebook/react/pull/34084), @denk0403 [#33761](https://github.com/facebook/react/pull/33761))
-- Pass line/column to `filterStackFrame` (@eps1lon [#33707](https://github.com/facebook/react/pull/33707))
-- Support Async Modules in Turbopack Server References (@lubieowoce [#34531](https://github.com/facebook/react/pull/34531))
-- Add support for .mjs file extension in Webpack (@jennyscript [#33028](https://github.com/facebook/react/pull/33028))
-- Fix a wrong missing key warning (@unstubbable [#34350](https://github.com/facebook/react/pull/34350))
-- Make console log resolve in predictable order (@sebmarkbage [#33665](https://github.com/facebook/react/pull/33665))
-
-#### React Reconciler
-
-- [createContainer](https://github.com/facebook/react/blob/v19.2.0/packages/react-reconciler/src/ReactFiberReconciler.js#L255-L261) and [createHydrationContainer](https://github.com/facebook/react/blob/v19.2.0/packages/react-reconciler/src/ReactFiberReconciler.js#L305-L312) had their parameter order adjusted after `on*` handlers to account for upcoming experimental APIs
-
 ## 19.1.1 (July 28, 2025)
 
 ### React

MAINTAINERS

@@ -1,6 +1,5 @@
 acdlite
 eps1lon
-EugeneChoi4
 gaearon
 gnoff
 unstubbable

ReactVersions.js

@@ -7,18 +7,18 @@
 //
 // The @latest channel uses the version as-is, e.g.:
 //
-//   19.3.0
+//   19.1.0
 //
 // The @canary channel appends additional information, with the scheme
 // <version>-<label>-<commit_sha>, e.g.:
 //
-//   19.3.0-canary-a1c2d3e4
+//   19.1.0-canary-a1c2d3e4
 //
 // The @experimental channel doesn't include a version, only a date and a sha, e.g.:
 //
 //   0.0.0-experimental-241c4467e-20200129
 
-const ReactVersion = '19.3.0';
+const ReactVersion = '19.2.0';
 
 // The label used by the @canary channel. Represents the upcoming release's
 // stability. Most of the time, this will be "canary", but we may temporarily
@@ -33,8 +33,8 @@ const canaryChannelLabel = 'canary';
 const rcNumber = 0;
 
 const stablePackages = {
-  'eslint-plugin-react-hooks': '7.0.0',
-  'jest-react': '0.18.0',
+  'eslint-plugin-react-hooks': '6.1.0',
+  'jest-react': '0.17.0',
   react: ReactVersion,
   'react-art': ReactVersion,
   'react-dom': ReactVersion,
@@ -42,12 +42,12 @@ const stablePackages = {
   'react-server-dom-turbopack': ReactVersion,
   'react-server-dom-parcel': ReactVersion,
   'react-is': ReactVersion,
-  'react-reconciler': '0.34.0',
-  'react-refresh': '0.19.0',
+  'react-reconciler': '0.33.0',
+  'react-refresh': '0.18.0',
   'react-test-renderer': ReactVersion,
-  'use-subscription': '1.13.0',
-  'use-sync-external-store': '1.7.0',
-  scheduler: '0.28.0',
+  'use-subscription': '1.12.0',
+  'use-sync-external-store': '1.6.0',
+  scheduler: '0.27.0',
 };
 
 // These packages do not exist in the @canary or @latest channel, only

compiler/apps/playground/__tests__/e2e/__snapshots__/page.spec.ts/compilationMode-all-output.txt

@@ -1,4 +1,5 @@
-import { c as _c } from "react/compiler-runtime"; // @compilationMode:"all"
+import { c as _c } from "react/compiler-runtime"; // 
+@compilationMode:"all"
 function nonReactFn() {
   const $ = _c(1);
   let t0;

compiler/apps/playground/__tests__/e2e/__snapshots__/page.spec.ts/default-config.txt

@@ -1,5 +0,0 @@
-import type { PluginOptions } from 
-'babel-plugin-react-compiler/dist';
-({
-  //compilationMode: "all"
-} satisfies PluginOptions);

compiler/apps/playground/__tests__/e2e/__snapshots__/page.spec.ts/disableMemoizationForDebugging-output.txt

@@ -1,14 +0,0 @@
-import { c as _c } from "react/compiler-runtime";
-export default function TestComponent(t0) {
-  const $ = _c(2);
-  const { x } = t0;
-  let t1;
-  if ($[0] !== x || true) {
-    t1 = <Button>{x}</Button>;
-    $[0] = x;
-    $[1] = t1;
-  } else {
-    t1 = $[1];
-  }
-  return t1;
-}

compiler/apps/playground/__tests__/e2e/page.spec.ts

@@ -5,9 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {expect, test, type Page} from '@playwright/test';
+import {expect, test} from '@playwright/test';
 import {encodeStore, type Store} from '../../lib/stores';
-import {defaultConfig} from '../../lib/defaultStore';
 import {format} from 'prettier';
 
 function isMonacoLoaded(): boolean {
@@ -21,16 +20,6 @@ function formatPrint(data: Array<string>): Promise<string> {
   return format(data.join(''), {parser: 'babel'});
 }
 
-async function expandConfigs(page: Page): Promise<void> {
-  const expandButton = page.locator('[title="Expand config editor"]');
-  await expandButton.click();
-  await page.waitForSelector('.monaco-editor-config', {state: 'visible'});
-}
-
-const TEST_SOURCE = `export default function TestComponent({ x }) {
-  return <Button>{x}</Button>;
-}`;
-
 const TEST_CASE_INPUTS = [
   {
     name: 'module-scope-use-memo',
@@ -132,9 +121,10 @@ test('editor should open successfully', async ({page}) => {
 
 test('editor should compile from hash successfully', async ({page}) => {
   const store: Store = {
-    source: TEST_SOURCE,
-    config: defaultConfig,
-    showInternals: false,
+    source: `export default function TestComponent({ x }) {
+      return <Button>{x}</Button>;
+    }
+    `,
   };
   const hash = encodeStore(store);
   await page.goto(`/#${hash}`, {waitUntil: 'networkidle'});
@@ -146,7 +136,7 @@ test('editor should compile from hash successfully', async ({page}) => {
     path: 'test-results/01-compiles-from-hash.png',
   });
   const text =
-    (await page.locator('.monaco-editor-output').allInnerTexts()) ?? [];
+    (await page.locator('.monaco-editor').nth(1).allInnerTexts()) ?? [];
   const output = await formatPrint(text);
 
   expect(output).not.toEqual('');
@@ -155,9 +145,10 @@ test('editor should compile from hash successfully', async ({page}) => {
 
 test('reset button works', async ({page}) => {
   const store: Store = {
-    source: TEST_SOURCE,
-    config: defaultConfig,
-    showInternals: false,
+    source: `export default function TestComponent({ x }) {
+      return <Button>{x}</Button>;
+    }
+    `,
   };
   const hash = encodeStore(store);
   await page.goto(`/#${hash}`, {waitUntil: 'networkidle'});
@@ -166,201 +157,33 @@ test('reset button works', async ({page}) => {
   // Reset button works
   page.on('dialog', dialog => dialog.accept());
   await page.getByRole('button', {name: 'Reset'}).click();
-  await expandConfigs(page);
-
   await page.screenshot({
     fullPage: true,
     path: 'test-results/02-reset-button-works.png',
   });
   const text =
-    (await page.locator('.monaco-editor-output').allInnerTexts()) ?? [];
+    (await page.locator('.monaco-editor').nth(1).allInnerTexts()) ?? [];
   const output = await formatPrint(text);
 
-  const configText =
-    (await page.locator('.monaco-editor-config').allInnerTexts()) ?? [];
-  const configOutput = configText.join('');
-
   expect(output).not.toEqual('');
   expect(output).toMatchSnapshot('02-default-output.txt');
-  expect(configOutput).not.toEqual('');
-  expect(configOutput).toMatchSnapshot('default-config.txt');
-});
-
-test('defaults load when only source is in Store', async ({page}) => {
-  // Test for backwards compatibility
-  const partial = {
-    source: TEST_SOURCE,
-  };
-  const hash = encodeStore(partial as Store);
-  await page.goto(`/#${hash}`, {waitUntil: 'networkidle'});
-  await page.waitForFunction(isMonacoLoaded);
-  await expandConfigs(page);
-
-  await page.screenshot({
-    fullPage: true,
-    path: 'test-results/03-missing-defaults.png',
-  });
-
-  // Config editor has default config
-  const configText =
-    (await page.locator('.monaco-editor-config').allInnerTexts()) ?? [];
-  const configOutput = configText.join('');
-
-  expect(configOutput).not.toEqual('');
-  expect(configOutput).toMatchSnapshot('default-config.txt');
-
-  const checkbox = page.locator('label.show-internals');
-  await expect(checkbox).not.toBeChecked();
-  const ssaTab = page.locator('text=SSA');
-  await expect(ssaTab).not.toBeVisible();
-});
-
-test('show internals button toggles correctly', async ({page}) => {
-  await page.goto(`/`, {waitUntil: 'networkidle'});
-  await page.waitForFunction(isMonacoLoaded);
-
-  // show internals should be off
-  const checkbox = page.locator('label.show-internals');
-  await checkbox.click();
-
-  await page.screenshot({
-    fullPage: true,
-    path: 'test-results/04-show-internals-on.png',
-  });
-
-  await expect(checkbox).toBeChecked();
-
-  const ssaTab = page.locator('text=SSA');
-  await expect(ssaTab).toBeVisible();
-});
-
-test('error is displayed when config has syntax error', async ({page}) => {
-  const store: Store = {
-    source: TEST_SOURCE,
-    config: `compilationMode: `,
-    showInternals: false,
-  };
-  const hash = encodeStore(store);
-  await page.goto(`/#${hash}`, {waitUntil: 'networkidle'});
-  await page.waitForFunction(isMonacoLoaded);
-  await expandConfigs(page);
-  await page.screenshot({
-    fullPage: true,
-    path: 'test-results/05-config-syntax-error.png',
-  });
-
-  const text =
-    (await page.locator('.monaco-editor-output').allInnerTexts()) ?? [];
-  const output = text.join('');
-
-  // Remove hidden chars
-  expect(output.replace(/\s+/g, ' ')).toContain('Invalid override format');
-});
-
-test('error is displayed when config has validation error', async ({page}) => {
-  const store: Store = {
-    source: TEST_SOURCE,
-    config: `import type { PluginOptions } from 'babel-plugin-react-compiler/dist';
-
-({
-  compilationMode: "123"
-} satisfies PluginOptions);`,
-    showInternals: false,
-  };
-  const hash = encodeStore(store);
-  await page.goto(`/#${hash}`, {waitUntil: 'networkidle'});
-  await page.waitForFunction(isMonacoLoaded);
-  await expandConfigs(page);
-  await page.screenshot({
-    fullPage: true,
-    path: 'test-results/06-config-validation-error.png',
-  });
-
-  const text =
-    (await page.locator('.monaco-editor-output').allInnerTexts()) ?? [];
-  const output = text.join('');
-
-  expect(output.replace(/\s+/g, ' ')).toContain('Unexpected compilationMode');
-});
-
-test('disableMemoizationForDebugging flag works as expected', async ({
-  page,
-}) => {
-  const store: Store = {
-    source: TEST_SOURCE,
-    config: `import type { PluginOptions } from 'babel-plugin-react-compiler/dist';
-
-({
-  environment: {
-    disableMemoizationForDebugging: true
-  }
-} satisfies PluginOptions);`,
-    showInternals: false,
-  };
-  const hash = encodeStore(store);
-  await page.goto(`/#${hash}`, {waitUntil: 'networkidle'});
-  await page.waitForFunction(isMonacoLoaded);
-  await expandConfigs(page);
-  await page.screenshot({
-    fullPage: true,
-    path: 'test-results/07-config-disableMemoizationForDebugging-flag.png',
-  });
-
-  const text =
-    (await page.locator('.monaco-editor-output').allInnerTexts()) ?? [];
-  const output = await formatPrint(text);
-
-  expect(output).not.toEqual('');
-  expect(output).toMatchSnapshot('disableMemoizationForDebugging-output.txt');
-});
-
-test('error is displayed when source has syntax error', async ({page}) => {
-  const syntaxErrorSource = `function TestComponent(props) {
-  const oops = props.
-  return (
-    <>{oops}</>
-  );
-}`;
-  const store: Store = {
-    source: syntaxErrorSource,
-    config: defaultConfig,
-    showInternals: false,
-  };
-  const hash = encodeStore(store);
-  await page.goto(`/#${hash}`);
-  await page.waitForFunction(isMonacoLoaded);
-  await expandConfigs(page);
-  await page.screenshot({
-    fullPage: true,
-    path: 'test-results/08-source-syntax-error.png',
-  });
-
-  const text =
-    (await page.locator('.monaco-editor-output').allInnerTexts()) ?? [];
-  const output = text.join('');
-
-  expect(output.replace(/\s+/g, ' ')).toContain(
-    'Expected identifier to be defined before being used',
-  );
 });
 
 TEST_CASE_INPUTS.forEach((t, idx) =>
   test(`playground compiles: ${t.name}`, async ({page}) => {
     const store: Store = {
       source: t.input,
-      config: defaultConfig,
-      showInternals: false,
     };
     const hash = encodeStore(store);
     await page.goto(`/#${hash}`, {waitUntil: 'networkidle'});
     await page.waitForFunction(isMonacoLoaded);
     await page.screenshot({
       fullPage: true,
-      path: `test-results/08-0${idx}-${t.name}.png`,
+      path: `test-results/03-0${idx}-${t.name}.png`,
     });
 
     const text =
-      (await page.locator('.monaco-editor-output').allInnerTexts()) ?? [];
+      (await page.locator('.monaco-editor').nth(1).allInnerTexts()) ?? [];
     let output: string;
     if (t.noFormat) {
       output = text.join('');

compiler/apps/playground/app/index.tsx

@@ -0,0 +1,56 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import type {NextPage} from 'next';
+import Head from 'next/head';
+import {SnackbarProvider} from 'notistack';
+import {Editor, Header, StoreProvider} from '../components';
+import MessageSnackbar from '../components/Message';
+
+const Home: NextPage = () => {
+  return (
+    <div className="flex flex-col w-screen h-screen font-light">
+      <Head>
+        <title>
+          {process.env.NODE_ENV === 'development'
+            ? '[DEV] React Compiler Playground'
+            : 'React Compiler Playground'}
+        </title>
+        <meta
+          name="viewport"
+          content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=0"></meta>
+        <link rel="icon" href="/favicon.ico" />
+        <link rel="manifest" href="/site.webmanifest" />
+        <link
+          rel="preload"
+          href="/fonts/Source-Code-Pro-Regular.woff2"
+          as="font"
+          type="font/woff2"
+          crossOrigin="anonymous"
+        />
+        <link
+          rel="preload"
+          href="/fonts/Optimistic_Display_W_Lt.woff2"
+          as="font"
+          type="font/woff2"
+          crossOrigin="anonymous"
+        />
+      </Head>
+      <StoreProvider>
+        <SnackbarProvider
+          preventDuplicate
+          maxSnack={10}
+          Components={{message: MessageSnackbar}}>
+          <Header />
+          <Editor />
+        </SnackbarProvider>
+      </StoreProvider>
+    </div>
+  );
+};
+
+export default Home;

compiler/apps/playground/components/AccordionWindow.tsx

@@ -1,126 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-import {Resizable} from 're-resizable';
-import React, {
-  useId,
-  unstable_ViewTransition as ViewTransition,
-  unstable_addTransitionType as addTransitionType,
-  startTransition,
-} from 'react';
-import {EXPAND_ACCORDION_TRANSITION} from '../lib/transitionTypes';
-
-type TabsRecord = Map<string, React.ReactNode>;
-
-export default function AccordionWindow(props: {
-  defaultTab: string | null;
-  tabs: TabsRecord;
-  tabsOpen: Set<string>;
-  setTabsOpen: (newTab: Set<string>) => void;
-  changedPasses: Set<string>;
-}): React.ReactElement {
-  return (
-    <div className="flex-1 min-w-[550px] sm:min-w-0">
-      <div className="flex flex-row h-full">
-        {Array.from(props.tabs.keys()).map(name => {
-          return (
-            <AccordionWindowItem
-              name={name}
-              key={name}
-              tabs={props.tabs}
-              tabsOpen={props.tabsOpen}
-              setTabsOpen={props.setTabsOpen}
-              hasChanged={props.changedPasses.has(name)}
-            />
-          );
-        })}
-      </div>
-    </div>
-  );
-}
-
-function AccordionWindowItem({
-  name,
-  tabs,
-  tabsOpen,
-  setTabsOpen,
-  hasChanged,
-}: {
-  name: string;
-  tabs: TabsRecord;
-  tabsOpen: Set<string>;
-  setTabsOpen: (newTab: Set<string>) => void;
-  hasChanged: boolean;
-  isFailure: boolean;
-}): React.ReactElement {
-  const id = useId();
-  const isShow = tabsOpen.has(name);
-
-  const transitionName = `accordion-window-item-${id}`;
-
-  const toggleTabs = (): void => {
-    startTransition(() => {
-      addTransitionType(EXPAND_ACCORDION_TRANSITION);
-      const nextState = new Set(tabsOpen);
-      if (nextState.has(name)) {
-        nextState.delete(name);
-      } else {
-        nextState.add(name);
-      }
-      setTabsOpen(nextState);
-    });
-  };
-
-  // Replace spaces with non-breaking spaces
-  const displayName = name.replace(/ /g, '\u00A0');
-
-  return (
-    <div key={name} className="flex flex-row">
-      {isShow ? (
-        <ViewTransition
-          name={transitionName}
-          update={{
-            [EXPAND_ACCORDION_TRANSITION]: 'expand-accordion',
-            default: 'none',
-          }}>
-          <Resizable className="border-r" minWidth={550} enable={{right: true}}>
-            <h2
-              title="Minimize tab"
-              aria-label="Minimize tab"
-              onClick={toggleTabs}
-              className={`p-4 duration-150 ease-in border-b cursor-pointer border-grey-200 ${
-                hasChanged ? 'font-bold' : 'font-light'
-              } text-secondary hover:text-link`}>
-              - {displayName}
-            </h2>
-            {tabs.get(name) ?? <div>No output for {name}</div>}
-          </Resizable>
-        </ViewTransition>
-      ) : (
-        <ViewTransition
-          name={transitionName}
-          update={{
-            [EXPAND_ACCORDION_TRANSITION]: 'expand-accordion',
-            default: 'none',
-          }}>
-          <div className="relative items-center h-full px-1 py-6 align-middle border-r border-grey-200">
-            <button
-              title={`Expand compiler tab: ${name}`}
-              aria-label={`Expand compiler tab: ${name}`}
-              style={{transform: 'rotate(90deg) translate(-50%)'}}
-              onClick={toggleTabs}
-              className={`flex-grow-0 w-5 transition-colors duration-150 ease-in ${
-                hasChanged ? 'font-bold' : 'font-light'
-              } text-secondary hover:text-link`}>
-              {displayName}
-            </button>
-          </div>
-        </ViewTransition>
-      )}
-    </div>
-  );
-}

compiler/apps/playground/components/Editor/ConfigEditor.tsx

@@ -8,93 +8,84 @@
 import MonacoEditor, {loader, type Monaco} from '@monaco-editor/react';
 import type {editor} from 'monaco-editor';
 import * as monaco from 'monaco-editor';
-import React, {
-  useState,
-  useRef,
-  unstable_ViewTransition as ViewTransition,
-  unstable_addTransitionType as addTransitionType,
-  startTransition,
-} from 'react';
+import React, {useState, useCallback} from 'react';
 import {Resizable} from 're-resizable';
+import {useSnackbar} from 'notistack';
 import {useStore, useStoreDispatch} from '../StoreContext';
-import {monacoConfigOptions} from './monacoOptions';
-import {IconChevron} from '../Icons/IconChevron';
-import {CONFIG_PANEL_TRANSITION} from '../../lib/transitionTypes';
+import {monacoOptions} from './monacoOptions';
+import {
+  ConfigError,
+  generateOverridePragmaFromConfig,
+  updateSourceWithOverridePragma,
+} from '../../lib/configUtils';
 
 // @ts-expect-error - webpack asset/source loader handles .d.ts files as strings
 import compilerTypeDefs from 'babel-plugin-react-compiler/dist/index.d.ts';
 
 loader.config({monaco});
 
-export default function ConfigEditor({
-  formattedAppliedConfig,
-}: {
-  formattedAppliedConfig: string;
-}): React.ReactElement {
+export default function ConfigEditor(): React.ReactElement {
   const [isExpanded, setIsExpanded] = useState(false);
-
-  return (
-    // TODO: Use <Activity> when it is compatible with Monaco: https://github.com/suren-atoyan/monaco-react/issues/753
-    <>
-      <div
-        style={{
-          display: isExpanded ? 'block' : 'none',
-        }}>
-        <ExpandedEditor
-          onToggle={() => {
-            startTransition(() => {
-              addTransitionType(CONFIG_PANEL_TRANSITION);
-              setIsExpanded(false);
-            });
-          }}
-          formattedAppliedConfig={formattedAppliedConfig}
-        />
-      </div>
-      <div
-        style={{
-          display: !isExpanded ? 'block' : 'none',
-        }}>
-        <CollapsedEditor
-          onToggle={() => {
-            startTransition(() => {
-              addTransitionType(CONFIG_PANEL_TRANSITION);
-              setIsExpanded(true);
-            });
-          }}
-        />
-      </div>
-    </>
-  );
-}
-
-function ExpandedEditor({
-  onToggle,
-  formattedAppliedConfig,
-}: {
-  onToggle: (expanded: boolean) => void;
-  formattedAppliedConfig: string;
-}): React.ReactElement {
   const store = useStore();
   const dispatchStore = useStoreDispatch();
-  const debounceTimerRef = useRef<NodeJS.Timeout | null>(null);
+  const {enqueueSnackbar} = useSnackbar();
 
-  const handleChange: (value: string | undefined) => void = (
-    value: string | undefined,
-  ) => {
-    if (value === undefined) return;
+  const toggleExpanded = useCallback(() => {
+    setIsExpanded(prev => !prev);
+  }, []);
 
-    if (debounceTimerRef.current) {
-      clearTimeout(debounceTimerRef.current);
-    }
+  const handleApplyConfig: () => Promise<void> = async () => {
+    try {
+      const config = store.config || '';
+
+      if (!config.trim()) {
+        enqueueSnackbar(
+          'Config is empty. Please add configuration options first.',
+          {
+            variant: 'warning',
+          },
+        );
+        return;
+      }
+      const newPragma = await generateOverridePragmaFromConfig(config);
+      const updatedSource = updateSourceWithOverridePragma(
+        store.source,
+        newPragma,
+      );
 
