[compiler] InferEffects uses effects as value keys

In InferReferenceEffects we used `InstructionValue` as the key to represent values, since each time we process an instruction this object will be the same. However this was always a bit of a hack, and in the new model and InferMutationAliasingEffects we can instead use the (creation) effect as the stable value. This avoids an extra layer of memoization since the effects are already interned anyway.

.codesandbox/ci.json

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

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

@@ -36,14 +36,6 @@ export enum ErrorSeverity {
    * memoization.
    */
   CannotPreserveMemoization = 'CannotPreserveMemoization',
-  /**
-   * An API that is known to be incompatible with the compiler. Generally as a result of
-   * the library using "interior mutability", ie having a value whose referential identity
-   * stays the same but which provides access to values that can change. For example a
-   * function that doesn't change but returns different results, or an object that doesn't
-   * change identity but whose properties change.
-   */
-  IncompatibleLibrary = 'IncompatibleLibrary',
   /**
    * Unhandled syntax that we don't support yet.
    */
@@ -466,8 +458,7 @@ export class CompilerError extends Error {
         case ErrorSeverity.InvalidJS:
         case ErrorSeverity.InvalidReact:
         case ErrorSeverity.InvalidConfig:
-        case ErrorSeverity.UnsupportedJS:
-        case ErrorSeverity.IncompatibleLibrary: {
+        case ErrorSeverity.UnsupportedJS: {
           return true;
         }
         case ErrorSeverity.CannotPreserveMemoization:
@@ -515,9 +506,8 @@ function printErrorSummary(severity: ErrorSeverity, message: string): string {
       severityCategory = 'Error';
       break;
     }
-    case ErrorSeverity.IncompatibleLibrary:
     case ErrorSeverity.CannotPreserveMemoization: {
-      severityCategory = 'Compilation Skipped';
+      severityCategory = 'Memoization';
       break;
     }
     case ErrorSeverity.Invariant: {
@@ -557,9 +547,6 @@ export enum ErrorCategory {
   // Checks that manual memoization is preserved
   PreserveManualMemo = 'PreserveManualMemo',
 
-  // Checks for known incompatible libraries
-  IncompatibleLibrary = 'IncompatibleLibrary',
-
   // Checking for no mutations of props, hook arguments, hook return values
   Immutability = 'Immutability',
 
@@ -883,15 +870,6 @@ function getRuleForCategoryImpl(category: ErrorCategory): LintRule {
         recommended: true,
       };
     }
-    case ErrorCategory.IncompatibleLibrary: {
-      return {
-        category,
-        name: 'incompatible-library',
-        description:
-          'Validates against usage of libraries which are incompatible with memoization (manual or automatic)',
-        recommended: true,
-      };
-    }
     default: {
       assertExhaustive(category, `Unsupported category ${category}`);
     }

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

@@ -1,91 +0,0 @@
-/**
- * Copyright (c) Meta Platforms, Inc. and affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-import {Effect, ValueKind} from '..';
-import {TypeConfig} from './TypeSchema';
-
-/**
- * Libraries developed before we officially documented the [Rules of React](https://react.dev/reference/rules)
- * implement APIs which cannot be memoized safely, either via manual or automatic memoization.
- *
- * Any non-hook API that is designed to be called during render (not events/effects) should be safe to memoize:
- *
- * ```js
- * function Component() {
- *   const {someFunction} = useLibrary();
- *   // it should always be safe to memoize functions like this
- *  const result = useMemo(() => someFunction(), [someFunction]);
- * }
- * ```
- *
- * However, some APIs implement "interior mutability" — mutating values rather than copying into a new value
- * and setting state with the new value. Such functions (`someFunction()` in the example) could return different
- * values even though the function itself is the same object. This breaks memoization, since React relies on
- * the outer object (or function) changing if part of its value has changed.
- *
- * Given that we didn't have the Rules of React precisely documented prior to the introduction of React compiler,
- * it's understandable that some libraries accidentally shipped APIs that break this rule. However, developers
- * can easily run into pitfalls with these APIs. They may manually memoize them, which can break their app. Or
- * they may try using React Compiler, and think that the compiler has broken their code.
- *
- * To help ensure that developers can successfully use the compiler with existing code, this file teaches the
- * compiler about specific APIs that are known to be incompatible with memoization. We've tried to be as precise
- * as possible.
- *
- * The React team is open to collaborating with library authors to help develop compatible versions of these APIs,
- * and we have already reached out to the teams who own any API listed here to ensure they are aware of the issue.
- */
-export function defaultModuleTypeProvider(
-  moduleName: string,
-): TypeConfig | null {
-  switch (moduleName) {
-    case 'react-hook-form': {
-      return {
-        kind: 'object',
-        properties: {
-          useForm: {
-            kind: 'hook',
-            returnType: {
-              kind: 'object',
-              properties: {
-                // Only the `watch()` function returned by react-hook-form's `useForm()` API is incompatible
-                watch: {
-                  kind: 'function',
-                  positionalParams: [],
-                  restParam: Effect.Read,
-                  calleeEffect: Effect.Read,
-                  returnType: {kind: 'type', name: 'Any'},
-                  returnValueKind: ValueKind.Mutable,
-                  knownIncompatible: `React Hook Form's \`useForm()\` API returns a \`watch()\` function which cannot be memoized safely.`,
-                },
-              },
-            },
-          },
-        },
-      };
-    }
-    case '@tanstack/react-table': {
-      return {
-        kind: 'object',
-        properties: {
-          /*
-           * Many of the properties of `useReactTable()`'s return value are incompatible, so we mark the entire hook
-           * as incompatible
-           */
-          useReactTable: {
-            kind: 'hook',
-            positionalParams: [],
-            restParam: Effect.Read,
-            returnType: {kind: 'type', name: 'Any'},
-            knownIncompatible: `TanStack Table's \`useReactTable()\` API returns functions that cannot be memoized safely`,
-          },
-        },
-      };
-    }
-  }
-  return null;
-}

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

@@ -50,7 +50,6 @@ import {
 import {Scope as BabelScope, NodePath} from '@babel/traverse';
 import {TypeSchema} from './TypeSchema';
 import {FlowTypeEnv} from '../Flood/Types';
-import {defaultModuleTypeProvider} from './DefaultModuleTypeProvider';
 
 export const ReactElementSymbolSchema = z.object({
   elementSymbol: z.union([
@@ -861,16 +860,10 @@ export class Environment {
   #resolveModuleType(moduleName: string, loc: SourceLocation): Global | null {
     let moduleType = this.#moduleTypes.get(moduleName);
     if (moduleType === undefined) {
-      /*
-       * NOTE: Zod doesn't work when specifying a function as a default, so we have to
-       * fallback to the default value here
-       */
-      const moduleTypeProvider =
-        this.config.moduleTypeProvider ?? defaultModuleTypeProvider;
-      if (moduleTypeProvider == null) {
+      if (this.config.moduleTypeProvider == null) {
         return null;
       }
-      const unparsedModuleConfig = moduleTypeProvider(moduleName);
+      const unparsedModuleConfig = this.config.moduleTypeProvider(moduleName);
       if (unparsedModuleConfig != null) {
         const parsedModuleConfig = TypeSchema.safeParse(unparsedModuleConfig);
         if (!parsedModuleConfig.success) {

