[eslint] Fix useEffectEvent checks in component syntax

For Edge Flight servers, that use Web Streams, we're defining the
`debugChannel` option as:

```
debugChannel?: {readable?: ReadableStream, writable?: WritableStream, ...}
```

Whereas for Node.js Flight servers, that use Node.js Streams, we're
defining it as:

```
debugChannel?: Readable | Writable | Duplex | WebSocket
```

For the Edge Flight clients, there is currently only one direction of
the debug channel supported, so we define the option as:

```
debugChannel?: {readable?: ReadableStream, ...}
```

Consequently, for the Node.js Flight clients, we define the option as:

```
debugChannel?: Readable
```

The presence of a readable debug channel is passed to the Flight client
internally via the `hasReadable` flag on the internal `debugChannel`
option. For the Node.js clients, that flag was accidentally derived from
the public option `debugChannel.readable`, which is conceptually
incorrect, because `debugChannel` is a `Readable` stream, not an options
object with a `readable` property. However, a `Readable` also has a
`readable` property, which is a boolean that indicates whether the
stream is in a readable state. This meant that the `hasReadable` flag
was incidentally still set correctly. Regardless, this was confusing and
unintentional, so we're now fixing it to always set `hasReadable` to
`true` when a `debugChannel` is provided to the Node.js clients. We'll
revisit this in case we ever add support for writable debug channels in
Node.js (and Edge) clients.

.github/workflows/runtime_commit_artifacts.yml

@@ -162,10 +162,13 @@ jobs:
           mv build/facebook-react-native/react-is/cjs/ $BASE_FOLDER/RKJSModules/vendor/react/react-is/
           mv build/facebook-react-native/react-test-renderer/cjs/ $BASE_FOLDER/RKJSModules/vendor/react/react-test-renderer/
 
-          # Delete OSS renderer. OSS renderer is synced through internal script.
+          # Delete the OSS renderers, these are sync'd to RN separately.
           RENDERER_FOLDER=$BASE_FOLDER/react-native-github/Libraries/Renderer/implementations/
           rm $RENDERER_FOLDER/ReactFabric-{dev,prod,profiling}.js
-          rm $RENDERER_FOLDER/ReactNativeRenderer-{dev,prod,profiling}.js
+          
+          # Delete the legacy renderer shim, this is not sync'd and will get deleted in the future.
+          SHIM_FOLDER=$BASE_FOLDER/react-native-github/Libraries/Renderer/shims/
+          rm $SHIM_FOLDER/ReactNative.js
 
           # Copy eslint-plugin-react-hooks
           # NOTE: This is different from www, here we include the full package

ReactVersions.js

@@ -33,7 +33,7 @@ const canaryChannelLabel = 'canary';
 const rcNumber = 0;
 
 const stablePackages = {
-  'eslint-plugin-react-hooks': '7.0.0',
+  'eslint-plugin-react-hooks': '7.1.0',
   'jest-react': '0.18.0',
   react: ReactVersion,
   'react-art': ReactVersion,

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

@@ -14,6 +14,7 @@ import React, {
   unstable_ViewTransition as ViewTransition,
   unstable_addTransitionType as addTransitionType,
   startTransition,
+  Activity,
 } from 'react';
 import {Resizable} from 're-resizable';
 import {useStore, useStoreDispatch} from '../StoreContext';
@@ -34,12 +35,8 @@ export default function ConfigEditor({
   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',
-        }}>
+      <Activity mode={isExpanded ? 'visible' : 'hidden'}>
         <ExpandedEditor
           onToggle={() => {
             startTransition(() => {
@@ -49,11 +46,8 @@ export default function ConfigEditor({
           }}
           formattedAppliedConfig={formattedAppliedConfig}
         />
-      </div>
-      <div
-        style={{
-          display: !isExpanded ? 'block' : 'none',
-        }}>
+      </Activity>
+      <Activity mode={isExpanded ? 'hidden' : 'visible'}>
         <CollapsedEditor
           onToggle={() => {
             startTransition(() => {
@@ -62,7 +56,7 @@ export default function ConfigEditor({
             });
           }}
         />
-      </div>
+      </Activity>
     </>
   );
 }
@@ -122,7 +116,8 @@ function ExpandedEditor({
 
   return (
     <ViewTransition
-      update={{[CONFIG_PANEL_TRANSITION]: 'slide-in', default: 'none'}}>
+      enter={{[CONFIG_PANEL_TRANSITION]: 'slide-in', default: 'none'}}
+      exit={{[CONFIG_PANEL_TRANSITION]: 'slide-out', default: 'none'}}>
       <Resizable
         minWidth={300}
         maxWidth={600}

compiler/apps/playground/package.json

@@ -26,8 +26,8 @@
     "@babel/traverse": "^7.18.9",
     "@babel/types": "7.26.3",
     "@heroicons/react": "^1.0.6",
-    "@monaco-editor/react": "^4.4.6",
-    "@playwright/test": "^1.51.1",
+    "@monaco-editor/react": "^4.8.0-rc.2",
+    "@playwright/test": "^1.56.1",
     "@use-gesture/react": "^10.2.22",
     "hermes-eslint": "^0.25.0",
     "hermes-parser": "^0.25.0",
@@ -40,13 +40,13 @@
     "prettier": "^3.3.3",
     "pretty-format": "^29.3.1",
     "re-resizable": "^6.9.16",
-    "react": "19.1.1",
-    "react-dom": "19.1.1"
+    "react": "19.2",
+    "react-dom": "19.2"
   },
   "devDependencies": {
     "@types/node": "18.11.9",
-    "@types/react": "19.1.13",
-    "@types/react-dom": "19.1.9",
+    "@types/react": "19.2",
+    "@types/react-dom": "19.2",
     "autoprefixer": "^10.4.13",
     "clsx": "^1.2.1",
     "concurrently": "^7.4.0",
@@ -58,7 +58,7 @@
     "wait-on": "^7.2.0"
   },
   "resolutions": {
-    "@types/react": "19.1.12",
-    "@types/react-dom": "19.1.9"
+    "@types/react": "19.2",
+    "@types/react-dom": "19.2"
   }
 }

compiler/apps/playground/styles/globals.css

@@ -79,6 +79,15 @@
 ::view-transition-group(.slide-in) {
   z-index: 1;
 }
+::view-transition-old(.slide-out) {
+  animation-name: slideOutLeft;
+}
+::view-transition-new(.slide-out) {
+  animation-name: slideInLeft;
+}
+::view-transition-group(.slide-out) {
+  z-index: 1;
+}
 
 @keyframes slideOutLeft {
   from {

compiler/apps/playground/yarn.lock

@@ -701,19 +701,19 @@
     "@jridgewell/resolve-uri" "^3.1.0"
     "@jridgewell/sourcemap-codec" "^1.4.14"
 
-"@monaco-editor/loader@^1.4.0":
-  version "1.4.0"
-  resolved "https://registry.yarnpkg.com/@monaco-editor/loader/-/loader-1.4.0.tgz#f08227057331ec890fa1e903912a5b711a2ad558"
-  integrity sha512-00ioBig0x642hytVspPl7DbQyaSWRaolYie/UFNjoTdvoKPzo6xrXLhTk9ixgIKcLH5b5vDOjVNiGyY+uDCUlg==
+"@monaco-editor/loader@^1.6.1":
+  version "1.6.1"
+  resolved "https://registry.npmjs.org/@monaco-editor/loader/-/loader-1.6.1.tgz#c99177d87765abf10de31a0086084e714acfbc0f"
+  integrity sha512-w3tEnj9HYEC73wtjdpR089AqkUPskFRcdkxsiSFt3SoUc3OHpmu+leP94CXBm4mHfefmhsdfI0ZQu6qJ0wgtPg==
   dependencies:
     state-local "^1.0.6"
 
-"@monaco-editor/react@^4.4.6":
-  version "4.6.0"
-  resolved "https://registry.yarnpkg.com/@monaco-editor/react/-/react-4.6.0.tgz#bcc68671e358a21c3814566b865a54b191e24119"
-  integrity sha512-RFkU9/i7cN2bsq/iTkurMWOEErmYcY6JiQI3Jn+WeR/FGISH8JbHERjpS9oRuSOPvDMJI0Z8nJeKkbOs9sBYQw==
+"@monaco-editor/react@^4.8.0-rc.2":
+  version "4.8.0-rc.2"
+  resolved "https://registry.npmjs.org/@monaco-editor/react/-/react-4.8.0-rc.2.tgz#e9acf652e23e9f640671a69875f496dde7f098aa"
+  integrity sha512-RzFHKBCnRA4RnozaG/EPhKsbkhX5wcApSa5MElR/AD2ojxhMY+QP+G8aJpxALCnIwKs6L0dec5MJ0nAjMUEqnA==
   dependencies:
-    "@monaco-editor/loader" "^1.4.0"
+    "@monaco-editor/loader" "^1.6.1"
 
 "@next/env@15.6.0-canary.7":
   version "15.6.0-canary.7"
@@ -798,12 +798,12 @@
   resolved "https://registry.yarnpkg.com/@pkgjs/parseargs/-/parseargs-0.11.0.tgz#a77ea742fab25775145434eb1d2328cf5013ac33"
   integrity sha512-+1VkjdD0QBLPodGrJUeqarH8VAIvQODIbwh9XpP5Syisf7YoQgsJKPNFoqqLQlu+VQ/tVSshMR6loPMn8U+dPg==
 
-"@playwright/test@^1.51.1":
-  version "1.51.1"
-  resolved "https://registry.yarnpkg.com/@playwright/test/-/test-1.51.1.tgz#75357d513221a7be0baad75f01e966baf9c41a2e"
-  integrity sha512-nM+kEaTSAoVlXmMPH10017vn3FSiFqr/bh4fKg9vmAdMfd9SDqRZNvPSiAHADc/itWak+qPvMPZQOPwCBW7k7Q==
+"@playwright/test@^1.56.1":
+  version "1.56.1"
+  resolved "https://registry.yarnpkg.com/@playwright/test/-/test-1.56.1.tgz#6e3bf3d0c90c5cf94bf64bdb56fd15a805c8bd3f"
+  integrity sha512-vSMYtL/zOcFpvJCW71Q/OEGQb7KYBPAdKh35WNSkaZA75JlAO8ED8UN6GUNTm3drWomcbcqRPFqQbLae8yBTdg==
   dependencies:
-    playwright "1.51.1"
+    playwright "1.56.1"
 
 "@rtsao/scc@^1.1.0":
   version "1.1.0"
@@ -854,22 +854,15 @@
   resolved "https://registry.yarnpkg.com/@types/node/-/node-18.11.9.tgz#02d013de7058cea16d36168ef2fc653464cfbad4"
   integrity sha512-CRpX21/kGdzjOpFsZSkcrXMGIBWMGNIHXXBVFSH+ggkftxg+XYP20TESbh+zFvFj3EQOl5byk0HTRn1IL6hbqg==
 
-"@types/react-dom@19.1.9":
-  version "19.1.9"
-  resolved "https://registry.yarnpkg.com/@types/react-dom/-/react-dom-19.1.9.tgz#5ab695fce1e804184767932365ae6569c11b4b4b"
-  integrity sha512-qXRuZaOsAdXKFyOhRBg6Lqqc0yay13vN7KrIg4L7N4aaHN68ma9OK3NE1BoDFgFOTfM7zg+3/8+2n8rLUH3OKQ==
+"@types/react-dom@19.2":
+  version "19.2.2"
+  resolved "https://registry.npmjs.org/@types/react-dom/-/react-dom-19.2.2.tgz#a4cc874797b7ddc9cb180ef0d5dc23f596fc2332"
+  integrity sha512-9KQPoO6mZCi7jcIStSnlOWn2nEF3mNmyr3rIAsGnAbQKYbRLyqmeSc39EVgtxXVia+LMT8j3knZLAZAh+xLmrw==
 
-"@types/react@19.1.12":
-  version "19.1.12"
-  resolved "https://registry.yarnpkg.com/@types/react/-/react-19.1.12.tgz#7bfaa76aabbb0b4fe0493c21a3a7a93d33e8937b"
-  integrity sha512-cMoR+FoAf/Jyq6+Df2/Z41jISvGZZ2eTlnsaJRptmZ76Caldwy1odD4xTr/gNV9VLj0AWgg/nmkevIyUfIIq5w==
-  dependencies:
-    csstype "^3.0.2"
-
-"@types/react@19.1.13":
-  version "19.1.13"
-  resolved "https://registry.yarnpkg.com/@types/react/-/react-19.1.13.tgz#fc650ffa680d739a25a530f5d7ebe00cdd771883"
-  integrity sha512-hHkbU/eoO3EG5/MZkuFSKmYqPbSVk5byPFa3e7y/8TybHiLMACgI8seVYlicwk7H5K/rI2px9xrQp/C+AUDTiQ==
+"@types/react@19.2":
+  version "19.2.2"
+  resolved "https://registry.npmjs.org/@types/react/-/react-19.2.2.tgz#ba123a75d4c2a51158697160a4ea2ff70aa6bf36"
+  integrity sha512-6mDvHUFSjyT2B2yeNx2nUgMxh9LtOWvkhIU3uePn2I2oyNymUAX1NIsdgviM4CH+JSrp2D2hsMvJOkxY+0wNRA==
   dependencies:
     csstype "^3.0.2"
 
@@ -3460,17 +3453,17 @@ pirates@^4.0.1:
   resolved "https://registry.yarnpkg.com/pirates/-/pirates-4.0.6.tgz#3018ae32ecfcff6c29ba2267cbf21166ac1f36b9"
   integrity sha512-saLsH7WeYYPiD25LDuLRRY/i+6HaPYr6G1OUlN39otzkSTxKnubR9RTxS3/Kk50s1g2JTgFwWQDQyplC5/SHZg==
 
-playwright-core@1.51.1:
-  version "1.51.1"
-  resolved "https://registry.yarnpkg.com/playwright-core/-/playwright-core-1.51.1.tgz#d57f0393e02416f32a47cf82b27533656a8acce1"
-  integrity sha512-/crRMj8+j/Nq5s8QcvegseuyeZPxpQCZb6HNk3Sos3BlZyAknRjoyJPFWkpNn8v0+P3WiwqFF8P+zQo4eqiNuw==
+playwright-core@1.56.1:
+  version "1.56.1"
+  resolved "https://registry.yarnpkg.com/playwright-core/-/playwright-core-1.56.1.tgz#24a66481e5cd33a045632230aa2c4f0cb6b1db3d"
+  integrity sha512-hutraynyn31F+Bifme+Ps9Vq59hKuUCz7H1kDOcBs+2oGguKkWTU50bBWrtz34OUWmIwpBTWDxaRPXrIXkgvmQ==
 
-playwright@1.51.1:
-  version "1.51.1"
-  resolved "https://registry.yarnpkg.com/playwright/-/playwright-1.51.1.tgz#ae1467ee318083968ad28d6990db59f47a55390f"
-  integrity sha512-kkx+MB2KQRkyxjYPc3a0wLZZoDczmppyGJIvQ43l+aZihkaVvmu/21kiyaHeHjiFxjxNNFnUncKmcGIyOojsaw==
+playwright@1.56.1:
+  version "1.56.1"
+  resolved "https://registry.yarnpkg.com/playwright/-/playwright-1.56.1.tgz#62e3b99ddebed0d475e5936a152c88e68be55fbf"
+  integrity sha512-aFi5B0WovBHTEvpM3DzXTUaeN6eN0qWnTkKx4NQaH4Wvcmc153PdaY2UBdSYKaGYw+UyWXSVyxDUg5DoPEttjw==
   dependencies:
-    playwright-core "1.51.1"
+    playwright-core "1.56.1"
   optionalDependencies:
     fsevents "2.3.2"
 
@@ -3589,12 +3582,12 @@ re-resizable@^6.9.16:
   resolved "https://registry.yarnpkg.com/re-resizable/-/re-resizable-6.10.0.tgz#d684a096ab438f1a93f59ad3a580a206b0ce31ee"
   integrity sha512-hysSK0xmA5nz24HBVztlk4yCqCLCvS32E6ZpWxVKop9x3tqCa4yAj1++facrmkOf62JsJHjmjABdKxXofYioCw==
 
-react-dom@19.1.1:
-  version "19.1.1"
-  resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-19.1.1.tgz#2daa9ff7f3ae384aeb30e76d5ee38c046dc89893"
-  integrity sha512-Dlq/5LAZgF0Gaz6yiqZCf6VCcZs1ghAJyrsu84Q/GT0gV+mCxbfmKNoGRKBYMJ8IEdGPqu49YWXD02GCknEDkw==
+react-dom@19.2:
+  version "19.2.0"
+  resolved "https://registry.npmjs.org/react-dom/-/react-dom-19.2.0.tgz#00ed1e959c365e9a9d48f8918377465466ec3af8"
+  integrity sha512-UlbRu4cAiGaIewkPyiRGJk0imDN2T3JjieT6spoL2UeSf5od4n5LB/mQ4ejmxhCFT1tYe8IvaFulzynWovsEFQ==
   dependencies:
-    scheduler "^0.26.0"
+    scheduler "^0.27.0"
 
 react-is@^16.13.1:
   version "16.13.1"
@@ -3606,10 +3599,10 @@ react-is@^18.0.0:
   resolved "https://registry.yarnpkg.com/react-is/-/react-is-18.3.1.tgz#e83557dc12eae63a99e003a46388b1dcbb44db7e"
   integrity sha512-/LLMVyas0ljjAtoYiPqYiL8VWXzUUdThrmU5+n20DZv+a+ClRoevUzw5JxU+Ieh5/c87ytoTBV9G1FiKfNJdmg==
 