-    debounceTimerRef.current = setTimeout(() => {
       dispatchStore({
-        type: 'updateConfig',
+        type: 'updateFile',
         payload: {
-          config: value,
+          source: updatedSource,
+          config: config,
         },
       });
-    }, 500); // 500ms debounce delay
+    } catch (error) {
+      console.error('Failed to apply config:', error);
+
+      if (error instanceof ConfigError && error.message.trim()) {
+        enqueueSnackbar(error.message, {
+          variant: 'error',
+        });
+      } else {
+        enqueueSnackbar('Unexpected error: failed to apply config.', {
+          variant: 'error',
+        });
+      }
+    }
+  };
+
+  const handleChange: (value: string | undefined) => void = value => {
+    if (value === undefined) return;
+
+    // Only update the config
+    dispatchStore({
+      type: 'updateFile',
+      payload: {
+        source: store.source,
+        config: value,
+      },
+    });
   };
 
   const handleMount: (
@@ -118,98 +109,75 @@ function ExpandedEditor({
       allowSyntheticDefaultImports: true,
       jsx: monaco.languages.typescript.JsxEmit.React,
     });
+
+    const uri = monaco.Uri.parse(`file:///config.ts`);
+    const model = monaco.editor.getModel(uri);
+    if (model) {
+      model.updateOptions({tabSize: 2});
+    }
   };
 
   return (
-    <ViewTransition
-      update={{[CONFIG_PANEL_TRANSITION]: 'slide-in', default: 'none'}}>
-      <Resizable
-        minWidth={300}
-        maxWidth={600}
-        defaultSize={{width: 350}}
-        enable={{right: true, bottom: false}}>
-        <div className="bg-blue-10 relative h-full flex flex-col !h-[calc(100vh_-_3.5rem)] border border-gray-300">
-          <div
-            className="absolute w-8 h-16 bg-blue-10 rounded-r-full flex items-center justify-center z-[2] cursor-pointer border border-l-0 border-gray-300"
-            title="Minimize config editor"
-            onClick={onToggle}
-            style={{
-              top: '50%',
-              marginTop: '-32px',
-              right: '-32px',
-              borderTopLeftRadius: 0,
-              borderBottomLeftRadius: 0,
-            }}>
-            <IconChevron displayDirection="left" className="text-blue-50" />
-          </div>
-
-          <div className="flex-1 flex flex-col m-2 mb-2">
-            <div className="pb-2">
-              <h2 className="inline-block text-blue-50 py-1.5 px-1.5 xs:px-3 sm:px-4 text-sm">
-                Config Overrides
-              </h2>
-            </div>
-            <div className="flex-1 border border-gray-300">
+    <div className="flex flex-row relative">
+      {isExpanded ? (
+        <>
+          <Resizable
+            className="border-r"
+            minWidth={300}
+            maxWidth={600}
+            defaultSize={{width: 350, height: 'auto'}}
+            enable={{right: true}}>
+            <h2
+              title="Minimize config editor"
+              aria-label="Minimize config editor"
+              onClick={toggleExpanded}
+              className="p-4 duration-150 ease-in border-b cursor-pointer border-grey-200 font-light text-secondary hover:text-link">
+              - Config Overrides
+            </h2>
+            <div className="h-[calc(100vh_-_3.5rem_-_4rem)]">
               <MonacoEditor
                 path={'config.ts'}
                 language={'typescript'}
                 value={store.config}
                 onMount={handleMount}
                 onChange={handleChange}
-                loading={''}
-                className="monaco-editor-config"
-                options={monacoConfigOptions}
-              />
-            </div>
-          </div>
-          <div className="flex-1 flex flex-col m-2">
-            <div className="pb-2">
-              <h2 className="inline-block text-blue-50 py-1.5 px-1.5 xs:px-3 sm:px-4 text-sm">
-                Applied Configs
-              </h2>
-            </div>
-            <div className="flex-1 border border-gray-300">
-              <MonacoEditor
-                path={'applied-config.js'}
-                language={'javascript'}
-                value={formattedAppliedConfig}
-                loading={''}
-                className="monaco-editor-applied-config"
                 options={{
-                  ...monacoConfigOptions,
-                  readOnly: true,
+                  ...monacoOptions,
+                  lineNumbers: 'off',
+                  folding: false,
+                  renderLineHighlight: 'none',
+                  scrollBeyondLastLine: false,
+                  hideCursorInOverviewRuler: true,
+                  overviewRulerBorder: false,
+                  overviewRulerLanes: 0,
+                  fontSize: 12,
                 }}
               />
             </div>
-          </div>
+          </Resizable>
+          <button
+            onClick={handleApplyConfig}
+            title="Apply config overrides to input"
+            aria-label="Apply config overrides to input"
+            className="absolute right-0 top-1/2 transform -translate-y-1/2 translate-x-1/2 z-10 w-8 h-8 bg-blue-500 hover:bg-blue-600 text-white rounded-full border-2 border-white shadow-lg flex items-center justify-center text-sm font-medium transition-colors duration-150">
+            →
+          </button>
+        </>
+      ) : (
+        <div className="relative items-center h-full px-1 py-6 align-middle border-r border-grey-200">
+          <button
+            title="Expand config editor"
+            aria-label="Expand config editor"
+            style={{
+              transform: 'rotate(90deg) translate(-50%)',
+              whiteSpace: 'nowrap',
+            }}
+            onClick={toggleExpanded}
+            className="flex-grow-0 w-5 transition-colors duration-150 ease-in font-light text-secondary hover:text-link">
+            Config Overrides
+          </button>
         </div>
-      </Resizable>
-    </ViewTransition>
-  );
-}
-
-function CollapsedEditor({
-  onToggle,
-}: {
-  onToggle: () => void;
-}): React.ReactElement {
-  return (
-    <div
-      className="w-4 !h-[calc(100vh_-_3.5rem)]"
-      style={{position: 'relative'}}>
-      <div
-        className="absolute w-10 h-16 bg-blue-10 hover:translate-x-2 transition-transform rounded-r-full flex items-center justify-center z-[2] cursor-pointer border border-gray-300"
-        title="Expand config editor"
-        onClick={onToggle}
-        style={{
-          top: '50%',
-          marginTop: '-32px',
-          left: '-8px',
-          borderTopLeftRadius: 0,
-          borderBottomLeftRadius: 0,
-        }}>
-        <IconChevron displayDirection="right" className="text-blue-50" />
-      </div>
+      )}
     </div>
   );
 }

compiler/apps/playground/components/Editor/EditorImpl.tsx

@@ -5,30 +5,324 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {
+import {parse as babelParse, ParseResult} from '@babel/parser';
+import * as HermesParser from 'hermes-parser';
+import * as t from '@babel/types';
+import BabelPluginReactCompiler, {
+  CompilerError,
   CompilerErrorDetail,
   CompilerDiagnostic,
+  Effect,
+  ErrorCategory,
+  parseConfigPragmaForTests,
+  ValueKind,
+  type Hook,
+  PluginOptions,
+  CompilerPipelineValue,
+  parsePluginOptions,
+  printReactiveFunctionWithOutlined,
+  printFunctionWithOutlined,
 } from 'babel-plugin-react-compiler';
-import {useDeferredValue, useMemo, useState} from 'react';
-import {useStore} from '../StoreContext';
+import clsx from 'clsx';
+import invariant from 'invariant';
+import {useSnackbar} from 'notistack';
+import {useDeferredValue, useMemo} from 'react';
+import {useMountEffect} from '../../hooks';
+import {defaultStore} from '../../lib/defaultStore';
+import {
+  createMessage,
+  initStoreFromUrlOrLocalStorage,
+  MessageLevel,
+  MessageSource,
+  type Store,
+} from '../../lib/stores';
+import {useStore, useStoreDispatch} from '../StoreContext';
 import ConfigEditor from './ConfigEditor';
 import Input from './Input';
-import {CompilerOutput, default as Output} from './Output';
-import {compile} from '../../lib/compilation';
-import prettyFormat from 'pretty-format';
+import {
+  CompilerOutput,
+  CompilerTransformOutput,
+  default as Output,
+  PrintedCompilerPipelineValue,
+} from './Output';
+import {transformFromAstSync} from '@babel/core';
+import {LoggerEvent} from 'babel-plugin-react-compiler/dist/Entrypoint';
+import {useSearchParams} from 'next/navigation';
+
+function parseInput(
+  input: string,
+  language: 'flow' | 'typescript',
+): ParseResult<t.File> {
+  // Extract the first line to quickly check for custom test directives
+  if (language === 'flow') {
+    return HermesParser.parse(input, {
+      babel: true,
+      flow: 'all',
+      sourceType: 'module',
+      enableExperimentalComponentSyntax: true,
+    });
+  } else {
+    return babelParse(input, {
+      plugins: ['typescript', 'jsx'],
+      sourceType: 'module',
+    }) as ParseResult<t.File>;
+  }
+}
+
+function invokeCompiler(
+  source: string,
+  language: 'flow' | 'typescript',
+  options: PluginOptions,
+): CompilerTransformOutput {
+  const ast = parseInput(source, language);
+  let result = transformFromAstSync(ast, source, {
+    filename: '_playgroundFile.js',
+    highlightCode: false,
+    retainLines: true,
+    plugins: [[BabelPluginReactCompiler, options]],
+    ast: true,
+    sourceType: 'module',
+    configFile: false,
+    sourceMaps: true,
+    babelrc: false,
+  });
+  if (result?.ast == null || result?.code == null || result?.map == null) {
+    throw new Error('Expected successful compilation');
+  }
+  return {
+    code: result.code,
+    sourceMaps: result.map,
+    language,
+  };
+}
+
+const COMMON_HOOKS: Array<[string, Hook]> = [
+  [
+    'useFragment',
+    {
+      valueKind: ValueKind.Frozen,
+      effectKind: Effect.Freeze,
+      noAlias: true,
+      transitiveMixedData: true,
+    },
+  ],
+  [
+    'usePaginationFragment',
+    {
+      valueKind: ValueKind.Frozen,
+      effectKind: Effect.Freeze,
+      noAlias: true,
+      transitiveMixedData: true,
+    },
+  ],
+  [
+    'useRefetchableFragment',
+    {
+      valueKind: ValueKind.Frozen,
+      effectKind: Effect.Freeze,
+      noAlias: true,
+      transitiveMixedData: true,
+    },
+  ],
+  [
+    'useLazyLoadQuery',
+    {
+      valueKind: ValueKind.Frozen,
+      effectKind: Effect.Freeze,
+      noAlias: true,
+      transitiveMixedData: true,
+    },
+  ],
+  [
+    'usePreloadedQuery',
+    {
+      valueKind: ValueKind.Frozen,
+      effectKind: Effect.Freeze,
+      noAlias: true,
+      transitiveMixedData: true,
+    },
+  ],
+];
+
+function compile(
+  source: string,
+  mode: 'compiler' | 'linter',
+): [CompilerOutput, 'flow' | 'typescript'] {
+  const results = new Map<string, Array<PrintedCompilerPipelineValue>>();
+  const error = new CompilerError();
+  const otherErrors: Array<CompilerErrorDetail | CompilerDiagnostic> = [];
+  const upsert: (result: PrintedCompilerPipelineValue) => void = result => {
+    const entry = results.get(result.name);
+    if (Array.isArray(entry)) {
+      entry.push(result);
+    } else {
+      results.set(result.name, [result]);
+    }
+  };
+  let language: 'flow' | 'typescript';
+  if (source.match(/\@flow/)) {
+    language = 'flow';
+  } else {
+    language = 'typescript';
+  }
+  let transformOutput;
+  try {
+    // Extract the first line to quickly check for custom test directives
+    const pragma = source.substring(0, source.indexOf('\n'));
+    const logIR = (result: CompilerPipelineValue): void => {
+      switch (result.kind) {
+        case 'ast': {
+          break;
+        }
+        case 'hir': {
+          upsert({
+            kind: 'hir',
+            fnName: result.value.id,
+            name: result.name,
+            value: printFunctionWithOutlined(result.value),
+          });
+          break;
+        }
+        case 'reactive': {
+          upsert({
+            kind: 'reactive',
+            fnName: result.value.id,
+            name: result.name,
+            value: printReactiveFunctionWithOutlined(result.value),
+          });
+          break;
+        }
+        case 'debug': {
+          upsert({
+            kind: 'debug',
+            fnName: null,
+            name: result.name,
+            value: result.value,
+          });
+          break;
+        }
+        default: {
+          const _: never = result;
+          throw new Error(`Unhandled result ${result}`);
+        }
+      }
+    };
+    const parsedOptions = parseConfigPragmaForTests(pragma, {
+      compilationMode: 'infer',
+      environment:
+        mode === 'linter'
+          ? {
+              // enabled in compiler
+              validateRefAccessDuringRender: false,
+              // enabled in linter
+              validateNoSetStateInRender: true,
+              validateNoSetStateInEffects: true,
+              validateNoJSXInTryStatements: true,
+              validateNoImpureFunctionsInRender: true,
+              validateStaticComponents: true,
+              validateNoFreezingKnownMutableFunctions: true,
+              validateNoVoidUseMemo: true,
+            }
+          : {
+              /* use defaults for compiler mode */
+            },
+    });
+    const opts: PluginOptions = parsePluginOptions({
+      ...parsedOptions,
+      environment: {
+        ...parsedOptions.environment,
+        customHooks: new Map([...COMMON_HOOKS]),
+      },
+      logger: {
+        debugLogIRs: logIR,
+        logEvent: (_filename: string | null, event: LoggerEvent) => {
+          if (event.kind === 'CompileError') {
+            otherErrors.push(event.detail);
+          }
+        },
+      },
+    });
+    transformOutput = invokeCompiler(source, language, opts);
+  } catch (err) {
+    /**
+     * error might be an invariant violation or other runtime error
+     * (i.e. object shape that is not CompilerError)
+     */
+    if (err instanceof CompilerError && err.details.length > 0) {
+      error.merge(err);
+    } else {
+      /**
+       * Handle unexpected failures by logging (to get a stack trace)
+       * and reporting
+       */
+      console.error(err);
+      error.details.push(
+        new CompilerErrorDetail({
+          category: ErrorCategory.Invariant,
+          reason: `Unexpected failure when transforming input! ${err}`,
+          loc: null,
+          suggestions: null,
+        }),
+      );
+    }
+  }
+  // Only include logger errors if there weren't other errors
+  if (!error.hasErrors() && otherErrors.length !== 0) {
+    otherErrors.forEach(e => error.details.push(e));
+  }
+  if (error.hasErrors()) {
+    return [{kind: 'err', results, error}, language];
+  }
+  return [
+    {kind: 'ok', results, transformOutput, errors: error.details},
+    language,
+  ];
+}
 
 export default function Editor(): JSX.Element {
   const store = useStore();
   const deferredStore = useDeferredValue(store);
-  const [compilerOutput, language, appliedOptions] = useMemo(
-    () => compile(deferredStore.source, 'compiler', deferredStore.config),
-    [deferredStore.source, deferredStore.config],
+  const dispatchStore = useStoreDispatch();
+  const {enqueueSnackbar} = useSnackbar();
+  const [compilerOutput, language] = useMemo(
+    () => compile(deferredStore.source, 'compiler'),
+    [deferredStore.source],
   );
   const [linterOutput] = useMemo(
-    () => compile(deferredStore.source, 'linter', deferredStore.config),
-    [deferredStore.source, deferredStore.config],
+    () => compile(deferredStore.source, 'linter'),
+    [deferredStore.source],
   );
-  const [formattedAppliedConfig, setFormattedAppliedConfig] = useState('');
+
+  // TODO: Remove this once the config editor is more stable
+  const searchParams = useSearchParams();
+  const search = searchParams.get('showConfig');
+  const shouldShowConfig = search === 'true';
+
+  useMountEffect(() => {
+    // Initialize store
+    let mountStore: Store;
+    try {
+      mountStore = initStoreFromUrlOrLocalStorage();
+    } catch (e) {
+      invariant(e instanceof Error, 'Only Error may be caught.');
+      enqueueSnackbar(e.message, {
+        variant: 'warning',
+        ...createMessage(
+          'Bad URL - fell back to the default Playground.',
+          MessageLevel.Info,
+          MessageSource.Playground,
+        ),
+      });
+      mountStore = defaultStore;
+    }
+
+    dispatchStore({
+      type: 'setStore',
+      payload: {
+        store: mountStore,
+      },
+    });
+  });
 
   let mergedOutput: CompilerOutput;
   let errors: Array<CompilerErrorDetail | CompilerDiagnostic>;
@@ -42,25 +336,14 @@ export default function Editor(): JSX.Element {
     mergedOutput = compilerOutput;
     errors = compilerOutput.error.details;
   }
-
-  if (appliedOptions) {
-    const formatted = prettyFormat(appliedOptions, {
-      printFunctionName: false,
-      printBasicPrototype: false,
-    });
-    if (formatted !== formattedAppliedConfig) {
-      setFormattedAppliedConfig(formatted);
-    }
-  }
-
   return (
     <>
-      <div className="relative flex top-14">
-        <div className="flex-shrink-0">
-          <ConfigEditor formattedAppliedConfig={formattedAppliedConfig} />
-        </div>
-        <div className="flex flex-1 min-w-0">
+      <div className="relative flex basis top-14">
+        {shouldShowConfig && <ConfigEditor />}
+        <div className={clsx('relative sm:basis-1/4')}>
           <Input language={language} errors={errors} />
+        </div>
+        <div className={clsx('flex sm:flex flex-wrap')}>
           <Output store={deferredStore} compilerOutput={mergedOutput} />
         </div>
       </div>

compiler/apps/playground/components/Editor/Input.tsx

@@ -6,31 +6,23 @@
  */
 
 import MonacoEditor, {loader, type Monaco} from '@monaco-editor/react';
-import {
-  CompilerErrorDetail,
-  CompilerDiagnostic,
-} from 'babel-plugin-react-compiler';
+import {CompilerErrorDetail} from 'babel-plugin-react-compiler';
 import invariant from 'invariant';
 import type {editor} from 'monaco-editor';
 import * as monaco from 'monaco-editor';
-import {
-  useEffect,
-  useState,
-  unstable_ViewTransition as ViewTransition,
-} from 'react';
+import {Resizable} from 're-resizable';
+import {useEffect, useState} from 'react';
 import {renderReactCompilerMarkers} from '../../lib/reactCompilerMonacoDiagnostics';
 import {useStore, useStoreDispatch} from '../StoreContext';
-import TabbedWindow from '../TabbedWindow';
 import {monacoOptions} from './monacoOptions';
-import {CONFIG_PANEL_TRANSITION} from '../../lib/transitionTypes';
-
 // @ts-expect-error TODO: Make TS recognize .d.ts files, in addition to loading them with webpack.
 import React$Types from '../../node_modules/@types/react/index.d.ts';
+import {parseAndFormatConfig} from '../../lib/configUtils.ts';
 
 loader.config({monaco});
 
 type Props = {
-  errors: Array<CompilerErrorDetail | CompilerDiagnostic>;
+  errors: Array<CompilerErrorDetail>;
   language: 'flow' | 'typescript';
 };
 
@@ -51,6 +43,11 @@ export default function Input({errors, language}: Props): JSX.Element {
       details: errors,
       source: store.source,
     });
+    /**
+     * N.B. that `tabSize` is a model property, not an editor property.
+     * So, the tab size has to be set per model.
+     */
+    model.updateOptions({tabSize: 2});
   }, [monaco, errors, store.source]);
 
   useEffect(() => {
@@ -86,10 +83,14 @@ export default function Input({errors, language}: Props): JSX.Element {
   const handleChange: (value: string | undefined) => void = async value => {
     if (!value) return;
 
+    // Parse and format the config
+    const config = await parseAndFormatConfig(value);
+
     dispatchStore({
-      type: 'updateSource',
+      type: 'updateFile',
       payload: {
         source: value,
+        config,
       },
     });
   };
@@ -139,42 +140,30 @@ export default function Input({errors, language}: Props): JSX.Element {
     });
   };
 
-  const editorContent = (
-    <MonacoEditor
-      path={'index.js'}
-      /**
-       * .js and .jsx files are specified to be TS so that Monaco can actually
-       * check their syntax using its TS language service. They are still JS files
-       * due to their extensions, so TS language features don't work.
-       */
-      language={'javascript'}
-      value={store.source}
-      onMount={handleMount}
-      onChange={handleChange}
-      className="monaco-editor-input"
-      options={monacoOptions}
-      loading={''}
-    />
-  );
-
-  const tabs = new Map([['Input', editorContent]]);
-  const [activeTab, setActiveTab] = useState('Input');
-
   return (
-    <ViewTransition
-      update={{
-        [CONFIG_PANEL_TRANSITION]: 'container',
-        default: 'none',
-      }}>
-      <div className="flex-1 min-w-[550px] sm:min-w-0">
-        <div className="flex flex-col h-full !h-[calc(100vh_-_3.5rem)] border-r border-gray-200">
-          <TabbedWindow
-            tabs={tabs}
-            activeTab={activeTab}
-            onTabChange={setActiveTab}
-          />
-        </div>
-      </div>
-    </ViewTransition>
+    <div className="relative flex flex-col flex-none border-r border-gray-200">
+      <Resizable
+        minWidth={650}
+        enable={{right: true}}
+        /**
+         * Restrict MonacoEditor's height, since the config autoLayout:true
+         * will grow the editor to fit within parent element
+         */
+        className="!h-[calc(100vh_-_3.5rem)]">
+        <MonacoEditor
+          path={'index.js'}
+          /**
+           * .js and .jsx files are specified to be TS so that Monaco can actually
+           * check their syntax using its TS language service. They are still JS files
+           * due to their extensions, so TS language features don't work.
+           */
+          language={'javascript'}
+          value={store.source}
+          onMount={handleMount}
+          onChange={handleChange}
+          options={monacoOptions}
+        />
+      </Resizable>
+    </div>
   );
 }

compiler/apps/playground/components/Editor/Output.tsx

@@ -19,38 +19,15 @@ import {
 import parserBabel from 'prettier/plugins/babel';
 import * as prettierPluginEstree from 'prettier/plugins/estree';
 import * as prettier from 'prettier/standalone';
+import {memo, ReactNode, useEffect, useState} from 'react';
 import {type Store} from '../../lib/stores';
-import {
-  memo,
-  ReactNode,
-  use,
-  useState,
-  Suspense,
-  unstable_ViewTransition as ViewTransition,
-  unstable_addTransitionType as addTransitionType,
-  startTransition,
-} from 'react';
-import AccordionWindow from '../AccordionWindow';
 import TabbedWindow from '../TabbedWindow';
 import {monacoOptions} from './monacoOptions';
 import {BabelFileResult} from '@babel/core';
-import {
-  CONFIG_PANEL_TRANSITION,
-  TOGGLE_INTERNALS_TRANSITION,
-  EXPAND_ACCORDION_TRANSITION,
-} from '../../lib/transitionTypes';
-import {LRUCache} from 'lru-cache';
-
 const MemoizedOutput = memo(Output);
 
 export default MemoizedOutput;
 
-export const BASIC_OUTPUT_TAB_NAMES = ['Output', 'SourceMap'];
-
-const tabifyCache = new LRUCache<Store, Promise<Map<string, ReactNode>>>({
-  max: 5,
-});
-
 export type PrintedCompilerPipelineValue =
   | {
       kind: 'hir';
@@ -94,7 +71,7 @@ async function tabify(
   const concattedResults = new Map<string, string>();
   // Concat all top level function declaration results into a single tab for each pass
   for (const [passName, results] of compilerOutput.results) {
-    if (!showInternals && !BASIC_OUTPUT_TAB_NAMES.includes(passName)) {
+    if (!showInternals && passName !== 'Output' && passName !== 'SourceMap') {
       continue;
     }
     for (const result of results) {
@@ -219,25 +196,6 @@ ${code}
   return reorderedTabs;
 }
 
-function tabifyCached(
-  store: Store,
-  compilerOutput: CompilerOutput,
-): Promise<Map<string, ReactNode>> {
-  const cached = tabifyCache.get(store);
-  if (cached) return cached;
-  const result = tabify(store.source, compilerOutput, store.showInternals);
-  tabifyCache.set(store, result);
-  return result;
-}
-
-function Fallback(): JSX.Element {
-  return (
-    <div className="w-full h-monaco_small sm:h-monaco flex items-center justify-center">
-      Loading...
-    </div>
-  );
-}
-
 function utf16ToUTF8(s: string): string {
   return unescape(encodeURIComponent(s));
 }
@@ -251,18 +209,12 @@ function getSourceMapUrl(code: string, map: string): string | null {
 }
 
 function Output({store, compilerOutput}: Props): JSX.Element {
-  return (
-    <Suspense fallback={<Fallback />}>
-      <OutputContent store={store} compilerOutput={compilerOutput} />
-    </Suspense>
-  );
-}
-
-function OutputContent({store, compilerOutput}: Props): JSX.Element {
   const [tabsOpen, setTabsOpen] = useState<Set<string>>(
     () => new Set(['Output']),
   );
-  const [activeTab, setActiveTab] = useState<string>('Output');
+  const [tabs, setTabs] = useState<Map<string, React.ReactNode>>(
+    () => new Map(),
+  );
 
   /*
    * Update the active tab back to the output or errors tab when the compilation state
@@ -271,19 +223,17 @@ function OutputContent({store, compilerOutput}: Props): JSX.Element {
   const [previousOutputKind, setPreviousOutputKind] = useState(
     compilerOutput.kind,
   );
-  const isFailure = compilerOutput.kind !== 'ok';
-
   if (compilerOutput.kind !== previousOutputKind) {
     setPreviousOutputKind(compilerOutput.kind);
-    if (isFailure) {
-      startTransition(() => {
-        addTransitionType(EXPAND_ACCORDION_TRANSITION);
-        setTabsOpen(prev => new Set(prev).add('Output'));
-        setActiveTab('Output');
-      });
-    }
+    setTabsOpen(new Set(['Output']));
   }
 
