[compiler][patch] Emit unary expressions instead of negative numbers

This is a babel bug + edge case.

Babel compact mode produces invalid JavaScript (i.e. parse error) when given a `NumericLiteral` with a negative value.

See https://codesandbox.io/p/devbox/5d47fr for repro.

As a followup, we could change our test infra parse babel options (e.g. a babel transform options pragma) which could let us track regressions. We may add an "exhaustive" mode to the compiler test runner to test (1) different babel options and (2) commonly used versions.

.codesandbox/ci.json

@@ -1,7 +1,7 @@
 {
   "packages": ["packages/react", "packages/react-dom", "packages/react-server-dom-webpack", "packages/scheduler"],
   "buildCommand": "download-build-in-codesandbox-ci",
-  "node": "20",
+  "node": "18",
   "publishDirectory": {
     "react": "build/oss-experimental/react",
     "react-dom": "build/oss-experimental/react-dom",

.eslintignore

@@ -28,6 +28,3 @@ packages/react-devtools-shared/src/hooks/__tests__/__source__/__untransformed__/
 packages/react-devtools-shell/dist
 packages/react-devtools-timeline/dist
 packages/react-devtools-timeline/static
-
-# Imported third-party Flow types
-flow-typed/

.eslintrc.js

@@ -468,14 +468,13 @@ module.exports = {
       files: ['packages/react-server-dom-webpack/**/*.js'],
       globals: {
         __webpack_chunk_load__: 'readonly',
-        __webpack_get_script_filename__: 'readonly',
         __webpack_require__: 'readonly',
       },
     },
     {
       files: ['packages/react-server-dom-turbopack/**/*.js'],
       globals: {
-        __turbopack_load_by_url__: 'readonly',
+        __turbopack_load__: 'readonly',
         __turbopack_require__: 'readonly',
       },
     },
@@ -497,7 +496,6 @@ module.exports = {
         'packages/react-devtools-shared/src/devtools/views/**/*.js',
         'packages/react-devtools-shared/src/hook.js',
         'packages/react-devtools-shared/src/backend/console.js',
-        'packages/react-devtools-shared/src/backend/fiber/renderer.js',
         'packages/react-devtools-shared/src/backend/shared/DevToolsComponentStackFrame.js',
         'packages/react-devtools-shared/src/frontend/utils/withPermissionsCheck.js',
       ],
@@ -506,7 +504,6 @@ module.exports = {
         __IS_FIREFOX__: 'readonly',
         __IS_EDGE__: 'readonly',
         __IS_NATIVE__: 'readonly',
-        __IS_INTERNAL_MCP_BUILD__: 'readonly',
         __IS_INTERNAL_VERSION__: 'readonly',
         chrome: 'readonly',
       },
@@ -517,14 +514,6 @@ 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'],
@@ -555,10 +544,13 @@ module.exports = {
   },
 
   globals: {
+    $Call: 'readonly',
+    $ElementType: 'readonly',
     $Flow$ModuleRef: 'readonly',
     $FlowFixMe: 'readonly',
     $Keys: 'readonly',
     $NonMaybeType: 'readonly',
+    $PropertyType: 'readonly',
     $ReadOnly: 'readonly',
     $ReadOnlyArray: 'readonly',
     $ArrayBufferView: 'readonly',
@@ -567,13 +559,11 @@ module.exports = {
     ConsoleTask: 'readonly', // TOOD: Figure out what the official name of this will be.
     ReturnType: 'readonly',
     AnimationFrameID: 'readonly',
-    WeakRef: 'readonly',
     // For Flow type annotation. Only `BigInt` is valid at runtime.
     bigint: 'readonly',
     BigInt: 'readonly',
     BigInt64Array: 'readonly',
     BigUint64Array: 'readonly',
-    CacheType: 'readonly',
     Class: 'readonly',
     ClientRect: 'readonly',
     CopyInspectedElementPath: 'readonly',
@@ -585,19 +575,16 @@ module.exports = {
     $AsyncIterator: 'readonly',
     Iterator: 'readonly',
     AsyncIterator: 'readonly',
-    IntervalID: 'readonly',
     IteratorResult: 'readonly',
     JSONValue: 'readonly',
     JSResourceReference: 'readonly',
-    mixin$Animatable: 'readonly',
     MouseEventHandler: 'readonly',
     NavigateEvent: 'readonly',
-    PerformanceMeasureOptions: 'readonly',
     PropagationPhases: 'readonly',
     PropertyDescriptor: 'readonly',
-    PropertyDescriptorMap: 'readonly',
-    Proxy$traps: 'readonly',
+    React$AbstractComponent: 'readonly',
     React$Component: 'readonly',
+    React$ComponentType: 'readonly',
     React$Config: 'readonly',
     React$Context: 'readonly',
     React$Element: 'readonly',
@@ -618,21 +605,19 @@ module.exports = {
     symbol: 'readonly',
     SyntheticEvent: 'readonly',
     SyntheticMouseEvent: 'readonly',
-    SyntheticPointerEvent: 'readonly',
     Thenable: 'readonly',
     TimeoutID: 'readonly',
     WheelEventHandler: 'readonly',
     FinalizationRegistry: 'readonly',
-    Exclude: 'readonly',
     Omit: 'readonly',
     Keyframe: 'readonly',
     PropertyIndexedKeyframes: 'readonly',
     KeyframeAnimationOptions: 'readonly',
     GetAnimationsOptions: 'readonly',
+    Animatable: 'readonly',
     ScrollTimeline: 'readonly',
     EventListenerOptionsOrUseCapture: 'readonly',
     FocusOptions: 'readonly',
-    OptionalEffectTiming: 'readonly',
 
     spyOnDev: 'readonly',
     spyOnDevAndProd: 'readonly',

.github/workflows/compiler_discord_notify.yml

@@ -11,7 +11,6 @@ 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 }}

.github/workflows/compiler_playground.yml

@@ -57,6 +57,8 @@ jobs:
           key: playwright-browsers-v6-${{ runner.arch }}-${{ runner.os }}-${{ steps.playwright_version.outputs.playwright_version }}
       - run: npx playwright install --with-deps chromium
         if: steps.cache_playwright_browsers.outputs.cache-hit != 'true'
+      - run: npx playwright install-deps
+        if: steps.cache_playwright_browsers.outputs.cache-hit == 'true'
       - run: CI=true yarn test
       - run: ls -R test-results
         if: '!cancelled()'

.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

@@ -6,12 +6,6 @@ on:
   pull_request:
     paths-ignore:
       - compiler/**
-  workflow_dispatch:
-    inputs:
-      commit_sha:
-        required: false
-        type: string
-        default: ''
 
 permissions: {}
 
@@ -34,7 +28,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - name: Check cache hit
         uses: actions/cache/restore@v4
         id: node_modules
@@ -75,7 +69,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - name: Check cache hit
         uses: actions/cache/restore@v4
         id: node_modules
@@ -123,7 +117,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/github-script@v7
         id: set-matrix
         with:
@@ -142,7 +136,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -172,7 +166,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -194,7 +188,7 @@ 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:
@@ -204,7 +198,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -260,7 +254,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -286,37 +280,6 @@ jobs:
         if: steps.node_modules.outputs.cache-hit != 'true'
       - run: yarn test ${{ matrix.params }} --ci --shard=${{ matrix.shard }}
 
-  # Hardcoded to improve parallelism
-  test-linter:
-    name: Test eslint-plugin-react-hooks
-    needs: [runtime_compiler_node_modules_cache]
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
-        with:
-          node-version-file: '.nvmrc'
-          cache: yarn
-          cache-dependency-path:  |
-            yarn.lock
-            compiler/yarn.lock
-      - name: Restore cached node_modules
-        uses: actions/cache@v4
-        id: node_modules
-        with:
-          path: |
-            **/node_modules
-          key: runtime-and-compiler-node_modules-v6-${{ runner.arch }}-${{ runner.os }}-${{ hashFiles('yarn.lock', 'compiler/yarn.lock') }}
-      - name: Install runtime dependencies
-        run: yarn install --frozen-lockfile
-        if: steps.node_modules.outputs.cache-hit != 'true'
-      - name: Install compiler dependencies
-        run: yarn install --frozen-lockfile
-        working-directory: compiler
-        if: steps.node_modules.outputs.cache-hit != 'true'
-      - run: ./scripts/react-compiler/build-compiler.sh && ./scripts/react-compiler/link-compiler.sh
-      - run: yarn workspace eslint-plugin-react-hooks test
-
   # ----- BUILD -----
   build_and_lint:
     name: yarn build and lint
@@ -331,7 +294,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -426,7 +389,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -471,7 +434,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -499,7 +462,7 @@ jobs:
           merge-multiple: true
       - name: Display structure of build
         run: ls -R build
-      - run: echo ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }} >> build/COMMIT_SHA
+      - run: echo ${{ github.event.pull_request.head.sha || github.sha }} >> build/COMMIT_SHA
       - name: Scrape warning messages
         run: |
           mkdir -p ./build/__test_utils__
@@ -536,7 +499,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -567,7 +530,7 @@ 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
@@ -576,7 +539,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -613,7 +576,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -654,7 +617,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -728,7 +691,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -766,11 +729,6 @@ jobs:
           name: react-devtools-${{ 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 +739,7 @@ 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
@@ -790,7 +748,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -816,27 +774,12 @@ jobs:
           pattern: _build_*
           path: build
           merge-multiple: true
-      - name: Check Playwright version
-        id: playwright_version
-        run: echo "playwright_version=$(npm ls @playwright/test | grep @playwright | sed 's/.*@//' | head -1)" >> "$GITHUB_OUTPUT"
-      - name: Cache Playwright Browsers for version ${{ steps.playwright_version.outputs.playwright_version }}
-        id: cache_playwright_browsers
-        uses: actions/cache@v4
-        with:
-          path: ~/.cache/ms-playwright
-          key: playwright-browsers-v6-${{ runner.arch }}-${{ runner.os }}-${{ steps.playwright_version.outputs.playwright_version }}
-      - name: Playwright install deps
-        if: steps.cache_playwright_browsers.outputs.cache-hit != 'true'
-        run: npx playwright install --with-deps chromium
+      - run: |
+          npx playwright install
+          sudo npx playwright install-deps
       - 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:
@@ -850,7 +793,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          ref: ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
       - uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
@@ -899,7 +842,7 @@ jobs:
           node ./scripts/print-warnings/print-warnings.js > build/__test_utils__/ReactAllWarnings.js
       - name: Display structure of build for PR
         run: ls -R build
-      - run: echo ${{ github.event.inputs.commit_sha != '' && github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }} >> build/COMMIT_SHA
+      - run: echo ${{ github.event.pull_request.head.sha || github.sha }} >> build/COMMIT_SHA
       - run: node ./scripts/tasks/danger
       - name: Archive sizebot results
         uses: actions/upload-artifact@v4

.github/workflows/runtime_discord_notify.yml

@@ -4,16 +4,13 @@ on:
   pull_request_target:
     types: [opened, ready_for_review]
     paths-ignore:
-      - packages/react-devtools**
       - compiler/**
       - .github/workflows/compiler_**.yml
-      - .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 }}

.github/workflows/runtime_prereleases.yml

@@ -17,17 +17,6 @@ on:
         description: 'Whether to notify the team on Discord when the release fails. Useful if this workflow is called from an automation.'
         required: false
         type: boolean
-      only_packages:
-        description: Packages to publish (space separated)
-        type: string
-      skip_packages:
-        description: Packages to NOT publish (space separated)
-        type: string
-      dry:
-        required: true
-        description: Dry run instead of publish?
-        type: boolean
-        default: true
     secrets:
       DISCORD_WEBHOOK_URL:
         description: 'Discord webhook URL to notify on failure. Only required if enableFailureNotification is true.'
@@ -72,39 +61,15 @@ jobs:
         if: steps.node_modules.outputs.cache-hit != 'true'
       - run: yarn --cwd scripts/release install --frozen-lockfile
         if: steps.node_modules.outputs.cache-hit != 'true'
-      - run: cp ./scripts/release/ci-npmrc ~/.npmrc
       - run: |
           GH_TOKEN=${{ secrets.GH_TOKEN }} scripts/release/prepare-release-from-ci.js --skipTests -r ${{ inputs.release_channel }} --commit=${{ inputs.commit_sha }}
-      - name: Check prepared files
-        run: ls -R build/node_modules
-      - if: '${{ inputs.only_packages }}'
-        name: 'Publish ${{ inputs.only_packages }}'
-        run: |
-          scripts/release/publish.js \
-            --ci \
-            --tags=${{ inputs.dist_tag }} \
-            --onlyPackages=${{ inputs.only_packages }} ${{ (inputs.dry && '') || '\'}}
-            ${{ inputs.dry && '--dry' || '' }}
-      - if: '${{ inputs.skip_packages }}'
-        name: 'Publish all packages EXCEPT ${{ inputs.skip_packages }}'
-        run: |
-          scripts/release/publish.js \
-            --ci \
-            --tags=${{ inputs.dist_tag }} \
-            --skipPackages=${{ inputs.skip_packages }} ${{ (inputs.dry && '') || '\'}}
-            ${{ inputs.dry && '--dry' || '' }}
-      - if: '${{ !inputs.skip_packages && !inputs.only_packages }}'
-        name: 'Publish all packages'
-        run: |
-          scripts/release/publish.js \
-            --ci \
-            --tags=${{ inputs.dist_tag }} ${{ (inputs.dry && '') || '\'}}
-            ${{ inputs.dry && '--dry' || '' }}
+          cp ./scripts/release/ci-npmrc ~/.npmrc
+          scripts/release/publish.js --ci --tags ${{ inputs.dist_tag }}
       - name: Notify Discord on failure
         if: failure() && inputs.enableFailureNotification == true
         uses: tsickert/discord-webhook@86dc739f3f165f16dadc5666051c367efa1692f4
         with:
           webhook-url: ${{ secrets.DISCORD_WEBHOOK_URL }}
           embed-author-name: "GitHub Actions"
-          embed-title: '[Runtime] Publish of ${{ inputs.release_channel }}@${{ inputs.dist_tag}} release failed'
+          embed-title: 'Publish of $${{ inputs.release_channel }} release failed'
           embed-url: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}/attempts/${{ github.run_attempt }}

.github/workflows/runtime_prereleases_manual.yml

@@ -5,25 +5,6 @@ on:
     inputs:
       prerelease_commit_sha:
         required: true
-      only_packages:
-        description: Packages to publish (space separated)
-        type: string
-      skip_packages:
-        description: Packages to NOT publish (space separated)
-        type: string
-      dry:
-        required: true
-        description: Dry run instead of publish?
-        type: boolean
-        default: true
-      experimental_only:
-        type: boolean
-        description: Only publish to the experimental tag
-        default: false
-      force_notify:
-        description: Force a Discord notification?
-        type: boolean
-        default: false
 
 permissions: {}
 
@@ -31,26 +12,8 @@ env:
   TZ: /usr/share/zoneinfo/America/Los_Angeles
 
 jobs:
-  notify:
-    if: ${{ inputs.force_notify || inputs.dry == false || inputs.dry == 'false' }}
-    runs-on: ubuntu-latest
-    steps:
-      - name: Discord Webhook Action
-        uses: tsickert/discord-webhook@86dc739f3f165f16dadc5666051c367efa1692f4
-        with:
-          webhook-url: ${{ secrets.DISCORD_WEBHOOK_URL }}
-          embed-author-name: ${{ github.event.sender.login }}
-          embed-author-url: ${{ github.event.sender.html_url }}
-          embed-author-icon-url: ${{ github.event.sender.avatar_url }}
-          embed-title: "⚠️ Publishing ${{ inputs.experimental_only && 'EXPERIMENTAL' || 'CANARY & EXPERIMENTAL' }} release ${{ (inputs.dry && ' (dry run)') || '' }}"
-          embed-description: |
-            ```json
-            ${{ toJson(inputs) }}
-            ```
-          embed-url: https://github.com/facebook/react/actions/runs/${{ github.run_id }}
 
   publish_prerelease_canary:
-    if: ${{ !inputs.experimental_only }}
     name: Publish to Canary channel
     uses: facebook/react/.github/workflows/runtime_prereleases.yml@main
     permissions:
@@ -70,9 +33,6 @@ jobs:
       # downstream consumers might still expect that tag. We can remove this
       # after some time has elapsed and the change has been communicated.
       dist_tag: canary,next
-      only_packages: ${{ inputs.only_packages }}
-      skip_packages: ${{ inputs.skip_packages }}
-      dry: ${{ inputs.dry }}
     secrets:
       NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
@@ -88,15 +48,10 @@ jobs:
     # different versions of the same package, even if they use different
     # dist tags.
     needs: publish_prerelease_canary
-    # Ensures the job runs even if canary is skipped
-    if: always()
     with:
       commit_sha: ${{ inputs.prerelease_commit_sha }}
       release_channel: experimental
       dist_tag: experimental
-      only_packages: ${{ inputs.only_packages }}
-      skip_packages: ${{ inputs.skip_packages }}
-      dry: ${{ inputs.dry }}
     secrets:
       NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/runtime_prereleases_nightly.yml

@@ -22,7 +22,6 @@ jobs:
       release_channel: stable
       dist_tag: canary,next
       enableFailureNotification: true
-      dry: false
     secrets:
       DISCORD_WEBHOOK_URL: ${{ secrets.DISCORD_WEBHOOK_URL }}
       NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
@@ -44,7 +43,6 @@ jobs:
       release_channel: experimental
       dist_tag: experimental
       enableFailureNotification: true
-      dry: false
     secrets:
       DISCORD_WEBHOOK_URL: ${{ secrets.DISCORD_WEBHOOK_URL }}
       NPM_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/runtime_releases_from_npm_manual.yml

@@ -110,7 +110,7 @@ jobs:
             --tags=${{ inputs.tags }} \
             --publishVersion=${{ inputs.version_to_publish }} \
             --onlyPackages=${{ inputs.only_packages }} ${{ (inputs.dry && '') || '\'}}
-            ${{ inputs.dry && '--dry' || '' }}
+            ${{ inputs.dry && '--dry'}}
       - if: '${{ inputs.skip_packages }}'
         name: 'Publish all packages EXCEPT ${{ inputs.skip_packages }}'
         run: |
@@ -119,7 +119,7 @@ jobs:
             --tags=${{ inputs.tags }} \
             --publishVersion=${{ inputs.version_to_publish }} \
             --skipPackages=${{ inputs.skip_packages }} ${{ (inputs.dry && '') || '\'}}
-            ${{ inputs.dry && '--dry' || '' }}
+            ${{ inputs.dry && '--dry'}}
       - name: Archive released package for debugging
         uses: actions/upload-artifact@v4
         with:

.github/workflows/shared_close_direct_sync_branch_prs.yml

@@ -18,7 +18,6 @@ jobs:
     permissions:
       # Used to create a review and close PRs
       pull-requests: write
-      contents: write
     steps:
       - name: Close PR
         uses: actions/github-script@v7

.github/workflows/shared_stale.yml

@@ -6,10 +6,7 @@ on:
     - cron: '0 * * * *'
   workflow_dispatch:
 
-permissions:
-  # https://github.com/actions/stale/tree/v9/?tab=readme-ov-file#recommended-permissions
-  issues: write
-  pull-requests: write
+permissions: {}
 
 env:
   TZ: /usr/share/zoneinfo/America/Los_Angeles

.gitignore

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

.prettierrc.js

@@ -3,12 +3,13 @@
 const {esNextPaths} = require('./scripts/shared/pathsByLanguageVersion');
 
 module.exports = {
+  plugins: ['prettier-plugin-hermes-parser'],
   bracketSpacing: false,
   singleQuote: true,
   bracketSameLine: true,
   trailingComma: 'es5',
   printWidth: 80,
-  parser: 'flow',
+  parser: 'hermes',
   arrowParens: 'avoid',
   overrides: [
     {

CHANGELOG.md

@@ -1,81 +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
-* Fixed Owner Stacks to work with ES2015 function.name semantics ([#33680](https://github.com/facebook/react/pull/33680) by @hoxyq)
-
 ## 19.1.0 (March 28, 2025)
 
 ### Owner Stack
@@ -97,11 +19,11 @@ An Owner Stack is a string representing the components that are directly respons
 * Updated `useId` to use valid CSS selectors, changing format from `:r123:` to `«r123»`. [#32001](https://github.com/facebook/react/pull/32001)
 * Added a dev-only warning for null/undefined created in useEffect, useInsertionEffect, and useLayoutEffect. [#32355](https://github.com/facebook/react/pull/32355)
 * Fixed a bug where dev-only methods were exported in production builds. React.act is no longer available in production builds. [#32200](https://github.com/facebook/react/pull/32200)
-* Improved consistency across prod and dev to improve compatibility with Google Closure Compiler and bindings [#31808](https://github.com/facebook/react/pull/31808)
+* Improved consistency across prod and dev to improve compatibility with Google Closure Complier and bindings [#31808](https://github.com/facebook/react/pull/31808)
 * Improve passive effect scheduling for consistent task yielding. [#31785](https://github.com/facebook/react/pull/31785)
 * Fixed asserts in React Native when passChildrenWhenCloningPersistedNodes is enabled for OffscreenComponent rendering. [#32528](https://github.com/facebook/react/pull/32528)
 * Fixed component name resolution for Portal [#32640](https://github.com/facebook/react/pull/32640)
-* Added support for beforetoggle and toggle events on the dialog element. [#32479](https://github.com/facebook/react/pull/32479)
+* Added support for beforetoggle and toggle events on the dialog element. #32479 [#32479](https://github.com/facebook/react/pull/32479)
 
 ### React DOM
 * Fixed double warning when the `href` attribute is an empty string [#31783](https://github.com/facebook/react/pull/31783)

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

babel.config-ts.js

@@ -8,7 +8,6 @@ module.exports = {
     '@babel/plugin-syntax-jsx',
     '@babel/plugin-transform-flow-strip-types',
     ['@babel/plugin-transform-class-properties', {loose: true}],
-    ['@babel/plugin-transform-private-methods', {loose: true}],
     '@babel/plugin-transform-classes',
   ],
   presets: [

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

@@ -1,215 +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 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 {Resizable} from 're-resizable';
-import {useStore, useStoreDispatch} from '../StoreContext';
-import {monacoConfigOptions} from './monacoOptions';
-import {IconChevron} from '../Icons/IconChevron';
-import {CONFIG_PANEL_TRANSITION} from '../../lib/transitionTypes';
-
-// @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 {
-  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 handleChange: (value: string | undefined) => void = (
-    value: string | undefined,
-  ) => {
-    if (value === undefined) return;
-
-    if (debounceTimerRef.current) {
-      clearTimeout(debounceTimerRef.current);
-    }
-
-    debounceTimerRef.current = setTimeout(() => {
-      dispatchStore({
-        type: 'updateConfig',
-        payload: {
-          config: value,
-        },
-      });
-    }, 500); // 500ms debounce delay
-  };
-
-  const handleMount: (
-    _: editor.IStandaloneCodeEditor,
-    monaco: Monaco,
-  ) => void = (_, monaco) => {
-    // Add the babel-plugin-react-compiler type definitions to Monaco
-    monaco.languages.typescript.typescriptDefaults.addExtraLib(
-      //@ts-expect-error - compilerTypeDefs is a string
-      compilerTypeDefs,
-      'file:///node_modules/babel-plugin-react-compiler/dist/index.d.ts',
-    );
-    monaco.languages.typescript.typescriptDefaults.setCompilerOptions({
-      target: monaco.languages.typescript.ScriptTarget.Latest,
-      allowNonTsExtensions: true,
-      moduleResolution: monaco.languages.typescript.ModuleResolutionKind.NodeJs,
-      module: monaco.languages.typescript.ModuleKind.ESNext,
-      noEmit: true,
-      strict: false,
-      esModuleInterop: true,
-      allowSyntheticDefaultImports: true,
-      jsx: monaco.languages.typescript.JsxEmit.React,
-    });
-  };
-
-  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">
-              <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,
-                }}
-              />
-            </div>
-          </div>
-        </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

@@ -5,63 +5,289 @@
  * 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,
+  ErrorSeverity,
+  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 ConfigEditor from './ConfigEditor';
+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 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';
+
+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): [CompilerOutput, 'flow' | 'typescript'] {
+  const results = new Map<string, Array<PrintedCompilerPipelineValue>>();
+  const error = new CompilerError();
+  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',
+    });
+    const opts: PluginOptions = parsePluginOptions({
+      ...parsedOptions,
+      environment: {
+        ...parsedOptions.environment,
+        customHooks: new Map([...COMMON_HOOKS]),
+      },
+      logger: {
+        debugLogIRs: logIR,
+        logEvent: () => {},
+      },
+    });
+    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.details.push(...err.details);
+    } else {
+      /**
+       * Handle unexpected failures by logging (to get a stack trace)
+       * and reporting
+       */
+      console.error(err);
+      error.details.push(
+        new CompilerErrorDetail({
+          severity: ErrorSeverity.Invariant,
+          reason: `Unexpected failure when transforming input! ${err}`,
+          loc: null,
+          suggestions: null,
+        }),
+      );
+    }
+  }
+  if (error.hasErrors()) {
+    return [{kind: 'err', results, error: error}, language];
+  }
+  return [{kind: 'ok', results, transformOutput}, 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),
+    [deferredStore.source],
   );
-  const [linterOutput] = useMemo(
-    () => compile(deferredStore.source, 'linter', deferredStore.config),
-    [deferredStore.source, deferredStore.config],
-  );
-  const [formattedAppliedConfig, setFormattedAppliedConfig] = useState('');
 
-  let mergedOutput: CompilerOutput;
-  let errors: Array<CompilerErrorDetail | CompilerDiagnostic>;
-  if (compilerOutput.kind === 'ok') {
-    errors = linterOutput.kind === 'ok' ? [] : linterOutput.error.details;
-    mergedOutput = {
-      ...compilerOutput,
-      errors,
-    };
-  } else {
-    mergedOutput = compilerOutput;
-    errors = compilerOutput.error.details;
-  }
-
-  if (appliedOptions) {
-    const formatted = prettyFormat(appliedOptions, {
-      printFunctionName: false,
-      printBasicPrototype: false,
-    });
-    if (formatted !== formattedAppliedConfig) {
-      setFormattedAppliedConfig(formatted);
+  useMountEffect(() => {
+    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},
+    });
+  });
 
   return (
     <>
-      <div className="relative flex top-14">
-        <div className="flex-shrink-0">
-          <ConfigEditor formattedAppliedConfig={formattedAppliedConfig} />
+      <div className="relative flex basis top-14">
+        <div className={clsx('relative sm:basis-1/4')}>
+          <Input
+            language={language}
+            errors={
+              compilerOutput.kind === 'err' ? compilerOutput.error.details : []
+            }
+          />
         </div>
-        <div className="flex flex-1 min-w-0">
-          <Input language={language} errors={errors} />
-          <Output store={deferredStore} compilerOutput={mergedOutput} />
+        <div className={clsx('flex sm:flex flex-wrap')}>
+          <Output store={deferredStore} compilerOutput={compilerOutput} />
         </div>
       </div>
     </>

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

@@ -6,31 +6,22 @@
  */
 
 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';
 
 loader.config({monaco});
 
 type Props = {
-  errors: Array<CompilerErrorDetail | CompilerDiagnostic>;
+  errors: Array<CompilerErrorDetail>;
   language: 'flow' | 'typescript';
 };
 
@@ -45,13 +36,13 @@ export default function Input({errors, language}: Props): JSX.Element {
     const uri = monaco.Uri.parse(`file:///index.js`);
     const model = monaco.editor.getModel(uri);
     invariant(model, 'Model must exist for the selected input file.');
-    renderReactCompilerMarkers({
-      monaco,
-      model,
-      details: errors,
-      source: store.source,
-    });
-  }, [monaco, errors, store.source]);
+    renderReactCompilerMarkers({monaco, model, details: errors});
+    /**
+     * 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]);
 
   useEffect(() => {
     /**
@@ -83,11 +74,11 @@ export default function Input({errors, language}: Props): JSX.Element {
     });
   }, [monaco, language]);
 
-  const handleChange: (value: string | undefined) => void = async value => {
+  const handleChange: (value: string | undefined) => void = value => {
     if (!value) return;
 
     dispatchStore({
-      type: 'updateSource',
+      type: 'updateFile',
       payload: {
         source: value,
       },
@@ -139,42 +130,30 @@ 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

