[compiler] Prevent innaccurate derivation recording on FunctionExpressions on no-derived-computation-in-effects

Summary:
The operands of a function expression are the elements passed as context. This means that it doesn't make sense to record mutations for them.

The relevant mutations will happen in the function body, so we need to prevent FunctionExpression type instruction from running the logic for effect mutations.

This was also causing some values to depend on themselves in some cases triggering an infinite loop. Also added n invariant to prevent this issue

Test Plan:
Added fixture test

.github/ISSUE_TEMPLATE/compiler_bug_report.yml

@@ -11,7 +11,7 @@ body:
     options:
       - label: React Compiler core (the JS output is incorrect, or your app works incorrectly after optimization)
       - label: babel-plugin-react-compiler (build issue installing or using the Babel plugin)
-      - label: eslint-plugin-react-compiler (build issue installing or using the eslint plugin)
+      - label: eslint-plugin-react-hooks (build issue installing or using the eslint plugin)
       - label: react-compiler-healthcheck (build issue installing or using the healthcheck script)
 - type: input
   attributes:

.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

compiler/apps/playground/package.json

@@ -27,7 +27,7 @@
     "@babel/types": "7.26.3",
     "@heroicons/react": "^1.0.6",
     "@monaco-editor/react": "^4.8.0-rc.2",
-    "@playwright/test": "^1.51.1",
+    "@playwright/test": "^1.56.1",
     "@use-gesture/react": "^10.2.22",
     "hermes-eslint": "^0.25.0",
     "hermes-parser": "^0.25.0",

compiler/apps/playground/yarn.lock

@@ -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"
@@ -854,23 +854,11 @@
   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@19.2":
   version "19.2.2"
   resolved "https://registry.npmjs.org/@types/react/-/react-19.2.2.tgz#ba123a75d4c2a51158697160a4ea2ff70aa6bf36"
@@ -3465,17 +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"
 

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

@@ -105,6 +105,7 @@ import {inferMutationAliasingRanges} from '../Inference/InferMutationAliasingRan
 import {validateNoDerivedComputationsInEffects} from '../Validation/ValidateNoDerivedComputationsInEffects';
 import {validateNoDerivedComputationsInEffects_exp} from '../Validation/ValidateNoDerivedComputationsInEffects_exp';
 import {nameAnonymousFunctions} from '../Transform/NameAnonymousFunctions';
+import {validateSourceLocations} from '../Validation/ValidateSourceLocations';
 
 export type CompilerPipelineValue =
   | {kind: 'ast'; name: string; value: CodegenFunction}
@@ -272,12 +273,10 @@ function runWithEnvironment(
       validateNoSetStateInRender(hir).unwrap();
     }
 
-    if (env.config.validateNoDerivedComputationsInEffects) {
-      validateNoDerivedComputationsInEffects(hir);
-    }
-
     if (env.config.validateNoDerivedComputationsInEffects_exp) {
-      validateNoDerivedComputationsInEffects_exp(hir);
+      env.logErrors(validateNoDerivedComputationsInEffects_exp(hir));
+    } else if (env.config.validateNoDerivedComputationsInEffects) {
+      validateNoDerivedComputationsInEffects(hir);
     }
 
     if (env.config.validateNoSetStateInEffects) {
@@ -559,6 +558,10 @@ function runWithEnvironment(
     log({kind: 'ast', name: 'Codegen (outlined)', value: outlined.fn});
   }
 
+  if (env.config.validateSourceLocations) {
+    validateSourceLocations(func, ast).unwrap();
+  }
+
   /**
    * This flag should be only set for unit / fixture tests to check
    * that Forget correctly handles unexpected errors (e.g. exceptions

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

@@ -364,6 +364,13 @@ export const EnvironmentConfigSchema = z.object({
   validateNoCapitalizedCalls: z.nullable(z.array(z.string())).default(null),
   validateBlocklistedImports: z.nullable(z.array(z.string())).default(null),
 
+  /**
+   * Validates that AST nodes generated during codegen have proper source locations.
+   * This is useful for debugging issues with source maps and Istanbul coverage.
+   * When enabled, the compiler will error if important source locations are missing in the generated AST.
+   */
+  validateSourceLocations: z.boolean().default(false),
+
   /**
    * Validate against impure functions called during render
    */
@@ -665,11 +672,25 @@ export const EnvironmentConfigSchema = z.object({
   validateNoDynamicallyCreatedComponentsOrHooks: z.boolean().default(false),
 
   /**
-   * When enabled, allows setState calls in effects when the value being set is
-   * derived from a ref. This is useful for patterns where initial layout measurements
-   * from refs need to be stored in state during mount.
+   * When enabled, allows setState calls in effects based on valid patterns involving refs:
+   * - Allow setState where the value being set is derived from a ref. This is useful where
+   *   state needs to take into account layer information, and a layout effect reads layout
+   *   data from a ref and sets state.
+   * - Allow conditionally calling setState after manually comparing previous/new values
+   *   for changes via a ref. Relying on effect deps is insufficient for non-primitive values,
+   *   so a ref is generally required to manually track previous values and compare prev/next
+   *   for meaningful changes before setting state.
    */
   enableAllowSetStateFromRefsInEffects: z.boolean().default(true),
+
+  /**
+   * Enables inference of event handler types for JSX props on built-in DOM elements.
+   * When enabled, functions passed to event handler props (props starting with "on")
+   * on primitive JSX tags are inferred to have the BuiltinEventHandlerId type, which
+   * allows ref access within those functions since DOM event handlers are guaranteed
+   * by React to only execute in response to events, not during render.
+   */
+  enableInferEventHandlers: z.boolean().default(false),
 });
 
 export type EnvironmentConfig = z.infer<typeof EnvironmentConfigSchema>;

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

@@ -23,13 +23,14 @@ import {
   BuiltInUseInsertionEffectHookId,
   BuiltInUseLayoutEffectHookId,
   BuiltInUseOperatorId,
+  BuiltInUseOptimisticId,
   BuiltInUseReducerId,
   BuiltInUseRefId,
   BuiltInUseStateId,
   BuiltInUseTransitionId,
   BuiltInWeakMapId,
   BuiltInWeakSetId,
-  BuiltinEffectEventId,
+  BuiltInEffectEventId,
   ReanimatedSharedValueId,
   ShapeRegistry,
   addFunction,
@@ -818,6 +819,18 @@ const REACT_APIS: Array<[string, BuiltInType]> = [
       returnValueKind: ValueKind.Frozen,
     }),
   ],
+  [
+    'useOptimistic',
+    addHook(DEFAULT_SHAPES, {
+      positionalParams: [],
+      restParam: Effect.Freeze,
+      returnType: {kind: 'Object', shapeId: BuiltInUseOptimisticId},
+      calleeEffect: Effect.Read,
+      hookKind: 'useOptimistic',
+      returnValueKind: ValueKind.Frozen,
+      returnValueReason: ValueReason.State,
+    }),
+  ],
   [
     'use',
     addFunction(
@@ -863,7 +876,7 @@ const REACT_APIS: Array<[string, BuiltInType]> = [
         returnType: {
           kind: 'Function',
           return: {kind: 'Poly'},
-          shapeId: BuiltinEffectEventId,
+          shapeId: BuiltInEffectEventId,
           isConstructor: false,
         },
         calleeEffect: Effect.Read,

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

@@ -1887,6 +1887,18 @@ export function isStartTransitionType(id: Identifier): boolean {
   );
 }
 
+export function isUseOptimisticType(id: Identifier): boolean {
+  return (
+    id.type.kind === 'Object' && id.type.shapeId === 'BuiltInUseOptimistic'
+  );
+}
+
+export function isSetOptimisticType(id: Identifier): boolean {
+  return (
+    id.type.kind === 'Function' && id.type.shapeId === 'BuiltInSetOptimistic'
+  );
+}
+
 export function isSetActionStateType(id: Identifier): boolean {
   return (
     id.type.kind === 'Function' && id.type.shapeId === 'BuiltInSetActionState'
@@ -1920,7 +1932,8 @@ export function isStableType(id: Identifier): boolean {
     isSetActionStateType(id) ||
     isDispatcherType(id) ||
     isUseRefType(id) ||
-    isStartTransitionType(id)
+    isStartTransitionType(id) ||
+    isSetOptimisticType(id)
   );
 }
 
@@ -1931,8 +1944,9 @@ export function isStableTypeContainer(id: Identifier): boolean {
   }
   return (
     isUseStateType(id) || // setState
-    type_.shapeId === 'BuiltInUseActionState' || // setActionState
+    isUseActionStateType(id) || // setActionState
     isUseReducerType(id) || // dispatcher
+    isUseOptimisticType(id) || // setOptimistic
     type_.shapeId === 'BuiltInUseTransition' // startTransition
   );
 }
@@ -1952,6 +1966,7 @@ export function evaluatesToStableTypeOrContainer(
       case 'useActionState':
       case 'useRef':
       case 'useTransition':
+      case 'useOptimistic':
         return true;
     }
   }

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

@@ -304,6 +304,7 @@ export type HookKind =
   | 'useTransition'
   | 'useImperativeHandle'
   | 'useEffectEvent'
+  | 'useOptimistic'
   | 'Custom';
 
 /*
@@ -399,12 +400,15 @@ export const BuiltInUseReducerId = 'BuiltInUseReducer';
 export const BuiltInDispatchId = 'BuiltInDispatch';
 export const BuiltInUseContextHookId = 'BuiltInUseContextHook';
 export const BuiltInUseTransitionId = 'BuiltInUseTransition';
+export const BuiltInUseOptimisticId = 'BuiltInUseOptimistic';
+export const BuiltInSetOptimisticId = 'BuiltInSetOptimistic';
 export const BuiltInStartTransitionId = 'BuiltInStartTransition';
 export const BuiltInFireId = 'BuiltInFire';
 export const BuiltInFireFunctionId = 'BuiltInFireFunction';
 export const BuiltInUseEffectEventId = 'BuiltInUseEffectEvent';
-export const BuiltinEffectEventId = 'BuiltInEffectEventFunction';
+export const BuiltInEffectEventId = 'BuiltInEffectEventFunction';
 export const BuiltInAutodepsId = 'BuiltInAutoDepsId';
+export const BuiltInEventHandlerId = 'BuiltInEventHandlerId';
 
 // See getReanimatedModuleType() in Globals.ts — this is part of supporting Reanimated's ref-like types
 export const ReanimatedSharedValueId = 'ReanimatedSharedValueId';
@@ -1185,6 +1189,25 @@ addObject(BUILTIN_SHAPES, BuiltInUseTransitionId, [
   ],
 ]);
 
+addObject(BUILTIN_SHAPES, BuiltInUseOptimisticId, [
+  ['0', {kind: 'Poly'}],
+  [
+    '1',
+    addFunction(
+      BUILTIN_SHAPES,
+      [],
+      {
+        positionalParams: [],
+        restParam: Effect.Freeze,
+        returnType: PRIMITIVE_TYPE,
+        calleeEffect: Effect.Read,
+        returnValueKind: ValueKind.Primitive,
+      },
+      BuiltInSetOptimisticId,
+    ),
+  ],
+]);
+
 addObject(BUILTIN_SHAPES, BuiltInUseActionStateId, [
   ['0', {kind: 'Poly'}],
   [
@@ -1243,7 +1266,20 @@ addFunction(
     calleeEffect: Effect.ConditionallyMutate,
     returnValueKind: ValueKind.Mutable,
   },
-  BuiltinEffectEventId,
+  BuiltInEffectEventId,
+);
+
+addFunction(
+  BUILTIN_SHAPES,
+  [],
+  {
+    positionalParams: [],
+    restParam: Effect.ConditionallyMutate,
+    returnType: {kind: 'Poly'},
+    calleeEffect: Effect.ConditionallyMutate,
+    returnValueKind: ValueKind.Mutable,
+  },
+  BuiltInEventHandlerId,
 );
 
 /**

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

@@ -11,6 +11,7 @@ import {
   BasicBlock,
   BlockId,
   Instruction,
+  InstructionKind,
   InstructionValue,
   makeInstructionId,
   Pattern,
@@ -32,6 +33,32 @@ export function* eachInstructionLValue(
   yield* eachInstructionValueLValue(instr.value);
 }
 
+export function* eachInstructionLValueWithKind(
+  instr: ReactiveInstruction,
+): Iterable<[Place, InstructionKind]> {
+  switch (instr.value.kind) {
+    case 'DeclareContext':
+    case 'StoreContext':
+    case 'DeclareLocal':
+    case 'StoreLocal': {
+      yield [instr.value.lvalue.place, instr.value.lvalue.kind];
+      break;
+    }
+    case 'Destructure': {
+      const kind = instr.value.lvalue.kind;
+      for (const place of eachPatternOperand(instr.value.lvalue.pattern)) {
+        yield [place, kind];
+      }
+      break;
+    }
+    case 'PostfixUpdate':
+    case 'PrefixUpdate': {
+      yield [instr.value.lvalue, InstructionKind.Reassign];
+      break;
+    }
+  }
+}
+
 export function* eachInstructionValueLValue(
   value: ReactiveValue,
 ): Iterable<Place> {

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

@@ -0,0 +1,114 @@
+/**
+ * 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 {BlockId, computePostDominatorTree, HIRFunction, Place} from '../HIR';
+import {PostDominator} from '../HIR/Dominator';
+
+export type ControlDominators = (id: BlockId) => boolean;
+
+/**
+ * Returns an object that lazily calculates whether particular blocks are controlled
+ * by values of interest. Which values matter are up to the caller.
+ */
+export function createControlDominators(
+  fn: HIRFunction,
+  isControlVariable: (place: Place) => boolean,
+): ControlDominators {
+  const postDominators = computePostDominatorTree(fn, {
+    includeThrowsAsExitNode: false,
+  });
+  const postDominatorFrontierCache = new Map<BlockId, Set<BlockId>>();
+
+  function isControlledBlock(id: BlockId): boolean {
+    let controlBlocks = postDominatorFrontierCache.get(id);
+    if (controlBlocks === undefined) {
+      controlBlocks = postDominatorFrontier(fn, postDominators, id);
+      postDominatorFrontierCache.set(id, controlBlocks);
+    }
+    for (const blockId of controlBlocks) {
+      const controlBlock = fn.body.blocks.get(blockId)!;
+      switch (controlBlock.terminal.kind) {
+        case 'if':
+        case 'branch': {
+          if (isControlVariable(controlBlock.terminal.test)) {
+            return true;
+          }
+          break;
+        }
+        case 'switch': {
+          if (isControlVariable(controlBlock.terminal.test)) {
+            return true;
+          }
+          for (const case_ of controlBlock.terminal.cases) {
+            if (case_.test !== null && isControlVariable(case_.test)) {
+              return true;
+            }
+          }
+          break;
+        }
+      }
+    }
+    return false;
+  }
+
+  return isControlledBlock;
+}
+
+/*
+ * Computes the post-dominator frontier of @param block. These are immediate successors of nodes that
+ * post-dominate @param targetId and from which execution may not reach @param block. Intuitively, these
+ * are the earliest blocks from which execution branches such that it may or may not reach the target block.
+ */
+function postDominatorFrontier(
+  fn: HIRFunction,
+  postDominators: PostDominator<BlockId>,
+  targetId: BlockId,
+): Set<BlockId> {
+  const visited = new Set<BlockId>();
+  const frontier = new Set<BlockId>();
+  const targetPostDominators = postDominatorsOf(fn, postDominators, targetId);
+  for (const blockId of [...targetPostDominators, targetId]) {
+    if (visited.has(blockId)) {
+      continue;
+    }
+    visited.add(blockId);
+    const block = fn.body.blocks.get(blockId)!;
+    for (const pred of block.preds) {
+      if (!targetPostDominators.has(pred)) {
+        // The predecessor does not always reach this block, we found an item on the frontier!
+        frontier.add(pred);
+      }
+    }
+  }
+  return frontier;
+}
+
+function postDominatorsOf(
+  fn: HIRFunction,
+  postDominators: PostDominator<BlockId>,
+  targetId: BlockId,
+): Set<BlockId> {
+  const result = new Set<BlockId>();
+  const visited = new Set<BlockId>();
+  const queue = [targetId];
+  while (queue.length) {
+    const currentId = queue.shift()!;
+    if (visited.has(currentId)) {
+      continue;
+    }
+    visited.add(currentId);
+    const current = fn.body.blocks.get(currentId)!;
+    for (const pred of current.preds) {
+      const predPostDominator = postDominators.get(pred) ?? pred;
+      if (predPostDominator === targetId || result.has(predPostDominator)) {
+        result.add(pred);
+      }
+      queue.push(pred);
+    }
+  }
+  return result;
+}

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

@@ -954,6 +954,7 @@ function applyEffect(
         case ValueKind.Primitive: {
           break;
         }
+        case ValueKind.MaybeFrozen:
         case ValueKind.Frozen: {
           sourceType = 'frozen';
           break;

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

@@ -7,7 +7,6 @@
 
 import {CompilerError} from '..';
 import {
-  BlockId,
   Effect,
   Environment,
   HIRFunction,
@@ -15,14 +14,12 @@ import {
   IdentifierId,
   Instruction,
   Place,
-  computePostDominatorTree,
   evaluatesToStableTypeOrContainer,
   getHookKind,
   isStableType,
   isStableTypeContainer,
   isUseOperator,
 } from '../HIR';
-import {PostDominator} from '../HIR/Dominator';
 import {
   eachInstructionLValue,
   eachInstructionOperand,
@@ -35,6 +32,7 @@ import {
 } from '../ReactiveScopes/InferReactiveScopeVariables';
 import DisjointSet from '../Utils/DisjointSet';
 import {assertExhaustive} from '../Utils/utils';
+import {createControlDominators} from './ControlDominators';
 
 /**
  * Side map to track and propagate sources of stability (i.e. hook calls such as
@@ -212,45 +210,9 @@ export function inferReactivePlaces(fn: HIRFunction): void {
     reactiveIdentifiers.markReactive(place);
   }
 
-  const postDominators = computePostDominatorTree(fn, {
-    includeThrowsAsExitNode: false,
-  });
-  const postDominatorFrontierCache = new Map<BlockId, Set<BlockId>>();
-
-  function isReactiveControlledBlock(id: BlockId): boolean {
-    let controlBlocks = postDominatorFrontierCache.get(id);
-    if (controlBlocks === undefined) {
-      controlBlocks = postDominatorFrontier(fn, postDominators, id);
-      postDominatorFrontierCache.set(id, controlBlocks);
-    }
-    for (const blockId of controlBlocks) {
-      const controlBlock = fn.body.blocks.get(blockId)!;
-      switch (controlBlock.terminal.kind) {
-        case 'if':
-        case 'branch': {
-          if (reactiveIdentifiers.isReactive(controlBlock.terminal.test)) {
-            return true;
-          }
-          break;
-        }
-        case 'switch': {
-          if (reactiveIdentifiers.isReactive(controlBlock.terminal.test)) {
-            return true;
-          }
-          for (const case_ of controlBlock.terminal.cases) {
-            if (
-              case_.test !== null &&
-              reactiveIdentifiers.isReactive(case_.test)
-            ) {
-              return true;
-            }
-          }
-          break;
-        }
-      }
-    }
-    return false;
-  }
+  const isReactiveControlledBlock = createControlDominators(fn, place =>
+    reactiveIdentifiers.isReactive(place),
+  );
 
   do {
     for (const [, block] of fn.body.blocks) {
@@ -411,61 +373,6 @@ export function inferReactivePlaces(fn: HIRFunction): void {
   propagateReactivityToInnerFunctions(fn, true);
 }
 
-/*
- * Computes the post-dominator frontier of @param block. These are immediate successors of nodes that
- * post-dominate @param targetId and from which execution may not reach @param block. Intuitively, these
- * are the earliest blocks from which execution branches such that it may or may not reach the target block.
- */
-function postDominatorFrontier(
-  fn: HIRFunction,
-  postDominators: PostDominator<BlockId>,
-  targetId: BlockId,
-): Set<BlockId> {
-  const visited = new Set<BlockId>();
-  const frontier = new Set<BlockId>();
-  const targetPostDominators = postDominatorsOf(fn, postDominators, targetId);
-  for (const blockId of [...targetPostDominators, targetId]) {
-    if (visited.has(blockId)) {
-      continue;
-    }
-    visited.add(blockId);
-    const block = fn.body.blocks.get(blockId)!;
-    for (const pred of block.preds) {
-      if (!targetPostDominators.has(pred)) {
-        // The predecessor does not always reach this block, we found an item on the frontier!
-        frontier.add(pred);
-      }
-    }
-  }
-  return frontier;
-}
-
-function postDominatorsOf(
-  fn: HIRFunction,
-  postDominators: PostDominator<BlockId>,
-  targetId: BlockId,
-): Set<BlockId> {
-  const result = new Set<BlockId>();
-  const visited = new Set<BlockId>();
-  const queue = [targetId];
-  while (queue.length) {
-    const currentId = queue.shift()!;
-    if (visited.has(currentId)) {
-      continue;
-    }
-    visited.add(currentId);
-    const current = fn.body.blocks.get(currentId)!;
-    for (const pred of current.preds) {
-      const predPostDominator = postDominators.get(pred) ?? pred;
-      if (predPostDominator === targetId || result.has(predPostDominator)) {
-        result.add(pred);
-      }
-      queue.push(pred);
-    }
-  }
-  return result;
-}
-
 class ReactivityMap {
   hasChanges: boolean = false;
   reactive: Set<IdentifierId> = new Set();