+  useEffect(() => {
+    tabify(store.source, compilerOutput, store.showInternals).then(tabs => {
+      setTabs(tabs);
+    });
+  }, [store.source, compilerOutput, store.showInternals]);
+
   const changedPasses: Set<string> = new Set(['Output', 'HIR']); // Initial and final passes should always be bold
   let lastResult: string = '';
   for (const [passName, results] of compilerOutput.results) {
@@ -298,40 +248,17 @@ function OutputContent({store, compilerOutput}: Props): JSX.Element {
       lastResult = currResult;
     }
   }
-  const tabs = use(tabifyCached(store, compilerOutput));
-
-  if (!store.showInternals) {
-    return (
-      <ViewTransition
-        update={{
-          [CONFIG_PANEL_TRANSITION]: 'container',
-          [TOGGLE_INTERNALS_TRANSITION]: '',
-          default: 'none',
-        }}>
-        <TabbedWindow
-          tabs={tabs}
-          activeTab={activeTab}
-          onTabChange={setActiveTab}
-        />
-      </ViewTransition>
-    );
-  }
 
   return (
-    <ViewTransition
-      update={{
-        [CONFIG_PANEL_TRANSITION]: 'accordion-container',
-        [TOGGLE_INTERNALS_TRANSITION]: '',
-        default: 'none',
-      }}>
-      <AccordionWindow
+    <>
+      <TabbedWindow
         defaultTab={store.showInternals ? 'HIR' : 'Output'}
         setTabsOpen={setTabsOpen}
         tabsOpen={tabsOpen}
         tabs={tabs}
         changedPasses={changedPasses}
       />
-    </ViewTransition>
+    </>
   );
 }
 
@@ -383,29 +310,20 @@ function TextTabContent({
         <DiffEditor
           original={diff}
           modified={output}
-          loading={''}
           options={{
             ...monacoOptions,
-            scrollbar: {
-              vertical: 'hidden',
-            },
-            dimension: {
-              width: 0,
-              height: 0,
-            },
             readOnly: true,
             lineNumbers: 'off',
             glyphMargin: false,
             // Undocumented see https://github.com/Microsoft/vscode/issues/30795#issuecomment-410998882
-            overviewRulerLanes: 0,
+            lineDecorationsWidth: 0,
+            lineNumbersMinChars: 0,
           }}
         />
       ) : (
         <MonacoEditor
           language={language ?? 'javascript'}
           value={output}
-          loading={''}
-          className="monaco-editor-output"
           options={{
             ...monacoOptions,
             readOnly: true,

compiler/apps/playground/components/Editor/monacoOptions.ts

@@ -29,17 +29,4 @@ export const monacoOptions: Partial<EditorProps['options']> = {
   automaticLayout: true,
   wordWrap: 'on',
   wrappingIndent: 'same',
-
-  tabSize: 2,
-};
-
-export const monacoConfigOptions: Partial<EditorProps['options']> = {
-  ...monacoOptions,
-  lineNumbers: 'off',
-  renderLineHighlight: 'none',
-  overviewRulerBorder: false,
-  overviewRulerLanes: 0,
-  fontSize: 12,
-  scrollBeyondLastLine: false,
-  glyphMargin: false,
 };

compiler/apps/playground/components/Header.tsx

@@ -10,16 +10,11 @@ import {CheckIcon} from '@heroicons/react/solid';
 import clsx from 'clsx';
 import Link from 'next/link';
 import {useSnackbar} from 'notistack';
-import {
-  useState,
-  startTransition,
-  unstable_addTransitionType as addTransitionType,
-} from 'react';
+import {useState} from 'react';
 import {defaultStore} from '../lib/defaultStore';
 import {IconGitHub} from './Icons/IconGitHub';
 import Logo from './Logo';
 import {useStore, useStoreDispatch} from './StoreContext';
-import {TOGGLE_INTERNALS_TRANSITION} from '../lib/transitionTypes';
 
 export default function Header(): JSX.Element {
   const [showCheck, setShowCheck] = useState(false);
@@ -63,16 +58,11 @@ export default function Header(): JSX.Element {
       </div>
       <div className="flex items-center text-[15px] gap-4">
         <div className="flex items-center gap-2">
-          <label className="show-internals relative inline-block w-[34px] h-5">
+          <label className="relative inline-block w-[34px] h-5">
             <input
               type="checkbox"
               checked={store.showInternals}
-              onChange={() =>
-                startTransition(() => {
-                  addTransitionType(TOGGLE_INTERNALS_TRANSITION);
-                  dispatchStore({type: 'toggleInternals'});
-                })
-              }
+              onChange={() => dispatchStore({type: 'toggleInternals'})}
               className="absolute opacity-0 cursor-pointer h-full w-full m-0"
             />
             <span
@@ -82,7 +72,7 @@ export default function Header(): JSX.Element {
                 'before:bg-white before:rounded-full before:transition-transform before:duration-250',
                 'focus-within:shadow-[0_0_1px_#2196F3]',
                 store.showInternals
-                  ? 'bg-link before:translate-x-3.5'
+                  ? 'bg-blue-500 before:translate-x-3.5'
                   : 'bg-gray-300',
               )}></span>
           </label>

compiler/apps/playground/components/Icons/IconChevron.tsx

@@ -1,41 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-import {memo} from 'react';
-
-export const IconChevron = memo<
-  JSX.IntrinsicElements['svg'] & {
-    /**
-     * The direction the arrow should point.
-     */
-    displayDirection: 'right' | 'left';
-  }
->(function IconChevron({className, displayDirection, ...props}) {
-  const rotationClass =
-    displayDirection === 'left' ? 'rotate-90' : '-rotate-90';
-  const classes = className ? `${rotationClass} ${className}` : rotationClass;
-
-  return (
-    <svg
-      className={classes}
-      xmlns="http://www.w3.org/2000/svg"
-      width="20"
-      height="20"
-      viewBox="0 0 20 20"
-      {...props}>
-      <g fill="none" fillRule="evenodd" transform="translate(-446 -398)">
-        <path
-          fill="currentColor"
-          fillRule="nonzero"
-          d="M95.8838835,240.366117 C95.3957281,239.877961 94.6042719,239.877961 94.1161165,240.366117 C93.6279612,240.854272 93.6279612,241.645728 94.1161165,242.133883 L98.6161165,246.633883 C99.1042719,247.122039 99.8957281,247.122039 100.383883,246.633883 L104.883883,242.133883 C105.372039,241.645728 105.372039,240.854272 104.883883,240.366117 C104.395728,239.877961 103.604272,239.877961 103.116117,240.366117 L99.5,243.982233 L95.8838835,240.366117 Z"
-          transform="translate(356.5 164.5)"
-        />
-        <polygon points="446 418 466 418 466 398 446 398" />
-      </g>
-    </svg>
-  );
-});

compiler/apps/playground/components/StoreContext.tsx

@@ -6,14 +6,10 @@
  */
 
 import type {Dispatch, ReactNode} from 'react';
-import {useState, useEffect, useReducer} from 'react';
+import {useEffect, useReducer} from 'react';
 import createContext from '../lib/createContext';
-import {emptyStore, defaultStore} from '../lib/defaultStore';
-import {
-  saveStore,
-  initStoreFromUrlOrLocalStorage,
-  type Store,
-} from '../lib/stores';
+import {emptyStore} from '../lib/defaultStore';
+import {saveStore, type Store} from '../lib/stores';
 
 const StoreContext = createContext<Store>();
 
@@ -34,20 +30,6 @@ export const useStoreDispatch = StoreDispatchContext.useContext;
  */
 export function StoreProvider({children}: {children: ReactNode}): JSX.Element {
   const [store, dispatch] = useReducer(storeReducer, emptyStore);
-  const [isPageReady, setIsPageReady] = useState<boolean>(false);
-
-  useEffect(() => {
-    let mountStore: Store;
-    try {
-      mountStore = initStoreFromUrlOrLocalStorage();
-    } catch (e) {
-      console.error('Failed to initialize store from URL or local storage', e);
-      mountStore = defaultStore;
-    }
-    dispatch({type: 'setStore', payload: {store: mountStore}});
-    setIsPageReady(true);
-  }, []);
-
   useEffect(() => {
     if (store !== emptyStore) {
       saveStore(store);
@@ -57,7 +39,7 @@ export function StoreProvider({children}: {children: ReactNode}): JSX.Element {
   return (
     <StoreContext.Provider value={store}>
       <StoreDispatchContext.Provider value={dispatch}>
-        {isPageReady ? children : null}
+        {children}
       </StoreDispatchContext.Provider>
     </StoreContext.Provider>
   );
@@ -71,14 +53,9 @@ type ReducerAction =
       };
     }
   | {
-      type: 'updateSource';
+      type: 'updateFile';
       payload: {
         source: string;
-      };
-    }
-  | {
-      type: 'updateConfig';
-      payload: {
         config: string;
       };
     }
@@ -92,18 +69,11 @@ function storeReducer(store: Store, action: ReducerAction): Store {
       const newStore = action.payload.store;
       return newStore;
     }
-    case 'updateSource': {
-      const source = action.payload.source;
+    case 'updateFile': {
+      const {source, config} = action.payload;
       const newStore = {
         ...store,
         source,
-      };
-      return newStore;
-    }
-    case 'updateConfig': {
-      const config = action.payload.config;
-      const newStore = {
-        ...store,
         config,
       };
       return newStore;

compiler/apps/playground/components/TabbedWindow.tsx

@@ -4,78 +4,103 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
-import React, {
-  startTransition,
-  useId,
-  unstable_ViewTransition as ViewTransition,
-  unstable_addTransitionType as addTransitionType,
-} from 'react';
-import clsx from 'clsx';
-import {TOGGLE_TAB_TRANSITION} from '../lib/transitionTypes';
 
-export default function TabbedWindow({
-  tabs,
-  activeTab,
-  onTabChange,
-}: {
-  tabs: Map<string, React.ReactNode>;
-  activeTab: string;
-  onTabChange: (tab: string) => void;
+import {Resizable} from 're-resizable';
+import React, {useCallback} from 'react';
+
+type TabsRecord = Map<string, React.ReactNode>;
+
+export default function TabbedWindow(props: {
+  defaultTab: string | null;
+  tabs: TabsRecord;
+  tabsOpen: Set<string>;
+  setTabsOpen: (newTab: Set<string>) => void;
+  changedPasses: Set<string>;
 }): React.ReactElement {
-  const id = useId();
-  const transitionName = `tab-highlight-${id}`;
-
-  const handleTabChange = (tab: string): void => {
-    startTransition(() => {
-      addTransitionType(TOGGLE_TAB_TRANSITION);
-      onTabChange(tab);
-    });
-  };
-
-  return (
-    <div className="flex-1 min-w-[550px] sm:min-w-0">
-      <div className="flex flex-col h-full max-w-full">
-        <div className="flex p-2 flex-shrink-0">
-          {Array.from(tabs.keys()).map(tab => {
-            const isActive = activeTab === tab;
-            return (
-              <button
-                key={tab}
-                onClick={() => handleTabChange(tab)}
-                className={clsx(
-                  'transition-transform py-1.5 px-1.5 xs:px-3 sm:px-4 rounded-full text-sm relative',
-                  isActive ? 'text-link' : 'hover:bg-primary/5',
-                )}>
-                {isActive && (
-                  <ViewTransition
-                    name={transitionName}
-                    enter={{default: 'none'}}
-                    exit={{default: 'none'}}
-                    share={{
-                      [TOGGLE_TAB_TRANSITION]: 'tab-highlight',
-                      default: 'none',
-                    }}
-                    update={{default: 'none'}}>
-                    <div className="absolute inset-0 bg-highlight rounded-full" />
-                  </ViewTransition>
-                )}
-                <ViewTransition
-                  enter={{default: 'none'}}
-                  exit={{default: 'none'}}
-                  update={{
-                    [TOGGLE_TAB_TRANSITION]: 'tab-text',
-                    default: 'none',
-                  }}>
-                  <span className="relative z-1">{tab}</span>
-                </ViewTransition>
-              </button>
-            );
-          })}
-        </div>
-        <div className="flex-1 overflow-hidden w-full h-full">
-          {tabs.get(activeTab)}
-        </div>
+  if (props.tabs.size === 0) {
+    return (
+      <div
+        className="flex items-center justify-center"
+        style={{width: 'calc(100vw - 650px)'}}>
+        No compiler output detected, see errors below
       </div>
+    );
+  }
+  return (
+    <div className="flex flex-row">
+      {Array.from(props.tabs.keys()).map(name => {
+        return (
+          <TabbedWindowItem
+            name={name}
+            key={name}
+            tabs={props.tabs}
+            tabsOpen={props.tabsOpen}
+            setTabsOpen={props.setTabsOpen}
+            hasChanged={props.changedPasses.has(name)}
+          />
+        );
+      })}
+    </div>
+  );
+}
+
+function TabbedWindowItem({
+  name,
+  tabs,
+  tabsOpen,
+  setTabsOpen,
+  hasChanged,
+}: {
+  name: string;
+  tabs: TabsRecord;
+  tabsOpen: Set<string>;
+  setTabsOpen: (newTab: Set<string>) => void;
+  hasChanged: boolean;
+}): React.ReactElement {
+  const isShow = tabsOpen.has(name);
+
+  const toggleTabs = useCallback(() => {
+    const nextState = new Set(tabsOpen);
+    if (nextState.has(name)) {
+      nextState.delete(name);
+    } else {
+      nextState.add(name);
+    }
+    setTabsOpen(nextState);
+  }, [tabsOpen, name, setTabsOpen]);
+
+  // Replace spaces with non-breaking spaces
+  const displayName = name.replace(/ /g, '\u00A0');
+
+  return (
+    <div key={name} className="flex flex-row">
+      {isShow ? (
+        <Resizable className="border-r" minWidth={550} enable={{right: true}}>
+          <h2
+            title="Minimize tab"
+            aria-label="Minimize tab"
+            onClick={toggleTabs}
+            className={`p-4 duration-150 ease-in border-b cursor-pointer border-grey-200 ${
+              hasChanged ? 'font-bold' : 'font-light'
+            } text-secondary hover:text-link`}>
+            - {displayName}
+          </h2>
+          {tabs.get(name) ?? <div>No output for {name}</div>}
+        </Resizable>
+      ) : (
+        <div className="relative items-center h-full px-1 py-6 align-middle border-r border-grey-200">
+          <button
+            title={`Expand compiler tab: ${name}`}
+            aria-label={`Expand compiler tab: ${name}`}
+            style={{transform: 'rotate(90deg) translate(-50%)'}}
+            onClick={toggleTabs}
+            className={`flex-grow-0 w-5 transition-colors duration-150 ease-in ${
+              hasChanged ? 'font-bold' : 'font-light'
+            } text-secondary hover:text-link`}>
+            {displayName}
+          </button>
+        </div>
+      )}
     </div>
   );
 }

compiler/apps/playground/lib/compilation.ts

@@ -1,308 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-import {parse as babelParse, ParseResult} from '@babel/parser';
-import * as HermesParser from 'hermes-parser';
-import * as t from '@babel/types';
-import BabelPluginReactCompiler, {
-  CompilerError,
-  CompilerErrorDetail,
-  CompilerDiagnostic,
-  Effect,
-  ErrorCategory,
-  parseConfigPragmaForTests,
-  ValueKind,
-  type Hook,
-  PluginOptions,
-  CompilerPipelineValue,
-  parsePluginOptions,
-  printReactiveFunctionWithOutlined,
-  printFunctionWithOutlined,
-  type LoggerEvent,
-} from 'babel-plugin-react-compiler';
-import {transformFromAstSync} from '@babel/core';
-import type {
-  CompilerOutput,
-  CompilerTransformOutput,
-  PrintedCompilerPipelineValue,
-} from '../components/Editor/Output';
-
-function parseInput(
-  input: string,
-  language: 'flow' | 'typescript',
-): ParseResult<t.File> {
-  // Extract the first line to quickly check for custom test directives
-  if (language === 'flow') {
-    return HermesParser.parse(input, {
-      babel: true,
-      flow: 'all',
-      sourceType: 'module',
-      enableExperimentalComponentSyntax: true,
-    });
-  } else {
-    return babelParse(input, {
-      plugins: ['typescript', 'jsx'],
-      sourceType: 'module',
-    }) as ParseResult<t.File>;
-  }
-}
-
-function invokeCompiler(
-  source: string,
-  language: 'flow' | 'typescript',
-  options: PluginOptions,
-): CompilerTransformOutput {
-  const ast = parseInput(source, language);
-  let result = transformFromAstSync(ast, source, {
-    filename: '_playgroundFile.js',
-    highlightCode: false,
-    retainLines: true,
-    plugins: [[BabelPluginReactCompiler, options]],
-    ast: true,
-    sourceType: 'module',
-    configFile: false,
-    sourceMaps: true,
-    babelrc: false,
-  });
-  if (result?.ast == null || result?.code == null || result?.map == null) {
-    throw new Error('Expected successful compilation');
-  }
-  return {
-    code: result.code,
-    sourceMaps: result.map,
-    language,
-  };
-}
-
-const COMMON_HOOKS: Array<[string, Hook]> = [
-  [
-    'useFragment',
-    {
-      valueKind: ValueKind.Frozen,
-      effectKind: Effect.Freeze,
-      noAlias: true,
-      transitiveMixedData: true,
-    },
-  ],
-  [
-    'usePaginationFragment',
-    {
-      valueKind: ValueKind.Frozen,
-      effectKind: Effect.Freeze,
-      noAlias: true,
-      transitiveMixedData: true,
-    },
-  ],
-  [
-    'useRefetchableFragment',
-    {
-      valueKind: ValueKind.Frozen,
-      effectKind: Effect.Freeze,
-      noAlias: true,
-      transitiveMixedData: true,
-    },
-  ],
-  [
-    'useLazyLoadQuery',
-    {
-      valueKind: ValueKind.Frozen,
-      effectKind: Effect.Freeze,
-      noAlias: true,
-      transitiveMixedData: true,
-    },
-  ],
-  [
-    'usePreloadedQuery',
-    {
-      valueKind: ValueKind.Frozen,
-      effectKind: Effect.Freeze,
-      noAlias: true,
-      transitiveMixedData: true,
-    },
-  ],
-];
-
-function parseOptions(
-  source: string,
-  mode: 'compiler' | 'linter',
-  configOverrides: string,
-): PluginOptions {
-  // Extract the first line to quickly check for custom test directives
-  const pragma = source.substring(0, source.indexOf('\n'));
-
-  const parsedPragmaOptions = parseConfigPragmaForTests(pragma, {
-    compilationMode: 'infer',
-    environment:
-      mode === 'linter'
-        ? {
-            // enabled in compiler
-            validateRefAccessDuringRender: false,
-            // enabled in linter
-            validateNoSetStateInRender: true,
-            validateNoSetStateInEffects: true,
-            validateNoJSXInTryStatements: true,
-            validateNoImpureFunctionsInRender: true,
-            validateStaticComponents: true,
-            validateNoFreezingKnownMutableFunctions: true,
-            validateNoVoidUseMemo: true,
-          }
-        : {
-            /* use defaults for compiler mode */
-          },
-  });
-
-  // Parse config overrides from config editor
-  let configOverrideOptions: any = {};
-  const configMatch = configOverrides.match(/^\s*import.*?\n\n\((.*)\)/s);
-  if (configOverrides.trim()) {
-    if (configMatch && configMatch[1]) {
-      const configString = configMatch[1].replace(/satisfies.*$/, '').trim();
-      configOverrideOptions = new Function(`return (${configString})`)();
-    } else {
-      throw new Error('Invalid override format');
-    }
-  }
-
-  const opts: PluginOptions = parsePluginOptions({
-    ...parsedPragmaOptions,
-    ...configOverrideOptions,
-    environment: {
-      ...parsedPragmaOptions.environment,
-      ...configOverrideOptions.environment,
-      customHooks: new Map([...COMMON_HOOKS]),
-    },
-  });
-
-  return opts;
-}
-
-export function compile(
-  source: string,
-  mode: 'compiler' | 'linter',
-  configOverrides: string,
-): [CompilerOutput, 'flow' | 'typescript', PluginOptions | null] {
-  const results = new Map<string, Array<PrintedCompilerPipelineValue>>();
-  const error = new CompilerError();
-  const otherErrors: Array<CompilerErrorDetail | CompilerDiagnostic> = [];
-  const upsert: (result: PrintedCompilerPipelineValue) => void = result => {
-    const entry = results.get(result.name);
-    if (Array.isArray(entry)) {
-      entry.push(result);
-    } else {
-      results.set(result.name, [result]);
-    }
-  };
-  let language: 'flow' | 'typescript';
-  if (source.match(/\@flow/)) {
-    language = 'flow';
-  } else {
-    language = 'typescript';
-  }
-  let transformOutput;
-
-  let baseOpts: PluginOptions | null = null;
-  try {
-    baseOpts = parseOptions(source, mode, configOverrides);
-  } catch (err) {
-    error.details.push(
-      new CompilerErrorDetail({
-        category: ErrorCategory.Config,
-        reason: `Unexpected failure when transforming configs! \n${err}`,
-        loc: null,
-        suggestions: null,
-      }),
-    );
-  }
-  if (baseOpts) {
-    try {
-      const logIR = (result: CompilerPipelineValue): void => {
-        switch (result.kind) {
-          case 'ast': {
-            break;
-          }
-          case 'hir': {
-            upsert({
-              kind: 'hir',
-              fnName: result.value.id,
-              name: result.name,
-              value: printFunctionWithOutlined(result.value),
-            });
-            break;
-          }
-          case 'reactive': {
-            upsert({
-              kind: 'reactive',
-              fnName: result.value.id,
-              name: result.name,
-              value: printReactiveFunctionWithOutlined(result.value),
-            });
-            break;
-          }
-          case 'debug': {
-            upsert({
-              kind: 'debug',
-              fnName: null,
-              name: result.name,
-              value: result.value,
-            });
-            break;
-          }
-          default: {
-            const _: never = result;
-            throw new Error(`Unhandled result ${result}`);
-          }
-        }
-      };
-      // Add logger options to the parsed options
-      const opts = {
-        ...baseOpts,
-        logger: {
-          debugLogIRs: logIR,
-          logEvent: (_filename: string | null, event: LoggerEvent): void => {
-            if (event.kind === 'CompileError') {
-              otherErrors.push(event.detail);
-            }
-          },
-        },
-      };
-      transformOutput = invokeCompiler(source, language, opts);
-    } catch (err) {
-      /**
-       * error might be an invariant violation or other runtime error
-       * (i.e. object shape that is not CompilerError)
-       */
-      if (err instanceof CompilerError && err.details.length > 0) {
-        error.merge(err);
-      } else {
-        /**
-         * Handle unexpected failures by logging (to get a stack trace)
-         * and reporting
-         */
-        error.details.push(
-          new CompilerErrorDetail({
-            category: ErrorCategory.Invariant,
-            reason: `Unexpected failure when transforming input! \n${err}`,
-            loc: null,
-            suggestions: null,
-          }),
-        );
-      }
-    }
-  }
-  // Only include logger errors if there weren't other errors
-  if (!error.hasErrors() && otherErrors.length !== 0) {
-    otherErrors.forEach(e => error.details.push(e));
-  }
-  if (error.hasErrors() || !transformOutput) {
-    return [{kind: 'err', results, error}, language, baseOpts];
-  }
-  return [
-    {kind: 'ok', results, transformOutput, errors: error.details},
-    language,
-    baseOpts,
-  ];
-}

compiler/apps/playground/lib/configUtils.ts

@@ -0,0 +1,120 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import parserBabel from 'prettier/plugins/babel';
+import prettierPluginEstree from 'prettier/plugins/estree';
+import * as prettier from 'prettier/standalone';
+import {parsePluginOptions} from 'babel-plugin-react-compiler';
+import {parseConfigPragmaAsString} from '../../../packages/babel-plugin-react-compiler/src/Utils/TestUtils';
+
+export class ConfigError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = 'ConfigError';
+  }
+}
+/**
+ * Parse config from pragma and format it with prettier
+ */
+export async function parseAndFormatConfig(source: string): Promise<string> {
+  const pragma = source.substring(0, source.indexOf('\n'));
+  let configString = parseConfigPragmaAsString(pragma);
+  if (configString !== '') {
+    configString = `\
+    import type { PluginOptions } from 'babel-plugin-react-compiler/dist';
+
+    (${configString} satisfies Partial<PluginOptions>)`;
+  }
+
+  try {
+    const formatted = await prettier.format(configString, {
+      semi: true,
+      parser: 'babel-ts',
+      plugins: [parserBabel, prettierPluginEstree],
+    });
+    return formatted;
+  } catch (error) {
+    console.error('Error formatting config:', error);
+    return ''; // Return empty string if not valid for now
+  }
+}
+
+function extractCurlyBracesContent(input: string): string {
+  const startIndex = input.indexOf('({') + 1;
+  const endIndex = input.lastIndexOf('}');
+  if (startIndex === -1 || endIndex === -1 || endIndex <= startIndex) {
+    throw new Error('No outer curly braces found in input.');
+  }
+  return input.slice(startIndex, endIndex + 1);
+}
+
+function cleanContent(content: string): string {
+  return content
+    .replace(/[\r\n]+/g, ' ')
+    .replace(/\s+/g, ' ')
+    .trim();
+}
+
+/**
+ * Validate that a config string can be parsed as a valid PluginOptions object
+ * Throws an error if validation fails.
+ */
+function validateConfigAsPluginOptions(configString: string): void {
+  // Validate that config can be parse as JS obj
+  let parsedConfig: unknown;
+  try {
+    parsedConfig = new Function(`return (${configString})`)();
+  } catch (_) {
+    throw new ConfigError('Config has invalid syntax.');
+  }
+
+  // Validate against PluginOptions schema
+  try {
+    parsePluginOptions(parsedConfig);
+  } catch (_) {
+    throw new ConfigError('Config does not match the expected schema.');
+  }
+}
+
+/**
+ * Generate a the override pragma comment from a formatted config object string
+ */
+export async function generateOverridePragmaFromConfig(
+  formattedConfigString: string,
+): Promise<string> {
+  const content = extractCurlyBracesContent(formattedConfigString);
+  const cleanConfig = cleanContent(content);
+
+  validateConfigAsPluginOptions(cleanConfig);
+
+  // Format the config to ensure it's valid
+  await prettier.format(`(${cleanConfig})`, {
+    semi: false,
+    parser: 'babel-ts',
+    plugins: [parserBabel, prettierPluginEstree],
+  });
+
+  return `// @OVERRIDE:${cleanConfig}`;
+}
+
+/**
+ * Update the override pragma comment in source code.
+ */
+export function updateSourceWithOverridePragma(
+  source: string,
+  newPragma: string,
+): string {
+  const firstLineEnd = source.indexOf('\n');
+  const firstLine = source.substring(0, firstLineEnd);
+
+  const pragmaRegex = /^\/\/\s*@/;
+  if (firstLineEnd !== -1 && pragmaRegex.test(firstLine.trim())) {
+    return newPragma + source.substring(firstLineEnd);
+  } else {
+    return newPragma + '\n' + source;
+  }
+}

compiler/apps/playground/lib/defaultStore.ts

@@ -17,8 +17,23 @@ export const defaultConfig = `\
 import type { PluginOptions } from 'babel-plugin-react-compiler/dist';
 