@@ -11,46 +11,19 @@ import {
   InformationCircleIcon,
 } from '@heroicons/react/outline';
 import MonacoEditor, {DiffEditor} from '@monaco-editor/react';
-import {
-  CompilerErrorDetail,
-  CompilerDiagnostic,
-  type CompilerError,
-} from 'babel-plugin-react-compiler';
+import {type CompilerError} from 'babel-plugin-react-compiler';
 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';
@@ -71,7 +44,6 @@ export type CompilerOutput =
       kind: 'ok';
       transformOutput: CompilerTransformOutput;
       results: Map<string, Array<PrintedCompilerPipelineValue>>;
-      errors: Array<CompilerErrorDetail | CompilerDiagnostic>;
     }
   | {
       kind: 'err';
@@ -87,16 +59,12 @@ type Props = {
 async function tabify(
   source: string,
   compilerOutput: CompilerOutput,
-  showInternals: boolean,
 ): Promise<Map<string, ReactNode>> {
   const tabs = new Map<string, React.ReactNode>();
   const reorderedTabs = new Map<string, React.ReactNode>();
   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)) {
-      continue;
-    }
     for (const result of results) {
       switch (result.kind) {
         case 'hir': {
@@ -155,36 +123,10 @@ async function tabify(
       parser: transformOutput.language === 'flow' ? 'babel-flow' : 'babel-ts',
       plugins: [parserBabel, prettierPluginEstree],
     });
-
-    let output: string;
-    let language: string;
-    if (compilerOutput.errors.length === 0) {
-      output = code;
-      language = 'javascript';
-    } else {
-      language = 'markdown';
-      output = `
-# Summary
-
-React Compiler compiled this function successfully, but there are lint errors that indicate potential issues with the original code.
-
-## ${compilerOutput.errors.length} Lint Errors
-
-${compilerOutput.errors.map(e => e.printErrorMessage(source, {eslint: false})).join('\n\n')}
-
-## Output
-
-\`\`\`js
-${code}
-\`\`\`
-`.trim();
-    }
-
     reorderedTabs.set(
-      'Output',
+      'JS',
       <TextTabContent
-        output={output}
-        language={language}
+        output={code}
         diff={null}
         showInfoPanel={false}></TextTabContent>,
     );
@@ -200,18 +142,6 @@ ${code}
         </>,
       );
     }
-  } else if (compilerOutput.kind === 'err') {
-    const errors = compilerOutput.error.printErrorMessage(source, {
-      eslint: false,
-    });
-    reorderedTabs.set(
-      'Output',
-      <TextTabContent
-        output={errors}
-        language="markdown"
-        diff={null}
-        showInfoPanel={false}></TextTabContent>,
-    );
   }
   tabs.forEach((tab, name) => {
     reorderedTabs.set(name, tab);
@@ -219,25 +149,6 @@ ${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));
 }
@@ -251,40 +162,17 @@ 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>
+  const [tabsOpen, setTabsOpen] = useState<Set<string>>(() => new Set(['JS']));
+  const [tabs, setTabs] = useState<Map<string, React.ReactNode>>(
+    () => new Map(),
   );
-}
+  useEffect(() => {
+    tabify(store.source, compilerOutput).then(tabs => {
+      setTabs(tabs);
+    });
+  }, [store.source, compilerOutput]);
 
-function OutputContent({store, compilerOutput}: Props): JSX.Element {
-  const [tabsOpen, setTabsOpen] = useState<Set<string>>(
-    () => new Set(['Output']),
-  );
-  const [activeTab, setActiveTab] = useState<string>('Output');
-
-  /*
-   * Update the active tab back to the output or errors tab when the compilation state
-   * changes between success/failure.
-   */
-  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');
-      });
-    }
-  }
-
-  const changedPasses: Set<string> = new Set(['Output', 'HIR']); // Initial and final passes should always be bold
+  const changedPasses: Set<string> = new Set(['JS', 'HIR']); // Initial and final passes should always be bold
   let lastResult: string = '';
   for (const [passName, results] of compilerOutput.results) {
     for (const result of results) {
@@ -298,40 +186,31 @@ 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
-        defaultTab={store.showInternals ? 'HIR' : 'Output'}
+    <>
+      <TabbedWindow
+        defaultTab="HIR"
         setTabsOpen={setTabsOpen}
         tabsOpen={tabsOpen}
         tabs={tabs}
         changedPasses={changedPasses}
       />
-    </ViewTransition>
+      {compilerOutput.kind === 'err' ? (
+        <div
+          className="flex flex-wrap absolute bottom-0 bg-white grow border-y border-grey-200 transition-all ease-in"
+          style={{width: 'calc(100vw - 650px)'}}>
+          <div className="w-full p-4 basis-full border-b">
+            <h2>COMPILER ERRORS</h2>
+          </div>
+          <pre
+            className="p-4 basis-full text-red-600 overflow-y-scroll whitespace-pre-wrap"
+            style={{width: 'calc(100vw - 650px)', height: '150px'}}>
+            <code>{compilerOutput.error.toString()}</code>
+          </pre>
+        </div>
+      ) : null}
+    </>
   );
 }
 
@@ -339,12 +218,10 @@ function TextTabContent({
   output,
   diff,
   showInfoPanel,
-  language,
 }: {
   output: string;
   diff: string | null;
   showInfoPanel: boolean;
-  language: string;
 }): JSX.Element {
   const [diffMode, setDiffMode] = useState(false);
   return (
@@ -383,29 +260,20 @@ 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'}
+          defaultLanguage="javascript"
           value={output}
-          loading={''}
-          className="monaco-editor-output"
           options={{
             ...monacoOptions,
             readOnly: true,

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

@@ -28,18 +28,5 @@ 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,
+  wrappingIndent: 'deepIndent',
 };

compiler/apps/playground/components/Header.tsx

@@ -10,20 +10,14 @@ 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';
+import {useStoreDispatch} from './StoreContext';
 
 export default function Header(): JSX.Element {
   const [showCheck, setShowCheck] = useState(false);
-  const store = useStore();
   const dispatchStore = useStoreDispatch();
   const {enqueueSnackbar, closeSnackbar} = useSnackbar();
 
@@ -62,32 +56,6 @@ export default function Header(): JSX.Element {
         <p className="hidden select-none sm:block">React Compiler Playground</p>
       </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">
-            <input
-              type="checkbox"
-              checked={store.showInternals}
-              onChange={() =>
-                startTransition(() => {
-                  addTransitionType(TOGGLE_INTERNALS_TRANSITION);
-                  dispatchStore({type: 'toggleInternals'});
-                })
-              }
-              className="absolute opacity-0 cursor-pointer h-full w-full m-0"
-            />
-            <span
-              className={clsx(
-                'absolute inset-0 rounded-full cursor-pointer transition-all duration-250',
-                "before:content-[''] before:absolute before:w-4 before:h-4 before:left-0.5 before:bottom-0.5",
-                '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-gray-300',
-              )}></span>
-          </label>
-          <span className="text-secondary">Show Internals</span>
-        </div>
         <button
           title="Reset Playground"
           aria-label="Reset Playground"

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>
   );
@@ -71,19 +53,10 @@ type ReducerAction =
       };
     }
   | {
-      type: 'updateSource';
+      type: 'updateFile';
       payload: {
         source: string;
       };
-    }
-  | {
-      type: 'updateConfig';
-      payload: {
-        config: string;
-      };
-    }
-  | {
-      type: 'toggleInternals';
     };
 
 function storeReducer(store: Store, action: ReducerAction): Store {
@@ -92,28 +65,13 @@ 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} = action.payload;
       const newStore = {
         ...store,
         source,
       };
       return newStore;
     }
-    case 'updateConfig': {
-      const config = action.payload.config;
-      const newStore = {
-        ...store,
-        config,
-      };
-      return newStore;
-    }
-    case 'toggleInternals': {
-      const newStore = {
-        ...store,
-        showInternals: !store.showInternals,
-      };
-      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/defaultStore.ts

@@ -13,21 +13,10 @@ export default function MyApp() {
 }
 `;
 
-export const defaultConfig = `\
-import type { PluginOptions } from 'babel-plugin-react-compiler/dist';
-
-({
-  //compilationMode: "all"
-} satisfies PluginOptions);`;
-
 export const defaultStore: Store = {
   source: index,
-  config: defaultConfig,
-  showInternals: false,
 };
 
 export const emptyStore: Store = {
   source: '',
-  config: '',
-  showInternals: false,
 };

compiler/apps/playground/lib/reactCompilerMonacoDiagnostics.ts

@@ -6,11 +6,7 @@
  */
 
 import {Monaco} from '@monaco-editor/react';
-import {
-  CompilerDiagnostic,
-  CompilerErrorDetail,
-  ErrorSeverity,
-} from 'babel-plugin-react-compiler';
+import {CompilerErrorDetail, ErrorSeverity} from 'babel-plugin-react-compiler';
 import {MarkerSeverity, type editor} from 'monaco-editor';
 
 function mapReactCompilerSeverityToMonaco(
@@ -26,46 +22,38 @@ function mapReactCompilerSeverityToMonaco(
 }
 
 function mapReactCompilerDiagnosticToMonacoMarker(
-  detail: CompilerErrorDetail | CompilerDiagnostic,
+  detail: CompilerErrorDetail,
   monaco: Monaco,
-  source: string,
 ): editor.IMarkerData | null {
-  const loc = detail.primaryLocation();
-  if (loc == null || typeof loc === 'symbol') {
+  if (detail.loc == null || typeof detail.loc === 'symbol') {
     return null;
   }
   const severity = mapReactCompilerSeverityToMonaco(detail.severity, monaco);
-  let message = detail.printErrorMessage(source, {eslint: true});
+  let message = detail.printErrorMessage();
   return {
     severity,
     message,
-    startLineNumber: loc.start.line,
-    startColumn: loc.start.column + 1,
-    endLineNumber: loc.end.line,
-    endColumn: loc.end.column + 1,
+    startLineNumber: detail.loc.start.line,
+    startColumn: detail.loc.start.column + 1,
+    endLineNumber: detail.loc.end.line,
+    endColumn: detail.loc.end.column + 1,
   };
 }
 
 type ReactCompilerMarkerConfig = {
   monaco: Monaco;
   model: editor.ITextModel;
-  details: Array<CompilerErrorDetail | CompilerDiagnostic>;
-  source: string;
+  details: Array<CompilerErrorDetail>;
 };
 let decorations: Array<string> = [];
 export function renderReactCompilerMarkers({
   monaco,
   model,
   details,
-  source,
 }: ReactCompilerMarkerConfig): void {
   const markers: Array<editor.IMarkerData> = [];
   for (const detail of details) {
-    const marker = mapReactCompilerDiagnosticToMonacoMarker(
-      detail,
-      monaco,
-      source,
-    );
+    const marker = mapReactCompilerDiagnosticToMonacoMarker(detail, monaco);
     if (marker == null) {
       continue;
     }

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

@@ -10,20 +10,18 @@ import {
   compressToEncodedURIComponent,
   decompressFromEncodedURIComponent,
 } from 'lz-string';
-import {defaultStore, defaultConfig} from '../defaultStore';
+import {defaultStore} from '../defaultStore';
 
 /**
  * Global Store for Playground
  */
 export interface Store {
   source: string;
-  config: string;
-  showInternals: boolean;
 }
 export function encodeStore(store: Store): string {
   return compressToEncodedURIComponent(JSON.stringify(store));
 }
-export function decodeStore(hash: string): any {
+export function decodeStore(hash: string): Store {
   return JSON.parse(decompressFromEncodedURIComponent(hash));
 }
 
@@ -64,14 +62,8 @@ export function initStoreFromUrlOrLocalStorage(): Store {
    */
   if (!encodedSource) return defaultStore;
 
-  const raw: any = decodeStore(encodedSource);
+  const raw = decodeStore(encodedSource);
 
   invariant(isValidStore(raw), 'Invalid Store');
-
-  // Make sure all properties are populated
-  return {
-    source: raw.source,
-    config: 'config' in raw && raw['config'] ? raw.config : defaultConfig,
-    showInternals: 'showInternals' in raw ? raw.showInternals : false,
-  };
+  return raw;
 }

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 +1,5 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.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

@@ -32,33 +32,28 @@
     "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": "^15.2.0-canary.64",
     "notistack": "^3.0.0-alpha.7",
     "prettier": "^3.3.3",
     "pretty-format": "^29.3.1",
     "re-resizable": "^6.9.16",
-    "react": "19.1.1",
-    "react-dom": "19.1.1"
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0"
   },
   "devDependencies": {
     "@types/node": "18.11.9",
-    "@types/react": "19.1.13",
-    "@types/react-dom": "19.1.9",
+    "@types/react": "^19.0.0",
+    "@types/react-dom": "^19.0.0",
     "autoprefixer": "^10.4.13",
     "clsx": "^1.2.1",
     "concurrently": "^7.4.0",
     "eslint": "^8.28.0",
-    "eslint-config-next": "15.5.2",
+    "eslint-config-next": "^15.0.1",
     "monaco-editor-webpack-plugin": "^7.1.0",
     "postcss": "^8.4.31",
     "tailwindcss": "^3.2.4",
     "wait-on": "^7.2.0"
-  },
-  "resolutions": {
-    "@types/react": "19.1.12",
-    "@types/react-dom": "19.1.9"
   }
 }

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/scripts/link-compiler.sh

@@ -8,8 +8,8 @@ set -eo pipefail
 
 HERE=$(pwd)
 
-cd ../../packages/react-compiler-runtime && yarn --silent link && cd "$HERE"
-cd ../../packages/babel-plugin-react-compiler && yarn --silent link && cd "$HERE"
+cd ../../packages/react-compiler-runtime && yarn --silent link && cd $HERE
+cd ../../packages/babel-plugin-react-compiler && yarn --silent link && cd $HERE
 
 yarn --silent link babel-plugin-react-compiler
 yarn --silent link react-compiler-runtime

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/package.json

@@ -19,8 +19,7 @@
     "test": "yarn workspaces run test",
     "snap": "yarn workspace babel-plugin-react-compiler run snap",
     "snap:build": "yarn workspace snap run build",
-    "npm:publish": "node scripts/release/publish",
-    "eslint-docs": "yarn workspace babel-plugin-react-compiler build && node scripts/build-eslint-docs.js"
+    "npm:publish": "node scripts/release/publish"
   },
   "dependencies": {
     "fs-extra": "^4.0.2",

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/BabelPlugin.ts

@@ -12,7 +12,6 @@ import {
   pipelineUsesReanimatedPlugin,
 } from '../Entrypoint/Reanimated';
 import validateNoUntransformedReferences from '../Entrypoint/ValidateNoUntransformedReferences';
-import {CompilerError} from '..';
 
 const ENABLE_REACT_COMPILER_TIMINGS =
   process.env['ENABLE_REACT_COMPILER_TIMINGS'] === '1';
@@ -35,58 +34,51 @@ export default function BabelPluginReactCompiler(
        */
       Program: {
         enter(prog, pass): void {
-          try {
-            const filename = pass.filename ?? 'unknown';
-            if (ENABLE_REACT_COMPILER_TIMINGS === true) {
-              performance.mark(`${filename}:start`, {
-                detail: 'BabelPlugin:Program:start',
-              });
-            }
-            let opts = parsePluginOptions(pass.opts);
-            const isDev =
-              (typeof __DEV__ !== 'undefined' && __DEV__ === true) ||
-              process.env['NODE_ENV'] === 'development';
-            if (
-              opts.enableReanimatedCheck === true &&
-              pipelineUsesReanimatedPlugin(pass.file.opts.plugins)
-            ) {
-              opts = injectReanimatedFlag(opts);
-            }
-            if (
-              opts.environment.enableResetCacheOnSourceFileChanges !== false &&
-              isDev
-            ) {
-              opts = {
-                ...opts,
-                environment: {
-                  ...opts.environment,
-                  enableResetCacheOnSourceFileChanges: true,
-                },
-              };
-            }
-            const result = compileProgram(prog, {
-              opts,
-              filename: pass.filename ?? null,
-              comments: pass.file.ast.comments ?? [],
-              code: pass.file.code,
+          const filename = pass.filename ?? 'unknown';
+          if (ENABLE_REACT_COMPILER_TIMINGS === true) {
+            performance.mark(`${filename}:start`, {
+              detail: 'BabelPlugin:Program:start',
+            });
+          }
+          let opts = parsePluginOptions(pass.opts);
+          const isDev =
+            (typeof __DEV__ !== 'undefined' && __DEV__ === true) ||
+            process.env['NODE_ENV'] === 'development';
+          if (
+            opts.enableReanimatedCheck === true &&
+            pipelineUsesReanimatedPlugin(pass.file.opts.plugins)
+          ) {
+            opts = injectReanimatedFlag(opts);
+          }
+          if (
+            opts.environment.enableResetCacheOnSourceFileChanges !== false &&
+            isDev
+          ) {
+            opts = {
+              ...opts,
+              environment: {
+                ...opts.environment,
+                enableResetCacheOnSourceFileChanges: true,
+              },
+            };
+          }
+          const result = compileProgram(prog, {
+            opts,
+            filename: pass.filename ?? null,
+            comments: pass.file.ast.comments ?? [],
+            code: pass.file.code,
+          });
+          validateNoUntransformedReferences(
+            prog,
+            pass.filename ?? null,
+            opts.logger,
+            opts.environment,
+            result,
+          );
+          if (ENABLE_REACT_COMPILER_TIMINGS === true) {
+            performance.mark(`${filename}:end`, {
+              detail: 'BabelPlugin:Program:end',
             });
-            validateNoUntransformedReferences(
-              prog,
-              pass.filename ?? null,
-              opts.logger,
-              opts.environment,
-              result,
-            );
-            if (ENABLE_REACT_COMPILER_TIMINGS === true) {
-              performance.mark(`${filename}:end`, {
-                detail: 'BabelPlugin:Program:end',
-              });
-            }
-          } catch (e) {
-            if (e instanceof CompilerError) {
-              throw e.withPrintedMessage(pass.file.code, {eslint: false});
-            }
-            throw e;
           }
         },
         exit(_, pass): void {

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/Entrypoint/Gating.ts

@@ -51,26 +51,12 @@ function insertAdditionalFunctionDeclaration(
   CompilerError.invariant(originalFnName != null && compiled.id != null, {
     reason:
       'Expected function declarations that are referenced elsewhere to have a named identifier',
-    description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: fnPath.node.loc ?? null,
-        message: null,
-      },
-    ],
+    loc: fnPath.node.loc ?? null,
   });
   CompilerError.invariant(originalFnParams.length === compiledParams.length, {
     reason:
       'Expected React Compiler optimized function declarations to have the same number of parameters as source',
-    description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: fnPath.node.loc ?? null,
-        message: null,
-      },
-    ],
+    loc: fnPath.node.loc ?? null,
   });
 
   const gatingCondition = t.identifier(
@@ -154,13 +140,7 @@ export function insertGatedFunctionDeclaration(
     CompilerError.invariant(compiled.type === 'FunctionDeclaration', {
       reason: 'Expected compiled node type to match input type',
       description: `Got ${compiled.type} but expected FunctionDeclaration`,
-      details: [
-        {
-          kind: 'error',
-          loc: fnPath.node.loc ?? null,
-          message: null,
-        },
-      ],
+      loc: fnPath.node.loc ?? null,
     });
     insertAdditionalFunctionDeclaration(
       fnPath,

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

@@ -9,7 +9,7 @@ import {NodePath} from '@babel/core';
 import * as t from '@babel/types';
 import {Scope as BabelScope} from '@babel/traverse';
 
-import {CompilerError, ErrorCategory} from '../CompilerError';
+import {CompilerError, ErrorSeverity} from '../CompilerError';
 import {
   EnvironmentConfig,
   GeneratedSource,
@@ -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';
 
@@ -38,7 +38,7 @@ export function validateRestrictedImports(
     ImportDeclaration(importDeclPath) {
       if (restrictedImports.has(importDeclPath.node.source.value)) {
         error.push({
-          category: ErrorCategory.Todo,
+          severity: ErrorSeverity.Todo,
           reason: 'Bailing out due to blocklisted import',
           description: `Import from module ${importDeclPath.node.source.value}`,
           loc: importDeclPath.node.loc ?? null,
@@ -46,7 +46,7 @@ export function validateRestrictedImports(
       }
     },
   });
-  if (error.hasAnyErrors()) {
+  if (error.hasErrors()) {
     return error;
   } else {
     return null;
@@ -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;
@@ -205,7 +205,7 @@ export class ProgramContext {
     }
     const error = new CompilerError();
     error.push({
-      category: ErrorCategory.Todo,
+      severity: ErrorSeverity.Todo,
       reason: 'Encountered conflicting global in generated program',
       description: `Conflict from local binding ${name}`,
       loc: scope.getBinding(name)?.path.node.loc ?? null,
@@ -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),
   );
@@ -256,14 +256,8 @@ export function addImportsToProgram(
         {
           reason:
             'Encountered conflicting import specifiers in generated program',
-          description: `Conflict from import ${loweredImport.module}:(${loweredImport.imported} as ${loweredImport.name})`,
-          details: [
-            {
-              kind: 'error',
-              loc: GeneratedSource,
-              message: null,
-            },
-          ],
+          description: `Conflict from import ${loweredImport.module}:(${loweredImport.imported} as ${loweredImport.name}).`,
+          loc: GeneratedSource,
           suggestions: null,
         },
       );
@@ -274,13 +268,7 @@ export function addImportsToProgram(
           reason:
             'Found inconsistent import specifier. This is an internal bug.',
           description: `Expected import ${moduleName}:${specifierName} but found ${loweredImport.module}:${loweredImport.imported}`,
-          details: [
-            {
-              kind: 'error',
-              loc: GeneratedSource,
-              message: null,
-            },
-          ],
+          loc: GeneratedSource,
         },
       );
     }
@@ -303,29 +291,9 @@ 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

@@ -6,13 +6,8 @@
  */
 
 import * as t from '@babel/types';
-import {z} from 'zod/v4';
-import {
-  CompilerDiagnostic,
-  CompilerError,
-  CompilerErrorDetail,
-  CompilerErrorDetailOptions,
-} from '../CompilerError';
+import {z} from 'zod';
+import {CompilerError, CompilerErrorDetailOptions} from '../CompilerError';
 import {
   EnvironmentConfig,
   ExternalFunction,
@@ -20,7 +15,7 @@ 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 +46,8 @@ 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;
 
@@ -135,12 +130,7 @@ export type PluginOptions = Partial<{
    */
   eslintSuppressionRules: Array<string> | null | undefined;
 
-  /**
-   * Whether to report "suppression" errors for Flow suppressions. If false, suppression errors
-   * are only emitted for ESLint suppressions
-   */
   flowSuppressions: boolean;
-
   /*
    * Ignore 'use no forget' annotations. Helpful during testing but should not be used in production.
    */
@@ -166,11 +156,7 @@ 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'),
@@ -238,7 +224,7 @@ export type LoggerEvent =
 export type CompileErrorEvent = {
   kind: 'CompileError';
   fnLoc: t.SourceLocation | null;
-  detail: CompilerErrorDetail | CompilerDiagnostic;
+  detail: CompilerErrorDetailOptions;
 };
 export type CompileDiagnosticEvent = {
   kind: 'CompileDiagnostic';
@@ -286,7 +272,7 @@ export type Logger = {
   debugLogIRs?: (value: CompilerPipelineValue) => void;
 };
 
-export const defaultOptions: ParsedPluginOptions = {
+export const defaultOptions: PluginOptions = {
   compilationMode: 'infer',
   panicThreshold: 'none',
   environment: parseEnvironmentConfig({}).unwrap(),
@@ -303,9 +289,9 @@ 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

@@ -33,7 +33,9 @@ import {findContextIdentifiers} from '../HIR/FindContextIdentifiers';
 import {
   analyseFunctions,
   dropManualMemoization,
+  inferMutableRanges,
   inferReactivePlaces,
+  inferReferenceEffects,
   inlineImmediatelyInvokedFunctionExpressions,
   inferEffectDependencies,
 } from '../Inference';
@@ -90,20 +92,18 @@ import {
 } from '../Validation';
 import {validateLocalsNotReassignedAfterRender} from '../Validation/ValidateLocalsNotReassignedAfterRender';
 import {outlineFunctions} from '../Optimization/OutlineFunctions';
+import {propagatePhiTypes} from '../TypeInference/PropagatePhiTypes';
 import {lowerContextAccess} from '../Optimization/LowerContextAccess';
-import {validateNoSetStateInEffects} from '../Validation/ValidateNoSetStateInEffects';
+import {validateNoSetStateInPassiveEffects} from '../Validation/ValidateNoSetStateInPassiveEffects';
 import {validateNoJSXInTryStatement} from '../Validation/ValidateNoJSXInTryStatement';
 import {propagateScopeDependenciesHIR} from '../HIR/PropagateScopeDependenciesHIR';
 import {outlineJSX} from '../Optimization/OutlineJsx';
 import {optimizePropsMethodCalls} from '../Optimization/OptimizePropsMethodCalls';
 import {transformFire} from '../Transform';
 import {validateNoImpureFunctionsInRender} from '../Validation/ValidateNoImpureFunctionsInRender';
+import {CompilerError} from '..';
 import {validateStaticComponents} from '../Validation/ValidateStaticComponents';
 import {validateNoFreezingKnownMutableFunctions} from '../Validation/ValidateNoFreezingKnownMutableFunctions';
-import {inferMutationAliasingEffects} from '../Inference/InferMutationAliasingEffects';
-import {inferMutationAliasingRanges} from '../Inference/InferMutationAliasingRanges';
-import {validateNoDerivedComputationsInEffects} from '../Validation/ValidateNoDerivedComputationsInEffects';
-import {nameAnonymousFunctions} from '../Transform/NameAnonymousFunctions';
 
 export type CompilerPipelineValue =
   | {kind: 'ast'; name: string; value: CodegenFunction}
@@ -172,7 +172,7 @@ function runWithEnvironment(
     !env.config.disableMemoizationForDebugging &&
     !env.config.enableChangeDetectionForDebugging
   ) {
-    dropManualMemoization(hir).unwrap();
+    dropManualMemoization(hir);
     log({kind: 'hir', name: 'DropManualMemoization', value: hir});
   }
 
@@ -227,13 +227,15 @@ function runWithEnvironment(
   analyseFunctions(hir);
   log({kind: 'hir', name: 'AnalyseFunctions', value: hir});
 
-  const mutabilityAliasingErrors = inferMutationAliasingEffects(hir);
-  log({kind: 'hir', name: 'InferMutationAliasingEffects', value: hir});
+  const fnEffectErrors = inferReferenceEffects(hir);
   if (env.isInferredMemoEnabled) {
-    if (mutabilityAliasingErrors.isErr()) {
-      throw mutabilityAliasingErrors.unwrapErr();
+    if (fnEffectErrors.length > 0) {
+      CompilerError.throw(fnEffectErrors[0]);
     }
   }
+  log({kind: 'hir', name: 'InferReferenceEffects', value: hir});
+
+  validateLocalsNotReassignedAfterRender(hir);
 
   // Note: Has to come after infer reference effects because "dead" code may still affect inference
   deadCodeElimination(hir);
@@ -247,16 +249,8 @@ function runWithEnvironment(
   pruneMaybeThrows(hir);
   log({kind: 'hir', name: 'PruneMaybeThrows', value: hir});
 
-  const mutabilityAliasingRangeErrors = inferMutationAliasingRanges(hir, {
-    isFunctionExpression: false,
-  });
-  log({kind: 'hir', name: 'InferMutationAliasingRanges', value: hir});
-  if (env.isInferredMemoEnabled) {
-    if (mutabilityAliasingRangeErrors.isErr()) {
-      throw mutabilityAliasingRangeErrors.unwrapErr();
-    }
-    validateLocalsNotReassignedAfterRender(hir);
-  }
+  inferMutableRanges(hir);
+  log({kind: 'hir', name: 'InferMutableRanges', value: hir});
 
   if (env.isInferredMemoEnabled) {
     if (env.config.assertValidMutableRanges) {
@@ -271,12 +265,8 @@ function runWithEnvironment(
       validateNoSetStateInRender(hir).unwrap();
     }
 
-    if (env.config.validateNoDerivedComputationsInEffects) {
-      validateNoDerivedComputationsInEffects(hir);
-    }
-
-    if (env.config.validateNoSetStateInEffects) {
-      env.logErrors(validateNoSetStateInEffects(hir, env));
+    if (env.config.validateNoSetStateInPassiveEffects) {
+      env.logErrors(validateNoSetStateInPassiveEffects(hir));
     }
 
     if (env.config.validateNoJSXInTryStatements) {
@@ -287,7 +277,9 @@ function runWithEnvironment(
       validateNoImpureFunctionsInRender(hir).unwrap();
     }
 