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

@@ -1001,7 +1001,6 @@ export function installTypeConfig(
         mutableOnlyIfOperandsAreMutable:
           typeConfig.mutableOnlyIfOperandsAreMutable === true,
         aliasing: typeConfig.aliasing,
-        knownIncompatible: typeConfig.knownIncompatible ?? null,
       });
     }
     case 'hook': {
@@ -1020,7 +1019,6 @@ export function installTypeConfig(
         returnValueKind: typeConfig.returnValueKind ?? ValueKind.Frozen,
         noAlias: typeConfig.noAlias === true,
         aliasing: typeConfig.aliasing,
-        knownIncompatible: typeConfig.knownIncompatible ?? null,
       });
     }
     case 'object': {

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

@@ -332,7 +332,6 @@ export type FunctionSignature = {
   mutableOnlyIfOperandsAreMutable?: boolean;
 
   impure?: boolean;
-  knownIncompatible?: string | null | undefined;
 
   canonicalName?: string;
 

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

@@ -251,7 +251,6 @@ export type FunctionTypeConfig = {
   impure?: boolean | null | undefined;
   canonicalName?: string | null | undefined;
   aliasing?: AliasingSignatureConfig | null | undefined;
-  knownIncompatible?: string | null | undefined;
 };
 export const FunctionTypeSchema: z.ZodType<FunctionTypeConfig> = z.object({
   kind: z.literal('function'),
@@ -265,7 +264,6 @@ export const FunctionTypeSchema: z.ZodType<FunctionTypeConfig> = z.object({
   impure: z.boolean().nullable().optional(),
   canonicalName: z.string().nullable().optional(),
   aliasing: AliasingSignatureSchema.nullable().optional(),
-  knownIncompatible: z.string().nullable().optional(),
 });
 
 export type HookTypeConfig = {
@@ -276,7 +274,6 @@ export type HookTypeConfig = {
   returnValueKind?: ValueKind | null | undefined;
   noAlias?: boolean | null | undefined;
   aliasing?: AliasingSignatureConfig | null | undefined;
-  knownIncompatible?: string | null | undefined;
 };
 export const HookTypeSchema: z.ZodType<HookTypeConfig> = z.object({
   kind: z.literal('hook'),
@@ -286,7 +283,6 @@ export const HookTypeSchema: z.ZodType<HookTypeConfig> = z.object({
   returnValueKind: ValueKindSchema.nullable().optional(),
   noAlias: z.boolean().nullable().optional(),
   aliasing: AliasingSignatureSchema.nullable().optional(),
-  knownIncompatible: z.string().nullable().optional(),
 });
 
 export type BuiltInTypeConfig =

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

@@ -25,7 +25,6 @@ import {
   IdentifierId,
   Instruction,
   InstructionKind,
-  InstructionValue,
   isArrayType,
   isJsxType,
   isMapType,
@@ -57,7 +56,6 @@ import {
   printAliasingSignature,
   printIdentifier,
   printInstruction,
-  printInstructionValue,
   printPlace,
   printSourceLocation,
 } from '../HIR/PrintHIR';
@@ -108,11 +106,11 @@ export function inferMutationAliasingEffects(
   const statesByBlock: Map<BlockId, InferenceState> = new Map();
 
   for (const ref of fn.context) {
-    // TODO: using InstructionValue as a bit of a hack, but it's pragmatic
-    const value: InstructionValue = {
-      kind: 'ObjectExpression',
-      properties: [],
-      loc: ref.loc,
+    const value: AliasingEffect = {
+      kind: 'Create',
+      into: ref,
+      value: ValueKind.Context,
+      reason: ValueReason.Other,
     };
     initialState.initialize(value, {
       kind: ValueKind.Context,
@@ -145,10 +143,11 @@ export function inferMutationAliasingEffects(
     }
     if (ref != null) {
       const place = ref.kind === 'Identifier' ? ref : ref.place;
-      const value: InstructionValue = {
-        kind: 'ObjectExpression',
-        properties: [],
-        loc: place.loc,
+      const value: AliasingEffect = {
+        kind: 'Create',
+        into: place,
+        value: ValueKind.Mutable,
+        reason: ValueReason.Other,
       };
       initialState.initialize(value, {
         kind: ValueKind.Mutable,
@@ -265,8 +264,6 @@ function findHoistedContextDeclarations(
 class Context {
   internedEffects: Map<string, AliasingEffect> = new Map();
   instructionSignatureCache: Map<Instruction, InstructionSignature> = new Map();
-  effectInstructionValueCache: Map<AliasingEffect, InstructionValue> =
-    new Map();
   applySignatureCache: Map<
     AliasingSignature,
     Map<AliasingEffect, Array<AliasingEffect> | null>
@@ -318,10 +315,11 @@ function inferParam(
   paramKind: AbstractValue,
 ): void {
   const place = param.kind === 'Identifier' ? param : param.place;
-  const value: InstructionValue = {
-    kind: 'Primitive',
-    loc: place.loc,
-    value: undefined,
+  const value: AliasingEffect = {
+    kind: 'Create',
+    into: place,
+    value: paramKind.kind,
+    reason: ValueReason.Other,
   };
   initialState.initialize(value, paramKind);
   initialState.define(place, value);
@@ -542,20 +540,11 @@ function applyEffect(
       });
       initialized.add(effect.into.identifier.id);
 
-      let value = context.effectInstructionValueCache.get(effect);
-      if (value == null) {
-        value = {
-          kind: 'ObjectExpression',
-          properties: [],
-          loc: effect.into.loc,
-        };
-        context.effectInstructionValueCache.set(effect, value);
-      }
-      state.initialize(value, {
+      state.initialize(effect, {
         kind: effect.value,
         reason: new Set([effect.reason]),
       });
-      state.define(effect.into, value);
+      state.define(effect.into, effect);
       effects.push(effect);
       break;
     }
@@ -582,20 +571,11 @@ function applyEffect(
       initialized.add(effect.into.identifier.id);
 