-react@19.1.1:
-  version "19.1.1"
-  resolved "https://registry.yarnpkg.com/react/-/react-19.1.1.tgz#06d9149ec5e083a67f9a1e39ce97b06a03b644af"
-  integrity sha512-w8nqGImo45dmMIfljjMwOGtbmC/mk4CMYhWIicdSflH91J9TyCyczcPFXJzrZ/ZXcgGRFeP6BU0BEJTw6tZdfQ==
+react@19.2:
+  version "19.2.0"
+  resolved "https://registry.npmjs.org/react/-/react-19.2.0.tgz#d33dd1721698f4376ae57a54098cb47fc75d93a5"
+  integrity sha512-tmbWg6W31tQLeB5cdIBOicJDJRR2KzXsV7uSK9iNfLWQ5bIZfxuPEHp7M8wiHyHnn0DD1i7w3Zmin0FtkrwoCQ==
 
 read-cache@^1.0.0:
   version "1.0.0"
@@ -3785,10 +3778,10 @@ safe-regex-test@^1.1.0:
     es-errors "^1.3.0"
     is-regex "^1.2.1"
 
-scheduler@^0.26.0:
-  version "0.26.0"
-  resolved "https://registry.yarnpkg.com/scheduler/-/scheduler-0.26.0.tgz#4ce8a8c2a2095f13ea11bf9a445be50c555d6337"
-  integrity sha512-NlHwttCI/l5gCPR3D1nNXtWABUmBwvZpEQiD4IXSbIDq8BzLIK/7Ir5gTFSGZDUu37K5cMNp0hFtzO38sC7gWA==
+scheduler@^0.27.0:
+  version "0.27.0"
+  resolved "https://registry.npmjs.org/scheduler/-/scheduler-0.27.0.tgz#0c4ef82d67d1e5c1e359e8fc76d3a87f045fe5bd"
+  integrity sha512-eNv+WrVbKu1f3vbYJT/xtiF5syA5HPIMtf9IgY/nKg0sWqzAUEvqY/xm7OcZc/qafLx/iO9FgOmeSAp4v5ti/Q==
 
 semver@^6.3.1:
   version "6.3.1"

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

@@ -12,6 +12,28 @@ import {Err, Ok, Result} from './Utils/Result';
 import {assertExhaustive} from './Utils/utils';
 import invariant from 'invariant';
 
+// Number of context lines to display above the source of an error
+const CODEFRAME_LINES_ABOVE = 2;
+// Number of context lines to display below the source of an error
+const CODEFRAME_LINES_BELOW = 3;
+/*
+ * Max number of lines for the _source_ of an error, before we abbreviate
+ * the display of the source portion
+ */
+const CODEFRAME_MAX_LINES = 10;
+/*
+ * When the error source exceeds the above threshold, how many lines of
+ * the source should be displayed? We show:
+ * - CODEFRAME_LINES_ABOVE context lines
+ * - CODEFRAME_ABBREVIATED_SOURCE_LINES of the error
+ * - '...' ellipsis
+ * - CODEFRAME_ABBREVIATED_SOURCE_LINES of the error
+ * - CODEFRAME_LINES_BELOW context lines
+ *
+ * This value must be at least 2 or else we'll cut off important parts of the error message
+ */
+const CODEFRAME_ABBREVIATED_SOURCE_LINES = 5;
+
 export enum ErrorSeverity {
   /**
    * An actionable error that the developer can fix. For example, product code errors should be
@@ -496,7 +518,7 @@ function printCodeFrame(
   loc: t.SourceLocation,
   message: string,
 ): string {
-  return codeFrameColumns(
+  const printed = codeFrameColumns(
     source,
     {
       start: {
@@ -510,8 +532,25 @@ function printCodeFrame(
     },
     {
       message,
+      linesAbove: CODEFRAME_LINES_ABOVE,
+      linesBelow: CODEFRAME_LINES_BELOW,
     },
   );
+  const lines = printed.split(/\r?\n/);
+  if (loc.end.line - loc.start.line < CODEFRAME_MAX_LINES) {
+    return printed;
+  }
+  const pipeIndex = lines[0].indexOf('|');
+  return [
+    ...lines.slice(
+      0,
+      CODEFRAME_LINES_ABOVE + CODEFRAME_ABBREVIATED_SOURCE_LINES,
+    ),
+    ' '.repeat(pipeIndex) + '…',
+    ...lines.slice(
+      -(CODEFRAME_LINES_BELOW + CODEFRAME_ABBREVIATED_SOURCE_LINES),
+    ),
+  ].join('\n');
 }
 
 function printErrorSummary(category: ErrorCategory, message: string): string {

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

@@ -103,6 +103,7 @@ import {validateNoFreezingKnownMutableFunctions} from '../Validation/ValidateNoF
 import {inferMutationAliasingEffects} from '../Inference/InferMutationAliasingEffects';
 import {inferMutationAliasingRanges} from '../Inference/InferMutationAliasingRanges';
 import {validateNoDerivedComputationsInEffects} from '../Validation/ValidateNoDerivedComputationsInEffects';
+import {validateNoDerivedComputationsInEffects_exp} from '../Validation/ValidateNoDerivedComputationsInEffects_exp';
 import {nameAnonymousFunctions} from '../Transform/NameAnonymousFunctions';
 
 export type CompilerPipelineValue =
@@ -275,6 +276,10 @@ function runWithEnvironment(
       validateNoDerivedComputationsInEffects(hir);
     }
 
+    if (env.config.validateNoDerivedComputationsInEffects_exp) {
+      validateNoDerivedComputationsInEffects_exp(hir);
+    }
+
     if (env.config.validateNoSetStateInEffects) {
       env.logErrors(validateNoSetStateInEffects(hir, env));
     }

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

@@ -1568,20 +1568,6 @@ function lowerObjectPropertyKey(
       name: key.node.value,
     };
   } else if (property.node.computed && key.isExpression()) {
-    if (!key.isIdentifier() && !key.isMemberExpression()) {
-      /*
-       * NOTE: allowing complex key expressions can trigger a bug where a mutation is made conditional
-       * see fixture
-       * error.object-expression-computed-key-modified-during-after-construction.js
-       */
-      builder.errors.push({
-        reason: `(BuildHIR::lowerExpression) Expected Identifier, got ${key.type} key in ObjectExpression`,
-        category: ErrorCategory.Todo,
-        loc: key.node.loc ?? null,
-        suggestions: null,
-      });
-      return null;
-    }
     const place = lowerExpressionToTemporary(builder, key);
     return {
       kind: 'computed',

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

@@ -83,21 +83,11 @@ export type ExternalFunction = z.infer<typeof ExternalFunctionSchema>;
 export const USE_FIRE_FUNCTION_NAME = 'useFire';
 export const EMIT_FREEZE_GLOBAL_GATING = '__DEV__';
 
-export const MacroMethodSchema = z.union([
-  z.object({type: z.literal('wildcard')}),
-  z.object({type: z.literal('name'), name: z.string()}),
-]);
-
-// Would like to change this to drop the string option, but breaks compatibility with existing configs
-export const MacroSchema = z.union([
-  z.string(),
-  z.tuple([z.string(), z.array(MacroMethodSchema)]),
-]);
+export const MacroSchema = z.string();
 
 export type CompilerMode = 'all_features' | 'no_inferred_memo';
 
 export type Macro = z.infer<typeof MacroSchema>;
-export type MacroMethod = z.infer<typeof MacroMethodSchema>;
 
 const HookSchema = z.object({
   /*
@@ -334,6 +324,12 @@ export const EnvironmentConfigSchema = z.object({
    */
   validateNoDerivedComputationsInEffects: z.boolean().default(false),
 
+  /**
+   * Experimental: Validates that effects are not used to calculate derived data which could instead be computed
+   * during render. Generates a custom error message for each type of violation.
+   */
+  validateNoDerivedComputationsInEffects_exp: z.boolean().default(false),
+
   /**
    * Validates against creating JSX within a try block and recommends using an error boundary
    * instead.

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

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

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

@@ -11,6 +11,7 @@ import {
   CallExpression,
   Effect,
   Environment,
+  FinishMemoize,
   FunctionExpression,
   HIRFunction,
   IdentifierId,
@@ -24,6 +25,7 @@ import {
   Place,
   PropertyLoad,
   SpreadPattern,
+  StartMemoize,
   TInstruction,
   getHookKindForType,
   makeInstructionId,
@@ -182,52 +184,36 @@ function makeManualMemoizationMarkers(
   depsList: Array<ManualMemoDependency> | null,
   memoDecl: Place,
   manualMemoId: number,
-): [Array<Instruction>, Array<Instruction>] {
-  const temp = createTemporaryPlace(env, memoDecl.loc);
+): [TInstruction<StartMemoize>, TInstruction<FinishMemoize>] {
   return [
-    [
-      {
-        id: makeInstructionId(0),
-        lvalue: createTemporaryPlace(env, fnExpr.loc),
-        value: {
-          kind: 'StartMemoize',
-          manualMemoId,
-          /*
-           * Use deps list from source instead of inferred deps
-           * as dependencies
-           */
-          deps: depsList,
-          loc: fnExpr.loc,
-        },
-        effects: null,
+    {
+      id: makeInstructionId(0),
+      lvalue: createTemporaryPlace(env, fnExpr.loc),
+      value: {
+        kind: 'StartMemoize',
+        manualMemoId,
+        /*
+         * Use deps list from source instead of inferred deps
+         * as dependencies
+         */
+        deps: depsList,
         loc: fnExpr.loc,
       },
-    ],
-    [
-      {
-        id: makeInstructionId(0),
-        lvalue: {...temp},
-        value: {
-          kind: 'LoadLocal',
-          place: {...memoDecl},
-          loc: memoDecl.loc,
-        },
-        effects: null,
-        loc: memoDecl.loc,
+      effects: null,
+      loc: fnExpr.loc,
+    },
+    {
+      id: makeInstructionId(0),
+      lvalue: createTemporaryPlace(env, fnExpr.loc),
+      value: {
+        kind: 'FinishMemoize',
+        manualMemoId,
+        decl: {...memoDecl},
+        loc: fnExpr.loc,
       },
-      {
-        id: makeInstructionId(0),
-        lvalue: createTemporaryPlace(env, memoDecl.loc),
-        value: {
-          kind: 'FinishMemoize',
-          manualMemoId,
-          decl: {...temp},
-          loc: memoDecl.loc,
-        },
-        effects: null,
-        loc: memoDecl.loc,
-      },
-    ],
+      effects: null,
+      loc: fnExpr.loc,
+    },
   ];
 }
 
@@ -423,7 +409,10 @@ export function dropManualMemoization(
    *   LoadLocal fnArg
    * - (if validation is enabled) collect manual memoization markers
    */
-  const queuedInserts: Map<InstructionId, Array<Instruction>> = new Map();
+  const queuedInserts: Map<
+    InstructionId,
+    TInstruction<StartMemoize> | TInstruction<FinishMemoize>
+  > = new Map();
   for (const [_, block] of func.body.blocks) {
     for (let i = 0; i < block.instructions.length; i++) {
       const instr = block.instructions[i]!;
@@ -534,11 +523,11 @@ export function dropManualMemoization(
       let nextInstructions: Array<Instruction> | null = null;
       for (let i = 0; i < block.instructions.length; i++) {
         const instr = block.instructions[i];
-        const insertInstructions = queuedInserts.get(instr.id);
-        if (insertInstructions != null) {
+        const insertInstr = queuedInserts.get(instr.id);
+        if (insertInstr != null) {
           nextInstructions = nextInstructions ?? block.instructions.slice(0, i);
           nextInstructions.push(instr);
-          nextInstructions.push(...insertInstructions);
+          nextInstructions.push(insertInstr);
         } else if (nextInstructions != null) {
           nextInstructions.push(instr);
         }

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

@@ -19,6 +19,7 @@ import {
   Environment,
   FunctionExpression,
   GeneratedSource,
+  getHookKind,
   HIRFunction,
   Hole,
   IdentifierId,
@@ -198,6 +199,7 @@ export function inferMutationAliasingEffects(
     isFunctionExpression,
     fn,
     hoistedContextDeclarations,
+    findNonMutatedDestructureSpreads(fn),
   );
 
   let iterationCount = 0;
@@ -287,15 +289,18 @@ class Context {
   isFuctionExpression: boolean;
   fn: HIRFunction;
   hoistedContextDeclarations: Map<DeclarationId, Place | null>;
+  nonMutatingSpreads: Set<IdentifierId>;
 
   constructor(
     isFunctionExpression: boolean,
     fn: HIRFunction,
     hoistedContextDeclarations: Map<DeclarationId, Place | null>,
+    nonMutatingSpreads: Set<IdentifierId>,
   ) {
     this.isFuctionExpression = isFunctionExpression;
     this.fn = fn;
     this.hoistedContextDeclarations = hoistedContextDeclarations;
+    this.nonMutatingSpreads = nonMutatingSpreads;
   }
 
   cacheApplySignature(
@@ -322,6 +327,161 @@ class Context {
   }
 }
 
+/**
+ * Finds objects created via ObjectPattern spread destructuring
+ * (`const {x, ...spread} = ...`) where a) the rvalue is known frozen and
+ * b) the spread value cannot possibly be directly mutated. The idea is that
+ * for this set of values, we can treat the spread object as frozen.
+ *
+ * The primary use case for this is props spreading:
+ *
+ * ```
+ * function Component({prop, ...otherProps}) {
+ *   const transformedProp = transform(prop, otherProps.foo);
+ *   // pass `otherProps` down:
+ *   return <Foo {...otherProps} prop={transformedProp} />;
+ * }
+ * ```
+ *
+ * Here we know that since `otherProps` cannot be mutated, we don't have to treat
+ * it as mutable: `otherProps.foo` only reads a value that must be frozen, so it
+ * can be treated as frozen too.
+ */
+function findNonMutatedDestructureSpreads(fn: HIRFunction): Set<IdentifierId> {
+  const knownFrozen = new Set<IdentifierId>();
+  if (fn.fnType === 'Component') {
+    const [props] = fn.params;
+    if (props != null && props.kind === 'Identifier') {
+      knownFrozen.add(props.identifier.id);
+    }
+  } else {
+    for (const param of fn.params) {
+      if (param.kind === 'Identifier') {
+        knownFrozen.add(param.identifier.id);
+      }
+    }
+  }
+
+  // Map of temporaries to identifiers for spread objects
+  const candidateNonMutatingSpreads = new Map<IdentifierId, IdentifierId>();
+  for (const block of fn.body.blocks.values()) {
+    if (candidateNonMutatingSpreads.size !== 0) {
+      for (const phi of block.phis) {
+        for (const operand of phi.operands.values()) {
+          const spread = candidateNonMutatingSpreads.get(operand.identifier.id);
+          if (spread != null) {
+            candidateNonMutatingSpreads.delete(spread);
+          }
+        }
+      }
+    }
+    for (const instr of block.instructions) {
+      const {lvalue, value} = instr;
+      switch (value.kind) {
+        case 'Destructure': {
+          if (
+            !knownFrozen.has(value.value.identifier.id) ||
+            !(
+              value.lvalue.kind === InstructionKind.Let ||
+              value.lvalue.kind === InstructionKind.Const
+            ) ||
+            value.lvalue.pattern.kind !== 'ObjectPattern'
+          ) {
+            continue;
+          }
+          for (const item of value.lvalue.pattern.properties) {
+            if (item.kind !== 'Spread') {
+              continue;
+            }
+            candidateNonMutatingSpreads.set(
+              item.place.identifier.id,
+              item.place.identifier.id,
+            );
+          }
+          break;
+        }
+        case 'LoadLocal': {
+          const spread = candidateNonMutatingSpreads.get(
+            value.place.identifier.id,
+          );
+          if (spread != null) {
+            candidateNonMutatingSpreads.set(lvalue.identifier.id, spread);
+          }
+          break;
+        }
+        case 'StoreLocal': {
+          const spread = candidateNonMutatingSpreads.get(
+            value.value.identifier.id,
+          );
+          if (spread != null) {
+            candidateNonMutatingSpreads.set(lvalue.identifier.id, spread);
+            candidateNonMutatingSpreads.set(
+              value.lvalue.place.identifier.id,
+              spread,
+            );
+          }
+          break;
+        }
+        case 'JsxFragment':
+        case 'JsxExpression': {
+          // Passing objects created with spread to jsx can't mutate them
+          break;
+        }
+        case 'PropertyLoad': {
+          // Properties must be frozen since the original value was frozen
+          break;
+        }
+        case 'CallExpression':
+        case 'MethodCall': {
+          const callee =
+            value.kind === 'CallExpression' ? value.callee : value.property;
+          if (getHookKind(fn.env, callee.identifier) != null) {
+            // Hook calls have frozen arguments, and non-ref returns are frozen
+            if (!isRefOrRefValue(lvalue.identifier)) {
+              knownFrozen.add(lvalue.identifier.id);
+            }
+          } else {
+            // Non-hook calls check their operands, since they are potentially mutable
+            if (candidateNonMutatingSpreads.size !== 0) {
+              // Otherwise any reference to the spread object itself may mutate
+              for (const operand of eachInstructionValueOperand(value)) {
+                const spread = candidateNonMutatingSpreads.get(
+                  operand.identifier.id,
+                );
+                if (spread != null) {
+                  candidateNonMutatingSpreads.delete(spread);
+                }
+              }
+            }
+          }
+          break;
+        }
+        default: {
+          if (candidateNonMutatingSpreads.size !== 0) {
+            // Otherwise any reference to the spread object itself may mutate
+            for (const operand of eachInstructionValueOperand(value)) {
+              const spread = candidateNonMutatingSpreads.get(
+                operand.identifier.id,
+              );
+              if (spread != null) {
+                candidateNonMutatingSpreads.delete(spread);
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  const nonMutatingSpreads = new Set<IdentifierId>();
+  for (const [key, value] of candidateNonMutatingSpreads) {
+    if (key === value) {
+      nonMutatingSpreads.add(key);
+    }
+  }
+  return nonMutatingSpreads;
+}
+
 function inferParam(
   param: Place | SpreadPattern,
   initialState: InferenceState,
@@ -2054,7 +2214,9 @@ function computeSignatureForInstruction(
             kind: 'Create',
             into: place,
             reason: ValueReason.Other,
-            value: ValueKind.Mutable,
+            value: context.nonMutatingSpreads.has(place.identifier.id)
+              ? ValueKind.Frozen
+              : ValueKind.Mutable,
           });
           effects.push({
             kind: 'Capture',