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

@@ -1359,8 +1359,6 @@ function codegenInstructionNullable(
       value = null;
     } else {
       lvalue = instr.value.lvalue.pattern;
-      let hasReassign = false;
-      let hasDeclaration = false;
       for (const place of eachPatternOperand(lvalue)) {
         if (
           kind !== InstructionKind.Reassign &&
@@ -1368,26 +1366,6 @@ function codegenInstructionNullable(
         ) {
           cx.temp.set(place.identifier.declarationId, null);
         }
-        const isDeclared = cx.hasDeclared(place.identifier);
-        hasReassign ||= isDeclared;
-        hasDeclaration ||= !isDeclared;
-      }
-      if (hasReassign && hasDeclaration) {
-        CompilerError.invariant(false, {
-          reason:
-            'Encountered a destructuring operation where some identifiers are already declared (reassignments) but others are not (declarations)',
-          description: null,
-          details: [
-            {
-              kind: 'error',
-              loc: instr.loc,
-              message: null,
-            },
-          ],
-          suggestions: null,
-        });
-      } else if (hasReassign) {
-        kind = InstructionKind.Reassign;
       }
       value = codegenPlaceToExpression(cx, instr.value.value);
     }

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

@@ -19,7 +19,11 @@ import {
   promoteTemporary,
 } from '../HIR';
 import {clonePlaceToTemporary} from '../HIR/HIRBuilder';
-import {eachPatternOperand, mapPatternOperands} from '../HIR/visitors';
+import {
+  eachInstructionLValueWithKind,
+  eachPatternOperand,
+  mapPatternOperands,
+} from '../HIR/visitors';
 import {
   ReactiveFunctionTransform,
   Transformed,
@@ -113,6 +117,9 @@ class Visitor extends ReactiveFunctionTransform<State> {
   ): Transformed<ReactiveStatement> {
     this.visitInstruction(instruction, state);
 
+    let instructionsToProcess: Array<ReactiveInstruction> = [instruction];
+    let result: Transformed<ReactiveStatement> = {kind: 'keep'};
+
     if (instruction.value.kind === 'Destructure') {
       const transformed = transformDestructuring(
         state,
@@ -120,7 +127,8 @@ class Visitor extends ReactiveFunctionTransform<State> {
         instruction.value,
       );
       if (transformed) {
-        return {
+        instructionsToProcess = transformed;
+        result = {
           kind: 'replace-many',
           value: transformed.map(instruction => ({
             kind: 'instruction',
@@ -129,7 +137,17 @@ class Visitor extends ReactiveFunctionTransform<State> {
         };
       }
     }
-    return {kind: 'keep'};
+
+    // Update state.declared with declarations from the instruction(s)
+    for (const instr of instructionsToProcess) {
+      for (const [place, kind] of eachInstructionLValueWithKind(instr)) {
+        if (kind !== InstructionKind.Reassign) {
+          state.declared.add(place.identifier.declarationId);
+        }
+      }
+    }
+
+    return result;
   }
 }
 
@@ -144,10 +162,13 @@ function transformDestructuring(
     const isDeclared = state.declared.has(place.identifier.declarationId);
     if (isDeclared) {
       reassigned.add(place.identifier.id);
+    } else {
+      hasDeclaration = true;
     }
-    hasDeclaration ||= !isDeclared;
   }
-  if (reassigned.size === 0 || !hasDeclaration) {
+  if (!hasDeclaration) {
+    // all reassignments
+    destructure.lvalue.kind = InstructionKind.Reassign;
     return null;
   }
   /*

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

@@ -25,6 +25,7 @@ import {
 } from '../HIR/HIR';
 import {
   BuiltInArrayId,
+  BuiltInEventHandlerId,
   BuiltInFunctionId,
   BuiltInJsxId,
   BuiltInMixedReadonlyId,
@@ -471,6 +472,41 @@ function* generateInstructionTypes(
           }
         }
       }
+      if (env.config.enableInferEventHandlers) {
+        if (
+          value.kind === 'JsxExpression' &&
+          value.tag.kind === 'BuiltinTag' &&
+          !value.tag.name.includes('-')
+        ) {
+          /*
+           * Infer event handler types for built-in DOM elements.
+           * Props starting with "on" (e.g., onClick, onSubmit) on primitive tags
+           * are inferred as event handlers. This allows functions with ref access
+           * to be passed to these props, since DOM event handlers are guaranteed
+           * by React to only execute in response to events, never during render.
+           *
+           * We exclude tags with hyphens to avoid web components (custom elements),
+           * which are required by the HTML spec to contain a hyphen. Web components
+           * may call event handler props during their lifecycle methods (e.g.,
+           * connectedCallback), which would be unsafe for ref access.
+           */
+          for (const prop of value.props) {
+            if (
+              prop.kind === 'JsxAttribute' &&
+              prop.name.startsWith('on') &&
+              prop.name.length > 2 &&
+              prop.name[2] === prop.name[2].toUpperCase()
+            ) {
+              yield equation(prop.place.identifier.type, {
+                kind: 'Function',
+                shapeId: BuiltInEventHandlerId,
+                return: makeType(),
+                isConstructor: false,
+              });
+            }
+          }
+        }
+      }
       yield equation(left, {kind: 'Object', shapeId: BuiltInJsxId});
       break;
     }

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

@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import {Result} from '../Utils/Result';
 import {CompilerDiagnostic, CompilerError, Effect} from '..';
 import {ErrorCategory} from '../CompilerError';
 import {
@@ -20,8 +21,8 @@ import {
   isUseStateType,
   BasicBlock,
   isUseRefType,
-  GeneratedSource,
   SourceLocation,
+  ArrayExpression,
 } from '../HIR';
 import {eachInstructionLValue, eachInstructionOperand} from '../HIR/visitors';
 import {isMutable} from '../ReactiveScopes/InferReactiveScopeVariables';
@@ -33,17 +34,26 @@ type DerivationMetadata = {
   typeOfValue: TypeOfValue;
   place: Place;
   sourcesIds: Set<IdentifierId>;
+  isStateSource: boolean;
+};
+
+type EffectMetadata = {
+  effect: HIRFunction;
+  dependencies: ArrayExpression;
 };
 
 type ValidationContext = {
   readonly functions: Map<IdentifierId, FunctionExpression>;
+  readonly candidateDependencies: Map<IdentifierId, ArrayExpression>;
   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>>;
+  readonly effectsCache: Map<IdentifierId, EffectMetadata>;
+  readonly setStateLoads: Map<IdentifierId, IdentifierId | null>;
+  readonly setStateUsages: Map<IdentifierId, Set<SourceLocation>>;
 };
 
+const MAX_FIXPOINT_ITERATIONS = 100;
+
 class DerivationCache {
   hasChanges: boolean = false;
   cache: Map<IdentifierId, DerivationMetadata> = new Map();
@@ -56,6 +66,7 @@ class DerivationCache {
         place: value.place,
         sourcesIds: new Set(value.sourcesIds),
         typeOfValue: value.typeOfValue,
+        isStateSource: value.isStateSource,
       });
     }
   }
@@ -95,41 +106,28 @@ class DerivationCache {
     derivedVar: Place,
     sourcesIds: Set<IdentifierId>,
     typeOfValue: TypeOfValue,
+    isStateSource: boolean,
   ): 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.
-         */
+    let finalIsSource = isStateSource;
+    if (!finalIsSource) {
+      for (const sourceId of sourcesIds) {
+        const sourceMetadata = this.cache.get(sourceId);
         if (
-          sourcePlace.identifier.name === null ||
-          sourcePlace.identifier.name?.kind === 'promoted'
+          sourceMetadata?.isStateSource &&
+          sourceMetadata.place.identifier.name?.kind !== 'named'
         ) {
-          newValue.sourcesIds.add(derivedVar.identifier.id);
-        } else {
-          newValue.sourcesIds.add(sourcePlace.identifier.id);
+          finalIsSource = true;
+          break;
         }
       }
     }
 
-    if (newValue.sourcesIds.size === 0) {
-      newValue.sourcesIds.add(derivedVar.identifier.id);
-    }
-
-    this.cache.set(derivedVar.identifier.id, newValue);
+    this.cache.set(derivedVar.identifier.id, {
+      place: derivedVar,
+      sourcesIds: sourcesIds,
+      typeOfValue: typeOfValue ?? 'ignored',
+      isStateSource: finalIsSource,
+    });
   }
 
   private isDerivationEqual(
@@ -151,6 +149,14 @@ class DerivationCache {
   }
 }
 
+function isNamedIdentifier(place: Place): place is Place & {
+  identifier: {name: NonNullable<Place['identifier']['name']>};
+} {
+  return (
+    place.identifier.name !== null && place.identifier.name.kind === 'named'
+  );
+}
+
 /**
  * Validates that useEffect is not used for derived computations which could/should
  * be performed in render.
@@ -176,25 +182,24 @@ class DerivationCache {
  */
 export function validateNoDerivedComputationsInEffects_exp(
   fn: HIRFunction,
-): void {
+): Result<void, CompilerError> {
   const functions: Map<IdentifierId, FunctionExpression> = new Map();
+  const candidateDependencies: Map<IdentifierId, ArrayExpression> = new Map();
   const derivationCache = new DerivationCache();
   const errors = new CompilerError();
-  const effects: Set<HIRFunction> = new Set();
+  const effectsCache: Map<IdentifierId, EffectMetadata> = new Map();
 
-  const setStateCache: Map<string | undefined | null, Array<Place>> = new Map();
-  const effectSetStateCache: Map<
-    string | undefined | null,
-    Array<Place>
-  > = new Map();
+  const setStateLoads: Map<IdentifierId, IdentifierId> = new Map();
+  const setStateUsages: Map<IdentifierId, Set<SourceLocation>> = new Map();
 
   const context: ValidationContext = {
     functions,
+    candidateDependencies,
     errors,
     derivationCache,
-    effects,
-    setStateCache,
-    effectSetStateCache,
+    effectsCache,
+    setStateLoads,
+    setStateUsages,
   };
 
   if (fn.fnType === 'Hook') {
@@ -202,8 +207,9 @@ export function validateNoDerivedComputationsInEffects_exp(
       if (param.kind === 'Identifier') {
         context.derivationCache.cache.set(param.identifier.id, {
           place: param,
-          sourcesIds: new Set([param.identifier.id]),
+          sourcesIds: new Set(),
           typeOfValue: 'fromProps',
+          isStateSource: true,
         });
       }
     }
@@ -212,13 +218,15 @@ export function validateNoDerivedComputationsInEffects_exp(
     if (props != null && props.kind === 'Identifier') {
       context.derivationCache.cache.set(props.identifier.id, {
         place: props,
-        sourcesIds: new Set([props.identifier.id]),
+        sourcesIds: new Set(),
         typeOfValue: 'fromProps',
+        isStateSource: true,
       });
     }
   }
 
   let isFirstPass = true;
+  let iterationCount = 0;
   do {
     context.derivationCache.takeSnapshot();
 
@@ -231,15 +239,26 @@ export function validateNoDerivedComputationsInEffects_exp(
 
     context.derivationCache.checkForChanges();
     isFirstPass = false;
+    iterationCount++;
+    CompilerError.invariant(iterationCount < MAX_FIXPOINT_ITERATIONS, {
+      reason:
+        '[ValidateNoDerivedComputationsInEffects] Fixpoint iteration failed to converge',
+      description: `Fixpoint iteration exceeded ${MAX_FIXPOINT_ITERATIONS} iterations while tracking derivations. This suggests a cyclic dependency in the derivation cache.`,
+      details: [
+        {
+          kind: 'error',
+          loc: fn.loc,
+          message: `Exceeded ${MAX_FIXPOINT_ITERATIONS} iterations in ValidateNoDerivedComputationsInEffects`,
+        },
+      ],
+    });
   } while (context.derivationCache.snapshot());
 
-  for (const effect of effects) {
-    validateEffect(effect, context);
+  for (const [, effect] of effectsCache) {
+    validateEffect(effect.effect, effect.dependencies, context);
   }
 
-  if (errors.hasAnyErrors()) {
-    throw errors;
-  }
+  return errors.asResult();
 }
 
 function recordPhiDerivations(
@@ -267,6 +286,7 @@ function recordPhiDerivations(
         phi.place,
         sourcesIds,
         typeOfValue,
+        false,
       );
     }
   }
@@ -282,17 +302,69 @@ function joinValue(
   return 'fromPropsAndState';
 }
 
+function getRootSetState(
+  key: IdentifierId,
+  loads: Map<IdentifierId, IdentifierId | null>,
+  visited: Set<IdentifierId> = new Set(),
+): IdentifierId | null {
+  if (visited.has(key)) {
+    return null;
+  }
+  visited.add(key);
+
+  const parentId = loads.get(key);
+
+  if (parentId === undefined) {
+    return null;
+  }
+
+  if (parentId === null) {
+    return key;
+  }
+
+  return getRootSetState(parentId, loads, visited);
+}
+
+function maybeRecordSetState(
+  instr: Instruction,
+  loads: Map<IdentifierId, IdentifierId | null>,
+  usages: Map<IdentifierId, Set<SourceLocation>>,
+): void {
+  for (const operand of eachInstructionLValue(instr)) {
+    if (
+      instr.value.kind === 'LoadLocal' &&
+      loads.has(instr.value.place.identifier.id)
+    ) {
+      loads.set(operand.identifier.id, instr.value.place.identifier.id);
+    } else {
+      if (isSetStateType(operand.identifier)) {
+        // this is a root setState
+        loads.set(operand.identifier.id, null);
+      }
+    }
+
+    const rootSetState = getRootSetState(operand.identifier.id, loads);
+    if (rootSetState !== null && usages.get(rootSetState) === undefined) {
+      usages.set(rootSetState, new Set([operand.loc]));
+    }
+  }
+}
+
 function recordInstructionDerivations(
   instr: Instruction,
   context: ValidationContext,
   isFirstPass: boolean,
 ): void {
+  maybeRecordSetState(instr, context.setStateLoads, context.setStateUsages);
+
   let typeOfValue: TypeOfValue = 'ignored';
+  let isSource: boolean = false;
   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) {
+      recordPhiDerivations(block, context);
       for (const instr of block.instructions) {
         recordInstructionDerivations(instr, context, isFirstPass);
       }
@@ -307,28 +379,37 @@ function recordInstructionDerivations(
       value.args[1].kind === 'Identifier'
     ) {
       const effectFunction = context.functions.get(value.args[0].identifier.id);
-      if (effectFunction != null) {
-        context.effects.add(effectFunction.loweredFunc.func);
+      const deps = context.candidateDependencies.get(
+        value.args[1].identifier.id,
+      );
+      if (effectFunction != null && deps != null) {
+        context.effectsCache.set(value.args[0].identifier.id, {
+          effect: effectFunction.loweredFunc.func,
+          dependencies: deps,
+        });
       }
     } 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');
+      typeOfValue = 'fromState';
+      context.derivationCache.addDerivationEntry(
+        lvalue,
+        new Set(),
+        typeOfValue,
+        true,
+      );
+      return;
     }
+  } else if (value.kind === 'ArrayExpression') {
+    context.candidateDependencies.set(lvalue.identifier.id, value);
   }
 
   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]);
+    if (context.setStateLoads.has(operand.identifier.id)) {
+      const rootSetStateId = getRootSetState(
+        operand.identifier.id,
+        context.setStateLoads,
+      );
+      if (rootSetStateId !== null) {
+        context.setStateUsages.get(rootSetStateId)?.add(operand.loc);
       }
     }
 
@@ -341,9 +422,7 @@ function recordInstructionDerivations(
     }
 
     typeOfValue = joinValue(typeOfValue, operandMetadata.typeOfValue);
-    for (const id of operandMetadata.sourcesIds) {
-      sources.add(id);
-    }
+    sources.add(operand.identifier.id);
   }
 
   if (typeOfValue === 'ignored') {
@@ -351,7 +430,20 @@ function recordInstructionDerivations(
   }
 
   for (const lvalue of eachInstructionLValue(instr)) {
-    context.derivationCache.addDerivationEntry(lvalue, sources, typeOfValue);
+    context.derivationCache.addDerivationEntry(
+      lvalue,
+      sources,
+      typeOfValue,
+      isSource,
+    );
+  }
+
+  if (value.kind === 'FunctionExpression') {
+    /*
+     * We don't want to record effect mutations of FunctionExpressions the mutations will happen in the
+     * function body and we will record them there.
+     */
+    return;
   }
 
   for (const operand of eachInstructionOperand(instr)) {
@@ -378,6 +470,7 @@ function recordInstructionDerivations(
               operand,
               sources,
               typeOfValue,
+              false,
             );
           }
         }
@@ -411,21 +504,196 @@ function recordInstructionDerivations(
   }
 }
 
+type TreeNode = {
+  name: string;
+  typeOfValue: TypeOfValue;
+  isSource: boolean;
+  children: Array<TreeNode>;
+};
+
+function buildTreeNode(
+  sourceId: IdentifierId,
+  context: ValidationContext,
+  visited: Set<string> = new Set(),
+): Array<TreeNode> {
+  const sourceMetadata = context.derivationCache.cache.get(sourceId);
+  if (!sourceMetadata) {
+    return [];
+  }
+
+  if (sourceMetadata.isStateSource && isNamedIdentifier(sourceMetadata.place)) {
+    return [
+      {
+        name: sourceMetadata.place.identifier.name.value,
+        typeOfValue: sourceMetadata.typeOfValue,
+        isSource: sourceMetadata.isStateSource,
+        children: [],
+      },
+    ];
+  }
+
+  const children: Array<TreeNode> = [];
+
+  const namedSiblings: Set<string> = new Set();
+  for (const childId of sourceMetadata.sourcesIds) {
+    CompilerError.invariant(childId !== sourceId, {
+      reason:
+        'Unexpected self-reference: a value should not have itself as a source',
+      description: null,
+      details: [
+        {
+          kind: 'error',
+          loc: sourceMetadata.place.loc,
+          message: null,
+        },
+      ],
+    });
+
+    const childNodes = buildTreeNode(
+      childId,
+      context,
+      new Set([
+        ...visited,
+        ...(isNamedIdentifier(sourceMetadata.place)
+          ? [sourceMetadata.place.identifier.name.value]
+          : []),
+      ]),
+    );
+    if (childNodes) {
+      for (const childNode of childNodes) {
+        if (!namedSiblings.has(childNode.name)) {
+          children.push(childNode);
+          namedSiblings.add(childNode.name);
+        }
+      }
+    }
+  }
+
+  if (
+    isNamedIdentifier(sourceMetadata.place) &&
+    !visited.has(sourceMetadata.place.identifier.name.value)
+  ) {
+    return [
+      {
+        name: sourceMetadata.place.identifier.name.value,
+        typeOfValue: sourceMetadata.typeOfValue,
+        isSource: sourceMetadata.isStateSource,
+        children: children,
+      },
+    ];
+  }
+
+  return children;
+}
+
+function renderTree(
+  node: TreeNode,
+  indent: string = '',
+  isLast: boolean = true,
+  propsSet: Set<string>,
+  stateSet: Set<string>,
+): string {
+  const prefix = indent + (isLast ? '└── ' : '├── ');
+  const childIndent = indent + (isLast ? '    ' : '│   ');
+
+  let result = `${prefix}${node.name}`;
+
+  if (node.isSource) {
+    let typeLabel: string;
+    if (node.typeOfValue === 'fromProps') {
+      propsSet.add(node.name);
+      typeLabel = 'Prop';
+    } else if (node.typeOfValue === 'fromState') {
+      stateSet.add(node.name);
+      typeLabel = 'State';
+    } else {
+      propsSet.add(node.name);
+      stateSet.add(node.name);
+      typeLabel = 'Prop and State';
+    }
+    result += ` (${typeLabel})`;
+  }
+
+  if (node.children.length > 0) {
+    result += '\n';
+    node.children.forEach((child, index) => {
+      const isLastChild = index === node.children.length - 1;
+      result += renderTree(child, childIndent, isLastChild, propsSet, stateSet);
+      if (index < node.children.length - 1) {
+        result += '\n';
+      }
+    });
+  }
+
+  return result;
+}
+
+function getFnLocalDeps(
+  fn: FunctionExpression | undefined,
+): Set<IdentifierId> | undefined {
+  if (!fn) {
+    return undefined;
+  }
+
+  const deps: Set<IdentifierId> = new Set();
+
+  for (const [, block] of fn.loweredFunc.func.body.blocks) {
+    for (const instr of block.instructions) {
+      if (instr.value.kind === 'LoadLocal') {
+        deps.add(instr.value.place.identifier.id);
+      }
+    }
+  }
+
+  return deps;
+}
+
 function validateEffect(
   effectFunction: HIRFunction,
+  dependencies: ArrayExpression,
   context: ValidationContext,
 ): void {
   const seenBlocks: Set<BlockId> = new Set();
 
   const effectDerivedSetStateCalls: Array<{
     value: CallExpression;
-    loc: SourceLocation;
+    id: IdentifierId;
     sourceIds: Set<IdentifierId>;
     typeOfValue: TypeOfValue;
   }> = [];
 