       const fromValue = state.kind(effect.from);
-      let value = context.effectInstructionValueCache.get(effect);
-      if (value == null) {
-        value = {
-          kind: 'ObjectExpression',
-          properties: [],
-          loc: effect.into.loc,
-        };
-        context.effectInstructionValueCache.set(effect, value);
-      }
-      state.initialize(value, {
+      state.initialize(effect, {
         kind: fromValue.kind,
         reason: new Set(fromValue.reason),
       });
-      state.define(effect.into, value);
+      state.define(effect.into, effect);
       switch (fromValue.kind) {
         case ValueKind.Primitive:
         case ValueKind.Global: {
@@ -683,11 +663,11 @@ function applyEffect(
           operand.effect = Effect.Read;
         }
       }
-      state.initialize(effect.function, {
+      state.initialize(effect, {
         kind: isMutable ? ValueKind.Mutable : ValueKind.Frozen,
         reason: new Set([]),
       });
-      state.define(effect.into, effect.function);
+      state.define(effect.into, effect);
       for (const capture of effect.captures) {
         applyEffect(
           context,
@@ -793,38 +773,20 @@ function applyEffect(
             initialized,
             effects,
           );
-          let value = context.effectInstructionValueCache.get(effect);
-          if (value == null) {
-            value = {
-              kind: 'Primitive',
-              value: undefined,
-              loc: effect.from.loc,
-            };
-            context.effectInstructionValueCache.set(effect, value);
-          }
-          state.initialize(value, {
+          state.initialize(effect, {
             kind: fromKind,
             reason: new Set(fromValue.reason),
           });
-          state.define(effect.into, value);
+          state.define(effect.into, effect);
           break;
         }
         case ValueKind.Global:
         case ValueKind.Primitive: {
-          let value = context.effectInstructionValueCache.get(effect);
-          if (value == null) {
-            value = {
-              kind: 'Primitive',
-              value: undefined,
-              loc: effect.from.loc,
-            };
-            context.effectInstructionValueCache.set(effect, value);
-          }
-          state.initialize(value, {
+          state.initialize(effect, {
             kind: fromKind,
             reason: new Set(fromValue.reason),
           });
-          state.define(effect.into, value);
+          state.define(effect.into, effect);
           break;
         }
         default: {
@@ -839,14 +801,15 @@ function applyEffect(
       const functionValues = state.values(effect.function);
       if (
         functionValues.length === 1 &&
-        functionValues[0].kind === 'FunctionExpression' &&
-        functionValues[0].loweredFunc.func.aliasingEffects != null
+        functionValues[0].kind === 'CreateFunction' &&
+        functionValues[0].function.kind === 'FunctionExpression' &&
+        functionValues[0].function.loweredFunc.func.aliasingEffects != null
       ) {
         /*
          * We're calling a locally declared function, we already know it's effects!
          * We just have to substitute in the args for the params
          */
-        const functionExpr = functionValues[0];
+        const functionExpr = functionValues[0].function;
         let signature = context.functionSignatureCache.get(functionExpr);
         if (signature == null) {
           signature = buildSignatureFromFunctionExpression(
@@ -1136,19 +1099,19 @@ class InferenceState {
   #isFunctionExpression: boolean;
 
   // The kind of each value, based on its allocation site
-  #values: Map<InstructionValue, AbstractValue>;
+  #values: Map<AliasingEffect, AbstractValue>;
   /*
    * The set of values pointed to by each identifier. This is a set
    * to accomodate phi points (where a variable may have different
    * values from different control flow paths).
    */
-  #variables: Map<IdentifierId, Set<InstructionValue>>;
+  #variables: Map<IdentifierId, Set<AliasingEffect>>;
 
   constructor(
     env: Environment,
     isFunctionExpression: boolean,
-    values: Map<InstructionValue, AbstractValue>,
-    variables: Map<IdentifierId, Set<InstructionValue>>,
+    values: Map<AliasingEffect, AbstractValue>,
+    variables: Map<IdentifierId, Set<AliasingEffect>>,
   ) {
     this.env = env;
     this.#isFunctionExpression = isFunctionExpression;
@@ -1168,18 +1131,11 @@ class InferenceState {
   }
 
   // (Re)initializes a @param value with its default @param kind.
-  initialize(value: InstructionValue, kind: AbstractValue): void {
-    CompilerError.invariant(value.kind !== 'LoadLocal', {
-      reason:
-        '[InferMutationAliasingEffects] Expected all top-level identifiers to be defined as variables, not values',
-      description: null,
-      loc: value.loc,
-      suggestions: null,
-    });
+  initialize(value: AliasingEffect, kind: AbstractValue): void {
     this.#values.set(value, kind);
   }
 
-  values(place: Place): Array<InstructionValue> {
+  values(place: Place): Array<AliasingEffect> {
     const values = this.#variables.get(place.identifier.id);
     CompilerError.invariant(values != null, {
       reason: `[InferMutationAliasingEffects] Expected value kind to be initialized`,
@@ -1242,13 +1198,13 @@ class InferenceState {
   }
 
   // Defines (initializing or updating) a variable with a specific kind of value.
-  define(place: Place, value: InstructionValue): void {
+  define(place: Place, value: AliasingEffect): void {
     CompilerError.invariant(this.#values.has(value), {
       reason: `[InferMutationAliasingEffects] Expected value to be initialized at '${printSourceLocation(
-        value.loc,
+        place.loc,
       )}'`,
-      description: printInstructionValue(value),
-      loc: value.loc,
+      description: printAliasingEffect(value),
+      loc: place.loc,
       suggestions: null,
     });
     this.#variables.set(place.identifier.id, new Set([value]));
@@ -1288,17 +1244,17 @@ class InferenceState {
     }
   }
 
-  freezeValue(value: InstructionValue, reason: ValueReason): void {
+  freezeValue(value: AliasingEffect, reason: ValueReason): void {
     this.#values.set(value, {
       kind: ValueKind.Frozen,
       reason: new Set([reason]),
     });
     if (
-      value.kind === 'FunctionExpression' &&
+      value.kind === 'CreateFunction' &&
       (this.env.config.enablePreserveExistingMemoizationGuarantees ||
         this.env.config.enableTransitivelyFreezeFunctionExpressions)
     ) {
-      for (const place of value.loweredFunc.func.context) {
+      for (const place of value.function.loweredFunc.func.context) {
         this.freeze(place, reason);
       }
     }
@@ -1373,8 +1329,8 @@ class InferenceState {
    * termination.
    */
   merge(other: InferenceState): InferenceState | null {
-    let nextValues: Map<InstructionValue, AbstractValue> | null = null;
-    let nextVariables: Map<IdentifierId, Set<InstructionValue>> | null = null;
+    let nextValues: Map<AliasingEffect, AbstractValue> | null = null;
+    let nextVariables: Map<IdentifierId, Set<AliasingEffect>> | null = null;
 
     for (const [id, thisValue] of this.#values) {
       const otherValue = other.#values.get(id);
@@ -1398,7 +1354,7 @@ class InferenceState {
     for (const [id, thisValues] of this.#variables) {
       const otherValues = other.#variables.get(id);
       if (otherValues !== undefined) {
-        let mergedValues: Set<InstructionValue> | null = null;
+        let mergedValues: Set<AliasingEffect> | null = null;
         for (const otherValue of otherValues) {
           if (!thisValues.has(otherValue)) {
             mergedValues = mergedValues ?? new Set(thisValues);
@@ -1451,8 +1407,8 @@ class InferenceState {
    */
   debug(): any {
     const result: any = {values: {}, variables: {}};
-    const objects: Map<InstructionValue, number> = new Map();
-    function identify(value: InstructionValue): number {
+    const objects: Map<AliasingEffect, number> = new Map();
+    function identify(value: AliasingEffect): number {
       let id = objects.get(value);
       if (id == null) {
         id = objects.size;
@@ -1464,7 +1420,7 @@ class InferenceState {
       const id = identify(value);
       result.values[id] = {
         abstract: this.debugAbstractValue(kind),
-        value: printInstructionValue(value),
+        value: printAliasingEffect(value),
       };
     }
     for (const [variable, values] of this.#variables) {
@@ -1481,7 +1437,7 @@ class InferenceState {
   }
 