 ({
-  //compilationMode: "all"
-} satisfies PluginOptions);`;
+  compilationMode: 'infer',
+  panicThreshold: 'none',
+  environment: {},
+  logger: null,
+  gating: null,
+  noEmit: false,
+  dynamicGating: null,
+  eslintSuppressionRules: null,
+  flowSuppressions: true,
+  ignoreUseNoForget: false,
+  sources: filename => {
+    return filename.indexOf('node_modules') === -1;
+  },
+  enableReanimatedCheck: true,
+  customOptOutDirectives: null,
+  target: '19',
+} satisfies Partial<PluginOptions>);`;
 
 export const defaultStore: Store = {
   source: index,

compiler/apps/playground/lib/stores/store.ts

@@ -71,7 +71,7 @@ export function initStoreFromUrlOrLocalStorage(): Store {
   // Make sure all properties are populated
   return {
     source: raw.source,
-    config: 'config' in raw && raw['config'] ? raw.config : defaultConfig,
+    config: 'config' in raw ? raw.config : defaultConfig,
     showInternals: 'showInternals' in raw ? raw.showInternals : false,
   };
 }

compiler/apps/playground/lib/transitionTypes.ts

@@ -1,11 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-export const CONFIG_PANEL_TRANSITION = 'config-panel';
-export const TOGGLE_TAB_TRANSITION = 'toggle-tab';
-export const TOGGLE_INTERNALS_TRANSITION = 'toggle-internals';
-export const EXPAND_ACCORDION_TRANSITION = 'open-accordion';

compiler/apps/playground/next-env.d.ts

@@ -1,6 +1,6 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/types/routes.d.ts";
+/// <reference path="./.next/types/routes.d.ts" />
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

compiler/apps/playground/next.config.js

@@ -11,7 +11,6 @@ const path = require('path');
 const nextConfig = {
   experimental: {
     reactCompiler: true,
-    viewTransition: true,
   },
   reactStrictMode: true,
   webpack: (config, options) => {

compiler/apps/playground/package.json

@@ -32,10 +32,9 @@
     "hermes-eslint": "^0.25.0",
     "hermes-parser": "^0.25.0",
     "invariant": "^2.2.4",
-    "lru-cache": "^11.2.2",
     "lz-string": "^1.5.0",
     "monaco-editor": "^0.52.0",
-    "next": "15.6.0-canary.7",
+    "next": "15.5.2",
     "notistack": "^3.0.0-alpha.7",
     "prettier": "^3.3.3",
     "pretty-format": "^29.3.1",
@@ -45,7 +44,7 @@
   },
   "devDependencies": {
     "@types/node": "18.11.9",
-    "@types/react": "19.1.13",
+    "@types/react": "19.1.12",
     "@types/react-dom": "19.1.9",
     "autoprefixer": "^10.4.13",
     "clsx": "^1.2.1",

compiler/apps/playground/playwright.config.js

@@ -55,16 +55,12 @@ export default defineConfig({
     // contextOptions: {
     //   ignoreHTTPSErrors: true,
     // },
-    viewport: {width: 1920, height: 1080},
   },
 
   projects: [
     {
       name: 'chromium',
-      use: {
-        ...devices['Desktop Chrome'],
-        viewport: {width: 1920, height: 1080},
-      },
+      use: {...devices['Desktop Chrome']},
     },
     // {
     //   name: 'Desktop Firefox',

compiler/apps/playground/styles/globals.css

@@ -69,66 +69,3 @@
     scrollbar-width: none; /* Firefox */
   }
 }
-
-::view-transition-old(.slide-in) {
-  animation-name: slideOutLeft;
-}
-::view-transition-new(.slide-in) {
-  animation-name: slideInLeft;
-}
-::view-transition-group(.slide-in) {
-  z-index: 1;
-}
-
-@keyframes slideOutLeft {
-  from {
-    transform: translateX(0);
-  }
-  to {
-    transform: translateX(-100%);
-  }
-}
-@keyframes slideInLeft {
-  from {
-    transform: translateX(-100%);
-  }
-  to {
-    transform: translateX(0);
-  }
-}
-
-::view-transition-old(.container),
-::view-transition-new(.container) {
-  height: 100%;
-}
-
-::view-transition-old(.accordion-container),
-::view-transition-new(.accordion-container) {
-  height: 100%;
-  object-fit: none;
-  object-position: left;
-}
-
-::view-transition-old(.tab-highlight),
-::view-transition-new(.tab-highlight) {
-  height: 100%;
-}
-::view-transition-group(.tab-text) {
-	z-index: 1;
-}
-
-::view-transition-old(.expand-accordion),
-::view-transition-new(.expand-accordion) {
-  width: auto;
-}
-::view-transition-group(.expand-accordion) {
-  overflow: clip;
-}
-
-/**
- * For some reason, the original Monaco editor is still visible to the
- * left of the DiffEditor. This is a workaround for better visual clarity.
- */
-.monaco-diff-editor .editor.original{
-  visibility: hidden !important;
-}

compiler/apps/playground/tsconfig.json

@@ -6,9 +6,6 @@
       "dom.iterable",
       "esnext"
     ],
-    "types": [
-      "react/experimental"
-    ],
     "allowJs": true,
     "skipLibCheck": true,
     "strict": true,
@@ -19,7 +16,7 @@
     "moduleResolution": "node",
     "resolveJsonModule": true,
     "isolatedModules": true,
-    "jsx": "react-jsx",
+    "jsx": "preserve",
     "incremental": true,
     "plugins": [
       {

compiler/apps/playground/yarn.lock

@@ -715,10 +715,10 @@
   dependencies:
     "@monaco-editor/loader" "^1.4.0"
 
-"@next/env@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/env/-/env-15.6.0-canary.7.tgz#cdbf2967a9437ef09eef755e203f315acc4d8d8f"
-  integrity sha512-LNZ7Yd3Cl9rKvjYdeJmszf2HmSDP76SQmfafKep2Ux16ZXKoN5OjwVHFTltKNdsB3vt2t+XJzLP2rhw5lBoFBA==
+"@next/env@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/env/-/env-15.5.2.tgz#0c6b959313cd6e71afb69bf0deb417237f1d2f8a"
+  integrity sha512-Qe06ew4zt12LeO6N7j8/nULSOe3fMXE4dM6xgpBQNvdzyK1sv5y4oAP3bq4LamrvGCZtmRYnW8URFCeX5nFgGg==
 
 "@next/eslint-plugin-next@15.5.2":
   version "15.5.2"
@@ -727,45 +727,45 @@
   dependencies:
     fast-glob "3.3.1"
 
-"@next/swc-darwin-arm64@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/swc-darwin-arm64/-/swc-darwin-arm64-15.6.0-canary.7.tgz#628cd34ce9120000f1cb5b08963426431174fc57"
-  integrity sha512-POsBrxhrR3qvqXV+JZ6ZoBc8gJf8rhYe+OedceI1piPVqtJYOJa3EB4eaqcc+kMsllKRrH/goNlhLwtyhE+0Qg==
+"@next/swc-darwin-arm64@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/swc-darwin-arm64/-/swc-darwin-arm64-15.5.2.tgz#f69713326fc08f2eff3726fe19165cdb429d67c7"
+  integrity sha512-8bGt577BXGSd4iqFygmzIfTYizHb0LGWqH+qgIF/2EDxS5JsSdERJKA8WgwDyNBZgTIIA4D8qUtoQHmxIIquoQ==
 
-"@next/swc-darwin-x64@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/swc-darwin-x64/-/swc-darwin-x64-15.6.0-canary.7.tgz#37d4ebab14da74a2f8028daf6d76aab410153e06"
-  integrity sha512-lmk9ysBuSiPlAJZTCo/3O4mXNFosg6EDIf4GrmynIwCG2as6/KxzyD1WqFp56Exp8eFDjP7SFapD10sV43vCsA==
+"@next/swc-darwin-x64@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/swc-darwin-x64/-/swc-darwin-x64-15.5.2.tgz#560a9da4126bae75cbbd6899646ad7a2e4fdcc9b"
+  integrity sha512-2DjnmR6JHK4X+dgTXt5/sOCu/7yPtqpYt8s8hLkHFK3MGkka2snTv3yRMdHvuRtJVkPwCGsvBSwmoQCHatauFQ==
 
-"@next/swc-linux-arm64-gnu@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/swc-linux-arm64-gnu/-/swc-linux-arm64-gnu-15.6.0-canary.7.tgz#ce700cc0e0d24763136838223105a524b36694fa"
-  integrity sha512-why8k6d0SBm3AKoOD5S7ir3g+BF34l9oFKIoZrLaZaKBvNGpFcjc7Ovc2TunNMeaMJzv9k1dHYSap0EI5oSuzg==
+"@next/swc-linux-arm64-gnu@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/swc-linux-arm64-gnu/-/swc-linux-arm64-gnu-15.5.2.tgz#80b2be276e775e5a9286369ae54e536b0cdf8c3a"
+  integrity sha512-3j7SWDBS2Wov/L9q0mFJtEvQ5miIqfO4l7d2m9Mo06ddsgUK8gWfHGgbjdFlCp2Ek7MmMQZSxpGFqcC8zGh2AA==
 
-"@next/swc-linux-arm64-musl@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/swc-linux-arm64-musl/-/swc-linux-arm64-musl-15.6.0-canary.7.tgz#c791b8e15bf2c338b4cc0387fe7afb3ef83ecfcf"
-  integrity sha512-HzvTRsKvYj32Va4YuJN3n3xOxvk+6QwB63d/EsgmdkeA/vrqciUAmJDYpuzZEvRc3Yp2nyPq8KZxtHAr6ISZ2Q==
+"@next/swc-linux-arm64-musl@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/swc-linux-arm64-musl/-/swc-linux-arm64-musl-15.5.2.tgz#68cf676301755fd99aca11a7ebdb5eae88d7c2e4"
+  integrity sha512-s6N8k8dF9YGc5T01UPQ08yxsK6fUow5gG1/axWc1HVVBYQBgOjca4oUZF7s4p+kwhkB1bDSGR8QznWrFZ/Rt5g==
 
-"@next/swc-linux-x64-gnu@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/swc-linux-x64-gnu/-/swc-linux-x64-gnu-15.6.0-canary.7.tgz#c01c3a3d8e71660c49298dd053d078379b6b5919"
-  integrity sha512-6yRFrg2qWXOqa+1BI53J9EmHWFzKg9U2r+5R7n7BFUp8PH5SC92WBsmYTnh/RkvAYvdupiVzMervwwswCs6kFg==
+"@next/swc-linux-x64-gnu@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/swc-linux-x64-gnu/-/swc-linux-x64-gnu-15.5.2.tgz#209d9a79d0f2333544f863b0daca3f7e29f2eaff"
+  integrity sha512-o1RV/KOODQh6dM6ZRJGZbc+MOAHww33Vbs5JC9Mp1gDk8cpEO+cYC/l7rweiEalkSm5/1WGa4zY7xrNwObN4+Q==
 
-"@next/swc-linux-x64-musl@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/swc-linux-x64-musl/-/swc-linux-x64-musl-15.6.0-canary.7.tgz#3f4b39faef4a5f88b13e4c726b008ddc9717f819"
-  integrity sha512-O/JjvOvNK/Wao/OIQaA6evDkxkmFFQgJ1/hI1dVk6/PAeKmW2/Q+6Dodh97eAkOwedS1ZdQl2mojf87TzLvzdQ==
+"@next/swc-linux-x64-musl@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/swc-linux-x64-musl/-/swc-linux-x64-musl-15.5.2.tgz#d4ad1cfb5e99e51db669fe2145710c1abeadbd7f"
+  integrity sha512-/VUnh7w8RElYZ0IV83nUcP/J4KJ6LLYliiBIri3p3aW2giF+PAVgZb6mk8jbQSB3WlTai8gEmCAr7kptFa1H6g==
 
-"@next/swc-win32-arm64-msvc@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/swc-win32-arm64-msvc/-/swc-win32-arm64-msvc-15.6.0-canary.7.tgz#9bc5da0907b7ce67eedda02a6d56a09d9a539ccf"
-  integrity sha512-p9DvrDgnePofZCtiWVY7qZtwXxiOGJlAyy2LoGPYSGOUDhjbTG8j6XMUFXpV9UwpH+l7st522psO1BVzbpT8IQ==
+"@next/swc-win32-arm64-msvc@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/swc-win32-arm64-msvc/-/swc-win32-arm64-msvc-15.5.2.tgz#070e10e370a5447a198c2db100389646aca2c496"
+  integrity sha512-sMPyTvRcNKXseNQ/7qRfVRLa0VhR0esmQ29DD6pqvG71+JdVnESJaHPA8t7bc67KD5spP3+DOCNLhqlEI2ZgQg==
 
-"@next/swc-win32-x64-msvc@15.6.0-canary.7":
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/@next/swc-win32-x64-msvc/-/swc-win32-x64-msvc-15.6.0-canary.7.tgz#5b271c591ccbe67d5fa966dd22db86c547414fd1"
-  integrity sha512-f1ywT3xWu4StWKA1mZRyGfelu/h+W0OEEyBxQNXzXyYa0VGZb9LyCNb5cYoNKBm0Bw18Hp1PVe0bHuusemGCcw==
+"@next/swc-win32-x64-msvc@15.5.2":
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/@next/swc-win32-x64-msvc/-/swc-win32-x64-msvc-15.5.2.tgz#9237d40b82eaf2efc88baeba15b784d4126caf4a"
+  integrity sha512-W5VvyZHnxG/2ukhZF/9Ikdra5fdNftxI6ybeVKYvBPDtyx7x4jPPSNduUkfH5fo3zG0JQ0bPxgy41af2JX5D4Q==
 
 "@nodelib/fs.scandir@2.1.5":
   version "2.1.5"
@@ -866,13 +866,6 @@
   dependencies:
     csstype "^3.0.2"
 
-"@types/react@19.1.13":
-  version "19.1.13"
-  resolved "https://registry.yarnpkg.com/@types/react/-/react-19.1.13.tgz#fc650ffa680d739a25a530f5d7ebe00cdd771883"
-  integrity sha512-hHkbU/eoO3EG5/MZkuFSKmYqPbSVk5byPFa3e7y/8TybHiLMACgI8seVYlicwk7H5K/rI2px9xrQp/C+AUDTiQ==
-  dependencies:
-    csstype "^3.0.2"
-
 "@typescript-eslint/eslint-plugin@^5.4.2 || ^6.0.0 || ^7.0.0 || ^8.0.0":
   version "8.10.0"
   resolved "https://registry.yarnpkg.com/@typescript-eslint/eslint-plugin/-/eslint-plugin-8.10.0.tgz#9c8218ed62f9a322df10ded7c34990f014df44f2"
@@ -3104,11 +3097,6 @@ lru-cache@^10.2.0:
   resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-10.4.3.tgz#410fc8a17b70e598013df257c2446b7f3383f119"
   integrity sha512-JNAzZcXrCt42VGLuYz0zfAzDfAvJWW6AfYlDBQyDV5DClI2m5sAmK+OIO7s59XfsRsWHp02jAJrRadPRGTt6SQ==
 
-lru-cache@^11.2.2:
-  version "11.2.2"
-  resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-11.2.2.tgz#40fd37edffcfae4b2940379c0722dc6eeaa75f24"
-  integrity sha512-F9ODfyqML2coTIsQpSkRHnLSZMtkU8Q+mSfcaIyKwy58u+8k5nvAYeiNhsyMARvzNcXJ9QfWVrcPsC9e9rAxtg==
-
 lru-cache@^5.1.1:
   version "5.1.1"
   resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-5.1.1.tgz#1da27e6710271947695daf6848e847f01d84b920"
@@ -3211,25 +3199,25 @@ natural-compare@^1.4.0:
   resolved "https://registry.yarnpkg.com/natural-compare/-/natural-compare-1.4.0.tgz#4abebfeed7541f2c27acfb29bdbbd15c8d5ba4f7"
   integrity sha512-OWND8ei3VtNC9h7V60qff3SVobHr996CTwgxubgyQYEpg290h9J0buyECNNJexkFm5sOajh5G116RYA1c8ZMSw==
 
-next@15.6.0-canary.7:
-  version "15.6.0-canary.7"
-  resolved "https://registry.yarnpkg.com/next/-/next-15.6.0-canary.7.tgz#bfc2ac3c9a78e23d550c303d18247a263e6b5bc1"
-  integrity sha512-4ukX2mxat9wWT6E0Gw/3TOR9ULV1q399E42F86cwsPSFgTWa04ABhcTqO0r9J/QR1YWPR8WEgh9qUzmWA/1yEw==
+next@15.5.2:
+  version "15.5.2"
+  resolved "https://registry.yarnpkg.com/next/-/next-15.5.2.tgz#5e50102443fb0328a9dfcac2d82465c7bac93693"
+  integrity sha512-H8Otr7abj1glFhbGnvUt3gz++0AF1+QoCXEBmd/6aKbfdFwrn0LpA836Ed5+00va/7HQSDD+mOoVhn3tNy3e/Q==
   dependencies:
-    "@next/env" "15.6.0-canary.7"
+    "@next/env" "15.5.2"
     "@swc/helpers" "0.5.15"
     caniuse-lite "^1.0.30001579"
     postcss "8.4.31"
     styled-jsx "5.1.6"
   optionalDependencies:
-    "@next/swc-darwin-arm64" "15.6.0-canary.7"
-    "@next/swc-darwin-x64" "15.6.0-canary.7"
-    "@next/swc-linux-arm64-gnu" "15.6.0-canary.7"
-    "@next/swc-linux-arm64-musl" "15.6.0-canary.7"
-    "@next/swc-linux-x64-gnu" "15.6.0-canary.7"
-    "@next/swc-linux-x64-musl" "15.6.0-canary.7"
-    "@next/swc-win32-arm64-msvc" "15.6.0-canary.7"
-    "@next/swc-win32-x64-msvc" "15.6.0-canary.7"
+    "@next/swc-darwin-arm64" "15.5.2"
+    "@next/swc-darwin-x64" "15.5.2"
+    "@next/swc-linux-arm64-gnu" "15.5.2"
+    "@next/swc-linux-arm64-musl" "15.5.2"
+    "@next/swc-linux-x64-gnu" "15.5.2"
+    "@next/swc-linux-x64-musl" "15.5.2"
+    "@next/swc-win32-arm64-msvc" "15.5.2"
+    "@next/swc-win32-x64-msvc" "15.5.2"
     sharp "^0.34.3"
 
 node-releases@^2.0.18:

compiler/packages/babel-plugin-react-compiler/package.json

@@ -52,8 +52,8 @@
     "react-dom": "0.0.0-experimental-4beb1fd8-20241118",
     "ts-jest": "^29.1.1",
     "ts-node": "^10.9.2",
-    "zod": "^3.25.0 || ^4.0.0",
-    "zod-validation-error": "^3.5.0 || ^4.0.0"
+    "zod": "^3.22.4",
+    "zod-validation-error": "^2.1.0"
   },
   "resolutions": {
     "./**/@babel/parser": "7.7.4",

compiler/packages/babel-plugin-react-compiler/src/Babel/RunReactCompilerBabelPlugin.ts

@@ -17,7 +17,7 @@ export function runBabelPluginReactCompiler(
   text: string,
   file: string,
   language: 'flow' | 'typescript',
-  options: PluginOptions | null,
+  options: Partial<PluginOptions> | null,
   includeAst: boolean = false,
 ): BabelCore.BabelFileResult {
   const ast = BabelParser.parse(text, {

compiler/packages/babel-plugin-react-compiler/src/CompilerError.ts

@@ -536,8 +536,7 @@ function printErrorSummary(category: ErrorCategory, message: string): string {
     case ErrorCategory.StaticComponents:
     case ErrorCategory.Suppression:
     case ErrorCategory.Syntax:
-    case ErrorCategory.UseMemo:
-    case ErrorCategory.VoidUseMemo: {
+    case ErrorCategory.UseMemo: {
       heading = 'Error';
       break;
     }
@@ -583,10 +582,6 @@ export enum ErrorCategory {
    * Checking for valid usage of manual memoization
    */
   UseMemo = 'UseMemo',
-  /**
-   * Checking that useMemos always return a value
-   */
-  VoidUseMemo = 'VoidUseMemo',
   /**
    * Checking for higher order functions acting as factories for components/hooks
    */
@@ -674,21 +669,6 @@ export enum ErrorCategory {
   FBT = 'FBT',
 }
 
-export enum LintRulePreset {
-  /**
-   * Rules that are stable and included in the `recommended` preset.
-   */
-  Recommended = 'recommended',
-  /**
-   * Rules that are more experimental and only included in the `recommended-latest` preset.
-   */
-  RecommendedLatest = 'recommended-latest',
-  /**
-   * Rules that are disabled.
-   */
-  Off = 'off',
-}
-
 export type LintRule = {
   // Stores the category the rule corresponds to, used to filter errors when reporting
   category: ErrorCategory;
@@ -709,14 +689,15 @@ export type LintRule = {
   description: string;
 