+  const effectSetStateUsages: Map<
+    IdentifierId,
+    Set<SourceLocation>
+  > = new Map();
+
+  // Consider setStates in the effect's dependency array as being part of effectSetStateUsages
+  for (const dep of dependencies.elements) {
+    if (dep.kind === 'Identifier') {
+      const root = getRootSetState(dep.identifier.id, context.setStateLoads);
+      if (root !== null) {
+        effectSetStateUsages.set(root, new Set([dep.loc]));
+      }
+    }
+  }
+
+  let cleanUpFunctionDeps: Set<IdentifierId> | undefined;
+
   const globals: Set<IdentifierId> = new Set();
   for (const block of effectFunction.body.blocks.values()) {
+    /*
+     * if the block is in an effect and is of type return then its an effect's cleanup function
+     * if the cleanup function depends on a value from which effect-set state is derived then
+     * we can't validate
+     */
+    if (
+      block.terminal.kind === 'return' &&
+      block.terminal.returnVariant === 'Explicit'
+    ) {
+      cleanUpFunctionDeps = getFnLocalDeps(
+        context.functions.get(block.terminal.value.identifier.id),
+      );
+    }
     for (const pred of block.preds) {
       if (!seenBlocks.has(pred)) {
         // skip if block has a back edge
@@ -439,19 +707,16 @@ function validateEffect(
         return;
       }
 
+      maybeRecordSetState(instr, context.setStateLoads, effectSetStateUsages);
+
       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 (context.setStateLoads.has(operand.identifier.id)) {
+          const rootSetStateId = getRootSetState(
+            operand.identifier.id,
+            context.setStateLoads,
+          );
+          if (rootSetStateId !== null) {
+            effectSetStateUsages.get(rootSetStateId)?.add(operand.loc);
           }
         }
       }
@@ -462,6 +727,18 @@ function validateEffect(
         instr.value.args.length === 1 &&
         instr.value.args[0].kind === 'Identifier'
       ) {
+        const calleeMetadata = context.derivationCache.cache.get(
+          instr.value.callee.identifier.id,
+        );
+
+        /*
+         * If the setState comes from a source other than local state skip
+         * since the fix is not to calculate in render
+         */
+        if (calleeMetadata?.typeOfValue != 'fromState') {
+          continue;
+        }
+
         const argMetadata = context.derivationCache.cache.get(
           instr.value.args[0].identifier.id,
         );
@@ -469,7 +746,7 @@ function validateEffect(
         if (argMetadata !== undefined) {
           effectDerivedSetStateCalls.push({
             value: instr.value,
-            loc: instr.value.callee.loc,
+            id: instr.value.callee.identifier.id,
             sourceIds: argMetadata.sourcesIds,
             typeOfValue: argMetadata.typeOfValue,
           });
@@ -503,37 +780,74 @@ function validateEffect(
   }
 
   for (const derivedSetStateCall of effectDerivedSetStateCalls) {
+    const rootSetStateCall = getRootSetState(
+      derivedSetStateCall.id,
+      context.setStateLoads,
+    );
+
     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
+      rootSetStateCall !== null &&
+      effectSetStateUsages.has(rootSetStateCall) &&
+      context.setStateUsages.has(rootSetStateCall) &&
+      effectSetStateUsages.get(rootSetStateCall)!.size ===
+        context.setStateUsages.get(rootSetStateCall)!.size - 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(', ');
+      const propsSet = new Set<string>();
+      const stateSet = new Set<string>();
 
-      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: [${derivedDepsStr}]`;
+      const rootNodesMap = new Map<string, TreeNode>();
+      for (const id of derivedSetStateCall.sourceIds) {
+        const nodes = buildTreeNode(id, context);
+        for (const node of nodes) {
+          if (!rootNodesMap.has(node.name)) {
+            rootNodesMap.set(node.name, node);
+          }
+        }
       }
+      const rootNodes = Array.from(rootNodesMap.values());
+
+      const trees = rootNodes.map((node, index) =>
+        renderTree(
+          node,
+          '',
+          index === rootNodes.length - 1,
+          propsSet,
+          stateSet,
+        ),
+      );
+
+      for (const dep of derivedSetStateCall.sourceIds) {
+        if (cleanUpFunctionDeps !== undefined && cleanUpFunctionDeps.has(dep)) {
+          return;
+        }
+      }
+
+      const propsArr = Array.from(propsSet);
+      const stateArr = Array.from(stateSet);
+
+      let rootSources = '';
+      if (propsArr.length > 0) {
+        rootSources += `Props: [${propsArr.join(', ')}]`;
+      }
+      if (stateArr.length > 0) {
+        if (rootSources) rootSources += '\n';
+        rootSources += `State: [${stateArr.join(', ')}]`;
+      }
+
+      const description = `Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user
+
+This setState call is setting a derived value that depends on the following reactive sources:
+
+${rootSources}
+
+Data Flow Tree:
+${trees.join('\n')}
+
+See: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state`;
 
       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`,
+          description: description,
           category: ErrorCategory.EffectDerivationsOfState,
           reason:
             'You might not need an effect. Derive values in render, not effects.',

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

@@ -14,12 +14,14 @@ import {
   BlockId,
   HIRFunction,
   IdentifierId,
+  Identifier,
   Place,
   SourceLocation,
   getHookKindForType,
   isRefValueType,
   isUseRefType,
 } from '../HIR';
+import {BuiltInEventHandlerId} from '../HIR/ObjectShape';
 import {
   eachInstructionOperand,
   eachInstructionValueOperand,
@@ -183,6 +185,11 @@ function refTypeOfType(place: Place): RefAccessType {
   }
 }
 
+function isEventHandlerType(identifier: Identifier): boolean {
+  const type = identifier.type;
+  return type.kind === 'Function' && type.shapeId === BuiltInEventHandlerId;
+}
+
 function tyEqual(a: RefAccessType, b: RefAccessType): boolean {
   if (a.kind !== b.kind) {
     return false;
@@ -519,6 +526,9 @@ function validateNoRefAccessInRenderImpl(
              */
             if (!didError) {
               const isRefLValue = isUseRefType(instr.lvalue.identifier);
+              const isEventHandlerLValue = isEventHandlerType(
+                instr.lvalue.identifier,
+              );
               for (const operand of eachInstructionValueOperand(instr.value)) {
                 /**
                  * By default we check that function call operands are not refs,
@@ -526,29 +536,16 @@ function validateNoRefAccessInRenderImpl(
                  */
                 if (
                   isRefLValue ||
+                  isEventHandlerLValue ||
                   (hookKind != null &&
                     hookKind !== 'useState' &&
                     hookKind !== 'useReducer')
                 ) {
                   /**
-                   * Special cases:
-                   *
-                   * 1. the lvalue is a ref
-                   * In general passing a ref to a function may access that ref
-                   * value during render, so we disallow it.
-                   *
-                   * The main exception is the "mergeRefs" pattern, ie a function
-                   * that accepts multiple refs as arguments (or an array of refs)
-                   * and returns a new, aggregated ref. If the lvalue is a ref,
-                   * we assume that the user is doing this pattern and allow passing
-                   * refs.
-                   *
-                   * Eg `const mergedRef = mergeRefs(ref1, ref2)`
-                   *
-                   * 2. calling hooks
-                   *
-                   * Hooks are independently checked to ensure they don't access refs
-                   * during render.
+                   * Allow passing refs or ref-accessing functions when:
+                   * 1. lvalue is a ref (mergeRefs pattern: `mergeRefs(ref1, ref2)`)
+                   * 2. lvalue is an event handler (DOM events execute outside render)
+                   * 3. calling hooks (independently validated for ref safety)
                    */
                   validateNoDirectRefValueAccess(errors, operand, env);
                 } else if (interpolatedAsJsx.has(instr.lvalue.identifier.id)) {

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

@@ -21,13 +21,17 @@ import {
   isUseRefType,
   isRefValueType,
   Place,
+  Effect,
+  BlockId,
 } from '../HIR';
 import {
   eachInstructionLValue,
   eachInstructionValueOperand,
 } from '../HIR/visitors';
+import {createControlDominators} from '../Inference/ControlDominators';
+import {isMutable} from '../ReactiveScopes/InferReactiveScopeVariables';
 import {Result} from '../Utils/Result';
-import {Iterable_some} from '../Utils/utils';
+import {assertExhaustive, Iterable_some} from '../Utils/utils';
 
 /**
  * Validates against calling setState in the body of an effect (useEffect and friends),
@@ -140,6 +144,8 @@ function getSetStateCall(
   setStateFunctions: Map<IdentifierId, Place>,
   env: Environment,
 ): Place | null {
+  const enableAllowSetStateFromRefsInEffects =
+    env.config.enableAllowSetStateFromRefsInEffects;
   const refDerivedValues: Set<IdentifierId> = new Set();
 
   const isDerivedFromRef = (place: Place): boolean => {
@@ -150,9 +156,38 @@ function getSetStateCall(
     );
   };
 
+  const isRefControlledBlock: (id: BlockId) => boolean =
+    enableAllowSetStateFromRefsInEffects
+      ? createControlDominators(fn, place => isDerivedFromRef(place))
+      : (): boolean => false;
+
   for (const [, block] of fn.body.blocks) {
+    if (enableAllowSetStateFromRefsInEffects) {
+      for (const phi of block.phis) {
+        if (isDerivedFromRef(phi.place)) {
+          continue;
+        }
+        let isPhiDerivedFromRef = false;
+        for (const [, operand] of phi.operands) {
+          if (isDerivedFromRef(operand)) {
+            isPhiDerivedFromRef = true;
+            break;
+          }
+        }
+        if (isPhiDerivedFromRef) {
+          refDerivedValues.add(phi.place.identifier.id);
+        } else {
+          for (const [pred] of phi.operands) {
+            if (isRefControlledBlock(pred)) {
+              refDerivedValues.add(phi.place.identifier.id);
+              break;
+            }
+          }
+        }
+      }
+    }
     for (const instr of block.instructions) {
-      if (env.config.enableAllowSetStateFromRefsInEffects) {
+      if (enableAllowSetStateFromRefsInEffects) {
         const hasRefOperand = Iterable_some(
           eachInstructionValueOperand(instr.value),
           isDerivedFromRef,
@@ -162,6 +197,46 @@ function getSetStateCall(
           for (const lvalue of eachInstructionLValue(instr)) {
             refDerivedValues.add(lvalue.identifier.id);
           }
+          // Ref-derived values can also propagate through mutation
+          for (const operand of eachInstructionValueOperand(instr.value)) {
+            switch (operand.effect) {
+              case Effect.Capture:
+              case Effect.Store:
+              case Effect.ConditionallyMutate:
+              case Effect.ConditionallyMutateIterator:
+              case Effect.Mutate: {
+                if (isMutable(instr, operand)) {
+                  refDerivedValues.add(operand.identifier.id);
+                }
+                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: null,
+                    },
+                  ],
+                  suggestions: null,
+                });
+              }
+              default: {
+                assertExhaustive(
+                  operand.effect,
+                  `Unexpected effect kind \`${operand.effect}\``,
+                );
+              }
+            }
+          }
         }
 
         if (
@@ -203,7 +278,7 @@ function getSetStateCall(
             isSetStateType(callee.identifier) ||
             setStateFunctions.has(callee.identifier.id)
           ) {
-            if (env.config.enableAllowSetStateFromRefsInEffects) {
+            if (enableAllowSetStateFromRefsInEffects) {
               const arg = instr.value.args.at(0);
               if (
                 arg !== undefined &&
@@ -216,6 +291,8 @@ function getSetStateCall(
                  * be needed when initial layout measurements from refs need to be stored in state.
                  */
                 return null;
+              } else if (isRefControlledBlock(block.id)) {
+                continue;
               }
             }
             /*

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

@@ -0,0 +1,206 @@
+/**
+ * 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 {NodePath} from '@babel/traverse';
+import * as t from '@babel/types';
+import {CompilerDiagnostic, CompilerError, ErrorCategory} from '..';
+import {CodegenFunction} from '../ReactiveScopes';
+import {Result} from '../Utils/Result';
+
+/**
+ * IMPORTANT: This validation is only intended for use in unit tests.
+ * It is not intended for use in production.
+ *
+ * This validation is used to ensure that the generated AST has proper source locations
+ * for "important" original nodes.
+ *
+ * There's one big gotcha with this validation: it only works if the "important" original nodes
+ * are not optimized away by the compiler.
+ *
+ * When that scenario happens, we should just update the fixture to not include a node that has no
+ * corresponding node in the generated AST due to being completely removed during compilation.
+ */
+
+/**
+ * Some common node types that are important for coverage tracking.
+ * Based on istanbul-lib-instrument
+ */
+const IMPORTANT_INSTRUMENTED_TYPES = new Set([
+  'ArrowFunctionExpression',
+  'AssignmentPattern',
+  'ObjectMethod',
+  'ExpressionStatement',
+  'BreakStatement',
+  'ContinueStatement',
+  'ReturnStatement',
+  'ThrowStatement',
+  'TryStatement',
+  'VariableDeclarator',
+  'IfStatement',
+  'ForStatement',
+  'ForInStatement',
+  'ForOfStatement',
+  'WhileStatement',
+  'DoWhileStatement',
+  'SwitchStatement',
+  'SwitchCase',
+  'WithStatement',
+  'FunctionDeclaration',
+  'FunctionExpression',
+  'LabeledStatement',
+  'ConditionalExpression',
+  'LogicalExpression',
+]);
+
+/**
+ * Check if a node is a manual memoization call that the compiler optimizes away.
+ * These include useMemo and useCallback calls, which are intentionally removed
+ * by the DropManualMemoization pass.
+ */
+function isManualMemoization(node: t.Node): boolean {
+  // Check if this is a useMemo/useCallback call expression
+  if (t.isCallExpression(node)) {
+    const callee = node.callee;
+    if (t.isIdentifier(callee)) {
+      return callee.name === 'useMemo' || callee.name === 'useCallback';
+    }
+    if (
+      t.isMemberExpression(callee) &&
+      t.isIdentifier(callee.property) &&
+      t.isIdentifier(callee.object)
+    ) {
+      return (
+        callee.object.name === 'React' &&
+        (callee.property.name === 'useMemo' ||
+          callee.property.name === 'useCallback')
+      );
+    }
+  }
+
+  return false;
+}
+
+/**
+ * Create a location key for comparison. We compare by line/column/source,
+ * not by object identity.
+ */
+function locationKey(loc: t.SourceLocation): string {
+  return `${loc.start.line}:${loc.start.column}-${loc.end.line}:${loc.end.column}`;
+}
+
+/**
+ * Validates that important source locations from the original code are preserved
+ * in the generated AST. This ensures that Istanbul coverage instrumentation can
+ * properly map back to the original source code.
+ *
+ * The validator:
+ * 1. Collects locations from "important" nodes in the original AST (those that
+ *    Istanbul instruments for coverage tracking)
+ * 2. Exempts known compiler optimizations (useMemo/useCallback removal)
+ * 3. Verifies that all important locations appear somewhere in the generated AST
+ *
+ * Missing locations can cause Istanbul to fail to track coverage for certain
+ * code paths, leading to inaccurate coverage reports.
+ */
+export function validateSourceLocations(
+  func: NodePath<
+    t.FunctionDeclaration | t.ArrowFunctionExpression | t.FunctionExpression
+  >,
+  generatedAst: CodegenFunction,
+): Result<void, CompilerError> {
+  const errors = new CompilerError();
+
+  // Step 1: Collect important locations from the original source
+  const importantOriginalLocations = new Map<
+    string,
+    {loc: t.SourceLocation; nodeType: string}
+  >();
+
+  func.traverse({
+    enter(path) {
+      const node = path.node;
+
+      // Only track node types that Istanbul instruments
+      if (!IMPORTANT_INSTRUMENTED_TYPES.has(node.type)) {
+        return;
+      }
+
+      // Skip manual memoization that the compiler intentionally removes
+      if (isManualMemoization(node)) {
+        return;
+      }
+
+      // Collect the location if it exists
+      if (node.loc) {
+        const key = locationKey(node.loc);
+        importantOriginalLocations.set(key, {
+          loc: node.loc,
+          nodeType: node.type,
+        });
+      }
+    },
+  });
+
+  // Step 2: Collect all locations from the generated AST
+  const generatedLocations = new Set<string>();
+
+  function collectGeneratedLocations(node: t.Node): void {
+    if (node.loc) {
+      generatedLocations.add(locationKey(node.loc));
+    }
+
+    // Use Babel's VISITOR_KEYS to traverse only actual node properties
+    const keys = t.VISITOR_KEYS[node.type as keyof typeof t.VISITOR_KEYS];
+
+    if (!keys) {
+      return;
+    }
+
+    for (const key of keys) {
+      const value = (node as any)[key];
+
+      if (Array.isArray(value)) {
+        for (const item of value) {
+          if (t.isNode(item)) {
+            collectGeneratedLocations(item);
+          }
+        }
+      } else if (t.isNode(value)) {
+        collectGeneratedLocations(value);
+      }
+    }
+  }
+
+  // Collect from main function body
+  collectGeneratedLocations(generatedAst.body);
+
+  // Collect from outlined functions
+  for (const outlined of generatedAst.outlined) {
+    collectGeneratedLocations(outlined.fn.body);
+  }
+
+  // Step 3: Validate that all important locations are preserved
+  for (const [key, {loc, nodeType}] of importantOriginalLocations) {
+    if (!generatedLocations.has(key)) {
+      errors.pushDiagnostic(
+        CompilerDiagnostic.create({
+          category: ErrorCategory.Todo,
+          reason: 'Important source location missing in generated code',
+          description:
+            `Source location for ${nodeType} is missing in the generated output. This can cause coverage instrumentation ` +
+            `to fail to track this code properly, resulting in inaccurate coverage reports.`,
+        }).withDetails({
+          kind: 'error',
+          loc,
+          message: null,
+        }),
+      );
+    }
+  }
+
+  return errors.asResult();
+}

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

@@ -12,4 +12,5 @@ export {validateNoCapitalizedCalls} from './ValidateNoCapitalizedCalls';
 export {validateNoRefAccessInRender} from './ValidateNoRefAccessInRender';
 export {validateNoSetStateInRender} from './ValidateNoSetStateInRender';
 export {validatePreservedManualMemoization} from './ValidatePreservedManualMemoization';
+export {validateSourceLocations} from './ValidateSourceLocations';
 export {validateUseMemo} from './ValidateUseMemo';

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allow-ref-access-in-async-event-handler-wrapper.expect.md