-    validateNoFreezingKnownMutableFunctions(hir).unwrap();
+    if (env.config.validateNoFreezingKnownMutableFunctions) {
+      validateNoFreezingKnownMutableFunctions(hir).unwrap();
+    }
   }
 
   inferReactivePlaces(hir);
@@ -300,6 +292,13 @@ function runWithEnvironment(
     value: hir,
   });
 
+  propagatePhiTypes(hir);
+  log({
+    kind: 'hir',
+    name: 'PropagatePhiTypes',
+    value: hir,
+  });
+
   if (env.isInferredMemoEnabled) {
     if (env.config.validateStaticComponents) {
       env.logErrors(validateStaticComponents(hir));
@@ -325,15 +324,6 @@ function runWithEnvironment(
     outlineJSX(hir);
   }
 
-  if (env.config.enableNameAnonymousFunctions) {
-    nameAnonymousFunctions(hir);
-    log({
-      kind: 'hir',
-      name: 'NameAnonymousFunctions',
-      value: hir,
-    });
-  }
-
   if (env.config.enableFunctionOutlining) {
     outlineFunctions(hir, fbtOperands);
     log({kind: 'hir', name: 'OutlineFunctions', value: hir});

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

@@ -10,7 +10,7 @@ import * as t from '@babel/types';
 import {
   CompilerError,
   CompilerErrorDetail,
-  ErrorCategory,
+  ErrorSeverity,
 } from '../CompilerError';
 import {ExternalFunction, ReactFunctionType} from '../HIR/Environment';
 import {CodegenFunction} from '../ReactiveScopes';
@@ -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;
@@ -108,14 +104,14 @@ function findDirectivesDynamicGating(
         errors.push({
           reason: `Dynamic gating directive is not a valid JavaScript identifier`,
           description: `Found '${directive.value.value}'`,
-          category: ErrorCategory.Gating,
+          severity: ErrorSeverity.InvalidReact,
           loc: directive.loc ?? null,
           suggestions: null,
         });
       }
     }
   }
-  if (errors.hasAnyErrors()) {
+  if (errors.hasErrors()) {
     return Err(errors);
   } else if (result.length > 1) {
     const error = new CompilerError();
@@ -124,7 +120,7 @@ function findDirectivesDynamicGating(
       description: `Expected a single directive but found [${result
         .map(r => r.directive.value.value)
         .join(', ')}]`,
-      category: ErrorCategory.Gating,
+      severity: ErrorSeverity.InvalidReact,
       loc: result[0].directive.loc ?? null,
       suggestions: null,
     });
@@ -142,13 +138,15 @@ function findDirectivesDynamicGating(
   }
 }
 
-function isError(err: unknown): boolean {
-  return !(err instanceof CompilerError) || err.hasErrors();
+function isCriticalError(err: unknown): boolean {
+  return !(err instanceof CompilerError) || err.isCritical();
 }
 
 function isConfigError(err: unknown): boolean {
   if (err instanceof CompilerError) {
-    return err.details.some(detail => detail.category === ErrorCategory.Config);
+    return err.details.some(
+      detail => detail.severity === ErrorSeverity.InvalidConfig,
+    );
   }
   return false;
 }
@@ -183,7 +181,7 @@ function logError(
         context.opts.logger.logEvent(context.filename, {
           kind: 'CompileError',
           fnLoc,
-          detail,
+          detail: detail.options,
         });
       }
     } else {
@@ -213,7 +211,8 @@ function handleError(
   logError(err, context, fnLoc);
   if (
     context.opts.panicThreshold === 'all_errors' ||
-    (context.opts.panicThreshold === 'critical_errors' && isError(err)) ||
+    (context.opts.panicThreshold === 'critical_errors' &&
+      isCriticalError(err)) ||
     isConfigError(err) // Always throws regardless of panic threshold
   ) {
     throw err;
@@ -314,13 +313,7 @@ function insertNewOutlinedFunctionNode(
       CompilerError.invariant(insertedFuncDecl.isFunctionDeclaration(), {
         reason: 'Expected inserted function declaration',
         description: `Got: ${insertedFuncDecl}`,
-        details: [
-          {
-            kind: 'error',
-            loc: insertedFuncDecl.node?.loc ?? null,
-            message: null,
-          },
-        ],
+        loc: insertedFuncDecl.node?.loc ?? null,
       });
       return insertedFuncDecl;
     }
@@ -429,14 +422,7 @@ export function compileProgram(
       for (const outlined of compiled.outlined) {
         CompilerError.invariant(outlined.fn.outlined.length === 0, {
           reason: 'Unexpected nested outlined functions',
-          description: null,
-          details: [
-            {
-              kind: 'error',
-              loc: outlined.fn.loc,
-              message: null,
-            },
-          ],
+          loc: outlined.fn.loc,
         });
         const fn = insertNewOutlinedFunctionNode(
           program,
@@ -469,7 +455,7 @@ export function compileProgram(
         new CompilerErrorDetail({
           reason:
             'Unexpected compiled functions when module scope opt-out is present',
-          category: ErrorCategory.Invariant,
+          severity: ErrorSeverity.Invariant,
           loc: null,
         }),
       );
@@ -504,20 +490,7 @@ function findFunctionsToCompile(
 ): Array<CompileSource> {
   const queue: Array<CompileSource> = [];
   const traverseFunction = (fn: BabelFn, pass: CompilerPass): void => {
-    // In 'all' mode, compile only top level functions
-    if (
-      pass.opts.compilationMode === 'all' &&
-      fn.scope.getProgramParent() !== fn.scope.parent
-    ) {
-      return;
-    }
-
     const fnType = getReactFunctionType(fn, pass);
-
-    if (pass.opts.environment.validateNoDynamicallyCreatedComponentsOrHooks) {
-      validateNoDynamicallyCreatedComponentsOrHooks(fn, pass, programContext);
-    }
-
     if (fnType === null || programContext.alreadyCompiled.has(fn.node)) {
       return;
     }
@@ -837,7 +810,7 @@ function shouldSkipCompilation(
           reason: `Expected a filename but found none.`,
           description:
             "When the 'sources' config options is specified, the React compiler will only compile files with a name",
-          category: ErrorCategory.Config,
+          severity: ErrorSeverity.InvalidConfig,
           loc: null,
         }),
       );
@@ -861,72 +834,6 @@ function shouldSkipCompilation(
   return false;
 }
 
-/**
- * Validates that Components/Hooks are always defined at module level. This prevents scope reference
- * errors that occur when the compiler attempts to optimize the nested component/hook while its
- * parent function remains uncompiled.
- */
-function validateNoDynamicallyCreatedComponentsOrHooks(
-  fn: BabelFn,
-  pass: CompilerPass,
-  programContext: ProgramContext,
-): void {
-  const parentNameExpr = getFunctionName(fn);
-  const parentName =
-    parentNameExpr !== null && parentNameExpr.isIdentifier()
-      ? parentNameExpr.node.name
-      : '<anonymous>';
-
-  const validateNestedFunction = (
-    nestedFn: NodePath<
-      t.FunctionDeclaration | t.FunctionExpression | t.ArrowFunctionExpression
-    >,
-  ): void => {
-    if (
-      nestedFn.node === fn.node ||
-      programContext.alreadyCompiled.has(nestedFn.node)
-    ) {
-      return;
-    }
-
-    if (nestedFn.scope.getProgramParent() !== nestedFn.scope.parent) {
-      const nestedFnType = getReactFunctionType(nestedFn as BabelFn, pass);
-      const nestedFnNameExpr = getFunctionName(nestedFn as BabelFn);
-      const nestedName =
-        nestedFnNameExpr !== null && nestedFnNameExpr.isIdentifier()
-          ? nestedFnNameExpr.node.name
-          : '<anonymous>';
-      if (nestedFnType === 'Component' || nestedFnType === 'Hook') {
-        CompilerError.throwDiagnostic({
-          category: ErrorCategory.Factories,
-          reason: `Components and hooks cannot be created dynamically`,
-          description: `The function \`${nestedName}\` appears to be a React ${nestedFnType.toLowerCase()}, but it's defined inside \`${parentName}\`. Components and Hooks should always be declared at module scope`,
-          details: [
-            {
-              kind: 'error',
-              message: 'this function dynamically created a component/hook',
-              loc: parentNameExpr?.node.loc ?? fn.node.loc ?? null,
-            },
-            {
-              kind: 'error',
-              message: 'the component is created here',
-              loc: nestedFnNameExpr?.node.loc ?? nestedFn.node.loc ?? null,
-            },
-          ],
-        });
-      }
-    }
-
-    nestedFn.skip();
-  };
-
-  fn.traverse({
-    FunctionDeclaration: validateNestedFunction,
-    FunctionExpression: validateNestedFunction,
-    ArrowFunctionExpression: validateNestedFunction,
-  });
-}
-
 function getReactFunctionType(
   fn: BabelFn,
   pass: CompilerPass,
@@ -965,6 +872,11 @@ function getReactFunctionType(
       return componentSyntaxType;
     }
     case 'all': {
+      // Compile only top level functions
+      if (fn.scope.getProgramParent() !== fn.scope.parent) {
+        return null;
+      }
+
       return getComponentOrHookLike(fn, hookPattern) ?? 'Other';
     }
     default: {
@@ -1424,13 +1336,7 @@ export function getReactCompilerRuntimeModule(
       {
         reason: 'Expected target to already be validated',
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       },
     );

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/Entrypoint/Suppression.ts

@@ -8,10 +8,10 @@
 import {NodePath} from '@babel/core';
 import * as t from '@babel/types';
 import {
-  CompilerDiagnostic,
   CompilerError,
+  CompilerErrorDetail,
   CompilerSuggestionOperation,
-  ErrorCategory,
+  ErrorSeverity,
 } from '../CompilerError';
 import {assertExhaustive} from '../Utils/utils';
 import {GeneratedSource} from '../HIR';
@@ -86,18 +86,12 @@ export function findProgramSuppressions(
   let enableComment: t.Comment | null = null;
   let source: SuppressionSource | null = null;
 
-  let disableNextLinePattern: RegExp | null = null;
-  let disablePattern: RegExp | null = null;
-  let enablePattern: RegExp | null = null;
-  if (ruleNames.length !== 0) {
-    const rulePattern = `(${ruleNames.join('|')})`;
-    disableNextLinePattern = new RegExp(
-      `eslint-disable-next-line ${rulePattern}`,
-    );
-    disablePattern = new RegExp(`eslint-disable ${rulePattern}`);
-    enablePattern = new RegExp(`eslint-enable ${rulePattern}`);
-  }
-
+  const rulePattern = `(${ruleNames.join('|')})`;
+  const disableNextLinePattern = new RegExp(
+    `eslint-disable-next-line ${rulePattern}`,
+  );
+  const disablePattern = new RegExp(`eslint-disable ${rulePattern}`);
+  const enablePattern = new RegExp(`eslint-enable ${rulePattern}`);
   const flowSuppressionPattern = new RegExp(
     '\\$(FlowFixMe\\w*|FlowExpectedError|FlowIssue)\\[react\\-rule',
   );
@@ -113,7 +107,6 @@ export function findProgramSuppressions(
        * CommentLine within the block.
        */
       disableComment == null &&
-      disableNextLinePattern != null &&
       disableNextLinePattern.test(comment.value)
     ) {
       disableComment = comment;
@@ -131,16 +124,12 @@ export function findProgramSuppressions(
       source = 'Flow';
     }
 
-    if (disablePattern != null && disablePattern.test(comment.value)) {
+    if (disablePattern.test(comment.value)) {
       disableComment = comment;
       source = 'Eslint';
     }
 
-    if (
-      enablePattern != null &&
-      enablePattern.test(comment.value) &&
-      source === 'Eslint'
-    ) {
+    if (enablePattern.test(comment.value) && source === 'Eslint') {
       enableComment = comment;
     }
 
@@ -163,14 +152,7 @@ export function suppressionsToCompilerError(
 ): CompilerError {
   CompilerError.invariant(suppressionRanges.length !== 0, {
     reason: `Expected at least suppression comment source range`,
-    description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: GeneratedSource,
-        message: null,
-      },
-    ],
+    loc: GeneratedSource,
   });
   const error = new CompilerError();
   for (const suppressionRange of suppressionRanges) {
@@ -199,11 +181,12 @@ export function suppressionsToCompilerError(
           'Unhandled suppression source',
         );
     }
-    error.pushDiagnostic(
-      CompilerDiagnostic.create({
-        reason: reason,
-        description: `React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression \`${suppressionRange.disableComment.value.trim()}\``,
-        category: ErrorCategory.Suppression,
+    error.pushErrorDetail(
+      new CompilerErrorDetail({
+        reason: `${reason}. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior`,
+        description: suppressionRange.disableComment.value.trim(),
+        severity: ErrorSeverity.InvalidReact,
+        loc: suppressionRange.disableComment.loc ?? null,
         suggestions: [
           {
             description: suggestion,
@@ -214,10 +197,6 @@ export function suppressionsToCompilerError(
             op: CompilerSuggestionOperation.Remove,
           },
         ],
-      }).withDetails({
-        kind: 'error',
-        loc: suppressionRange.disableComment.loc ?? null,
-        message: 'Found React rule suppression',
       }),
     );
   }

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

@@ -8,63 +8,35 @@
 import {NodePath} from '@babel/core';
 import * as t from '@babel/types';
 
-import {CompilerError, EnvironmentConfig, Logger} from '..';
+import {
+  CompilerError,
+  CompilerErrorDetailOptions,
+  EnvironmentConfig,
+  ErrorSeverity,
+  Logger,
+} from '..';
 import {getOrInsertWith} from '../Utils/utils';
-import {Environment, GeneratedSource} from '../HIR';
+import {Environment} from '../HIR';
 import {DEFAULT_EXPORT} from '../HIR/Environment';
 import {CompileProgramMetadata} from './Program';
-import {
-  CompilerDiagnostic,
-  CompilerDiagnosticOptions,
-  ErrorCategory,
-} from '../CompilerError';
 
 function throwInvalidReact(
-  options: CompilerDiagnosticOptions,
+  options: Omit<CompilerErrorDetailOptions, 'severity'>,
   {logger, filename}: TraversalState,
 ): never {
+  const detail: CompilerErrorDetailOptions = {
+    ...options,
+    severity: ErrorSeverity.InvalidReact,
+  };
   logger?.logEvent(filename, {
     kind: 'CompileError',
     fnLoc: null,
-    detail: new CompilerDiagnostic(options),
+    detail,
   });
-  CompilerError.throwDiagnostic(options);
-}
-
-function isAutodepsSigil(
-  arg: NodePath<t.ArgumentPlaceholder | t.SpreadElement | t.Expression>,
-): boolean {
-  // Check for AUTODEPS identifier imported from React
-  if (arg.isIdentifier() && arg.node.name === 'AUTODEPS') {
-    const binding = arg.scope.getBinding(arg.node.name);
-    if (binding && binding.path.isImportSpecifier()) {
-      const importSpecifier = binding.path.node as t.ImportSpecifier;
-      if (importSpecifier.imported.type === 'Identifier') {
-        return (importSpecifier.imported as t.Identifier).name === 'AUTODEPS';
-      }
-    }
-    return false;
-  }
-
-  // Check for React.AUTODEPS member expression
-  if (arg.isMemberExpression() && !arg.node.computed) {
-    const object = arg.get('object');
-    const property = arg.get('property');
-
-    if (
-      object.isIdentifier() &&
-      object.node.name === 'React' &&
-      property.isIdentifier() &&
-      property.node.name === 'AUTODEPS'
-    ) {
-      return true;
-    }
-  }
-
-  return false;
+  CompilerError.throw(detail);
 }
 function assertValidEffectImportReference(
-  autodepsIndex: number,
+  numArgs: number,
   paths: Array<NodePath<t.Node>>,
   context: TraversalState,
 ): void {
@@ -77,10 +49,11 @@ function assertValidEffectImportReference(
         maybeCalleeLoc != null &&
         context.inferredEffectLocations.has(maybeCalleeLoc);
       /**
-       * Error on effect calls that still have AUTODEPS in their args
+       * Only error on untransformed references of the form `useMyEffect(...)`
+       * or `moduleNamespace.useMyEffect(...)`, with matching argument counts.
+       * TODO: do we also want a mode to also hard error on non-call references?
        */
-      const hasAutodepsArg = args.some(isAutodepsSigil);
-      if (hasAutodepsArg && !hasInferredEffect) {
+      if (args.length === numArgs && !hasInferredEffect) {
         const maybeErrorDiagnostic = matchCompilerDiagnostic(
           path,
           context.transformErrors,
@@ -92,19 +65,14 @@ function assertValidEffectImportReference(
          */
         throwInvalidReact(
           {
-            category: ErrorCategory.AutomaticEffectDependencies,
             reason:
-              'Cannot infer dependencies of this effect. This will break your build!',
-            description:
-              'To resolve, either pass a dependency array or fix reported compiler bailout diagnostics' +
-              (maybeErrorDiagnostic ? ` ${maybeErrorDiagnostic}` : ''),
-            details: [
-              {
-                kind: 'error',
-                message: 'Cannot infer dependencies',
-                loc: parent.node.loc ?? GeneratedSource,
-              },
-            ],
+              '[InferEffectDependencies] React Compiler is unable to infer dependencies of this effect. ' +
+              'This will break your build! ' +
+              'To resolve, either pass your own dependency array or fix reported compiler bailout diagnostics.',
+            description: maybeErrorDiagnostic
+              ? `(Bailout reason: ${maybeErrorDiagnostic})`
+              : null,
+            loc: parent.node.loc ?? null,
           },
           context,
         );
@@ -124,18 +92,13 @@ function assertValidFireImportReference(
     );
     throwInvalidReact(
       {
-        category: ErrorCategory.Fire,
-        reason: '[Fire] Untransformed reference to compiler-required feature.',
-        description:
-          'Either remove this `fire` call or ensure it is successfully transformed by the compiler' +
-          (maybeErrorDiagnostic != null ? ` ${maybeErrorDiagnostic}` : ''),
-        details: [
-          {
-            kind: 'error',
-            message: 'Untransformed `fire` call',
-            loc: paths[0].node.loc ?? GeneratedSource,
-          },
-        ],
+        reason:
+          '[Fire] Untransformed reference to compiler-required feature. ' +
+          'Either remove this `fire` call or ensure it is successfully transformed by the compiler',
+        description: maybeErrorDiagnostic
+          ? `(Bailout reason: ${maybeErrorDiagnostic})`
+          : null,
+        loc: paths[0].node.loc ?? null,
       },
       context,
     );
@@ -165,12 +128,12 @@ export default function validateNoUntransformedReferences(
   if (env.inferEffectDependencies) {
     for (const {
       function: {source, importSpecifierName},
-      autodepsIndex,
+      numRequiredArgs,
     } of env.inferEffectDependencies) {
       const module = getOrInsertWith(moduleLoadChecks, source, () => new Map());
       module.set(
         importSpecifierName,
-        assertValidEffectImportReference.bind(null, autodepsIndex),
+        assertValidEffectImportReference.bind(null, numRequiredArgs),
       );
     }
   }
@@ -215,14 +178,7 @@ function validateImportSpecifier(
   const binding = local.scope.getBinding(local.node.name);
   CompilerError.invariant(binding != null, {
     reason: 'Expected binding to be found for import specifier',
-    description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: local.node.loc ?? null,
-        message: null,
-      },
-    ],
+    loc: local.node.loc ?? null,
   });
   checkFn(binding.referencePaths, state);
 }
@@ -242,14 +198,7 @@ function validateNamespacedImport(
 
   CompilerError.invariant(binding != null, {
     reason: 'Expected binding to be found for import specifier',
-    description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: local.node.loc ?? null,
-        message: null,
-      },
-    ],
+    loc: local.node.loc ?? null,
   });
   const filteredReferences = new Map<
     CheckInvalidReferenceFn,