   inferPhi(phi: Phi): void {
-    const values: Set<InstructionValue> = new Set();
+    const values: Set<AliasingEffect> = new Set();
     for (const [_, operand] of phi.operands) {
       const operandValues = this.#variables.get(operand.identifier.id);
       // This is a backedge that will be handled later by State.merge
@@ -2170,27 +2126,6 @@ function computeEffectsForLegacySignature(
       }),
     });
   }
-  if (signature.knownIncompatible != null && state.env.isInferredMemoEnabled) {
-    const errors = new CompilerError();
-    errors.pushDiagnostic(
-      CompilerDiagnostic.create({
-        category: ErrorCategory.IncompatibleLibrary,
-        severity: ErrorSeverity.IncompatibleLibrary,
-        reason: 'Use of incompatible library',
-        description: [
-          'This API returns functions which cannot be memoized without leading to stale UI. ' +
-            'To prevent this, by default React Compiler will skip memoizing this component/hook. ' +
-            'However, you may see issues if values from this API are passed to other components/hooks that are ' +
-            'memoized.',
-        ].join(''),
-      }).withDetail({
-        kind: 'error',
-        loc: receiver.loc,
-        message: signature.knownIncompatible,
-      }),
-    );
-    throw errors;
-  }
   const stores: Array<Place> = [];
   const captures: Array<Place> = [];
   function visit(place: Place, effect: Effect): void {
@@ -2368,8 +2303,9 @@ function areArgumentsImmutableAndNonMutating(
     const values = state.values(place);
     for (const value of values) {
       if (
-        value.kind === 'FunctionExpression' &&
-        value.loweredFunc.func.params.some(param => {
+        value.kind === 'CreateFunction' &&
+        value.function.kind === 'FunctionExpression' &&
+        value.function.loweredFunc.func.params.some(param => {
           const place = param.kind === 'Identifier' ? param : param.place;
           const range = place.identifier.mutableRange;
           return range.end > range.start + 1;

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

@@ -175,41 +175,6 @@ export function alignReactiveScopesToBlockScopesHIR(fn: HIRFunction): void {
       if (node != null) {
         valueBlockNodes.set(fallthrough, node);
       }
-    } else if (terminal.kind === 'goto') {
-      /**
-       * If we encounter a goto that is not to the natural fallthrough of the current
-       * block (not the topmost fallthrough on the stack), then this is a goto to a
-       * label. Any scopes that extend beyond the goto must be extended to include
-       * the labeled range, so that the break statement doesn't accidentally jump
-       * out of the scope. We do this by extending the start and end of the scope's
-       * range to the label and its fallthrough respectively.
-       */
-      const start = activeBlockFallthroughRanges.find(
-        range => range.fallthrough === terminal.block,
-      );
-      if (start != null && start !== activeBlockFallthroughRanges.at(-1)) {
-        const fallthroughBlock = fn.body.blocks.get(start.fallthrough)!;
-        const firstId =
-          fallthroughBlock.instructions[0]?.id ?? fallthroughBlock.terminal.id;
-        for (const scope of activeScopes) {
-          /**
-           * activeScopes is only filtered at block start points, so some of the
-           * scopes may not actually be active anymore, ie we've past their end
-           * instruction. Only extend ranges for scopes that are actually active.
-           *
-           * TODO: consider pruning activeScopes per instruction
-           */
-          if (scope.range.end <= terminal.id) {
-            continue;
-          }
-          scope.range.start = makeInstructionId(
-            Math.min(start.range.start, scope.range.start),
-          );
-          scope.range.end = makeInstructionId(
-            Math.max(firstId, scope.range.end),
-          );
-        }
-      }
     }
 
     /*

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

@@ -411,9 +411,7 @@ class CollectDependenciesVisitor extends ReactiveFunctionVisitor<
     this.state = state;
     this.options = {
       memoizeJsxElements: !this.env.config.enableForest,
-      forceMemoizePrimitives:
-        this.env.config.enableForest ||
-        this.env.config.enablePreserveExistingMemoizationGuarantees,
+      forceMemoizePrimitives: this.env.config.enableForest,
     };
   }
 
@@ -536,23 +534,9 @@ class CollectDependenciesVisitor extends ReactiveFunctionVisitor<
       case 'JSXText':
       case 'BinaryExpression':
       case 'UnaryExpression': {
-        if (options.forceMemoizePrimitives) {
-          /**
-           * Because these instructions produce primitives we usually don't consider
-           * them as escape points: they are known to copy, not return references.
-           * However if we're forcing memoization of primitives then we mark these
-           * instructions as needing memoization and walk their rvalues to ensure
-           * any scopes transitively reachable from the rvalues are considered for
-           * memoization. Note: we may still prune primitive-producing scopes if
-           * they don't ultimately escape at all.
-           */
-          const level = MemoizationLevel.Memoized;
-          return {
-            lvalues: lvalue !== null ? [{place: lvalue, level}] : [],
-            rvalues: [...eachReactiveValueOperand(value)],
-          };
-        }
-        const level = MemoizationLevel.Never;
+        const level = options.forceMemoizePrimitives
+          ? MemoizationLevel.Memoized
+          : MemoizationLevel.Never;
         return {
           // All of these instructions return a primitive value and never need to be memoized
           lvalues: lvalue !== null ? [{place: lvalue, level}] : [],

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

@@ -284,7 +284,8 @@ function validateInferredDep(
     CompilerDiagnostic.create({
       category: ErrorCategory.PreserveManualMemo,
       severity: ErrorSeverity.CannotPreserveMemoization,
-      reason: 'Existing memoization could not be preserved',
+      reason:
+        'Compilation skipped because existing memoization could not be preserved',
       description: [
         'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. ',
         'The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. ',
@@ -538,7 +539,8 @@ class Visitor extends ReactiveFunctionVisitor<VisitorState> {
             CompilerDiagnostic.create({
               category: ErrorCategory.PreserveManualMemo,
               severity: ErrorSeverity.CannotPreserveMemoization,
-              reason: 'Existing memoization could not be preserved',
+              reason:
+                'Compilation skipped because existing memoization could not be preserved',
               description: [
                 'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. ',
                 'This dependency may be mutated later, which could cause the value to change unexpectedly.',
@@ -586,7 +588,8 @@ class Visitor extends ReactiveFunctionVisitor<VisitorState> {
                 CompilerDiagnostic.create({
                   category: ErrorCategory.PreserveManualMemo,
                   severity: ErrorSeverity.CannotPreserveMemoization,
-                  reason: 'Existing memoization could not be preserved',
+                  reason:
+                    'Compilation skipped because existing memoization could not be preserved',
                   description: [
                     'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output. ',
                     DEBUG