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

@@ -7,7 +7,6 @@
 
 import {
   HIRFunction,
-  Identifier,
   IdentifierId,
   InstructionValue,
   makeInstructionId,
@@ -15,9 +14,35 @@ import {
   Place,
   ReactiveScope,
 } from '../HIR';
-import {Macro, MacroMethod} from '../HIR/Environment';
+import {Macro} from '../HIR/Environment';
 import {eachInstructionValueOperand} from '../HIR/visitors';
-import {Iterable_some} from '../Utils/utils';
+
+/**
+ * Whether a macro requires its arguments to be transitively inlined (eg fbt)
+ * or just avoid having the top-level values be converted to variables (eg fbt.param)
+ */
+enum InlineLevel {
+  Transitive = 'Transitive',
+  Shallow = 'Shallow',
+}
+type MacroDefinition = {
+  level: InlineLevel;
+  properties: Map<string, MacroDefinition> | null;
+};
+
+const SHALLOW_MACRO: MacroDefinition = {
+  level: InlineLevel.Shallow,
+  properties: null,
+};
+const TRANSITIVE_MACRO: MacroDefinition = {
+  level: InlineLevel.Transitive,
+  properties: null,
+};
+const FBT_MACRO: MacroDefinition = {
+  level: InlineLevel.Transitive,
+  properties: new Map([['*', SHALLOW_MACRO]]),
+};
+FBT_MACRO.properties!.set('enum', FBT_MACRO);
 
 /**
  * This pass supports the `fbt` translation system (https://facebook.github.io/fbt/)
@@ -42,250 +67,210 @@ import {Iterable_some} from '../Utils/utils';
  * ## User-defined macro-like function
  *
  * Users can also specify their own functions to be treated similarly to fbt via the
- * `customMacros` environment configuration.
+ * `customMacros` environment configuration. By default, user-supplied custom macros
+ * have their arguments transitively inlined.
  */
 export function memoizeFbtAndMacroOperandsInSameScope(
   fn: HIRFunction,
 ): Set<IdentifierId> {
-  const fbtMacroTags = new Set<Macro>([
-    ...Array.from(FBT_TAGS).map((tag): Macro => [tag, []]),
-    ...(fn.env.config.customMacros ?? []),
+  const macroKinds = new Map<Macro, MacroDefinition>([
+    ...Array.from(FBT_TAGS.entries()),
+    ...(fn.env.config.customMacros ?? []).map(
+      name => [name, TRANSITIVE_MACRO] as [Macro, MacroDefinition],
+    ),
   ]);
   /**
-   * Set of all identifiers that load fbt or other macro functions or their nested
-   * properties, as well as values known to be the results of invoking macros
+   * Forward data-flow analysis to identify all macro tags, including
+   * things like `fbt.foo.bar(...)`
    */
-  const macroTagsCalls: Set<IdentifierId> = new Set();
+  const macroTags = populateMacroTags(fn, macroKinds);
+
   /**
-   * Mapping of lvalue => list of operands for all expressions where either
-   * the lvalue is a known fbt/macro call and/or the operands transitively
-   * contain fbt/macro calls.
-   *
-   * This is the key data structure that powers the scope merging: we start
-   * at the lvalues and merge operands into the lvalue's scope.
+   * Reverse data-flow analysis to merge arguments to macro *invocations*
+   * based on the kind of the macro
    */
-  const macroValues: Map<Identifier, Array<Identifier>> = new Map();
-  // Tracks methods loaded from macros, like fbt.param or idx.foo
-  const macroMethods = new Map<IdentifierId, Array<Array<MacroMethod>>>();
+  const macroValues = mergeMacroArguments(fn, macroTags, macroKinds);
 
-  visit(fn, fbtMacroTags, macroTagsCalls, macroMethods, macroValues);
-
-  for (const root of macroValues.keys()) {
-    const scope = root.scope;
-    if (scope == null) {
-      continue;
-    }
-    // Merge the operands into the same scope if this is a known macro invocation
-    if (!macroTagsCalls.has(root.id)) {
-      continue;
-    }
-    mergeScopes(root, scope, macroValues, macroTagsCalls);
-  }
-
-  return macroTagsCalls;
+  return macroValues;
 }
 
-export const FBT_TAGS: Set<string> = new Set([
-  'fbt',
-  'fbt:param',
-  'fbt:enum',
-  'fbt:plural',
-  'fbs',
-  'fbs:param',
-  'fbs:enum',
-  'fbs:plural',
+const FBT_TAGS: Map<string, MacroDefinition> = new Map([
+  ['fbt', FBT_MACRO],
+  ['fbt:param', SHALLOW_MACRO],
+  ['fbt:enum', FBT_MACRO],
+  ['fbt:plural', SHALLOW_MACRO],
+  ['fbs', FBT_MACRO],
+  ['fbs:param', SHALLOW_MACRO],
+  ['fbs:enum', FBT_MACRO],
+  ['fbs:plural', SHALLOW_MACRO],
 ]);
 export const SINGLE_CHILD_FBT_TAGS: Set<string> = new Set([
   'fbt:param',
   'fbs:param',
 ]);
 
-function visit(
+function populateMacroTags(
   fn: HIRFunction,
-  fbtMacroTags: Set<Macro>,
-  macroTagsCalls: Set<IdentifierId>,
-  macroMethods: Map<IdentifierId, Array<Array<MacroMethod>>>,
-  macroValues: Map<Identifier, Array<Identifier>>,
-): void {
-  for (const [, block] of fn.body.blocks) {
-    for (const phi of block.phis) {
-      const macroOperands: Array<Identifier> = [];
-      for (const operand of phi.operands.values()) {
-        if (macroValues.has(operand.identifier)) {
-          macroOperands.push(operand.identifier);
-        }
-      }
-      if (macroOperands.length !== 0) {
-        macroValues.set(phi.place.identifier, macroOperands);
-      }
-    }
-    for (const instruction of block.instructions) {
-      const {lvalue, value} = instruction;
-      if (lvalue === null) {
-        continue;
-      }
-      if (
-        value.kind === 'Primitive' &&
-        typeof value.value === 'string' &&
-        matchesExactTag(value.value, fbtMacroTags)
-      ) {
-        /*
-         * We don't distinguish between tag names and strings, so record
-         * all `fbt` string literals in case they are used as a jsx tag.
-         */
-        macroTagsCalls.add(lvalue.identifier.id);
-      } else if (
-        value.kind === 'LoadGlobal' &&
-        matchesExactTag(value.binding.name, fbtMacroTags)
-      ) {
-        // Record references to `fbt` as a global
-        macroTagsCalls.add(lvalue.identifier.id);
-      } else if (
-        value.kind === 'LoadGlobal' &&
-        matchTagRoot(value.binding.name, fbtMacroTags) !== null
-      ) {
-        const methods = matchTagRoot(value.binding.name, fbtMacroTags)!;
-        macroMethods.set(lvalue.identifier.id, methods);
-      } else if (
-        value.kind === 'PropertyLoad' &&
-        macroMethods.has(value.object.identifier.id)
-      ) {
-        const methods = macroMethods.get(value.object.identifier.id)!;
-        const newMethods = [];
-        for (const method of methods) {
-          if (
-            method.length > 0 &&
-            (method[0].type === 'wildcard' ||
-              (method[0].type === 'name' && method[0].name === value.property))
-          ) {
-            if (method.length > 1) {
-              newMethods.push(method.slice(1));
-            } else {
-              macroTagsCalls.add(lvalue.identifier.id);
+  macroKinds: Map<Macro, MacroDefinition>,
+): Map<IdentifierId, MacroDefinition> {
+  const macroTags = new Map<IdentifierId, MacroDefinition>();
+  for (const block of fn.body.blocks.values()) {
+    for (const instr of block.instructions) {
+      const {lvalue, value} = instr;
+      switch (value.kind) {
+        case 'Primitive': {
+          if (typeof value.value === 'string') {
+            const macroDefinition = macroKinds.get(value.value);
+            if (macroDefinition != null) {
+              /*
+               * We don't distinguish between tag names and strings, so record
+               * all `fbt` string literals in case they are used as a jsx tag.
+               */
+              macroTags.set(lvalue.identifier.id, macroDefinition);
             }
           }
+          break;
         }
-        if (newMethods.length > 0) {
-          macroMethods.set(lvalue.identifier.id, newMethods);
-        }
-      } else if (
-        value.kind === 'PropertyLoad' &&
-        macroTagsCalls.has(value.object.identifier.id)
-      ) {
-        macroTagsCalls.add(lvalue.identifier.id);
-      } else if (
-        isFbtJsxExpression(fbtMacroTags, macroTagsCalls, value) ||
-        isFbtJsxChild(macroTagsCalls, lvalue, value) ||
-        isFbtCallExpression(macroTagsCalls, value)
-      ) {
-        macroTagsCalls.add(lvalue.identifier.id);
-        macroValues.set(
-          lvalue.identifier,
-          Array.from(
-            eachInstructionValueOperand(value),
-            operand => operand.identifier,
-          ),
-        );
-      } else if (
-        Iterable_some(eachInstructionValueOperand(value), operand =>
-          macroValues.has(operand.identifier),
-        )
-      ) {
-        const macroOperands: Array<Identifier> = [];
-        for (const operand of eachInstructionValueOperand(value)) {
-          if (macroValues.has(operand.identifier)) {
-            macroOperands.push(operand.identifier);
+        case 'LoadGlobal': {
+          let macroDefinition = macroKinds.get(value.binding.name);
+          if (macroDefinition != null) {
+            macroTags.set(lvalue.identifier.id, macroDefinition);
           }
+          break;
+        }
+        case 'PropertyLoad': {
+          if (typeof value.property === 'string') {
+            const macroDefinition = macroTags.get(value.object.identifier.id);
+            if (macroDefinition != null) {
+              const propertyDefinition =
+                macroDefinition.properties != null
+                  ? (macroDefinition.properties.get(value.property) ??
+                    macroDefinition.properties.get('*'))
+                  : null;
+              const propertyMacro = propertyDefinition ?? macroDefinition;
+              macroTags.set(lvalue.identifier.id, propertyMacro);
+            }
+          }
+          break;
         }
-        macroValues.set(lvalue.identifier, macroOperands);
       }
     }
   }
+  return macroTags;
 }
 
-function mergeScopes(
-  root: Identifier,
-  scope: ReactiveScope,
-  macroValues: Map<Identifier, Array<Identifier>>,
-  macroTagsCalls: Set<IdentifierId>,
-): void {
-  const operands = macroValues.get(root);
-  if (operands == null) {
-    return;
-  }
-  for (const operand of operands) {
-    operand.scope = scope;
-    expandFbtScopeRange(scope.range, operand.mutableRange);
-    macroTagsCalls.add(operand.id);
-    mergeScopes(operand, scope, macroValues, macroTagsCalls);
-  }
-}
-
-function matchesExactTag(s: string, tags: Set<Macro>): boolean {
-  return Array.from(tags).some(macro =>
-    typeof macro === 'string'
-      ? s === macro
-      : macro[1].length === 0 && macro[0] === s,
-  );
-}
-
-function matchTagRoot(
-  s: string,
-  tags: Set<Macro>,
-): Array<Array<MacroMethod>> | null {
-  const methods: Array<Array<MacroMethod>> = [];
-  for (const macro of tags) {
-    if (typeof macro === 'string') {
-      continue;
+function mergeMacroArguments(
+  fn: HIRFunction,
+  macroTags: Map<IdentifierId, MacroDefinition>,
+  macroKinds: Map<Macro, MacroDefinition>,
+): Set<IdentifierId> {
+  const macroValues = new Set<IdentifierId>(macroTags.keys());
+  for (const block of Array.from(fn.body.blocks.values()).reverse()) {
+    for (let i = block.instructions.length - 1; i >= 0; i--) {
+      const instr = block.instructions[i]!;
+      const {lvalue, value} = instr;
+      switch (value.kind) {
+        case 'DeclareContext':
+        case 'DeclareLocal':
+        case 'Destructure':
+        case 'LoadContext':
+        case 'LoadLocal':
+        case 'PostfixUpdate':
+        case 'PrefixUpdate':
+        case 'StoreContext':
+        case 'StoreLocal': {
+          // Instructions that never need to be merged
+          break;
+        }
+        case 'CallExpression':
+        case 'MethodCall': {
+          const scope = lvalue.identifier.scope;
+          if (scope == null) {
+            continue;
+          }
+          const callee =
+            value.kind === 'CallExpression' ? value.callee : value.property;
+          const macroDefinition =
+            macroTags.get(callee.identifier.id) ??
+            macroTags.get(lvalue.identifier.id);
+          if (macroDefinition != null) {
+            visitOperands(
+              macroDefinition,
+              scope,
+              lvalue,
+              value,
+              macroValues,
+              macroTags,
+            );
+          }
+          break;
+        }
+        case 'JsxExpression': {
+          const scope = lvalue.identifier.scope;
+          if (scope == null) {
+            continue;
+          }
+          let macroDefinition;
+          if (value.tag.kind === 'Identifier') {
+            macroDefinition = macroTags.get(value.tag.identifier.id);
+          } else {
+            macroDefinition = macroKinds.get(value.tag.name);
+          }
+          macroDefinition ??= macroTags.get(lvalue.identifier.id);
+          if (macroDefinition != null) {
+            visitOperands(
+              macroDefinition,
+              scope,
+              lvalue,
+              value,
+              macroValues,
+              macroTags,
+            );
+          }
+          break;
+        }
+        default: {
+          const scope = lvalue.identifier.scope;
+          if (scope == null) {
+            continue;
+          }
+          const macroDefinition = macroTags.get(lvalue.identifier.id);
+          if (macroDefinition != null) {
+            visitOperands(
+              macroDefinition,
+              scope,
+              lvalue,
+              value,
+              macroValues,
+              macroTags,
+            );
+          }
+          break;
+        }
+      }
     }
-    const [tag, rest] = macro;
-    if (tag === s && rest.length > 0) {
-      methods.push(rest);
+    for (const phi of block.phis) {
+      const scope = phi.place.identifier.scope;
+      if (scope == null) {
+        continue;
+      }
+      const macroDefinition = macroTags.get(phi.place.identifier.id);
+      if (
+        macroDefinition == null ||
+        macroDefinition.level === InlineLevel.Shallow
+      ) {
+        continue;
+      }
+      macroValues.add(phi.place.identifier.id);
+      for (const operand of phi.operands.values()) {
+        operand.identifier.scope = scope;
+        expandFbtScopeRange(scope.range, operand.identifier.mutableRange);
+        macroTags.set(operand.identifier.id, macroDefinition);
+        macroValues.add(operand.identifier.id);
+      }
     }
   }
-  if (methods.length > 0) {
-    return methods;
-  } else {
-    return null;
-  }
-}
-
-function isFbtCallExpression(
-  macroTagsCalls: Set<IdentifierId>,
-  value: InstructionValue,
-): boolean {
-  return (
-    (value.kind === 'CallExpression' &&
-      macroTagsCalls.has(value.callee.identifier.id)) ||
-    (value.kind === 'MethodCall' &&
-      macroTagsCalls.has(value.property.identifier.id))
-  );
-}
-
-function isFbtJsxExpression(
-  fbtMacroTags: Set<Macro>,
-  macroTagsCalls: Set<IdentifierId>,
-  value: InstructionValue,
-): boolean {
-  return (
-    value.kind === 'JsxExpression' &&
-    ((value.tag.kind === 'Identifier' &&
-      macroTagsCalls.has(value.tag.identifier.id)) ||
-      (value.tag.kind === 'BuiltinTag' &&
-        matchesExactTag(value.tag.name, fbtMacroTags)))
-  );
-}
-
-function isFbtJsxChild(
-  macroTagsCalls: Set<IdentifierId>,
-  lvalue: Place | null,
-  value: InstructionValue,
-): boolean {
-  return (
-    (value.kind === 'JsxExpression' || value.kind === 'JsxFragment') &&
-    lvalue !== null &&
-    macroTagsCalls.has(lvalue.identifier.id)
-  );
+  return macroValues;
 }
 
 function expandFbtScopeRange(
@@ -298,3 +283,22 @@ function expandFbtScopeRange(
     );
   }
 }
+
+function visitOperands(
+  macroDefinition: MacroDefinition,
+  scope: ReactiveScope,
+  lvalue: Place,
+  value: InstructionValue,
+  macroValues: Set<IdentifierId>,
+  macroTags: Map<IdentifierId, MacroDefinition>,
+): void {
+  macroValues.add(lvalue.identifier.id);
+  for (const operand of eachInstructionValueOperand(value)) {
+    if (macroDefinition.level === InlineLevel.Transitive) {
+      operand.identifier.scope = scope;
+      expandFbtScopeRange(scope.range, operand.identifier.mutableRange);
+      macroTags.set(operand.identifier.id, macroDefinition);
+    }
+    macroValues.add(operand.identifier.id);
+  }
+}