@@ -0,0 +1,148 @@
+
+## Input
+
+```javascript
+// @enableInferEventHandlers
+import {useRef} from 'react';
+
+// Simulates react-hook-form's handleSubmit
+function handleSubmit<T>(callback: (data: T) => void | Promise<void>) {
+  return (event: any) => {
+    event.preventDefault();
+    callback({} as T);
+  };
+}
+
+// Simulates an upload function
+async function upload(file: any): Promise<{blob: {url: string}}> {
+  return {blob: {url: 'https://example.com/file.jpg'}};
+}
+
+interface SignatureRef {
+  toFile(): any;
+}
+
+function Component() {
+  const ref = useRef<SignatureRef>(null);
+
+  const onSubmit = async (value: any) => {
+    // This should be allowed: accessing ref.current in an async event handler
+    // that's wrapped and passed to onSubmit prop
+    let sigUrl: string;
+    if (value.hasSignature) {
+      const {blob} = await upload(ref.current?.toFile());
+      sigUrl = blob?.url || '';
+    } else {
+      sigUrl = value.signature;
+    }
+    console.log('Signature URL:', sigUrl);
+  };
+
+  return (
+    <form onSubmit={handleSubmit(onSubmit)}>
+      <input type="text" name="signature" />
+      <button type="submit">Submit</button>
+    </form>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableInferEventHandlers
+import { useRef } from "react";
+
+// Simulates react-hook-form's handleSubmit
+function handleSubmit(callback) {
+  const $ = _c(2);
+  let t0;
+  if ($[0] !== callback) {
+    t0 = (event) => {
+      event.preventDefault();
+      callback({} as T);
+    };
+    $[0] = callback;
+    $[1] = t0;
+  } else {
+    t0 = $[1];
+  }
+  return t0;
+}
+
+// Simulates an upload function
+async function upload(file) {
+  const $ = _c(1);
+  let t0;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    t0 = { blob: { url: "https://example.com/file.jpg" } };
+    $[0] = t0;
+  } else {
+    t0 = $[0];
+  }
+  return t0;
+}
+
+interface SignatureRef {
+  toFile(): any;
+}
+
+function Component() {
+  const $ = _c(4);
+  const ref = useRef(null);
+
+  const onSubmit = async (value) => {
+    let sigUrl;
+    if (value.hasSignature) {
+      const { blob } = await upload(ref.current?.toFile());
+      sigUrl = blob?.url || "";
+    } else {
+      sigUrl = value.signature;
+    }
+
+    console.log("Signature URL:", sigUrl);
+  };
+
+  const t0 = handleSubmit(onSubmit);
+  let t1;
+  let t2;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    t1 = <input type="text" name="signature" />;
+    t2 = <button type="submit">Submit</button>;
+    $[0] = t1;
+    $[1] = t2;
+  } else {
+    t1 = $[0];
+    t2 = $[1];
+  }
+  let t3;
+  if ($[2] !== t0) {
+    t3 = (
+      <form onSubmit={t0}>
+        {t1}
+        {t2}
+      </form>
+    );
+    $[2] = t0;
+    $[3] = t3;
+  } else {
+    t3 = $[3];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};
+
+```
+      
+### Eval output
+(kind: ok) <form><input type="text" name="signature"><button type="submit">Submit</button></form>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allow-ref-access-in-async-event-handler-wrapper.tsx

@@ -0,0 +1,48 @@
+// @enableInferEventHandlers
+import {useRef} from 'react';
+
+// Simulates react-hook-form's handleSubmit
+function handleSubmit<T>(callback: (data: T) => void | Promise<void>) {
+  return (event: any) => {
+    event.preventDefault();
+    callback({} as T);
+  };
+}
+
+// Simulates an upload function
+async function upload(file: any): Promise<{blob: {url: string}}> {
+  return {blob: {url: 'https://example.com/file.jpg'}};
+}
+
+interface SignatureRef {
+  toFile(): any;
+}
+
+function Component() {
+  const ref = useRef<SignatureRef>(null);
+
+  const onSubmit = async (value: any) => {
+    // This should be allowed: accessing ref.current in an async event handler
+    // that's wrapped and passed to onSubmit prop
+    let sigUrl: string;
+    if (value.hasSignature) {
+      const {blob} = await upload(ref.current?.toFile());
+      sigUrl = blob?.url || '';
+    } else {
+      sigUrl = value.signature;
+    }
+    console.log('Signature URL:', sigUrl);
+  };
+
+  return (
+    <form onSubmit={handleSubmit(onSubmit)}>
+      <input type="text" name="signature" />
+      <button type="submit">Submit</button>
+    </form>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allow-ref-access-in-event-handler-wrapper.expect.md

@@ -0,0 +1,101 @@
+
+## Input
+
+```javascript
+// @enableInferEventHandlers
+import {useRef} from 'react';
+
+// Simulates react-hook-form's handleSubmit or similar event handler wrappers
+function handleSubmit<T>(callback: (data: T) => void) {
+  return (event: any) => {
+    event.preventDefault();
+    callback({} as T);
+  };
+}
+
+function Component() {
+  const ref = useRef<HTMLInputElement>(null);
+
+  const onSubmit = (data: any) => {
+    // This should be allowed: accessing ref.current in an event handler
+    // that's wrapped by handleSubmit and passed to onSubmit prop
+    if (ref.current !== null) {
+      console.log(ref.current.value);
+    }
+  };
+
+  return (
+    <>
+      <input ref={ref} />
+      <form onSubmit={handleSubmit(onSubmit)}>
+        <button type="submit">Submit</button>
+      </form>
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableInferEventHandlers
+import { useRef } from "react";
+
+// Simulates react-hook-form's handleSubmit or similar event handler wrappers
+function handleSubmit(callback) {
+  const $ = _c(2);
+  let t0;
+  if ($[0] !== callback) {
+    t0 = (event) => {
+      event.preventDefault();
+      callback({} as T);
+    };
+    $[0] = callback;
+    $[1] = t0;
+  } else {
+    t0 = $[1];
+  }
+  return t0;
+}
+
+function Component() {
+  const $ = _c(1);
+  const ref = useRef(null);
+  let t0;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    const onSubmit = (data) => {
+      if (ref.current !== null) {
+        console.log(ref.current.value);
+      }
+    };
+
+    t0 = (
+      <>
+        <input ref={ref} />
+        <form onSubmit={handleSubmit(onSubmit)}>
+          <button type="submit">Submit</button>
+        </form>
+      </>
+    );
+    $[0] = t0;
+  } else {
+    t0 = $[0];
+  }
+  return t0;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};
+
+```
+      
+### Eval output
+(kind: ok) <input><form><button type="submit">Submit</button></form>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/allow-ref-access-in-event-handler-wrapper.tsx

@@ -0,0 +1,36 @@
+// @enableInferEventHandlers
+import {useRef} from 'react';
+
+// Simulates react-hook-form's handleSubmit or similar event handler wrappers
+function handleSubmit<T>(callback: (data: T) => void) {
+  return (event: any) => {
+    event.preventDefault();
+    callback({} as T);
+  };
+}
+
+function Component() {
+  const ref = useRef<HTMLInputElement>(null);
+
+  const onSubmit = (data: any) => {
+    // This should be allowed: accessing ref.current in an event handler
+    // that's wrapped by handleSubmit and passed to onSubmit prop
+    if (ref.current !== null) {
+      console.log(ref.current.value);
+    }
+  };
+
+  return (
+    <>
+      <input ref={ref} />
+      <form onSubmit={handleSubmit(onSubmit)}>
+        <button type="submit">Submit</button>
+      </form>
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};

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

@@ -0,0 +1,86 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+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}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(6);
+  const { value, enabled } = t0;
+  const [localValue, setLocalValue] = useState("");
+  let t1;
+  let t2;
+  if ($[0] !== enabled || $[1] !== value) {
+    t1 = () => {
+      if (enabled) {
+        setLocalValue(value);
+      } else {
+        setLocalValue("disabled");
+      }
+    };
+
+    t2 = [value, enabled];
+    $[0] = enabled;
+    $[1] = value;
+    $[2] = t1;
+    $[3] = t2;
+  } else {
+    t1 = $[2];
+    t2 = $[3];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[4] !== localValue) {
+    t3 = <div>{localValue}</div>;
+    $[4] = localValue;
+    $[5] = t3;
+  } else {
+    t3 = $[5];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ value: "test", enabled: true }],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nProps: [value]\n\nData Flow Tree:\n└── value (Prop)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":9,"column":6,"index":244},"end":{"line":9,"column":19,"index":257},"filename":"derived-state-conditionally-in-effect.ts","identifierName":"setLocalValue"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":16,"column":1,"index":378},"filename":"derived-state-conditionally-in-effect.ts"},"fnName":"Component","memoSlots":6,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) <div>test</div>

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({value, enabled}) {

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

@@ -0,0 +1,78 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+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'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+import { useEffect, useState } from "react";
+
+export default function Component(t0) {
+  const $ = _c(5);
+  const { input: t1 } = t0;
+  const input = t1 === undefined ? "empty" : t1;
+  const [currInput, setCurrInput] = useState(input);
+  let t2;
+  let t3;
+  if ($[0] !== input) {
+    t2 = () => {
+      setCurrInput(input + "local const");
+    };
+    t3 = [input, "local const"];
+    $[0] = input;
+    $[1] = t2;
+    $[2] = t3;
+  } else {
+    t2 = $[1];
+    t3 = $[2];
+  }
+  useEffect(t2, t3);
+  let t4;
+  if ($[3] !== currInput) {
+    t4 = <div>{currInput}</div>;
+    $[3] = currInput;
+    $[4] = t4;
+  } else {
+    t4 = $[4];
+  }
+  return t4;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ input: "test" }],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nProps: [input]\n\nData Flow Tree:\n└── input (Prop)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":9,"column":4,"index":276},"end":{"line":9,"column":16,"index":288},"filename":"derived-state-from-default-props.ts","identifierName":"setCurrInput"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":15,"index":122},"end":{"line":13,"column":1,"index":372},"filename":"derived-state-from-default-props.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) <div>testlocal const</div>

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 export default function Component({input = 'empty'}) {

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

@@ -0,0 +1,77 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+import {useEffect, useState} from 'react';
+
+function Component({shouldChange}) {
+  const [count, setCount] = useState(0);
+
+  useEffect(() => {
+    if (shouldChange) {
+      setCount(count + 1);
+    }
+  }, [count]);
+
+  return <div>{count}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(7);
+  const { shouldChange } = t0;
+  const [count, setCount] = useState(0);
+  let t1;
+  if ($[0] !== count || $[1] !== shouldChange) {
+    t1 = () => {
+      if (shouldChange) {
+        setCount(count + 1);
+      }
+    };
+    $[0] = count;
+    $[1] = shouldChange;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  let t2;
+  if ($[3] !== count) {
+    t2 = [count];
+    $[3] = count;
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[5] !== count) {
+    t3 = <div>{count}</div>;
+    $[5] = count;
+    $[6] = t3;
+  } else {
+    t3 = $[6];
+  }
+  return t3;
+}
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nState: [count]\n\nData Flow Tree:\n└── count (State)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":10,"column":6,"index":237},"end":{"line":10,"column":14,"index":245},"filename":"derived-state-from-local-state-in-effect.ts","identifierName":"setCount"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":5,"column":0,"index":108},"end":{"line":15,"column":1,"index":310},"filename":"derived-state-from-local-state-in-effect.ts"},"fnName":"Component","memoSlots":7,"memoBlocks":3,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 
 import {useEffect, useState} from 'react';
 

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

@@ -0,0 +1,115 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+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'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(12);
+  const { firstName } = t0;
+  const [lastName, setLastName] = useState("Doe");
+  const [fullName, setFullName] = useState("John");
+  let t1;
+  let t2;
+  if ($[0] !== firstName || $[1] !== lastName) {
+    t1 = () => {
+      setFullName(firstName + " " + "D." + " " + lastName);
+    };
+    t2 = [firstName, "D.", lastName];
+    $[0] = firstName;
+    $[1] = lastName;
+    $[2] = t1;
+    $[3] = t2;
+  } else {
+    t1 = $[2];
+    t2 = $[3];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[4] === Symbol.for("react.memo_cache_sentinel")) {
+    t3 = (e) => setLastName(e.target.value);
+    $[4] = t3;
+  } else {
+    t3 = $[4];
+  }
+  let t4;
+  if ($[5] !== lastName) {
+    t4 = <input value={lastName} onChange={t3} />;
+    $[5] = lastName;
+    $[6] = t4;
+  } else {
+    t4 = $[6];
+  }
+  let t5;
+  if ($[7] !== fullName) {
+    t5 = <div>{fullName}</div>;
+    $[7] = fullName;
+    $[8] = t5;
+  } else {
+    t5 = $[8];
+  }
+  let t6;
+  if ($[9] !== t4 || $[10] !== t5) {
+    t6 = (
+      <div>
+        {t4}
+        {t5}
+      </div>
+    );
+    $[9] = t4;
+    $[10] = t5;
+    $[11] = t6;
+  } else {
+    t6 = $[11];
+  }
+  return t6;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ firstName: "John" }],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nProps: [firstName]\nState: [lastName]\n\nData Flow Tree:\n├── firstName (Prop)\n└── lastName (State)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":11,"column":4,"index":297},"end":{"line":11,"column":15,"index":308},"filename":"derived-state-from-prop-local-state-and-component-scope.ts","identifierName":"setFullName"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":20,"column":1,"index":542},"filename":"derived-state-from-prop-local-state-and-component-scope.ts"},"fnName":"Component","memoSlots":12,"memoBlocks":5,"memoValues":6,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) <div><input value="Doe"><div>John D. Doe</div></div>

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({firstName}) {

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

@@ -2,7 +2,7 @@
 ## Input
 
 ```javascript
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({initialName}) {
@@ -29,7 +29,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import { useEffect, useState } from "react";
 
 function Component(t0) {
@@ -79,6 +79,12 @@ export const FIXTURE_ENTRYPOINT = {
 };
 
 ```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":16,"column":1,"index":359},"filename":"derived-state-from-prop-setter-call-outside-effect-no-error.ts"},"fnName":"Component","memoSlots":6,"memoBlocks":3,"memoValues":4,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
       
 ### 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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({initialName}) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-from-prop-setter-ternary.expect.md

@@ -0,0 +1,57 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+
+function Component({value}) {
+  const [checked, setChecked] = useState('');
+
+  useEffect(() => {
+    setChecked(value === '' ? [] : value.split(','));
+  }, [value]);
+
+  return <div>{checked}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+
+function Component(t0) {
+  const $ = _c(5);
+  const { value } = t0;
+  const [checked, setChecked] = useState("");
+  let t1;
+  let t2;
+  if ($[0] !== value) {
+    t1 = () => {
+      setChecked(value === "" ? [] : value.split(","));
+    };
+    t2 = [value];
+    $[0] = value;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] !== checked) {
+    t3 = <div>{checked}</div>;
+    $[3] = checked;
+    $[4] = t3;
+  } else {
+    t3 = $[4];
+  }
+  return t3;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-from-prop-setter-ternary.js

@@ -0,0 +1,11 @@
+// @validateNoDerivedComputationsInEffects_exp
+
+function Component({value}) {
+  const [checked, setChecked] = useState('');
+
+  useEffect(() => {
+    setChecked(value === '' ? [] : value.split(','));
+  }, [value]);
+
+  return <div>{checked}</div>;
+}

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

@@ -2,7 +2,7 @@
 ## Input
 
 ```javascript
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function MockComponent({onSet}) {
@@ -28,7 +28,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import { useEffect, useState } from "react";
 
 function MockComponent(t0) {
@@ -80,6 +80,13 @@ export const FIXTURE_ENTRYPOINT = {
 };
 
 ```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":6,"column":1,"index":211},"filename":"derived-state-from-prop-setter-used-outside-effect-no-error.ts"},"fnName":"MockComponent","memoSlots":2,"memoBlocks":1,"memoValues":1,"prunedMemoBlocks":0,"prunedMemoValues":0}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":8,"column":0,"index":213},"end":{"line":15,"column":1,"index":402},"filename":"derived-state-from-prop-setter-used-outside-effect-no-error.ts"},"fnName":"Component","memoSlots":4,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
       
 ### 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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function MockComponent({onSet}) {

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

@@ -0,0 +1,78 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+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'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(5);
+  const { value } = t0;
+  const [localValue, setLocalValue] = useState("");
+  let t1;
+  let t2;
+  if ($[0] !== value) {
+    t1 = () => {
+      setLocalValue(value);
+      document.title = `Value: ${value}`;
+    };
+    t2 = [value];
+    $[0] = value;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] !== localValue) {
+    t3 = <div>{localValue}</div>;
+    $[3] = localValue;
+    $[4] = t3;
+  } else {
+    t3 = $[4];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ value: "test" }],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nProps: [value]\n\nData Flow Tree:\n└── value (Prop)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":8,"column":4,"index":214},"end":{"line":8,"column":17,"index":227},"filename":"derived-state-from-prop-with-side-effect.ts","identifierName":"setLocalValue"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":13,"column":1,"index":327},"filename":"derived-state-from-prop-with-side-effect.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) <div>test</div>

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({value}) {

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

@@ -2,7 +2,7 @@
 ## Input
 
 ```javascript
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState, useRef} from 'react';
 
 export default function Component({test}) {
@@ -27,7 +27,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import { useEffect, useState, useRef } from "react";
 
 export default function Component(t0) {
@@ -68,6 +68,12 @@ export const FIXTURE_ENTRYPOINT = {
 };
 
 ```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":15,"index":130},"end":{"line":14,"column":1,"index":328},"filename":"derived-state-from-ref-and-state-no-error.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
       
 ### 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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState, useRef} from 'react';
 
 export default function Component({test}) {

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

@@ -0,0 +1,93 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+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'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(6);
+  const { propValue } = t0;
+  const [value, setValue] = useState(null);
+  let t1;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    t1 = function localFunction() {
+      console.log("local function");
+    };
+    $[0] = t1;
+  } else {
+    t1 = $[0];
+  }
+  const localFunction = t1;
+  let t2;
+  let t3;
+  if ($[1] !== propValue) {
+    t2 = () => {
+      setValue(propValue);
+      localFunction();
+    };
+    t3 = [propValue];
+    $[1] = propValue;
+    $[2] = t2;
+    $[3] = t3;
+  } else {
+    t2 = $[2];
+    t3 = $[3];
+  }
+  useEffect(t2, t3);
+  let t4;
+  if ($[4] !== value) {
+    t4 = <div>{value}</div>;
+    $[4] = value;
+    $[5] = t4;
+  } else {
+    t4 = $[5];
+  }
+  return t4;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ propValue: "test" }],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nProps: [propValue]\n\nData Flow Tree:\n└── propValue (Prop)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":12,"column":4,"index":279},"end":{"line":12,"column":12,"index":287},"filename":"effect-contains-local-function-call.ts","identifierName":"setValue"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":17,"column":1,"index":371},"filename":"effect-contains-local-function-call.ts"},"fnName":"Component","memoSlots":6,"memoBlocks":3,"memoValues":4,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) <div>test</div>
+logs: ['local function']

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({propValue}) {

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

@@ -2,7 +2,7 @@
 ## Input
 
 ```javascript
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({propValue, onChange}) {
@@ -25,7 +25,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import { useEffect, useState } from "react";
 
 function Component(t0) {
@@ -70,6 +70,13 @@ export const FIXTURE_ENTRYPOINT = {
 };
 
 ```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":12,"column":1,"index":306},"filename":"effect-contains-prop-function-call-no-error.ts"},"fnName":"Component","memoSlots":7,"memoBlocks":3,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":16,"column":41,"index":402},"end":{"line":16,"column":49,"index":410},"filename":"effect-contains-prop-function-call-no-error.ts"},"fnName":null,"memoSlots":0,"memoBlocks":0,"memoValues":0,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
       
 ### 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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({propValue, onChange}) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/effect-used-in-dep-array-still-errors.expect.md

@@ -0,0 +1,63 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component({prop}) {
+  const [s, setS] = useState(0);
+  useEffect(() => {
+    setS(prop);
+  }, [prop, setS]);
+
+  return <div>{prop}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component(t0) {
+  const $ = _c(5);
+  const { prop } = t0;
+  const [, setS] = useState(0);
+  let t1;
+  let t2;
+  if ($[0] !== prop) {
+    t1 = () => {
+      setS(prop);
+    };
+    t2 = [prop, setS];
+    $[0] = prop;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] !== prop) {
+    t3 = <div>{prop}</div>;
+    $[3] = prop;
+    $[4] = t3;
+  } else {
+    t3 = $[4];
+  }
+  return t3;
+}
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nProps: [prop]\n\nData Flow Tree:\n└── prop (Prop)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":6,"column":4,"index":150},"end":{"line":6,"column":8,"index":154},"filename":"effect-used-in-dep-array-still-errors.ts","identifierName":"setS"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":3,"column":0,"index":64},"end":{"line":10,"column":1,"index":212},"filename":"effect-used-in-dep-array-still-errors.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/effect-used-in-dep-array-still-errors.js

@@ -0,0 +1,10 @@
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component({prop}) {
+  const [s, setS] = useState(0);
+  useEffect(() => {
+    setS(prop);
+  }, [prop, setS]);
+
+  return <div>{prop}</div>;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/effect-with-cleanup-function-depending-on-derived-computation-value.expect.md