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/align-scopes-reactive-scope-overlaps-if.expect.md

@@ -46,16 +46,14 @@ function useFoo(t0) {
     t1 = $[0];
   }
   let items = t1;
-  if ($[1] !== cond) {
-    bb0: {
-      if (cond) {
-        items = [];
-      } else {
-        break bb0;
-      }
-
-      items.push(2);
+  bb0: if ($[1] !== cond) {
+    if (cond) {
+      items = [];
+    } else {
+      break bb0;
     }
+
+    items.push(2);
     $[1] = cond;
     $[2] = items;
   } else {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/dont-memoize-primitive-function-call-non-escaping-useMemo.expect.md

@@ -1,77 +0,0 @@
-
-## Input
-
-```javascript
-// @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import {useMemo} from 'react';
-import {makeObject_Primitives, ValidateMemoization} from 'shared-runtime';
-
-function Component(props) {
-  const result = useMemo(
-    () => makeObject(props.value).value + 1,
-    [props.value]
-  );
-  console.log(result);
-  return 'ok';
-}
-
-function makeObject(value) {
-  console.log(value);
-  return {value};
-}
-
-export const TODO_FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-  sequentialRenders: [
-    {value: 42},
-    {value: 42},
-    {value: 3.14},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-  ],
-};
-
-```
-
-## Code
-
-```javascript
-// @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import { useMemo } from "react";
-import { makeObject_Primitives, ValidateMemoization } from "shared-runtime";
-
-function Component(props) {
-  const result = makeObject(props.value).value + 1;
-
-  console.log(result);
-  return "ok";
-}
-
-function makeObject(value) {
-  console.log(value);
-  return { value };
-}
-
-export const TODO_FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{ value: 42 }],
-  sequentialRenders: [
-    { value: 42 },
-    { value: 42 },
-    { value: 3.14 },
-    { value: 3.14 },
-    { value: 42 },
-    { value: 3.14 },
-    { value: 42 },
-    { value: 3.14 },
-  ],
-};
-
-```
-      
-### Eval output
-(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/dont-memoize-primitive-function-call-non-escaping-useMemo.js

@@ -1,32 +0,0 @@
-// @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import {useMemo} from 'react';
-import {makeObject_Primitives, ValidateMemoization} from 'shared-runtime';
-
-function Component(props) {
-  const result = useMemo(
-    () => makeObject(props.value).value + 1,
-    [props.value]
-  );
-  console.log(result);
-  return 'ok';
-}
-
-function makeObject(value) {
-  console.log(value);
-  return {value};
-}
-
-export const TODO_FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-  sequentialRenders: [
-    {value: 42},
-    {value: 42},
-    {value: 3.14},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-  ],
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/dont-memoize-primitive-function-call-non-escaping.expect.md

@@ -1,81 +0,0 @@
-
-## Input
-
-```javascript
-// @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import {useMemo} from 'react';
-import {makeObject_Primitives, ValidateMemoization} from 'shared-runtime';
-
-function Component(props) {
-  const result = makeObject(props.value).value + 1;
-  console.log(result);
-  return 'ok';
-}
-
-function makeObject(value) {
-  console.log(value);
-  return {value};
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-  sequentialRenders: [
-    {value: 42},
-    {value: 42},
-    {value: 3.14},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-  ],
-};
-
-```
-
-## Code
-
-```javascript
-// @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import { useMemo } from "react";
-import { makeObject_Primitives, ValidateMemoization } from "shared-runtime";
-
-function Component(props) {
-  const result = makeObject(props.value).value + 1;
-  console.log(result);
-  return "ok";
-}
-
-function makeObject(value) {
-  console.log(value);
-  return { value };
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{ value: 42 }],
-  sequentialRenders: [
-    { value: 42 },
-    { value: 42 },
-    { value: 3.14 },
-    { value: 3.14 },
-    { value: 42 },
-    { value: 3.14 },
-    { value: 42 },
-    { value: 3.14 },
-  ],
-};
-
-```
-      
-### Eval output
-(kind: ok) "ok"
-"ok"
-"ok"
-"ok"
-"ok"
-"ok"
-"ok"
-"ok"
-logs: [42,43,42,43,3.14,4.140000000000001,3.14,4.140000000000001,42,43,3.14,4.140000000000001,42,43,3.14,4.140000000000001]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/dont-memoize-primitive-function-call-non-escaping.js

@@ -1,29 +0,0 @@
-// @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import {useMemo} from 'react';
-import {makeObject_Primitives, ValidateMemoization} from 'shared-runtime';
-
-function Component(props) {
-  const result = makeObject(props.value).value + 1;
-  console.log(result);
-  return 'ok';
-}
-
-function makeObject(value) {
-  console.log(value);
-  return {value};
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-  sequentialRenders: [
-    {value: 42},
-    {value: 42},
-    {value: 3.14},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-  ],
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.hoist-optional-member-expression-with-conditional-optional.expect.md

@@ -26,7 +26,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `props.items`, but the source dependencies were [props?.items, props.cond]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.hoist-optional-member-expression-with-conditional.expect.md

@@ -26,7 +26,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `props.items`, but the source dependencies were [props?.items, props.cond]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-known-incompatible-function.expect.md

@@ -1,34 +0,0 @@
-
-## Input
-
-```javascript
-import {knownIncompatible} from 'ReactCompilerKnownIncompatibleTest';
-
-function Component() {
-  const data = knownIncompatible();
-  return <div>Error</div>;
-}
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Compilation Skipped: Use of incompatible library
-
-This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized.
-
-error.invalid-known-incompatible-function.ts:4:15
-  2 |
-  3 | function Component() {
-> 4 |   const data = knownIncompatible();
-    |                ^^^^^^^^^^^^^^^^^ useKnownIncompatible is known to be incompatible
-  5 |   return <div>Error</div>;
-  6 | }
-  7 |
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-known-incompatible-function.js

@@ -1,6 +0,0 @@
-import {knownIncompatible} from 'ReactCompilerKnownIncompatibleTest';
-
-function Component() {
-  const data = knownIncompatible();
-  return <div>Error</div>;
-}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-known-incompatible-hook-return-property.expect.md

@@ -1,33 +0,0 @@
-
-## Input
-
-```javascript
-import {useKnownIncompatibleIndirect} from 'ReactCompilerKnownIncompatibleTest';
-
-function Component() {
-  const {incompatible} = useKnownIncompatibleIndirect();
-  return <div>{incompatible()}</div>;
-}
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Compilation Skipped: Use of incompatible library
-
-This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized.
-
-error.invalid-known-incompatible-hook-return-property.ts:5:15
-  3 | function Component() {
-  4 |   const {incompatible} = useKnownIncompatibleIndirect();
-> 5 |   return <div>{incompatible()}</div>;
-    |                ^^^^^^^^^^^^ useKnownIncompatibleIndirect returns an incompatible() function that is known incompatible
-  6 | }
-  7 |
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-known-incompatible-hook-return-property.js