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

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

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

@@ -135,16 +135,7 @@ function parseConfigPragmaEnvironmentForTest(
     } else if (val) {
       const parsedVal = tryParseTestPragmaValue(val).unwrap();
       if (key === 'customMacros' && typeof parsedVal === 'string') {
-        const valSplit = parsedVal.split('.');
-        const props = [];
-        for (const elt of valSplit.slice(1)) {
-          if (elt === '*') {
-            props.push({type: 'wildcard'});
-          } else if (elt.length > 0) {
-            props.push({type: 'name', name: elt});
-          }
-        }
-        maybeConfig[key] = [[valSplit[0], props]];
+        maybeConfig[key] = [parsedVal.split('.')[0]];
         continue;
       }
       maybeConfig[key] = parsedVal;

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

@@ -0,0 +1,504 @@
+/**
+ * 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, CompilerError, Effect} from '..';
+import {ErrorCategory} from '../CompilerError';
+import {
+  BlockId,
+  FunctionExpression,
+  HIRFunction,
+  IdentifierId,
+  isSetStateType,
+  isUseEffectHookType,
+  Place,
+  CallExpression,
+  Instruction,
+  isUseStateType,
+  BasicBlock,
+  isUseRefType,
+  GeneratedSource,
+  SourceLocation,
+} from '../HIR';
+import {eachInstructionLValue, eachInstructionOperand} from '../HIR/visitors';
+import {isMutable} from '../ReactiveScopes/InferReactiveScopeVariables';
+import {assertExhaustive} from '../Utils/utils';
+
+type TypeOfValue = 'ignored' | 'fromProps' | 'fromState' | 'fromPropsAndState';
+
+type DerivationMetadata = {
+  typeOfValue: TypeOfValue;
+  place: Place;
+  sourcesIds: Set<IdentifierId>;
+};
+
+type ValidationContext = {
+  readonly functions: Map<IdentifierId, FunctionExpression>;
+  readonly errors: CompilerError;
+  readonly derivationCache: DerivationCache;
+  readonly effects: Set<HIRFunction>;
+  readonly setStateCache: Map<string | undefined | null, Array<Place>>;
+  readonly effectSetStateCache: Map<string | undefined | null, Array<Place>>;
+};
+
+class DerivationCache {
+  hasChanges: boolean = false;
+  cache: Map<IdentifierId, DerivationMetadata> = new Map();
+
+  snapshot(): boolean {
+    const hasChanges = this.hasChanges;
+    this.hasChanges = false;
+    return hasChanges;
+  }
+
+  addDerivationEntry(
+    derivedVar: Place,
+    sourcesIds: Set<IdentifierId>,
+    typeOfValue: TypeOfValue,
+  ): void {
+    let newValue: DerivationMetadata = {
+      place: derivedVar,
+      sourcesIds: new Set(),
+      typeOfValue: typeOfValue ?? 'ignored',
+    };
+
+    if (sourcesIds !== undefined) {
+      for (const id of sourcesIds) {
+        const sourcePlace = this.cache.get(id)?.place;
+
+        if (sourcePlace === undefined) {
+          continue;
+        }
+
+        /*
+         * If the identifier of the source is a promoted identifier, then
+         *  we should set the target as the source.
+         */
+        if (
+          sourcePlace.identifier.name === null ||
+          sourcePlace.identifier.name?.kind === 'promoted'
+        ) {
+          newValue.sourcesIds.add(derivedVar.identifier.id);
+        } else {
+          newValue.sourcesIds.add(sourcePlace.identifier.id);
+        }
+      }
+    }
+
+    if (newValue.sourcesIds.size === 0) {
+      newValue.sourcesIds.add(derivedVar.identifier.id);
+    }
+
+    const existingValue = this.cache.get(derivedVar.identifier.id);
+    if (
+      existingValue === undefined ||
+      !this.isDerivationEqual(existingValue, newValue)
+    ) {
+      this.cache.set(derivedVar.identifier.id, newValue);
+      this.hasChanges = true;
+    }
+  }
+
+  private isDerivationEqual(
+    a: DerivationMetadata,
+    b: DerivationMetadata,
+  ): boolean {
+    if (a.typeOfValue !== b.typeOfValue) {
+      return false;
+    }
+    if (a.sourcesIds.size !== b.sourcesIds.size) {
+      return false;
+    }
+    for (const id of a.sourcesIds) {
+      if (!b.sourcesIds.has(id)) {
+        return false;
+      }
+    }
+    return true;
+  }
+}
+
+/**
+ * Validates that useEffect is not used for derived computations which could/should
+ * be performed in render.
+ *
+ * See https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state
+ *
+ * Example:
+ *
+ * ```
+ * // 🔴 Avoid: redundant state and unnecessary Effect
+ * const [fullName, setFullName] = useState('');
+ * useEffect(() => {
+ *   setFullName(firstName + ' ' + lastName);
+ * }, [firstName, lastName]);
+ * ```
+ *
+ * Instead use:
+ *
+ * ```
+ * // ✅ Good: calculated during rendering
+ * const fullName = firstName + ' ' + lastName;
+ * ```
+ */
+export function validateNoDerivedComputationsInEffects_exp(
+  fn: HIRFunction,
+): void {
+  const functions: Map<IdentifierId, FunctionExpression> = new Map();
+  const derivationCache = new DerivationCache();
+  const errors = new CompilerError();
+  const effects: Set<HIRFunction> = new Set();
+
+  const setStateCache: Map<string | undefined | null, Array<Place>> = new Map();
+  const effectSetStateCache: Map<
+    string | undefined | null,
+    Array<Place>
+  > = new Map();
+
+  const context: ValidationContext = {
+    functions,
+    errors,
+    derivationCache,
+    effects,
+    setStateCache,
+    effectSetStateCache,
+  };
+
+  if (fn.fnType === 'Hook') {
+    for (const param of fn.params) {
+      if (param.kind === 'Identifier') {
+        context.derivationCache.cache.set(param.identifier.id, {
+          place: param,
+          sourcesIds: new Set([param.identifier.id]),
+          typeOfValue: 'fromProps',
+        });
+        context.derivationCache.hasChanges = true;
+      }
+    }
+  } else if (fn.fnType === 'Component') {
+    const props = fn.params[0];
+    if (props != null && props.kind === 'Identifier') {
+      context.derivationCache.cache.set(props.identifier.id, {
+        place: props,
+        sourcesIds: new Set([props.identifier.id]),
+        typeOfValue: 'fromProps',
+      });
+      context.derivationCache.hasChanges = true;
+    }
+  }
+
+  let isFirstPass = true;
+  do {
+    for (const block of fn.body.blocks.values()) {
+      recordPhiDerivations(block, context);
+      for (const instr of block.instructions) {
+        recordInstructionDerivations(instr, context, isFirstPass);
+      }
+    }
+
+    isFirstPass = false;
+  } while (context.derivationCache.snapshot());
+
+  for (const effect of effects) {
+    validateEffect(effect, context);
+  }
+
+  if (errors.hasAnyErrors()) {
+    throw errors;
+  }
+}
+
+function recordPhiDerivations(
+  block: BasicBlock,
+  context: ValidationContext,
+): void {
+  for (const phi of block.phis) {
+    let typeOfValue: TypeOfValue = 'ignored';
+    let sourcesIds: Set<IdentifierId> = new Set();
+    for (const operand of phi.operands.values()) {
+      const operandMetadata = context.derivationCache.cache.get(
+        operand.identifier.id,
+      );
+
+      if (operandMetadata === undefined) {
+        continue;
+      }
+
+      typeOfValue = joinValue(typeOfValue, operandMetadata.typeOfValue);
+      sourcesIds.add(operand.identifier.id);
+    }
+
+    if (typeOfValue !== 'ignored') {
+      context.derivationCache.addDerivationEntry(
+        phi.place,
+        sourcesIds,
+        typeOfValue,
+      );
+    }
+  }
+}
+
+function joinValue(
+  lvalueType: TypeOfValue,
+  valueType: TypeOfValue,
+): TypeOfValue {
+  if (lvalueType === 'ignored') return valueType;
+  if (valueType === 'ignored') return lvalueType;
+  if (lvalueType === valueType) return lvalueType;
+  return 'fromPropsAndState';
+}
+
+function recordInstructionDerivations(
+  instr: Instruction,
+  context: ValidationContext,
+  isFirstPass: boolean,
+): void {
+  let typeOfValue: TypeOfValue = 'ignored';
+  const sources: Set<IdentifierId> = new Set();
+  const {lvalue, value} = instr;
+  if (value.kind === 'FunctionExpression') {
+    context.functions.set(lvalue.identifier.id, value);
+    for (const [, block] of value.loweredFunc.func.body.blocks) {
+      for (const instr of block.instructions) {
+        recordInstructionDerivations(instr, context, isFirstPass);
+      }
+    }
+  } else if (value.kind === 'CallExpression' || value.kind === 'MethodCall') {
+    const callee =
+      value.kind === 'CallExpression' ? value.callee : value.property;
+    if (
+      isUseEffectHookType(callee.identifier) &&
+      value.args.length === 2 &&
+      value.args[0].kind === 'Identifier' &&
+      value.args[1].kind === 'Identifier'
+    ) {
+      const effectFunction = context.functions.get(value.args[0].identifier.id);
+      if (effectFunction != null) {
+        context.effects.add(effectFunction.loweredFunc.func);
+      }
+    } else if (isUseStateType(lvalue.identifier) && value.args.length > 0) {
+      const stateValueSource = value.args[0];
+      if (stateValueSource.kind === 'Identifier') {
+        sources.add(stateValueSource.identifier.id);
+      }
+      typeOfValue = joinValue(typeOfValue, 'fromState');
+    }
+  }
+
+  for (const operand of eachInstructionOperand(instr)) {
+    if (
+      isSetStateType(operand.identifier) &&
+      operand.loc !== GeneratedSource &&
+      isFirstPass
+    ) {
+      if (context.setStateCache.has(operand.loc.identifierName)) {
+        context.setStateCache.get(operand.loc.identifierName)!.push(operand);
+      } else {
+        context.setStateCache.set(operand.loc.identifierName, [operand]);
+      }
+    }
+
+    const operandMetadata = context.derivationCache.cache.get(
+      operand.identifier.id,
+    );
+
+    if (operandMetadata === undefined) {
+      continue;
+    }
+
+    typeOfValue = joinValue(typeOfValue, operandMetadata.typeOfValue);
+    for (const id of operandMetadata.sourcesIds) {
+      sources.add(id);
+    }
+  }
+
+  if (typeOfValue === 'ignored') {
+    return;
+  }
+
+  for (const lvalue of eachInstructionLValue(instr)) {
+    context.derivationCache.addDerivationEntry(lvalue, sources, typeOfValue);
+  }
+
+  for (const operand of eachInstructionOperand(instr)) {
+    switch (operand.effect) {
+      case Effect.Capture:
+      case Effect.Store:
+      case Effect.ConditionallyMutate:
+      case Effect.ConditionallyMutateIterator:
+      case Effect.Mutate: {
+        if (isMutable(instr, operand)) {
+          context.derivationCache.addDerivationEntry(
+            operand,
+            sources,
+            typeOfValue,
+          );
+        }
+        break;
+      }
+      case Effect.Freeze:
+      case Effect.Read: {
+        // no-op
+        break;
+      }
+      case Effect.Unknown: {
+        CompilerError.invariant(false, {
+          reason: 'Unexpected unknown effect',
+          description: null,
+          details: [
+            {
+              kind: 'error',
+              loc: operand.loc,
+              message: 'Unexpected unknown effect',
+            },
+          ],
+        });
+      }
+      default: {
+        assertExhaustive(
+          operand.effect,
+          `Unexpected effect kind \`${operand.effect}\``,
+        );
+      }
+    }
+  }
+}
+
+function validateEffect(
+  effectFunction: HIRFunction,
+  context: ValidationContext,
+): void {
+  const seenBlocks: Set<BlockId> = new Set();
+
+  const effectDerivedSetStateCalls: Array<{
+    value: CallExpression;
+    loc: SourceLocation;
+    sourceIds: Set<IdentifierId>;
+    typeOfValue: TypeOfValue;
+  }> = [];
+
+  const globals: Set<IdentifierId> = new Set();
+  for (const block of effectFunction.body.blocks.values()) {
+    for (const pred of block.preds) {
+      if (!seenBlocks.has(pred)) {
+        // skip if block has a back edge
+        return;
+      }
+    }
+
+    for (const instr of block.instructions) {
+      // Early return if any instruction is deriving a value from a ref
+      if (isUseRefType(instr.lvalue.identifier)) {
+        return;
+      }
+
+      for (const operand of eachInstructionOperand(instr)) {
+        if (
+          isSetStateType(operand.identifier) &&
+          operand.loc !== GeneratedSource
+        ) {
+          if (context.effectSetStateCache.has(operand.loc.identifierName)) {
+            context.effectSetStateCache
+              .get(operand.loc.identifierName)!
+              .push(operand);
+          } else {
+            context.effectSetStateCache.set(operand.loc.identifierName, [
+              operand,
+            ]);
+          }
+        }
+      }
+
+      if (
+        instr.value.kind === 'CallExpression' &&
+        isSetStateType(instr.value.callee.identifier) &&
+        instr.value.args.length === 1 &&
+        instr.value.args[0].kind === 'Identifier'
+      ) {
+        const argMetadata = context.derivationCache.cache.get(
+          instr.value.args[0].identifier.id,
+        );
+
+        if (argMetadata !== undefined) {
+          effectDerivedSetStateCalls.push({
+            value: instr.value,
+            loc: instr.value.callee.loc,
+            sourceIds: argMetadata.sourcesIds,
+            typeOfValue: argMetadata.typeOfValue,
+          });
+        }
+      } else if (instr.value.kind === 'CallExpression') {
+        const calleeMetadata = context.derivationCache.cache.get(
+          instr.value.callee.identifier.id,
+        );
+
+        if (
+          calleeMetadata !== undefined &&
+          (calleeMetadata.typeOfValue === 'fromProps' ||
+            calleeMetadata.typeOfValue === 'fromPropsAndState')
+        ) {
+          // If the callee is a prop we can't confidently say that it should be derived in render
+          return;
+        }
+
+        if (globals.has(instr.value.callee.identifier.id)) {
+          // If the callee is a global we can't confidently say that it should be derived in render
+          return;
+        }
+      } else if (instr.value.kind === 'LoadGlobal') {
+        globals.add(instr.lvalue.identifier.id);
+        for (const operand of eachInstructionOperand(instr)) {
+          globals.add(operand.identifier.id);
+        }
+      }
+    }
+    seenBlocks.add(block.id);
+  }
+
+  for (const derivedSetStateCall of effectDerivedSetStateCalls) {
+    if (
+      derivedSetStateCall.loc !== GeneratedSource &&
+      context.effectSetStateCache.has(derivedSetStateCall.loc.identifierName) &&
+      context.setStateCache.has(derivedSetStateCall.loc.identifierName) &&
+      context.effectSetStateCache.get(derivedSetStateCall.loc.identifierName)!
+        .length ===
+        context.setStateCache.get(derivedSetStateCall.loc.identifierName)!
+          .length -
+          1
+    ) {
+      const derivedDepsStr = Array.from(derivedSetStateCall.sourceIds)
+        .map(sourceId => {
+          const sourceMetadata = context.derivationCache.cache.get(sourceId);
+          return sourceMetadata?.place.identifier.name?.value;
+        })
+        .filter(Boolean)
+        .join(', ');
+
+      let description;
+
+      if (derivedSetStateCall.typeOfValue === 'fromProps') {
+        description = `From props: [${derivedDepsStr}]`;
+      } else if (derivedSetStateCall.typeOfValue === 'fromState') {
+        description = `From local state: [${derivedDepsStr}]`;
+      } else {
+        description = `From props and local state: [${derivedDepsStr}]`;
+      }
+
+      context.errors.pushDiagnostic(
+        CompilerDiagnostic.create({
+          description: `Derived values (${description}) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user`,
+          category: ErrorCategory.EffectDerivationsOfState,
+          reason:
+            'You might not need an effect. Derive values in render, not effects.',
+        }).withDetails({
+          kind: 'error',
+          loc: derivedSetStateCall.value.callee.loc,
+          message: 'This should be computed during render, not in an effect',
+        }),
+      );
+    }
+  }
+}