compiler/packages/babel-plugin-react-compiler/src/Flood/FlowTypes.ts

@@ -1,752 +0,0 @@
-/**
- * TypeScript definitions for Flow type JSON representations
- * Based on the output of /data/sandcastle/boxes/fbsource/fbcode/flow/src/typing/convertTypes.ml
- */
-
-// Base type for all Flow types with a kind field
-export interface BaseFlowType {
-  kind: string;
-}
-
-// Type for representing polarity
-export type Polarity = 'positive' | 'negative' | 'neutral';
-
-// Type for representing a name that might be null
-export type OptionalName = string | null;
-
-// Open type
-export interface OpenType extends BaseFlowType {
-  kind: 'Open';
-}
-
-// Def type
-export interface DefType extends BaseFlowType {
-  kind: 'Def';
-  def: DefT;
-}
-
-// Eval type
-export interface EvalType extends BaseFlowType {
-  kind: 'Eval';
-  type: FlowType;
-  destructor: Destructor;
-}
-
-// Generic type
-export interface GenericType extends BaseFlowType {
-  kind: 'Generic';
-  name: string;
-  bound: FlowType;
-  no_infer: boolean;
-}
-
-// ThisInstance type
-export interface ThisInstanceType extends BaseFlowType {
-  kind: 'ThisInstance';
-  instance: InstanceT;
-  is_this: boolean;
-  name: string;
-}
-
-// ThisTypeApp type
-export interface ThisTypeAppType extends BaseFlowType {
-  kind: 'ThisTypeApp';
-  t1: FlowType;
-  t2: FlowType;
-  t_list?: Array<FlowType>;
-}
-
-// TypeApp type
-export interface TypeAppType extends BaseFlowType {
-  kind: 'TypeApp';
-  type: FlowType;
-  targs: Array<FlowType>;
-  from_value: boolean;
-  use_desc: boolean;
-}
-
-// FunProto type
-export interface FunProtoType extends BaseFlowType {
-  kind: 'FunProto';
-}
-
-// ObjProto type
-export interface ObjProtoType extends BaseFlowType {
-  kind: 'ObjProto';
-}
-
-// NullProto type
-export interface NullProtoType extends BaseFlowType {
-  kind: 'NullProto';
-}
-
-// FunProtoBind type
-export interface FunProtoBindType extends BaseFlowType {
-  kind: 'FunProtoBind';
-}
-
-// Intersection type
-export interface IntersectionType extends BaseFlowType {
-  kind: 'Intersection';
-  members: Array<FlowType>;
-}
-
-// Union type
-export interface UnionType extends BaseFlowType {
-  kind: 'Union';
-  members: Array<FlowType>;
-}
-
-// Maybe type
-export interface MaybeType extends BaseFlowType {
-  kind: 'Maybe';
-  type: FlowType;
-}
-
-// Optional type
-export interface OptionalType extends BaseFlowType {
-  kind: 'Optional';
-  type: FlowType;
-  use_desc: boolean;
-}
-
-// Keys type
-export interface KeysType extends BaseFlowType {
-  kind: 'Keys';
-  type: FlowType;
-}
-
-// Annot type
-export interface AnnotType extends BaseFlowType {
-  kind: 'Annot';
-  type: FlowType;
-  use_desc: boolean;
-}
-
-// Opaque type
-export interface OpaqueType extends BaseFlowType {
-  kind: 'Opaque';
-  opaquetype: {
-    opaque_id: string;
-    underlying_t: FlowType | null;
-    super_t: FlowType | null;
-    opaque_type_args: Array<{
-      name: string;
-      type: FlowType;
-      polarity: Polarity;
-    }>;
-    opaque_name: string;
-  };
-}
-
-// Namespace type
-export interface NamespaceType extends BaseFlowType {
-  kind: 'Namespace';
-  namespace_symbol: {
-    symbol: string;
-  };
-  values_type: FlowType;
-  types_tmap: PropertyMap;
-}
-
-// Any type
-export interface AnyType extends BaseFlowType {
-  kind: 'Any';
-}
-
-// StrUtil type
-export interface StrUtilType extends BaseFlowType {
-  kind: 'StrUtil';
-  op: 'StrPrefix' | 'StrSuffix';
-  prefix?: string;
-  suffix?: string;
-  remainder?: FlowType;
-}
-
-// TypeParam definition
-export interface TypeParam {
-  name: string;
-  bound: FlowType;
-  polarity: Polarity;
-  default: FlowType | null;
-}
-
-// EnumInfo types
-export type EnumInfo = ConcreteEnum | AbstractEnum;
-
-export interface ConcreteEnum {
-  kind: 'ConcreteEnum';
-  enum_name: string;
-  enum_id: string;
-  members: Array<string>;
-  representation_t: FlowType;
-  has_unknown_members: boolean;
-}
-
-export interface AbstractEnum {
-  kind: 'AbstractEnum';
-  representation_t: FlowType;
-}
-
-// CanonicalRendersForm types
-export type CanonicalRendersForm =
-  | InstrinsicRenders
-  | NominalRenders
-  | StructuralRenders
-  | DefaultRenders;
-
-export interface InstrinsicRenders {
-  kind: 'InstrinsicRenders';
-  name: string;
-}
-
-export interface NominalRenders {
-  kind: 'NominalRenders';
-  renders_id: string;
-  renders_name: string;
-  renders_super: FlowType;
-}
-
-export interface StructuralRenders {
-  kind: 'StructuralRenders';
-  renders_variant: 'RendersNormal' | 'RendersMaybe' | 'RendersStar';
-  renders_structural_type: FlowType;
-}
-
-export interface DefaultRenders {
-  kind: 'DefaultRenders';
-}
-
-// InstanceT definition
-export interface InstanceT {
-  inst: InstType;
-  static: FlowType;
-  super: FlowType;
-  implements: Array<FlowType>;
-}
-
-// InstType definition
-export interface InstType {
-  class_name: string | null;
-  class_id: string;
-  type_args: Array<{
-    name: string;
-    type: FlowType;
-    polarity: Polarity;
-  }>;
-  own_props: PropertyMap;
-  proto_props: PropertyMap;
-  call_t: null | {
-    id: number;
-    call: FlowType;
-  };
-}
-
-// DefT types
-export type DefT =
-  | NumGeneralType
-  | StrGeneralType
-  | BoolGeneralType
-  | BigIntGeneralType
-  | EmptyType
-  | MixedType
-  | NullType
-  | VoidType
-  | SymbolType
-  | FunType
-  | ObjType
-  | ArrType
-  | ClassType
-  | InstanceType
-  | SingletonStrType
-  | NumericStrKeyType
-  | SingletonNumType
-  | SingletonBoolType
-  | SingletonBigIntType
-  | TypeType
-  | PolyType
-  | ReactAbstractComponentType
-  | RendersType
-  | EnumValueType
-  | EnumObjectType;
-
-export interface NumGeneralType extends BaseFlowType {
-  kind: 'NumGeneral';
-}
-
-export interface StrGeneralType extends BaseFlowType {
-  kind: 'StrGeneral';
-}
-
-export interface BoolGeneralType extends BaseFlowType {
-  kind: 'BoolGeneral';
-}
-
-export interface BigIntGeneralType extends BaseFlowType {
-  kind: 'BigIntGeneral';
-}
-
-export interface EmptyType extends BaseFlowType {
-  kind: 'Empty';
-}
-
-export interface MixedType extends BaseFlowType {
-  kind: 'Mixed';
-}
-
-export interface NullType extends BaseFlowType {
-  kind: 'Null';
-}
-
-export interface VoidType extends BaseFlowType {
-  kind: 'Void';
-}
-
-export interface SymbolType extends BaseFlowType {
-  kind: 'Symbol';
-}
-
-export interface FunType extends BaseFlowType {
-  kind: 'Fun';
-  static: FlowType;
-  funtype: FunTypeObj;
-}
-
-export interface ObjType extends BaseFlowType {
-  kind: 'Obj';
-  objtype: ObjTypeObj;
-}
-
-export interface ArrType extends BaseFlowType {
-  kind: 'Arr';
-  arrtype: ArrTypeObj;
-}
-
-export interface ClassType extends BaseFlowType {
-  kind: 'Class';
-  type: FlowType;
-}
-
-export interface InstanceType extends BaseFlowType {
-  kind: 'Instance';
-  instance: InstanceT;
-}
-
-export interface SingletonStrType extends BaseFlowType {
-  kind: 'SingletonStr';
-  from_annot: boolean;
-  value: string;
-}
-
-export interface NumericStrKeyType extends BaseFlowType {
-  kind: 'NumericStrKey';
-  number: string;
-  string: string;
-}
-
-export interface SingletonNumType extends BaseFlowType {
-  kind: 'SingletonNum';
-  from_annot: boolean;
-  number: string;
-  string: string;
-}
-
-export interface SingletonBoolType extends BaseFlowType {
-  kind: 'SingletonBool';
-  from_annot: boolean;
-  value: boolean;
-}
-
-export interface SingletonBigIntType extends BaseFlowType {
-  kind: 'SingletonBigInt';
-  from_annot: boolean;
-  value: string;
-}
-
-export interface TypeType extends BaseFlowType {
-  kind: 'Type';
-  type_kind: TypeTKind;
-  type: FlowType;
-}
-
-export type TypeTKind =
-  | 'TypeAliasKind'
-  | 'TypeParamKind'
-  | 'OpaqueKind'
-  | 'ImportTypeofKind'
-  | 'ImportClassKind'
-  | 'ImportEnumKind'
-  | 'InstanceKind'
-  | 'RenderTypeKind';
-
-export interface PolyType extends BaseFlowType {
-  kind: 'Poly';
-  tparams: Array<TypeParam>;
-  t_out: FlowType;
-  id: string;
-}
-
-export interface ReactAbstractComponentType extends BaseFlowType {
-  kind: 'ReactAbstractComponent';
-  config: FlowType;
-  renders: FlowType;
-  instance: ComponentInstance;
-  component_kind: ComponentKind;
-}
-
-export type ComponentInstance =
-  | {kind: 'RefSetterProp'; type: FlowType}
-  | {kind: 'Omitted'};
-
-export type ComponentKind =
-  | {kind: 'Structural'}
-  | {kind: 'Nominal'; id: string; name: string; types: Array<FlowType> | null};
-
-export interface RendersType extends BaseFlowType {
-  kind: 'Renders';
-  form: CanonicalRendersForm;
-}
-
-export interface EnumValueType extends BaseFlowType {
-  kind: 'EnumValue';
-  enum_info: EnumInfo;
-}
-
-export interface EnumObjectType extends BaseFlowType {
-  kind: 'EnumObject';
-  enum_value_t: FlowType;
-  enum_info: EnumInfo;
-}
-
-// ObjKind types
-export type ObjKind =
-  | {kind: 'Exact'}
-  | {kind: 'Inexact'}
-  | {kind: 'Indexed'; dicttype: DictType};
-
-// DictType definition
-export interface DictType {
-  dict_name: string | null;
-  key: FlowType;
-  value: FlowType;
-  dict_polarity: Polarity;
-}
-
-// ArrType types
-export type ArrTypeObj = ArrayAT | TupleAT | ROArrayAT;
-
-export interface ArrayAT {
-  kind: 'ArrayAT';
-  elem_t: FlowType;
-}
-
-export interface TupleAT {
-  kind: 'TupleAT';
-  elem_t: FlowType;
-  elements: Array<TupleElement>;
-  min_arity: number;
-  max_arity: number;
-  inexact: boolean;
-}
-
-export interface ROArrayAT {
-  kind: 'ROArrayAT';
-  elem_t: FlowType;
-}
-
-// TupleElement definition
-export interface TupleElement {
-  name: string | null;
-  t: FlowType;
-  polarity: Polarity;
-  optional: boolean;
-}
-
-// Flags definition
-export interface Flags {
-  obj_kind: ObjKind;
-}
-
-// Property types
-export type Property =
-  | FieldProperty
-  | GetProperty
-  | SetProperty
-  | GetSetProperty
-  | MethodProperty;
-
-export interface FieldProperty {
-  kind: 'Field';
-  type: FlowType;
-  polarity: Polarity;
-}
-
-export interface GetProperty {
-  kind: 'Get';
-  type: FlowType;
-}
-
-export interface SetProperty {
-  kind: 'Set';
-  type: FlowType;
-}
-
-export interface GetSetProperty {
-  kind: 'GetSet';
-  get_type: FlowType;
-  set_type: FlowType;
-}
-
-export interface MethodProperty {
-  kind: 'Method';
-  type: FlowType;
-}
-
-// PropertyMap definition
-export interface PropertyMap {
-  [key: string]: Property; // For other properties in the map
-}
-
-// ObjType definition
-export interface ObjTypeObj {
-  flags: Flags;
-  props: PropertyMap;
-  proto_t: FlowType;
-  call_t: number | null;
-}
-
-// FunType definition
-export interface FunTypeObj {
-  this_t: {
-    type: FlowType;
-    status: ThisStatus;
-  };
-  params: Array<{
-    name: string | null;
-    type: FlowType;
-  }>;
-  rest_param: null | {
-    name: string | null;
-    type: FlowType;
-  };
-  return_t: FlowType;
-  type_guard: null | {
-    inferred: boolean;
-    param_name: string;
-    type_guard: FlowType;
-    one_sided: boolean;
-  };
-  effect: Effect;
-}
-
-// ThisStatus types
-export type ThisStatus =
-  | {kind: 'This_Method'; unbound: boolean}
-  | {kind: 'This_Function'};
-
-// Effect types
-export type Effect =
-  | {kind: 'HookDecl'; id: string}
-  | {kind: 'HookAnnot'}
-  | {kind: 'ArbitraryEffect'}
-  | {kind: 'AnyEffect'};
-
-// Destructor types
-export type Destructor =
-  | NonMaybeTypeDestructor
-  | PropertyTypeDestructor
-  | ElementTypeDestructor
-  | OptionalIndexedAccessNonMaybeTypeDestructor
-  | OptionalIndexedAccessResultTypeDestructor
-  | ExactTypeDestructor
-  | ReadOnlyTypeDestructor
-  | PartialTypeDestructor
-  | RequiredTypeDestructor
-  | SpreadTypeDestructor
-  | SpreadTupleTypeDestructor
-  | RestTypeDestructor
-  | ValuesTypeDestructor
-  | ConditionalTypeDestructor
-  | TypeMapDestructor
-  | ReactElementPropsTypeDestructor
-  | ReactElementConfigTypeDestructor
-  | ReactCheckComponentConfigDestructor
-  | ReactDRODestructor
-  | MakeHooklikeDestructor
-  | MappedTypeDestructor
-  | EnumTypeDestructor;
-
-export interface NonMaybeTypeDestructor {
-  kind: 'NonMaybeType';
-}
-
-export interface PropertyTypeDestructor {
-  kind: 'PropertyType';
-  name: string;
-}
-
-export interface ElementTypeDestructor {
-  kind: 'ElementType';
-  index_type: FlowType;
-}
-
-export interface OptionalIndexedAccessNonMaybeTypeDestructor {
-  kind: 'OptionalIndexedAccessNonMaybeType';
-  index: OptionalIndexedAccessIndex;
-}
-
-export type OptionalIndexedAccessIndex =
-  | {kind: 'StrLitIndex'; name: string}
-  | {kind: 'TypeIndex'; type: FlowType};
-
-export interface OptionalIndexedAccessResultTypeDestructor {
-  kind: 'OptionalIndexedAccessResultType';
-}
-
-export interface ExactTypeDestructor {
-  kind: 'ExactType';
-}
-
-export interface ReadOnlyTypeDestructor {
-  kind: 'ReadOnlyType';
-}
-
-export interface PartialTypeDestructor {
-  kind: 'PartialType';
-}
-
-export interface RequiredTypeDestructor {
-  kind: 'RequiredType';
-}
-
-export interface SpreadTypeDestructor {
-  kind: 'SpreadType';
-  target: SpreadTarget;
-  operands: Array<SpreadOperand>;
-  operand_slice: Slice | null;
-}
-
-export type SpreadTarget =
-  | {kind: 'Value'; make_seal: 'Sealed' | 'Frozen' | 'As_Const'}
-  | {kind: 'Annot'; make_exact: boolean};
-
-export type SpreadOperand = {kind: 'Type'; type: FlowType} | Slice;
-
-export interface Slice {
-  kind: 'Slice';
-  prop_map: PropertyMap;
-  generics: Array<string>;
-  dict: DictType | null;
-  reachable_targs: Array<{
-    type: FlowType;
-    polarity: Polarity;
-  }>;
-}
-
-export interface SpreadTupleTypeDestructor {
-  kind: 'SpreadTupleType';
-  inexact: boolean;
-  resolved_rev: string;
-  unresolved: string;
-}
-
-export interface RestTypeDestructor {
-  kind: 'RestType';
-  merge_mode: RestMergeMode;
-  type: FlowType;
-}
-
-export type RestMergeMode =
-  | {kind: 'SpreadReversal'}
-  | {kind: 'ReactConfigMerge'; polarity: Polarity}
-  | {kind: 'Omit'};
-
-export interface ValuesTypeDestructor {
-  kind: 'ValuesType';
-}
-
-export interface ConditionalTypeDestructor {
-  kind: 'ConditionalType';
-  distributive_tparam_name: string | null;
-  infer_tparams: string;
-  extends_t: FlowType;
-  true_t: FlowType;
-  false_t: FlowType;
-}
-
-export interface TypeMapDestructor {
-  kind: 'ObjectKeyMirror';
-}
-
-export interface ReactElementPropsTypeDestructor {
-  kind: 'ReactElementPropsType';
-}
-
-export interface ReactElementConfigTypeDestructor {
-  kind: 'ReactElementConfigType';
-}
-
-export interface ReactCheckComponentConfigDestructor {
-  kind: 'ReactCheckComponentConfig';
-  props: {
-    [key: string]: Property;
-  };
-}
-
-export interface ReactDRODestructor {
-  kind: 'ReactDRO';
-  dro_type:
-    | 'HookReturn'
-    | 'HookArg'
-    | 'Props'
-    | 'ImmutableAnnot'
-    | 'DebugAnnot';
-}
-
-export interface MakeHooklikeDestructor {
-  kind: 'MakeHooklike';
-}
-
-export interface MappedTypeDestructor {
-  kind: 'MappedType';
-  homomorphic: Homomorphic;
-  distributive_tparam_name: string | null;
-  property_type: FlowType;
-  mapped_type_flags: {
-    variance: Polarity;
-    optional: 'MakeOptional' | 'RemoveOptional' | 'KeepOptionality';
-  };
-}
-
-export type Homomorphic =
-  | {kind: 'Homomorphic'}
-  | {kind: 'Unspecialized'}
-  | {kind: 'SemiHomomorphic'; type: FlowType};
-
-export interface EnumTypeDestructor {
-  kind: 'EnumType';
-}
-
-// Union of all possible Flow types
-export type FlowType =
-  | OpenType
-  | DefType
-  | EvalType
-  | GenericType
-  | ThisInstanceType
-  | ThisTypeAppType
-  | TypeAppType
-  | FunProtoType
-  | ObjProtoType
-  | NullProtoType
-  | FunProtoBindType
-  | IntersectionType
-  | UnionType
-  | MaybeType
-  | OptionalType
-  | KeysType
-  | AnnotType
-  | OpaqueType
-  | NamespaceType
-  | AnyType
-  | StrUtilType;

compiler/packages/babel-plugin-react-compiler/src/Flood/TypeErrors.ts

@@ -1,138 +0,0 @@
-import {CompilerError, SourceLocation} from '..';
-import {
-  ConcreteType,
-  printConcrete,
-  printType,
-  StructuralValue,
-  Type,
-  VariableId,
-} from './Types';
-
-export function unsupportedLanguageFeature(
-  desc: string,
-  loc: SourceLocation,
-): never {
-  CompilerError.throwInvalidJS({
-    reason: `Typedchecker does not currently support language feature: ${desc}`,
-    loc,
-  });
-}
-
-export type UnificationError =
-  | {
-      kind: 'TypeUnification';
-      left: ConcreteType<Type>;
-      right: ConcreteType<Type>;
-    }
-  | {
-      kind: 'StructuralUnification';
-      left: StructuralValue;
-      right: ConcreteType<Type>;
-    };
-
-function printUnificationError(err: UnificationError): string {
-  if (err.kind === 'TypeUnification') {
-    return `${printConcrete(err.left, printType)} is incompatible with ${printConcrete(err.right, printType)}`;
-  } else {
-    return `structural ${err.left.kind} is incompatible with ${printConcrete(err.right, printType)}`;
-  }
-}
-
-export function raiseUnificationErrors(
-  errs: null | Array<UnificationError>,
-  loc: SourceLocation,
-): void {
-  if (errs != null) {
-    if (errs.length === 0) {
-      CompilerError.invariant(false, {
-        reason: 'Should not have array of zero errors',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc,
-            message: null,
-          },
-        ],
-      });
-    } else if (errs.length === 1) {
-      CompilerError.throwInvalidJS({
-        reason: `Unable to unify types because ${printUnificationError(errs[0])}`,
-        loc,
-      });
-    } else {
-      const messages = errs
-        .map(err => `\t* ${printUnificationError(err)}`)
-        .join('\n');
-      CompilerError.throwInvalidJS({
-        reason: `Unable to unify types because:\n${messages}`,
-        loc,
-      });
-    }
-  }
-}
-
-export function unresolvableTypeVariable(
-  id: VariableId,
-  loc: SourceLocation,
-): never {
-  CompilerError.throwInvalidJS({
-    reason: `Unable to resolve free variable ${id} to a concrete type`,
-    loc,
-  });
-}
-
-export function cannotAddVoid(explicit: boolean, loc: SourceLocation): never {
-  if (explicit) {
-    CompilerError.throwInvalidJS({
-      reason: `Undefined is not a valid operand of \`+\``,
-      loc,
-    });
-  } else {
-    CompilerError.throwInvalidJS({
-      reason: `Value may be undefined, which is not a valid operand of \`+\``,
-      loc,
-    });
-  }
-}
-
-export function unsupportedTypeAnnotation(
-  desc: string,
-  loc: SourceLocation,
-): never {
-  CompilerError.throwInvalidJS({
-    reason: `Typedchecker does not currently support type annotation: ${desc}`,
-    loc,
-  });
-}
-
-export function checkTypeArgumentArity(
-  desc: string,
-  expected: number,
-  actual: number,
-  loc: SourceLocation,
-): void {
-  if (expected !== actual) {
-    CompilerError.throwInvalidJS({
-      reason: `Expected ${desc} to have ${expected} type parameters, got ${actual}`,
-      loc,
-    });
-  }
-}
-
-export function notAFunction(desc: string, loc: SourceLocation): void {
-  CompilerError.throwInvalidJS({
-    reason: `Cannot call ${desc} because it is not a function`,
-    loc,
-  });
-}
-
-export function notAPolymorphicFunction(
-  desc: string,
-  loc: SourceLocation,
-): void {
-  CompilerError.throwInvalidJS({
-    reason: `Cannot call ${desc} with type arguments because it is not a polymorphic function`,
-    loc,
-  });
-}

compiler/packages/babel-plugin-react-compiler/src/Flood/TypeUtils.ts

@@ -1,312 +0,0 @@
-import {GeneratedSource} from '../HIR';
-import {assertExhaustive} from '../Utils/utils';
-import {unsupportedLanguageFeature} from './TypeErrors';
-import {
-  ConcreteType,
-  ResolvedType,
-  TypeParameter,
-  TypeParameterId,
-  DEBUG,
-  printConcrete,
-  printType,
-} from './Types';
-
-export function substitute(
-  type: ConcreteType<ResolvedType>,
-  typeParameters: Array<TypeParameter<ResolvedType>>,
-  typeArguments: Array<ResolvedType>,
-): ResolvedType {
-  const substMap = new Map<TypeParameterId, ResolvedType>();
-  for (let i = 0; i < typeParameters.length; i++) {
-    // TODO: Length checks to make sure type params match up with args
-    const typeParameter = typeParameters[i];
-    const typeArgument = typeArguments[i];
-    substMap.set(typeParameter.id, typeArgument);
-  }
-  const substitutionFunction = (t: ResolvedType): ResolvedType => {
-    // TODO: We really want a stateful mapper or visitor here so that we can model nested polymorphic types
-    if (t.type.kind === 'Generic' && substMap.has(t.type.id)) {
-      const substitutedType = substMap.get(t.type.id)!;
-      return substitutedType;
-    }
-
-    return {
-      kind: 'Concrete',
-      type: mapType(substitutionFunction, t.type),
-      platform: t.platform,
-    };
-  };
-
-  const substituted = mapType(substitutionFunction, type);
-
-  if (DEBUG) {
-    let substs = '';
-    for (let i = 0; i < typeParameters.length; i++) {
-      const typeParameter = typeParameters[i];
-      const typeArgument = typeArguments[i];
-      substs += `[${typeParameter.name}${typeParameter.id} := ${printType(typeArgument)}]`;
-    }
-    console.log(
-      `${printConcrete(type, printType)}${substs} = ${printConcrete(substituted, printType)}`,
-    );
-  }
-
-  return {kind: 'Concrete', type: substituted, platform: /* TODO */ 'shared'};
-}
-
-export function mapType<T, U>(
-  f: (t: T) => U,
-  type: ConcreteType<T>,
-): ConcreteType<U> {
-  switch (type.kind) {
-    case 'Mixed':
-    case 'Number':
-    case 'String':
-    case 'Boolean':
-    case 'Void':
-      return type;
-
-    case 'Nullable':
-      return {
-        kind: 'Nullable',
-        type: f(type.type),
-      };
-
-    case 'Array':
-      return {
-        kind: 'Array',
-        element: f(type.element),
-      };
-
-    case 'Set':
-      return {
-        kind: 'Set',
-        element: f(type.element),
-      };
-
-    case 'Map':
-      return {
-        kind: 'Map',
-        key: f(type.key),
-        value: f(type.value),
-      };
-
-    case 'Function':
-      return {
-        kind: 'Function',
-        typeParameters:
-          type.typeParameters?.map(param => ({
-            id: param.id,
-            name: param.name,
-            bound: f(param.bound),
-          })) ?? null,
-        params: type.params.map(f),
-        returnType: f(type.returnType),
-      };
-
-    case 'Component': {
-      return {
-        kind: 'Component',
-        children: type.children != null ? f(type.children) : null,
-        props: new Map([...type.props.entries()].map(([k, v]) => [k, f(v)])),
-      };
-    }
-
-    case 'Generic':
-      return {
-        kind: 'Generic',
-        id: type.id,
-        bound: f(type.bound),
-      };
-
-    case 'Object':
-      return type;
-
-    case 'Tuple':
-      return {
-        kind: 'Tuple',
-        id: type.id,
-        members: type.members.map(f),
-      };
-
-    case 'Structural':
-      return type;
-
-    case 'Enum':
-    case 'Union':
-    case 'Instance':
-      unsupportedLanguageFeature(type.kind, GeneratedSource);
-
-    default:
-      assertExhaustive(type, 'Unknown type kind');
-  }
-}
-
-export function diff<R, T>(
-  a: ConcreteType<T>,
-  b: ConcreteType<T>,
-  onChild: (a: T, b: T) => R,
-  onChildMismatch: (child: R, cur: R) => R,
-  onMismatch: (a: ConcreteType<T>, b: ConcreteType<T>, cur: R) => R,
-  init: R,
-): R {
-  let errors = init;
-
-  // Check if kinds match
-  if (a.kind !== b.kind) {
-    errors = onMismatch(a, b, errors);
-    return errors;
-  }
-
-  // Based on kind, check other properties
-  switch (a.kind) {
-    case 'Mixed':
-    case 'Number':
-    case 'String':
-    case 'Boolean':
-    case 'Void':
-      // Simple types, no further checks needed
-      break;
-
-    case 'Nullable':
-      // Check the nested type
-      errors = onChildMismatch(onChild(a.type, (b as typeof a).type), errors);
-      break;
-
-    case 'Array':
-    case 'Set':
-      // Check the element type
-      errors = onChildMismatch(
-        onChild(a.element, (b as typeof a).element),
-        errors,
-      );
-      break;
-
-    case 'Map':
-      // Check both key and value types
-      errors = onChildMismatch(onChild(a.key, (b as typeof a).key), errors);
-      errors = onChildMismatch(onChild(a.value, (b as typeof a).value), errors);
-      break;
-
-    case 'Function': {
-      const bFunc = b as typeof a;
-
-      // Check type parameters
-      if ((a.typeParameters == null) !== (bFunc.typeParameters == null)) {
-        errors = onMismatch(a, b, errors);
-      }
-
-      if (a.typeParameters != null && bFunc.typeParameters != null) {
-        if (a.typeParameters.length !== bFunc.typeParameters.length) {
-          errors = onMismatch(a, b, errors);
-        }
-
-        // Type parameters are just numbers, so we can compare them directly
-        for (let i = 0; i < a.typeParameters.length; i++) {
-          if (a.typeParameters[i] !== bFunc.typeParameters[i]) {
-            errors = onMismatch(a, b, errors);
-          }
-        }
-      }
-
-      // Check parameters
-      if (a.params.length !== bFunc.params.length) {
-        errors = onMismatch(a, b, errors);
-      }
-
-      for (let i = 0; i < a.params.length; i++) {
-        errors = onChildMismatch(onChild(a.params[i], bFunc.params[i]), errors);
-      }
-
-      // Check return type
-      errors = onChildMismatch(onChild(a.returnType, bFunc.returnType), errors);
-      break;
-    }
-
-    case 'Component': {
-      const bComp = b as typeof a;
-
-      // Check children
-      if (a.children !== bComp.children) {
-        errors = onMismatch(a, b, errors);
-      }
-
-      // Check props
-      if (a.props.size !== bComp.props.size) {
-        errors = onMismatch(a, b, errors);
-      }
-
-      for (const [k, v] of a.props) {
-        const bProp = bComp.props.get(k);
-        if (bProp == null) {
-          errors = onMismatch(a, b, errors);
-        } else {
-          errors = onChildMismatch(onChild(v, bProp), errors);
-        }
-      }
-
-      break;
-    }
-
-    case 'Generic': {
-      // Check that the type parameter IDs match
-      if (a.id !== (b as typeof a).id) {
-        errors = onMismatch(a, b, errors);
-      }
-      break;
-    }
-    case 'Structural': {
-      const bStruct = b as typeof a;
-
-      // Check that the structural IDs match
-      if (a.id !== bStruct.id) {
-        errors = onMismatch(a, b, errors);
-      }
-      break;
-    }
-    case 'Object': {
-      const bNom = b as typeof a;
-
-      // Check that the nominal IDs match
-      if (a.id !== bNom.id) {
-        errors = onMismatch(a, b, errors);
-      }
-      break;
-    }
-
-    case 'Tuple': {
-      const bTuple = b as typeof a;
-
-      // Check that the tuple IDs match
-      if (a.id !== bTuple.id) {
-        errors = onMismatch(a, b, errors);
-      }
-      for (let i = 0; i < a.members.length; i++) {
-        errors = onChildMismatch(
-          onChild(a.members[i], bTuple.members[i]),
-          errors,
-        );
-      }
-
-      break;
-    }
-
-    case 'Enum':
-    case 'Instance':
-    case 'Union': {
-      unsupportedLanguageFeature(a.kind, GeneratedSource);
-    }
-
-    default:
-      assertExhaustive(a, 'Unknown type kind');
-  }
-
-  return errors;
-}
-
-export function filterOptional(t: ResolvedType): ResolvedType {
-  if (t.kind === 'Concrete' && t.type.kind === 'Nullable') {
-    return t.type.type;
-  }
-  return t;
-}

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

@@ -38,13 +38,7 @@ export function assertConsistentIdentifiers(fn: HIRFunction): void {
       CompilerError.invariant(instr.lvalue.identifier.name === null, {
         reason: `Expected all lvalues to be temporaries`,
         description: `Found named lvalue \`${instr.lvalue.identifier.name}\``,
-        details: [
-          {
-            kind: 'error',
-            loc: instr.lvalue.loc,
-            message: null,
-          },
-        ],
+        loc: instr.lvalue.loc,
         suggestions: null,
       });
       CompilerError.invariant(!assignments.has(instr.lvalue.identifier.id), {
@@ -52,13 +46,7 @@ export function assertConsistentIdentifiers(fn: HIRFunction): void {
         description: `Found duplicate assignment of '${printPlace(
           instr.lvalue,
         )}'`,
-        details: [
-          {
-            kind: 'error',
-            loc: instr.lvalue.loc,
-            message: null,
-          },
-        ],
+        loc: instr.lvalue.loc,
         suggestions: null,
       });
       assignments.add(instr.lvalue.identifier.id);
@@ -89,13 +77,7 @@ function validate(
     CompilerError.invariant(identifier === previous, {
       reason: `Duplicate identifier object`,
       description: `Found duplicate identifier object for id ${identifier.id}`,
-      details: [
-        {
-          kind: 'error',
-          loc: loc ?? GeneratedSource,
-          message: null,
-        },
-      ],
+      loc: loc ?? GeneratedSource,
       suggestions: null,
     });
   }

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

@@ -18,13 +18,7 @@ export function assertTerminalSuccessorsExist(fn: HIRFunction): void {
         description: `Block bb${successor} does not exist for terminal '${printTerminal(
           block.terminal,
         )}'`,
-        details: [
-          {
-            kind: 'error',
-            loc: (block.terminal as any).loc ?? GeneratedSource,
-            message: null,
-          },
-        ],
+        loc: (block.terminal as any).loc ?? GeneratedSource,
         suggestions: null,
       });
       return successor;
@@ -39,26 +33,14 @@ export function assertTerminalPredsExist(fn: HIRFunction): void {
       CompilerError.invariant(predBlock != null, {
         reason: 'Expected predecessor block to exist',
         description: `Block ${block.id} references non-existent ${pred}`,
-        details: [
-          {
-            kind: 'error',
-            loc: GeneratedSource,
-            message: null,
-          },
-        ],
+        loc: GeneratedSource,
       });
       CompilerError.invariant(
         [...eachTerminalSuccessor(predBlock.terminal)].includes(block.id),
         {
           reason: 'Terminal successor does not reference correct predecessor',
           description: `Block bb${block.id} has bb${predBlock.id} as a predecessor, but bb${predBlock.id}'s successors do not include bb${block.id}`,
-          details: [
-            {
-              kind: 'error',
-              loc: GeneratedSource,
-              message: null,
-            },
-          ],
+          loc: GeneratedSource,
         },
       );
     }

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

@@ -131,13 +131,7 @@ export function recursivelyTraverseItems<T, TContext>(
       CompilerError.invariant(disjoint || nested, {
         reason: 'Invalid nesting in program blocks or scopes',
         description: `Items overlap but are not nested: ${maybeParentRange.start}:${maybeParentRange.end}(${currRange.start}:${currRange.end})`,
-        details: [
-          {
-            kind: 'error',
-            loc: GeneratedSource,
-            message: null,
-          },
-        ],
+        loc: GeneratedSource,
       });
       if (disjoint) {
         exit(maybeParent, context);

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

@@ -5,14 +5,13 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {HIRFunction, MutableRange, Place} from './HIR';
+import invariant from 'invariant';
+import {HIRFunction, Identifier, MutableRange} from './HIR';
 import {
   eachInstructionLValue,
   eachInstructionOperand,
   eachTerminalOperand,
 } from './visitors';
-import {CompilerError} from '..';
-import {printPlace} from './PrintHIR';
 
 /*
  * Checks that all mutable ranges in the function are well-formed, with
@@ -21,49 +20,38 @@ import {printPlace} from './PrintHIR';
 export function assertValidMutableRanges(fn: HIRFunction): void {
   for (const [, block] of fn.body.blocks) {
     for (const phi of block.phis) {
-      visit(phi.place, `phi for block bb${block.id}`);
-      for (const [pred, operand] of phi.operands) {
-        visit(operand, `phi predecessor bb${pred} for block bb${block.id}`);
+      visitIdentifier(phi.place.identifier);
+      for (const [, operand] of phi.operands) {
+        visitIdentifier(operand.identifier);
       }
     }
     for (const instr of block.instructions) {
       for (const operand of eachInstructionLValue(instr)) {
-        visit(operand, `instruction [${instr.id}]`);
+        visitIdentifier(operand.identifier);
       }
       for (const operand of eachInstructionOperand(instr)) {
-        visit(operand, `instruction [${instr.id}]`);
+        visitIdentifier(operand.identifier);
       }
     }
     for (const operand of eachTerminalOperand(block.terminal)) {
-      visit(operand, `terminal [${block.terminal.id}]`);
+      visitIdentifier(operand.identifier);
     }
   }
 }
 
-function visit(place: Place, description: string): void {
-  validateMutableRange(place, place.identifier.mutableRange, description);
-  if (place.identifier.scope !== null) {
-    validateMutableRange(place, place.identifier.scope.range, description);
+function visitIdentifier(identifier: Identifier): void {
+  validateMutableRange(identifier.mutableRange);
+  if (identifier.scope !== null) {
+    validateMutableRange(identifier.scope.range);
   }
 }
 