   /**
-   * Configures the preset in which the rule is enabled. If 'off', the rule will not be included in
-   * any preset.
+   * If true, this rule will automatically appear in the default, "recommended" ESLint
+   * rule set. Otherwise it will be part of an `allRules` export that developers can
+   * use to opt-in to showing output of all possible rules.
    *
    * NOTE: not all validations are enabled by default! Setting this flag only affects
    * whether a given rule is part of the recommended set. The corresponding validation
    * also should be enabled by default if you want the error to actually show up!
    */
-  preset: LintRulePreset;
+  recommended: boolean;
 };
 
 const RULE_NAME_PATTERN = /^[a-z]+(-[a-z]+)*$/;
@@ -739,7 +720,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'automatic-effect-dependencies',
         description:
           'Verifies that automatic effect dependencies are compiled if opted-in',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.CapitalizedCalls: {
@@ -749,7 +730,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'capitalized-calls',
         description:
           'Validates against calling capitalized functions/methods instead of using JSX',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.Config: {
@@ -758,7 +739,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         severity: ErrorSeverity.Error,
         name: 'config',
         description: 'Validates the compiler configuration options',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.EffectDependencies: {
@@ -767,7 +748,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         severity: ErrorSeverity.Error,
         name: 'memoized-effect-dependencies',
         description: 'Validates that effect dependencies are memoized',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.EffectDerivationsOfState: {
@@ -777,7 +758,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'no-deriving-state-in-effects',
         description:
           'Validates against deriving values from state in an effect',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.EffectSetState: {
@@ -787,7 +768,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'set-state-in-effect',
         description:
           'Validates against calling setState synchronously in an effect, which can lead to re-renders that degrade performance',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.ErrorBoundaries: {
@@ -797,7 +778,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'error-boundaries',
         description:
           'Validates usage of error boundaries instead of try/catch for errors in child components',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.Factories: {
@@ -808,7 +789,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         description:
           'Validates against higher order functions defining nested components or hooks. ' +
           'Components and hooks should be defined at the module level',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.FBT: {
@@ -817,7 +798,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         severity: ErrorSeverity.Error,
         name: 'fbt',
         description: 'Validates usage of fbt',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.Fire: {
@@ -826,7 +807,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         severity: ErrorSeverity.Error,
         name: 'fire',
         description: 'Validates usage of `fire`',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.Gating: {
@@ -836,7 +817,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'gating',
         description:
           'Validates configuration of [gating mode](https://react.dev/reference/react-compiler/gating)',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.Globals: {
@@ -847,7 +828,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         description:
           'Validates against assignment/mutation of globals during render, part of ensuring that ' +
           '[side effects must render outside of render](https://react.dev/reference/rules/components-and-hooks-must-be-pure#side-effects-must-run-outside-of-render)',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.Hooks: {
@@ -861,7 +842,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
          * We need to dedeupe these (moving the remaining bits into the compiler) and then enable
          * this rule.
          */
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.Immutability: {
@@ -871,7 +852,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'immutability',
         description:
           'Validates against mutating props, state, and other values that [are immutable](https://react.dev/reference/rules/components-and-hooks-must-be-pure#props-and-state-are-immutable)',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.Invariant: {
@@ -880,7 +861,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         severity: ErrorSeverity.Error,
         name: 'invariant',
         description: 'Internal invariants',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.PreserveManualMemo: {
@@ -892,7 +873,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
           'Validates that existing manual memoized is preserved by the compiler. ' +
           'React Compiler will only compile components and hooks if its inference ' +
           '[matches or exceeds the existing manual memoization](https://react.dev/learn/react-compiler/introduction#what-should-i-do-about-usememo-usecallback-and-reactmemo)',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.Purity: {
@@ -902,7 +883,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'purity',
         description:
           'Validates that [components/hooks are pure](https://react.dev/reference/rules/components-and-hooks-must-be-pure) by checking that they do not call known-impure functions',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.Refs: {
@@ -912,7 +893,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'refs',
         description:
           'Validates correct usage of refs, not reading/writing during render. See the "pitfalls" section in [`useRef()` usage](https://react.dev/reference/react/useRef#usage)',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.RenderSetState: {
@@ -922,7 +903,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'set-state-in-render',
         description:
           'Validates against setting state during render, which can trigger additional renders and potential infinite render loops',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.StaticComponents: {
@@ -932,7 +913,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'static-components',
         description:
           'Validates that components are static, not recreated every render. Components that are recreated dynamically can reset state and trigger excessive re-rendering',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.Suppression: {
@@ -941,7 +922,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         severity: ErrorSeverity.Error,
         name: 'rule-suppression',
         description: 'Validates against suppression of other rules',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.Syntax: {
@@ -950,7 +931,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         severity: ErrorSeverity.Error,
         name: 'syntax',
         description: 'Validates against invalid syntax',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.Todo: {
@@ -959,7 +940,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         severity: ErrorSeverity.Hint,
         name: 'todo',
         description: 'Unimplemented features',
-        preset: LintRulePreset.Off,
+        recommended: false,
       };
     }
     case ErrorCategory.UnsupportedSyntax: {
@@ -969,7 +950,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'unsupported-syntax',
         description:
           'Validates against syntax that we do not plan to support in React Compiler',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     case ErrorCategory.UseMemo: {
@@ -979,17 +960,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'use-memo',
         description:
           'Validates usage of the useMemo() hook against common mistakes. See [`useMemo()` docs](https://react.dev/reference/react/useMemo) for more information.',
-        preset: LintRulePreset.Recommended,
-      };
-    }
-    case ErrorCategory.VoidUseMemo: {
-      return {
-        category,
-        severity: ErrorSeverity.Error,
-        name: 'void-use-memo',
-        description:
-          'Validates that useMemos always return a value and that the result of the useMemo is used by the component/hook. See [`useMemo()` docs](https://react.dev/reference/react/useMemo) for more information.',
-        preset: LintRulePreset.RecommendedLatest,
+        recommended: true,
       };
     }
     case ErrorCategory.IncompatibleLibrary: {
@@ -999,7 +970,7 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         name: 'incompatible-library',
         description:
           'Validates against usage of libraries which are incompatible with memoization (manual or automatic)',
-        preset: LintRulePreset.Recommended,
+        recommended: true,
       };
     }
     default: {

compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Imports.ts

@@ -18,7 +18,7 @@ import {
 import {getOrInsertWith} from '../Utils/utils';
 import {ExternalFunction, isHookName} from '../HIR/Environment';
 import {Err, Ok, Result} from '../Utils/Result';
-import {LoggerEvent, ParsedPluginOptions} from './Options';
+import {LoggerEvent, PluginOptions} from './Options';
 import {BabelFn, getReactCompilerRuntimeModule} from './Program';
 import {SuppressionRange} from './Suppression';
 
@@ -56,7 +56,7 @@ export function validateRestrictedImports(
 type ProgramContextOptions = {
   program: NodePath<t.Program>;
   suppressions: Array<SuppressionRange>;
-  opts: ParsedPluginOptions;
+  opts: PluginOptions;
   filename: string | null;
   code: string | null;
   hasModuleScopeOptOut: boolean;
@@ -66,7 +66,7 @@ export class ProgramContext {
    * Program and environment context
    */
   scope: BabelScope;
-  opts: ParsedPluginOptions;
+  opts: PluginOptions;
   filename: string | null;
   code: string | null;
   reactRuntimeModule: string;
@@ -240,7 +240,7 @@ export function addImportsToProgram(
   programContext: ProgramContext,
 ): void {
   const existingImports = getExistingImports(path);
-  const stmts: Array<t.ImportDeclaration | t.VariableDeclaration> = [];
+  const stmts: Array<t.ImportDeclaration> = [];
   const sortedModules = [...programContext.imports.entries()].sort(([a], [b]) =>
     a.localeCompare(b),
   );
@@ -303,29 +303,9 @@ export function addImportsToProgram(
     if (maybeExistingImports != null) {
       maybeExistingImports.pushContainer('specifiers', importSpecifiers);
     } else {
-      if (path.node.sourceType === 'module') {
-        stmts.push(
-          t.importDeclaration(importSpecifiers, t.stringLiteral(moduleName)),
-        );
-      } else {
-        stmts.push(
-          t.variableDeclaration('const', [
-            t.variableDeclarator(
-              t.objectPattern(
-                sortedImport.map(specifier => {
-                  return t.objectProperty(
-                    t.identifier(specifier.imported),
-                    t.identifier(specifier.name),
-                  );
-                }),
-              ),
-              t.callExpression(t.identifier('require'), [
-                t.stringLiteral(moduleName),
-              ]),
-            ),
-          ]),
-        );
-      }
+      stmts.push(
+        t.importDeclaration(importSpecifiers, t.stringLiteral(moduleName)),
+      );
     }
   }
   path.unshiftContainer('body', stmts);

compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Options.ts

@@ -6,7 +6,7 @@
  */
 
 import * as t from '@babel/types';
-import {z} from 'zod/v4';
+import {z} from 'zod';
 import {
   CompilerDiagnostic,
   CompilerError,
@@ -20,7 +20,7 @@ import {
   tryParseExternalFunction,
 } from '../HIR/Environment';
 import {hasOwnProperty} from '../Utils/utils';
-import {fromZodError} from 'zod-validation-error/v4';
+import {fromZodError} from 'zod-validation-error';
 import {CompilerPipelineValue} from './Pipeline';
 
 const PanicThresholdOptionsSchema = z.enum([
@@ -51,8 +51,8 @@ const CustomOptOutDirectiveSchema = z
   .default(null);
 type CustomOptOutDirective = z.infer<typeof CustomOptOutDirectiveSchema>;
 
-export type PluginOptions = Partial<{
-  environment: Partial<EnvironmentConfig>;
+export type PluginOptions = {
+  environment: EnvironmentConfig;
 
   logger: Logger | null;
 
@@ -166,11 +166,7 @@ export type PluginOptions = Partial<{
    * a userspace approximation of runtime APIs.
    */
   target: CompilerReactTarget;
-}>;
-
-export type ParsedPluginOptions = Required<
-  Omit<PluginOptions, 'environment'>
-> & {environment: EnvironmentConfig};
+};
 
 const CompilerReactTargetSchema = z.union([
   z.literal('17'),
@@ -286,7 +282,7 @@ export type Logger = {
   debugLogIRs?: (value: CompilerPipelineValue) => void;
 };
 
-export const defaultOptions: ParsedPluginOptions = {
+export const defaultOptions: PluginOptions = {
   compilationMode: 'infer',
   panicThreshold: 'none',
   environment: parseEnvironmentConfig({}).unwrap(),
@@ -303,9 +299,9 @@ export const defaultOptions: ParsedPluginOptions = {
   enableReanimatedCheck: true,
   customOptOutDirectives: null,
   target: '19',
-};
+} as const;
 
-export function parsePluginOptions(obj: unknown): ParsedPluginOptions {
+export function parsePluginOptions(obj: unknown): PluginOptions {
   if (obj == null || typeof obj !== 'object') {
     return defaultOptions;
   }

compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Pipeline.ts

@@ -276,7 +276,7 @@ function runWithEnvironment(
     }
 
     if (env.config.validateNoSetStateInEffects) {
-      env.logErrors(validateNoSetStateInEffects(hir, env));
+      env.logErrors(validateNoSetStateInEffects(hir));
     }
 
     if (env.config.validateNoJSXInTryStatements) {

compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Program.ts

@@ -23,11 +23,7 @@ import {
   ProgramContext,
   validateRestrictedImports,
 } from './Imports';
-import {
-  CompilerReactTarget,
-  ParsedPluginOptions,
-  PluginOptions,
-} from './Options';
+import {CompilerReactTarget, PluginOptions} from './Options';
 import {compileFn} from './Pipeline';
 import {
   filterSuppressionsThatAffectFunction,
@@ -38,7 +34,7 @@ import {GeneratedSource} from '../HIR';
 import {Err, Ok, Result} from '../Utils/Result';
 
 export type CompilerPass = {
-  opts: ParsedPluginOptions;
+  opts: PluginOptions;
   filename: string | null;
   comments: Array<t.CommentBlock | t.CommentLine>;
   code: string | null;
@@ -49,7 +45,7 @@ const DYNAMIC_GATING_DIRECTIVE = new RegExp('^use memo if\\(([^\\)]*)\\)$');
 
 export function tryFindDirectiveEnablingMemoization(
   directives: Array<t.Directive>,
-  opts: ParsedPluginOptions,
+  opts: PluginOptions,
 ): Result<t.Directive | null, CompilerError> {
   const optIn = directives.find(directive =>
     OPT_IN_DIRECTIVES.has(directive.value.value),
@@ -85,7 +81,7 @@ export function findDirectiveDisablingMemoization(
 }
 function findDirectivesDynamicGating(
   directives: Array<t.Directive>,
-  opts: ParsedPluginOptions,
+  opts: PluginOptions,
 ): Result<
   {
     gating: ExternalFunction;

compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Reanimated.ts

@@ -7,7 +7,7 @@
 
 import type * as BabelCore from '@babel/core';
 import {hasOwnProperty} from '../Utils/utils';
-import {ParsedPluginOptions} from './Options';
+import {PluginOptions} from './Options';
 
 function hasModule(name: string): boolean {
   if (typeof require === 'undefined') {
@@ -52,9 +52,7 @@ export function pipelineUsesReanimatedPlugin(
   return hasModule('react-native-reanimated');
 }
 
-export function injectReanimatedFlag(
-  options: ParsedPluginOptions,
-): ParsedPluginOptions {
+export function injectReanimatedFlag(options: PluginOptions): PluginOptions {
   return {
     ...options,
     environment: {

compiler/packages/babel-plugin-react-compiler/src/HIR/BuildHIR.ts

@@ -3081,12 +3081,6 @@ function isReorderableExpression(
         return true;
       }
     }
-    case 'TSInstantiationExpression': {
-      const innerExpr = (expr as NodePath<t.TSInstantiationExpression>).get(
-        'expression',
-      ) as NodePath<t.Expression>;
-      return isReorderableExpression(builder, innerExpr, allowLocalIdentifiers);
-    }
     case 'RegExpLiteral':
     case 'StringLiteral':
     case 'NumericLiteral':

compiler/packages/babel-plugin-react-compiler/src/HIR/CollectHoistablePropertyLoads.ts

@@ -454,32 +454,6 @@ function collectNonNullsInBlocks(
             assumedNonNullObjects.add(entry);
           }
         }
-      } else if (
-        fn.env.config.enablePreserveExistingMemoizationGuarantees &&
-        instr.value.kind === 'StartMemoize' &&
-        instr.value.deps != null
-      ) {
-        for (const dep of instr.value.deps) {
-          if (dep.root.kind === 'NamedLocal') {
-            if (
-              !isImmutableAtInstr(dep.root.value.identifier, instr.id, context)
-            ) {
-              continue;
-            }
-            for (let i = 0; i < dep.path.length; i++) {
-              const pathEntry = dep.path[i]!;
-              if (pathEntry.optional) {
-                break;
-              }
-              const depNode = context.registry.getOrCreateProperty({
-                identifier: dep.root.value.identifier,
-                path: dep.path.slice(0, i),
-                reactive: dep.root.value.reactive,
-              });
-              assumedNonNullObjects.add(depNode);
-            }
-          }
-        }
       }
     }
 

compiler/packages/babel-plugin-react-compiler/src/HIR/DefaultModuleTypeProvider.ts

@@ -86,24 +86,6 @@ export function defaultModuleTypeProvider(
         },
       };
     }
-    case '@tanstack/react-virtual': {
-      return {
-        kind: 'object',
-        properties: {
-          /*
-           * Many of the properties of `useVirtualizer()`'s return value are incompatible, so we mark the entire hook
-           * as incompatible
-           */
-          useVirtualizer: {
-            kind: 'hook',
-            positionalParams: [],
-            restParam: Effect.Read,
-            returnType: {kind: 'type', name: 'Any'},
-            knownIncompatible: `TanStack Virtual's \`useVirtualizer()\` API returns functions that cannot be memoized safely`,
-          },
-        },
-      };
-    }
   }
   return null;
 }

compiler/packages/babel-plugin-react-compiler/src/HIR/Environment.ts

@@ -6,8 +6,8 @@
  */
 
 import * as t from '@babel/types';
-import {ZodError, z} from 'zod/v4';
-import {fromZodError} from 'zod-validation-error/v4';
+import {ZodError, z} from 'zod';
+import {fromZodError} from 'zod-validation-error';
 import {CompilerError} from '../CompilerError';
 import {Logger, ProgramContext} from '../Entrypoint';
 import {Err, Ok, Result} from '../Utils/Result';
@@ -159,7 +159,7 @@ export const EnvironmentConfigSchema = z.object({
    * A function that, given the name of a module, can optionally return a description
    * of that module's type signature.
    */
-  moduleTypeProvider: z.nullable(z.any()).default(null),
+  moduleTypeProvider: z.nullable(z.function().args(z.string())).default(null),
 
   /**
    * A list of functions which the application compiles as macros, where
@@ -210,7 +210,7 @@ export const EnvironmentConfigSchema = z.object({
    * that if a useEffect or useCallback references a function value, that function value will be
    * considered frozen, and in turn all of its referenced variables will be considered frozen as well.
    */
-  enablePreserveExistingMemoizationGuarantees: z.boolean().default(true),
+  enablePreserveExistingMemoizationGuarantees: z.boolean().default(false),
 
   /**
    * Validates that all useMemo/useCallback values are also memoized by Forget. This mode can be
@@ -249,7 +249,7 @@ export const EnvironmentConfigSchema = z.object({
    * Allows specifying a function that can populate HIR with type information from
    * Flow
    */
-  flowTypeProvider: z.nullable(z.any()).default(null),
+  flowTypeProvider: z.nullable(z.function().args(z.string())).default(null),
 
   /**
    * Enables inference of optional dependency chains. Without this flag
@@ -621,13 +621,6 @@ export const EnvironmentConfigSchema = z.object({
    */
   enableTreatRefLikeIdentifiersAsRefs: z.boolean().default(true),
 
-  /**
-   * Treat identifiers as SetState type if both
-   * - they are named with a "set-" prefix
-   * - they are called somewhere
-   */
-  enableTreatSetIdentifiersAsStateSetters: z.boolean().default(false),
-
   /*
    * If specified a value, the compiler lowers any calls to `useContext` to use
    * this value as the callee.
@@ -659,7 +652,7 @@ export const EnvironmentConfigSchema = z.object({
    * Invalid:
    *   useMemo(() => { ... }, [...]);
    */
-  validateNoVoidUseMemo: z.boolean().default(true),
+  validateNoVoidUseMemo: z.boolean().default(false),
 
   /**
    * Validates that Components/Hooks are always defined at module level. This prevents scope
@@ -667,13 +660,6 @@ export const EnvironmentConfigSchema = z.object({
    * while its parent function remains uncompiled.
    */
   validateNoDynamicallyCreatedComponentsOrHooks: z.boolean().default(false),
-
-  /**
-   * When enabled, allows setState calls in effects when the value being set is
-   * derived from a ref. This is useful for patterns where initial layout measurements
-   * from refs need to be stored in state during mount.
-   */
-  enableAllowSetStateFromRefsInEffects: z.boolean().default(true),
 });
 
 export type EnvironmentConfig = z.infer<typeof EnvironmentConfigSchema>;
@@ -906,12 +892,6 @@ export class Environment {
       if (moduleTypeProvider == null) {
         return null;
       }
-      if (typeof moduleTypeProvider !== 'function') {
-        CompilerError.throwInvalidConfig({
-          reason: `Expected a function for \`moduleTypeProvider\``,
-          loc,
-        });
-      }
       const unparsedModuleConfig = moduleTypeProvider(moduleName);
       if (unparsedModuleConfig != null) {
         const parsedModuleConfig = TypeSchema.safeParse(unparsedModuleConfig);

compiler/packages/babel-plugin-react-compiler/src/HIR/HIR.ts

@@ -16,7 +16,7 @@ import {assertExhaustive} from '../Utils/utils';
 import {Environment, ReactFunctionType} from './Environment';
 import type {HookKind} from './ObjectShape';
 import {Type, makeType} from './Types';
-import {z} from 'zod/v4';
+import {z} from 'zod';
 import type {AliasingEffect} from '../Inference/AliasingEffects';
 import {isReservedWord} from '../Utils/Keyword';
 import {Err, Ok, Result} from '../Utils/Result';

compiler/packages/babel-plugin-react-compiler/src/HIR/HIRBuilder.ts

@@ -988,7 +988,7 @@ export function createTemporaryPlace(
     identifier: makeTemporaryIdentifier(env.nextIdentifierId, loc),
     reactive: false,
     effect: Effect.Unknown,
-    loc,
+    loc: GeneratedSource,
   };
 }
 

compiler/packages/babel-plugin-react-compiler/src/HIR/TypeSchema.ts

@@ -6,7 +6,7 @@
  */
 
 import {isValidIdentifier} from '@babel/types';
-import {z} from 'zod/v4';
+import {z} from 'zod';
 import {Effect, ValueKind} from '..';
 import {
   EffectSchema,

compiler/packages/babel-plugin-react-compiler/src/Inference/DropManualMemoization.ts

@@ -11,6 +11,7 @@ import {
   CallExpression,
   Effect,
   Environment,
+  FinishMemoize,
   FunctionExpression,
   HIRFunction,
   IdentifierId,
@@ -24,6 +25,7 @@ import {
   Place,
   PropertyLoad,
   SpreadPattern,
+  StartMemoize,
   TInstruction,
   getHookKindForType,
   makeInstructionId,
@@ -182,52 +184,36 @@ function makeManualMemoizationMarkers(
   depsList: Array<ManualMemoDependency> | null,
   memoDecl: Place,
   manualMemoId: number,
-): [Array<Instruction>, Array<Instruction>] {
-  const temp = createTemporaryPlace(env, memoDecl.loc);
+): [TInstruction<StartMemoize>, TInstruction<FinishMemoize>] {
   return [
-    [
-      {
-        id: makeInstructionId(0),
-        lvalue: createTemporaryPlace(env, fnExpr.loc),
-        value: {
-          kind: 'StartMemoize',
-          manualMemoId,
-          /*
-           * Use deps list from source instead of inferred deps
-           * as dependencies
-           */
-          deps: depsList,
-          loc: fnExpr.loc,
-        },
-        effects: null,
+    {
+      id: makeInstructionId(0),
+      lvalue: createTemporaryPlace(env, fnExpr.loc),
+      value: {
+        kind: 'StartMemoize',
+        manualMemoId,
+        /*
+         * Use deps list from source instead of inferred deps
+         * as dependencies
+         */
+        deps: depsList,
         loc: fnExpr.loc,
       },
-    ],
-    [
-      {
-        id: makeInstructionId(0),
-        lvalue: {...temp},
-        value: {
-          kind: 'LoadLocal',
-          place: {...memoDecl},
-          loc: memoDecl.loc,
-        },
-        effects: null,
-        loc: memoDecl.loc,
+      effects: null,
+      loc: fnExpr.loc,
+    },
+    {
+      id: makeInstructionId(0),
+      lvalue: createTemporaryPlace(env, fnExpr.loc),
+      value: {
+        kind: 'FinishMemoize',
+        manualMemoId,
+        decl: {...memoDecl},
+        loc: fnExpr.loc,
       },
-      {
-        id: makeInstructionId(0),
-        lvalue: createTemporaryPlace(env, memoDecl.loc),
-        value: {
-          kind: 'FinishMemoize',
-          manualMemoId,
-          decl: {...temp},
-          loc: memoDecl.loc,
-        },
-        effects: null,
-        loc: memoDecl.loc,
-      },
-    ],
+      effects: null,
+      loc: fnExpr.loc,
+    },
   ];
 }
 
@@ -423,7 +409,10 @@ export function dropManualMemoization(
    *   LoadLocal fnArg
    * - (if validation is enabled) collect manual memoization markers
    */
-  const queuedInserts: Map<InstructionId, Array<Instruction>> = new Map();
+  const queuedInserts: Map<
+    InstructionId,
+    TInstruction<StartMemoize> | TInstruction<FinishMemoize>
+  > = new Map();
   for (const [_, block] of func.body.blocks) {
     for (let i = 0; i < block.instructions.length; i++) {
       const instr = block.instructions[i]!;
@@ -449,6 +438,40 @@ export function dropManualMemoization(
             continue;
           }
 