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

@@ -184,25 +184,28 @@ function validateNoContextVariableAssignment(
   fn: HIRFunction,
   errors: CompilerError,
 ): void {
+  const context = new Set(fn.context.map(place => place.identifier.id));
   for (const block of fn.body.blocks.values()) {
     for (const instr of block.instructions) {
       const value = instr.value;
       switch (value.kind) {
         case 'StoreContext': {
-          errors.pushDiagnostic(
-            CompilerDiagnostic.create({
-              category: ErrorCategory.UseMemo,
-              reason:
-                'useMemo() callbacks may not reassign variables declared outside of the callback',
-              description:
-                'useMemo() callbacks must be pure functions and cannot reassign variables defined outside of the callback function',
-              suggestions: null,
-            }).withDetails({
-              kind: 'error',
-              loc: value.lvalue.place.loc,
-              message: 'Cannot reassign variable',
-            }),
-          );
+          if (context.has(value.lvalue.place.identifier.id)) {
+            errors.pushDiagnostic(
+              CompilerDiagnostic.create({
+                category: ErrorCategory.UseMemo,
+                reason:
+                  'useMemo() callbacks may not reassign variables declared outside of the callback',
+                description:
+                  'useMemo() callbacks must be pure functions and cannot reassign variables defined outside of the callback function',
+                suggestions: null,
+              }).withDetails({
+                kind: 'error',
+                loc: value.lvalue.place.loc,
+                message: 'Cannot reassign variable',
+              }),
+            );
+          }
           break;
         }
       }

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-from-prop-setter-call-outside-effect-no-error.expect.md

@@ -0,0 +1,84 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({initialName}) {
+  const [name, setName] = useState('');
+
+  useEffect(() => {
+    setName(initialName);
+  }, [initialName]);
+
+  return (
+    <div>
+      <input value={name} onChange={e => setName(e.target.value)} />
+    </div>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{initialName: 'John'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(6);
+  const { initialName } = t0;
+  const [name, setName] = useState("");
+  let t1;
+  let t2;
+  if ($[0] !== initialName) {
+    t1 = () => {
+      setName(initialName);
+    };
+    t2 = [initialName];
+    $[0] = initialName;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] === Symbol.for("react.memo_cache_sentinel")) {
+    t3 = (e) => setName(e.target.value);
+    $[3] = t3;
+  } else {
+    t3 = $[3];
+  }
+  let t4;
+  if ($[4] !== name) {
+    t4 = (
+      <div>
+        <input value={name} onChange={t3} />
+      </div>
+    );
+    $[4] = name;
+    $[5] = t4;
+  } else {
+    t4 = $[5];
+  }
+  return t4;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ initialName: "John" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div><input value="John"></div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-from-prop-setter-call-outside-effect-no-error.js

@@ -0,0 +1,21 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({initialName}) {
+  const [name, setName] = useState('');
+
+  useEffect(() => {
+    setName(initialName);
+  }, [initialName]);
+
+  return (
+    <div>
+      <input value={name} onChange={e => setName(e.target.value)} />
+    </div>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{initialName: 'John'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-from-prop-setter-used-outside-effect-no-error.expect.md

@@ -0,0 +1,85 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function MockComponent({onSet}) {
+  return <div onClick={() => onSet('clicked')}>Mock Component</div>;
+}
+
+function Component({propValue}) {
+  const [value, setValue] = useState(null);
+  useEffect(() => {
+    setValue(propValue);
+  }, [propValue]);
+
+  return <MockComponent onSet={setValue} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{propValue: 'test'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { useEffect, useState } from "react";
+
+function MockComponent(t0) {
+  const $ = _c(2);
+  const { onSet } = t0;
+  let t1;
+  if ($[0] !== onSet) {
+    t1 = <div onClick={() => onSet("clicked")}>Mock Component</div>;
+    $[0] = onSet;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  return t1;
+}
+
+function Component(t0) {
+  const $ = _c(4);
+  const { propValue } = t0;
+  const [, setValue] = useState(null);
+  let t1;
+  let t2;
+  if ($[0] !== propValue) {
+    t1 = () => {
+      setValue(propValue);
+    };
+    t2 = [propValue];
+    $[0] = propValue;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] === Symbol.for("react.memo_cache_sentinel")) {
+    t3 = <MockComponent onSet={setValue} />;
+    $[3] = t3;
+  } else {
+    t3 = $[3];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ propValue: "test" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>Mock Component</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-from-prop-setter-used-outside-effect-no-error.js

@@ -0,0 +1,20 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function MockComponent({onSet}) {
+  return <div onClick={() => onSet('clicked')}>Mock Component</div>;
+}
+
+function Component({propValue}) {
+  const [value, setValue] = useState(null);
+  useEffect(() => {
+    setValue(propValue);
+  }, [propValue]);
+
+  return <MockComponent onSet={setValue} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{propValue: 'test'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-from-ref-and-state-no-error.expect.md

@@ -0,0 +1,73 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState, useRef} from 'react';
+
+export default function Component({test}) {
+  const [local, setLocal] = useState('');
+
+  const myRef = useRef(null);
+
+  useEffect(() => {
+    setLocal(myRef.current + test);
+  }, [test]);
+
+  return <>{local}</>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{test: 'testString'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { useEffect, useState, useRef } from "react";
+
+export default function Component(t0) {
+  const $ = _c(5);
+  const { test } = t0;
+  const [local, setLocal] = useState("");
+
+  const myRef = useRef(null);
+  let t1;
+  let t2;
+  if ($[0] !== test) {
+    t1 = () => {
+      setLocal(myRef.current + test);
+    };
+    t2 = [test];
+    $[0] = test;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] !== local) {
+    t3 = <>{local}</>;
+    $[3] = local;
+    $[4] = t3;
+  } else {
+    t3 = $[4];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ test: "testString" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) nulltestString

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-from-ref-and-state-no-error.js

@@ -0,0 +1,19 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState, useRef} from 'react';
+
+export default function Component({test}) {
+  const [local, setLocal] = useState('');
+
+  const myRef = useRef(null);
+
+  useEffect(() => {
+    setLocal(myRef.current + test);
+  }, [test]);
+
+  return <>{local}</>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{test: 'testString'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/effect-contains-prop-function-call-no-error.expect.md

@@ -0,0 +1,75 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({propValue, onChange}) {
+  const [value, setValue] = useState(null);
+  useEffect(() => {
+    setValue(propValue);
+    onChange();
+  }, [propValue]);
+
+  return <div>{value}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{propValue: 'test', onChange: () => {}}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(7);
+  const { propValue, onChange } = t0;
+  const [value, setValue] = useState(null);
+  let t1;
+  if ($[0] !== onChange || $[1] !== propValue) {
+    t1 = () => {
+      setValue(propValue);
+      onChange();
+    };
+    $[0] = onChange;
+    $[1] = propValue;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  let t2;
+  if ($[3] !== propValue) {
+    t2 = [propValue];
+    $[3] = propValue;
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[5] !== value) {
+    t3 = <div>{value}</div>;
+    $[5] = value;
+    $[6] = t3;
+  } else {
+    t3 = $[6];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ propValue: "test", onChange: () => {} }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>test</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/effect-contains-prop-function-call-no-error.js

@@ -0,0 +1,17 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({propValue, onChange}) {
+  const [value, setValue] = useState(null);
+  useEffect(() => {
+    setValue(propValue);
+    onChange();
+  }, [propValue]);
+
+  return <div>{value}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{propValue: 'test', onChange: () => {}}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/effect-with-global-function-call-no-error.expect.md

@@ -0,0 +1,70 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({propValue}) {
+  const [value, setValue] = useState(null);
+  useEffect(() => {
+    setValue(propValue);
+    globalCall();
+  }, [propValue]);
+
+  return <div>{value}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{propValue: 'test'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(5);
+  const { propValue } = t0;
+  const [value, setValue] = useState(null);
+  let t1;
+  let t2;
+  if ($[0] !== propValue) {
+    t1 = () => {
+      setValue(propValue);
+      globalCall();
+    };
+    t2 = [propValue];
+    $[0] = propValue;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] !== value) {
+    t3 = <div>{value}</div>;
+    $[3] = value;
+    $[4] = t3;
+  } else {
+    t3 = $[4];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ propValue: "test" }],
+};
+
+```
+      
+### Eval output
+(kind: exception) globalCall is not defined

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/effect-with-global-function-call-no-error.js

@@ -0,0 +1,17 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({propValue}) {
+  const [value, setValue] = useState(null);
+  useEffect(() => {
+    setValue(propValue);
+    globalCall();
+  }, [propValue]);
+
+  return <div>{value}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{propValue: 'test'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-conditionally-in-effect.expect.md

@@ -0,0 +1,49 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({value, enabled}) {
+  const [localValue, setLocalValue] = useState('');
+
+  useEffect(() => {
+    if (enabled) {
+      setLocalValue(value);
+    } else {
+      setLocalValue('disabled');
+    }
+  }, [value, enabled]);
+
+  return <div>{localValue}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 'test', enabled: true}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From props: [value]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.derived-state-conditionally-in-effect.ts:9:6
+   7 |   useEffect(() => {
+   8 |     if (enabled) {
+>  9 |       setLocalValue(value);
+     |       ^^^^^^^^^^^^^ This should be computed during render, not in an effect
+  10 |     } else {
+  11 |       setLocalValue('disabled');
+  12 |     }
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-conditionally-in-effect.js

@@ -0,0 +1,21 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({value, enabled}) {
+  const [localValue, setLocalValue] = useState('');
+
+  useEffect(() => {
+    if (enabled) {
+      setLocalValue(value);
+    } else {
+      setLocalValue('disabled');
+    }
+  }, [value, enabled]);
+
+  return <div>{localValue}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 'test', enabled: true}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-from-default-props.expect.md

@@ -0,0 +1,46 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+export default function Component({input = 'empty'}) {
+  const [currInput, setCurrInput] = useState(input);
+  const localConst = 'local const';
+
+  useEffect(() => {
+    setCurrInput(input + localConst);
+  }, [input, localConst]);
+
+  return <div>{currInput}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{input: 'test'}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From props: [input]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.derived-state-from-default-props.ts:9:4
+   7 |
+   8 |   useEffect(() => {
+>  9 |     setCurrInput(input + localConst);
+     |     ^^^^^^^^^^^^ This should be computed during render, not in an effect
+  10 |   }, [input, localConst]);
+  11 |
+  12 |   return <div>{currInput}</div>;
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-from-default-props.js

@@ -0,0 +1,18 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+export default function Component({input = 'empty'}) {
+  const [currInput, setCurrInput] = useState(input);
+  const localConst = 'local const';
+
+  useEffect(() => {
+    setCurrInput(input + localConst);
+  }, [input, localConst]);
+
+  return <div>{currInput}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{input: 'test'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-from-local-state-in-effect.expect.md

@@ -0,0 +1,43 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+
+import {useEffect, useState} from 'react';
+
+function Component({shouldChange}) {
+  const [count, setCount] = useState(0);
+
+  useEffect(() => {
+    if (shouldChange) {
+      setCount(count + 1);
+    }
+  }, [count]);
+
+  return <div>{count}</div>;
+}
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From local state: [count]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.derived-state-from-local-state-in-effect.ts:10:6
+   8 |   useEffect(() => {
+   9 |     if (shouldChange) {
+> 10 |       setCount(count + 1);
+     |       ^^^^^^^^ This should be computed during render, not in an effect
+  11 |     }
+  12 |   }, [count]);
+  13 |
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-from-local-state-in-effect.js

@@ -0,0 +1,15 @@
+// @validateNoDerivedComputationsInEffects_exp
+
+import {useEffect, useState} from 'react';
+
+function Component({shouldChange}) {
+  const [count, setCount] = useState(0);
+
+  useEffect(() => {
+    if (shouldChange) {
+      setCount(count + 1);
+    }
+  }, [count]);
+
+  return <div>{count}</div>;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-from-prop-local-state-and-component-scope.expect.md

@@ -0,0 +1,53 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({firstName}) {
+  const [lastName, setLastName] = useState('Doe');
+  const [fullName, setFullName] = useState('John');
+
+  const middleName = 'D.';
+
+  useEffect(() => {
+    setFullName(firstName + ' ' + middleName + ' ' + lastName);
+  }, [firstName, middleName, lastName]);
+
+  return (
+    <div>
+      <input value={lastName} onChange={e => setLastName(e.target.value)} />
+      <div>{fullName}</div>
+    </div>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{firstName: 'John'}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From props and local state: [firstName, lastName]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.derived-state-from-prop-local-state-and-component-scope.ts:11:4
+   9 |
+  10 |   useEffect(() => {
+> 11 |     setFullName(firstName + ' ' + middleName + ' ' + lastName);
+     |     ^^^^^^^^^^^ This should be computed during render, not in an effect
+  12 |   }, [firstName, middleName, lastName]);
+  13 |
+  14 |   return (
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-from-prop-local-state-and-component-scope.js

@@ -0,0 +1,25 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({firstName}) {
+  const [lastName, setLastName] = useState('Doe');
+  const [fullName, setFullName] = useState('John');
+
+  const middleName = 'D.';
+
+  useEffect(() => {
+    setFullName(firstName + ' ' + middleName + ' ' + lastName);
+  }, [firstName, middleName, lastName]);
+
+  return (
+    <div>
+      <input value={lastName} onChange={e => setLastName(e.target.value)} />
+      <div>{fullName}</div>
+    </div>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{firstName: 'John'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-from-prop-with-side-effect.expect.md

@@ -0,0 +1,46 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({value}) {
+  const [localValue, setLocalValue] = useState('');
+
+  useEffect(() => {
+    setLocalValue(value);
+    document.title = `Value: ${value}`;
+  }, [value]);
+
+  return <div>{localValue}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 'test'}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From props: [value]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.derived-state-from-prop-with-side-effect.ts:8:4
+   6 |
+   7 |   useEffect(() => {
+>  8 |     setLocalValue(value);
+     |     ^^^^^^^^^^^^^ This should be computed during render, not in an effect
+   9 |     document.title = `Value: ${value}`;
+  10 |   }, [value]);
+  11 |
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.derived-state-from-prop-with-side-effect.js

@@ -0,0 +1,18 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({value}) {
+  const [localValue, setLocalValue] = useState('');
+
+  useEffect(() => {
+    setLocalValue(value);
+    document.title = `Value: ${value}`;
+  }, [value]);
+
+  return <div>{localValue}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 'test'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.effect-contains-local-function-call.expect.md

@@ -0,0 +1,50 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({propValue}) {
+  const [value, setValue] = useState(null);
+
+  function localFunction() {
+    console.log('local function');
+  }
+
+  useEffect(() => {
+    setValue(propValue);
+    localFunction();
+  }, [propValue]);
+
+  return <div>{value}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{propValue: 'test'}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From props: [propValue]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.effect-contains-local-function-call.ts:12:4
+  10 |
+  11 |   useEffect(() => {
+> 12 |     setValue(propValue);
+     |     ^^^^^^^^ This should be computed during render, not in an effect
+  13 |     localFunction();
+  14 |   }, [propValue]);
+  15 |
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.effect-contains-local-function-call.js

@@ -0,0 +1,22 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({propValue}) {
+  const [value, setValue] = useState(null);
+
+  function localFunction() {
+    console.log('local function');
+  }
+
+  useEffect(() => {
+    setValue(propValue);
+    localFunction();
+  }, [propValue]);
+
+  return <div>{value}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{propValue: 'test'}],
+};

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

@@ -0,0 +1,48 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component() {
+  const [firstName, setFirstName] = useState('Taylor');
+  const lastName = 'Swift';
+
+  // 🔴 Avoid: redundant state and unnecessary Effect
+  const [fullName, setFullName] = useState('');
+  useEffect(() => {
+    setFullName(firstName + ' ' + lastName);
+  }, [firstName, lastName]);
+
+  return <div>{fullName}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From local state: [firstName]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.invalid-derived-computation-in-effect.ts:11:4
+   9 |   const [fullName, setFullName] = useState('');
+  10 |   useEffect(() => {
+> 11 |     setFullName(firstName + ' ' + lastName);
+     |     ^^^^^^^^^^^ This should be computed during render, not in an effect
+  12 |   }, [firstName, lastName]);
+  13 |
+  14 |   return <div>{fullName}</div>;
+```
+          
+      