-function validateMutableRange(
-  place: Place,
-  range: MutableRange,
-  description: string,
-): void {
-  CompilerError.invariant(
-    (range.start === 0 && range.end === 0) || range.end > range.start,
-    {
-      reason: `Invalid mutable range: [${range.start}:${range.end}]`,
-      description: `${printPlace(place)} in ${description}`,
-      details: [
-        {
-          kind: 'error',
-          loc: place.loc,
-          message: null,
-        },
-      ],
-    },
+function validateMutableRange(mutableRange: MutableRange): void {
+  invariant(
+    (mutableRange.start === 0 && mutableRange.end === 0) ||
+      mutableRange.end > mutableRange.start,
+    'Identifier scope mutableRange was invalid: [%s:%s]',
+    mutableRange.start,
+    mutableRange.end,
   );
 }

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

@@ -234,14 +234,7 @@ function pushEndScopeTerminal(
   const fallthroughId = context.fallthroughs.get(scope.id);
   CompilerError.invariant(fallthroughId != null, {
     reason: 'Expected scope to exist',
-    description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: GeneratedSource,
-        message: null,
-      },
-    ],
+    loc: GeneratedSource,
   });
   context.rewrites.push({
     kind: 'EndScope',

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

@@ -269,14 +269,7 @@ class PropertyPathRegistry {
       CompilerError.invariant(reactive === rootNode.fullPath.reactive, {
         reason:
           '[HoistablePropertyLoads] Found inconsistencies in `reactive` flag when deduping identifier reads within the same scope',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: identifier.loc,
-            message: null,
-          },
-        ],
+        loc: identifier.loc,
       });
     }
     return rootNode;
@@ -454,32 +447,6 @@ 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);
-            }
-          }
-        }
       }
     }
 
@@ -531,14 +498,7 @@ function propagateNonNull(
     if (node == null) {
       CompilerError.invariant(false, {
         reason: `Bad node ${nodeId}, kind: ${direction}`,
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: GeneratedSource,
-            message: null,
-          },
-        ],
+        loc: GeneratedSource,
       });
     }
     const neighbors = Array.from(
@@ -610,14 +570,7 @@ function propagateNonNull(
     CompilerError.invariant(i++ < 100, {
       reason:
         '[CollectHoistablePropertyLoads] fixed point iteration did not terminate after 100 loops',
-      description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: GeneratedSource,
-          message: null,
-        },
-      ],
+      loc: GeneratedSource,
     });
 
     changed = false;
@@ -649,13 +602,7 @@ export function assertNonNull<T extends NonNullable<U>, U>(
   CompilerError.invariant(value != null, {
     reason: 'Unexpected null',
     description: source != null ? `(from ${source})` : null,
-    details: [
-      {
-        kind: 'error',
-        loc: GeneratedSource,
-        message: null,
-      },
-    ],
+    loc: GeneratedSource,
   });
   return value;
 }

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

@@ -186,13 +186,7 @@ function matchOptionalTestBlock(
         reason:
           '[OptionalChainDeps] Inconsistent optional chaining property load',
         description: `Test=${printIdentifier(terminal.test.identifier)} PropertyLoad base=${printIdentifier(propertyLoad.value.object.identifier)}`,
-        details: [
-          {
-            kind: 'error',
-            loc: propertyLoad.loc,
-            message: null,
-          },
-        ],
+        loc: propertyLoad.loc,
       },
     );
 
@@ -200,14 +194,7 @@ function matchOptionalTestBlock(
       storeLocal.value.identifier.id === propertyLoad.lvalue.identifier.id,
       {
         reason: '[OptionalChainDeps] Unexpected storeLocal',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: propertyLoad.loc,
-            message: null,
-          },
-        ],
+        loc: propertyLoad.loc,
       },
     );
     if (
@@ -224,14 +211,7 @@ function matchOptionalTestBlock(
         alternate.instructions[1].value.kind === 'StoreLocal',
       {
         reason: 'Unexpected alternate structure',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: terminal.loc,
-            message: null,
-          },
-        ],
+        loc: terminal.loc,
       },
     );
 
@@ -267,14 +247,7 @@ function traverseOptionalBlock(
   if (maybeTest.terminal.kind === 'branch') {
     CompilerError.invariant(optional.terminal.optional, {
       reason: '[OptionalChainDeps] Expect base case to be always optional',
-      description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: optional.terminal.loc,
-          message: null,
-        },
-      ],
+      loc: optional.terminal.loc,
     });
     /**
      * Optional base expressions are currently within value blocks which cannot
@@ -312,14 +285,7 @@ function traverseOptionalBlock(
         maybeTest.instructions.at(-1)!.lvalue.identifier.id,
       {
         reason: '[OptionalChainDeps] Unexpected test expression',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: maybeTest.terminal.loc,
-            message: null,
-          },
-        ],
+        loc: maybeTest.terminal.loc,
       },
     );
     baseObject = {
@@ -408,14 +374,7 @@ function traverseOptionalBlock(
       reason:
         '[OptionalChainDeps] Unexpected instructions an inner optional block. ' +
         'This indicates that the compiler may be incorrectly concatenating two unrelated optional chains',
-      description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: optional.terminal.loc,
-          message: null,
-        },
-      ],
+      loc: optional.terminal.loc,
     });
   }
   const matchConsequentResult = matchOptionalTestBlock(test, context.blocks);
@@ -428,13 +387,7 @@ function traverseOptionalBlock(
     {
       reason: '[OptionalChainDeps] Unexpected optional goto-fallthrough',
       description: `${matchConsequentResult.consequentGoto} != ${optional.terminal.fallthrough}`,
-      details: [
-        {
-          kind: 'error',
-          loc: optional.terminal.loc,
-          message: null,
-        },
-      ],
+      loc: optional.terminal.loc,
     },
   );
   const load = {

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

@@ -24,14 +24,7 @@ export function computeUnconditionalBlocks(fn: HIRFunction): Set<BlockId> {
     CompilerError.invariant(!unconditionalBlocks.has(current), {
       reason:
         'Internal error: non-terminating loop in ComputeUnconditionalBlocks',
-      description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
+      loc: null,
       suggestions: null,
     });
     unconditionalBlocks.add(current);

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

@@ -1,109 +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 {Effect, ValueKind} from '..';
-import {TypeConfig} from './TypeSchema';
-
-/**
- * Libraries developed before we officially documented the [Rules of React](https://react.dev/reference/rules)
- * implement APIs which cannot be memoized safely, either via manual or automatic memoization.
- *
- * Any non-hook API that is designed to be called during render (not events/effects) should be safe to memoize:
- *
- * ```js
- * function Component() {
- *   const {someFunction} = useLibrary();
- *   // it should always be safe to memoize functions like this
- *  const result = useMemo(() => someFunction(), [someFunction]);
- * }
- * ```
- *
- * However, some APIs implement "interior mutability" — mutating values rather than copying into a new value
- * and setting state with the new value. Such functions (`someFunction()` in the example) could return different
- * values even though the function itself is the same object. This breaks memoization, since React relies on
- * the outer object (or function) changing if part of its value has changed.
- *
- * Given that we didn't have the Rules of React precisely documented prior to the introduction of React compiler,
- * it's understandable that some libraries accidentally shipped APIs that break this rule. However, developers
- * can easily run into pitfalls with these APIs. They may manually memoize them, which can break their app. Or
- * they may try using React Compiler, and think that the compiler has broken their code.
- *
- * To help ensure that developers can successfully use the compiler with existing code, this file teaches the
- * compiler about specific APIs that are known to be incompatible with memoization. We've tried to be as precise
- * as possible.
- *
- * The React team is open to collaborating with library authors to help develop compatible versions of these APIs,
- * and we have already reached out to the teams who own any API listed here to ensure they are aware of the issue.
- */
-export function defaultModuleTypeProvider(
-  moduleName: string,
-): TypeConfig | null {
-  switch (moduleName) {
-    case 'react-hook-form': {
-      return {
-        kind: 'object',
-        properties: {
-          useForm: {
-            kind: 'hook',
-            returnType: {
-              kind: 'object',
-              properties: {
-                // Only the `watch()` function returned by react-hook-form's `useForm()` API is incompatible
-                watch: {
-                  kind: 'function',
-                  positionalParams: [],
-                  restParam: Effect.Read,
-                  calleeEffect: Effect.Read,
-                  returnType: {kind: 'type', name: 'Any'},
-                  returnValueKind: ValueKind.Mutable,
-                  knownIncompatible: `React Hook Form's \`useForm()\` API returns a \`watch()\` function which cannot be memoized safely.`,
-                },
-              },
-            },
-          },
-        },
-      };
-    }
-    case '@tanstack/react-table': {
-      return {
-        kind: 'object',
-        properties: {
-          /*
-           * Many of the properties of `useReactTable()`'s return value are incompatible, so we mark the entire hook
-           * as incompatible
-           */
-          useReactTable: {
-            kind: 'hook',
-            positionalParams: [],
-            restParam: Effect.Read,
-            returnType: {kind: 'type', name: 'Any'},
-            knownIncompatible: `TanStack Table's \`useReactTable()\` API returns functions that cannot be memoized safely`,
-          },
-        },
-      };
-    }
-    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/DeriveMinimalDependenciesHIR.ts

@@ -54,14 +54,7 @@ export class ReactiveScopeDependencyTreeHIR {
           prevAccessType == null || prevAccessType === accessType,
           {
             reason: 'Conflicting access types',
-            description: null,
-            details: [
-              {
-                kind: 'error',
-                loc: GeneratedSource,
-                message: null,
-              },
-            ],
+            loc: GeneratedSource,
           },
         );
         let nextNode = currNode.properties.get(path[i].property);
@@ -97,13 +90,7 @@ export class ReactiveScopeDependencyTreeHIR {
       CompilerError.invariant(reactive === rootNode.reactive, {
         reason: '[DeriveMinimalDependenciesHIR] Conflicting reactive root flag',
         description: `Identifier ${printIdentifier(identifier)}`,
-        details: [
-          {
-            kind: 'error',
-            loc: GeneratedSource,
-            message: null,
-          },
-        ],
+        loc: GeneratedSource,
       });
     }
     return rootNode;

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

@@ -89,13 +89,7 @@ export class Dominator<T> {
     CompilerError.invariant(dominator !== undefined, {
       reason: 'Unknown node',
       description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
+      loc: null,
       suggestions: null,
     });
     return dominator === id ? null : dominator;
@@ -136,13 +130,7 @@ export class PostDominator<T> {
     CompilerError.invariant(dominator !== undefined, {
       reason: 'Unknown node',
       description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
+      loc: null,
       suggestions: null,
     });
     return dominator === id ? null : dominator;
@@ -187,13 +175,7 @@ function computeImmediateDominators<T>(graph: Graph<T>): Map<T, T> {
       CompilerError.invariant(newIdom !== null, {
         reason: `At least one predecessor must have been visited for block ${id}`,
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: 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';
@@ -49,8 +49,6 @@ import {
 } from './ObjectShape';
 import {Scope as BabelScope, NodePath} from '@babel/traverse';
 import {TypeSchema} from './TypeSchema';
-import {FlowTypeEnv} from '../Flood/Types';
-import {defaultModuleTypeProvider} from './DefaultModuleTypeProvider';
 
 export const ReactElementSymbolSchema = z.object({
   elementSymbol: z.union([
@@ -159,7 +157,7 @@ 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 +208,7 @@ 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
@@ -245,12 +243,6 @@ export const EnvironmentConfigSchema = z.object({
    */
   enableUseTypeAnnotations: z.boolean().default(false),
 
-  /**
-   * Allows specifying a function that can populate HIR with type information from
-   * Flow
-   */
-  flowTypeProvider: z.nullable(z.any()).default(null),
-
   /**
    * Enables inference of optional dependency chains. Without this flag
    * a property chain such as `props?.items?.foo` will infer as a dep on
@@ -261,8 +253,6 @@ export const EnvironmentConfigSchema = z.object({
 
   enableFire: z.boolean().default(false),
 
-  enableNameAnonymousFunctions: z.boolean().default(false),
-
   /**
    * Enables inference and auto-insertion of effect dependencies. Takes in an array of
    * configurable module and import pairs to allow for user-land experimentation. For example,
@@ -270,19 +260,21 @@ export const EnvironmentConfigSchema = z.object({
    *   {
    *     module: 'react',
    *     imported: 'useEffect',
-   *     autodepsIndex: 1,
+   *     numRequiredArgs: 1,
    *   },{
    *     module: 'MyExperimentalEffectHooks',
    *     imported: 'useExperimentalEffect',
-   *     autodepsIndex: 2,
+   *     numRequiredArgs: 2,
    *   },
    * ]
    * would insert dependencies for calls of `useEffect` imported from `react` and calls of
    * useExperimentalEffect` from `MyExperimentalEffectHooks`.
    *
-   * `autodepsIndex` tells the compiler which index we expect the AUTODEPS to appear in.
-   *  With the configuration above, we'd insert dependencies for `useEffect` if it has two
-   *  arguments, and the second is AUTODEPS.
+   * `numRequiredArgs` tells the compiler the amount of arguments required to append a dependency
+   *  array to the end of the call. With the configuration above, we'd insert dependencies for
+   *  `useEffect` if it is only given a single argument and it would be appended to the argument list.
+   *
+   * numRequiredArgs must always be greater than 0, otherwise there is no function to analyze for dependencies
    *
    * Still experimental.
    */
@@ -291,7 +283,7 @@ export const EnvironmentConfigSchema = z.object({
       z.array(
         z.object({
           function: ExternalFunctionSchema,
-          autodepsIndex: z.number().min(1, 'autodepsIndex must be > 0'),
+          numRequiredArgs: z.number().min(1, 'numRequiredArgs must be > 0'),
         }),
       ),
     )
@@ -323,16 +315,10 @@ export const EnvironmentConfigSchema = z.object({
   validateNoSetStateInRender: z.boolean().default(true),
 
   /**
-   * Validates that setState is not called synchronously within an effect (useEffect and friends).
+   * Validates that setState is not called directly within a passive effect (useEffect).
    * Scheduling a setState (with an event listener, subscription, etc) is valid.
    */
-  validateNoSetStateInEffects: z.boolean().default(false),
-
-  /**
-   * Validates that effects are not used to calculate derived data which could instead be computed
-   * during render.
-   */
-  validateNoDerivedComputationsInEffects: z.boolean().default(false),
+  validateNoSetStateInPassiveEffects: z.boolean().default(false),
 
   /**
    * Validates against creating JSX within a try block and recommends using an error boundary
@@ -619,14 +605,7 @@ export const EnvironmentConfigSchema = z.object({
    *
    * Here the variables `ref` and `myRef` will be typed as Refs.
    */
-  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),
+  enableTreatRefLikeIdentifiersAsRefs: z.boolean().default(false),
 
   /*
    * If specified a value, the compiler lowers any calls to `useContext` to use
@@ -649,31 +628,6 @@ export const EnvironmentConfigSchema = z.object({
    * ```
    */
   lowerContextAccess: ExternalFunctionSchema.nullable().default(null),
-
-  /**
-   * If enabled, will validate useMemos that don't return any values:
-   *
-   * Valid:
-   *   useMemo(() => foo, [foo]);
-   *   useMemo(() => { return foo }, [foo]);
-   * Invalid:
-   *   useMemo(() => { ... }, [...]);
-   */
-  validateNoVoidUseMemo: z.boolean().default(true),
-
-  /**
-   * Validates that Components/Hooks are always defined at module level. This prevents scope
-   * reference errors that occur when the compiler attempts to optimize the nested component/hook
-   * 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>;
@@ -723,8 +677,6 @@ export class Environment {
   #hoistedIdentifiers: Set<t.Identifier>;
   parentFunction: NodePath<t.Function>;
 
-  #flowTypeEnvironment: FlowTypeEnv | null;
-
   constructor(
     scope: BabelScope,
     fnType: ReactFunctionType,
@@ -766,13 +718,7 @@ export class Environment {
       CompilerError.invariant(!this.#globals.has(hookName), {
         reason: `[Globals] Found existing definition in global registry for custom hook ${hookName}`,
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       });
       this.#globals.set(
@@ -799,40 +745,6 @@ export class Environment {
     this.parentFunction = parentFunction;
     this.#contextIdentifiers = contextIdentifiers;
     this.#hoistedIdentifiers = new Set();
-
-    if (config.flowTypeProvider != null) {
-      this.#flowTypeEnvironment = new FlowTypeEnv();
-      CompilerError.invariant(code != null, {
-        reason:
-          'Expected Environment to be initialized with source code when a Flow type provider is specified',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
-      });
-      this.#flowTypeEnvironment.init(this, code);
-    } else {
-      this.#flowTypeEnvironment = null;
-    }
-  }
-
-  get typeContext(): FlowTypeEnv {
-    CompilerError.invariant(this.#flowTypeEnvironment != null, {
-      reason: 'Flow type environment not initialized',
-      description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
-    });
-    return this.#flowTypeEnvironment;
   }
 
   get isInferredMemoEnabled(): boolean {
@@ -897,22 +809,10 @@ export class Environment {
   #resolveModuleType(moduleName: string, loc: SourceLocation): Global | null {
     let moduleType = this.#moduleTypes.get(moduleName);
     if (moduleType === undefined) {
-      /*
-       * NOTE: Zod doesn't work when specifying a function as a default, so we have to
-       * fallback to the default value here
-       */
-      const moduleTypeProvider =
-        this.config.moduleTypeProvider ?? defaultModuleTypeProvider;
-      if (moduleTypeProvider == null) {
+      if (this.config.moduleTypeProvider == null) {
         return null;
       }
-      if (typeof moduleTypeProvider !== 'function') {
-        CompilerError.throwInvalidConfig({
-          reason: `Expected a function for \`moduleTypeProvider\``,
-          loc,
-        });
-      }
-      const unparsedModuleConfig = moduleTypeProvider(moduleName);
+      const unparsedModuleConfig = this.config.moduleTypeProvider(moduleName);
       if (unparsedModuleConfig != null) {
         const parsedModuleConfig = TypeSchema.safeParse(unparsedModuleConfig);
         if (!parsedModuleConfig.success) {
@@ -1086,13 +986,7 @@ export class Environment {
       CompilerError.invariant(shape !== undefined, {
         reason: `[HIR] Forget internal error: cannot resolve shape ${shapeId}`,
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       });
       return shape.properties.get('*') ?? null;
@@ -1117,13 +1011,7 @@ export class Environment {
       CompilerError.invariant(shape !== undefined, {
         reason: `[HIR] Forget internal error: cannot resolve shape ${shapeId}`,
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       });
       if (typeof property === 'string') {
@@ -1148,13 +1036,7 @@ export class Environment {
       CompilerError.invariant(shape !== undefined, {
         reason: `[HIR] Forget internal error: cannot resolve shape ${shapeId}`,
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       });
       return shape.functionType;

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

@@ -184,13 +184,7 @@ function handleAssignment(
           CompilerError.invariant(valuePath.isLVal(), {
             reason: `[FindContextIdentifiers] Expected object property value to be an LVal, got: ${valuePath.type}`,
             description: null,
-            details: [
-              {
-                kind: 'error',
-                loc: valuePath.node.loc ?? GeneratedSource,
-                message: null,
-              },
-            ],
+            loc: valuePath.node.loc ?? GeneratedSource,
             suggestions: null,
           });
           handleAssignment(currentFn, identifiers, valuePath);
@@ -198,13 +192,7 @@ function handleAssignment(
           CompilerError.invariant(property.isRestElement(), {
             reason: `[FindContextIdentifiers] Invalid assumptions for babel types.`,
             description: null,
-            details: [
-              {
-                kind: 'error',
-                loc: property.node.loc ?? GeneratedSource,
-                message: null,
-              },
-            ],
+            loc: property.node.loc ?? GeneratedSource,
             suggestions: null,
           });
           handleAssignment(currentFn, identifiers, property);

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

@@ -9,7 +9,6 @@ import {Effect, ValueKind, ValueReason} from './HIR';
 import {
   BUILTIN_SHAPES,
   BuiltInArrayId,
-  BuiltInAutodepsId,
   BuiltInFireFunctionId,
   BuiltInFireId,
   BuiltInMapId,
@@ -18,7 +17,6 @@ import {
   BuiltInSetId,
   BuiltInUseActionStateId,
   BuiltInUseContextHookId,
-  BuiltInUseEffectEventId,
   BuiltInUseEffectHookId,
   BuiltInUseInsertionEffectHookId,
   BuiltInUseLayoutEffectHookId,
@@ -29,7 +27,6 @@ import {
   BuiltInUseTransitionId,
   BuiltInWeakMapId,
   BuiltInWeakSetId,
-  BuiltinEffectEventId,
   ReanimatedSharedValueId,
   ShapeRegistry,
   addFunction,
@@ -114,99 +111,6 @@ const TYPED_GLOBALS: Array<[string, BuiltInType]> = [
           returnValueKind: ValueKind.Mutable,
         }),
       ],
-      [
-        'entries',
-        addFunction(DEFAULT_SHAPES, [], {
-          positionalParams: [Effect.Capture],
-          restParam: null,
-          returnType: {kind: 'Object', shapeId: BuiltInArrayId},
-          calleeEffect: Effect.Read,
-          returnValueKind: ValueKind.Mutable,
-          aliasing: {
-            receiver: '@receiver',
-            params: ['@object'],
-            rest: null,
-            returns: '@returns',
-            temporaries: [],
-            effects: [
-              {
-                kind: 'Create',
-                into: '@returns',
-                reason: ValueReason.KnownReturnSignature,
-                value: ValueKind.Mutable,
-              },
-              // Object values are captured into the return
-              {
-                kind: 'Capture',
-                from: '@object',
-                into: '@returns',
-              },
-            ],
-          },
-        }),
-      ],
-      [
-        'keys',
-        addFunction(DEFAULT_SHAPES, [], {
-          positionalParams: [Effect.Read],
-          restParam: null,
-          returnType: {kind: 'Object', shapeId: BuiltInArrayId},
-          calleeEffect: Effect.Read,
-          returnValueKind: ValueKind.Mutable,
-          aliasing: {
-            receiver: '@receiver',
-            params: ['@object'],
-            rest: null,
-            returns: '@returns',
-            temporaries: [],
-            effects: [
-              {
-                kind: 'Create',
-                into: '@returns',
-                reason: ValueReason.KnownReturnSignature,
-                value: ValueKind.Mutable,
-              },
-              // Only keys are captured, and keys are immutable
-              {
-                kind: 'ImmutableCapture',
-                from: '@object',
-                into: '@returns',
-              },
-            ],
-          },
-        }),
-      ],
-      [
-        'values',
-        addFunction(DEFAULT_SHAPES, [], {
-          positionalParams: [Effect.Capture],
-          restParam: null,
-          returnType: {kind: 'Object', shapeId: BuiltInArrayId},
-          calleeEffect: Effect.Read,
-          returnValueKind: ValueKind.Mutable,
-          aliasing: {
-            receiver: '@receiver',
-            params: ['@object'],
-            rest: null,
-            returns: '@returns',
-            temporaries: [],
-            effects: [
-              {
-                kind: 'Create',
-                into: '@returns',
-                reason: ValueReason.KnownReturnSignature,
-                value: ValueKind.Mutable,
-              },
-              // Object values are captured into the return
-              {
-                kind: 'Capture',
-                from: '@object',
-                into: '@returns',
-              },
-            ],
-          },
-        }),
-      ],
     ]),
   ],
   [
@@ -738,41 +642,6 @@ const REACT_APIS: Array<[string, BuiltInType]> = [
         calleeEffect: Effect.Read,
         hookKind: 'useEffect',
         returnValueKind: ValueKind.Frozen,
-        aliasing: {
-          receiver: '@receiver',
-          params: [],
-          rest: '@rest',
-          returns: '@returns',
-          temporaries: ['@effect'],
-          effects: [
-            // Freezes the function and deps
-            {
-              kind: 'Freeze',
-              value: '@rest',
-              reason: ValueReason.Effect,
-            },
-            // Internally creates an effect object that captures the function and deps
-            {
-              kind: 'Create',
-              into: '@effect',
-              value: ValueKind.Frozen,
-              reason: ValueReason.KnownReturnSignature,
-            },
-            // The effect stores the function and dependencies
-            {
-              kind: 'Capture',
-              from: '@rest',
-              into: '@effect',
-            },
-            // Returns undefined
-            {
-              kind: 'Create',
-              into: '@returns',
-              value: ValueKind.Primitive,
-              reason: ValueReason.KnownReturnSignature,
-            },
-          ],
-        },
       },
       BuiltInUseEffectHookId,
     ),
@@ -853,28 +722,6 @@ const REACT_APIS: Array<[string, BuiltInType]> = [
       BuiltInFireId,
     ),
   ],
-  [
-    'useEffectEvent',
-    addHook(
-      DEFAULT_SHAPES,
-      {
-        positionalParams: [],
-        restParam: Effect.Freeze,
-        returnType: {
-          kind: 'Function',
-          return: {kind: 'Poly'},
-          shapeId: BuiltinEffectEventId,
-          isConstructor: false,
-        },
-        calleeEffect: Effect.Read,
-        hookKind: 'useEffectEvent',
-        // Frozen because it should not mutate any locally-bound values
-        returnValueKind: ValueKind.Frozen,
-      },
-      BuiltInUseEffectEventId,
-    ),
-  ],
-  ['AUTODEPS', addObject(DEFAULT_SHAPES, BuiltInAutodepsId, [])],
 ];
 
 TYPED_GLOBALS.push(
@@ -1000,8 +847,6 @@ export function installTypeConfig(
         noAlias: typeConfig.noAlias === true,
         mutableOnlyIfOperandsAreMutable:
           typeConfig.mutableOnlyIfOperandsAreMutable === true,
-        aliasing: typeConfig.aliasing,
-        knownIncompatible: typeConfig.knownIncompatible ?? null,
       });
     }
     case 'hook': {
@@ -1019,8 +864,6 @@ export function installTypeConfig(
         ),
         returnValueKind: typeConfig.returnValueKind ?? ValueKind.Frozen,
         noAlias: typeConfig.noAlias === true,
-        aliasing: typeConfig.aliasing,
-        knownIncompatible: typeConfig.knownIncompatible ?? null,
       });
     }
     case 'object': {

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

@@ -7,19 +7,12 @@
 
 import {BindingKind} from '@babel/traverse';
 import * as t from '@babel/types';
-import {
-  CompilerDiagnostic,
-  CompilerError,
-  ErrorCategory,
-} from '../CompilerError';
+import {CompilerError, CompilerErrorDetailOptions} from '../CompilerError';
 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 type {AliasingEffect} from '../Inference/AliasingEffects';
-import {isReservedWord} from '../Utils/Keyword';
-import {Err, Ok, Result} from '../Utils/Result';
+import {z} from 'zod';
 
 /*
  * *******************************************************************************************
@@ -58,8 +51,7 @@ export type SourceLocation = t.SourceLocation | typeof GeneratedSource;
  */
 export type ReactiveFunction = {
   loc: SourceLocation;
-  id: ValidIdentifierName | null;
-  nameHint: string | null;
+  id: string | null;
   params: Array<Place | SpreadPattern>;
   generator: boolean;
   async: boolean;
@@ -108,7 +100,6 @@ export type ReactiveInstruction = {
   id: InstructionId;
   lvalue: Place | null;
   value: ReactiveValue;
-  effects?: Array<AliasingEffect> | null; // TODO make non-optional
   loc: SourceLocation;
 };
 
@@ -281,21 +272,36 @@ export type ReactiveTryTerminal = {
 // A function lowered to HIR form, ie where its body is lowered to an HIR control-flow graph
 export type HIRFunction = {
   loc: SourceLocation;
-  id: ValidIdentifierName | null;
-  nameHint: string | null;
+  id: string | null;
   fnType: ReactFunctionType;
   env: Environment;
   params: Array<Place | SpreadPattern>;
   returnTypeAnnotation: t.FlowType | t.TSType | null;
-  returns: Place;
+  returnType: Type;
   context: Array<Place>;
+  effects: Array<FunctionEffect> | null;
   body: HIR;
   generator: boolean;
   async: boolean;
   directives: Array<string>;
-  aliasingEffects: Array<AliasingEffect> | null;
 };
 
+export type FunctionEffect =
+  | {
+      kind: 'GlobalMutation';
+      error: CompilerErrorDetailOptions;
+    }
+  | {
+      kind: 'ReactMutation';
+      error: CompilerErrorDetailOptions;
+    }
+  | {
+      kind: 'ContextMutation';
+      places: ReadonlySet<Place>;
+      effect: Effect;
+      loc: SourceLocation;
+    };
+
 /*
  * Each reactive scope may have its own control-flow, so the instructions form
  * a control-flow graph. The graph comprises a set of basic blocks which reference
@@ -437,25 +443,12 @@ export type ThrowTerminal = {
 };
 export type Case = {test: Place | null; block: BlockId};
 