+          /**
+           * Bailout on void return useMemos. This is an anti-pattern where code might be using
+           * useMemo like useEffect: running arbirtary side-effects synced to changes in specific
+           * values.
+           */
+          if (
+            func.env.config.validateNoVoidUseMemo &&
+            manualMemo.kind === 'useMemo'
+          ) {
+            const funcToCheck = sidemap.functions.get(
+              fnPlace.identifier.id,
+            )?.value;
+            if (funcToCheck !== undefined && funcToCheck.loweredFunc.func) {
+              if (!hasNonVoidReturn(funcToCheck.loweredFunc.func)) {
+                errors.pushDiagnostic(
+                  CompilerDiagnostic.create({
+                    category: ErrorCategory.UseMemo,
+                    reason: 'useMemo() callbacks must return a value',
+                    description: `This ${
+                      manualMemo.loadInstr.value.kind === 'PropertyLoad'
+                        ? 'React.useMemo'
+                        : 'useMemo'
+                    } callback doesn't return a value. useMemo is for computing and caching values, not for arbitrary side effects`,
+                    suggestions: null,
+                  }).withDetails({
+                    kind: 'error',
+                    loc: instr.value.loc,
+                    message: 'useMemo() callbacks must return a value',
+                  }),
+                );
+              }
+            }
+          }
+
           instr.value = getManualMemoizationReplacement(
             fnPlace,
             instr.value.loc,
@@ -534,11 +557,11 @@ export function dropManualMemoization(
       let nextInstructions: Array<Instruction> | null = null;
       for (let i = 0; i < block.instructions.length; i++) {
         const instr = block.instructions[i];
-        const insertInstructions = queuedInserts.get(instr.id);
-        if (insertInstructions != null) {
+        const insertInstr = queuedInserts.get(instr.id);
+        if (insertInstr != null) {
           nextInstructions = nextInstructions ?? block.instructions.slice(0, i);
           nextInstructions.push(instr);
-          nextInstructions.push(...insertInstructions);
+          nextInstructions.push(insertInstr);
         } else if (nextInstructions != null) {
           nextInstructions.push(instr);
         }
@@ -606,3 +629,17 @@ function findOptionalPlaces(fn: HIRFunction): Set<IdentifierId> {
   }
   return optionals;
 }
+
+function hasNonVoidReturn(func: HIRFunction): boolean {
+  for (const [, block] of func.body.blocks) {
+    if (block.terminal.kind === 'return') {
+      if (
+        block.terminal.returnVariant === 'Explicit' ||
+        block.terminal.returnVariant === 'Implicit'
+      ) {
+        return true;
+      }
+    }
+  }
+  return false;
+}

compiler/packages/babel-plugin-react-compiler/src/Inference/InferMutationAliasingEffects.ts

@@ -748,14 +748,10 @@ function applyEffect(
     case 'Alias':
     case 'Capture': {
       CompilerError.invariant(
-        effect.kind === 'Capture' ||
-          effect.kind === 'MaybeAlias' ||
-          initialized.has(effect.into.identifier.id),
+        effect.kind === 'Capture' || initialized.has(effect.into.identifier.id),
         {
-          reason: `Expected destination to already be initialized within this instruction`,
-          description:
-            `Destination ${printPlace(effect.into)} is not initialized in this ` +
-            `instruction for effect ${printAliasingEffect(effect)}`,
+          reason: `Expected destination value to already be initialized within this instruction for Alias effect`,
+          description: `Destination ${printPlace(effect.into)} is not initialized in this instruction`,
           details: [
             {
               kind: 'error',
@@ -771,67 +767,49 @@ function applyEffect(
        * copy-on-write semantics, then we can prune the effect
        */
       const intoKind = state.kind(effect.into).kind;
-      let destinationType: 'context' | 'mutable' | null = null;
+      let isMutableDesination: boolean;
       switch (intoKind) {
-        case ValueKind.Context: {
-          destinationType = 'context';
-          break;
-        }
+        case ValueKind.Context:
         case ValueKind.Mutable:
         case ValueKind.MaybeFrozen: {
-          destinationType = 'mutable';
+          isMutableDesination = true;
+          break;
+        }
+        default: {
+          isMutableDesination = false;
           break;
         }
       }
       const fromKind = state.kind(effect.from).kind;
-      let sourceType: 'context' | 'mutable' | 'frozen' | null = null;
+      let isMutableReferenceType: boolean;
       switch (fromKind) {
-        case ValueKind.Context: {
-          sourceType = 'context';
-          break;
-        }
         case ValueKind.Global:
         case ValueKind.Primitive: {
+          isMutableReferenceType = false;
           break;
         }
         case ValueKind.Frozen: {
-          sourceType = 'frozen';
+          isMutableReferenceType = false;
+          applyEffect(
+            context,
+            state,
+            {
+              kind: 'ImmutableCapture',
+              from: effect.from,
+              into: effect.into,
+            },
+            initialized,
+            effects,
+          );
           break;
         }
         default: {
-          sourceType = 'mutable';
+          isMutableReferenceType = true;
           break;
         }
       }
-
-      if (sourceType === 'frozen') {
-        applyEffect(
-          context,
-          state,
-          {
-            kind: 'ImmutableCapture',
-            from: effect.from,
-            into: effect.into,
-          },
-          initialized,
-          effects,
-        );
-      } else if (
-        (sourceType === 'mutable' && destinationType === 'mutable') ||
-        effect.kind === 'MaybeAlias'
-      ) {
+      if (isMutableDesination && isMutableReferenceType) {
         effects.push(effect);
-      } else if (
-        (sourceType === 'context' && destinationType != null) ||
-        (sourceType === 'mutable' && destinationType === 'context')
-      ) {
-        applyEffect(
-          context,
-          state,
-          {kind: 'MaybeAlias', from: effect.from, into: effect.into},
-          initialized,
-          effects,
-        );
       }
       break;
     }
@@ -1816,16 +1794,8 @@ function computeSignatureForInstruction(
     }
     case 'PropertyStore':
     case 'ComputedStore': {
-      /**
-       * Add a hint about naming as "ref"/"-Ref", but only if we weren't able to infer any
-       * type for the object. In some cases the variable may be named like a ref, but is
-       * also used as a ref callback such that we infer the type as a function rather than
-       * a ref.
-       */
       const mutationReason: MutationReason | null =
-        value.kind === 'PropertyStore' &&
-        value.property === 'current' &&
-        value.object.identifier.type.kind === 'Type'
+        value.kind === 'PropertyStore' && value.property === 'current'
           ? {kind: 'AssignCurrentProperty'}
           : null;
       effects.push({

compiler/packages/babel-plugin-react-compiler/src/Inference/InferMutationAliasingRanges.ts

@@ -779,13 +779,7 @@ class AliasingState {
         if (edge.index >= index) {
           break;
         }
-        queue.push({
-          place: edge.node,
-          transitive,
-          direction: 'forwards',
-          // Traversing a maybeAlias edge always downgrades to conditional mutation
-          kind: edge.kind === 'maybeAlias' ? MutationKind.Conditional : kind,
-        });
+        queue.push({place: edge.node, transitive, direction: 'forwards', kind});
       }
       for (const [alias, when] of node.createdFrom) {
         if (when >= index) {
@@ -813,12 +807,7 @@ class AliasingState {
           if (when >= index) {
             continue;
           }
-          queue.push({
-            place: alias,
-            transitive,
-            direction: 'backwards',
-            kind,
-          });
+          queue.push({place: alias, transitive, direction: 'backwards', kind});
         }
         /**
          * MaybeAlias indicates potential data flow from unknown function calls,

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/MemoizeFbtAndMacroOperandsInSameScope.ts

@@ -7,17 +7,14 @@
 
 import {
   HIRFunction,
-  Identifier,
   IdentifierId,
-  InstructionValue,
   makeInstructionId,
   MutableRange,
   Place,
-  ReactiveScope,
+  ReactiveValue,
 } from '../HIR';
 import {Macro, MacroMethod} from '../HIR/Environment';
-import {eachInstructionValueOperand} from '../HIR/visitors';
-import {Iterable_some} from '../Utils/utils';
+import {eachReactiveValueOperand} from './visitors';
 
 /**
  * This pass supports the `fbt` translation system (https://facebook.github.io/fbt/)
@@ -51,49 +48,24 @@ export function memoizeFbtAndMacroOperandsInSameScope(
     ...Array.from(FBT_TAGS).map((tag): Macro => [tag, []]),
     ...(fn.env.config.customMacros ?? []),
   ]);
-  /**
-   * Set of all identifiers that load fbt or other macro functions or their nested
-   * properties, as well as values known to be the results of invoking macros
-   */
-  const macroTagsCalls: Set<IdentifierId> = new Set();
-  /**
-   * Mapping of lvalue => list of operands for all expressions where either
-   * the lvalue is a known fbt/macro call and/or the operands transitively
-   * contain fbt/macro calls.
-   *
-   * This is the key data structure that powers the scope merging: we start
-   * at the lvalues and merge operands into the lvalue's scope.
-   */
-  const macroValues: Map<Identifier, Array<Identifier>> = new Map();
-  // Tracks methods loaded from macros, like fbt.param or idx.foo
+  const fbtValues: Set<IdentifierId> = new Set();
   const macroMethods = new Map<IdentifierId, Array<Array<MacroMethod>>>();
-
-  visit(fn, fbtMacroTags, macroTagsCalls, macroMethods, macroValues);
-
-  for (const root of macroValues.keys()) {
-    const scope = root.scope;
-    if (scope == null) {
-      continue;
+  while (true) {
+    let vsize = fbtValues.size;
+    let msize = macroMethods.size;
+    visit(fn, fbtMacroTags, fbtValues, macroMethods);
+    if (vsize === fbtValues.size && msize === macroMethods.size) {
+      break;
     }
-    // Merge the operands into the same scope if this is a known macro invocation
-    if (!macroTagsCalls.has(root.id)) {
-      continue;
-    }
-    mergeScopes(root, scope, macroValues, macroTagsCalls);
   }
-
-  return macroTagsCalls;
+  return fbtValues;
 }
 
 export const FBT_TAGS: Set<string> = new Set([
   'fbt',
   'fbt:param',
-  'fbt:enum',
-  'fbt:plural',
   'fbs',
   'fbs:param',
-  'fbs:enum',
-  'fbs:plural',
 ]);
 export const SINGLE_CHILD_FBT_TAGS: Set<string> = new Set([
   'fbt:param',
@@ -103,22 +75,10 @@ export const SINGLE_CHILD_FBT_TAGS: Set<string> = new Set([
 function visit(
   fn: HIRFunction,
   fbtMacroTags: Set<Macro>,
-  macroTagsCalls: Set<IdentifierId>,
+  fbtValues: Set<IdentifierId>,
   macroMethods: Map<IdentifierId, Array<Array<MacroMethod>>>,
-  macroValues: Map<Identifier, Array<Identifier>>,
 ): void {
   for (const [, block] of fn.body.blocks) {
-    for (const phi of block.phis) {
-      const macroOperands: Array<Identifier> = [];
-      for (const operand of phi.operands.values()) {
-        if (macroValues.has(operand.identifier)) {
-          macroOperands.push(operand.identifier);
-        }
-      }
-      if (macroOperands.length !== 0) {
-        macroValues.set(phi.place.identifier, macroOperands);
-      }
-    }
     for (const instruction of block.instructions) {
       const {lvalue, value} = instruction;
       if (lvalue === null) {
@@ -133,13 +93,13 @@ function visit(
          * We don't distinguish between tag names and strings, so record
          * all `fbt` string literals in case they are used as a jsx tag.
          */
-        macroTagsCalls.add(lvalue.identifier.id);
+        fbtValues.add(lvalue.identifier.id);
       } else if (
         value.kind === 'LoadGlobal' &&
         matchesExactTag(value.binding.name, fbtMacroTags)
       ) {
         // Record references to `fbt` as a global
-        macroTagsCalls.add(lvalue.identifier.id);
+        fbtValues.add(lvalue.identifier.id);
       } else if (
         value.kind === 'LoadGlobal' &&
         matchTagRoot(value.binding.name, fbtMacroTags) !== null
@@ -161,66 +121,84 @@ function visit(
             if (method.length > 1) {
               newMethods.push(method.slice(1));
             } else {
-              macroTagsCalls.add(lvalue.identifier.id);
+              fbtValues.add(lvalue.identifier.id);
             }
           }
         }
         if (newMethods.length > 0) {
           macroMethods.set(lvalue.identifier.id, newMethods);
         }
-      } else if (
-        value.kind === 'PropertyLoad' &&
-        macroTagsCalls.has(value.object.identifier.id)
-      ) {
-        macroTagsCalls.add(lvalue.identifier.id);
-      } else if (
-        isFbtJsxExpression(fbtMacroTags, macroTagsCalls, value) ||
-        isFbtJsxChild(macroTagsCalls, lvalue, value) ||
-        isFbtCallExpression(macroTagsCalls, value)
-      ) {
-        macroTagsCalls.add(lvalue.identifier.id);
-        macroValues.set(
-          lvalue.identifier,
-          Array.from(
-            eachInstructionValueOperand(value),
-            operand => operand.identifier,
-          ),
-        );
-      } else if (
-        Iterable_some(eachInstructionValueOperand(value), operand =>
-          macroValues.has(operand.identifier),
-        )
-      ) {
-        const macroOperands: Array<Identifier> = [];
-        for (const operand of eachInstructionValueOperand(value)) {
-          if (macroValues.has(operand.identifier)) {
-            macroOperands.push(operand.identifier);
-          }
+      } else if (isFbtCallExpression(fbtValues, value)) {
+        const fbtScope = lvalue.identifier.scope;
+        if (fbtScope === null) {
+          continue;
+        }
+
+        /*
+         * if the JSX element's tag was `fbt`, mark all its operands
+         * to ensure that they end up in the same scope as the jsx element
+         * itself.
+         */
+        for (const operand of eachReactiveValueOperand(value)) {
+          operand.identifier.scope = fbtScope;
+
+          // Expand the jsx element's range to account for its operands
+          expandFbtScopeRange(fbtScope.range, operand.identifier.mutableRange);
+          fbtValues.add(operand.identifier.id);
+        }
+      } else if (
+        isFbtJsxExpression(fbtMacroTags, fbtValues, value) ||
+        isFbtJsxChild(fbtValues, lvalue, value)
+      ) {
+        const fbtScope = lvalue.identifier.scope;
+        if (fbtScope === null) {
+          continue;
+        }
+
+        /*
+         * if the JSX element's tag was `fbt`, mark all its operands
+         * to ensure that they end up in the same scope as the jsx element
+         * itself.
+         */
+        for (const operand of eachReactiveValueOperand(value)) {
+          operand.identifier.scope = fbtScope;
+
+          // Expand the jsx element's range to account for its operands
+          expandFbtScopeRange(fbtScope.range, operand.identifier.mutableRange);
+
+          /*
+           * NOTE: we add the operands as fbt values so that they are also
+           * grouped with this expression
+           */
+          fbtValues.add(operand.identifier.id);
+        }
+      } else if (fbtValues.has(lvalue.identifier.id)) {
+        const fbtScope = lvalue.identifier.scope;
+        if (fbtScope === null) {
+          return;
+        }
+
+        for (const operand of eachReactiveValueOperand(value)) {
+          if (
+            operand.identifier.name !== null &&
+            operand.identifier.name.kind === 'named'
+          ) {
+            /*
+             * named identifiers were already locals, we only have to force temporaries
+             * into the same scope
+             */
+            continue;
+          }
+          operand.identifier.scope = fbtScope;
+
+          // Expand the jsx element's range to account for its operands
+          expandFbtScopeRange(fbtScope.range, operand.identifier.mutableRange);
         }
-        macroValues.set(lvalue.identifier, macroOperands);
       }
     }
   }
 }
 
-function mergeScopes(
-  root: Identifier,
-  scope: ReactiveScope,
-  macroValues: Map<Identifier, Array<Identifier>>,
-  macroTagsCalls: Set<IdentifierId>,
-): void {
-  const operands = macroValues.get(root);
-  if (operands == null) {
-    return;
-  }
-  for (const operand of operands) {
-    operand.scope = scope;
-    expandFbtScopeRange(scope.range, operand.mutableRange);
-    macroTagsCalls.add(operand.id);
-    mergeScopes(operand, scope, macroValues, macroTagsCalls);
-  }
-}
-
 function matchesExactTag(s: string, tags: Set<Macro>): boolean {
   return Array.from(tags).some(macro =>
     typeof macro === 'string'
@@ -251,40 +229,39 @@ function matchTagRoot(
 }
 
 function isFbtCallExpression(
-  macroTagsCalls: Set<IdentifierId>,
-  value: InstructionValue,
+  fbtValues: Set<IdentifierId>,
+  value: ReactiveValue,
 ): boolean {
   return (
     (value.kind === 'CallExpression' &&
-      macroTagsCalls.has(value.callee.identifier.id)) ||
-    (value.kind === 'MethodCall' &&
-      macroTagsCalls.has(value.property.identifier.id))
+      fbtValues.has(value.callee.identifier.id)) ||
+    (value.kind === 'MethodCall' && fbtValues.has(value.property.identifier.id))
   );
 }
 
 function isFbtJsxExpression(
   fbtMacroTags: Set<Macro>,
-  macroTagsCalls: Set<IdentifierId>,
-  value: InstructionValue,
+  fbtValues: Set<IdentifierId>,
+  value: ReactiveValue,
 ): boolean {
   return (
     value.kind === 'JsxExpression' &&
     ((value.tag.kind === 'Identifier' &&
-      macroTagsCalls.has(value.tag.identifier.id)) ||
+      fbtValues.has(value.tag.identifier.id)) ||
       (value.tag.kind === 'BuiltinTag' &&
         matchesExactTag(value.tag.name, fbtMacroTags)))
   );
 }
 
 function isFbtJsxChild(
-  macroTagsCalls: Set<IdentifierId>,
+  fbtValues: Set<IdentifierId>,
   lvalue: Place | null,
-  value: InstructionValue,
+  value: ReactiveValue,
 ): boolean {
   return (
     (value.kind === 'JsxExpression' || value.kind === 'JsxFragment') &&
     lvalue !== null &&
-    macroTagsCalls.has(lvalue.identifier.id)
+    fbtValues.has(lvalue.identifier.id)
   );
 }
 

compiler/packages/babel-plugin-react-compiler/src/ReactiveScopes/PruneAlwaysInvalidatingScopes.ts

@@ -77,15 +77,6 @@ class Transform extends ReactiveFunctionTransform<boolean> {
         }
         break;
       }
-      case 'FinishMemoize': {
-        if (
-          !withinScope &&
-          this.alwaysInvalidatingValues.has(value.decl.identifier)
-        ) {
-          value.pruned = true;
-        }
-        break;
-      }
     }
     return {kind: 'keep'};
   }

compiler/packages/babel-plugin-react-compiler/src/Transform/NameAnonymousFunctions.ts

@@ -19,7 +19,7 @@ export function nameAnonymousFunctions(fn: HIRFunction): void {
   const parentName = fn.id;
   const functions = nameAnonymousFunctionsImpl(fn);
   function visit(node: Node, prefix: string): void {
-    if (node.generatedName != null && node.fn.nameHint == null) {
+    if (node.generatedName != null) {
       /**
        * Note that we don't generate a name for functions that already had one,
        * so we'll only add the prefix to anonymous functions regardless of
@@ -70,10 +70,6 @@ function nameAnonymousFunctionsImpl(fn: HIRFunction): Array<Node> {
           if (name != null && name.kind === 'named') {
             names.set(lvalue.identifier.id, name.value);
           }
-          const func = functions.get(value.place.identifier.id);
-          if (func != null) {
-            functions.set(lvalue.identifier.id, func);
-          }
           break;
         }
         case 'PropertyLoad': {
@@ -110,7 +106,6 @@ function nameAnonymousFunctionsImpl(fn: HIRFunction): Array<Node> {
           const variableName = value.lvalue.place.identifier.name;
           if (
             node != null &&
-            node.generatedName == null &&
             variableName != null &&
             variableName.kind === 'named'
           ) {
@@ -142,7 +137,7 @@ function nameAnonymousFunctionsImpl(fn: HIRFunction): Array<Node> {
               continue;
             }
             const node = functions.get(arg.identifier.id);
-            if (node != null && node.generatedName == null) {
+            if (node != null) {
               const generatedName =
                 fnArgCount > 1 ? `${calleeName}(arg${i})` : `${calleeName}()`;
               node.generatedName = generatedName;
@@ -157,7 +152,7 @@ function nameAnonymousFunctionsImpl(fn: HIRFunction): Array<Node> {
               continue;
             }
             const node = functions.get(attr.place.identifier.id);
-            if (node != null && node.generatedName == null) {
+            if (node != null) {
               const elementName =
                 value.tag.kind === 'BuiltinTag'
                   ? value.tag.name

compiler/packages/babel-plugin-react-compiler/src/TypeInference/InferTypes.ts

@@ -31,7 +31,6 @@ import {
   BuiltInObjectId,
   BuiltInPropsId,
   BuiltInRefValueId,
-  BuiltInSetStateId,
   BuiltInUseRefId,
 } from '../HIR/ObjectShape';
 import {eachInstructionLValue, eachInstructionOperand} from '../HIR/visitors';
@@ -277,16 +276,9 @@ function* generateInstructionTypes(
        * We should change Hook to a subtype of Function or change unifier logic.
        * (see https://github.com/facebook/react-forget/pull/1427)
        */
-      let shapeId: string | null = null;
-      if (env.config.enableTreatSetIdentifiersAsStateSetters) {
-        const name = getName(names, value.callee.identifier.id);
-        if (name.startsWith('set')) {
-          shapeId = BuiltInSetStateId;
-        }
-      }
       yield equation(value.callee.identifier.type, {
         kind: 'Function',
-        shapeId,
+        shapeId: null,
         return: returnType,
         isConstructor: false,
       });
@@ -393,7 +385,7 @@ function* generateInstructionTypes(
               shapeId: BuiltInArrayId,
             });
           } else {
-            continue;
+            break;
           }
         }
       } else {

compiler/packages/babel-plugin-react-compiler/src/Utils/TestUtils.ts

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {fromZodError} from 'zod-validation-error/v4';
+import {fromZodError} from 'zod-validation-error';
 import {CompilerError} from '../CompilerError';
 import {
   CompilationMode,
@@ -175,7 +175,7 @@ function parseConfigPragmaEnvironmentForTest(
   });
 }
 
-const testComplexPluginOptionDefaults: PluginOptions = {
+const testComplexPluginOptionDefaults: Partial<PluginOptions> = {
   gating: {
     source: 'ReactForgetFeatureFlag',
     importSpecifierName: 'isForgetEnabled_Fixtures',
@@ -188,6 +188,11 @@ export function parseConfigPragmaForTests(
     environment?: PartialEnvironmentConfig;
   },
 ): PluginOptions {
+  const overridePragma = parseConfigPragmaAsString(pragma);
+  if (overridePragma !== '') {
+    return parseConfigStringAsJS(overridePragma, defaults);
+  }
+
   const environment = parseConfigPragmaEnvironmentForTest(
     pragma,
     defaults.environment ?? {},
@@ -223,3 +228,100 @@ export function parseConfigPragmaForTests(
   }
   return parsePluginOptions(options);
 }
+
+export function parseConfigPragmaAsString(pragma: string): string {
+  // Check if it's in JS override format
+  for (const {key, value: val} of splitPragma(pragma)) {
+    if (key === 'OVERRIDE' && val != null) {
+      return val;
+    }
+  }
+  return '';
+}
+
+function parseConfigStringAsJS(
+  configString: string,
+  defaults: {
+    compilationMode: CompilationMode;
+    environment?: PartialEnvironmentConfig;
+  },
+): PluginOptions {
+  let parsedConfig: any;
+  try {
+    // Parse the JavaScript object literal
+    parsedConfig = new Function(`return ${configString}`)();
+  } catch (error) {
+    CompilerError.invariant(false, {
+      reason: 'Failed to parse config pragma as JavaScript object',
+      description: `Could not parse: ${configString}. Error: ${error}`,
+      details: [
+        {
+          kind: 'error',
+          loc: null,
+          message: null,
+        },
+      ],
+      suggestions: null,
+    });
+  }
+
+  const environment = parseConfigPragmaEnvironmentForTest(
+    '',
+    defaults.environment ?? {},
+  );
+
+  const options: Record<keyof PluginOptions, unknown> = {
+    ...defaultOptions,
+    panicThreshold: 'all_errors',
+    compilationMode: defaults.compilationMode,
+    environment,
+  };
+
+  // Apply parsed config, merging environment if it exists
+  if (parsedConfig.environment) {
+    const mergedEnvironment = {
+      ...(options.environment as Record<string, unknown>),
+      ...parsedConfig.environment,
+    };
+
+    // Validate environment config
+    const validatedEnvironment =
+      EnvironmentConfigSchema.safeParse(mergedEnvironment);
+    if (!validatedEnvironment.success) {
+      CompilerError.invariant(false, {
+        reason: 'Invalid environment configuration in config pragma',
+        description: `${fromZodError(validatedEnvironment.error)}`,
+        details: [
+          {
+            kind: 'error',
+            loc: null,
+            message: null,
+          },
+        ],
+        suggestions: null,
+      });
+    }
+
+    options.environment = validatedEnvironment.data;
+  }
+
+  // Apply other config options
+  for (const [key, value] of Object.entries(parsedConfig)) {
+    if (key === 'environment') {
+      continue;
+    }
+
+    if (hasOwnProperty(defaultOptions, key)) {
+      if (key === 'target' && value === 'donotuse_meta_internal') {
+        options[key] = {
+          kind: value,
+          runtimeModule: 'react',
+        };
+      } else {
+        options[key] = value;
+      }
+    }
+  }
+
+  return parsePluginOptions(options);
+}