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

@@ -0,0 +1,20 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component() {
+  const [firstName, setFirstName] = useState('Taylor');
+  const lastName = 'Swift';
+
+  // 🔴 Avoid: redundant state and unnecessary Effect
+  const [fullName, setFullName] = useState('');
+  useEffect(() => {
+    setFullName(firstName + ' ' + lastName);
+  }, [firstName, lastName]);
+
+  return <div>{fullName}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.invalid-derived-state-from-computed-props.expect.md

@@ -0,0 +1,46 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+export default function Component(props) {
+  const [displayValue, setDisplayValue] = useState('');
+
+  useEffect(() => {
+    const computed = props.prefix + props.value + props.suffix;
+    setDisplayValue(computed);
+  }, [props.prefix, props.value, props.suffix]);
+
+  return <div>{displayValue}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{prefix: '[', value: 'test', suffix: ']'}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From props: [props]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.invalid-derived-state-from-computed-props.ts:9:4
+   7 |   useEffect(() => {
+   8 |     const computed = props.prefix + props.value + props.suffix;
+>  9 |     setDisplayValue(computed);
+     |     ^^^^^^^^^^^^^^^ This should be computed during render, not in an effect
+  10 |   }, [props.prefix, props.value, props.suffix]);
+  11 |
+  12 |   return <div>{displayValue}</div>;
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.invalid-derived-state-from-computed-props.js

@@ -0,0 +1,18 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+export default function Component(props) {
+  const [displayValue, setDisplayValue] = useState('');
+
+  useEffect(() => {
+    const computed = props.prefix + props.value + props.suffix;
+    setDisplayValue(computed);
+  }, [props.prefix, props.value, props.suffix]);
+
+  return <div>{displayValue}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{prefix: '[', value: 'test', suffix: ']'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.invalid-derived-state-from-destructured-props.expect.md

@@ -0,0 +1,47 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+export default function Component({props}) {
+  const [fullName, setFullName] = useState(
+    props.firstName + ' ' + props.lastName
+  );
+
+  useEffect(() => {
+    setFullName(props.firstName + ' ' + props.lastName);
+  }, [props.firstName, props.lastName]);
+
+  return <div>{fullName}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{props: {firstName: 'John', lastName: 'Doe'}}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: You might not need an effect. Derive values in render, not effects.
+
+Derived values (From props: [props]) should be computed during render, rather than in effects. Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user.
+
+error.invalid-derived-state-from-destructured-props.ts:10:4
+   8 |
+   9 |   useEffect(() => {
+> 10 |     setFullName(props.firstName + ' ' + props.lastName);
+     |     ^^^^^^^^^^^ This should be computed during render, not in an effect
+  11 |   }, [props.firstName, props.lastName]);
+  12 |
+  13 |   return <div>{fullName}</div>;
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/error.invalid-derived-state-from-destructured-props.js

@@ -0,0 +1,19 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+export default function Component({props}) {
+  const [fullName, setFullName] = useState(
+    props.firstName + ' ' + props.lastName
+  );
+
+  useEffect(() => {
+    setFullName(props.firstName + ' ' + props.lastName);
+  }, [props.firstName, props.lastName]);
+
+  return <div>{fullName}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{props: {firstName: 'John', lastName: 'Doe'}}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/ref-conditional-in-effect-no-error.expect.md

@@ -0,0 +1,82 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState, useRef} from 'react';
+
+export default function Component({test}) {
+  const [local, setLocal] = useState(0);
+
+  const myRef = useRef(null);
+
+  useEffect(() => {
+    if (myRef.current) {
+      setLocal(test);
+    } else {
+      setLocal(test + test);
+    }
+  }, [test]);
+
+  return <>{local}</>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{test: 4}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { useEffect, useState, useRef } from "react";
+
+export default function Component(t0) {
+  const $ = _c(5);
+  const { test } = t0;
+  const [local, setLocal] = useState(0);
+
+  const myRef = useRef(null);
+  let t1;
+  let t2;
+  if ($[0] !== test) {
+    t1 = () => {
+      if (myRef.current) {
+        setLocal(test);
+      } else {
+        setLocal(test + test);
+      }
+    };
+
+    t2 = [test];
+    $[0] = test;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] !== local) {
+    t3 = <>{local}</>;
+    $[3] = local;
+    $[4] = t3;
+  } else {
+    t3 = $[4];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ test: 4 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) 8

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/ref-conditional-in-effect-no-error.js

@@ -0,0 +1,23 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState, useRef} from 'react';
+
+export default function Component({test}) {
+  const [local, setLocal] = useState(0);
+
+  const myRef = useRef(null);
+
+  useEffect(() => {
+    if (myRef.current) {
+      setLocal(test);
+    } else {
+      setLocal(test + test);
+    }
+  }, [test]);
+
+  return <>{local}</>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{test: 4}],
+};

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

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

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

@@ -3,6 +3,8 @@
 
 ```javascript
 // @validateNoDerivedComputationsInEffects
+import {useEffect, useState} from 'react';
+
 function BadExample() {
   const [firstName, setFirstName] = useState('Taylor');
   const [lastName, setLastName] = useState('Swift');
@@ -10,7 +12,7 @@ function BadExample() {
   // 🔴 Avoid: redundant state and unnecessary Effect
   const [fullName, setFullName] = useState('');
   useEffect(() => {
-    setFullName(capitalize(firstName + ' ' + lastName));
+    setFullName(firstName + ' ' + lastName);
   }, [firstName, lastName]);
 
   return <div>{fullName}</div>;
@@ -26,14 +28,14 @@ Found 1 error:
 
 Error: Values derived from props and state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)
 
-error.invalid-derived-computation-in-effect.ts:9:4
-   7 |   const [fullName, setFullName] = useState('');
-   8 |   useEffect(() => {
->  9 |     setFullName(capitalize(firstName + ' ' + lastName));
+error.invalid-derived-computation-in-effect.ts:11:4
+   9 |   const [fullName, setFullName] = useState('');
+  10 |   useEffect(() => {
+> 11 |     setFullName(firstName + ' ' + lastName);
      |     ^^^^^^^^^^^ Values derived from props and state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)
-  10 |   }, [firstName, lastName]);
-  11 |
-  12 |   return <div>{fullName}</div>;
+  12 |   }, [firstName, lastName]);
+  13 |
+  14 |   return <div>{fullName}</div>;
 ```
           
       

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

@@ -1,4 +1,6 @@
 // @validateNoDerivedComputationsInEffects
+import {useEffect, useState} from 'react';
+
 function BadExample() {
   const [firstName, setFirstName] = useState('Taylor');
   const [lastName, setLastName] = useState('Swift');
@@ -6,7 +8,7 @@ function BadExample() {
   // 🔴 Avoid: redundant state and unnecessary Effect
   const [fullName, setFullName] = useState('');
   useEffect(() => {
-    setFullName(capitalize(firstName + ' ' + lastName));
+    setFullName(firstName + ' ' + lastName);
   }, [firstName, lastName]);
 
   return <div>{fullName}</div>;

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

@@ -60,29 +60,7 @@ This argument is a function which may reassign or mutate `cache` after render, w
 > 22 |     // The original issue is that `cache` was not memoized together with the returned
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 > 23 |     // function. This was because neither appears to ever be mutated — the function
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 24 |     // is known to mutate `cache` but the function isn't called.
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 25 |     //
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 26 |     // The fix is to detect cases like this — functions that are mutable but not called -
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 27 |     // and ensure that their mutable captures are aliased together into the same scope.
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 28 |     const cache = new WeakMap<TInput, TOutput>();
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 29 |     return input => {
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 30 |       let output = cache.get(input);
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 31 |       if (output == null) {
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 32 |         output = map(input);
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 33 |         cache.set(input, output);
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-> 34 |       }
-     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+     …
 > 35 |       return output;
      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 > 36 |     };

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-object-expression-computed-key-modified-during-after-construction-sequence-expr.expect.md

@@ -1,41 +0,0 @@
-
-## Input
-
-```javascript
-import {identity, mutate, mutateAndReturn} from 'shared-runtime';
-
-function Component(props) {
-  const key = {};
-  const context = {
-    [(mutate(key), key)]: identity([props.value]),
-  };
-  mutate(key);
-  return context;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-};
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Todo: (BuildHIR::lowerExpression) Expected Identifier, got SequenceExpression key in ObjectExpression
-
-error.todo-object-expression-computed-key-modified-during-after-construction-sequence-expr.ts:6:6
-  4 |   const key = {};
-  5 |   const context = {
-> 6 |     [(mutate(key), key)]: identity([props.value]),
-    |       ^^^^^^^^^^^^^^^^ (BuildHIR::lowerExpression) Expected Identifier, got SequenceExpression key in ObjectExpression
-  7 |   };
-  8 |   mutate(key);
-  9 |   return context;
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-object-expression-computed-key-modified-during-after-construction.expect.md

@@ -1,41 +0,0 @@
-
-## Input
-
-```javascript
-import {identity, mutate, mutateAndReturn} from 'shared-runtime';
-
-function Component(props) {
-  const key = {};
-  const context = {
-    [mutateAndReturn(key)]: identity([props.value]),
-  };
-  mutate(key);
-  return context;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-};
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Todo: (BuildHIR::lowerExpression) Expected Identifier, got CallExpression key in ObjectExpression
-
-error.todo-object-expression-computed-key-modified-during-after-construction.ts:6:5
-  4 |   const key = {};
-  5 |   const context = {
-> 6 |     [mutateAndReturn(key)]: identity([props.value]),
-    |      ^^^^^^^^^^^^^^^^^^^^ (BuildHIR::lowerExpression) Expected Identifier, got CallExpression key in ObjectExpression
-  7 |   };
-  8 |   mutate(key);
-  9 |   return context;
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-object-expression-computed-key-mutate-key-while-constructing-object.expect.md

@@ -1,40 +0,0 @@
-
-## Input
-
-```javascript
-import {identity, mutate, mutateAndReturn} from 'shared-runtime';
-
-function Component(props) {
-  const key = {};
-  const context = {
-    [mutateAndReturn(key)]: identity([props.value]),
-  };
-  return context;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-};
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Todo: (BuildHIR::lowerExpression) Expected Identifier, got CallExpression key in ObjectExpression
-
-error.todo-object-expression-computed-key-mutate-key-while-constructing-object.ts:6:5
-  4 |   const key = {};
-  5 |   const context = {
-> 6 |     [mutateAndReturn(key)]: identity([props.value]),
-    |      ^^^^^^^^^^^^^^^^^^^^ (BuildHIR::lowerExpression) Expected Identifier, got CallExpression key in ObjectExpression
-  7 |   };
-  8 |   return context;
-  9 | }
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-object-expression-member-expr-call.expect.md

@@ -1,42 +0,0 @@
-
-## Input
-
-```javascript
-import {identity, mutate, mutateAndReturn} from 'shared-runtime';
-
-function Component(props) {
-  const obj = {mutateAndReturn};
-  const key = {};
-  const context = {
-    [obj.mutateAndReturn(key)]: identity([props.value]),
-  };
-  mutate(key);
-  return context;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-};
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Todo: (BuildHIR::lowerExpression) Expected Identifier, got CallExpression key in ObjectExpression
-
-error.todo-object-expression-member-expr-call.ts:7:5
-   5 |   const key = {};
-   6 |   const context = {
->  7 |     [obj.mutateAndReturn(key)]: identity([props.value]),
-     |      ^^^^^^^^^^^^^^^^^^^^^^^^ (BuildHIR::lowerExpression) Expected Identifier, got CallExpression key in ObjectExpression
-   8 |   };
-   9 |   mutate(key);
-  10 |   return context;
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-preserve-memo-deps-mixed-optional-nonoptional-property-chain.expect.md

@@ -64,20 +64,7 @@ error.todo-preserve-memo-deps-mixed-optional-nonoptional-property-chain.ts:7:25
 >  8 |     return identity({
      | ^^^^^^^^^^^^^^^^^^^^^
 >  9 |       callback: () => {
-     | ^^^^^^^^^^^^^^^^^^^^^
-> 10 |         // This is a bug in our dependency inference: we stop capturing dependencies
-     | ^^^^^^^^^^^^^^^^^^^^^
-> 11 |         // after x.a.b?.c. But what this dependency is telling us is that if `x.a.b`
-     | ^^^^^^^^^^^^^^^^^^^^^
-> 12 |         // was non-nullish, then we can access `.c.d?.e`. Thus we should take the
-     | ^^^^^^^^^^^^^^^^^^^^^
-> 13 |         // full property chain, exactly as-is with optionals/non-optionals, as a
-     | ^^^^^^^^^^^^^^^^^^^^^
-> 14 |         // dependency
-     | ^^^^^^^^^^^^^^^^^^^^^
-> 15 |         return identity(x.a.b?.c.d?.e);
-     | ^^^^^^^^^^^^^^^^^^^^^
-> 16 |       },
+     …
      | ^^^^^^^^^^^^^^^^^^^^^
 > 17 |     });
      | ^^^^^^^^^^^^^^^^^^^^^

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/fbt-param-with-leading-whitespace.expect.md

@@ -44,15 +44,23 @@ import fbt from "fbt";
 import { identity } from "shared-runtime";
 
 function Component(props) {
-  const $ = _c(3);
+  const $ = _c(5);
   let t0;
   if ($[0] !== props.count || $[1] !== props.option) {
+    let t1;
+    if ($[3] !== props.count) {
+      t1 = identity(props.count);
+      $[3] = props.count;
+      $[4] = t1;
+    } else {
+      t1 = $[4];
+    }
     t0 = (
       <span>
         {fbt._(
           { "*": "{count} votes for {option}", _1: "1 vote for {option}" },
           [
-            fbt._plural(identity(props.count), "count"),
+            fbt._plural(t1, "count"),
             fbt._param(
               "option",
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/fbt-param-with-trailing-whitespace.expect.md

@@ -44,15 +44,23 @@ import fbt from "fbt";
 import { identity } from "shared-runtime";
 
 function Component(props) {
-  const $ = _c(3);
+  const $ = _c(5);
   let t0;
   if ($[0] !== props.count || $[1] !== props.option) {
+    let t1;
+    if ($[3] !== props.count) {
+      t1 = identity(props.count);
+      $[3] = props.count;
+      $[4] = t1;
+    } else {
+      t1 = $[4];
+    }
     t0 = (
       <span>
         {fbt._(
           { "*": "{count} votes for {option}", _1: "1 vote for {option}" },
           [
-            fbt._plural(identity(props.count), "count"),
+            fbt._plural(t1, "count"),
             fbt._param(
               "option",
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/fbt-preserve-whitespace-two-subtrees.expect.md

@@ -37,7 +37,7 @@ import { c as _c } from "react/compiler-runtime";
 import fbt from "fbt";
 
 function Foo(t0) {
-  const $ = _c(7);
+  const $ = _c(13);
   const { name1, name2 } = t0;
   let t1;
   if ($[0] !== name1 || $[1] !== name2) {
@@ -50,19 +50,34 @@ function Foo(t0) {
       t2 = $[4];
     }
     let t3;
-    if ($[5] !== name2) {
-      t3 = <b>{name2}</b>;
-      $[5] = name2;
-      $[6] = t3;
+    if ($[5] !== name1 || $[6] !== t2) {
+      t3 = <span key={name1}>{t2}</span>;
+      $[5] = name1;
+      $[6] = t2;
+      $[7] = t3;
     } else {
-      t3 = $[6];
+      t3 = $[7];
+    }
+    let t4;
+    if ($[8] !== name2) {
+      t4 = <b>{name2}</b>;
+      $[8] = name2;
+      $[9] = t4;
+    } else {
+      t4 = $[9];
+    }
+    let t5;
+    if ($[10] !== name2 || $[11] !== t4) {
+      t5 = <span key={name2}>{t4}</span>;
+      $[10] = name2;
+      $[11] = t4;
+      $[12] = t5;
+    } else {
+      t5 = $[12];
     }
     t1 = fbt._(
       "{user1} and {user2} accepted your PR!",
-      [
-        fbt._param("user1", <span key={name1}>{t2}</span>),
-        fbt._param("user2", <span key={name2}>{t3}</span>),
-      ],
+      [fbt._param("user1", t3), fbt._param("user2", t5)],
       { hk: "2PxMie" },
     );
     $[0] = name1;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/fbtparam-with-jsx-element-content.expect.md

@@ -29,20 +29,24 @@ import { c as _c } from "react/compiler-runtime";
 import fbt from "fbt";
 
 function Component(t0) {
-  const $ = _c(4);
+  const $ = _c(6);
   const { name, data, icon } = t0;
   let t1;
   if ($[0] !== data || $[1] !== icon || $[2] !== name) {
+    let t2;
+    if ($[4] !== name) {
+      t2 = <Text type="h4">{name}</Text>;
+      $[4] = name;
+      $[5] = t2;
+    } else {
+      t2 = $[5];
+    }
     t1 = (
       <Text type="body4">
         {fbt._(
           "{item author}{icon}{=m2}",
           [
-            fbt._param(
-              "item author",
-
-              <Text type="h4">{name}</Text>,
-            ),
+            fbt._param("item author", t2),
             fbt._param(
               "icon",
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/fbtparam-with-jsx-fragment-value.expect.md