-export type ReturnVariant = 'Void' | 'Implicit' | 'Explicit';
 export type ReturnTerminal = {
   kind: 'return';
-  /**
-   * Void:
-   *   () => { ... }
-   *   function() { ... }
-   * Implicit (ArrowFunctionExpression only):
-   *   () => foo
-   * Explicit:
-   *   () => { return ... }
-   *   function () { return ... }
-   */
-  returnVariant: ReturnVariant;
   loc: SourceLocation;
   value: Place;
   id: InstructionId;
   fallthrough?: never;
-  effects: Array<AliasingEffect> | null;
 };
 
 export type GotoTerminal = {
@@ -616,7 +609,6 @@ export type MaybeThrowTerminal = {
   id: InstructionId;
   loc: SourceLocation;
   fallthrough?: never;
-  effects: Array<AliasingEffect> | null;
 };
 
 export type ReactiveScopeTerminal = {
@@ -653,14 +645,12 @@ export type Instruction = {
   lvalue: Place;
   value: InstructionValue;
   loc: SourceLocation;
-  effects: Array<AliasingEffect> | null;
 };
 
 export type TInstruction<T extends InstructionValue> = {
   id: InstructionId;
   lvalue: Place;
   value: T;
-  effects: Array<AliasingEffect> | null;
   loc: SourceLocation;
 };
 
@@ -1130,8 +1120,7 @@ export type JsxAttribute =
 
 export type FunctionExpression = {
   kind: 'FunctionExpression';
-  name: ValidIdentifierName | null;
-  nameHint: string | null;
+  name: string | null;
   loweredFunc: LoweredFunction;
   type:
     | 'ArrowFunctionExpression'
@@ -1306,52 +1295,22 @@ export function forkTemporaryIdentifier(
   };
 }
 
-export function validateIdentifierName(
-  name: string,
-): Result<ValidatedIdentifier, CompilerError> {
-  if (isReservedWord(name)) {
-    const error = new CompilerError();
-    error.pushDiagnostic(
-      CompilerDiagnostic.create({
-        category: ErrorCategory.Syntax,
-        reason: 'Expected a non-reserved identifier name',
-        description: `\`${name}\` is a reserved word in JavaScript and cannot be used as an identifier name`,
-        suggestions: null,
-      }).withDetails({
-        kind: 'error',
-        loc: GeneratedSource,
-        message: 'reserved word',
-      }),
-    );
-    return Err(error);
-  } else if (!t.isValidIdentifier(name)) {
-    const error = new CompilerError();
-    error.pushDiagnostic(
-      CompilerDiagnostic.create({
-        category: ErrorCategory.Syntax,
-        reason: `Expected a valid identifier name`,
-        description: `\`${name}\` is not a valid JavaScript identifier`,
-        suggestions: null,
-      }).withDetails({
-        kind: 'error',
-        loc: GeneratedSource,
-        message: 'reserved word',
-      }),
-    );
-  }
-  return Ok({
-    kind: 'named',
-    value: name as ValidIdentifierName,
-  });
-}
-
 /**
  * Creates a valid identifier name. This should *not* be used for synthesizing
  * identifier names: only call this method for identifier names that appear in the
  * original source code.
  */
 export function makeIdentifierName(name: string): ValidatedIdentifier {
-  return validateIdentifierName(name).unwrap();
+  CompilerError.invariant(t.isValidIdentifier(name), {
+    reason: `Expected a valid identifier name`,
+    loc: GeneratedSource,
+    description: `\`${name}\` is not a valid JavaScript identifier`,
+    suggestions: null,
+  });
+  return {
+    kind: 'named',
+    value: name as ValidIdentifierName,
+  };
 }
 
 /**
@@ -1363,14 +1322,8 @@ export function makeIdentifierName(name: string): ValidatedIdentifier {
 export function promoteTemporary(identifier: Identifier): void {
   CompilerError.invariant(identifier.name === null, {
     reason: `Expected a temporary (unnamed) identifier`,
+    loc: GeneratedSource,
     description: `Identifier already has a name, \`${identifier.name}\``,
-    details: [
-      {
-        kind: 'error',
-        loc: GeneratedSource,
-        message: null,
-      },
-    ],
     suggestions: null,
   });
   identifier.name = {
@@ -1393,14 +1346,8 @@ export function isPromotedTemporary(name: string): boolean {
 export function promoteTemporaryJsxTag(identifier: Identifier): void {
   CompilerError.invariant(identifier.name === null, {
     reason: `Expected a temporary (unnamed) identifier`,
+    loc: GeneratedSource,
     description: `Identifier already has a name, \`${identifier.name}\``,
-    details: [
-      {
-        kind: 'error',
-        loc: GeneratedSource,
-        message: null,
-      },
-    ],
     suggestions: null,
   });
   identifier.name = {
@@ -1433,21 +1380,6 @@ export enum ValueReason {
    */
   JsxCaptured = 'jsx-captured',
 
-  /**
-   * Argument to a hook
-   */
-  HookCaptured = 'hook-captured',
-
-  /**
-   * Return value of a hook
-   */
-  HookReturn = 'hook-return',
-
-  /**
-   * Passed to an effect
-   */
-  Effect = 'effect',
-
   /**
    * Return value of a function with known frozen return value, e.g. `useState`.
    */
@@ -1498,20 +1430,6 @@ export const ValueKindSchema = z.enum([
   ValueKind.Context,
 ]);
 
-export const ValueReasonSchema = z.enum([
-  ValueReason.Context,
-  ValueReason.Effect,
-  ValueReason.Global,
-  ValueReason.HookCaptured,
-  ValueReason.HookReturn,
-  ValueReason.JsxCaptured,
-  ValueReason.KnownReturnSignature,
-  ValueReason.Other,
-  ValueReason.ReactiveFunctionArgument,
-  ValueReason.ReducerState,
-  ValueReason.State,
-]);
-
 // The effect with which a value is modified.
 export enum Effect {
   // Default value: not allowed after lifetime inference
@@ -1568,13 +1486,7 @@ export function isMutableEffect(
       CompilerError.invariant(false, {
         reason: 'Unexpected unknown effect',
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: location,
-            message: null,
-          },
-        ],
+        loc: location,
         suggestions: null,
       });
     }
@@ -1707,13 +1619,7 @@ export function makeBlockId(id: number): BlockId {
   CompilerError.invariant(id >= 0 && Number.isInteger(id), {
     reason: 'Expected block id to be a non-negative integer',
     description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: null,
-        message: null,
-      },
-    ],
+    loc: null,
     suggestions: null,
   });
   return id as BlockId;
@@ -1730,13 +1636,7 @@ export function makeScopeId(id: number): ScopeId {
   CompilerError.invariant(id >= 0 && Number.isInteger(id), {
     reason: 'Expected block id to be a non-negative integer',
     description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: null,
-        message: null,
-      },
-    ],
+    loc: null,
     suggestions: null,
   });
   return id as ScopeId;
@@ -1753,13 +1653,7 @@ export function makeIdentifierId(id: number): IdentifierId {
   CompilerError.invariant(id >= 0 && Number.isInteger(id), {
     reason: 'Expected identifier id to be a non-negative integer',
     description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: null,
-        message: null,
-      },
-    ],
+    loc: null,
     suggestions: null,
   });
   return id as IdentifierId;
@@ -1776,13 +1670,7 @@ export function makeDeclarationId(id: number): DeclarationId {
   CompilerError.invariant(id >= 0 && Number.isInteger(id), {
     reason: 'Expected declaration id to be a non-negative integer',
     description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: null,
-        message: null,
-      },
-    ],
+    loc: null,
     suggestions: null,
   });
   return id as DeclarationId;
@@ -1799,13 +1687,7 @@ export function makeInstructionId(id: number): InstructionId {
   CompilerError.invariant(id >= 0 && Number.isInteger(id), {
     reason: 'Expected instruction id to be a non-negative integer',
     description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: null,
-        message: null,
-      },
-    ],
+    loc: null,
     suggestions: null,
   });
   return id as InstructionId;
@@ -1851,10 +1733,6 @@ export function isUseStateType(id: Identifier): boolean {
   return id.type.kind === 'Object' && id.type.shapeId === 'BuiltInUseState';
 }
 
-export function isJsxType(type: Type): boolean {
-  return type.kind === 'Object' && type.shapeId === 'BuiltInJsx';
-}
-
 export function isRefOrRefValue(id: Identifier): boolean {
   return isUseRefType(id) || isRefValueType(id);
 }
@@ -1907,13 +1785,6 @@ export function isFireFunctionType(id: Identifier): boolean {
   );
 }
 
-export function isEffectEventFunctionType(id: Identifier): boolean {
-  return (
-    id.type.kind === 'Function' &&
-    id.type.shapeId === 'BuiltInEffectEventFunction'
-  );
-}
-
 export function isStableType(id: Identifier): boolean {
   return (
     isSetStateType(id) ||

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

@@ -7,7 +7,7 @@
 
 import {Binding, NodePath} from '@babel/traverse';
 import * as t from '@babel/types';
-import {CompilerError, ErrorCategory} from '../CompilerError';
+import {CompilerError} from '../CompilerError';
 import {Environment} from './Environment';
 import {
   BasicBlock,
@@ -106,7 +106,7 @@ export default class HIRBuilder {
   #current: WipBlock;
   #entry: BlockId;
   #scopes: Array<Scope> = [];
-  #context: Map<t.Identifier, SourceLocation>;
+  #context: Array<t.Identifier>;
   #bindings: Bindings;
   #env: Environment;
   #exceptionHandlerStack: Array<BlockId> = [];
@@ -121,7 +121,7 @@ export default class HIRBuilder {
     return this.#env.nextIdentifierId;
   }
 
-  get context(): Map<t.Identifier, SourceLocation> {
+  get context(): Array<t.Identifier> {
     return this.#context;
   }
 
@@ -137,13 +137,13 @@ export default class HIRBuilder {
     env: Environment,
     options?: {
       bindings?: Bindings | null;
-      context?: Map<t.Identifier, SourceLocation>;
+      context?: Array<t.Identifier>;
       entryBlockKind?: BlockKind;
     },
   ) {
     this.#env = env;
     this.#bindings = options?.bindings ?? new Map();
-    this.#context = options?.context ?? new Map();
+    this.#context = options?.context ?? [];
     this.#entry = makeBlockId(env.nextBlockId);
     this.#current = newBlock(this.#entry, options?.entryBlockKind ?? 'block');
   }
@@ -165,7 +165,6 @@ export default class HIRBuilder {
           handler: exceptionHandler,
           id: makeInstructionId(0),
           loc: instruction.loc,
-          effects: null,
         },
         continuationBlock,
       );
@@ -308,33 +307,9 @@ export default class HIRBuilder {
 
   resolveBinding(node: t.Identifier): Identifier {
     if (node.name === 'fbt') {
-      CompilerError.throwDiagnostic({
-        category: ErrorCategory.Todo,
-        reason: 'Support local variables named `fbt`',
-        description:
-          'Local variables named `fbt` may conflict with the fbt plugin and are not yet supported',
-        details: [
-          {
-            kind: 'error',
-            message: 'Rename to avoid conflict with fbt plugin',
-            loc: node.loc ?? GeneratedSource,
-          },
-        ],
-      });
-    }
-    if (node.name === 'this') {
-      CompilerError.throwDiagnostic({
-        category: ErrorCategory.UnsupportedSyntax,
-        reason: '`this` is not supported syntax',
-        description:
-          'React Compiler does not support compiling functions that use `this`',
-        details: [
-          {
-            kind: 'error',
-            message: '`this` was used here',
-            loc: node.loc ?? GeneratedSource,
-          },
-        ],
+      CompilerError.throwTodo({
+        reason: 'Support local variables named "fbt"',
+        loc: node.loc ?? null,
       });
     }
     const originalName = node.name;
@@ -507,13 +482,7 @@ export default class HIRBuilder {
       {
         reason: 'Mismatched label',
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       },
     );
@@ -536,13 +505,7 @@ export default class HIRBuilder {
       {
         reason: 'Mismatched label',
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       },
     );
@@ -578,13 +541,7 @@ export default class HIRBuilder {
       {
         reason: 'Mismatched loops',
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       },
     );
@@ -609,13 +566,7 @@ export default class HIRBuilder {
     CompilerError.invariant(false, {
       reason: 'Expected a loop or switch to be in scope',
       description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
+      loc: null,
       suggestions: null,
     });
   }
@@ -636,13 +587,7 @@ export default class HIRBuilder {
         CompilerError.invariant(false, {
           reason: 'Continue may only refer to a labeled loop',
           description: null,
-          details: [
-            {
-              kind: 'error',
-              loc: null,
-              message: null,
-            },
-          ],
+          loc: null,
           suggestions: null,
         });
       }
@@ -650,13 +595,7 @@ export default class HIRBuilder {
     CompilerError.invariant(false, {
       reason: 'Expected a loop to be in scope',
       description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
+      loc: null,
       suggestions: null,
     });
   }
@@ -679,13 +618,7 @@ function _shrink(func: HIR): void {
     CompilerError.invariant(block != null, {
       reason: `expected block ${blockId} to exist`,
       description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
+      loc: null,
       suggestions: null,
     });
     target = getTargetIfIndirection(block);
@@ -817,13 +750,7 @@ function getReversePostorderedBlocks(func: HIR): HIR['blocks'] {
     CompilerError.invariant(block != null, {
       reason: '[HIRBuilder] Unexpected null block',
       description: `expected block ${blockId} to exist`,
-      details: [
-        {
-          kind: 'error',
-          loc: GeneratedSource,
-          message: null,
-        },
-      ],
+      loc: GeneratedSource,
     });
     const successors = [...eachTerminalSuccessor(block.terminal)].reverse();
     const fallthrough = terminalFallthrough(block.terminal);
@@ -879,13 +806,7 @@ export function markInstructionIds(func: HIR): void {
       CompilerError.invariant(!visited.has(instr), {
         reason: `${printInstruction(instr)} already visited!`,
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: instr.loc,
-            message: null,
-          },
-        ],
+        loc: instr.loc,
         suggestions: null,
       });
       visited.add(instr);
@@ -908,13 +829,7 @@ export function markPredecessors(func: HIR): void {
     CompilerError.invariant(block != null, {
       reason: 'unexpected missing block',
       description: `block ${blockId}`,
-      details: [
-        {
-          kind: 'error',
-          loc: GeneratedSource,
-          message: null,
-        },
-      ],
+      loc: GeneratedSource,
     });
     if (prevBlock) {
       block.preds.add(prevBlock.id);

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

@@ -12,7 +12,6 @@ import {
   GeneratedSource,
   HIRFunction,
   Instruction,
-  Place,
 } from './HIR';
 import {markPredecessors} from './HIRBuilder';
 import {terminalFallthrough, terminalHasFallthrough} from './visitors';
@@ -61,13 +60,7 @@ export function mergeConsecutiveBlocks(fn: HIRFunction): void {
     CompilerError.invariant(predecessor !== undefined, {
       reason: `Expected predecessor ${predecessorId} to exist`,
       description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
+      loc: null,
       suggestions: null,
     });
     if (predecessor.terminal.kind !== 'goto' || predecessor.kind !== 'block') {
@@ -83,32 +76,24 @@ export function mergeConsecutiveBlocks(fn: HIRFunction): void {
       CompilerError.invariant(phi.operands.size === 1, {
         reason: `Found a block with a single predecessor but where a phi has multiple (${phi.operands.size}) operands`,
         description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: null,
-            message: null,
-          },
-        ],
+        loc: null,
         suggestions: null,
       });
       const operand = Array.from(phi.operands.values())[0]!;
-      const lvalue: Place = {
-        kind: 'Identifier',
-        identifier: phi.place.identifier,
-        effect: Effect.ConditionallyMutate,
-        reactive: false,
-        loc: GeneratedSource,
-      };
       const instr: Instruction = {
         id: predecessor.terminal.id,
-        lvalue: {...lvalue},
+        lvalue: {
+          kind: 'Identifier',
+          identifier: phi.place.identifier,
+          effect: Effect.ConditionallyMutate,
+          reactive: false,
+          loc: GeneratedSource,
+        },
         value: {
           kind: 'LoadLocal',
           place: {...operand},
           loc: GeneratedSource,
         },
-        effects: [{kind: 'Alias', from: {...operand}, into: {...lvalue}}],
         loc: GeneratedSource,
       };
       predecessor.instructions.push(instr);
@@ -119,17 +104,6 @@ export function mergeConsecutiveBlocks(fn: HIRFunction): void {
     merged.merge(block.id, predecessorId);
     fn.body.blocks.delete(block.id);
   }
-  for (const [, block] of fn.body.blocks) {
-    for (const phi of block.phis) {
-      for (const [predecessorId, operand] of phi.operands) {
-        const mapped = merged.get(predecessorId);
-        if (mapped !== predecessorId) {
-          phi.operands.delete(predecessorId);
-          phi.operands.set(mapped, operand);
-        }
-      }
-    }
-  }
   markPredecessors(fn.body);
   for (const [, {terminal}] of fn.body.blocks) {
     if (terminalHasFallthrough(terminal)) {

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

@@ -6,30 +6,14 @@
  */
 
 import {CompilerError} from '../CompilerError';
-import {AliasingEffect, AliasingSignature} from '../Inference/AliasingEffects';
-import {assertExhaustive} from '../Utils/utils';
-import {
-  Effect,
-  GeneratedSource,
-  Hole,
-  makeDeclarationId,
-  makeIdentifierId,
-  makeInstructionId,
-  Place,
-  SourceLocation,
-  SpreadPattern,
-  ValueKind,
-  ValueReason,
-} from './HIR';
+import {Effect, ValueKind, ValueReason} from './HIR';
 import {
   BuiltInType,
   FunctionType,
-  makeType,
   ObjectType,
   PolyType,
   PrimitiveType,
 } from './Types';
-import {AliasingEffectConfig, AliasingSignatureConfig} from './TypeSchema';
 
 /*
  * This file exports types and defaults for JavaScript object shapes. These are
@@ -58,20 +42,13 @@ function createAnonId(): string {
 export function addFunction(
   registry: ShapeRegistry,
   properties: Iterable<[string, BuiltInType | PolyType]>,
-  fn: Omit<FunctionSignature, 'hookKind' | 'aliasing'> & {
-    aliasing?: AliasingSignatureConfig | null | undefined;
-  },
+  fn: Omit<FunctionSignature, 'hookKind'>,
   id: string | null = null,
   isConstructor: boolean = false,
 ): FunctionType {
   const shapeId = id ?? createAnonId();
-  const aliasing =
-    fn.aliasing != null
-      ? parseAliasingSignatureConfig(fn.aliasing, '<builtin>', GeneratedSource)
-      : null;
   addShape(registry, shapeId, properties, {
     ...fn,
-    aliasing,
     hookKind: null,
   });
   return {
@@ -89,18 +66,11 @@ export function addFunction(
  */
 export function addHook(
   registry: ShapeRegistry,
-  fn: Omit<FunctionSignature, 'aliasing'> & {
-    hookKind: HookKind;
-    aliasing?: AliasingSignatureConfig | null | undefined;
-  },
+  fn: FunctionSignature & {hookKind: HookKind},
   id: string | null = null,
 ): FunctionType {
   const shapeId = id ?? createAnonId();
-  const aliasing =
-    fn.aliasing != null
-      ? parseAliasingSignatureConfig(fn.aliasing, '<builtin>', GeneratedSource)
-      : null;
-  addShape(registry, shapeId, [], {...fn, aliasing});
+  addShape(registry, shapeId, [], fn);
   return {
     kind: 'Function',
     return: fn.returnType,
@@ -109,142 +79,6 @@ export function addHook(
   };
 }
 
-function parseAliasingSignatureConfig(
-  typeConfig: AliasingSignatureConfig,
-  moduleName: string,
-  loc: SourceLocation,
-): AliasingSignature {
-  const lifetimes = new Map<string, Place>();
-  function define(temp: string): Place {
-    CompilerError.invariant(!lifetimes.has(temp), {
-      reason: `Invalid type configuration for module`,
-      description: `Expected aliasing signature to have unique names for receiver, params, rest, returns, and temporaries in module '${moduleName}'`,
-      details: [
-        {
-          kind: 'error',
-          loc,
-          message: null,
-        },
-      ],
-    });
-    const place = signatureArgument(lifetimes.size);
-    lifetimes.set(temp, place);
-    return place;
-  }
-  function lookup(temp: string): Place {
-    const place = lifetimes.get(temp);
-    CompilerError.invariant(place != null, {
-      reason: `Invalid type configuration for module`,
-      description: `Expected aliasing signature effects to reference known names from receiver/params/rest/returns/temporaries, but '${temp}' is not a known name in '${moduleName}'`,
-      details: [
-        {
-          kind: 'error',
-          loc,
-          message: null,
-        },
-      ],
-    });
-    return place;
-  }
-  const receiver = define(typeConfig.receiver);
-  const params = typeConfig.params.map(define);
-  const rest = typeConfig.rest != null ? define(typeConfig.rest) : null;
-  const returns = define(typeConfig.returns);
-  const temporaries = typeConfig.temporaries.map(define);
-  const effects = typeConfig.effects.map(
-    (effect: AliasingEffectConfig): AliasingEffect => {
-      switch (effect.kind) {
-        case 'ImmutableCapture':
-        case 'CreateFrom':
-        case 'Capture':
-        case 'Alias':
-        case 'Assign': {
-          const from = lookup(effect.from);
-          const into = lookup(effect.into);
-          return {
-            kind: effect.kind,
-            from,
-            into,
-          };
-        }
-        case 'Mutate':
-        case 'MutateTransitiveConditionally': {
-          const value = lookup(effect.value);
-          return {kind: effect.kind, value};
-        }
-        case 'Create': {
-          const into = lookup(effect.into);
-          return {
-            kind: 'Create',
-            into,
-            reason: effect.reason,
-            value: effect.value,
-          };
-        }
-        case 'Freeze': {
-          const value = lookup(effect.value);
-          return {
-            kind: 'Freeze',
-            value,
-            reason: effect.reason,
-          };
-        }
-        case 'Impure': {
-          const place = lookup(effect.place);
-          return {
-            kind: 'Impure',
-            place,
-            error: CompilerError.throwTodo({
-              reason: 'Support impure effect declarations',
-              loc: GeneratedSource,
-            }),
-          };
-        }
-        case 'Apply': {
-          const receiver = lookup(effect.receiver);
-          const fn = lookup(effect.function);
-          const args: Array<Place | SpreadPattern | Hole> = effect.args.map(
-            arg => {
-              if (typeof arg === 'string') {
-                return lookup(arg);
-              } else if (arg.kind === 'Spread') {
-                return {kind: 'Spread', place: lookup(arg.place)};
-              } else {
-                return arg;
-              }
-            },
-          );
-          const into = lookup(effect.into);
-          return {
-            kind: 'Apply',
-            receiver,
-            function: fn,
-            mutatesFunction: effect.mutatesFunction,
-            args,
-            into,
-            loc,
-            signature: null,
-          };
-        }
-        default: {
-          assertExhaustive(
-            effect,
-            `Unexpected effect kind '${(effect as any).kind}'`,
-          );
-        }
-      }
-    },
-  );
-  return {
-    receiver: receiver.identifier.id,
-    params: params.map(p => p.identifier.id),
-    rest: rest != null ? rest.identifier.id : null,
-    returns: returns.identifier.id,
-    temporaries,
-    effects,
-  };
-}
-
 /*
  * Add an object to an existing ShapeRegistry.
  *
@@ -277,13 +111,7 @@ function addShape(
   CompilerError.invariant(!registry.has(id), {
     reason: `[ObjectShape] Could not add shape to registry: name ${id} already exists.`,
     description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: null,
-        message: null,
-      },
-    ],
+    loc: null,
     suggestions: null,
   });
   registry.set(id, shape);
@@ -303,7 +131,6 @@ export type HookKind =
   | 'useCallback'
   | 'useTransition'
   | 'useImperativeHandle'
-  | 'useEffectEvent'
   | 'Custom';
 
 /*
@@ -350,11 +177,8 @@ export type FunctionSignature = {
   mutableOnlyIfOperandsAreMutable?: boolean;
 
   impure?: boolean;
-  knownIncompatible?: string | null | undefined;
 
   canonicalName?: string;
-
-  aliasing?: AliasingSignature | null | undefined;
 };
 
 /*
@@ -402,9 +226,6 @@ export const BuiltInUseTransitionId = 'BuiltInUseTransition';
 export const BuiltInStartTransitionId = 'BuiltInStartTransition';
 export const BuiltInFireId = 'BuiltInFire';
 export const BuiltInFireFunctionId = 'BuiltInFireFunction';
-export const BuiltInUseEffectEventId = 'BuiltInUseEffectEvent';
-export const BuiltinEffectEventId = 'BuiltInEffectEventFunction';
-export const BuiltInAutodepsId = 'BuiltInAutoDepsId';
 
 // See getReanimatedModuleType() in Globals.ts — this is part of supporting Reanimated's ref-like types
 export const ReanimatedSharedValueId = 'ReanimatedSharedValueId';
@@ -481,30 +302,6 @@ addObject(BUILTIN_SHAPES, BuiltInArrayId, [
       returnType: PRIMITIVE_TYPE,
       calleeEffect: Effect.Store,
       returnValueKind: ValueKind.Primitive,
-      aliasing: {
-        receiver: '@receiver',
-        params: [],
-        rest: '@rest',
-        returns: '@returns',
-        temporaries: [],
-        effects: [
-          // Push directly mutates the array itself
-          {kind: 'Mutate', value: '@receiver'},
-          // The arguments are captured into the array
-          {
-            kind: 'Capture',
-            from: '@rest',
-            into: '@receiver',
-          },
-          // Returns the new length, a primitive
-          {
-            kind: 'Create',
-            into: '@returns',
-            value: ValueKind.Primitive,
-            reason: ValueReason.KnownReturnSignature,
-          },
-        ],
-      },
     }),
   ],
   [
@@ -535,60 +332,6 @@ addObject(BUILTIN_SHAPES, BuiltInArrayId, [
       returnValueKind: ValueKind.Mutable,
       noAlias: true,
       mutableOnlyIfOperandsAreMutable: true,
-      aliasing: {
-        receiver: '@receiver',
-        params: ['@callback'],
-        rest: null,
-        returns: '@returns',
-        temporaries: [
-          // Temporary representing captured items of the receiver
-          '@item',
-          // Temporary representing the result of the callback
-          '@callbackReturn',
-          /*
-           * Undefined `this` arg to the callback. Note the signature does not
-           * support passing an explicit thisArg second param
-           */
-          '@thisArg',
-        ],
-        effects: [
-          // Map creates a new mutable array
-          {
-            kind: 'Create',
-            into: '@returns',
-            value: ValueKind.Mutable,
-            reason: ValueReason.KnownReturnSignature,
-          },
-          // The first arg to the callback is an item extracted from the receiver array
-          {
-            kind: 'CreateFrom',
-            from: '@receiver',
-            into: '@item',
-          },
-          // The undefined this for the callback
-          {
-            kind: 'Create',
-            into: '@thisArg',
-            value: ValueKind.Primitive,
-            reason: ValueReason.KnownReturnSignature,
-          },
-          // calls the callback, returning the result into a temporary
-          {
-            kind: 'Apply',
-            receiver: '@thisArg',
-            args: ['@item', {kind: 'Hole'}, '@receiver'],
-            function: '@callback',
-            into: '@callbackReturn',
-            mutatesFunction: false,
-          },
-          // captures the result of the callback into the return array
-          {
-            kind: 'Capture',
-            from: '@callbackReturn',
-            into: '@returns',
-          },
-        ],
-      },
     }),
   ],
   [
@@ -736,32 +479,6 @@ addObject(BUILTIN_SHAPES, BuiltInSetId, [
       calleeEffect: Effect.Store,
       // returnValueKind is technically dependent on the ValueKind of the set itself
       returnValueKind: ValueKind.Mutable,
-      aliasing: {
-        receiver: '@receiver',
-        params: [],
-        rest: '@rest',
-        returns: '@returns',
-        temporaries: [],
-        effects: [
-          // Set.add returns the receiver Set
-          {
-            kind: 'Assign',
-            from: '@receiver',
-            into: '@returns',
-          },
-          // Set.add mutates the set itself
-          {
-            kind: 'Mutate',
-            value: '@receiver',
-          },
-          // Captures the rest params into the set
-          {
-            kind: 'Capture',
-            from: '@rest',
-            into: '@receiver',
-          },
-        ],
-      },
     }),
   ],
   [
@@ -1231,21 +948,6 @@ addObject(BUILTIN_SHAPES, BuiltInRefValueId, [
   ['*', {kind: 'Object', shapeId: BuiltInRefValueId}],
 ]);
 