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidateNoDerivedComputationsInEffects.ts

@@ -5,21 +5,223 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {CompilerError, SourceLocation} from '..';
+import {effect} from 'zod';
+import {CompilerError, Effect, ErrorSeverity, SourceLocation} from '..';
 import {ErrorCategory} from '../CompilerError';
 import {
   ArrayExpression,
+  BasicBlock,
   BlockId,
+  Identifier,
   FunctionExpression,
   HIRFunction,
   IdentifierId,
+  Instruction,
+  Place,
   isSetStateType,
   isUseEffectHookType,
+  isUseStateType,
+  IdentifierName,
+  GeneratedSource,
 } from '../HIR';
+import {printInstruction} from '../HIR/PrintHIR';
 import {
-  eachInstructionValueOperand,
+  eachInstructionOperand,
   eachTerminalOperand,
+  eachInstructionLValue,
+  eachPatternOperand,
 } from '../HIR/visitors';
+import {isMutable} from '../ReactiveScopes/InferReactiveScopeVariables';
+import {assertExhaustive} from '../Utils/utils';
+
+// TODO: Maybe I can consolidate some types
+type SetStateCall = {
+  loc: SourceLocation;
+  invalidDeps: DerivationMetadata;
+  setStateId: IdentifierId;
+};
+
+type TypeOfValue = 'ignored' | 'fromProps' | 'fromState' | 'fromPropsOrState';
+
+type SetStateName = string | undefined | null;
+
+type DerivationMetadata = {
+  typeOfValue: TypeOfValue;
+  // TODO: Rename to place
+  identifierPlace: Place;
+  sources: Place[];
+};
+
+// TODO: This needs refining
+type ErrorMetadata = {
+  errorType: TypeOfValue;
+  invalidDepInfo: string | undefined;
+  loc: SourceLocation;
+  setStateName: SetStateName;
+};
+
+function joinValue(
+  lvalueType: TypeOfValue,
+  valueType: TypeOfValue,
+): TypeOfValue {
+  if (lvalueType === 'ignored') return valueType;
+  if (valueType === 'ignored') return lvalueType;
+  if (lvalueType === valueType) return lvalueType;
+  return 'fromPropsOrState';
+}
+
+function updateDerivationMetadata(
+  target: Place,
+  sources: DerivationMetadata[],
+  typeOfValue: TypeOfValue,
+  derivedTuple: Map<IdentifierId, DerivationMetadata>,
+): void {
+  let newValue: DerivationMetadata = {
+    identifierPlace: target,
+    sources: [],
+    typeOfValue: typeOfValue,
+  };
+
+  for (const source of sources) {
+    // If the identifier of the source is a promoted identifier, then
+    // we should set the target as the source.
+    if (source.identifierPlace.identifier.name?.kind === 'promoted') {
+      newValue.sources.push(target);
+    } else {
+      newValue.sources.push(...source.sources);
+    }
+  }
+  derivedTuple.set(target.identifier.id, newValue);
+}
+
+function parseInstr(
+  instr: Instruction,
+  derivedTuple: Map<IdentifierId, DerivationMetadata>,
+  setStateCalls: Map<SetStateName, Place[]>,
+) {
+  // console.log(printInstruction(instr));
+  // console.log(instr);
+  let typeOfValue: TypeOfValue = 'ignored';
+
+  // TODO: Not sure if this will catch every time we create a new useState
+  if (
+    instr.value.kind === 'Destructure' &&
+    instr.value.lvalue.pattern.kind === 'ArrayPattern' &&
+    isUseStateType(instr.value.value.identifier)
+  ) {
+    const value = instr.value.lvalue.pattern.items[0];
+    if (value.kind === 'Identifier') {
+      derivedTuple.set(value.identifier.id, {
+        identifierPlace: value,
+        sources: [value],
+        typeOfValue: 'fromState',
+      });
+    }
+  }
+
+  if (
+    instr.value.kind === 'CallExpression' &&
+    isSetStateType(instr.value.callee.identifier) &&
+    instr.value.args.length === 1 &&
+    instr.value.args[0].kind === 'Identifier' &&
+    instr.value.callee.loc !== GeneratedSource
+  ) {
+    if (setStateCalls.has(instr.value.callee.loc.identifierName)) {
+      setStateCalls
+        .get(instr.value.callee.loc.identifierName)!
+        .push(instr.value.callee);
+    } else {
+      setStateCalls.set(instr.value.callee.loc.identifierName, [
+        instr.value.callee,
+      ]);
+    }
+  }
+
+  let sources: DerivationMetadata[] = [];
+  for (const operand of eachInstructionOperand(instr)) {
+    const opSource = derivedTuple.get(operand.identifier.id);
+    if (opSource === undefined) {
+      continue;
+    }
+
+    typeOfValue = joinValue(typeOfValue, opSource.typeOfValue);
+    sources.push(opSource);
+  }
+
+  if (typeOfValue !== 'ignored') {
+    for (const lvalue of eachInstructionLValue(instr)) {
+      updateDerivationMetadata(lvalue, sources, typeOfValue, derivedTuple);
+    }
+
+    for (const operand of eachInstructionOperand(instr)) {
+      switch (operand.effect) {
+        case Effect.Capture:
+        case Effect.Store:
+        case Effect.ConditionallyMutate:
+        case Effect.ConditionallyMutateIterator:
+        case Effect.Mutate: {
+          if (isMutable(instr, operand)) {
+            updateDerivationMetadata(
+              operand,
+              sources,
+              typeOfValue,
+              derivedTuple,
+            );
+          }
+          break;
+        }
+        case Effect.Freeze:
+        case Effect.Read: {
+          // no-op
+          break;
+        }
+        case Effect.Unknown: {
+          CompilerError.invariant(false, {
+            reason: 'Unexpected unknown effect',
+            description: null,
+            loc: operand.loc,
+            suggestions: null,
+          });
+        }
+        default: {
+          assertExhaustive(
+            operand.effect,
+            `Unexpected effect kind \`${operand.effect}\``,
+          );
+        }
+      }
+    }
+  }
+}
+
+function parseBlockPhi(
+  block: BasicBlock,
+  derivedTuple: Map<IdentifierId, DerivationMetadata>,
+) {
+  for (const phi of block.phis) {
+    for (const operand of phi.operands.values()) {
+      const source = derivedTuple.get(operand.identifier.id);
+      if (source !== undefined && source.typeOfValue === 'fromProps') {
+        if (
+          source.identifierPlace.identifier.name === null ||
+          source.identifierPlace.identifier.name?.kind === 'promoted'
+        ) {
+          derivedTuple.set(phi.place.identifier.id, {
+            identifierPlace: phi.place,
+            sources: [phi.place],
+            typeOfValue: 'fromProps',
+          });
+        } else {
+          derivedTuple.set(phi.place.identifier.id, {
+            identifierPlace: phi.place,
+            sources: source.sources,
+            typeOfValue: 'fromProps',
+          });
+        }
+      }
+    }
+  }
+}
 
 /**
  * Validates that useEffect is not used for derived computations which could/should
@@ -48,12 +250,54 @@ export function validateNoDerivedComputationsInEffects(fn: HIRFunction): void {
   const candidateDependencies: Map<IdentifierId, ArrayExpression> = new Map();
   const functions: Map<IdentifierId, FunctionExpression> = new Map();
   const locals: Map<IdentifierId, IdentifierId> = new Map();
+  const derivedTuple: Map<IdentifierId, DerivationMetadata> = new Map();
 
-  const errors = new CompilerError();
+  const effectSetStates: Map<SetStateName, Place[]> = new Map();
+  const setStateCalls: Map<SetStateName, Place[]> = new Map();
+
+  const errors: ErrorMetadata[] = [];
+
+  if (fn.fnType === 'Hook') {
+    for (const param of fn.params) {
+      if (param.kind === 'Identifier') {
+        derivedTuple.set(param.identifier.id, {
+          identifierPlace: param,
+          sources: [param],
+          typeOfValue: 'fromProps',
+        });
+      }
+    }
+  } else if (fn.fnType === 'Component') {
+    const props = fn.params[0];
+    if (props != null && props.kind === 'Identifier') {
+      derivedTuple.set(props.identifier.id, {
+        identifierPlace: props,
+        sources: [props],
+        typeOfValue: 'fromProps',
+      });
+    }
+  }
 
   for (const block of fn.body.blocks.values()) {
+    parseBlockPhi(block, derivedTuple);
+
     for (const instr of block.instructions) {
       const {lvalue, value} = instr;
+
+      parseInstr(instr, derivedTuple, setStateCalls);
+
+      /*
+       * Special case for function expressions, we need to parse nested instructions
+       * TODO: Can there be more recursive levels?
+       */
+      if (value.kind === 'FunctionExpression') {
+        for (const [, block] of value.loweredFunc.func.body.blocks) {
+          for (const instr of block.instructions) {
+            parseInstr(instr, derivedTuple, setStateCalls);
+          }
+        }
+      }
+
       if (value.kind === 'LoadLocal') {
         locals.set(lvalue.identifier.id, value.place.identifier.id);
       } else if (value.kind === 'ArrayExpression') {
@@ -66,6 +310,7 @@ export function validateNoDerivedComputationsInEffects(fn: HIRFunction): void {
       ) {
         const callee =
           value.kind === 'CallExpression' ? value.callee : value.property;
+
         if (
           isUseEffectHookType(callee.identifier) &&
           value.args.length === 2 &&
@@ -97,6 +342,8 @@ export function validateNoDerivedComputationsInEffects(fn: HIRFunction): void {
             validateEffect(
               effectFunction.loweredFunc.func,
               dependencies,
+              derivedTuple,
+              effectSetStates,
               errors,
             );
           }
@@ -104,43 +351,99 @@ export function validateNoDerivedComputationsInEffects(fn: HIRFunction): void {
       }
     }
   }
-  if (errors.hasAnyErrors()) {
-    throw errors;
+
+  const throwableErrors = new CompilerError();
+  for (const error of errors) {
+    let reason;
+    let description = '';
+    // TODO: Not sure if this is robust enough.
+    /*
+     * If we use a setState from an invalid useEffect elsewhere then we probably have to
+     * hoist state up, else we should calculate in render
+     */
+    if (
+      setStateCalls.get(error.setStateName)?.length !=
+        effectSetStates.get(error.setStateName)?.length &&
+      error.errorType !== 'fromState'
+    ) {
+      reason =
+        'Consider lifting state up to the parent component to make this a controlled component. (https://react.dev/learn/you-might-not-need-an-effect#adjusting-some-state-when-a-prop-changes)';
+    } else {
+      reason =
+        'You may not need this effect. Values derived from state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)';
+    }
+
+    throwableErrors.push({
+      reason: reason,
+      description: `You are using invalid dependencies: \n\n${error.invalidDepInfo}`,
+      severity: ErrorSeverity.InvalidReact,
+      loc: error.loc,
+    });
+  }
+
+  if (throwableErrors.hasAnyErrors()) {
+    throw throwableErrors;
   }
 }
 
 function validateEffect(
   effectFunction: HIRFunction,
   effectDeps: Array<IdentifierId>,
-  errors: CompilerError,
+  derivedTuple: Map<IdentifierId, DerivationMetadata>,
+  effectSetStates: Map<SetStateName, Place[]>,
+  errors: ErrorMetadata[],
 ): void {
+  /*
+   * TODO: This makes it so we only capture single line useEffects.
+   * We should be able to capture multiline as well
+   */
   for (const operand of effectFunction.context) {
     if (isSetStateType(operand.identifier)) {
       continue;
     } else if (effectDeps.find(dep => dep === operand.identifier.id) != null) {
       continue;
+    } else if (derivedTuple.has(operand.identifier.id)) {
+      continue;
     } else {
       // Captured something other than the effect dep or setState
       return;
     }
   }
+
+  // TODO: This might be wrong gotta double check
+  let hasInvalidDep = false;
   for (const dep of effectDeps) {
+    const depMetadata = derivedTuple.get(dep);
     if (
-      effectFunction.context.find(operand => operand.identifier.id === dep) ==
-      null
+      effectFunction.context.find(operand => operand.identifier.id === dep) !=
+        null ||
+      (depMetadata !== undefined && depMetadata.typeOfValue !== 'ignored')
     ) {
-      // effect dep wasn't actually used in the function
-      return;
+      hasInvalidDep = true;
     }
   }
 
-  const seenBlocks: Set<BlockId> = new Set();
-  const values: Map<IdentifierId, Array<IdentifierId>> = new Map();
-  for (const dep of effectDeps) {
-    values.set(dep, [dep]);
+  if (!hasInvalidDep) {
+    console.log('early return 2');
+    // effect dep wasn't actually used in the function
+    return;
   }
 
-  const setStateLocations: Array<SourceLocation> = [];
+  const seenBlocks: Set<BlockId> = new Set();
+  // This variable is suspicious maybe we don't need it?
+  const values: Map<IdentifierId, Array<IdentifierId>> = new Map();
+  const effectInvalidlyDerived: Map<IdentifierId, DerivationMetadata> =
+    new Map();
+
+  for (const dep of effectDeps) {
+    values.set(dep, [dep]);
+    const depMetadata = derivedTuple.get(dep);
+    if (depMetadata !== undefined) {
+      effectInvalidlyDerived.set(dep, depMetadata);
+    }
+  }
+
+  const setStateCallsInEffect: Array<SetStateCall> = [];
   for (const block of effectFunction.body.blocks.values()) {
     for (const pred of block.preds) {
       if (!seenBlocks.has(pred)) {
@@ -148,21 +451,29 @@ function validateEffect(
         return;
       }
     }
-    for (const phi of block.phis) {
-      const aggregateDeps: Set<IdentifierId> = new Set();
-      for (const operand of phi.operands.values()) {
-        const deps = values.get(operand.identifier.id);
-        if (deps != null) {
-          for (const dep of deps) {
-            aggregateDeps.add(dep);
-          }
+
+    parseBlockPhi(block, effectInvalidlyDerived);
+
+    for (const instr of block.instructions) {
+      if (
+        instr.value.kind === 'CallExpression' &&
+        isSetStateType(instr.value.callee.identifier) &&
+        instr.value.args.length === 1 &&
+        instr.value.args[0].kind === 'Identifier' &&
+        instr.value.callee.loc !== GeneratedSource &&
+        instr.value.callee.loc.identifierName !== undefined &&
+        instr.value.callee.loc.identifierName !== null
+      ) {
+        if (effectSetStates.has(instr.value.callee.loc.identifierName)) {
+          effectSetStates
+            .get(instr.value.callee.loc.identifierName)!
+            .push(instr.value.callee);
+        } else {
+          effectSetStates.set(instr.value.callee.loc.identifierName, [
+            instr.value.callee,
+          ]);
         }
       }
-      if (aggregateDeps.size !== 0) {
-        values.set(phi.place.identifier.id, Array.from(aggregateDeps));
-      }
-    }
-    for (const instr of block.instructions) {
       switch (instr.value.kind) {
         case 'Primitive':
         case 'JSXText':
@@ -183,7 +494,7 @@ function validateEffect(
         case 'CallExpression':
         case 'MethodCall': {
           const aggregateDeps: Set<IdentifierId> = new Set();
-          for (const operand of eachInstructionValueOperand(instr.value)) {
+          for (const operand of eachInstructionOperand(instr)) {
             const deps = values.get(operand.identifier.id);
             if (deps != null) {
               for (const dep of deps) {
@@ -201,38 +512,63 @@ function validateEffect(
             instr.value.args.length === 1 &&
             instr.value.args[0].kind === 'Identifier'
           ) {
-            const deps = values.get(instr.value.args[0].identifier.id);
-            if (deps != null && new Set(deps).size === effectDeps.length) {
-              setStateLocations.push(instr.value.callee.loc);
-            } else {
-              // doesn't depend on any deps
-              return;
+            const invalidDeps = derivedTuple.get(
+              instr.value.args[0].identifier.id,
+            );
+
+            if (invalidDeps !== undefined) {
+              setStateCallsInEffect.push({
+                loc: instr.value.callee.loc,
+                setStateId: instr.value.callee.identifier.id,
+                invalidDeps: invalidDeps,
+              });
             }
           }
           break;
         }
         default: {
+          console.log('early return 4');
           return;
         }
       }
     }
+
     for (const operand of eachTerminalOperand(block.terminal)) {
       if (values.has(operand.identifier.id)) {
-        //
         return;
       }
     }
     seenBlocks.add(block.id);
   }
 
-  for (const loc of setStateLocations) {
+  for (const call of setStateCallsInEffect) {
+    const placeNames = call.invalidDeps.sources
+      .map(place => place.identifier.name?.value)
+      .join(', ');
+
+    let sourceNames = '';
+    let invalidDepInfo = '';
+    console.log(call.invalidDeps);
+    if (call.invalidDeps.typeOfValue === 'fromProps') {
+      sourceNames += `[${placeNames}], `;
+      sourceNames = sourceNames.slice(0, -2);
+      invalidDepInfo = sourceNames
+        ? `Invalid deps from props ${sourceNames}`
+        : '';
+    } else if (call.invalidDeps.typeOfValue === 'fromState') {
+      sourceNames += `[${placeNames}], `;
+      sourceNames = sourceNames.slice(0, -2);
+      invalidDepInfo = sourceNames
+        ? `Invalid deps from local state: ${sourceNames}`
+        : '';
+    }
+
     errors.push({
-      category: ErrorCategory.EffectDerivationsOfState,
-      reason:
-        'Values derived from props and state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)',
-      description: null,
-      loc,
-      suggestions: null,
+      errorType: call.invalidDeps.typeOfValue,
+      invalidDepInfo: invalidDepInfo,
+      loc: call.loc,
+      setStateName:
+        call.loc !== GeneratedSource ? call.loc.identifierName : undefined,
     });
   }
 }

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidateNoRefAccessInRender.ts

@@ -639,55 +639,12 @@ function validateNoRefAccessInRenderImpl(
           case 'StartMemoize':
           case 'FinishMemoize':
             break;
-          case 'LoadGlobal': {
-            if (instr.value.binding.name === 'undefined') {
-              env.set(instr.lvalue.identifier.id, {kind: 'Nullable'});
-            }
-            break;
-          }
           case 'Primitive': {
             if (instr.value.value == null) {
               env.set(instr.lvalue.identifier.id, {kind: 'Nullable'});
             }
             break;
           }
-          case 'UnaryExpression': {
-            if (instr.value.operator === '!') {
-              const value = env.get(instr.value.value.identifier.id);
-              const refId =
-                value?.kind === 'RefValue' && value.refId != null
-                  ? value.refId
-                  : null;
-              if (refId !== null) {
-                /*
-                 * Record an error suggesting the `if (ref.current == null)` pattern,
-                 * but also record the lvalue as a guard so that we don't emit a second
-                 * error for the write to the ref
-                 */
-                env.set(instr.lvalue.identifier.id, {kind: 'Guard', refId});
-                errors.pushDiagnostic(
-                  CompilerDiagnostic.create({
-                    category: ErrorCategory.Refs,
-                    reason: 'Cannot access refs during render',
-                    description: ERROR_DESCRIPTION,
-                  })
-                    .withDetails({
-                      kind: 'error',
-                      loc: instr.value.value.loc,
-                      message: `Cannot access ref value during render`,
-                    })
-                    .withDetails({
-                      kind: 'hint',
-                      message:
-                        'To initialize a ref only once, check that the ref is null with the pattern `if (ref.current == null) { ref.current = ... }`',
-                    }),
-                );
-                break;
-              }
-            }
-            validateNoRefValueAccess(errors, env, instr.value.value);
-            break;
-          }
           case 'BinaryExpression': {
             const left = env.get(instr.value.left.identifier.id);
             const right = env.get(instr.value.right.identifier.id);

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidateNoSetStateInEffects.ts

@@ -11,23 +11,16 @@ import {
   ErrorCategory,
 } from '../CompilerError';
 import {
-  Environment,
   HIRFunction,
   IdentifierId,
   isSetStateType,
   isUseEffectHookType,
   isUseInsertionEffectHookType,
   isUseLayoutEffectHookType,
-  isUseRefType,
-  isRefValueType,
   Place,
 } from '../HIR';
-import {
-  eachInstructionLValue,
-  eachInstructionValueOperand,
-} from '../HIR/visitors';
+import {eachInstructionValueOperand} from '../HIR/visitors';
 import {Result} from '../Utils/Result';
-import {Iterable_some} from '../Utils/utils';
 
 /**
  * Validates against calling setState in the body of an effect (useEffect and friends),
@@ -39,7 +32,6 @@ import {Iterable_some} from '../Utils/utils';
  */
 export function validateNoSetStateInEffects(
   fn: HIRFunction,
-  env: Environment,
 ): Result<void, CompilerError> {
   const setStateFunctions: Map<IdentifierId, Place> = new Map();
   const errors = new CompilerError();
@@ -80,7 +72,6 @@ export function validateNoSetStateInEffects(
             const callee = getSetStateCall(
               instr.value.loweredFunc.func,
               setStateFunctions,
-              env,
             );
             if (callee !== null) {
               setStateFunctions.set(instr.lvalue.identifier.id, callee);
@@ -138,42 +129,9 @@ export function validateNoSetStateInEffects(
 function getSetStateCall(
   fn: HIRFunction,
   setStateFunctions: Map<IdentifierId, Place>,
-  env: Environment,
 ): Place | null {
-  const refDerivedValues: Set<IdentifierId> = new Set();
-
-  const isDerivedFromRef = (place: Place): boolean => {
-    return (
-      refDerivedValues.has(place.identifier.id) ||
-      isUseRefType(place.identifier) ||
-      isRefValueType(place.identifier)
-    );
-  };
-
   for (const [, block] of fn.body.blocks) {
     for (const instr of block.instructions) {
-      if (env.config.enableAllowSetStateFromRefsInEffects) {
-        const hasRefOperand = Iterable_some(
-          eachInstructionValueOperand(instr.value),
-          isDerivedFromRef,
-        );
-
-        if (hasRefOperand) {
-          for (const lvalue of eachInstructionLValue(instr)) {
-            refDerivedValues.add(lvalue.identifier.id);
-          }
-        }
-
-        if (
-          instr.value.kind === 'PropertyLoad' &&
-          instr.value.property === 'current' &&
-          (isUseRefType(instr.value.object.identifier) ||
-            isRefValueType(instr.value.object.identifier))
-        ) {
-          refDerivedValues.add(instr.lvalue.identifier.id);
-        }
-      }
-
       switch (instr.value.kind) {
         case 'LoadLocal': {
           if (setStateFunctions.has(instr.value.place.identifier.id)) {
@@ -203,21 +161,6 @@ function getSetStateCall(
             isSetStateType(callee.identifier) ||
             setStateFunctions.has(callee.identifier.id)
           ) {
-            if (env.config.enableAllowSetStateFromRefsInEffects) {
-              const arg = instr.value.args.at(0);
-              if (
-                arg !== undefined &&
-                arg.kind === 'Identifier' &&
-                refDerivedValues.has(arg.identifier.id)
-              ) {
-                /**
-                 * The one special case where we allow setStates in effects is in the very specific
-                 * scenario where the value being set is derived from a ref. For example this may
-                 * be needed when initial layout measurements from refs need to be stored in state.
-                 */
-                return null;
-              }
-            }
             /*
              * TODO: once we support multiple locations per error, we should link to the
              * original Place in the case that setStateFunction.has(callee)