@@ -0,0 +1,76 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+import {useEffect, useState} from 'react';
+
+function Component(file: File) {
+  const [imageUrl, setImageUrl] = useState(null);
+
+  /*
+   * Cleaning up the variable or a source of the variable used to setState
+   * inside the effect communicates that we always need to clean up something
+   * which is a valid use case for useEffect. In which case we want to
+   * avoid an throwing
+   */
+  useEffect(() => {
+    const imageUrlPrepared = URL.createObjectURL(file);
+    setImageUrl(imageUrlPrepared);
+    return () => URL.revokeObjectURL(imageUrlPrepared);
+  }, [file]);
+
+  return <Image src={imageUrl} xstyle={styles.imageSizeLimits} />;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+import { useEffect, useState } from "react";
+
+function Component(file) {
+  const $ = _c(5);
+  const [imageUrl, setImageUrl] = useState(null);
+  let t0;
+  let t1;
+  if ($[0] !== file) {
+    t0 = () => {
+      const imageUrlPrepared = URL.createObjectURL(file);
+      setImageUrl(imageUrlPrepared);
+      return () => URL.revokeObjectURL(imageUrlPrepared);
+    };
+    t1 = [file];
+    $[0] = file;
+    $[1] = t0;
+    $[2] = t1;
+  } else {
+    t0 = $[1];
+    t1 = $[2];
+  }
+  useEffect(t0, t1);
+  let t2;
+  if ($[3] !== imageUrl) {
+    t2 = <Image src={imageUrl} xstyle={styles.imageSizeLimits} />;
+    $[3] = imageUrl;
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  return t2;
+}
+
+```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":5,"column":0,"index":108},"end":{"line":21,"column":1,"index":700},"filename":"effect-with-cleanup-function-depending-on-derived-computation-value.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/effect-with-cleanup-function-depending-on-derived-computation-value.js

@@ -0,0 +1,21 @@
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+import {useEffect, useState} from 'react';
+
+function Component(file: File) {
+  const [imageUrl, setImageUrl] = useState(null);
+
+  /*
+   * Cleaning up the variable or a source of the variable used to setState
+   * inside the effect communicates that we always need to clean up something
+   * which is a valid use case for useEffect. In which case we want to
+   * avoid an throwing
+   */
+  useEffect(() => {
+    const imageUrlPrepared = URL.createObjectURL(file);
+    setImageUrl(imageUrlPrepared);
+    return () => URL.revokeObjectURL(imageUrlPrepared);
+  }, [file]);
+
+  return <Image src={imageUrl} xstyle={styles.imageSizeLimits} />;
+}

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

@@ -2,7 +2,7 @@
 ## Input
 
 ```javascript
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({propValue}) {
@@ -25,7 +25,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import { useEffect, useState } from "react";
 
 function Component(t0) {
@@ -65,6 +65,12 @@ export const FIXTURE_ENTRYPOINT = {
 };
 
 ```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":12,"column":1,"index":298},"filename":"effect-with-global-function-call-no-error.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
       
 ### 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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component({propValue}) {

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

@@ -1,49 +0,0 @@
-
-## 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-from-default-props.expect.md

@@ -1,46 +0,0 @@
-
-## 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-local-state-in-effect.expect.md

@@ -1,43 +0,0 @@
-
-## 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-prop-local-state-and-component-scope.expect.md

@@ -1,53 +0,0 @@
-
-## 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-with-side-effect.expect.md

@@ -1,46 +0,0 @@
-
-## 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.effect-contains-local-function-call.expect.md

@@ -1,50 +0,0 @@
-
-## 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.invalid-derived-computation-in-effect.expect.md

@@ -1,48 +0,0 @@
-
-## 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-state-from-computed-props.expect.md

@@ -1,46 +0,0 @@
-
-## 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-destructured-props.expect.md

@@ -1,47 +0,0 @@
-
-## 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/from-props-setstate-in-effect-no-error.expect.md

@@ -0,0 +1,65 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @enableTreatSetIdentifiersAsStateSetters @loggerTestOnly
+
+function Component({setParentState, prop}) {
+  useEffect(() => {
+    setParentState(prop);
+  }, [prop]);
+
+  return <div>{prop}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @enableTreatSetIdentifiersAsStateSetters @loggerTestOnly
+
+function Component(t0) {
+  const $ = _c(7);
+  const { setParentState, prop } = t0;
+  let t1;
+  if ($[0] !== prop || $[1] !== setParentState) {
+    t1 = () => {
+      setParentState(prop);
+    };
+    $[0] = prop;
+    $[1] = setParentState;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  let t2;
+  if ($[3] !== prop) {
+    t2 = [prop];
+    $[3] = prop;
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[5] !== prop) {
+    t3 = <div>{prop}</div>;
+    $[5] = prop;
+    $[6] = t3;
+  } else {
+    t3 = $[6];
+  }
+  return t3;
+}
+
+```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":3,"column":0,"index":105},"end":{"line":9,"column":1,"index":240},"filename":"from-props-setstate-in-effect-no-error.ts"},"fnName":"Component","memoSlots":7,"memoBlocks":3,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/from-props-setstate-in-effect-no-error.js

@@ -0,0 +1,9 @@
+// @validateNoDerivedComputationsInEffects_exp @enableTreatSetIdentifiersAsStateSetters @loggerTestOnly
+
+function Component({setParentState, prop}) {
+  useEffect(() => {
+    setParentState(prop);
+  }, [prop]);
+
+  return <div>{prop}</div>;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/function-expression-mutation-edge-case.expect.md

@@ -0,0 +1,115 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component() {
+  const [foo, setFoo] = useState({});
+  const [bar, setBar] = useState(new Set());
+
+  /*
+   * isChanged is considered context of the effect's function expression,
+   * if we don't bail out of effect mutation derivation tracking, isChanged
+   * will inherit the sources of the effect's function expression.
+   *
+   * This is innacurate and with the multiple passes ends up causing an infinite loop.
+   */
+  useEffect(() => {
+    let isChanged = false;
+
+    const newData = foo.map(val => {
+      bar.someMethod(val);
+      isChanged = true;
+    });
+
+    if (isChanged) {
+      setFoo(newData);
+    }
+  }, [foo, bar]);
+
+  return (
+    <div>
+      {foo}, {bar}
+    </div>
+  );
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component() {
+  const $ = _c(9);
+  let t0;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    t0 = {};
+    $[0] = t0;
+  } else {
+    t0 = $[0];
+  }
+  const [foo, setFoo] = useState(t0);
+  let t1;
+  if ($[1] === Symbol.for("react.memo_cache_sentinel")) {
+    t1 = new Set();
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  const [bar] = useState(t1);
+  let t2;
+  let t3;
+  if ($[2] !== bar || $[3] !== foo) {
+    t2 = () => {
+      let isChanged = false;
+
+      const newData = foo.map((val) => {
+        bar.someMethod(val);
+        isChanged = true;
+      });
+
+      if (isChanged) {
+        setFoo(newData);
+      }
+    };
+
+    t3 = [foo, bar];
+    $[2] = bar;
+    $[3] = foo;
+    $[4] = t2;
+    $[5] = t3;
+  } else {
+    t2 = $[4];
+    t3 = $[5];
+  }
+  useEffect(t2, t3);
+  let t4;
+  if ($[6] !== bar || $[7] !== foo) {
+    t4 = (
+      <div>
+        {foo}, {bar}
+      </div>
+    );
+    $[6] = bar;
+    $[7] = foo;
+    $[8] = t4;
+  } else {
+    t4 = $[8];
+  }
+  return t4;
+}
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nState: [foo, bar]\n\nData Flow Tree:\n└── newData\n    ├── foo (State)\n    └── bar (State)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":23,"column":6,"index":663},"end":{"line":23,"column":12,"index":669},"filename":"function-expression-mutation-edge-case.ts","identifierName":"setFoo"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":3,"column":0,"index":64},"end":{"line":32,"column":1,"index":762},"filename":"function-expression-mutation-edge-case.ts"},"fnName":"Component","memoSlots":9,"memoBlocks":4,"memoValues":5,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/function-expression-mutation-edge-case.js

@@ -0,0 +1,32 @@
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component() {
+  const [foo, setFoo] = useState({});
+  const [bar, setBar] = useState(new Set());
+
+  /*
+   * isChanged is considered context of the effect's function expression,
+   * if we don't bail out of effect mutation derivation tracking, isChanged
+   * will inherit the sources of the effect's function expression.
+   *
+   * This is innacurate and with the multiple passes ends up causing an infinite loop.
+   */
+  useEffect(() => {
+    let isChanged = false;
+
+    const newData = foo.map(val => {
+      bar.someMethod(val);
+      isChanged = true;
+    });
+
+    if (isChanged) {
+      setFoo(newData);
+    }
+  }, [foo, bar]);
+
+  return (
+    <div>
+      {foo}, {bar}
+    </div>
+  );
+}

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

@@ -0,0 +1,80 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+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: [],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+import { useEffect, useState } from "react";
+
+function Component() {
+  const $ = _c(5);
+  const [firstName] = useState("Taylor");
+
+  const [fullName, setFullName] = useState("");
+  let t0;
+  let t1;
+  if ($[0] !== firstName) {
+    t0 = () => {
+      setFullName(firstName + " " + "Swift");
+    };
+    t1 = [firstName, "Swift"];
+    $[0] = firstName;
+    $[1] = t0;
+    $[2] = t1;
+  } else {
+    t0 = $[1];
+    t1 = $[2];
+  }
+  useEffect(t0, t1);
+  let t2;
+  if ($[3] !== fullName) {
+    t2 = <div>{fullName}</div>;
+    $[3] = fullName;
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  return t2;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nState: [firstName]\n\nData Flow Tree:\n└── firstName (State)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":11,"column":4,"index":341},"end":{"line":11,"column":15,"index":352},"filename":"invalid-derived-computation-in-effect.ts","identifierName":"setFullName"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":107},"end":{"line":15,"column":1,"index":445},"filename":"invalid-derived-computation-in-effect.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) <div>Taylor Swift</div>

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 function Component() {

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

@@ -0,0 +1,79 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+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: ']'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+import { useEffect, useState } from "react";
+
+export default function Component(props) {
+  const $ = _c(7);
+  const [displayValue, setDisplayValue] = useState("");
+  let t0;
+  let t1;
+  if ($[0] !== props.prefix || $[1] !== props.suffix || $[2] !== props.value) {
+    t0 = () => {
+      const computed = props.prefix + props.value + props.suffix;
+      setDisplayValue(computed);
+    };
+    t1 = [props.prefix, props.value, props.suffix];
+    $[0] = props.prefix;
+    $[1] = props.suffix;
+    $[2] = props.value;
+    $[3] = t0;
+    $[4] = t1;
+  } else {
+    t0 = $[3];
+    t1 = $[4];
+  }
+  useEffect(t0, t1);
+  let t2;
+  if ($[5] !== displayValue) {
+    t2 = <div>{displayValue}</div>;
+    $[5] = displayValue;
+    $[6] = t2;
+  } else {
+    t2 = $[6];
+  }
+  return t2;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ prefix: "[", value: "test", suffix: "]" }],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nProps: [props]\n\nData Flow Tree:\n└── computed\n    └── props (Prop)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":9,"column":4,"index":295},"end":{"line":9,"column":19,"index":310},"filename":"invalid-derived-state-from-computed-props.ts","identifierName":"setDisplayValue"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":15,"index":122},"end":{"line":13,"column":1,"index":409},"filename":"invalid-derived-state-from-computed-props.ts"},"fnName":"Component","memoSlots":7,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) <div>[test]</div>

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 export default function Component(props) {

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

@@ -0,0 +1,81 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+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'}}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+import { useEffect, useState } from "react";
+
+export default function Component(t0) {
+  const $ = _c(6);
+  const { props } = t0;
+  const [fullName, setFullName] = useState(
+    props.firstName + " " + props.lastName,
+  );
+  let t1;
+  let t2;
+  if ($[0] !== props.firstName || $[1] !== props.lastName) {
+    t1 = () => {
+      setFullName(props.firstName + " " + props.lastName);
+    };
+    t2 = [props.firstName, props.lastName];
+    $[0] = props.firstName;
+    $[1] = props.lastName;
+    $[2] = t1;
+    $[3] = t2;
+  } else {
+    t1 = $[2];
+    t2 = $[3];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[4] !== fullName) {
+    t3 = <div>{fullName}</div>;
+    $[4] = fullName;
+    $[5] = t3;
+  } else {
+    t3 = $[5];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ props: { firstName: "John", lastName: "Doe" } }],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileError","detail":{"options":{"description":"Using an effect triggers an additional render which can hurt performance and user experience, potentially briefly showing stale values to the user\n\nThis setState call is setting a derived value that depends on the following reactive sources:\n\nProps: [props]\n\nData Flow Tree:\n└── props (Prop)\n\nSee: https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state","category":"EffectDerivationsOfState","reason":"You might not need an effect. Derive values in render, not effects.","details":[{"kind":"error","loc":{"start":{"line":10,"column":4,"index":269},"end":{"line":10,"column":15,"index":280},"filename":"invalid-derived-state-from-destructured-props.ts","identifierName":"setFullName"},"message":"This should be computed during render, not in an effect"}]}},"fnLoc":null}
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":15,"index":122},"end":{"line":14,"column":1,"index":397},"filename":"invalid-derived-state-from-destructured-props.ts"},"fnName":"Component","memoSlots":6,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) <div>John Doe</div>

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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState} from 'react';
 
 export default function Component({props}) {

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

@@ -2,7 +2,7 @@
 ## Input
 
 ```javascript
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState, useRef} from 'react';
 
 export default function Component({test}) {
@@ -31,7 +31,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import { useEffect, useState, useRef } from "react";
 
 export default function Component(t0) {
@@ -77,6 +77,12 @@ export const FIXTURE_ENTRYPOINT = {
 };
 
 ```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":15,"index":130},"end":{"line":18,"column":1,"index":386},"filename":"ref-conditional-in-effect-no-error.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
       
 ### 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

@@ -1,4 +1,4 @@
-// @validateNoDerivedComputationsInEffects_exp
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
 import {useEffect, useState, useRef} from 'react';
 
 export default function Component({test}) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/usestate-derived-from-prop-no-show-in-data-flow-tree.expect.md

@@ -0,0 +1,71 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component({prop}) {
+  const [s, setS] = useState();
+  const [second, setSecond] = useState(prop);
+
+  /*
+   * `second` is a source of state. It will inherit the value of `prop` in
+   * the first render, but after that it will no longer be updated when
+   * `prop` changes. So we shouldn't consider `second` as being derived from
+   * `prop`
+   */
+  useEffect(() => {
+    setS(second);
+  }, [second]);
+
+  return <div>{s}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component(t0) {
+  const $ = _c(5);
+  const { prop } = t0;
+  const [s, setS] = useState();
+  const [second] = useState(prop);
+  let t1;
+  let t2;
+  if ($[0] !== second) {
+    t1 = () => {
+      setS(second);
+    };
+    t2 = [second];
+    $[0] = second;
+    $[1] = t1;
+    $[2] = t2;
+  } else {
+    t1 = $[1];
+    t2 = $[2];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[3] !== s) {
+    t3 = <div>{s}</div>;
+    $[3] = s;
+    $[4] = t3;
+  } else {
+    t3 = $[4];
+  }
+  return t3;
+}
+
+```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":3,"column":0,"index":64},"end":{"line":18,"column":1,"index":500},"filename":"usestate-derived-from-prop-no-show-in-data-flow-tree.ts"},"fnName":"Component","memoSlots":5,"memoBlocks":2,"memoValues":3,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/usestate-derived-from-prop-no-show-in-data-flow-tree.js

@@ -0,0 +1,18 @@
+// @validateNoDerivedComputationsInEffects_exp @loggerTestOnly
+
+function Component({prop}) {
+  const [s, setS] = useState();
+  const [second, setSecond] = useState(prop);
+
+  /*
+   * `second` is a source of state. It will inherit the value of `prop` in
+   * the first render, but after that it will no longer be updated when
+   * `prop` changes. So we shouldn't consider `second` as being derived from
+   * `prop`
+   */
+  useEffect(() => {
+    setS(second);
+  }, [second]);
+
+  return <div>{s}</div>;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.ref-value-in-custom-component-event-handler-wrapper.expect.md

@@ -0,0 +1,69 @@
+
+## Input
+
+```javascript
+// @enableInferEventHandlers
+import {useRef} from 'react';
+
+// Simulates a custom component wrapper
+function CustomForm({onSubmit, children}: any) {
+  return <form onSubmit={onSubmit}>{children}</form>;
+}
+
+// Simulates react-hook-form's handleSubmit
+function handleSubmit<T>(callback: (data: T) => void) {
+  return (event: any) => {
+    event.preventDefault();
+    callback({} as T);
+  };
+}
+
+function Component() {
+  const ref = useRef<HTMLInputElement>(null);
+
+  const onSubmit = (data: any) => {
+    // This should error: passing function with ref access to custom component
+    // event handler, even though it would be safe on a native <form>
+    if (ref.current !== null) {
+      console.log(ref.current.value);
+    }
+  };
+
+  return (
+    <>
+      <input ref={ref} />
+      <CustomForm onSubmit={handleSubmit(onSubmit)}>
+        <button type="submit">Submit</button>
+      </CustomForm>
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: Cannot access refs during render
+
+React refs are values that are not needed for rendering. Refs should only be accessed outside of render, such as in event handlers or effects. Accessing a ref value (the `current` property) during render can cause your component not to update as expected (https://react.dev/reference/react/useRef).
+
+error.ref-value-in-custom-component-event-handler-wrapper.ts:31:41
+  29 |     <>
+  30 |       <input ref={ref} />
+> 31 |       <CustomForm onSubmit={handleSubmit(onSubmit)}>
+     |                                          ^^^^^^^^ Passing a ref to a function may read its value during render
+  32 |         <button type="submit">Submit</button>
+  33 |       </CustomForm>
+  34 |     </>
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.ref-value-in-custom-component-event-handler-wrapper.tsx

@@ -0,0 +1,41 @@
+// @enableInferEventHandlers
+import {useRef} from 'react';
+
+// Simulates a custom component wrapper
+function CustomForm({onSubmit, children}: any) {
+  return <form onSubmit={onSubmit}>{children}</form>;
+}
+
+// Simulates react-hook-form's handleSubmit
+function handleSubmit<T>(callback: (data: T) => void) {
+  return (event: any) => {
+    event.preventDefault();
+    callback({} as T);
+  };
+}
+
+function Component() {
+  const ref = useRef<HTMLInputElement>(null);
+
+  const onSubmit = (data: any) => {
+    // This should error: passing function with ref access to custom component
+    // event handler, even though it would be safe on a native <form>
+    if (ref.current !== null) {
+      console.log(ref.current.value);
+    }
+  };
+
+  return (
+    <>
+      <input ref={ref} />
+      <CustomForm onSubmit={handleSubmit(onSubmit)}>
+        <button type="submit">Submit</button>
+      </CustomForm>
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.ref-value-in-event-handler-wrapper.expect.md

@@ -0,0 +1,55 @@
+
+## Input
+
+```javascript
+// @enableInferEventHandlers
+import {useRef} from 'react';
+
+// Simulates a handler wrapper
+function handleClick(value: any) {
+  return () => {
+    console.log(value);
+  };
+}
+
+function Component() {
+  const ref = useRef(null);
+
+  // This should still error: passing ref.current directly to a wrapper
+  // The ref value is accessed during render, not in the event handler
+  return (
+    <>
+      <input ref={ref} />
+      <button onClick={handleClick(ref.current)}>Click</button>
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: Cannot access refs during render
+
+React refs are values that are not needed for rendering. Refs should only be accessed outside of render, such as in event handlers or effects. Accessing a ref value (the `current` property) during render can cause your component not to update as expected (https://react.dev/reference/react/useRef).
+
+error.ref-value-in-event-handler-wrapper.ts:19:35
+  17 |     <>
+  18 |       <input ref={ref} />
+> 19 |       <button onClick={handleClick(ref.current)}>Click</button>
+     |                                    ^^^^^^^^^^^ Cannot access ref value during render
+  20 |     </>
+  21 |   );
+  22 | }
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.ref-value-in-event-handler-wrapper.tsx

@@ -0,0 +1,27 @@
+// @enableInferEventHandlers
+import {useRef} from 'react';
+
+// Simulates a handler wrapper
+function handleClick(value: any) {
+  return () => {
+    console.log(value);
+  };
+}
+
+function Component() {
+  const ref = useRef(null);
+
+  // This should still error: passing ref.current directly to a wrapper
+  // The ref value is accessed during render, not in the event handler
+  return (
+    <>
+      <input ref={ref} />
+      <button onClick={handleClick(ref.current)}>Click</button>
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-missing-source-locations.expect.md