@@ -1,6 +0,0 @@
-import {useKnownIncompatibleIndirect} from 'ReactCompilerKnownIncompatibleTest';
-
-function Component() {
-  const {incompatible} = useKnownIncompatibleIndirect();
-  return <div>{incompatible()}</div>;
-}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-known-incompatible-hook.expect.md

@@ -1,34 +0,0 @@
-
-## Input
-
-```javascript
-import {useKnownIncompatible} from 'ReactCompilerKnownIncompatibleTest';
-
-function Component() {
-  const data = useKnownIncompatible();
-  return <div>Error</div>;
-}
-
-```
-
-
-## Error
-
-```
-Found 1 error:
-
-Compilation Skipped: Use of incompatible library
-
-This API returns functions which cannot be memoized without leading to stale UI. To prevent this, by default React Compiler will skip memoizing this component/hook. However, you may see issues if values from this API are passed to other components/hooks that are memoized.
-
-error.invalid-known-incompatible-hook.ts:4:15
-  2 |
-  3 | function Component() {
-> 4 |   const data = useKnownIncompatible();
-    |                ^^^^^^^^^^^^^^^^^^^^ useKnownIncompatible is known to be incompatible
-  5 |   return <div>Error</div>;
-  6 | }
-  7 |
-```
-          
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-known-incompatible-hook.js

@@ -1,6 +0,0 @@
-import {useKnownIncompatible} from 'ReactCompilerKnownIncompatibleTest';
-
-function Component() {
-  const data = useKnownIncompatible();
-  return <div>Error</div>;
-}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-optional-member-expression-as-memo-dep-non-optional-in-body.expect.md

@@ -20,7 +20,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `props.items.edges.nodes`, but the source dependencies were [props.items?.edges?.nodes]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-useEffect-dep-not-memoized-bc-range-overlaps-hook.expect.md

@@ -25,7 +25,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
+Memoization: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
 
 error.invalid-useEffect-dep-not-memoized-bc-range-overlaps-hook.ts:9:2
    7 |

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-useEffect-dep-not-memoized.expect.md

@@ -22,7 +22,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
+Memoization: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
 
 error.invalid-useEffect-dep-not-memoized.ts:6:2
    4 | function Component(props) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-useInsertionEffect-dep-not-memoized.expect.md

@@ -22,7 +22,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
+Memoization: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
 
 error.invalid-useInsertionEffect-dep-not-memoized.ts:6:2
    4 | function Component(props) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-useLayoutEffect-dep-not-memoized.expect.md

@@ -22,7 +22,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
+Memoization: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
 
 error.invalid-useLayoutEffect-dep-not-memoized.ts:6:2
    4 | function Component(props) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.ref-like-name-not-Ref.expect.md

@@ -33,7 +33,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `Ref.current`, but the source dependencies were []. Inferred dependency not present in source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.ref-like-name-not-a-ref.expect.md

@@ -33,7 +33,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `notaref.current`, but the source dependencies were []. Inferred dependency not present in source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-repro-missed-memoization-from-capture-in-invoked-function-inferred-as-mutation.expect.md

@@ -44,7 +44,7 @@ component Component() {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-repro-missed-memoization-from-inferred-mutation-in-logger.expect.md

@@ -54,7 +54,7 @@ component Component(id) {
 ```
 Found 3 errors:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 
@@ -76,7 +76,7 @@ React Compiler has skipped optimizing this component because the existing manual
   18 |   const setCurrentIndex = useCallback(
   19 |     (index: number) => {
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly.
 
@@ -88,7 +88,7 @@ React Compiler has skipped optimizing this component because the existing manual
   30 |
   31 |   if (prevId !== id) {
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-repro-unmemoized-callback-captured-in-context-variable.expect.md

@@ -52,7 +52,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.validate-memoized-effect-deps-invalidated-dep-value.expect.md

@@ -30,7 +30,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
+Memoization: React Compiler has skipped optimizing this component because the effect dependencies could not be memoized. Unmemoized effect dependencies can trigger an infinite loop or other unexpected behavior
 
 error.validate-memoized-effect-deps-invalidated-dep-value.ts:11:2
    9 |   const y = [x];

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.validate-object-entries-mutation.expect.md

@@ -27,7 +27,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 2 errors:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly.
 
@@ -40,7 +40,7 @@ error.validate-object-entries-mutation.ts:6:57
   8 |     value.updated = true;
   9 |   });
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.validate-object-values-mutation.expect.md

@@ -27,7 +27,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 2 errors:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly.
 
@@ -40,7 +40,7 @@ error.validate-object-values-mutation.ts:6:55
   8 |     value.updated = true;
   9 |   });
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/gating/dynamic-gating-bailout-nopanic.expect.md

@@ -58,7 +58,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Logs
 