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidateUseMemo.ts

@@ -10,37 +10,16 @@ import {
   CompilerError,
   ErrorCategory,
 } from '../CompilerError';
-import {
-  FunctionExpression,
-  HIRFunction,
-  IdentifierId,
-  SourceLocation,
-} from '../HIR';
-import {
-  eachInstructionValueOperand,
-  eachTerminalOperand,
-} from '../HIR/visitors';
+import {FunctionExpression, HIRFunction, IdentifierId} from '../HIR';
 import {Result} from '../Utils/Result';
 
 export function validateUseMemo(fn: HIRFunction): Result<void, CompilerError> {
   const errors = new CompilerError();
-  const voidMemoErrors = new CompilerError();
   const useMemos = new Set<IdentifierId>();
   const react = new Set<IdentifierId>();
   const functions = new Map<IdentifierId, FunctionExpression>();
-  const unusedUseMemos = new Map<IdentifierId, SourceLocation>();
   for (const [, block] of fn.body.blocks) {
     for (const {lvalue, value} of block.instructions) {
-      if (unusedUseMemos.size !== 0) {
-        /**
-         * Most of the time useMemo results are referenced immediately. Don't bother
-         * scanning instruction operands for useMemos unless there is an as-yet-unused
-         * useMemo.
-         */
-        for (const operand of eachInstructionValueOperand(value)) {
-          unusedUseMemos.delete(operand.identifier.id);
-        }
-      }
       switch (value.kind) {
         case 'LoadGlobal': {
           if (value.binding.name === 'useMemo') {
@@ -66,8 +45,10 @@ export function validateUseMemo(fn: HIRFunction): Result<void, CompilerError> {
         case 'CallExpression': {
           // Is the function being called useMemo, with at least 1 argument?
           const callee =
-            value.kind === 'CallExpression' ? value.callee : value.property;
-          const isUseMemo = useMemos.has(callee.identifier.id);
+            value.kind === 'CallExpression'
+              ? value.callee.identifier.id
+              : value.property.identifier.id;
+          const isUseMemo = useMemos.has(callee);
           if (!isUseMemo || value.args.length === 0) {
             continue;
           }
@@ -123,103 +104,10 @@ export function validateUseMemo(fn: HIRFunction): Result<void, CompilerError> {
             );
           }
 
-          validateNoContextVariableAssignment(body.loweredFunc.func, errors);
-
-          if (fn.env.config.validateNoVoidUseMemo) {
-            if (!hasNonVoidReturn(body.loweredFunc.func)) {
-              voidMemoErrors.pushDiagnostic(
-                CompilerDiagnostic.create({
-                  category: ErrorCategory.VoidUseMemo,
-                  reason: 'useMemo() callbacks must return a value',
-                  description: `This useMemo() callback doesn't return a value. useMemo() is for computing and caching values, not for arbitrary side effects`,
-                  suggestions: null,
-                }).withDetails({
-                  kind: 'error',
-                  loc: body.loc,
-                  message: 'useMemo() callbacks must return a value',
-                }),
-              );
-            } else {
-              unusedUseMemos.set(lvalue.identifier.id, callee.loc);
-            }
-          }
           break;
         }
       }
     }
-    if (unusedUseMemos.size !== 0) {
-      for (const operand of eachTerminalOperand(block.terminal)) {
-        unusedUseMemos.delete(operand.identifier.id);
-      }
-    }
   }
-  if (unusedUseMemos.size !== 0) {
-    /**
-     * Basic check for unused memos, where the result of the call is never referenced. This runs
-     * before DCE so it's more of an AST-level check that something, _anything_, cares about the value.
-     *
-     * This is easy to defeat with e.g. `const _ = useMemo(...)` but it at least gives us something to teach.
-     * Even a DCE-based version could be bypassed with `noop(useMemo(...))`.
-     */
-    for (const loc of unusedUseMemos.values()) {
-      voidMemoErrors.pushDiagnostic(
-        CompilerDiagnostic.create({
-          category: ErrorCategory.VoidUseMemo,
-          reason: 'useMemo() result is unused',
-          description: `This useMemo() value is unused. useMemo() is for computing and caching values, not for arbitrary side effects`,
-          suggestions: null,
-        }).withDetails({
-          kind: 'error',
-          loc,
-          message: 'useMemo() result is unused',
-        }),
-      );
-    }
-  }
-  fn.env.logErrors(voidMemoErrors.asResult());
   return errors.asResult();
 }
-
-function validateNoContextVariableAssignment(
-  fn: HIRFunction,
-  errors: CompilerError,
-): void {
-  for (const block of fn.body.blocks.values()) {
-    for (const instr of block.instructions) {
-      const value = instr.value;
-      switch (value.kind) {
-        case 'StoreContext': {
-          errors.pushDiagnostic(
-            CompilerDiagnostic.create({
-              category: ErrorCategory.UseMemo,
-              reason:
-                'useMemo() callbacks may not reassign variables declared outside of the callback',
-              description:
-                'useMemo() callbacks must be pure functions and cannot reassign variables defined outside of the callback function',
-              suggestions: null,
-            }).withDetails({
-              kind: 'error',
-              loc: value.lvalue.place.loc,
-              message: 'Cannot reassign variable',
-            }),
-          );
-          break;
-        }
-      }
-    }
-  }
-}
-
-function hasNonVoidReturn(func: HIRFunction): boolean {
-  for (const [, block] of func.body.blocks) {
-    if (block.terminal.kind === 'return') {
-      if (
-        block.terminal.returnVariant === 'Explicit' ||
-        block.terminal.returnVariant === 'Implicit'
-      ) {
-        return true;
-      }
-    }
-  }
-  return false;
-}

compiler/packages/babel-plugin-react-compiler/src/__tests__/envConfig-test.ts

@@ -20,7 +20,7 @@ describe('parseConfigPragma()', () => {
         validateHooksUsage: 1,
       } as any);
     }).toThrowErrorMatchingInlineSnapshot(
-      `"Error: Could not validate environment config. Update React Compiler config to fix the error. Validation error: Invalid input: expected boolean, received number at "validateHooksUsage"."`,
+      `"Error: Could not validate environment config. Update React Compiler config to fix the error. Validation error: Expected boolean, received number at "validateHooksUsage"."`,
     );
   });
 
@@ -38,7 +38,7 @@ describe('parseConfigPragma()', () => {
         ],
       } as any);
     }).toThrowErrorMatchingInlineSnapshot(
-      `"Error: Could not validate environment config. Update React Compiler config to fix the error. Validation error: AutodepsIndex must be > 0 at "inferEffectDependencies[0].autodepsIndex"."`,
+      `"Error: Could not validate environment config. Update React Compiler config to fix the error. Validation error: autodepsIndex must be > 0 at "inferEffectDependencies[0].autodepsIndex"."`,
     );
   });
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allocating-primitive-as-dep.expect.md

@@ -2,7 +2,6 @@
 ## Input
 
 ```javascript
-// @enablePreserveExistingMemoizationGuarantees:false
 // bar(props.b) is an allocating expression that produces a primitive, which means
 // that Forget should memoize it.
 // Correctness:
@@ -17,8 +16,7 @@ function AllocatingPrimitiveAsDep(props) {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @enablePreserveExistingMemoizationGuarantees:false
-// bar(props.b) is an allocating expression that produces a primitive, which means
+import { c as _c } from "react/compiler-runtime"; // bar(props.b) is an allocating expression that produces a primitive, which means
 // that Forget should memoize it.
 // Correctness:
 //   - y depends on either bar(props.b) or bar(props.b) + 1

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allocating-primitive-as-dep.js

@@ -1,4 +1,3 @@
-// @enablePreserveExistingMemoizationGuarantees:false
 // bar(props.b) is an allocating expression that produces a primitive, which means
 // that Forget should memoize it.
 // Correctness:

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allow-modify-global-in-callback-jsx.expect.md

@@ -2,7 +2,6 @@
 ## Input
 
 ```javascript
-// @enablePreserveExistingMemoizationGuarantees:false
 import {useMemo} from 'react';
 
 const someGlobal = {value: 0};
@@ -33,7 +32,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @enablePreserveExistingMemoizationGuarantees:false
+import { c as _c } from "react/compiler-runtime";
 import { useMemo } from "react";
 
 const someGlobal = { value: 0 };

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allow-modify-global-in-callback-jsx.js

@@ -1,4 +1,3 @@
-// @enablePreserveExistingMemoizationGuarantees:false
 import {useMemo} from 'react';
 
 const someGlobal = {value: 0};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allow-ref-initialization-undefined.expect.md

@@ -1,42 +0,0 @@
-
-## Input
-
-```javascript
-//@flow
-import {useRef} from 'react';
-
-component C() {
-  const r = useRef(null);
-  if (r.current == undefined) {
-    r.current = 1;
-  }
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: C,
-  params: [{}],
-};
-
-```
-
-## Code
-
-```javascript
-import { useRef } from "react";
-
-function C() {
-  const r = useRef(null);
-  if (r.current == undefined) {
-    r.current = 1;
-  }
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: C,
-  params: [{}],
-};
-
-```
-      
-### Eval output
-(kind: ok) 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allow-ref-initialization-undefined.js

@@ -1,14 +0,0 @@
-//@flow
-import {useRef} from 'react';
-
-component C() {
-  const r = useRef(null);
-  if (r.current == undefined) {
-    r.current = 1;
-  }
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: C,
-  params: [{}],
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/computed-load-primitive-as-dependency.expect.md

@@ -2,7 +2,6 @@
 ## Input
 
 ```javascript
-// @enablePreserveExistingMemoizationGuarantees:false
 function Component(props) {
   let a = foo();
   // freeze `a` so we know the next line cannot mutate it
@@ -18,7 +17,7 @@ function Component(props) {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @enablePreserveExistingMemoizationGuarantees:false
+import { c as _c } from "react/compiler-runtime";
 function Component(props) {
   const $ = _c(2);
   const a = foo();

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/computed-load-primitive-as-dependency.js

@@ -1,4 +1,3 @@
-// @enablePreserveExistingMemoizationGuarantees:false
 function Component(props) {
   let a = foo();
   // freeze `a` so we know the next line cannot mutate it

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/constant-propagation-template-literal.expect.md

@@ -2,7 +2,6 @@
 ## Input
 
 ```javascript
-// @enablePreserveExistingMemoizationGuarantees:false
 import {Stringify, identity} from 'shared-runtime';
 
 function foo() {
@@ -65,7 +64,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @enablePreserveExistingMemoizationGuarantees:false
+import { c as _c } from "react/compiler-runtime";
 import { Stringify, identity } from "shared-runtime";
 
 function foo() {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/constant-propagation-template-literal.js

@@ -1,4 +1,3 @@
-// @enablePreserveExistingMemoizationGuarantees:false
 import {Stringify, identity} from 'shared-runtime';
 
 function foo() {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/context-variable-as-jsx-element-tag.expect.md

@@ -2,7 +2,6 @@
 ## Input
 
 ```javascript
-// @enablePreserveExistingMemoizationGuarantees:false
 import {useMemo} from 'react';
 import {Stringify} from 'shared-runtime';
 
@@ -26,7 +25,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @enablePreserveExistingMemoizationGuarantees:false
+import { c as _c } from "react/compiler-runtime";
 import { useMemo } from "react";
 import { Stringify } from "shared-runtime";
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/context-variable-as-jsx-element-tag.js

@@ -1,4 +1,3 @@
-// @enablePreserveExistingMemoizationGuarantees:false
 import {useMemo} from 'react';
 import {Stringify} from 'shared-runtime';
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/destructure-direct-reassignment.expect.md

@@ -2,7 +2,6 @@
 ## Input
 
 ```javascript
-// @enablePreserveExistingMemoizationGuarantees:false
 function foo(props) {
   let x, y;
   ({x, y} = {x: props.a, y: props.b});
@@ -22,7 +21,6 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-// @enablePreserveExistingMemoizationGuarantees:false
 function foo(props) {
   let x;
   let y;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/destructure-direct-reassignment.js

@@ -1,4 +1,3 @@
-// @enablePreserveExistingMemoizationGuarantees:false
 function foo(props) {
   let x, y;
   ({x, y} = {x: props.a, y: props.b});

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.bug-invariant-expected-consistent-destructuring.expect.md

@@ -29,7 +29,7 @@ Found 1 error:
 
 Invariant: Expected consistent kind for destructuring
 
-Other places were `Reassign` but 'mutate? #t8$47[7:9]{reactive}' is const.
+Other places were `Reassign` but 'mutate? #t8$46[7:9]{reactive}' is const.
 
 error.bug-invariant-expected-consistent-destructuring.ts:9:9
    7 |

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-derived-computation-in-effect.expect.md

@@ -24,13 +24,15 @@ function BadExample() {
 ```
 Found 1 error:
 
-Error: Values derived from props and state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)
+Error: You may not need this effect. Values derived from state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)
+
+This effect updates state based on other state values. Consider calculating this value directly during render.
 
 error.invalid-derived-computation-in-effect.ts:9:4
    7 |   const [fullName, setFullName] = useState('');
    8 |   useEffect(() => {
 >  9 |     setFullName(capitalize(firstName + ' ' + lastName));
-     |     ^^^^^^^^^^^ Values derived from props and state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)
+     |     ^^^^^^^^^^^ You may not need this effect. Values derived from state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)
   10 |   }, [firstName, lastName]);
   11 |
   12 |   return <div>{fullName}</div>;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-reassign-variable-in-usememo.expect.md

@@ -1,38 +0,0 @@
-
-## Input
-
-```javascript
-function Component() {
-  let x;
-  const y = useMemo(() => {
-    let z;
-    x = [];
-    z = true;
-    return z;
-  }, []);
-  return [x, y];
-}
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Error: useMemo() callbacks may not reassign variables declared outside of the callback
-
-useMemo() callbacks must be pure functions and cannot reassign variables defined outside of the callback function.
-
-error.invalid-reassign-variable-in-usememo.ts:5:4
-  3 |   const y = useMemo(() => {
-  4 |     let z;
-> 5 |     x = [];
-    |     ^ Cannot reassign variable
-  6 |     z = true;
-  7 |     return z;
-  8 |   }, []);
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-reassign-variable-in-usememo.js

@@ -1,10 +0,0 @@
-function Component() {
-  let x;
-  const y = useMemo(() => {
-    let z;
-    x = [];
-    z = true;
-    return z;
-  }, []);
-  return [x, y];
-}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-ref-access-render-unary.expect.md

@@ -1,78 +0,0 @@
-
-## Input
-
-```javascript
-//@flow
-import {useRef} from 'react';
-
-component C() {
-  const r = useRef(null);
-  const current = !r.current;
-  return <div>{current}</div>;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: C,
-  params: [{}],
-};
-
-```
-
-
-## Error
-
-```
-Found 4 errors:
-
-Error: Cannot access refs during render
-
-React refs are values that are not needed for rendering. Refs should only be accessed outside of render, such as in event handlers or effects. Accessing a ref value (the `current` property) during render can cause your component not to update as expected (https://react.dev/reference/react/useRef).
-
-  4 | component C() {
-  5 |   const r = useRef(null);
-> 6 |   const current = !r.current;
-    |                    ^^^^^^^^^ Cannot access ref value during render
-  7 |   return <div>{current}</div>;
-  8 | }
-  9 |
-
-To initialize a ref only once, check that the ref is null with the pattern `if (ref.current == null) { ref.current = ... }`
-
-Error: Cannot access refs during render
-
-React refs are values that are not needed for rendering. Refs should only be accessed outside of render, such as in event handlers or effects. Accessing a ref value (the `current` property) during render can cause your component not to update as expected (https://react.dev/reference/react/useRef).
-
-  4 | component C() {
-  5 |   const r = useRef(null);
-> 6 |   const current = !r.current;
-    |                   ^^^^^^^^^^ Cannot access ref value during render
-  7 |   return <div>{current}</div>;
-  8 | }
-  9 |
-
-Error: Cannot access refs during render
-
-React refs are values that are not needed for rendering. Refs should only be accessed outside of render, such as in event handlers or effects. Accessing a ref value (the `current` property) during render can cause your component not to update as expected (https://react.dev/reference/react/useRef).
-
-   5 |   const r = useRef(null);
-   6 |   const current = !r.current;
->  7 |   return <div>{current}</div>;
-     |                ^^^^^^^ Cannot access ref value during render
-   8 | }
-   9 |
-  10 | export const FIXTURE_ENTRYPOINT = {
-
-Error: Cannot access refs during render
-
-React refs are values that are not needed for rendering. Refs should only be accessed outside of render, such as in event handlers or effects. Accessing a ref value (the `current` property) during render can cause your component not to update as expected (https://react.dev/reference/react/useRef).
-
-   5 |   const r = useRef(null);
-   6 |   const current = !r.current;
->  7 |   return <div>{current}</div>;
-     |                ^^^^^^^ Cannot access ref value during render
-   8 | }
-   9 |
-  10 | export const FIXTURE_ENTRYPOINT = {
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-ref-access-render-unary.js

@@ -1,13 +0,0 @@
-//@flow
-import {useRef} from 'react';
-
-component C() {
-  const r = useRef(null);
-  const current = !r.current;
-  return <div>{current}</div>;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: C,
-  params: [{}],
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-ref-initialization-unary-not.expect.md

@@ -1,43 +0,0 @@
-
-## Input
-
-```javascript
-//@flow
-import {useRef} from 'react';
-
-component C() {
-  const r = useRef(null);
-  if (!r.current) {
-    r.current = 1;
-  }
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: C,
-  params: [{}],
-};
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Error: Cannot access refs during render
-
-React refs are values that are not needed for rendering. Refs should only be accessed outside of render, such as in event handlers or effects. Accessing a ref value (the `current` property) during render can cause your component not to update as expected (https://react.dev/reference/react/useRef).
-
-  4 | component C() {
-  5 |   const r = useRef(null);
-> 6 |   if (!r.current) {
-    |        ^^^^^^^^^ Cannot access ref value during render
-  7 |     r.current = 1;
-  8 |   }
-  9 | }
-
-To initialize a ref only once, check that the ref is null with the pattern `if (ref.current == null) { ref.current = ... }`
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-ref-initialization-unary-not.js

@@ -1,14 +0,0 @@
-//@flow
-import {useRef} from 'react';
-
-component C() {
-  const r = useRef(null);
-  if (!r.current) {
-    r.current = 1;
-  }
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: C,
-  params: [{}],
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-setState-in-render-unbound-state.expect.md

@@ -1,41 +0,0 @@
-
-## Input
-
-```javascript
-function Component(props) {
-  // Intentionally don't bind state, this repros a bug where we didn't
-  // infer the type of destructured properties after a hole in the array
-  let [, setState] = useState();
-  setState(1);
-  return props.foo;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: ['TodoAdd'],
-  isComponent: 'TodoAdd',
-};
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Error: Calling setState during render may trigger an infinite loop
-
-Calling setState during render will trigger another render, and can lead to infinite loops. (https://react.dev/reference/react/useState).
-
-error.invalid-setState-in-render-unbound-state.ts:5:2
-  3 |   // infer the type of destructured properties after a hole in the array
-  4 |   let [, setState] = useState();
-> 5 |   setState(1);
-    |   ^^^^^^^^ Found setState() in render
-  6 |   return props.foo;
-  7 | }
-  8 |
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-setState-in-render-unbound-state.js

@@ -1,13 +0,0 @@
-function Component(props) {
-  // Intentionally don't bind state, this repros a bug where we didn't
-  // infer the type of destructured properties after a hole in the array
-  let [, setState] = useState();
-  setState(1);
-  return props.foo;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: ['TodoAdd'],
-  isComponent: 'TodoAdd',
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-uncalled-function-capturing-mutable-values-memoizes-with-captures-values.expect.md

@@ -2,7 +2,7 @@
 ## Input
 
 ```javascript
-// @flow @enableNewMutationAliasingModel @enablePreserveExistingMemoizationGuarantees:false
+// @flow @enableNewMutationAliasingModel
 /**
  * This hook returns a function that when called with an input object,
  * will return the result of mapping that input with the supplied map

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-uncalled-function-capturing-mutable-values-memoizes-with-captures-values.js

@@ -1,4 +1,4 @@
-// @flow @enableNewMutationAliasingModel @enablePreserveExistingMemoizationGuarantees:false
+// @flow @enableNewMutationAliasingModel
 /**
  * This hook returns a function that when called with an input object,
  * will return the result of mapping that input with the supplied map

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-unconditional-set-state-hook-return-in-render.expect.md

@@ -1,55 +0,0 @@
-
-## Input
-
-```javascript
-// @validateNoSetStateInRender @enableTreatSetIdentifiersAsStateSetters
-function Component() {
-  const [state, setState] = useCustomState(0);
-  const aliased = setState;
-
-  setState(1);
-  aliased(2);
-
-  return state;
-}
-
-function useCustomState(init) {
-  return useState(init);
-}
-
-```
-
-
-## Error
-
-```
-Found 2 errors:
-
-Error: Calling setState during render may trigger an infinite loop
-
-Calling setState during render will trigger another render, and can lead to infinite loops. (https://react.dev/reference/react/useState).
-
-error.invalid-unconditional-set-state-hook-return-in-render.ts:6:2
-  4 |   const aliased = setState;
-  5 |
-> 6 |   setState(1);
-    |   ^^^^^^^^ Found setState() in render
-  7 |   aliased(2);
-  8 |
-  9 |   return state;
-
-Error: Calling setState during render may trigger an infinite loop
-
-Calling setState during render will trigger another render, and can lead to infinite loops. (https://react.dev/reference/react/useState).
-
-error.invalid-unconditional-set-state-hook-return-in-render.ts:7:2
-   5 |
-   6 |   setState(1);
->  7 |   aliased(2);
-     |   ^^^^^^^ Found setState() in render
-   8 |
-   9 |   return state;
-  10 | }
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-unconditional-set-state-hook-return-in-render.js

@@ -1,14 +0,0 @@
-// @validateNoSetStateInRender @enableTreatSetIdentifiersAsStateSetters
-function Component() {
-  const [state, setState] = useCustomState(0);
-  const aliased = setState;
-
-  setState(1);
-  aliased(2);
-
-  return state;
-}
-
-function useCustomState(init) {
-  return useState(init);
-}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-unconditional-set-state-prop-in-render.expect.md

@@ -1,50 +0,0 @@
-
-## Input
-
-```javascript
-// @validateNoSetStateInRender @enableTreatSetIdentifiersAsStateSetters
-function Component({setX}) {
-  const aliased = setX;
-
-  setX(1);
-  aliased(2);
-
-  return x;
-}
-
-```
-
-
-## Error
-
-```
-Found 2 errors:
-
-Error: Calling setState during render may trigger an infinite loop
-
-Calling setState during render will trigger another render, and can lead to infinite loops. (https://react.dev/reference/react/useState).
-
-error.invalid-unconditional-set-state-prop-in-render.ts:5:2
-  3 |   const aliased = setX;
-  4 |
-> 5 |   setX(1);
-    |   ^^^^ Found setState() in render
-  6 |   aliased(2);
-  7 |
-  8 |   return x;
-
-Error: Calling setState during render may trigger an infinite loop
-
-Calling setState during render will trigger another render, and can lead to infinite loops. (https://react.dev/reference/react/useState).
-
-error.invalid-unconditional-set-state-prop-in-render.ts:6:2
-  4 |
-  5 |   setX(1);
-> 6 |   aliased(2);
-    |   ^^^^^^^ Found setState() in render
-  7 |
-  8 |   return x;
-  9 | }
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-unconditional-set-state-prop-in-render.js

@@ -1,9 +0,0 @@
-// @validateNoSetStateInRender @enableTreatSetIdentifiersAsStateSetters
-function Component({setX}) {
-  const aliased = setX;
-
-  setX(1);
-  aliased(2);
-
-  return x;
-}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.repro-preserve-memoization-inner-destructured-value-mistaken-as-dependency-later-mutation.expect.md

@@ -2,7 +2,7 @@
 ## Input
 
 ```javascript
-// @validatePreserveExistingMemoizationGuarantees @enablePreserveExistingMemoizationGuarantees:false
+// @validatePreserveExistingMemoizationGuarantees
 
 /**
  * Repro from https://github.com/facebook/react/issues/34262

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.repro-preserve-memoization-inner-destructured-value-mistaken-as-dependency-later-mutation.js

@@ -1,4 +1,4 @@
-// @validatePreserveExistingMemoizationGuarantees @enablePreserveExistingMemoizationGuarantees:false
+// @validatePreserveExistingMemoizationGuarantees
 
 /**
  * Repro from https://github.com/facebook/react/issues/34262