@@ -0,0 +1,224 @@
+
+## Input
+
+```javascript
+// @validateSourceLocations
+import {useEffect, useCallback} from 'react';
+
+function Component({prop1, prop2}) {
+  const x = prop1 + prop2;
+  const y = x * 2;
+  const arr = [x, y];
+  const obj = {x, y};
+  const [a, b] = arr;
+  const {x: c, y: d} = obj;
+
+  useEffect(() => {
+    if (a > 10) {
+      console.log(a);
+    }
+  }, [a]);
+
+  const foo = useCallback(() => {
+    return a + b;
+  }, [a, b]);
+
+  function bar() {
+    return (c + d) * 2;
+  }
+
+  console.log('Hello, world!');
+
+  return [y, foo, bar];
+}
+
+```
+
+
+## Error
+
+```
+Found 13 errors:
+
+Todo: Important source location missing in generated code
+
+Source location for VariableDeclarator is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:5:8
+  3 |
+  4 | function Component({prop1, prop2}) {
+> 5 |   const x = prop1 + prop2;
+    |         ^^^^^^^^^^^^^^^^^
+  6 |   const y = x * 2;
+  7 |   const arr = [x, y];
+  8 |   const obj = {x, y};
+
+Todo: Important source location missing in generated code
+
+Source location for VariableDeclarator is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:6:8
+  4 | function Component({prop1, prop2}) {
+  5 |   const x = prop1 + prop2;
+> 6 |   const y = x * 2;
+    |         ^^^^^^^^^
+  7 |   const arr = [x, y];
+  8 |   const obj = {x, y};
+  9 |   const [a, b] = arr;
+
+Todo: Important source location missing in generated code
+
+Source location for VariableDeclarator is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:7:8
+   5 |   const x = prop1 + prop2;
+   6 |   const y = x * 2;
+>  7 |   const arr = [x, y];
+     |         ^^^^^^^^^^^^
+   8 |   const obj = {x, y};
+   9 |   const [a, b] = arr;
+  10 |   const {x: c, y: d} = obj;
+
+Todo: Important source location missing in generated code
+
+Source location for VariableDeclarator is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:8:8
+   6 |   const y = x * 2;
+   7 |   const arr = [x, y];
+>  8 |   const obj = {x, y};
+     |         ^^^^^^^^^^^^
+   9 |   const [a, b] = arr;
+  10 |   const {x: c, y: d} = obj;
+  11 |
+
+Todo: Important source location missing in generated code
+
+Source location for VariableDeclarator is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:9:8
+   7 |   const arr = [x, y];
+   8 |   const obj = {x, y};
+>  9 |   const [a, b] = arr;
+     |         ^^^^^^^^^^^^
+  10 |   const {x: c, y: d} = obj;
+  11 |
+  12 |   useEffect(() => {
+
+Todo: Important source location missing in generated code
+
+Source location for VariableDeclarator is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:10:8
+   8 |   const obj = {x, y};
+   9 |   const [a, b] = arr;
+> 10 |   const {x: c, y: d} = obj;
+     |         ^^^^^^^^^^^^^^^^^^
+  11 |
+  12 |   useEffect(() => {
+  13 |     if (a > 10) {
+
+Todo: Important source location missing in generated code
+
+Source location for ExpressionStatement is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:12:2
+  10 |   const {x: c, y: d} = obj;
+  11 |
+> 12 |   useEffect(() => {
+     |   ^^^^^^^^^^^^^^^^^
+> 13 |     if (a > 10) {
+     | ^^^^^^^^^^^^^^^^^
+> 14 |       console.log(a);
+     | ^^^^^^^^^^^^^^^^^
+> 15 |     }
+     | ^^^^^^^^^^^^^^^^^
+> 16 |   }, [a]);
+     | ^^^^^^^^^^^
+  17 |
+  18 |   const foo = useCallback(() => {
+  19 |     return a + b;
+
+Todo: Important source location missing in generated code
+
+Source location for ExpressionStatement is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:14:6
+  12 |   useEffect(() => {
+  13 |     if (a > 10) {
+> 14 |       console.log(a);
+     |       ^^^^^^^^^^^^^^^
+  15 |     }
+  16 |   }, [a]);
+  17 |
+
+Todo: Important source location missing in generated code
+
+Source location for VariableDeclarator is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:18:8
+  16 |   }, [a]);
+  17 |
+> 18 |   const foo = useCallback(() => {
+     |         ^^^^^^^^^^^^^^^^^^^^^^^^^
+> 19 |     return a + b;
+     | ^^^^^^^^^^^^^^^^^
+> 20 |   }, [a, b]);
+     | ^^^^^^^^^^^^^
+  21 |
+  22 |   function bar() {
+  23 |     return (c + d) * 2;
+
+Todo: Important source location missing in generated code
+
+Source location for ReturnStatement is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:19:4
+  17 |
+  18 |   const foo = useCallback(() => {
+> 19 |     return a + b;
+     |     ^^^^^^^^^^^^^
+  20 |   }, [a, b]);
+  21 |
+  22 |   function bar() {
+
+Todo: Important source location missing in generated code
+
+Source location for ReturnStatement is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:23:4
+  21 |
+  22 |   function bar() {
+> 23 |     return (c + d) * 2;
+     |     ^^^^^^^^^^^^^^^^^^^
+  24 |   }
+  25 |
+  26 |   console.log('Hello, world!');
+
+Todo: Important source location missing in generated code
+
+Source location for ExpressionStatement is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:26:2
+  24 |   }
+  25 |
+> 26 |   console.log('Hello, world!');
+     |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  27 |
+  28 |   return [y, foo, bar];
+  29 | }
+
+Todo: Important source location missing in generated code
+
+Source location for ReturnStatement is missing in the generated output. This can cause coverage instrumentation to fail to track this code properly, resulting in inaccurate coverage reports..
+
+error.todo-missing-source-locations.ts:28:2
+  26 |   console.log('Hello, world!');
+  27 |
+> 28 |   return [y, foo, bar];
+     |   ^^^^^^^^^^^^^^^^^^^^^
+  29 | }
+  30 |
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-missing-source-locations.js

@@ -0,0 +1,29 @@
+// @validateSourceLocations
+import {useEffect, useCallback} from 'react';
+
+function Component({prop1, prop2}) {
+  const x = prop1 + prop2;
+  const y = x * 2;
+  const arr = [x, y];
+  const obj = {x, y};
+  const [a, b] = arr;
+  const {x: c, y: d} = obj;
+
+  useEffect(() => {
+    if (a > 10) {
+      console.log(a);
+    }
+  }, [a]);
+
+  const foo = useCallback(() => {
+    return a + b;
+  }, [a, b]);
+
+  function bar() {
+    return (c + d) * 2;
+  }
+
+  console.log('Hello, world!');
+
+  return [y, foo, bar];
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/repro-destructure-from-prop-with-default-value.expect.md

@@ -0,0 +1,45 @@
+
+## Input
+
+```javascript
+export function useFormatRelativeTime(opts = {}) {
+  const {timeZone, minimal} = opts;
+  const format = useCallback(function formatWithUnit() {}, [minimal]);
+  // We previously recorded `{timeZone}` as capturing timeZone into the object,
+  // then assumed that dateTimeFormat() mutates that object,
+  // which in turn could mutate timeZone and the object it came from,
+  // which meanteans that the value `minimal` is derived from can change.
+  //
+  // The fix was to record a Capture from a maybefrozen value as an ImmutableCapture
+  // which doesn't propagate mutations
+  dateTimeFormat({timeZone});
+  return format;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+export function useFormatRelativeTime(t0) {
+  const $ = _c(1);
+  const opts = t0 === undefined ? {} : t0;
+  const { timeZone, minimal } = opts;
+  let t1;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    t1 = function formatWithUnit() {};
+    $[0] = t1;
+  } else {
+    t1 = $[0];
+  }
+  const format = t1;
+
+  dateTimeFormat({ timeZone });
+  return format;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/repro-destructure-from-prop-with-default-value.js

@@ -0,0 +1,13 @@
+export function useFormatRelativeTime(opts = {}) {
+  const {timeZone, minimal} = opts;
+  const format = useCallback(function formatWithUnit() {}, [minimal]);
+  // We previously recorded `{timeZone}` as capturing timeZone into the object,
+  // then assumed that dateTimeFormat() mutates that object,
+  // which in turn could mutate timeZone and the object it came from,
+  // which meanteans that the value `minimal` is derived from can change.
+  //
+  // The fix was to record a Capture from a maybefrozen value as an ImmutableCapture
+  // which doesn't propagate mutations
+  dateTimeFormat({timeZone});
+  return format;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/preserve-use-callback-stable-built-ins.expect.md

@@ -0,0 +1,91 @@
+
+## Input
+
+```javascript
+// @validatePreserveExistingMemoizationGuarantees
+import {
+  useCallback,
+  useTransition,
+  useState,
+  useOptimistic,
+  useActionState,
+  useRef,
+  useReducer,
+} from 'react';
+
+function useFoo() {
+  const [s, setState] = useState();
+  const ref = useRef(null);
+  const [t, startTransition] = useTransition();
+  const [u, addOptimistic] = useOptimistic();
+  const [v, dispatch] = useReducer(() => {}, null);
+  const [isPending, dispatchAction] = useActionState(() => {}, null);
+
+  return useCallback(() => {
+    dispatch();
+    startTransition(() => {});
+    addOptimistic();
+    setState(null);
+    dispatchAction();
+    ref.current = true;
+  }, []);
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validatePreserveExistingMemoizationGuarantees
+import {
+  useCallback,
+  useTransition,
+  useState,
+  useOptimistic,
+  useActionState,
+  useRef,
+  useReducer,
+} from "react";
+
+function useFoo() {
+  const $ = _c(1);
+  const [, setState] = useState();
+  const ref = useRef(null);
+  const [, startTransition] = useTransition();
+  const [, addOptimistic] = useOptimistic();
+  const [, dispatch] = useReducer(_temp, null);
+  const [, dispatchAction] = useActionState(_temp2, null);
+  let t0;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    t0 = () => {
+      dispatch();
+      startTransition(_temp3);
+      addOptimistic();
+      setState(null);
+      dispatchAction();
+      ref.current = true;
+    };
+    $[0] = t0;
+  } else {
+    t0 = $[0];
+  }
+  return t0;
+}
+function _temp3() {}
+function _temp2() {}
+function _temp() {}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [],
+};
+
+```
+      
+### Eval output
+(kind: ok) "[[ function params=0 ]]"

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/preserve-use-callback-stable-built-ins.ts

@@ -0,0 +1,33 @@
+// @validatePreserveExistingMemoizationGuarantees
+import {
+  useCallback,
+  useTransition,
+  useState,
+  useOptimistic,
+  useActionState,
+  useRef,
+  useReducer,
+} from 'react';
+
+function useFoo() {
+  const [s, setState] = useState();
+  const ref = useRef(null);
+  const [t, startTransition] = useTransition();
+  const [u, addOptimistic] = useOptimistic();
+  const [v, dispatch] = useReducer(() => {}, null);
+  const [isPending, dispatchAction] = useActionState(() => {}, null);
+
+  return useCallback(() => {
+    dispatch();
+    startTransition(() => {});
+    addOptimistic();
+    setState(null);
+    dispatchAction();
+    ref.current = true;
+  }, []);
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-invalid-destructuring-reassignment-undefined-variable.expect.md

@@ -0,0 +1,162 @@
+
+## Input
+
+```javascript
+// @flow @compilationMode:"infer"
+'use strict';
+
+function getWeekendDays(user) {
+  return [0, 6];
+}
+
+function getConfig(weekendDays) {
+  return [1, 5];
+}
+
+component Calendar(user, defaultFirstDay, currentDate, view) {
+  const weekendDays = getWeekendDays(user);
+  let firstDay = defaultFirstDay;
+  let daysToDisplay = 7;
+  if (view === 'week') {
+    let lastDay;
+    // this assignment produces invalid code
+    [firstDay, lastDay] = getConfig(weekendDays);
+    daysToDisplay = ((7 + lastDay - firstDay) % 7) + 1;
+  } else if (view === 'day') {
+    firstDay = currentDate.getDayOfWeek();
+    daysToDisplay = 1;
+  }
+
+  return [currentDate, firstDay, daysToDisplay];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Calendar,
+  params: [
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: {getDayOfWeek: () => 3},
+      view: 'week',
+    },
+  ],
+  sequentialRenders: [
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: {getDayOfWeek: () => 3},
+      view: 'week',
+    },
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: {getDayOfWeek: () => 3},
+      view: 'day',
+    },
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+"use strict";
+import { c as _c } from "react/compiler-runtime";
+
+function getWeekendDays(user) {
+  return [0, 6];
+}
+
+function getConfig(weekendDays) {
+  return [1, 5];
+}
+
+function Calendar(t0) {
+  const $ = _c(12);
+  const { user, defaultFirstDay, currentDate, view } = t0;
+  let daysToDisplay;
+  let firstDay;
+  if (
+    $[0] !== currentDate ||
+    $[1] !== defaultFirstDay ||
+    $[2] !== user ||
+    $[3] !== view
+  ) {
+    const weekendDays = getWeekendDays(user);
+    firstDay = defaultFirstDay;
+    daysToDisplay = 7;
+    if (view === "week") {
+      let lastDay;
+
+      [firstDay, lastDay] = getConfig(weekendDays);
+      daysToDisplay = ((7 + lastDay - firstDay) % 7) + 1;
+    } else {
+      if (view === "day") {
+        let t1;
+        if ($[6] !== currentDate) {
+          t1 = currentDate.getDayOfWeek();
+          $[6] = currentDate;
+          $[7] = t1;
+        } else {
+          t1 = $[7];
+        }
+        firstDay = t1;
+        daysToDisplay = 1;
+      }
+    }
+    $[0] = currentDate;
+    $[1] = defaultFirstDay;
+    $[2] = user;
+    $[3] = view;
+    $[4] = daysToDisplay;
+    $[5] = firstDay;
+  } else {
+    daysToDisplay = $[4];
+    firstDay = $[5];
+  }
+  let t1;
+  if ($[8] !== currentDate || $[9] !== daysToDisplay || $[10] !== firstDay) {
+    t1 = [currentDate, firstDay, daysToDisplay];
+    $[8] = currentDate;
+    $[9] = daysToDisplay;
+    $[10] = firstDay;
+    $[11] = t1;
+  } else {
+    t1 = $[11];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Calendar,
+  params: [
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: { getDayOfWeek: () => 3 },
+      view: "week",
+    },
+  ],
+
+  sequentialRenders: [
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: { getDayOfWeek: () => 3 },
+      view: "week",
+    },
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: { getDayOfWeek: () => 3 },
+      view: "day",
+    },
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) [{"getDayOfWeek":"[[ function params=0 ]]"},1,5]
+[{"getDayOfWeek":"[[ function params=0 ]]"},3,1]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-invalid-destructuring-reassignment-undefined-variable.js

@@ -0,0 +1,53 @@
+// @flow @compilationMode:"infer"
+'use strict';
+
+function getWeekendDays(user) {
+  return [0, 6];
+}
+
+function getConfig(weekendDays) {
+  return [1, 5];
+}
+
+component Calendar(user, defaultFirstDay, currentDate, view) {
+  const weekendDays = getWeekendDays(user);
+  let firstDay = defaultFirstDay;
+  let daysToDisplay = 7;
+  if (view === 'week') {
+    let lastDay;
+    // this assignment produces invalid code
+    [firstDay, lastDay] = getConfig(weekendDays);
+    daysToDisplay = ((7 + lastDay - firstDay) % 7) + 1;
+  } else if (view === 'day') {
+    firstDay = currentDate.getDayOfWeek();
+    daysToDisplay = 1;
+  }
+
+  return [currentDate, firstDay, daysToDisplay];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Calendar,
+  params: [
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: {getDayOfWeek: () => 3},
+      view: 'week',
+    },
+  ],
+  sequentialRenders: [
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: {getDayOfWeek: () => 3},
+      view: 'week',
+    },
+    {
+      user: {},
+      defaultFirstDay: 1,
+      currentDate: {getDayOfWeek: () => 3},
+      view: 'day',
+    },
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/valid-setState-in-useEffect-controlled-by-ref-value.expect.md

@@ -0,0 +1,117 @@
+
+## Input
+
+```javascript
+// @validateNoSetStateInEffects @enableAllowSetStateFromRefsInEffects @loggerTestOnly @compilationMode:"infer"
+import {useState, useRef, useEffect} from 'react';
+
+function Component({x, y}) {
+  const previousXRef = useRef(null);
+  const previousYRef = useRef(null);
+
+  const [data, setData] = useState(null);
+
+  useEffect(() => {
+    const previousX = previousXRef.current;
+    previousXRef.current = x;
+    const previousY = previousYRef.current;
+    previousYRef.current = y;
+    if (!areEqual(x, previousX) || !areEqual(y, previousY)) {
+      const data = load({x, y});
+      setData(data);
+    }
+  }, [x, y]);
+
+  return data;
+}
+
+function areEqual(a, b) {
+  return a === b;
+}
+
+function load({x, y}) {
+  return x * y;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 0, y: 0}],
+  sequentialRenders: [
+    {x: 0, y: 0},
+    {x: 1, y: 0},
+    {x: 1, y: 1},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoSetStateInEffects @enableAllowSetStateFromRefsInEffects @loggerTestOnly @compilationMode:"infer"
+import { useState, useRef, useEffect } from "react";
+
+function Component(t0) {
+  const $ = _c(4);
+  const { x, y } = t0;
+  const previousXRef = useRef(null);
+  const previousYRef = useRef(null);
+
+  const [data, setData] = useState(null);
+  let t1;
+  let t2;
+  if ($[0] !== x || $[1] !== y) {
+    t1 = () => {
+      const previousX = previousXRef.current;
+      previousXRef.current = x;
+      const previousY = previousYRef.current;
+      previousYRef.current = y;
+      if (!areEqual(x, previousX) || !areEqual(y, previousY)) {
+        const data_0 = load({ x, y });
+        setData(data_0);
+      }
+    };
+
+    t2 = [x, y];
+    $[0] = x;
+    $[1] = y;
+    $[2] = t1;
+    $[3] = t2;
+  } else {
+    t1 = $[2];
+    t2 = $[3];
+  }
+  useEffect(t1, t2);
+  return data;
+}
+
+function areEqual(a, b) {
+  return a === b;
+}
+
+function load({ x, y }) {
+  return x * y;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ x: 0, y: 0 }],
+  sequentialRenders: [
+    { x: 0, y: 0 },
+    { x: 1, y: 0 },
+    { x: 1, y: 1 },
+  ],
+};
+
+```
+
+## Logs
+
+```
+{"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":163},"end":{"line":22,"column":1,"index":631},"filename":"valid-setState-in-useEffect-controlled-by-ref-value.ts"},"fnName":"Component","memoSlots":4,"memoBlocks":1,"memoValues":2,"prunedMemoBlocks":0,"prunedMemoValues":0}
+```
+      
+### Eval output
+(kind: ok) 0
+0
+1

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/valid-setState-in-useEffect-controlled-by-ref-value.js

@@ -0,0 +1,40 @@
+// @validateNoSetStateInEffects @enableAllowSetStateFromRefsInEffects @loggerTestOnly @compilationMode:"infer"
+import {useState, useRef, useEffect} from 'react';
+
+function Component({x, y}) {
+  const previousXRef = useRef(null);
+  const previousYRef = useRef(null);
+
+  const [data, setData] = useState(null);
+
+  useEffect(() => {
+    const previousX = previousXRef.current;
+    previousXRef.current = x;
+    const previousY = previousYRef.current;
+    previousYRef.current = y;
+    if (!areEqual(x, previousX) || !areEqual(y, previousY)) {
+      const data = load({x, y});
+      setData(data);
+    }
+  }, [x, y]);
+
+  return data;
+}
+
+function areEqual(a, b) {
+  return a === b;
+}
+
+function load({x, y}) {
+  return x * y;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{x: 0, y: 0}],
+  sequentialRenders: [
+    {x: 0, y: 0},
+    {x: 1, y: 0},
+    {x: 1, y: 1},
+  ],
+};

compiler/packages/snap/src/fixture-utils.ts

@@ -44,6 +44,21 @@ function stripExtension(filename: string, extensions: Array<string>): string {
   return filename;
 }
 