-addObject(BUILTIN_SHAPES, ReanimatedSharedValueId, []);
-
-addFunction(
-  BUILTIN_SHAPES,
-  [],
-  {
-    positionalParams: [],
-    restParam: Effect.ConditionallyMutate,
-    returnType: {kind: 'Poly'},
-    calleeEffect: Effect.ConditionallyMutate,
-    returnValueKind: ValueKind.Mutable,
-  },
-  BuiltinEffectEventId,
-);
-
 /**
  * MixedReadOnly =
  *   | primitive
@@ -1464,53 +1166,6 @@ export const DefaultNonmutatingHook = addHook(
     calleeEffect: Effect.Read,
     hookKind: 'Custom',
     returnValueKind: ValueKind.Frozen,
-    aliasing: {
-      receiver: '@receiver',
-      params: [],
-      rest: '@rest',
-      returns: '@returns',
-      temporaries: [],
-      effects: [
-        // Freeze the arguments
-        {
-          kind: 'Freeze',
-          value: '@rest',
-          reason: ValueReason.HookCaptured,
-        },
-        // Returns a frozen value
-        {
-          kind: 'Create',
-          into: '@returns',
-          value: ValueKind.Frozen,
-          reason: ValueReason.HookReturn,
-        },
-        // May alias any arguments into the return
-        {
-          kind: 'Alias',
-          from: '@rest',
-          into: '@returns',
-        },
-      ],
-    },
   },
   'DefaultNonmutatingHook',
 );
-
-export function signatureArgument(id: number): Place {
-  const place: Place = {
-    kind: 'Identifier',
-    effect: Effect.Unknown,
-    loc: GeneratedSource,
-    reactive: false,
-    identifier: {
-      declarationId: makeDeclarationId(id),
-      id: makeIdentifierId(id),
-      loc: GeneratedSource,
-      mutableRange: {start: makeInstructionId(0), end: makeInstructionId(0)},
-      name: null,
-      scope: null,
-      type: makeType(),
-    },
-  };
-  return place;
-}

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

@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import generate from '@babel/generator';
 import {CompilerError} from '../CompilerError';
 import {printReactiveScopeSummary} from '../ReactiveScopes/PrintReactiveFunction';
 import DisjointSet from '../Utils/DisjointSet';
@@ -34,7 +35,6 @@ import type {
   Type,
 } from './HIR';
 import {GotoVariant, InstructionKind} from './HIR';
-import {AliasingEffect, AliasingSignature} from '../Inference/AliasingEffects';
 
 export type Options = {
   indent: number;
@@ -53,11 +53,6 @@ export function printFunction(fn: HIRFunction): string {
   let definition = '';
   if (fn.id !== null) {
     definition += fn.id;
-  } else {
-    definition += '<<anonymous>>';
-  }
-  if (fn.nameHint != null) {
-    definition += ` ${fn.nameHint}`;
   }
   if (fn.params.length !== 0) {
     definition +=
@@ -72,13 +67,13 @@ export function printFunction(fn: HIRFunction): string {
         })
         .join(', ') +
       ')';
-  } else {
-    definition += '()';
   }
-  definition += `: ${printPlace(fn.returns)}`;
-  output.push(definition);
-  output.push(...fn.directives);
+  if (definition.length !== 0) {
+    output.push(definition);
+  }
+  output.push(printType(fn.returnType));
   output.push(printHIR(fn.body));
+  output.push(...fn.directives);
   return output.join('\n');
 }
 
@@ -156,10 +151,7 @@ export function printMixedHIR(
 
 export function printInstruction(instr: ReactiveInstruction): string {
   const id = `[${instr.id}]`;
-  let value = printInstructionValue(instr.value);
-  if (instr.effects != null) {
-    value += `\n    ${instr.effects.map(printAliasingEffect).join('\n    ')}`;
-  }
+  const value = printInstructionValue(instr.value);
 
   if (instr.lvalue !== null) {
     return `${id} ${printPlace(instr.lvalue)} = ${value}`;
@@ -218,12 +210,9 @@ export function printTerminal(terminal: Terminal): Array<string> | string {
       break;
     }
     case 'return': {
-      value = `[${terminal.id}] Return ${terminal.returnVariant}${
+      value = `[${terminal.id}] Return${
         terminal.value != null ? ' ' + printPlace(terminal.value) : ''
       }`;
-      if (terminal.effects != null) {
-        value += `\n    ${terminal.effects.map(printAliasingEffect).join('\n    ')}`;
-      }
       break;
     }
     case 'goto': {
@@ -292,9 +281,6 @@ export function printTerminal(terminal: Terminal): Array<string> | string {
     }
     case 'maybe-throw': {
       value = `[${terminal.id}] MaybeThrow continuation=bb${terminal.continuation} handler=bb${terminal.handler}`;
-      if (terminal.effects != null) {
-        value += `\n    ${terminal.effects.map(printAliasingEffect).join('\n    ')}`;
-      }
       break;
     }
     case 'scope': {
@@ -468,7 +454,7 @@ export function printInstructionValue(instrValue: ReactiveValue): string {
       break;
     }
     case 'UnsupportedNode': {
-      value = `UnsupportedNode ${instrValue.node.type}`;
+      value = `UnsupportedNode(${generate(instrValue.node).code})`;
       break;
     }
     case 'LoadLocal': {
@@ -557,11 +543,20 @@ export function printInstructionValue(instrValue: ReactiveValue): string {
       const context = instrValue.loweredFunc.func.context
         .map(dep => printPlace(dep))
         .join(',');
-      const aliasingEffects =
-        instrValue.loweredFunc.func.aliasingEffects
-          ?.map(printAliasingEffect)
-          ?.join(', ') ?? '';
-      value = `${kind} ${name} @context[${context}] @aliasingEffects=[${aliasingEffects}]\n${fn}`;
+      const effects =
+        instrValue.loweredFunc.func.effects
+          ?.map(effect => {
+            if (effect.kind === 'ContextMutation') {
+              return `ContextMutation places=[${[...effect.places]
+                .map(place => printPlace(place))
+                .join(', ')}] effect=${effect.effect}`;
+            } else {
+              return `GlobalMutation`;
+            }
+          })
+          .join(', ') ?? '';
+      const type = printType(instrValue.loweredFunc.func.returnType).trim();
+      value = `${kind} ${name} @context[${context}] @effects[${effects}]${type !== '' ? ` return${type}` : ''}:\n${fn}`;
       break;
     }
     case 'TaggedTemplateExpression': {
@@ -599,13 +594,7 @@ export function printInstructionValue(instrValue: ReactiveValue): string {
         {
           reason: 'Bad assumption about quasi length.',
           description: null,
-          details: [
-            {
-              kind: 'error',
-              loc: instrValue.loc,
-              message: null,
-            },
-          ],
+          loc: instrValue.loc,
           suggestions: null,
         },
       );
@@ -711,7 +700,7 @@ export function printInstructionValue(instrValue: ReactiveValue): string {
       break;
     }
     case 'FinishMemoize': {
-      value = `FinishMemoize decl=${printPlace(instrValue.decl)}${instrValue.pruned ? ' pruned' : ''}`;
+      value = `FinishMemoize decl=${printPlace(instrValue.decl)}`;
       break;
     }
     default: {
@@ -874,15 +863,8 @@ export function printManualMemoDependency(
   } else {
     CompilerError.invariant(val.root.value.identifier.name?.kind === 'named', {
       reason: 'DepsValidation: expected named local variable in depslist',
-      description: null,
       suggestions: null,
-      details: [
-        {
-          kind: 'error',
-          loc: val.root.value.loc,
-          message: null,
-        },
-      ],
+      loc: val.root.value.loc,
     });
     rootStr = nameOnly
       ? val.root.value.identifier.name.value
@@ -896,8 +878,7 @@ export function printType(type: Type): string {
   if (type.kind === 'Object' && type.shapeId != null) {
     return `:T${type.kind}<${type.shapeId}>`;
   } else if (type.kind === 'Function' && type.shapeId != null) {
-    const returnType = printType(type.return);
-    return `:T${type.kind}<${type.shapeId}>()${returnType !== '' ? `:  ${returnType}` : ''}`;
+    return `:T${type.kind}<${type.shapeId}>`;
   } else {
     return `:T${type.kind}`;
   }
@@ -941,110 +922,3 @@ function getFunctionName(
       return defaultValue;
   }
 }
-
-export function printAliasingEffect(effect: AliasingEffect): string {
-  switch (effect.kind) {
-    case 'Assign': {
-      return `Assign ${printPlaceForAliasEffect(effect.into)} = ${printPlaceForAliasEffect(effect.from)}`;
-    }
-    case 'Alias': {
-      return `Alias ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;
-    }
-    case 'MaybeAlias': {
-      return `MaybeAlias ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;
-    }
-    case 'Capture': {
-      return `Capture ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;
-    }
-    case 'ImmutableCapture': {
-      return `ImmutableCapture ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;
-    }
-    case 'Create': {
-      return `Create ${printPlaceForAliasEffect(effect.into)} = ${effect.value}`;
-    }
-    case 'CreateFrom': {
-      return `Create ${printPlaceForAliasEffect(effect.into)} = kindOf(${printPlaceForAliasEffect(effect.from)})`;
-    }
-    case 'CreateFunction': {
-      return `Function ${printPlaceForAliasEffect(effect.into)} = Function captures=[${effect.captures.map(printPlaceForAliasEffect).join(', ')}]`;
-    }
-    case 'Apply': {
-      const receiverCallee =
-        effect.receiver.identifier.id === effect.function.identifier.id
-          ? printPlaceForAliasEffect(effect.receiver)
-          : `${printPlaceForAliasEffect(effect.receiver)}.${printPlaceForAliasEffect(effect.function)}`;
-      const args = effect.args
-        .map(arg => {
-          if (arg.kind === 'Identifier') {
-            return printPlaceForAliasEffect(arg);
-          } else if (arg.kind === 'Hole') {
-            return ' ';
-          }
-          return `...${printPlaceForAliasEffect(arg.place)}`;
-        })
-        .join(', ');
-      let signature = '';
-      if (effect.signature != null) {
-        if (effect.signature.aliasing != null) {
-          signature = printAliasingSignature(effect.signature.aliasing);
-        } else {
-          signature = JSON.stringify(effect.signature, null, 2);
-        }
-      }
-      return `Apply ${printPlaceForAliasEffect(effect.into)} = ${receiverCallee}(${args})${signature != '' ? '\n     ' : ''}${signature}`;
-    }
-    case 'Freeze': {
-      return `Freeze ${printPlaceForAliasEffect(effect.value)} ${effect.reason}`;
-    }
-    case 'Mutate':
-    case 'MutateConditionally':
-    case 'MutateTransitive':
-    case 'MutateTransitiveConditionally': {
-      return `${effect.kind} ${printPlaceForAliasEffect(effect.value)}${effect.kind === 'Mutate' && effect.reason?.kind === 'AssignCurrentProperty' ? ' (assign `.current`)' : ''}`;
-    }
-    case 'MutateFrozen': {
-      return `MutateFrozen ${printPlaceForAliasEffect(effect.place)} reason=${JSON.stringify(effect.error.reason)}`;
-    }
-    case 'MutateGlobal': {
-      return `MutateGlobal ${printPlaceForAliasEffect(effect.place)} reason=${JSON.stringify(effect.error.reason)}`;
-    }
-    case 'Impure': {
-      return `Impure ${printPlaceForAliasEffect(effect.place)} reason=${JSON.stringify(effect.error.reason)}`;
-    }
-    case 'Render': {
-      return `Render ${printPlaceForAliasEffect(effect.place)}`;
-    }
-    default: {
-      assertExhaustive(effect, `Unexpected kind '${(effect as any).kind}'`);
-    }
-  }
-}
-
-function printPlaceForAliasEffect(place: Place): string {
-  return printIdentifier(place.identifier);
-}
-
-export function printAliasingSignature(signature: AliasingSignature): string {
-  const tokens: Array<string> = ['function '];
-  if (signature.temporaries.length !== 0) {
-    tokens.push('<');
-    tokens.push(
-      signature.temporaries.map(temp => `$${temp.identifier.id}`).join(', '),
-    );
-    tokens.push('>');
-  }
-  tokens.push('(');
-  tokens.push('this=$' + String(signature.receiver));
-  for (const param of signature.params) {
-    tokens.push(', $' + String(param));
-  }
-  if (signature.rest != null) {
-    tokens.push(`, ...$${String(signature.rest)}`);
-  }
-  tokens.push('): ');
-  tokens.push('$' + String(signature.returns) + ':');
-  for (const effect of signature.effects) {
-    tokens.push('\n  ' + printAliasingEffect(effect));
-  }
-  return tokens.join('');
-}

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

@@ -86,14 +86,7 @@ export function propagateScopeDependenciesHIR(fn: HIRFunction): void {
     const hoistables = hoistablePropertyLoads.get(scope.id);
     CompilerError.invariant(hoistables != null, {
       reason: '[PropagateScopeDependencies] Scope not found in tracked blocks',
-      description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: GeneratedSource,
-          message: null,
-        },
-      ],
+      loc: GeneratedSource,
     });
     /**
      * Step 2: Calculate hoistable dependencies.
@@ -435,14 +428,7 @@ export class DependencyCollectionContext {
     const scopedDependencies = this.#dependencies.value;
     CompilerError.invariant(scopedDependencies != null, {
       reason: '[PropagateScopeDeps]: Unexpected scope mismatch',
-      description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: scope.loc,
-          message: null,
-        },
-      ],
+      loc: scope.loc,
     });
 
     // Restore context of previous scope

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

@@ -53,14 +53,7 @@ export function pruneUnusedLabelsHIR(fn: HIRFunction): void {
       next.phis.size === 0 && fallthrough.phis.size === 0,
       {
         reason: 'Unexpected phis when merging label blocks',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: label.terminal.loc,
-            message: null,
-          },
-        ],
+        loc: label.terminal.loc,
       },
     );
 
@@ -71,14 +64,7 @@ export function pruneUnusedLabelsHIR(fn: HIRFunction): void {
         fallthrough.preds.has(nextId),
       {
         reason: 'Unexpected block predecessors when merging label blocks',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: label.terminal.loc,
-            message: null,
-          },
-        ],
+        loc: label.terminal.loc,
       },
     );
 

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

@@ -88,7 +88,6 @@ function writeNonOptionalDependency(
     },
     id: makeInstructionId(1),
     loc: loc,
-    effects: null,
   });
 
   /**
@@ -119,7 +118,6 @@ function writeNonOptionalDependency(
       },
       id: makeInstructionId(1),
       loc: loc,
-      effects: null,
     });
     curr = next;
   }
@@ -202,14 +200,8 @@ function writeOptionalDependency(
     CompilerError.invariant(firstOptional !== -1, {
       reason:
         '[ScopeDependencyUtils] Internal invariant broken: expected optional path',
+      loc: dep.identifier.loc,
       description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: dep.identifier.loc,
-          message: null,
-        },
-      ],
       suggestions: null,
     });
     if (firstOptional === dep.path.length - 1) {
@@ -245,13 +237,7 @@ function writeOptionalDependency(
     CompilerError.invariant(testIdentifier !== null, {
       reason: 'Satisfy type checker',
       description: null,
-      details: [
-        {
-          kind: 'error',
-          loc: null,
-          message: null,
-        },
-      ],
+      loc: null,
       suggestions: null,
     });
 

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

@@ -6,14 +6,9 @@
  */
 
 import {isValidIdentifier} from '@babel/types';
-import {z} from 'zod/v4';
+import {z} from 'zod';
 import {Effect, ValueKind} from '..';
-import {
-  EffectSchema,
-  ValueKindSchema,
-  ValueReason,
-  ValueReasonSchema,
-} from './HIR';
+import {EffectSchema, ValueKindSchema} from './HIR';
 
 export type ObjectPropertiesConfig = {[key: string]: TypeConfig};
 export const ObjectPropertiesSchema: z.ZodType<ObjectPropertiesConfig> = z
@@ -36,209 +31,6 @@ export const ObjectTypeSchema: z.ZodType<ObjectTypeConfig> = z.object({
   properties: ObjectPropertiesSchema.nullable(),
 });
 
-export const LifetimeIdSchema = z.string().refine(id => id.startsWith('@'), {
-  message: "Placeholder names must start with '@'",
-});
-
-export type FreezeEffectConfig = {
-  kind: 'Freeze';
-  value: string;
-  reason: ValueReason;
-};
-
-export const FreezeEffectSchema: z.ZodType<FreezeEffectConfig> = z.object({
-  kind: z.literal('Freeze'),
-  value: LifetimeIdSchema,
-  reason: ValueReasonSchema,
-});
-
-export type MutateEffectConfig = {
-  kind: 'Mutate';
-  value: string;
-};
-
-export const MutateEffectSchema: z.ZodType<MutateEffectConfig> = z.object({
-  kind: z.literal('Mutate'),
-  value: LifetimeIdSchema,
-});
-
-export type MutateTransitiveConditionallyConfig = {
-  kind: 'MutateTransitiveConditionally';
-  value: string;
-};
-
-export const MutateTransitiveConditionallySchema: z.ZodType<MutateTransitiveConditionallyConfig> =
-  z.object({
-    kind: z.literal('MutateTransitiveConditionally'),
-    value: LifetimeIdSchema,
-  });
-
-export type CreateEffectConfig = {
-  kind: 'Create';
-  into: string;
-  value: ValueKind;
-  reason: ValueReason;
-};
-
-export const CreateEffectSchema: z.ZodType<CreateEffectConfig> = z.object({
-  kind: z.literal('Create'),
-  into: LifetimeIdSchema,
-  value: ValueKindSchema,
-  reason: ValueReasonSchema,
-});
-
-export type AssignEffectConfig = {
-  kind: 'Assign';
-  from: string;
-  into: string;
-};
-
-export const AssignEffectSchema: z.ZodType<AssignEffectConfig> = z.object({
-  kind: z.literal('Assign'),
-  from: LifetimeIdSchema,
-  into: LifetimeIdSchema,
-});
-
-export type AliasEffectConfig = {
-  kind: 'Alias';
-  from: string;
-  into: string;
-};
-
-export const AliasEffectSchema: z.ZodType<AliasEffectConfig> = z.object({
-  kind: z.literal('Alias'),
-  from: LifetimeIdSchema,
-  into: LifetimeIdSchema,
-});
-
-export type ImmutableCaptureEffectConfig = {
-  kind: 'ImmutableCapture';
-  from: string;
-  into: string;
-};
-
-export const ImmutableCaptureEffectSchema: z.ZodType<ImmutableCaptureEffectConfig> =
-  z.object({
-    kind: z.literal('ImmutableCapture'),
-    from: LifetimeIdSchema,
-    into: LifetimeIdSchema,
-  });
-
-export type CaptureEffectConfig = {
-  kind: 'Capture';
-  from: string;
-  into: string;
-};
-
-export const CaptureEffectSchema: z.ZodType<CaptureEffectConfig> = z.object({
-  kind: z.literal('Capture'),
-  from: LifetimeIdSchema,
-  into: LifetimeIdSchema,
-});
-
-export type CreateFromEffectConfig = {
-  kind: 'CreateFrom';
-  from: string;
-  into: string;
-};
-
-export const CreateFromEffectSchema: z.ZodType<CreateFromEffectConfig> =
-  z.object({
-    kind: z.literal('CreateFrom'),
-    from: LifetimeIdSchema,
-    into: LifetimeIdSchema,
-  });
-
-export type ApplyArgConfig =
-  | string
-  | {kind: 'Spread'; place: string}
-  | {kind: 'Hole'};
-
-export const ApplyArgSchema: z.ZodType<ApplyArgConfig> = z.union([
-  LifetimeIdSchema,
-  z.object({
-    kind: z.literal('Spread'),
-    place: LifetimeIdSchema,
-  }),
-  z.object({
-    kind: z.literal('Hole'),
-  }),
-]);
-
-export type ApplyEffectConfig = {
-  kind: 'Apply';
-  receiver: string;
-  function: string;
-  mutatesFunction: boolean;
-  args: Array<ApplyArgConfig>;
-  into: string;
-};
-
-export const ApplyEffectSchema: z.ZodType<ApplyEffectConfig> = z.object({
-  kind: z.literal('Apply'),
-  receiver: LifetimeIdSchema,
-  function: LifetimeIdSchema,
-  mutatesFunction: z.boolean(),
-  args: z.array(ApplyArgSchema),
-  into: LifetimeIdSchema,
-});
-
-export type ImpureEffectConfig = {
-  kind: 'Impure';
-  place: string;
-};
-
-export const ImpureEffectSchema: z.ZodType<ImpureEffectConfig> = z.object({
-  kind: z.literal('Impure'),
-  place: LifetimeIdSchema,
-});
-
-export type AliasingEffectConfig =
-  | FreezeEffectConfig
-  | CreateEffectConfig
-  | CreateFromEffectConfig
-  | AssignEffectConfig
-  | AliasEffectConfig
-  | CaptureEffectConfig
-  | ImmutableCaptureEffectConfig
-  | ImpureEffectConfig
-  | MutateEffectConfig
-  | MutateTransitiveConditionallyConfig
-  | ApplyEffectConfig;
-
-export const AliasingEffectSchema: z.ZodType<AliasingEffectConfig> = z.union([
-  FreezeEffectSchema,
-  CreateEffectSchema,
-  CreateFromEffectSchema,
-  AssignEffectSchema,
-  AliasEffectSchema,
-  CaptureEffectSchema,
-  ImmutableCaptureEffectSchema,
-  ImpureEffectSchema,
-  MutateEffectSchema,
-  MutateTransitiveConditionallySchema,
-  ApplyEffectSchema,
-]);
-
-export type AliasingSignatureConfig = {
-  receiver: string;
-  params: Array<string>;
-  rest: string | null;
-  returns: string;
-  effects: Array<AliasingEffectConfig>;
-  temporaries: Array<string>;
-};
-
-export const AliasingSignatureSchema: z.ZodType<AliasingSignatureConfig> =
-  z.object({
-    receiver: LifetimeIdSchema,
-    params: z.array(LifetimeIdSchema),
-    rest: LifetimeIdSchema.nullable(),
-    returns: LifetimeIdSchema,
-    effects: z.array(AliasingEffectSchema),
-    temporaries: z.array(LifetimeIdSchema),
-  });
-
 export type FunctionTypeConfig = {
   kind: 'function';
   positionalParams: Array<Effect>;
@@ -250,8 +42,6 @@ export type FunctionTypeConfig = {
   mutableOnlyIfOperandsAreMutable?: boolean | null | undefined;
   impure?: boolean | null | undefined;
   canonicalName?: string | null | undefined;
-  aliasing?: AliasingSignatureConfig | null | undefined;
-  knownIncompatible?: string | null | undefined;
 };
 export const FunctionTypeSchema: z.ZodType<FunctionTypeConfig> = z.object({
   kind: z.literal('function'),
@@ -264,8 +54,6 @@ export const FunctionTypeSchema: z.ZodType<FunctionTypeConfig> = z.object({
   mutableOnlyIfOperandsAreMutable: z.boolean().nullable().optional(),
   impure: z.boolean().nullable().optional(),
   canonicalName: z.string().nullable().optional(),
-  aliasing: AliasingSignatureSchema.nullable().optional(),
-  knownIncompatible: z.string().nullable().optional(),
 });
 
 export type HookTypeConfig = {
@@ -275,8 +63,6 @@ export type HookTypeConfig = {
   returnType: TypeConfig;
   returnValueKind?: ValueKind | null | undefined;
   noAlias?: boolean | null | undefined;
-  aliasing?: AliasingSignatureConfig | null | undefined;
-  knownIncompatible?: string | null | undefined;
 };
 export const HookTypeSchema: z.ZodType<HookTypeConfig> = z.object({
   kind: z.literal('hook'),
@@ -285,8 +71,6 @@ export const HookTypeSchema: z.ZodType<HookTypeConfig> = z.object({
   returnType: z.lazy(() => TypeSchema),
   returnValueKind: ValueKindSchema.nullable().optional(),
   noAlias: z.boolean().nullable().optional(),
-  aliasing: AliasingSignatureSchema.nullable().optional(),
-  knownIncompatible: z.string().nullable().optional(),
 });
 
 export type BuiltInTypeConfig =

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

@@ -87,13 +87,7 @@ export function makeTypeId(id: number): TypeId {
   CompilerError.invariant(id >= 0 && Number.isInteger(id), {
     reason: 'Expected instruction id to be a non-negative integer',
     description: null,
-    details: [
-      {
-        kind: 'error',
-        loc: null,
-        message: null,
-      },
-    ],
+    loc: null,
     suggestions: null,
   });
   return id as TypeId;

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

@@ -345,51 +345,6 @@ export function* eachPatternOperand(pattern: Pattern): Iterable<Place> {
   }
 }
 
-export function* eachPatternItem(
-  pattern: Pattern,
-): Iterable<Place | SpreadPattern> {
-  switch (pattern.kind) {
-    case 'ArrayPattern': {
-      for (const item of pattern.items) {
-        if (item.kind === 'Identifier') {
-          yield item;
-        } else if (item.kind === 'Spread') {
-          yield item;
-        } else if (item.kind === 'Hole') {
-          continue;
-        } else {
-          assertExhaustive(
-            item,
-            `Unexpected item kind \`${(item as any).kind}\``,
-          );
-        }
-      }
-      break;
-    }
-    case 'ObjectPattern': {
-      for (const property of pattern.properties) {
-        if (property.kind === 'ObjectProperty') {
-          yield property.place;
-        } else if (property.kind === 'Spread') {
-          yield property;
-        } else {
-          assertExhaustive(
-            property,
-            `Unexpected item kind \`${(property as any).kind}\``,
-          );
-        }
-      }
-      break;
-    }
-    default: {
-      assertExhaustive(
-        pattern,
-        `Unexpected pattern kind \`${(pattern as any).kind}\``,
-      );
-    }
-  }
-}
-
 export function mapInstructionLValues(
   instr: Instruction,
   fn: (place: Place) => Place,
@@ -777,11 +732,9 @@ export function mapTerminalSuccessors(
     case 'return': {
       return {
         kind: 'return',
-        returnVariant: terminal.returnVariant,
         loc: terminal.loc,
         value: terminal.value,
         id: makeInstructionId(0),
-        effects: terminal.effects,
       };
     }
     case 'throw': {
@@ -889,7 +842,6 @@ export function mapTerminalSuccessors(
         handler,
         id: makeInstructionId(0),
         loc: terminal.loc,
-        effects: terminal.effects,
       };
     }
     case 'try': {
@@ -1233,14 +1185,7 @@ export class ScopeBlockTraversal {
       CompilerError.invariant(blockInfo.scope.id === top, {
         reason:
           'Expected traversed block fallthrough to match top-most active scope',
-        description: null,
-        details: [
-          {
-            kind: 'error',
-            loc: block.instructions[0]?.loc ?? block.terminal.id,
-            message: null,
-          },
-        ],
+        loc: block.instructions[0]?.loc ?? block.terminal.id,
       });
       this.#activeScopes.pop();
     }
@@ -1254,14 +1199,7 @@ export class ScopeBlockTraversal {
           !this.blockInfos.has(block.terminal.fallthrough),
         {
           reason: 'Expected unique scope blocks and fallthroughs',
-          description: null,
-          details: [
-            {
-              kind: 'error',
-              loc: block.terminal.loc,
-              message: null,
-            },
-          ],
+          loc: block.terminal.loc,
         },
       );
       this.blockInfos.set(block.terminal.block, {