 ```
-{"kind":"CompileError","fnLoc":{"start":{"line":6,"column":0,"index":206},"end":{"line":16,"column":1,"index":433},"filename":"dynamic-gating-bailout-nopanic.ts"},"detail":{"options":{"category":"PreserveManualMemo","severity":"CannotPreserveMemoization","reason":"Existing memoization could not be preserved","description":"React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `value`, but the source dependencies were []. Inferred dependency not present in source.","suggestions":null,"details":[{"kind":"error","loc":{"start":{"line":9,"column":31,"index":288},"end":{"line":9,"column":52,"index":309},"filename":"dynamic-gating-bailout-nopanic.ts"},"message":"Could not preserve existing manual memoization"}]}}}
+{"kind":"CompileError","fnLoc":{"start":{"line":6,"column":0,"index":206},"end":{"line":16,"column":1,"index":433},"filename":"dynamic-gating-bailout-nopanic.ts"},"detail":{"options":{"category":"PreserveManualMemo","severity":"CannotPreserveMemoization","reason":"Compilation skipped because existing memoization could not be preserved","description":"React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `value`, but the source dependencies were []. Inferred dependency not present in source.","suggestions":null,"details":[{"kind":"error","loc":{"start":{"line":9,"column":31,"index":288},"end":{"line":9,"column":52,"index":309},"filename":"dynamic-gating-bailout-nopanic.ts"},"message":"Could not preserve existing manual memoization"}]}}}
 ```
       
 ### Eval output

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/memoize-primitive-function-calls.expect.md

@@ -1,107 +0,0 @@
-
-## Input
-
-```javascript
-// @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import {useMemo} from 'react';
-import {makeObject_Primitives, ValidateMemoization} from 'shared-runtime';
-
-function Component(props) {
-  const result = useMemo(() => {
-    return makeObject(props.value).value + 1;
-  }, [props.value]);
-  return <ValidateMemoization inputs={[props.value]} output={result} />;
-}
-
-function makeObject(value) {
-  console.log(value);
-  return {value};
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-  sequentialRenders: [
-    {value: 42},
-    {value: 42},
-    {value: 3.14},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-  ],
-};
-
-```
-
-## Code
-
-```javascript
-import { c as _c } from "react/compiler-runtime"; // @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import { useMemo } from "react";
-import { makeObject_Primitives, ValidateMemoization } from "shared-runtime";
-
-function Component(props) {
-  const $ = _c(7);
-  let t0;
-  if ($[0] !== props.value) {
-    t0 = makeObject(props.value);
-    $[0] = props.value;
-    $[1] = t0;
-  } else {
-    t0 = $[1];
-  }
-  const result = t0.value + 1;
-  let t1;
-  if ($[2] !== props.value) {
-    t1 = [props.value];
-    $[2] = props.value;
-    $[3] = t1;
-  } else {
-    t1 = $[3];
-  }
-  let t2;
-  if ($[4] !== result || $[5] !== t1) {
-    t2 = <ValidateMemoization inputs={t1} output={result} />;
-    $[4] = result;
-    $[5] = t1;
-    $[6] = t2;
-  } else {
-    t2 = $[6];
-  }
-  return t2;
-}
-
-function makeObject(value) {
-  console.log(value);
-  return { value };
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{ value: 42 }],
-  sequentialRenders: [
-    { value: 42 },
-    { value: 42 },
-    { value: 3.14 },
-    { value: 3.14 },
-    { value: 42 },
-    { value: 3.14 },
-    { value: 42 },
-    { value: 3.14 },
-  ],
-};
-
-```
-      
-### Eval output
-(kind: ok) <div>{"inputs":[42],"output":43}</div>
-<div>{"inputs":[42],"output":43}</div>
-<div>{"inputs":[3.14],"output":4.140000000000001}</div>
-<div>{"inputs":[3.14],"output":4.140000000000001}</div>
-<div>{"inputs":[42],"output":43}</div>
-<div>{"inputs":[3.14],"output":4.140000000000001}</div>
-<div>{"inputs":[42],"output":43}</div>
-<div>{"inputs":[3.14],"output":4.140000000000001}</div>
-logs: [42,3.14,42,3.14,42,3.14]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/memoize-primitive-function-calls.js

@@ -1,30 +0,0 @@
-// @compilationMode:"infer" @enablePreserveExistingMemoizationGuarantees @validatePreserveExistingMemoizationGuarantees
-import {useMemo} from 'react';
-import {makeObject_Primitives, ValidateMemoization} from 'shared-runtime';
-
-function Component(props) {
-  const result = useMemo(() => {
-    return makeObject(props.value).value + 1;
-  }, [props.value]);
-  return <ValidateMemoization inputs={[props.value]} output={result} />;
-}
-
-function makeObject(value) {
-  console.log(value);
-  return {value};
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{value: 42}],
-  sequentialRenders: [
-    {value: 42},
-    {value: 42},
-    {value: 3.14},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-    {value: 42},
-    {value: 3.14},
-  ],
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/mutation-within-jsx-and-break.expect.md

@@ -49,12 +49,12 @@ import {
 } from "shared-runtime";
 
 function useFoo(t0) {
-  const $ = _c(4);
+  const $ = _c(3);
   const { data } = t0;
   let obj;
   let myDiv = null;
-  if ($[0] !== data.cond || $[1] !== data.cond1) {
-    bb0: if (data.cond) {
+  bb0: if (data.cond) {
+    if ($[0] !== data.cond1) {
       obj = makeObject_Primitives();
       if (data.cond1) {
         myDiv = <Stringify value={mutateAndReturn(obj)} />;
@@ -62,14 +62,13 @@ function useFoo(t0) {
       }
 
       mutate(obj);
+      $[0] = data.cond1;
+      $[1] = obj;
+      $[2] = myDiv;
+    } else {
+      obj = $[1];
+      myDiv = $[2];
     }
-    $[0] = data.cond;
-    $[1] = data.cond1;
-    $[2] = obj;
-    $[3] = myDiv;
-  } else {
-    obj = $[2];
-    myDiv = $[3];
   }
   return myDiv;
 }

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/error.invalid-useCallback-captures-reassigned-context.expect.md

@@ -31,7 +31,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 2 errors:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly.
 
@@ -44,7 +44,7 @@ error.invalid-useCallback-captures-reassigned-context.ts:11:37
   13 |   x = makeArray();
   14 |
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

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

@@ -32,7 +32,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

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

@@ -31,7 +31,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.false-positive-useMemo-overlap-scopes.expect.md

@@ -42,7 +42,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.hoist-useCallback-conditional-access-own-scope.expect.md

@@ -28,7 +28,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propB`, but the source dependencies were [propA, propB.x.y]. Inferred less specific property than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.hoist-useCallback-infer-conditional-value-block.expect.md

@@ -31,7 +31,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 2 errors:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propA`, but the source dependencies were [propA.a, propB.x.y]. Inferred less specific property than source.
 
@@ -60,7 +60,7 @@ error.hoist-useCallback-infer-conditional-value-block.ts:6:21
   16 |
   17 | export const FIXTURE_ENTRYPOINT = {
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propB`, but the source dependencies were [propA.a, propB.x.y]. Inferred less specific property than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.invalid-useCallback-captures-reassigned-context.expect.md

@@ -32,7 +32,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 2 errors:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This dependency may be mutated later, which could cause the value to change unexpectedly.
 
@@ -45,7 +45,7 @@ error.invalid-useCallback-captures-reassigned-context.ts:12:37
   14 |   x = makeArray();
   15 |
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.preserve-use-memo-ref-missing-reactive.expect.md

@@ -30,7 +30,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `ref`, but the source dependencies were []. Inferred dependency not present in source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.todo-useCallback-captures-invalidating-value.expect.md

@@ -30,7 +30,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useCallback-aliased-var.expect.md

@@ -21,7 +21,7 @@ function useHook(x) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `aliasedX`, but the source dependencies were [x, aliasedProp]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useCallback-conditional-access-noAlloc.expect.md

@@ -27,7 +27,7 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propB?.x.y`, but the source dependencies were [propA, propB.x.y]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useCallback-infer-less-specific-conditional-access.expect.md

@@ -26,7 +26,7 @@ function Component({propA, propB}) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propB`, but the source dependencies were [propA?.a, propB.x.y]. Inferred less specific property than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useCallback-property-call-dep.expect.md

@@ -19,7 +19,7 @@ function Component({propA}) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propA`, but the source dependencies were [propA.x]. Inferred less specific property than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useMemo-aliased-var.expect.md

@@ -21,7 +21,7 @@ function useHook(x) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `x`, but the source dependencies were [aliasedX, aliasedProp]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useMemo-infer-less-specific-conditional-access.expect.md

@@ -26,7 +26,7 @@ function Component({propA, propB}) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propB`, but the source dependencies were [propA?.a, propB.x.y]. Inferred less specific property than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useMemo-infer-less-specific-conditional-value-block.expect.md

@@ -26,7 +26,7 @@ function Component({propA, propB}) {
 ```
 Found 2 errors:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propA`, but the source dependencies were [propA.a, propB.x.y]. Inferred less specific property than source.
 