+/**
+ * Strip all extensions from a filename
+ * e.g., "foo.expect.md" -> "foo"
+ */
+function stripAllExtensions(filename: string): string {
+  let result = filename;
+  while (true) {
+    const extension = path.extname(result);
+    if (extension === '') {
+      return result;
+    }
+    result = path.basename(result, extension);
+  }
+}
+
 export async function readTestFilter(): Promise<TestFilter | null> {
   if (!(await exists(FILTER_PATH))) {
     throw new Error(`testfilter file not found at \`${FILTER_PATH}\``);
@@ -111,11 +126,25 @@ async function readInputFixtures(
   } else {
     inputFiles = (
       await Promise.all(
-        filter.paths.map(pattern =>
-          glob.glob(`${pattern}{${INPUT_EXTENSIONS.join(',')}}`, {
+        filter.paths.map(pattern => {
+          // If the pattern already has an extension other than .expect.md,
+          // search for the pattern directly. Otherwise, search for the
+          // pattern with the expected input extensions added.
+          // Eg
+          // `alias-while` => search for `alias-while{.js,.jsx,.ts,.tsx}`
+          // `alias-while.js` => search as-is
+          // `alias-while.expect.md` => search for `alias-while{.js,.jsx,.ts,.tsx}`
+          const basename = path.basename(pattern);
+          const basenameWithoutExt = stripAllExtensions(basename);
+          const hasExtension = basename !== basenameWithoutExt;
+          const globPattern =
+            hasExtension && !pattern.endsWith(SNAPSHOT_EXTENSION)
+              ? pattern
+              : `${basenameWithoutExt}{${INPUT_EXTENSIONS.join(',')}}`;
+          return glob.glob(globPattern, {
             cwd: rootDir,
-          }),
-        ),
+          });
+        }),
       )
     ).flat();
   }
@@ -150,11 +179,13 @@ async function readOutputFixtures(
   } else {
     outputFiles = (
       await Promise.all(
-        filter.paths.map(pattern =>
-          glob.glob(`${pattern}${SNAPSHOT_EXTENSION}`, {
+        filter.paths.map(pattern => {
+          // Strip all extensions and find matching .expect.md files
+          const basenameWithoutExt = stripAllExtensions(pattern);
+          return glob.glob(`${basenameWithoutExt}${SNAPSHOT_EXTENSION}`, {
             cwd: rootDir,
-          }),
-        ),
+          });
+        }),
       )
     ).flat();
   }

compiler/packages/snap/src/runner.ts

@@ -35,6 +35,7 @@ type RunnerOptions = {
   watch: boolean;
   filter: boolean;
   update: boolean;
+  pattern?: string;
 };
 
 const opts: RunnerOptions = yargs
@@ -62,9 +63,15 @@ const opts: RunnerOptions = yargs
     'Only run fixtures which match the contents of testfilter.txt',
   )
   .default('filter', false)
+  .string('pattern')
+  .alias('p', 'pattern')
+  .describe(
+    'pattern',
+    'Optional glob pattern to filter fixtures (e.g., "error.*", "use-memo")',
+  )
   .help('help')
   .strict()
-  .parseSync(hideBin(process.argv));
+  .parseSync(hideBin(process.argv)) as RunnerOptions;
 
 /**
  * Do a test run and return the test results
@@ -171,7 +178,13 @@ export async function main(opts: RunnerOptions): Promise<void> {
   worker.getStderr().pipe(process.stderr);
   worker.getStdout().pipe(process.stdout);
 
-  if (opts.watch) {
+  // If pattern is provided, force watch mode off and use pattern filter
+  const shouldWatch = opts.watch && opts.pattern == null;
+  if (opts.watch && opts.pattern != null) {
+    console.warn('NOTE: --watch is ignored when a --pattern is supplied');
+  }
+
+  if (shouldWatch) {
     makeWatchRunner(state => onChange(worker, state), opts.filter);
     if (opts.filter) {
       /**
@@ -216,7 +229,18 @@ export async function main(opts: RunnerOptions): Promise<void> {
             try {
               execSync('yarn build', {cwd: PROJECT_ROOT});
               console.log('Built compiler successfully with tsup');
-              const testFilter = opts.filter ? await readTestFilter() : null;
+
+              // Determine which filter to use
+              let testFilter: TestFilter | null = null;
+              if (opts.pattern) {
+                testFilter = {
+                  debug: true,
+                  paths: [opts.pattern],
+                };
+              } else if (opts.filter) {
+                testFilter = await readTestFilter();
+              }
+
               const results = await runFixtures(worker, testFilter, 0);
               if (opts.update) {
                 update(results);

package.json

@@ -152,6 +152,7 @@
     "download-build-in-codesandbox-ci": "yarn build --type=node react/index react.react-server react-dom/index react-dom/client react-dom/src/server react-dom/test-utils react-dom.react-server scheduler/index react/jsx-runtime react/jsx-dev-runtime react-server-dom-webpack",
     "check-release-dependencies": "node ./scripts/release/check-release-dependencies",
     "generate-inline-fizz-runtime": "node ./scripts/rollup/generate-inline-fizz-runtime.js",
+    "generate-changelog": "node ./scripts/tasks/generate-changelog/index.js",
     "flags": "node ./scripts/flags/flags.js"
   },
   "resolutions": {

packages/eslint-plugin-react-hooks/__tests__/ESLintRulesOfHooks-test.js

@@ -585,6 +585,29 @@ const allTests = {
       code: normalizeIndent`
         // Valid: useEffectEvent can be called in custom effect hooks configured via ESLint settings
         function MyComponent({ theme }) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          useMyEffect(() => {
+            onClick();
+          });
+          useServerEffect(() => {
+            onClick();
+          });
+        }
+      `,
+      settings: {
+        'react-hooks': {
+          additionalEffectHooks: '(useMyEffect|useServerEffect)',
+        },
+      },
+    },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Valid: useEffectEvent can be called in custom effect hooks configured via ESLint settings
+        component MyComponent(theme: any) {
           const onClick = useEffectEvent(() => {
             showNotification(theme);
           });
@@ -618,6 +641,24 @@ const allTests = {
         }
       `,
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Valid because functions created with useEffectEvent can be called in a useEffect.
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          useEffect(() => {
+            onClick();
+          });
+          React.useEffect(() => {
+            onClick();
+          });
+        }
+      `,
+    },
     {
       code: normalizeIndent`
         // Valid because functions created with useEffectEvent can be passed by reference in useEffect
@@ -644,6 +685,34 @@ const allTests = {
         }
       `,
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Valid because functions created with useEffectEvent can be passed by reference in useEffect
+        // and useEffectEvent.
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          const onClick2 = useEffectEvent(() => {
+            debounce(onClick);
+            debounce(() => onClick());
+            debounce(() => { onClick() });
+            deboucne(() => debounce(onClick));
+          });
+          useEffect(() => {
+            let id = setInterval(() => onClick(), 100);
+            return () => clearInterval(onClick);
+          }, []);
+          React.useEffect(() => {
+            let id = setInterval(() => onClick(), 100);
+            return () => clearInterval(onClick);
+          }, []);
+          return null;
+        }
+      `,
+    },
     {
       code: normalizeIndent`
         function MyComponent({ theme }) {
@@ -656,6 +725,20 @@ const allTests = {
         }
       `,
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        component MyComponent(theme: any) {
+          useEffect(() => {
+            onClick();
+          });
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+        }
+      `,
+    },
     {
       code: normalizeIndent`
         function MyComponent({ theme }) {
@@ -673,6 +756,25 @@ const allTests = {
         }
       `,
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        component MyComponent(theme: any) {
+          // Can receive arguments
+          const onEvent = useEffectEvent((text) => {
+            console.log(text);
+          });
+
+          useEffect(() => {
+            onEvent('Hello world');
+          });
+          React.useEffect(() => {
+            onEvent('Hello world');
+          });
+        }
+      `,
+    },
     {
       code: normalizeIndent`
         // Valid because functions created with useEffectEvent can be called in useLayoutEffect.
@@ -689,6 +791,24 @@ const allTests = {
         }
       `,
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Valid because functions created with useEffectEvent can be called in useLayoutEffect.
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          useLayoutEffect(() => {
+            onClick();
+          });
+          React.useLayoutEffect(() => {
+            onClick();
+          });
+        }
+      `,
+    },
     {
       code: normalizeIndent`
         // Valid because functions created with useEffectEvent can be called in useInsertionEffect.
@@ -705,6 +825,24 @@ const allTests = {
         }
       `,
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Valid because functions created with useEffectEvent can be called in useInsertionEffect.
+        component MyComponent(theme) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          useInsertionEffect(() => {
+            onClick();
+          });
+          React.useInsertionEffect(() => {
+            onClick();
+          });
+        }
+      `,
+    },
     {
       code: normalizeIndent`
         // Valid because functions created with useEffectEvent can be passed by reference in useLayoutEffect 
@@ -739,6 +877,42 @@ const allTests = {
         }
       `,
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Valid because functions created with useEffectEvent can be passed by reference in useLayoutEffect.
+        // and useInsertionEffect.
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          const onClick2 = useEffectEvent(() => {
+            debounce(onClick);
+            debounce(() => onClick());
+            debounce(() => { onClick() });
+            deboucne(() => debounce(onClick));
+          });
+          useLayoutEffect(() => {
+            let id = setInterval(() => onClick(), 100);
+            return () => clearInterval(onClick);
+          }, []);
+          React.useLayoutEffect(() => {
+            let id = setInterval(() => onClick(), 100);
+            return () => clearInterval(onClick);
+          }, []);
+          useInsertionEffect(() => {
+            let id = setInterval(() => onClick(), 100);
+            return () => clearInterval(onClick);
+          }, []);
+          React.useInsertionEffect(() => {
+            let id = setInterval(() => onClick(), 100);
+            return () => clearInterval(onClick);
+          }, []);
+          return null;
+        }
+      `,
+    },
   ],
   invalid: [
     {
@@ -1525,6 +1699,22 @@ const allTests = {
       `,
       errors: [useEffectEventError('onClick', true)],
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+      // Component syntax version
+      // Invalid: useEffectEvent should not be callable in regular custom hooks without additional configuration
+      component MyComponent() {
+        const onClick = useEffectEvent(() => {
+          showNotification(theme);
+        });
+        useCustomHook(() => {
+          onClick();
+        });
+      }
+      `,
+      errors: [useEffectEventError('onClick', true)],
+    },
     {
       code: normalizeIndent`
         // Invalid: useEffectEvent should not be callable in hooks not matching the settings regex
@@ -1544,6 +1734,27 @@ const allTests = {
       },
       errors: [useEffectEventError('onClick', true)],
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Invalid: useEffectEvent should not be callable in hooks not matching the settings regex
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          useWrongHook(() => {
+            onClick();
+          });
+        }
+      `,
+      settings: {
+        'react-hooks': {
+          additionalEffectHooks: 'useMyEffect',
+        },
+      },
+      errors: [useEffectEventError('onClick', true)],
+    },
     {
       code: normalizeIndent`
         function MyComponent({ theme }) {
@@ -1555,6 +1766,19 @@ const allTests = {
       `,
       errors: [useEffectEventError('onClick', false)],
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          return <Child onClick={onClick}></Child>;
+        }
+      `,
+      errors: [useEffectEventError('onClick', false)],
+    },
     {
       code: normalizeIndent`
         // Invalid because useEffectEvent is being passed down
@@ -1566,6 +1790,19 @@ const allTests = {
       `,
       errors: [{...useEffectEventError(null, false), line: 4}],
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Invalid because useEffectEvent is being passed down
+        component MyComponent(theme: any) {
+          return <Child onClick={useEffectEvent(() => {
+            showNotification(theme);
+          })} />;
+        }
+      `,
+      errors: [{...useEffectEventError(null, false), line: 5}],
+    },
     {
       code: normalizeIndent`
         // This should error even though it shares an identifier name with the below
@@ -1601,6 +1838,43 @@ const allTests = {
         {...useEffectEventError('onClick', true), line: 15},
       ],
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // This should error even though it shares an identifier name with the below
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme)
+          });
+          return <Child onClick={onClick} />
+        }
+
+        // The useEffectEvent function shares an identifier name with the above
+        component MyOtherComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme)
+          });
+          return <Child onClick={() => onClick()} />
+        }
+
+        // The useEffectEvent function shares an identifier name with the above
+        component MyLastComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme)
+          });
+          useEffect(() => {
+            onClick(); // No error here, errors on all other uses
+            onClick;
+          })
+          return <Child />
+        }
+      `,
+      errors: [
+        {...useEffectEventError('onClick', false), line: 8},
+        {...useEffectEventError('onClick', true), line: 16},
+      ],
+    },
     {
       code: normalizeIndent`
         const MyComponent = ({ theme }) => {
@@ -1625,6 +1899,21 @@ const allTests = {
       `,
       errors: [{...useEffectEventError('onClick', false), line: 7}],
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Invalid because onClick is being aliased to foo but not invoked
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          let foo = onClick;
+          return <Bar onClick={foo} />
+        }
+      `,
+      errors: [{...useEffectEventError('onClick', false), line: 8}],
+    },
     {
       code: normalizeIndent`
         // Should error because it's being passed down to JSX, although it's been referenced once
@@ -1641,6 +1930,24 @@ const allTests = {
       `,
       errors: [useEffectEventError('onClick', false)],
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Component syntax version
+        // Should error because it's being passed down to JSX, although it's been referenced once
+        // in an effect
+        component MyComponent(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(them);
+          });
+          useEffect(() => {
+            setTimeout(onClick, 100);
+          });
+          return <Child onClick={onClick} />
+        }
+      `,
+      errors: [useEffectEventError('onClick', false)],
+    },
     {
       code: normalizeIndent`
         // Invalid because functions created with useEffectEvent cannot be called in arbitrary closures.
@@ -1676,6 +1983,43 @@ const allTests = {
           `It cannot be assigned to a variable or passed down.`,
       ],
     },
+    {
+      syntax: 'flow',
+      code: normalizeIndent`
+        // Hook syntax version
+        // Invalid because functions created with useEffectEvent cannot be called in arbitrary closures.
+        hook useMyHook(theme: any) {
+          const onClick = useEffectEvent(() => {
+            showNotification(theme);
+          });
+          // error message 1
+          const onClick2 = () => { onClick() };
+          // error message 2
+          const onClick3 = useCallback(() => onClick(), []);
+          // error message 3
+          const onClick4 = onClick;
+          return <>
+            {/** error message 4 */}
+            <Child onClick={onClick}></Child>
+            <Child onClick={onClick2}></Child>
+            <Child onClick={onClick3}></Child>
+          </>;
+        }
+      `,
+      // Explicitly test error messages here for various cases
+      errors: [
+        `\`onClick\` is a function created with React Hook "useEffectEvent", and can only be called from ` +
+          'Effects and Effect Events in the same component.',
+        `\`onClick\` is a function created with React Hook "useEffectEvent", and can only be called from ` +
+          'Effects and Effect Events in the same component.',
+        `\`onClick\` is a function created with React Hook "useEffectEvent", and can only be called from ` +
+          `Effects and Effect Events in the same component. ` +
+          `It cannot be assigned to a variable or passed down.`,
+        `\`onClick\` is a function created with React Hook "useEffectEvent", and can only be called from ` +
+          `Effects and Effect Events in the same component. ` +
+          `It cannot be assigned to a variable or passed down.`,
+      ],
+    },
   ],
 };
 

packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts

@@ -833,6 +833,18 @@ const rule = {
           recordAllUseEffectEventFunctions(getScope(node));
         }
       },
+
+      // @ts-expect-error parser-hermes produces these node types
+      ComponentDeclaration(node) {
+        // component MyComponent() { const onClick = useEffectEvent(...) }
+        recordAllUseEffectEventFunctions(getScope(node));
+      },
+
+      // @ts-expect-error parser-hermes produces these node types
+      HookDeclaration(node) {
+        // hook useMyHook() { const onClick = useEffectEvent(...) }
+        recordAllUseEffectEventFunctions(getScope(node));
+      },
     };
   },
 } satisfies Rule.RuleModule;

packages/react-client/src/ReactFlightClient.js

@@ -39,12 +39,9 @@ import type {
   EncodeFormActionCallback,
 } from './ReactFlightReplyClient';
 
-import type {Postpone} from 'react/src/ReactPostpone';
-
 import type {TemporaryReferenceSet} from './ReactFlightTemporaryReferences';
 
 import {
-  enablePostpone,
   enableProfilerTimer,
   enableComponentPerformanceTrack,
   enableAsyncDebugInfo,
@@ -89,7 +86,6 @@ import {
 import {
   REACT_LAZY_TYPE,
   REACT_ELEMENT_TYPE,
-  REACT_POSTPONE_TYPE,
   ASYNC_ITERATOR,
   REACT_FRAGMENT_TYPE,
 } from 'shared/ReactSymbols';
@@ -367,6 +363,7 @@ type Response = {
   _debugRootStack?: null | Error, // DEV-only
   _debugRootTask?: null | ConsoleTask, // DEV-only
   _debugStartTime: number, // DEV-only
+  _debugEndTime?: number, // DEV-only
   _debugIOStarted: boolean, // DEV-only
   _debugFindSourceMapURL?: void | FindSourceMapURLCallback, // DEV-only
   _debugChannel?: void | DebugChannel, // DEV-only
@@ -500,6 +497,33 @@ function createErrorChunk<T>(
   return new ReactPromise(ERRORED, null, error);
 }
 
+function filterDebugInfo(
+  response: Response,
+  value: {_debugInfo: ReactDebugInfo, ...},
+) {
+  if (response._debugEndTime === null) {
+    // No end time was defined, so we keep all debug info entries.
+    return;
+  }
+
+  // Remove any debug info entries after the defined end time. For async info
+  // that means we're including anything that was awaited before the end time,
+  // but it doesn't need to be resolved before the end time.
+  const relativeEndTime =
+    response._debugEndTime -
+    // $FlowFixMe[prop-missing]
+    performance.timeOrigin;
+  const debugInfo = [];
+  for (let i = 0; i < value._debugInfo.length; i++) {
+    const info = value._debugInfo[i];
+    if (typeof info.time === 'number' && info.time > relativeEndTime) {
+      break;
+    }
+    debugInfo.push(info);
+  }
+  value._debugInfo = debugInfo;
+}
+
 function moveDebugInfoFromChunkToInnerValue<T>(
   chunk: InitializedChunk<T> | InitializedStreamChunk<any>,
   value: T,
@@ -534,7 +558,17 @@ function moveDebugInfoFromChunkToInnerValue<T>(
   }
 }
 
+function processChunkDebugInfo<T>(
+  response: Response,
+  chunk: InitializedChunk<T> | InitializedStreamChunk<any>,
+  value: T,
+): void {
+  filterDebugInfo(response, chunk);
+  moveDebugInfoFromChunkToInnerValue(chunk, value);
+}
+
 function wakeChunk<T>(
+  response: Response,
   listeners: Array<InitializationReference | (T => mixed)>,
   value: T,
   chunk: InitializedChunk<T>,
@@ -544,16 +578,17 @@ function wakeChunk<T>(
     if (typeof listener === 'function') {
       listener(value);
     } else {
-      fulfillReference(listener, value, chunk);
+      fulfillReference(response, listener, value, chunk);
     }
   }
 
   if (__DEV__) {
-    moveDebugInfoFromChunkToInnerValue(chunk, value);
+    processChunkDebugInfo(response, chunk, value);
   }
 }
 
 function rejectChunk(
+  response: Response,
   listeners: Array<InitializationReference | (mixed => mixed)>,
   error: mixed,
 ): void {
@@ -562,7 +597,7 @@ function rejectChunk(
     if (typeof listener === 'function') {
       listener(error);
     } else {
-      rejectReference(listener, error);
+      rejectReference(response, listener.handler, error);
     }
   }
 }
@@ -595,13 +630,14 @@ function resolveBlockedCycle<T>(
 }
 
 function wakeChunkIfInitialized<T>(
+  response: Response,
   chunk: SomeChunk<T>,
   resolveListeners: Array<InitializationReference | (T => mixed)>,
   rejectListeners: null | Array<InitializationReference | (mixed => mixed)>,
 ): void {
   switch (chunk.status) {
     case INITIALIZED:
-      wakeChunk(resolveListeners, chunk.value, chunk);
+      wakeChunk(response, resolveListeners, chunk.value, chunk);
       break;
     case BLOCKED:
       // It is possible that we're blocked on our own chunk if it's a cycle.
@@ -615,7 +651,7 @@ function wakeChunkIfInitialized<T>(
           if (cyclicHandler !== null) {
             // This reference points back to this chunk. We can resolve the cycle by
             // using the value from that handler.
-            fulfillReference(reference, cyclicHandler.value, chunk);
+            fulfillReference(response, reference, cyclicHandler.value, chunk);
             resolveListeners.splice(i, 1);
             i--;
             if (rejectListeners !== null) {
@@ -624,6 +660,23 @@ function wakeChunkIfInitialized<T>(
                 rejectListeners.splice(rejectionIdx, 1);
               }
             }
+            // The status might have changed after fulfilling the reference.
+            switch ((chunk: SomeChunk<T>).status) {
+              case INITIALIZED:
+                const initializedChunk: InitializedChunk<T> = (chunk: any);
+                wakeChunk(
+                  response,
+                  resolveListeners,
+                  initializedChunk.value,
+                  initializedChunk,
+                );
+                return;
+              case ERRORED:
+                if (rejectListeners !== null) {
+                  rejectChunk(response, rejectListeners, chunk.reason);
+                }
+                return;
+            }
           }
         }
       }
@@ -650,7 +703,7 @@ function wakeChunkIfInitialized<T>(
       break;
     case ERRORED:
       if (rejectListeners) {
-        rejectChunk(rejectListeners, chunk.reason);
+        rejectChunk(response, rejectListeners, chunk.reason);
       }
       break;
   }
@@ -708,7 +761,7 @@ function triggerErrorOnChunk<T>(
   erroredChunk.status = ERRORED;
   erroredChunk.reason = error;
   if (listeners !== null) {
-    rejectChunk(listeners, error);
+    rejectChunk(response, listeners, error);
   }
 }
 