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

@@ -1,264 +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 {CompilerDiagnostic} from '../CompilerError';
-import {
-  FunctionExpression,
-  GeneratedSource,
-  Hole,
-  IdentifierId,
-  ObjectMethod,
-  Place,
-  SourceLocation,
-  SpreadPattern,
-  ValueKind,
-  ValueReason,
-} from '../HIR';
-import {FunctionSignature} from '../HIR/ObjectShape';
-import {printSourceLocation} from '../HIR/PrintHIR';
-
-/**
- * `AliasingEffect` describes a set of "effects" that an instruction/terminal has on one or
- * more values in a program. These effects include mutation of values, freezing values,
- * tracking data flow between values, and other specialized cases.
- */
-export type AliasingEffect =
-  /**
-   * Marks the given value and its direct aliases as frozen.
-   *
-   * Captured values are *not* considered frozen, because we cannot be sure that a previously
-   * captured value will still be captured at the point of the freeze.
-   *
-   * For example:
-   * const x = {};
-   * const y = [x];
-   * y.pop(); // y dosn't contain x anymore!
-   * freeze(y);
-   * mutate(x); // safe to mutate!
-   *
-   * The exception to this is FunctionExpressions - since it is impossible to change which
-   * value a function closes over[1] we can transitively freeze functions and their captures.
-   *
-   * [1] Except for `let` values that are reassigned and closed over by a function, but we
-   * handle this explicitly with StoreContext/LoadContext.
-   */
-  | {kind: 'Freeze'; value: Place; reason: ValueReason}
-  /**
-   * Mutate the value and any direct aliases (not captures). Errors if the value is not mutable.
-   */
-  | {kind: 'Mutate'; value: Place; reason?: MutationReason | null}
-  /**
-   * Mutate the value and any direct aliases (not captures), but only if the value is known mutable.
-   * This should be rare.
-   *
-   * TODO: this is only used for IteratorNext, but even then MutateTransitiveConditionally is more
-   * correct for iterators of unknown types.
-   */
-  | {kind: 'MutateConditionally'; value: Place}
-  /**
-   * Mutate the value, any direct aliases, and any transitive captures. Errors if the value is not mutable.
-   */
-  | {kind: 'MutateTransitive'; value: Place}
-  /**
-   * Mutates any of the value, its direct aliases, and its transitive captures that are mutable.
-   */
-  | {kind: 'MutateTransitiveConditionally'; value: Place}
-  /**
-   * Records information flow from `from` to `into` in cases where local mutation of the destination
-   * will *not* mutate the source:
-   *
-   * - Capture a -> b and Mutate(b) X=> (does not imply) Mutate(a)
-   * - Capture a -> b and MutateTransitive(b) => (does imply) Mutate(a)
-   *
-   * Example: `array.push(item)`. Information from item is captured into array, but there is not a
-   * direct aliasing, and local mutations of array will not modify item.
-   */
-  | {kind: 'Capture'; from: Place; into: Place}
-  /**
-   * Records information flow from `from` to `into` in cases where local mutation of the destination
-   * *will* mutate the source:
-   *
-   * - Alias a -> b and Mutate(b) => (does imply) Mutate(a)
-   * - Alias a -> b and MutateTransitive(b) => (does imply) Mutate(a)
-   *
-   * Example: `c = identity(a)`. We don't know what `identity()` returns so we can't use Assign.
-   * But we have to assume that it _could_ be returning its input, such that a local mutation of
-   * c could be mutating a.
-   */
-  | {kind: 'Alias'; from: Place; into: Place}
-
-  /**
-   * Indicates the potential for information flow from `from` to `into`. This is used for a specific
-   * case: functions with unknown signatures. If the compiler sees a call such as `foo(x)`, it has to
-   * consider several possibilities (which may depend on the arguments):
-   * - foo(x) returns a new mutable value that does not capture any information from x.
-   * - foo(x) returns a new mutable value that *does* capture information from x.
-   * - foo(x) returns x itself, ie foo is the identity function
-   *
-   * The same is true of functions that take multiple arguments: `cond(a, b, c)` could conditionally
-   * return b or c depending on the value of a.
-   *
-   * To represent this case, MaybeAlias represents the fact that an aliasing relationship could exist.
-   * Any mutations that flow through this relationship automatically become conditional.
-   */
-  | {kind: 'MaybeAlias'; from: Place; into: Place}
-
-  /**
-   * Records direct assignment: `into = from`.
-   */
-  | {kind: 'Assign'; from: Place; into: Place}
-  /**
-   * Creates a value of the given type at the given place
-   */
-  | {kind: 'Create'; into: Place; value: ValueKind; reason: ValueReason}
-  /**
-   * Creates a new value with the same kind as the starting value.
-   */
-  | {kind: 'CreateFrom'; from: Place; into: Place}
-  /**
-   * Immutable data flow, used for escape analysis. Does not influence mutable range analysis:
-   */
-  | {kind: 'ImmutableCapture'; from: Place; into: Place}
-  /**
-   * Calls the function at the given place with the given arguments either captured or aliased,
-   * and captures/aliases the result into the given place.
-   */
-  | {
-      kind: 'Apply';
-      receiver: Place;
-      function: Place;
-      mutatesFunction: boolean;
-      args: Array<Place | SpreadPattern | Hole>;
-      into: Place;
-      signature: FunctionSignature | null;
-      loc: SourceLocation;
-    }
-  /**
-   * Constructs a function value with the given captures. The mutability of the function
-   * will be determined by the mutability of the capture values when evaluated.
-   */
-  | {
-      kind: 'CreateFunction';
-      captures: Array<Place>;
-      function: FunctionExpression | ObjectMethod;
-      into: Place;
-    }
-  /**
-   * Mutation of a value known to be immutable
-   */
-  | {kind: 'MutateFrozen'; place: Place; error: CompilerDiagnostic}
-  /**
-   * Mutation of a global
-   */
-  | {
-      kind: 'MutateGlobal';
-      place: Place;
-      error: CompilerDiagnostic;
-    }
-  /**
-   * Indicates a side-effect that is not safe during render
-   */
-  | {kind: 'Impure'; place: Place; error: CompilerDiagnostic}
-  /**
-   * Indicates that a given place is accessed during render. Used to distingush
-   * hook arguments that are known to be called immediately vs those used for
-   * event handlers/effects, and for JSX values known to be called during render
-   * (tags, children) vs those that may be events/effect (other props).
-   */
-  | {
-      kind: 'Render';
-      place: Place;
-    };
-
-export type MutationReason = {kind: 'AssignCurrentProperty'};
-
-export function hashEffect(effect: AliasingEffect): string {
-  switch (effect.kind) {
-    case 'Apply': {
-      return [
-        effect.kind,
-        effect.receiver.identifier.id,
-        effect.function.identifier.id,
-        effect.mutatesFunction,
-        effect.args
-          .map(a => {
-            if (a.kind === 'Hole') {
-              return '';
-            } else if (a.kind === 'Identifier') {
-              return a.identifier.id;
-            } else {
-              return `...${a.place.identifier.id}`;
-            }
-          })
-          .join(','),
-        effect.into.identifier.id,
-      ].join(':');
-    }
-    case 'CreateFrom':
-    case 'ImmutableCapture':
-    case 'Assign':
-    case 'Alias':
-    case 'Capture':
-    case 'MaybeAlias': {
-      return [
-        effect.kind,
-        effect.from.identifier.id,
-        effect.into.identifier.id,
-      ].join(':');
-    }
-    case 'Create': {
-      return [
-        effect.kind,
-        effect.into.identifier.id,
-        effect.value,
-        effect.reason,
-      ].join(':');
-    }
-    case 'Freeze': {
-      return [effect.kind, effect.value.identifier.id, effect.reason].join(':');
-    }
-    case 'Impure':
-    case 'Render': {
-      return [effect.kind, effect.place.identifier.id].join(':');
-    }
-    case 'MutateFrozen':
-    case 'MutateGlobal': {
-      return [
-        effect.kind,
-        effect.place.identifier.id,
-        effect.error.severity,
-        effect.error.reason,
-        effect.error.description,
-        printSourceLocation(effect.error.primaryLocation() ?? GeneratedSource),
-      ].join(':');
-    }
-    case 'Mutate':
-    case 'MutateConditionally':
-    case 'MutateTransitive':
-    case 'MutateTransitiveConditionally': {
-      return [effect.kind, effect.value.identifier.id].join(':');
-    }
-    case 'CreateFunction': {
-      return [
-        effect.kind,
-        effect.into.identifier.id,
-        // return places are a unique way to identify functions themselves
-        effect.function.loweredFunc.func.returns.identifier.id,
-        effect.captures.map(p => p.identifier.id).join(','),
-      ].join(':');
-    }
-  }
-}
-
-export type AliasingSignature = {
-  receiver: IdentifierId;
-  params: Array<IdentifierId>;
-  rest: IdentifierId | null;
-  returns: IdentifierId;
-  effects: Array<AliasingEffect>;
-  temporaries: Array<Place>;
-};

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

@@ -6,13 +6,19 @@
  */
 
 import {CompilerError} from '../CompilerError';
-import {Effect, HIRFunction, IdentifierId, makeInstructionId} from '../HIR';
+import {
+  Effect,
+  HIRFunction,
+  Identifier,
+  LoweredFunction,
+  isRefOrRefValue,
+  makeInstructionId,
+} from '../HIR';
 import {deadCodeElimination} from '../Optimization';
 import {inferReactiveScopeVariables} from '../ReactiveScopes';
 import {rewriteInstructionKindsBasedOnReassignment} from '../SSA';
-import {assertExhaustive} from '../Utils/utils';
-import {inferMutationAliasingEffects} from './InferMutationAliasingEffects';
-import {inferMutationAliasingRanges} from './InferMutationAliasingRanges';
+import {inferMutableRanges} from './InferMutableRanges';
+import inferReferenceEffects from './InferReferenceEffects';
 
 export default function analyseFunctions(func: HIRFunction): void {
   for (const [_, block] of func.body.blocks) {
@@ -20,22 +26,15 @@ export default function analyseFunctions(func: HIRFunction): void {
       switch (instr.value.kind) {
         case 'ObjectMethod':
         case 'FunctionExpression': {
-          lowerWithMutationAliasing(instr.value.loweredFunc.func);
+          lower(instr.value.loweredFunc.func);
+          infer(instr.value.loweredFunc);
 
           /**
            * Reset mutable range for outer inferReferenceEffects
            */
           for (const operand of instr.value.loweredFunc.func.context) {
-            /**
-             * NOTE: inferReactiveScopeVariables makes identifiers in the scope
-             * point to the *same* mutableRange instance. Resetting start/end
-             * here is insufficient, because a later mutation of the range
-             * for any one identifier could affect the range for other identifiers.
-             */
-            operand.identifier.mutableRange = {
-              start: makeInstructionId(0),
-              end: makeInstructionId(0),
-            };
+            operand.identifier.mutableRange.start = makeInstructionId(0);
+            operand.identifier.mutableRange.end = makeInstructionId(0);
             operand.identifier.scope = null;
           }
           break;
@@ -45,90 +44,57 @@ export default function analyseFunctions(func: HIRFunction): void {
   }
 }
 
-function lowerWithMutationAliasing(fn: HIRFunction): void {
-  /**
-   * Phase 1: similar to lower(), but using the new mutation/aliasing inference
-   */
-  analyseFunctions(fn);
-  inferMutationAliasingEffects(fn, {isFunctionExpression: true});
-  deadCodeElimination(fn);
-  const functionEffects = inferMutationAliasingRanges(fn, {
-    isFunctionExpression: true,
-  }).unwrap();
-  rewriteInstructionKindsBasedOnReassignment(fn);
-  inferReactiveScopeVariables(fn);
-  fn.aliasingEffects = functionEffects;
+function lower(func: HIRFunction): void {
+  analyseFunctions(func);
+  inferReferenceEffects(func, {isFunctionExpression: true});
+  deadCodeElimination(func);
+  inferMutableRanges(func);
+  rewriteInstructionKindsBasedOnReassignment(func);
+  inferReactiveScopeVariables(func);
+  func.env.logger?.debugLogIRs?.({
+    kind: 'hir',
+    name: 'AnalyseFunction (inner)',
+    value: func,
+  });
+}
 
-  /**
-   * Phase 2: populate the Effect of each context variable to use in inferring
-   * the outer function. For example, InferMutationAliasingEffects uses context variable
-   * effects to decide if the function may be mutable or not.
-   */
-  const capturedOrMutated = new Set<IdentifierId>();
-  for (const effect of functionEffects) {
-    switch (effect.kind) {
-      case 'Assign':
-      case 'Alias':
-      case 'Capture':
-      case 'CreateFrom':
-      case 'MaybeAlias': {
-        capturedOrMutated.add(effect.from.identifier.id);
-        break;
-      }
-      case 'Apply': {
-        CompilerError.invariant(false, {
-          reason: `[AnalyzeFunctions] Expected Apply effects to be replaced with more precise effects`,
-          description: null,
-          details: [
-            {
-              kind: 'error',
-              loc: effect.function.loc,
-              message: null,
-            },
-          ],
-        });
-      }
-      case 'Mutate':
-      case 'MutateConditionally':
-      case 'MutateTransitive':
-      case 'MutateTransitiveConditionally': {
-        capturedOrMutated.add(effect.value.identifier.id);
-        break;
-      }
-      case 'Impure':
-      case 'Render':
-      case 'MutateFrozen':
-      case 'MutateGlobal':
-      case 'CreateFunction':
-      case 'Create':
-      case 'Freeze':
-      case 'ImmutableCapture': {
-        // no-op
-        break;
-      }
-      default: {
-        assertExhaustive(
-          effect,
-          `Unexpected effect kind ${(effect as any).kind}`,
-        );
-      }
-    }
-  }
-
-  for (const operand of fn.context) {
-    if (
-      capturedOrMutated.has(operand.identifier.id) ||
-      operand.effect === Effect.Capture
-    ) {
+function infer(loweredFunc: LoweredFunction): void {
+  for (const operand of loweredFunc.func.context) {
+    const identifier = operand.identifier;
+    CompilerError.invariant(operand.effect === Effect.Unknown, {
+      reason:
+        '[AnalyseFunctions] Expected Function context effects to not have been set',
+      loc: operand.loc,
+    });
+    if (isRefOrRefValue(identifier)) {
+      /*
+       * TODO: this is a hack to ensure we treat functions which reference refs
+       * as having a capture and therefore being considered mutable. this ensures
+       * the function gets a mutable range which accounts for anywhere that it
+       * could be called, and allows us to help ensure it isn't called during
+       * render
+       */
+      operand.effect = Effect.Capture;
+    } else if (isMutatedOrReassigned(identifier)) {
+      /**
+       * Reflects direct reassignments, PropertyStores, and ConditionallyMutate
+       * (directly or through maybe-aliases)
+       */
       operand.effect = Effect.Capture;
     } else {
       operand.effect = Effect.Read;
     }
   }
-
-  fn.env.logger?.debugLogIRs?.({
-    kind: 'hir',
-    name: 'AnalyseFunction (inner)',
-    value: fn,
-  });
+}
+
+function isMutatedOrReassigned(id: Identifier): boolean {
+  /*
+   * This check checks for mutation and reassingnment, so the usual check for
+   * mutation (ie, `mutableRange.end - mutableRange.start > 1`) isn't quite
+   * enough.
+   *
+   * We need to track re-assignments in context refs as we need to reflect the
+   * re-assignment back to the captured refs.
+   */
+  return id.mutableRange.end > id.mutableRange.start;
 }

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

@@ -5,8 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {CompilerDiagnostic, CompilerError, SourceLocation} from '..';
-import {ErrorCategory} from '../CompilerError';
+import {CompilerError, SourceLocation} from '..';
 import {
   CallExpression,
   Effect,
@@ -31,7 +30,6 @@ import {
   makeInstructionId,
 } from '../HIR';
 import {createTemporaryPlace, markInstructionIds} from '../HIR/HIRBuilder';
-import {Result} from '../Utils/Result';
 
 type ManualMemoCallee = {
   kind: 'useMemo' | 'useCallback';
@@ -199,7 +197,6 @@ function makeManualMemoizationMarkers(
         deps: depsList,
         loc: fnExpr.loc,
       },
-      effects: null,
       loc: fnExpr.loc,
     },
     {
@@ -211,7 +208,6 @@ function makeManualMemoizationMarkers(
         decl: {...memoDecl},
         loc: fnExpr.loc,
       },
-      effects: null,
       loc: fnExpr.loc,
     },
   ];
@@ -285,43 +281,26 @@ function extractManualMemoizationArgs(
   instr: TInstruction<CallExpression> | TInstruction<MethodCall>,
   kind: 'useCallback' | 'useMemo',
   sidemap: IdentifierSidemap,
-  errors: CompilerError,
 ): {
-  fnPlace: Place | null;
+  fnPlace: Place;
   depsList: Array<ManualMemoDependency> | null;
 } {
   const [fnPlace, depsListPlace] = instr.value.args as Array<
     Place | SpreadPattern | undefined
   >;
   if (fnPlace == null) {
-    errors.pushDiagnostic(
-      CompilerDiagnostic.create({
-        category: ErrorCategory.UseMemo,
-        reason: `Expected a callback function to be passed to ${kind}`,
-        description: `Expected a callback function to be passed to ${kind}`,
-        suggestions: null,
-      }).withDetails({
-        kind: 'error',
-        loc: instr.value.loc,
-        message: `Expected a callback function to be passed to ${kind}`,
-      }),
-    );
-    return {fnPlace: null, depsList: null};
+    CompilerError.throwInvalidReact({
+      reason: `Expected a callback function to be passed to ${kind}`,
+      loc: instr.value.loc,
+      suggestions: null,
+    });
   }
   if (fnPlace.kind === 'Spread' || depsListPlace?.kind === 'Spread') {
-    errors.pushDiagnostic(
-      CompilerDiagnostic.create({
-        category: ErrorCategory.UseMemo,
-        reason: `Unexpected spread argument to ${kind}`,
-        description: `Unexpected spread argument to ${kind}`,
-        suggestions: null,
-      }).withDetails({
-        kind: 'error',
-        loc: instr.value.loc,
-        message: `Unexpected spread argument to ${kind}`,
-      }),
-    );
-    return {fnPlace: null, depsList: null};
+    CompilerError.throwInvalidReact({
+      reason: `Unexpected spread argument to ${kind}`,
+      loc: instr.value.loc,
+      suggestions: null,
+    });
   }
   let depsList: Array<ManualMemoDependency> | null = null;
   if (depsListPlace != null) {
@@ -329,40 +308,23 @@ function extractManualMemoizationArgs(
       depsListPlace.identifier.id,
     );
     if (maybeDepsList == null) {
-      errors.pushDiagnostic(
-        CompilerDiagnostic.create({
-          category: ErrorCategory.UseMemo,
-          reason: `Expected the dependency list for ${kind} to be an array literal`,
-          description: `Expected the dependency list for ${kind} to be an array literal`,
-          suggestions: null,
-        }).withDetails({
-          kind: 'error',
-          loc: depsListPlace.loc,
-          message: `Expected the dependency list for ${kind} to be an array literal`,
-        }),
-      );
-      return {fnPlace, depsList: null};
+      CompilerError.throwInvalidReact({
+        reason: `Expected the dependency list for ${kind} to be an array literal`,
+        suggestions: null,
+        loc: depsListPlace.loc,
+      });
     }
-    depsList = [];
-    for (const dep of maybeDepsList) {
+    depsList = maybeDepsList.map(dep => {
       const maybeDep = sidemap.maybeDeps.get(dep.identifier.id);
       if (maybeDep == null) {
-        errors.pushDiagnostic(
-          CompilerDiagnostic.create({
-            category: ErrorCategory.UseMemo,
-            reason: `Expected the dependency list to be an array of simple expressions (e.g. \`x\`, \`x.y.z\`, \`x?.y?.z\`)`,
-            description: `Expected the dependency list to be an array of simple expressions (e.g. \`x\`, \`x.y.z\`, \`x?.y?.z\`)`,
-            suggestions: null,
-          }).withDetails({
-            kind: 'error',
-            loc: dep.loc,
-            message: `Expected the dependency list to be an array of simple expressions (e.g. \`x\`, \`x.y.z\`, \`x?.y?.z\`)`,
-          }),
-        );
-      } else {
-        depsList.push(maybeDep);
+        CompilerError.throwInvalidReact({
+          reason: `Expected the dependency list to be an array of simple expressions (e.g. \`x\`, \`x.y.z\`, \`x?.y?.z\`)`,
+          suggestions: null,
+          loc: dep.loc,
+        });
       }
-    }
+      return maybeDep;
+    });
   }
   return {
     fnPlace,
@@ -377,14 +339,8 @@ function extractManualMemoizationArgs(
  * rely on type inference to find useMemo/useCallback invocations, and instead does basic tracking
  * of globals and property loads to find both direct calls as well as usage via the React namespace,
  * eg `React.useMemo()`.
- *
- * This pass also validates that useMemo callbacks return a value (not void), ensuring that useMemo
- * is only used for memoizing values and not for running arbitrary side effects.
  */
-export function dropManualMemoization(
-  func: HIRFunction,
-): Result<void, CompilerError> {
-  const errors = new CompilerError();
+export function dropManualMemoization(func: HIRFunction): void {
   const isValidationEnabled =
     func.env.config.validatePreserveExistingMemoizationGuarantees ||
     func.env.config.validateNoSetStateInRender ||
@@ -431,13 +387,7 @@ export function dropManualMemoization(
             instr as TInstruction<CallExpression> | TInstruction<MethodCall>,
             manualMemo.kind,
             sidemap,
-            errors,
           );
-
-          if (fnPlace == null) {
-            continue;
-          }
-
           instr.value = getManualMemoizationReplacement(
             fnPlace,
             instr.value.loc,
@@ -458,19 +408,11 @@ export function dropManualMemoization(
              * is rare and likely sketchy.
              */
             if (!sidemap.functions.has(fnPlace.identifier.id)) {
-              errors.pushDiagnostic(
-                CompilerDiagnostic.create({
-                  category: ErrorCategory.UseMemo,
-                  reason: `Expected the first argument to be an inline function expression`,
-                  description: `Expected the first argument to be an inline function expression`,
-                  suggestions: [],
-                }).withDetails({
-                  kind: 'error',
-                  loc: fnPlace.loc,
-                  message: `Expected the first argument to be an inline function expression`,
-                }),
-              );
-              continue;
+              CompilerError.throwInvalidReact({
+                reason: `Expected the first argument to be an inline function expression`,
+                suggestions: [],
+                loc: fnPlace.loc,
+              });
             }
             const memoDecl: Place =
               manualMemo.kind === 'useMemo'
@@ -542,8 +484,6 @@ export function dropManualMemoization(
       markInstructionIds(func.body);
     }
   }
-
-  return errors.asResult();
 }
 
 function findOptionalPlaces(fn: HIRFunction): Set<IdentifierId> {
@@ -579,14 +519,7 @@ function findOptionalPlaces(fn: HIRFunction): Set<IdentifierId> {
           default: {
             CompilerError.invariant(false, {
               reason: `Unexpected terminal in optional`,
-              description: null,
-              details: [
-                {
-                  kind: 'error',
-                  loc: terminal.loc,
-                  message: `Unexpected ${terminal.kind} in optional`,
-                },
-              ],
+              loc: terminal.loc,
             });
           }
         }

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

@@ -0,0 +1,134 @@
+/**
+ * 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 {
+  Effect,
+  HIRFunction,
+  Identifier,
+  isMutableEffect,
+  isRefOrRefLikeMutableType,
+  makeInstructionId,
+} from '../HIR/HIR';
+import {eachInstructionValueOperand} from '../HIR/visitors';
+import {isMutable} from '../ReactiveScopes/InferReactiveScopeVariables';
+import DisjointSet from '../Utils/DisjointSet';
+
+/**
+ * If a function captures a mutable value but never gets called, we don't infer a
+ * mutable range for that function. This means that we also don't alias the function
+ * with its mutable captures.
+ *
+ * This case is tricky, because we don't generally know for sure what is a mutation
+ * and what may just be a normal function call. For example:
+ *
+ * ```
+ * hook useFoo() {
+ *   const x = makeObject();
+ *   return () => {
+ *     return readObject(x); // could be a mutation!
+ *   }
+ * }
+ * ```
+ *
+ * If we pessimistically assume that all such cases are mutations, we'd have to group
+ * lots of memo scopes together unnecessarily. However, if there is definitely a mutation:
+ *
+ * ```
+ * hook useFoo(createEntryForKey) {
+ *   const cache = new WeakMap();
+ *   return (key) => {
+ *     let entry = cache.get(key);
+ *     if (entry == null) {
+ *       entry = createEntryForKey(key);
+ *       cache.set(key, entry); // known mutation!
+ *     }
+ *     return entry;
+ *   }
+ * }
+ * ```
+ *
+ * Then we have to ensure that the function and its mutable captures alias together and
+ * end up in the same scope. However, aliasing together isn't enough if the function
+ * and operands all have empty mutable ranges (end = start + 1).
+ *
+ * This pass finds function expressions and object methods that have an empty mutable range
+ * and known-mutable operands which also don't have a mutable range, and ensures that the
+ * function and those operands are aliased together *and* that their ranges are updated to
+ * end after the function expression. This is sufficient to ensure that a reactive scope is
+ * created for the alias set.
+ */
+export function inferAliasForUncalledFunctions(
+  fn: HIRFunction,
+  aliases: DisjointSet<Identifier>,
+): void {
+  for (const block of fn.body.blocks.values()) {
+    instrs: for (const instr of block.instructions) {
+      const {lvalue, value} = instr;
+      if (
+        value.kind !== 'ObjectMethod' &&
+        value.kind !== 'FunctionExpression'
+      ) {
+        continue;
+      }
+      /*
+       * If the function is known to be mutated, we will have
+       * already aliased any mutable operands with it
+       */
+      const range = lvalue.identifier.mutableRange;
+      if (range.end > range.start + 1) {
+        continue;
+      }
+      /*
+       * If the function already has operands with an active mutable range,
+       * then we don't need to do anything — the function will have already
+       * been visited and included in some mutable alias set. This case can
+       * also occur due to visiting the same function in an earlier iteration
+       * of the outer fixpoint loop.
+       */
+      for (const operand of eachInstructionValueOperand(value)) {
+        if (isMutable(instr, operand)) {
+          continue instrs;
+        }
+      }
+      const operands: Set<Identifier> = new Set();
+      for (const effect of value.loweredFunc.func.effects ?? []) {
+        if (effect.kind !== 'ContextMutation') {
+          continue;
+        }
+        /*
+         * We're looking for known-mutations only, so we look at the effects
+         * rather than function context
+         */
+        if (effect.effect === Effect.Store || effect.effect === Effect.Mutate) {
+          for (const operand of effect.places) {
+            /*
+             * It's possible that function effect analysis thinks there was a context mutation,
+             * but then InferReferenceEffects figures out some operands are globals and therefore
+             * creates a non-mutable effect for those operands.
+             * We should change InferReferenceEffects to swap the ContextMutation for a global
+             * mutation in that case, but for now we just filter them out here
+             */
+            if (
+              isMutableEffect(operand.effect, operand.loc) &&
+              !isRefOrRefLikeMutableType(operand.identifier.type)
+            ) {
+              operands.add(operand.identifier);
+            }
+          }
+        }
+      }
+      if (operands.size !== 0) {
+        operands.add(lvalue.identifier);
+        aliases.union([...operands]);
+        // Update mutable ranges, if the ranges are empty then a reactive scope isn't created
+        for (const operand of operands) {
+          operand.mutableRange.end = makeInstructionId(instr.id + 1);
+        }
+      }
+    }
+  }
+}

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

@@ -0,0 +1,68 @@
+/**
+ * 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 {
+  HIRFunction,
+  Identifier,
+  Instruction,
+  isPrimitiveType,
+  Place,
+} from '../HIR/HIR';
+import DisjointSet from '../Utils/DisjointSet';
+
+export type AliasSet = Set<Identifier>;
+
+export function inferAliases(func: HIRFunction): DisjointSet<Identifier> {
+  const aliases = new DisjointSet<Identifier>();
+  for (const [_, block] of func.body.blocks) {
+    for (const instr of block.instructions) {
+      inferInstr(instr, aliases);
+    }
+  }
+
+  return aliases;
+}
+
+function inferInstr(
+  instr: Instruction,
+  aliases: DisjointSet<Identifier>,
+): void {
+  const {lvalue, value: instrValue} = instr;
+  let alias: Place | null = null;
+  switch (instrValue.kind) {
+    case 'LoadLocal':
+    case 'LoadContext': {
+      if (isPrimitiveType(instrValue.place.identifier)) {
+        return;
+      }
+      alias = instrValue.place;
+      break;
+    }
+    case 'StoreLocal':
+    case 'StoreContext': {
+      alias = instrValue.value;
+      break;
+    }
+    case 'Destructure': {
+      alias = instrValue.value;
+      break;
+    }
+    case 'ComputedLoad':
+    case 'PropertyLoad': {
+      alias = instrValue.object;
+      break;
+    }
+    case 'TypeCastExpression': {
+      alias = instrValue.value;
+      break;
+    }
+    default:
+      return;
+  }
+
+  aliases.union([lvalue.identifier, alias.identifier]);
+}