@@ -27,16 +27,21 @@ import fbt from "fbt";
 import { identity } from "shared-runtime";
 
 function Component(props) {
-  const $ = _c(2);
+  const $ = _c(4);
   let t0;
   if ($[0] !== props.text) {
+    const t1 = identity(props.text);
+    let t2;
+    if ($[2] !== t1) {
+      t2 = <>{t1}</>;
+      $[2] = t1;
+      $[3] = t2;
+    } else {
+      t2 = $[3];
+    }
     t0 = (
       <Foo
-        value={fbt._(
-          "{value}%",
-          [fbt._param("value", <>{identity(props.text)}</>)],
-          { hk: "10F5Cc" },
-        )}
+        value={fbt._("{value}%", [fbt._param("value", t2)], { hk: "10F5Cc" })}
       />
     );
     $[0] = props.text;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/recursively-merge-scopes-jsx.expect.md

@@ -0,0 +1,109 @@
+
+## Input
+
+```javascript
+// @flow
+import {fbt} from 'fbt';
+
+function Example({x}) {
+  // "Inner Text" needs to be visible to fbt: the <Bar> element cannot
+  // be memoized separately
+  return (
+    <fbt desc="Description">
+      Outer Text
+      <Foo key="b" x={x}>
+        <Bar key="a">Inner Text</Bar>
+      </Foo>
+    </fbt>
+  );
+}
+
+function Foo({x, children}) {
+  'use no memo';
+  return (
+    <>
+      <div>{x}</div>
+      <span>{children}</span>
+    </>
+  );
+}
+
+function Bar({children}) {
+  'use no memo';
+  return children;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{x: 'Hello'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { fbt } from "fbt";
+
+function Example(t0) {
+  const $ = _c(2);
+  const { x } = t0;
+  let t1;
+  if ($[0] !== x) {
+    t1 = fbt._(
+      "Outer Text {=m1}",
+      [
+        fbt._implicitParam(
+          "=m1",
+
+          <Foo key="b" x={x}>
+            {fbt._(
+              "{=m1}",
+              [
+                fbt._implicitParam(
+                  "=m1",
+                  <Bar key="a">
+                    {fbt._("Inner Text", null, { hk: "32YB0l" })}
+                  </Bar>,
+                ),
+              ],
+              { hk: "23dJsI" },
+            )}
+          </Foo>,
+        ),
+      ],
+      { hk: "2RVA7V" },
+    );
+    $[0] = x;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  return t1;
+}
+
+function Foo({ x, children }) {
+  "use no memo";
+  return (
+    <>
+      <div>{x}</div>
+      <span>{children}</span>
+    </>
+  );
+}
+
+function Bar({ children }) {
+  "use no memo";
+  return children;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{ x: "Hello" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) Outer Text <div>Hello</div><span>Inner Text</span>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/recursively-merge-scopes-jsx.js

@@ -0,0 +1,35 @@
+// @flow
+import {fbt} from 'fbt';
+
+function Example({x}) {
+  // "Inner Text" needs to be visible to fbt: the <Bar> element cannot
+  // be memoized separately
+  return (
+    <fbt desc="Description">
+      Outer Text
+      <Foo key="b" x={x}>
+        <Bar key="a">Inner Text</Bar>
+      </Foo>
+    </fbt>
+  );
+}
+
+function Foo({x, children}) {
+  'use no memo';
+  return (
+    <>
+      <div>{x}</div>
+      <span>{children}</span>
+    </>
+  );
+}
+
+function Bar({children}) {
+  'use no memo';
+  return children;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{x: 'Hello'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/repro-fbt-param-nested-fbt-jsx.expect.md

@@ -0,0 +1,128 @@
+
+## Input
+
+```javascript
+import fbt from 'fbt';
+import {Stringify, identity} from 'shared-runtime';
+
+/**
+ * MemoizeFbtAndMacroOperands needs to account for nested fbt calls.
+ * Expected fixture `fbt-param-call-arguments` to succeed but it failed with error:
+ *   /fbt-param-call-arguments.ts: Line 19 Column 11: fbt: unsupported babel node: Identifier
+ *   ---
+ *   t3
+ *   ---
+ */
+function Component({firstname, lastname}) {
+  'use memo';
+  return (
+    <div>
+      {fbt(
+        [
+          'Name: ',
+          fbt.param('firstname', <Stringify key={0} name={firstname} />),
+          ', ',
+          fbt.param(
+            'lastname',
+            identity(
+              fbt(
+                '(inner)' +
+                  fbt.param('lastname', <Stringify key={1} name={lastname} />),
+                'Inner fbt value'
+              )
+            )
+          ),
+        ],
+        'Name'
+      )}
+    </div>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{firstname: 'first', lastname: 'last'}],
+  sequentialRenders: [{firstname: 'first', lastname: 'last'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import fbt from "fbt";
+import { Stringify, identity } from "shared-runtime";
+
+/**
+ * MemoizeFbtAndMacroOperands needs to account for nested fbt calls.
+ * Expected fixture `fbt-param-call-arguments` to succeed but it failed with error:
+ *   /fbt-param-call-arguments.ts: Line 19 Column 11: fbt: unsupported babel node: Identifier
+ *   ---
+ *   t3
+ *   ---
+ */
+function Component(t0) {
+  "use memo";
+  const $ = _c(9);
+  const { firstname, lastname } = t0;
+  let t1;
+  if ($[0] !== firstname || $[1] !== lastname) {
+    let t2;
+    if ($[3] !== firstname) {
+      t2 = <Stringify key={0} name={firstname} />;
+      $[3] = firstname;
+      $[4] = t2;
+    } else {
+      t2 = $[4];
+    }
+    let t3;
+    if ($[5] !== lastname) {
+      t3 = <Stringify key={1} name={lastname} />;
+      $[5] = lastname;
+      $[6] = t3;
+    } else {
+      t3 = $[6];
+    }
+    t1 = fbt._(
+      "Name: {firstname}, {lastname}",
+      [
+        fbt._param("firstname", t2),
+        fbt._param(
+          "lastname",
+          identity(
+            fbt._("(inner){lastname}", [fbt._param("lastname", t3)], {
+              hk: "1Kdxyo",
+            }),
+          ),
+        ),
+      ],
+      { hk: "3AiIf8" },
+    );
+    $[0] = firstname;
+    $[1] = lastname;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  let t2;
+  if ($[7] !== t1) {
+    t2 = <div>{t1}</div>;
+    $[7] = t1;
+    $[8] = t2;
+  } else {
+    t2 = $[8];
+  }
+  return t2;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ firstname: "first", lastname: "last" }],
+  sequentialRenders: [{ firstname: "first", lastname: "last" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>Name: <div>{"name":"first"}</div>, (inner)<div>{"name":"last"}</div></div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/repro-fbt-param-nested-fbt-jsx.js

@@ -0,0 +1,42 @@
+import fbt from 'fbt';
+import {Stringify, identity} from 'shared-runtime';
+
+/**
+ * MemoizeFbtAndMacroOperands needs to account for nested fbt calls.
+ * Expected fixture `fbt-param-call-arguments` to succeed but it failed with error:
+ *   /fbt-param-call-arguments.ts: Line 19 Column 11: fbt: unsupported babel node: Identifier
+ *   ---
+ *   t3
+ *   ---
+ */
+function Component({firstname, lastname}) {
+  'use memo';
+  return (
+    <div>
+      {fbt(
+        [
+          'Name: ',
+          fbt.param('firstname', <Stringify key={0} name={firstname} />),
+          ', ',
+          fbt.param(
+            'lastname',
+            identity(
+              fbt(
+                '(inner)' +
+                  fbt.param('lastname', <Stringify key={1} name={lastname} />),
+                'Inner fbt value'
+              )
+            )
+          ),
+        ],
+        'Name'
+      )}
+    </div>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{firstname: 'first', lastname: 'last'}],
+  sequentialRenders: [{firstname: 'first', lastname: 'last'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/repro-fbt-param-nested-fbt.expect.md

@@ -3,7 +3,7 @@
 
 ```javascript
 import fbt from 'fbt';
-import {Stringify} from 'shared-runtime';
+import {identity} from 'shared-runtime';
 
 /**
  * MemoizeFbtAndMacroOperands needs to account for nested fbt calls.
@@ -16,22 +16,25 @@ import {Stringify} from 'shared-runtime';
 function Component({firstname, lastname}) {
   'use memo';
   return (
-    <Stringify>
+    <div>
       {fbt(
         [
           'Name: ',
-          fbt.param('firstname', <Stringify key={0} name={firstname} />),
+          fbt.param('firstname', identity(firstname)),
           ', ',
           fbt.param(
             'lastname',
-            <Stringify key={0} name={lastname}>
-              {fbt('(inner fbt)', 'Inner fbt value')}
-            </Stringify>
+            identity(
+              fbt(
+                '(inner)' + fbt.param('lastname', identity(lastname)),
+                'Inner fbt value'
+              )
+            )
           ),
         ],
         'Name'
       )}
-    </Stringify>
+    </div>
   );
 }
 
@@ -48,7 +51,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```javascript
 import { c as _c } from "react/compiler-runtime";
 import fbt from "fbt";
-import { Stringify } from "shared-runtime";
+import { identity } from "shared-runtime";
 
 /**
  * MemoizeFbtAndMacroOperands needs to account for nested fbt calls.
@@ -70,14 +73,24 @@ function Component(t0) {
         fbt._param(
           "firstname",
 
-          <Stringify key={0} name={firstname} />,
+          identity(firstname),
         ),
         fbt._param(
           "lastname",
 
-          <Stringify key={0} name={lastname}>
-            {fbt._("(inner fbt)", null, { hk: "36qNwF" })}
-          </Stringify>,
+          identity(
+            fbt._(
+              "(inner){lastname}",
+              [
+                fbt._param(
+                  "lastname",
+
+                  identity(lastname),
+                ),
+              ],
+              { hk: "1Kdxyo" },
+            ),
+          ),
         ),
       ],
       { hk: "3AiIf8" },
@@ -90,7 +103,7 @@ function Component(t0) {
   }
   let t2;
   if ($[3] !== t1) {
-    t2 = <Stringify>{t1}</Stringify>;
+    t2 = <div>{t1}</div>;
     $[3] = t1;
     $[4] = t2;
   } else {
@@ -108,4 +121,4 @@ export const FIXTURE_ENTRYPOINT = {
 ```
       
 ### Eval output
-(kind: ok) <div>{"children":"Name: , "}</div>
+(kind: ok) <div>Name: first, (inner)last</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/fbt/repro-fbt-param-nested-fbt.js

@@ -1,5 +1,5 @@
 import fbt from 'fbt';
-import {Stringify} from 'shared-runtime';
+import {identity} from 'shared-runtime';
 
 /**
  * MemoizeFbtAndMacroOperands needs to account for nested fbt calls.
@@ -12,22 +12,25 @@ import {Stringify} from 'shared-runtime';
 function Component({firstname, lastname}) {
   'use memo';
   return (
-    <Stringify>
+    <div>
       {fbt(
         [
           'Name: ',
-          fbt.param('firstname', <Stringify key={0} name={firstname} />),
+          fbt.param('firstname', identity(firstname)),
           ', ',
           fbt.param(
             'lastname',
-            <Stringify key={0} name={lastname}>
-              {fbt('(inner fbt)', 'Inner fbt value')}
-            </Stringify>
+            identity(
+              fbt(
+                '(inner)' + fbt.param('lastname', identity(lastname)),
+                'Inner fbt value'
+              )
+            )
           ),
         ],
         'Name'
       )}
-    </Stringify>
+    </div>
   );
 }
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/idx-method-no-outlining-wildcard.expect.md

@@ -37,7 +37,7 @@ function Component(props) {
   const $ = _c(16);
   let t0;
   if ($[0] !== props) {
-    t0 = idx(props, _temp);
+    t0 = idx(props, (_) => _.group.label);
     $[0] = props;
     $[1] = t0;
   } else {
@@ -46,7 +46,7 @@ function Component(props) {
   const groupName1 = t0;
   let t1;
   if ($[2] !== props) {
-    t1 = idx.a(props, _temp2);
+    t1 = idx.a(props, (__0) => __0.group.label);
     $[2] = props;
     $[3] = t1;
   } else {
@@ -108,12 +108,6 @@ function Component(props) {
   }
   return t5;
 }
-function _temp2(__0) {
-  return __0.group.label;
-}
-function _temp(_) {
-  return _.group.label;
-}
 
 ```
       

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/idx-method-no-outlining.expect.md

@@ -31,7 +31,7 @@ function Component(props) {
   const $ = _c(10);
   let t0;
   if ($[0] !== props) {
-    t0 = idx(props, _temp);
+    t0 = idx(props, (_) => _.group.label);
     $[0] = props;
     $[1] = t0;
   } else {
@@ -74,9 +74,6 @@ function Component(props) {
   }
   return t3;
 }
-function _temp(_) {
-  return _.group.label;
-}
 
 ```
       

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/infer-effect-dependencies/bailout-retry/error.todo-syntax.expect.md

@@ -46,18 +46,7 @@ error.todo-syntax.ts:11:2
 > 12 |     () => {
      | ^^^^^^^^^^^
 > 13 |       try {
-     | ^^^^^^^^^^^
-> 14 |         console.log(prop1);
-     | ^^^^^^^^^^^
-> 15 |       } finally {
-     | ^^^^^^^^^^^
-> 16 |         console.log('exiting');
-     | ^^^^^^^^^^^
-> 17 |       }
-     | ^^^^^^^^^^^
-> 18 |     },
-     | ^^^^^^^^^^^
-> 19 |     [prop1],
+     …
      | ^^^^^^^^^^^
 > 20 |     AUTODEPS
      | ^^^^^^^^^^^

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/nonmutated-spread-hook-return.expect.md

@@ -0,0 +1,63 @@
+
+## Input
+
+```javascript
+import {identity, Stringify, useIdentity} from 'shared-runtime';
+
+function Component(props) {
+  const {x, ...rest} = useIdentity(props);
+  const z = rest.z;
+  identity(z);
+  return <Stringify x={x} z={z} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 'Hello', z: 'World'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, Stringify, useIdentity } from "shared-runtime";
+
+function Component(props) {
+  const $ = _c(6);
+  const t0 = useIdentity(props);
+  let rest;
+  let x;
+  if ($[0] !== t0) {
+    ({ x, ...rest } = t0);
+    $[0] = t0;
+    $[1] = rest;
+    $[2] = x;
+  } else {
+    rest = $[1];
+    x = $[2];
+  }
+  const z = rest.z;
+  identity(z);
+  let t1;
+  if ($[3] !== x || $[4] !== z) {
+    t1 = <Stringify x={x} z={z} />;
+    $[3] = x;
+    $[4] = z;
+    $[5] = t1;
+  } else {
+    t1 = $[5];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ x: "Hello", z: "World" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"x":"Hello","z":"World"}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/nonmutated-spread-hook-return.js

@@ -0,0 +1,13 @@
+import {identity, Stringify, useIdentity} from 'shared-runtime';
+
+function Component(props) {
+  const {x, ...rest} = useIdentity(props);
+  const z = rest.z;
+  identity(z);
+  return <Stringify x={x} z={z} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 'Hello', z: 'World'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/nonmutated-spread-props-jsx.expect.md

@@ -0,0 +1,57 @@
+
+## Input
+
+```javascript
+import {identity, Stringify} from 'shared-runtime';
+
+function Component({x, ...rest}) {
+  return <Stringify {...rest} x={x} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 'Hello', z: 'World'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, Stringify } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(6);
+  let rest;
+  let x;
+  if ($[0] !== t0) {
+    ({ x, ...rest } = t0);
+    $[0] = t0;
+    $[1] = rest;
+    $[2] = x;
+  } else {
+    rest = $[1];
+    x = $[2];
+  }
+  let t1;
+  if ($[3] !== rest || $[4] !== x) {
+    t1 = <Stringify {...rest} x={x} />;
+    $[3] = rest;
+    $[4] = x;
+    $[5] = t1;
+  } else {
+    t1 = $[5];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ x: "Hello", z: "World" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"z":"World","x":"Hello"}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/nonmutated-spread-props-jsx.js

@@ -0,0 +1,10 @@
+import {identity, Stringify} from 'shared-runtime';
+
+function Component({x, ...rest}) {
+  return <Stringify {...rest} x={x} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 'Hello', z: 'World'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/nonmutated-spread-props-local-indirection.expect.md

@@ -0,0 +1,63 @@
+
+## Input
+
+```javascript
+import {identity, Stringify} from 'shared-runtime';
+
+function Component({x, ...rest}) {
+  const restAlias = rest;
+  const z = restAlias.z;
+  identity(z);
+  return <Stringify x={x} z={z} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 'Hello', z: 'World'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, Stringify } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(6);
+  let rest;
+  let x;
+  if ($[0] !== t0) {
+    ({ x, ...rest } = t0);
+    $[0] = t0;
+    $[1] = rest;
+    $[2] = x;
+  } else {
+    rest = $[1];
+    x = $[2];
+  }
+  const restAlias = rest;
+  const z = restAlias.z;
+  identity(z);
+  let t1;
+  if ($[3] !== x || $[4] !== z) {
+    t1 = <Stringify x={x} z={z} />;
+    $[3] = x;
+    $[4] = z;
+    $[5] = t1;
+  } else {
+    t1 = $[5];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ x: "Hello", z: "World" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"x":"Hello","z":"World"}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/nonmutated-spread-props-local-indirection.js