@@ -760,6 +813,12 @@ function createInitializedStreamChunk<
   value: T,
   controller: FlightStreamController,
 ): InitializedChunk<T> {
+  if (__DEV__) {
+    // Retain a strong reference to the Response while we wait for chunks.
+    if (response._pendingChunks++ === 0) {
+      response._weakResponse.response = response;
+    }
+  }
   // We use the reason field to stash the controller since we already have that
   // field. It's a bit of a hack but efficient.
   // $FlowFixMe[invalid-constructor] Flow doesn't support functions as constructors
@@ -816,7 +875,7 @@ function resolveModelChunk<T>(
     // longer be rendered or might not be the highest pri.
     initializeModelChunk(resolvedChunk);
     // The status might have changed after initialization.
-    wakeChunkIfInitialized(chunk, resolveListeners, rejectListeners);
+    wakeChunkIfInitialized(response, chunk, resolveListeners, rejectListeners);
   }
 }
 
@@ -845,12 +904,11 @@ function resolveModuleChunk<T>(
   }
   if (resolveListeners !== null) {
     initializeModuleChunk(resolvedChunk);
-    wakeChunkIfInitialized(chunk, resolveListeners, rejectListeners);
+    wakeChunkIfInitialized(response, chunk, resolveListeners, rejectListeners);
   }
 }
 
 type InitializationReference = {
-  response: Response, // TODO: Remove Response from here and pass it through instead.
   handler: InitializationHandler,
   parentObject: Object,
   key: string,
@@ -989,7 +1047,7 @@ function initializeModelChunk<T>(chunk: ResolvedModelChunk<T>): void {
         if (typeof listener === 'function') {
           listener(value);
         } else {
-          fulfillReference(listener, value, cyclicChunk);
+          fulfillReference(response, listener, value, cyclicChunk);
         }
       }
     }
@@ -1010,7 +1068,7 @@ function initializeModelChunk<T>(chunk: ResolvedModelChunk<T>): void {
     initializedChunk.value = value;
 
     if (__DEV__) {
-      moveDebugInfoFromChunkToInnerValue(initializedChunk, value);
+      processChunkDebugInfo(response, initializedChunk, value);
     }
   } catch (error) {
     const erroredChunk: ErroredChunk<T> = (chunk: any);
@@ -1397,11 +1455,12 @@ function getChunk(response: Response, id: number): SomeChunk<any> {
 }
 
 function fulfillReference(
+  response: Response,
   reference: InitializationReference,
   value: any,
   fulfilledChunk: SomeChunk<any>,
 ): void {
-  const {response, handler, parentObject, key, map, path} = reference;
+  const {handler, parentObject, key, map, path} = reference;
 
   for (let i = 1; i < path.length; i++) {
     while (
@@ -1471,7 +1530,11 @@ function fulfillReference(
             return;
           }
           default: {
-            rejectReference(reference, referencedChunk.reason);
+            rejectReference(
+              response,
+              reference.handler,
+              referencedChunk.reason,
+            );
             return;
           }
         }
@@ -1569,21 +1632,20 @@ function fulfillReference(
     initializedChunk.value = handler.value;
     initializedChunk.reason = handler.reason; // Used by streaming chunks
     if (resolveListeners !== null) {
-      wakeChunk(resolveListeners, handler.value, initializedChunk);
+      wakeChunk(response, resolveListeners, handler.value, initializedChunk);
     } else {
       if (__DEV__) {
-        moveDebugInfoFromChunkToInnerValue(initializedChunk, handler.value);
+        processChunkDebugInfo(response, initializedChunk, handler.value);
       }
     }
   }
 }
 
 function rejectReference(
-  reference: InitializationReference,
+  response: Response,
+  handler: InitializationHandler,
   error: mixed,
 ): void {
-  const {handler, response} = reference;
-
   if (handler.errored) {
     // We've already errored. We could instead build up an AggregateError
     // but if there are multiple errors we just take the first one like
@@ -1674,7 +1736,6 @@ function waitForReference<T>(
   }
 
   const reference: InitializationReference = {
-    response,
     handler,
     parentObject,
     key,
@@ -1822,10 +1883,10 @@ function loadServerReference<A: Iterable<any>, T>(
       initializedChunk.status = INITIALIZED;
       initializedChunk.value = handler.value;
       if (resolveListeners !== null) {
-        wakeChunk(resolveListeners, handler.value, initializedChunk);
+        wakeChunk(response, resolveListeners, handler.value, initializedChunk);
       } else {
         if (__DEV__) {
-          moveDebugInfoFromChunkToInnerValue(initializedChunk, handler.value);
+          processChunkDebugInfo(response, initializedChunk, handler.value);
         }
       }
     }
@@ -2562,6 +2623,7 @@ function ResponseInstance(
   replayConsole: boolean, // DEV-only
   environmentName: void | string, // DEV-only
   debugStartTime: void | number, // DEV-only
+  debugEndTime: void | number, // DEV-only
   debugChannel: void | DebugChannel, // DEV-only
 ) {
   const chunks: Map<number, SomeChunk<any>> = new Map();
@@ -2629,6 +2691,7 @@ function ResponseInstance(
       // and is not considered I/O required to load the stream.
       setTimeout(markIOStarted.bind(this), 0);
     }
+    this._debugEndTime = debugEndTime == null ? null : debugEndTime;
     this._debugFindSourceMapURL = findSourceMapURL;
     this._debugChannel = debugChannel;
     this._blockedConsole = null;
@@ -2672,6 +2735,7 @@ export function createResponse(
   replayConsole: boolean, // DEV-only
   environmentName: void | string, // DEV-only
   debugStartTime: void | number, // DEV-only
+  debugEndTime: void | number, // DEV-only
   debugChannel: void | DebugChannel, // DEV-only
 ): WeakResponse {
   return getWeakResponse(
@@ -2688,6 +2752,7 @@ export function createResponse(
       replayConsole,
       environmentName,
       debugStartTime,
+      debugEndTime,
       debugChannel,
     ),
   );
@@ -3016,7 +3081,6 @@ function resolveStream<T: ReadableStream | $AsyncIterable<any, any, void>>(
     // We already resolved. We didn't expect to see this.
     return;
   }
-  releasePendingChunk(response, chunk);
 
   const resolveListeners = chunk.value;
 
@@ -3059,10 +3123,10 @@ function resolveStream<T: ReadableStream | $AsyncIterable<any, any, void>>(
   resolvedChunk.value = stream;
   resolvedChunk.reason = controller;
   if (resolveListeners !== null) {
-    wakeChunk(resolveListeners, chunk.value, (chunk: any));
+    wakeChunk(response, resolveListeners, chunk.value, (chunk: any));
   } else {
     if (__DEV__) {
-      moveDebugInfoFromChunkToInnerValue(resolvedChunk, stream);
+      processChunkDebugInfo(response, resolvedChunk, stream);
     }
   }
 }
@@ -3202,7 +3266,12 @@ function startAsyncIterable<T>(
         initializedChunk.status = INITIALIZED;
         initializedChunk.value = {done: false, value: value};
         if (resolveListeners !== null) {
-          wakeChunkIfInitialized(chunk, resolveListeners, rejectListeners);
+          wakeChunkIfInitialized(
+            response,
+            chunk,
+            resolveListeners,
+            rejectListeners,
+          );
         }
       }
       nextWriteIndex++;
@@ -3311,6 +3380,14 @@ function stopStream(
     // We didn't expect not to have an existing stream;
     return;
   }
+  if (__DEV__) {
+    if (--response._pendingChunks === 0) {
+      // We're no longer waiting for any more chunks. We can release the strong
+      // reference to the response. We'll regain it if we ask for any more data
+      // later on.
+      response._weakResponse.response = null;
+    }
+  }
   const streamChunk: InitializedStreamChunk<any> = (chunk: any);
   const controller = streamChunk.reason;
   controller.close(row === '' ? '"$undefined"' : row);
@@ -3392,88 +3469,6 @@ function resolveErrorDev(
   return error;
 }
 
-function resolvePostponeProd(
-  response: Response,
-  id: number,
-  streamState: StreamState,
-): void {
-  if (__DEV__) {
-    // These errors should never make it into a build so we don't need to encode them in codes.json
-    // eslint-disable-next-line react-internal/prod-error-codes
-    throw new Error(
-      'resolvePostponeProd should never be called in development mode. Use resolvePostponeDev instead. This is a bug in React.',
-    );
-  }
-  const error = new Error(
-    'A Server Component was postponed. The reason is omitted in production' +
-      ' builds to avoid leaking sensitive details.',
-  );
-  const postponeInstance: Postpone = (error: any);
-  postponeInstance.$$typeof = REACT_POSTPONE_TYPE;
-  postponeInstance.stack = 'Error: ' + error.message;
-  const chunks = response._chunks;
-  const chunk = chunks.get(id);
-  if (!chunk) {
-    const newChunk: ErroredChunk<any> = createErrorChunk(
-      response,
-      postponeInstance,
-    );
-    chunks.set(id, newChunk);
-  } else {
-    triggerErrorOnChunk(response, chunk, postponeInstance);
-  }
-}
-
-function resolvePostponeDev(
-  response: Response,
-  id: number,
-  reason: string,
-  stack: ReactStackTrace,
-  env: string,
-  streamState: StreamState,
-): void {
-  if (!__DEV__) {
-    // These errors should never make it into a build so we don't need to encode them in codes.json
-    // eslint-disable-next-line react-internal/prod-error-codes
-    throw new Error(
-      'resolvePostponeDev should never be called in production mode. Use resolvePostponeProd instead. This is a bug in React.',
-    );
-  }
-  let postponeInstance: Postpone;
-  const callStack = buildFakeCallStack(
-    response,
-    stack,
-    env,
-    false,
-    // $FlowFixMe[incompatible-use]
-    Error.bind(null, reason || ''),
-  );
-  const rootTask = response._debugRootTask;
-  if (rootTask != null) {
-    postponeInstance = rootTask.run(callStack);
-  } else {
-    postponeInstance = callStack();
-  }
-  postponeInstance.$$typeof = REACT_POSTPONE_TYPE;
-  const chunks = response._chunks;
-  const chunk = chunks.get(id);
-  if (!chunk) {
-    const newChunk: ErroredChunk<any> = createErrorChunk(
-      response,
-      postponeInstance,
-    );
-    if (__DEV__) {
-      resolveChunkDebugInfo(response, streamState, newChunk);
-    }
-    chunks.set(id, newChunk);
-  } else {
-    if (__DEV__) {
-      resolveChunkDebugInfo(response, streamState, chunk);
-    }
-    triggerErrorOnChunk(response, chunk, postponeInstance);
-  }
-}
-
 function resolveErrorModel(
   response: Response,
   id: number,
@@ -4825,25 +4820,6 @@ function processFullStringRow(
       return;
     }
     // Fallthrough
-    case 80 /* "P" */: {
-      if (enablePostpone) {
-        if (__DEV__) {
-          const postponeInfo = JSON.parse(row);
-          resolvePostponeDev(
-            response,
-            id,
-            postponeInfo.reason,
-            postponeInfo.stack,
-            postponeInfo.env,
-            streamState,
-          );
-        } else {
-          resolvePostponeProd(response, id, streamState);
-        }
-        return;
-      }
-    }
-    // Fallthrough
     default: /* """ "{" "[" "t" "f" "n" "0" - "9" */ {
       if (__DEV__ && row === '') {
         resolveDebugHalt(response, id);
@@ -4894,6 +4870,7 @@ export function processBinaryChunk(
           resolvedRowTag === 65 /* "A" */ ||
           resolvedRowTag === 79 /* "O" */ ||
           resolvedRowTag === 111 /* "o" */ ||
+          resolvedRowTag === 98 /* "b" */ ||
           resolvedRowTag === 85 /* "U" */ ||
           resolvedRowTag === 83 /* "S" */ ||
           resolvedRowTag === 115 /* "s" */ ||
@@ -4953,14 +4930,31 @@ export function processBinaryChunk(
       // We found the last chunk of the row
       const length = lastIdx - i;
       const lastChunk = new Uint8Array(chunk.buffer, offset, length);
-      processFullBinaryRow(
-        response,
-        streamState,
-        rowID,
-        rowTag,
-        buffer,
-        lastChunk,
-      );
+
+      // Check if this is a Uint8Array for a byte stream. We enqueue it
+      // immediately but need to determine if we can use zero-copy or must copy.
+      if (rowTag === 98 /* "b" */) {
+        resolveBuffer(
+          response,
+          rowID,
+          // If we're at the end of the RSC chunk, no more parsing will access
+          // this buffer and we don't need to copy the chunk to allow detaching
+          // the buffer, otherwise we need to copy.
+          lastIdx === chunkLength ? lastChunk : lastChunk.slice(),
+          streamState,
+        );
+      } else {
+        // Process all other row types.
+        processFullBinaryRow(
+          response,
+          streamState,
+          rowID,
+          rowTag,
+          buffer,
+          lastChunk,
+        );
+      }
+
       // Reset state machine for a new row
       i = lastIdx;
       if (rowState === ROW_CHUNK_BY_NEWLINE) {
@@ -4973,14 +4967,27 @@ export function processBinaryChunk(
       rowLength = 0;
       buffer.length = 0;
     } else {
-      // The rest of this row is in a future chunk. We stash the rest of the
-      // current chunk until we can process the full row.
+      // The rest of this row is in a future chunk.
       const length = chunk.byteLength - i;
       const remainingSlice = new Uint8Array(chunk.buffer, offset, length);
-      buffer.push(remainingSlice);
-      // Update how many bytes we're still waiting for. If we're looking for
-      // a newline, this doesn't hurt since we'll just ignore it.
-      rowLength -= remainingSlice.byteLength;
+
+      // For byte streams, we can enqueue the partial row immediately without
+      // copying since we're at the end of the RSC chunk and no more parsing
+      // will access this buffer.
+      if (rowTag === 98 /* "b" */) {
+        // Update how many bytes we're still waiting for. We need to do this
+        // before enqueueing, as enqueue will detach the buffer and byteLength
+        // will become 0.
+        rowLength -= remainingSlice.byteLength;
+        resolveBuffer(response, rowID, remainingSlice, streamState);
+      } else {
+        // For other row types, stash the rest of the current chunk until we can
+        // process the full row.
+        buffer.push(remainingSlice);
+        // Update how many bytes we're still waiting for. If we're looking for
+        // a newline, this doesn't hurt since we'll just ignore it.
+        rowLength -= remainingSlice.byteLength;
+      }
       break;
     }
   }

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3884,4 +3884,19 @@ describe('ReactFlight', () => {
       </main>,
     );
   });
+
+  // @gate enableOptimisticKey
+  it('collapses optimistic keys to an optimistic key', async () => {
+    function Bar({text}) {
+      return <div />;
+    }
+    function Foo() {
+      return <Bar key={ReactServer.optimisticKey} />;
+    }
+    const transport = ReactNoopFlightServer.render({
+      element: <Foo key="Outer Key" />,
+    });
+    const model = await ReactNoopFlightClient.read(transport);
+    expect(model.element.key).toBe(React.optimisticKey);
+  });
 });

packages/react-devtools-shared/src/__tests__/bridge-test.js

@@ -27,7 +27,7 @@ describe('Bridge', () => {
     // Check that we're wired up correctly.
     bridge.send('reloadAppForProfiling');
     jest.runAllTimers();
-    expect(wall.send).toHaveBeenCalledWith('reloadAppForProfiling');
+    expect(wall.send).toHaveBeenCalledWith('reloadAppForProfiling', undefined);
 
     // Should flush pending messages and then shut down.
     wall.send.mockClear();
@@ -37,7 +37,7 @@ describe('Bridge', () => {
     jest.runAllTimers();
     expect(wall.send).toHaveBeenCalledWith('update', '1');
     expect(wall.send).toHaveBeenCalledWith('update', '2');
-    expect(wall.send).toHaveBeenCalledWith('shutdown');
+    expect(wall.send).toHaveBeenCalledWith('shutdown', undefined);
     expect(shutdownCallback).toHaveBeenCalledTimes(1);
 
     // Verify that the Bridge doesn't send messages after shutdown.

packages/react-devtools-shared/src/__tests__/setupTests.js

@@ -116,6 +116,16 @@ function shouldIgnoreConsoleErrorOrWarn(args) {
     return false;
   }
 
+  const maybeError = args[1];
+  if (
+    maybeError !== null &&
+    typeof maybeError === 'object' &&
+    maybeError.message === 'Simulated error coming from DevTools'
+  ) {
+    // Error from forcing an error boundary.
+    return true;
+  }
+
   return global._ignoredErrorOrWarningMessages.some(errorOrWarningMessage => {
     return firstArg.indexOf(errorOrWarningMessage) !== -1;
   });

packages/react-devtools-shared/src/__tests__/store-test.js

@@ -3283,8 +3283,6 @@ describe('Store', () => {
         <Suspense name="Outer" rects={null}>
     `);
 
-    console.log('...........................');
-
     await actAsync(() => {
       resolve('loaded');
     });
@@ -3300,4 +3298,100 @@ describe('Store', () => {
           <Suspense name="Inner" rects={[{x:1,y:2,width:6,height:1}]}>
     `);
   });
+
+  // @reactVersion >= 19.0
+  it('measures rects when reconnecting', async () => {
+    function Component({children, promise}) {
+      let content = '';
+      if (promise) {
+        const value = readValue(promise);
+        if (typeof value === 'string') {
+          content += value;
+        }
+      }
+      return (
+        <div>
+          {content}
+          {children}
+        </div>
+      );
+    }
+
+    function App({outer, inner}) {
+      return (
+        <React.Suspense
+          name="outer"
+          fallback={<Component key="outer-fallback">loading outer</Component>}>
+          <Component key="outer-content" promise={outer}>
+            outer content
+          </Component>
+          <React.Suspense
+            name="inner"
+            fallback={
+              <Component key="inner-fallback">loading inner</Component>
+            }>
+            <Component key="inner-content" promise={inner}>
+              inner content
+            </Component>
+          </React.Suspense>
+        </React.Suspense>
+      );
+    }
+
+    await actAsync(() => {
+      render(<App outer={null} inner={null} />);
+    });
+
+    expect(store).toMatchInlineSnapshot(`
+      [root]
+        ▾ <App>
+          ▾ <Suspense name="outer">
+              <Component key="outer-content">
+            ▾ <Suspense name="inner">
+                <Component key="inner-content">
+      [suspense-root]  rects={[{x:1,y:2,width:13,height:1}, {x:1,y:2,width:13,height:1}]}
+        <Suspense name="outer" rects={[{x:1,y:2,width:13,height:1}, {x:1,y:2,width:13,height:1}]}>
+          <Suspense name="inner" rects={[{x:1,y:2,width:13,height:1}]}>
+    `);
+
+    let outerResolve;
+    const outerPromise = new Promise(resolve => {
+      outerResolve = resolve;
+    });
+
+    let innerResolve;
+    const innerPromise = new Promise(resolve => {
+      innerResolve = resolve;
+    });
+    await actAsync(() => {
+      render(<App outer={outerPromise} inner={innerPromise} />);
+    });
+
+    expect(store).toMatchInlineSnapshot(`
+      [root]
+        ▾ <App>
+          ▾ <Suspense name="outer">
+              <Component key="outer-fallback">
+      [suspense-root]  rects={[{x:1,y:2,width:13,height:1}, {x:1,y:2,width:13,height:1}, {x:1,y:2,width:13,height:1}]}
+        <Suspense name="outer" rects={[{x:1,y:2,width:13,height:1}, {x:1,y:2,width:13,height:1}]}>
+          <Suspense name="inner" rects={[{x:1,y:2,width:13,height:1}]}>
+    `);
+
+    await actAsync(() => {
+      outerResolve('..');
+      innerResolve('.');
+    });
+
+    expect(store).toMatchInlineSnapshot(`
+      [root]
+        ▾ <App>
+          ▾ <Suspense name="outer">
+              <Component key="outer-content">
+            ▾ <Suspense name="inner">
+                <Component key="inner-content">
+      [suspense-root]  rects={[{x:1,y:2,width:15,height:1}, {x:1,y:2,width:14,height:1}]}
+        <Suspense name="outer" rects={[{x:1,y:2,width:15,height:1}, {x:1,y:2,width:14,height:1}]}>
+          <Suspense name="inner" rects={[{x:1,y:2,width:14,height:1}]}>
+    `);
+  });
 });