@@ -0,0 +1,13 @@
+import {identity, Stringify} from 'shared-runtime';
+
+function Component({x, ...rest}) {
+  const restAlias = rest;
+  const z = restAlias.z;
+  identity(z);
+  return <Stringify x={x} z={z} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 'Hello', z: 'World'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/nonmutated-spread-props.expect.md

@@ -0,0 +1,61 @@
+
+## Input
+
+```javascript
+import {identity, Stringify} from 'shared-runtime';
+
+function Component({x, ...rest}) {
+  const z = rest.z;
+  identity(z);
+  return <Stringify x={x} z={z} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 'Hello', z: 'World'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, Stringify } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(6);
+  let rest;
+  let x;
+  if ($[0] !== t0) {
+    ({ x, ...rest } = t0);
+    $[0] = t0;
+    $[1] = rest;
+    $[2] = x;
+  } else {
+    rest = $[1];
+    x = $[2];
+  }
+  const z = rest.z;
+  identity(z);
+  let t1;
+  if ($[3] !== x || $[4] !== z) {
+    t1 = <Stringify x={x} z={z} />;
+    $[3] = x;
+    $[4] = z;
+    $[5] = t1;
+  } else {
+    t1 = $[5];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ x: "Hello", z: "World" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"x":"Hello","z":"World"}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/nonmutated-spread-props.js

@@ -0,0 +1,12 @@
+import {identity, Stringify} from 'shared-runtime';
+
+function Component({x, ...rest}) {
+  const z = rest.z;
+  identity(z);
+  return <Stringify x={x} z={z} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 'Hello', z: 'World'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/object-expression-computed-key-modified-during-after-construction-sequence-expr.expect.md

@@ -0,0 +1,56 @@
+
+## Input
+
+```javascript
+import {identity, mutate, mutateAndReturn} from 'shared-runtime';
+
+function Component(props) {
+  const key = {};
+  const context = {
+    [(mutate(key), key)]: identity([props.value]),
+  };
+  mutate(key);
+  return [context, key];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 42}],
+  sequentialRenders: [{value: 42}, {value: 42}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, mutate, mutateAndReturn } from "shared-runtime";
+
+function Component(props) {
+  const $ = _c(2);
+  let t0;
+  if ($[0] !== props.value) {
+    const key = {};
+    const context = { [(mutate(key), key)]: identity([props.value]) };
+    mutate(key);
+    t0 = [context, key];
+    $[0] = props.value;
+    $[1] = t0;
+  } else {
+    t0 = $[1];
+  }
+  return t0;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ value: 42 }],
+  sequentialRenders: [{ value: 42 }, { value: 42 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+[{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/object-expression-computed-key-modified-during-after-construction-sequence-expr.js

@@ -6,10 +6,11 @@ function Component(props) {
     [(mutate(key), key)]: identity([props.value]),
   };
   mutate(key);
-  return context;
+  return [context, key];
 }
 
 export const FIXTURE_ENTRYPOINT = {
   fn: Component,
   params: [{value: 42}],
+  sequentialRenders: [{value: 42}, {value: 42}],
 };

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/object-expression-computed-key-modified-during-after-construction.expect.md

@@ -0,0 +1,55 @@
+
+## Input
+
+```javascript
+import {identity, mutate, mutateAndReturn} from 'shared-runtime';
+
+function Component(props) {
+  const key = {};
+  const context = {
+    [mutateAndReturn(key)]: identity([props.value]),
+  };
+  mutate(key);
+  return context;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 42}],
+  sequentialRenders: [{value: 42}, {value: 42}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, mutate, mutateAndReturn } from "shared-runtime";
+
+function Component(props) {
+  const $ = _c(2);
+  let context;
+  if ($[0] !== props.value) {
+    const key = {};
+    context = { [mutateAndReturn(key)]: identity([props.value]) };
+    mutate(key);
+    $[0] = props.value;
+    $[1] = context;
+  } else {
+    context = $[1];
+  }
+  return context;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ value: 42 }],
+  sequentialRenders: [{ value: 42 }, { value: 42 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) {"[object Object]":[42]}
+{"[object Object]":[42]}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/object-expression-computed-key-modified-during-after-construction.js

@@ -12,4 +12,5 @@ function Component(props) {
 export const FIXTURE_ENTRYPOINT = {
   fn: Component,
   params: [{value: 42}],
+  sequentialRenders: [{value: 42}, {value: 42}],
 };

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/object-expression-computed-key-mutate-key-while-constructing-object.expect.md

@@ -0,0 +1,67 @@
+
+## Input
+
+```javascript
+import {identity, mutate, mutateAndReturn} from 'shared-runtime';
+
+function Component(props) {
+  const key = {};
+  const context = {
+    [mutateAndReturn(key)]: identity([props.value]),
+  };
+  return context;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 42}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, mutate, mutateAndReturn } from "shared-runtime";
+
+function Component(props) {
+  const $ = _c(5);
+  let t0;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    const key = {};
+
+    t0 = mutateAndReturn(key);
+    $[0] = t0;
+  } else {
+    t0 = $[0];
+  }
+  let t1;
+  if ($[1] !== props.value) {
+    t1 = identity([props.value]);
+    $[1] = props.value;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  let t2;
+  if ($[3] !== t1) {
+    t2 = { [t0]: t1 };
+    $[3] = t1;
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  const context = t2;
+  return context;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ value: 42 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) {"[object Object]":[42]}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/object-expression-member-expr-call.expect.md

@@ -0,0 +1,54 @@
+
+## Input
+
+```javascript
+import {identity, mutate, mutateAndReturn} from 'shared-runtime';
+
+function Component(props) {
+  const obj = {mutateAndReturn};
+  const key = {};
+  const context = {
+    [obj.mutateAndReturn(key)]: identity([props.value]),
+  };
+  mutate(key);
+  return context;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 42}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, mutate, mutateAndReturn } from "shared-runtime";
+
+function Component(props) {
+  const $ = _c(2);
+  let context;
+  if ($[0] !== props.value) {
+    const obj = { mutateAndReturn };
+    const key = {};
+    context = { [obj.mutateAndReturn(key)]: identity([props.value]) };
+    mutate(key);
+    $[0] = props.value;
+    $[1] = context;
+  } else {
+    context = $[1];
+  }
+  return context;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ value: 42 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) {"[object Object]":[42]}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.false-positive-useMemo-dropped-infer-always-invalidating.expect.md

@@ -0,0 +1,49 @@
+
+## Input
+
+```javascript
+// @validatePreserveExistingMemoizationGuarantees
+
+import {useMemo} from 'react';
+import {useHook} from 'shared-runtime';
+
+// useMemo values may not be memoized in Forget output if we
+// infer that their deps always invalidate.
+// This is technically a false positive as the useMemo in source
+// was effectively a no-op
+function useFoo(props) {
+  const x = [];
+  useHook();
+  x.push(props);
+
+  return useMemo(() => [x], [x]);
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Compilation Skipped: Existing memoization could not be preserved
+
+React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
+
+error.false-positive-useMemo-dropped-infer-always-invalidating.ts:15:9
+  13 |   x.push(props);
+  14 |
+> 15 |   return useMemo(() => [x], [x]);
+     |          ^^^^^^^^^^^^^^^^^^^^^^^ Could not preserve existing memoization
+  16 | }
+  17 |
+  18 | export const FIXTURE_ENTRYPOINT = {
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.false-positive-useMemo-dropped-infer-always-invalidating.ts

@@ -0,0 +1,21 @@
+// @validatePreserveExistingMemoizationGuarantees
+
+import {useMemo} from 'react';
+import {useHook} from 'shared-runtime';
+
+// useMemo values may not be memoized in Forget output if we
+// infer that their deps always invalidate.
+// This is technically a false positive as the useMemo in source
+// was effectively a no-op
+function useFoo(props) {
+  const x = [];
+  useHook();
+  x.push(props);
+
+  return useMemo(() => [x], [x]);
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/repro-useMemo-counts-as-preserved-if-it-was-always-invalidating.expect.md

@@ -1,56 +0,0 @@
-
-## Input
-
-```javascript
-// @validatePreserveExistingMemoizationGuarantees
-
-import {useMemo} from 'react';
-import {useHook} from 'shared-runtime';
-
-// If we can prove that a useMemo was ineffective because it would always invalidate,
-// then we shouldn't throw a "couldn't preserve existing memoization" error
-// TODO: consider reporting a separate error to the user for this case, if you're going
-// to memoize manually, then you probably want to know that it's a no-op
-function useFoo(props) {
-  const x = [];
-  useHook();
-  x.push(props);
-
-  return useMemo(() => [x], [x]);
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: useFoo,
-  params: [{}],
-};
-
-```
-
-## Code
-
-```javascript
-// @validatePreserveExistingMemoizationGuarantees
-
-import { useMemo } from "react";
-import { useHook } from "shared-runtime";
-
-// If we can prove that a useMemo was ineffective because it would always invalidate,
-// then we shouldn't throw a "couldn't preserve existing memoization" error
-// TODO: consider reporting a separate error to the user for this case, if you're going
-// to memoize manually, then you probably want to know that it's a no-op
-function useFoo(props) {
-  const x = [];
-  useHook();
-  x.push(props);
-  return [x];
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: useFoo,
-  params: [{}],
-};
-
-```
-      
-### Eval output
-(kind: ok) [[{}]]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/repro-useMemo-counts-as-preserved-if-it-was-always-invalidating.ts

@@ -1,21 +0,0 @@
-// @validatePreserveExistingMemoizationGuarantees
-
-import {useMemo} from 'react';
-import {useHook} from 'shared-runtime';
-
-// If we can prove that a useMemo was ineffective because it would always invalidate,
-// then we shouldn't throw a "couldn't preserve existing memoization" error
-// TODO: consider reporting a separate error to the user for this case, if you're going
-// to memoize manually, then you probably want to know that it's a no-op
-function useFoo(props) {
-  const x = [];
-  useHook();
-  x.push(props);
-
-  return useMemo(() => [x], [x]);
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: useFoo,
-  params: [{}],
-};

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

@@ -0,0 +1,45 @@
+
+## Input
+
+```javascript
+// @flow
+export hook useItemLanguage(items) {
+  return useMemo(() => {
+    let language: ?string = null;
+    items.forEach(item => {
+      if (item.language != null) {
+        language = item.language;
+      }
+    });
+    return language;
+  }, [items]);
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+export function useItemLanguage(items) {
+  const $ = _c(2);
+  let language;
+  if ($[0] !== items) {
+    language = null;
+    items.forEach((item) => {
+      if (item.language != null) {
+        language = item.language;
+      }
+    });
+    $[0] = items;
+    $[1] = language;
+  } else {
+    language = $[1];
+  }
+  return language;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

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

@@ -0,0 +1,12 @@
+// @flow
+export hook useItemLanguage(items) {
+  return useMemo(() => {
+    let language: ?string = null;
+    items.forEach(item => {
+      if (item.language != null) {
+        language = item.language;
+      }
+    });
+    return language;
+  }, [items]);
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-inline-unnamed-useMemo-with-multiple-returns.expect.md

@@ -1,98 +0,0 @@
-
-## Input
-
-```javascript
-import {useMemo} from 'react';
-import {identity, useIdentity} from 'shared-runtime';
-
-// Adapted from https://github.com/facebook/react/issues/34750
-function useLocalCampaignBySlug(slug: string) {
-  const campaigns = useIdentity({a: {slug: 'a', name: 'campaign'}});
-  // The useMemo result is never assigned to a local so we did not previously ensure
-  // that there was a variable declaration for it when promoting the result temporary
-  return useMemo(() => {
-    for (const id of Object.keys(campaigns)) {
-      const campaign = campaigns[id];
-      if (campaign.slug === slug) {
-        return identity(campaign);
-      }
-    }
-    return null;
-  }, [campaigns, slug]);
-}
-
-function Component() {
-  const campaign = useLocalCampaignBySlug('a');
-  return <div>{campaign.name}</div>;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{}],
-};
-
-```
-
-## Code
-
-```javascript
-import { c as _c } from "react/compiler-runtime";
-import { useMemo } from "react";
-import { identity, useIdentity } from "shared-runtime";
-
-// Adapted from https://github.com/facebook/react/issues/34750
-function useLocalCampaignBySlug(slug) {
-  const $ = _c(4);
-  let t0;
-  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = { a: { slug: "a", name: "campaign" } };
-    $[0] = t0;
-  } else {
-    t0 = $[0];
-  }
-  const campaigns = useIdentity(t0);
-  let t1;
-  if ($[1] !== campaigns || $[2] !== slug) {
-    bb0: {
-      for (const id of Object.keys(campaigns)) {
-        const campaign = campaigns[id];
-        if (campaign.slug === slug) {
-          t1 = identity(campaign);
-          break bb0;
-        }
-      }
-
-      t1 = null;
-    }
-    $[1] = campaigns;
-    $[2] = slug;
-    $[3] = t1;
-  } else {
-    t1 = $[3];
-  }
-  return t1;
-}
-
-function Component() {
-  const $ = _c(2);
-  const campaign = useLocalCampaignBySlug("a");
-  let t0;
-  if ($[0] !== campaign.name) {
-    t0 = <div>{campaign.name}</div>;
-    $[0] = campaign.name;
-    $[1] = t0;
-  } else {
-    t0 = $[1];
-  }
-  return t0;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{}],
-};
-
-```
-      
-### Eval output
-(kind: ok) <div>campaign</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-inline-unnamed-useMemo-with-multiple-returns.js

@@ -1,28 +0,0 @@
-import {useMemo} from 'react';
-import {identity, useIdentity} from 'shared-runtime';
-
-// Adapted from https://github.com/facebook/react/issues/34750
-function useLocalCampaignBySlug(slug: string) {
-  const campaigns = useIdentity({a: {slug: 'a', name: 'campaign'}});
-  // The useMemo result is never assigned to a local so we did not previously ensure
-  // that there was a variable declaration for it when promoting the result temporary
-  return useMemo(() => {
-    for (const id of Object.keys(campaigns)) {
-      const campaign = campaigns[id];
-      if (campaign.slug === slug) {
-        return identity(campaign);
-      }
-    }
-    return null;
-  }, [campaigns, slug]);
-}
-
-function Component() {
-  const campaign = useLocalCampaignBySlug('a');
-  return <div>{campaign.name}</div>;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{}],
-};

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

@@ -29,10 +29,13 @@ export {
   ProgramContext,
   tryFindDirectiveEnablingMemoization as findDirectiveEnablingMemoization,
   findDirectiveDisablingMemoization,
+  defaultOptions,
   type CompilerPipelineValue,
   type Logger,
   type LoggerEvent,
   type PluginOptions,
+  type AutoDepsDecorationsEvent,
+  type CompileSuccessEvent,
 } from './Entrypoint';
 export {
   Effect,

compiler/packages/react-forgive/package.json

@@ -36,13 +36,14 @@
   },
   "scripts": {
     "build": "yarn run compile",
+    "build:compiler": "yarn workspace babel-plugin-react-compiler build --dts",
     "compile": "rimraf dist && concurrently -n server,client \"scripts/build.mjs -t server\" \"scripts/build.mjs -t client\"",
     "dev": "yarn run package && yarn run install-ext",
     "install-ext": "code --install-extension react-forgive-0.0.0.vsix",
     "lint": "echo 'no tests'",
     "package": "rm -f react-forgive-0.0.0.vsix && vsce package --yarn",
     "postinstall": "cd client && yarn install && cd ../server && yarn install && cd ..",
-    "pretest": "yarn run compile && yarn run lint",
+    "pretest": "yarn run build:compiler && yarn run compile && yarn run lint",
     "test": "vscode-test",
     "vscode:prepublish": "yarn run compile",
     "watch": "scripts/build.mjs --watch"

compiler/packages/react-forgive/server/package.json

@@ -18,7 +18,6 @@
     "@babel/parser": "^7.26.0",
     "@babel/plugin-syntax-typescript": "^7.25.9",
     "@babel/types": "^7.26.0",
-    "cosmiconfig": "^9.0.0",
     "prettier": "^3.3.3",
     "vscode-languageserver": "^9.0.1",
     "vscode-languageserver-textdocument": "^1.0.12"

compiler/packages/react-forgive/server/src/compiler/compat.ts

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import {SourceLocation} from 'babel-plugin-react-compiler/src';
+import {type SourceLocation} from 'babel-plugin-react-compiler';
 import {type Range} from 'vscode-languageserver';
 
 export function babelLocationToRange(loc: SourceLocation): Range | null {

compiler/packages/react-forgive/server/src/compiler/index.ts

@@ -9,7 +9,7 @@ import type * as BabelCore from '@babel/core';
 import {parseAsync, transformFromAstAsync} from '@babel/core';
 import BabelPluginReactCompiler, {
   type PluginOptions,
-} from 'babel-plugin-react-compiler/src';
+} from 'babel-plugin-react-compiler';
 import * as babelParser from 'prettier/plugins/babel.js';
 import estreeParser from 'prettier/plugins/estree';
 import * as typescriptParser from 'prettier/plugins/typescript';