@@ -54,7 +54,7 @@ error.useMemo-infer-less-specific-conditional-value-block.ts:6:17
   15 | }
   16 |
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propB`, but the source dependencies were [propA.a, propB.x.y]. Inferred less specific property than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useMemo-property-call-chained-object.expect.md

@@ -21,7 +21,7 @@ function Component({propA}) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propA`, but the source dependencies were [propA.x]. Inferred less specific property than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useMemo-property-call-dep.expect.md

@@ -19,7 +19,7 @@ function Component({propA}) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `propA`, but the source dependencies were [propA.x]. Inferred less specific property than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/preserve-memo-validation/error.useMemo-unrelated-mutation-in-depslist.expect.md

@@ -32,7 +32,7 @@ function useFoo(input1) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `input1`, but the source dependencies were [y]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/propagate-scope-deps-hir-fork/error.todo-optional-member-expression-with-conditional-optional.expect.md

@@ -26,7 +26,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `props.items`, but the source dependencies were [props?.items, props.cond]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/propagate-scope-deps-hir-fork/error.todo-optional-member-expression-with-conditional.expect.md

@@ -26,7 +26,7 @@ function Component(props) {
 ```
 Found 1 error:
 
-Compilation Skipped: Existing memoization could not be preserved
+Memoization: Compilation skipped because existing memoization could not be preserved
 
 React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. The inferred dependency was `props.items`, but the source dependencies were [props?.items, props.cond]. Inferred different dependency than source.
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/propagate-scope-deps-hir-fork/useMemo-multiple-if-else.expect.md

@@ -34,16 +34,17 @@ import { c as _c } from "react/compiler-runtime"; // @enablePropagateDepsInHIR
 import { useMemo } from "react";
 
 function Component(props) {
-  const $ = _c(5);
+  const $ = _c(6);
   let t0;
-  if (
-    $[0] !== props.a ||
-    $[1] !== props.b ||
-    $[2] !== props.cond ||
-    $[3] !== props.cond2
-  ) {
-    bb0: {
-      const y = [];
+  bb0: {
+    let y;
+    if (
+      $[0] !== props.a ||
+      $[1] !== props.b ||
+      $[2] !== props.cond ||
+      $[3] !== props.cond2
+    ) {
+      y = [];
       if (props.cond) {
         y.push(props.a);
       }
@@ -53,15 +54,17 @@ function Component(props) {
       }
 
       y.push(props.b);
-      t0 = y;
+      $[0] = props.a;
+      $[1] = props.b;
+      $[2] = props.cond;
+      $[3] = props.cond2;
+      $[4] = y;
+      $[5] = t0;
+    } else {
+      y = $[4];
+      t0 = $[5];
     }
-    $[0] = props.a;
-    $[1] = props.b;
-    $[2] = props.cond;
-    $[3] = props.cond2;
-    $[4] = t0;
-  } else {
-    t0 = $[4];
+    t0 = y;
   }
   const x = t0;
   return x;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-useMemo-if-else-both-early-return.expect.md

@@ -1,118 +0,0 @@
-
-## Input
-
-```javascript
-import {useMemo} from 'react';
-import {
-  makeObject_Primitives,
-  mutate,
-  Stringify,
-  ValidateMemoization,
-} from 'shared-runtime';
-
-function Component({cond}) {
-  const memoized = useMemo(() => {
-    const value = makeObject_Primitives();
-    if (cond) {
-      return value;
-    } else {
-      mutate(value);
-      return value;
-    }
-  }, [cond]);
-  return <ValidateMemoization inputs={[cond]} output={memoized} />;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{cond: false}],
-  sequentialRenders: [
-    {cond: false},
-    {cond: false},
-    {cond: true},
-    {cond: true},
-    {cond: false},
-    {cond: true},
-    {cond: false},
-    {cond: true},
-  ],
-};
-
-```
-
-## Code
-
-```javascript
-import { c as _c } from "react/compiler-runtime";
-import { useMemo } from "react";
-import {
-  makeObject_Primitives,
-  mutate,
-  Stringify,
-  ValidateMemoization,
-} from "shared-runtime";
-
-function Component(t0) {
-  const $ = _c(7);
-  const { cond } = t0;
-  let t1;
-  if ($[0] !== cond) {
-    const value = makeObject_Primitives();
-    if (cond) {
-      t1 = value;
-    } else {
-      mutate(value);
-      t1 = value;
-    }
-    $[0] = cond;
-    $[1] = t1;
-  } else {
-    t1 = $[1];
-  }
-  const memoized = t1;
-  let t2;
-  if ($[2] !== cond) {
-    t2 = [cond];
-    $[2] = cond;
-    $[3] = t2;
-  } else {
-    t2 = $[3];
-  }
-  let t3;
-  if ($[4] !== memoized || $[5] !== t2) {
-    t3 = <ValidateMemoization inputs={t2} output={memoized} />;
-    $[4] = memoized;
-    $[5] = t2;
-    $[6] = t3;
-  } else {
-    t3 = $[6];
-  }
-  return t3;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{ cond: false }],
-  sequentialRenders: [
-    { cond: false },
-    { cond: false },
-    { cond: true },
-    { cond: true },
-    { cond: false },
-    { cond: true },
-    { cond: false },
-    { cond: true },
-  ],
-};
-
-```
-      
-### Eval output
-(kind: ok) <div>{"inputs":[false],"output":{"a":0,"b":"value1","c":true,"wat0":"joe"}}</div>
-<div>{"inputs":[false],"output":{"a":0,"b":"value1","c":true,"wat0":"joe"}}</div>
-<div>{"inputs":[true],"output":{"a":0,"b":"value1","c":true}}</div>
-<div>{"inputs":[true],"output":{"a":0,"b":"value1","c":true}}</div>
-<div>{"inputs":[false],"output":{"a":0,"b":"value1","c":true,"wat0":"joe"}}</div>
-<div>{"inputs":[true],"output":{"a":0,"b":"value1","c":true}}</div>
-<div>{"inputs":[false],"output":{"a":0,"b":"value1","c":true,"wat0":"joe"}}</div>
-<div>{"inputs":[true],"output":{"a":0,"b":"value1","c":true}}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-useMemo-if-else-both-early-return.js

@@ -1,35 +0,0 @@
-import {useMemo} from 'react';
-import {
-  makeObject_Primitives,
-  mutate,
-  Stringify,
-  ValidateMemoization,
-} from 'shared-runtime';
-
-function Component({cond}) {
-  const memoized = useMemo(() => {
-    const value = makeObject_Primitives();
-    if (cond) {
-      return value;
-    } else {
-      mutate(value);
-      return value;
-    }
-  }, [cond]);
-  return <ValidateMemoization inputs={[cond]} output={memoized} />;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: Component,
-  params: [{cond: false}],
-  sequentialRenders: [
-    {cond: false},
-    {cond: false},
-    {cond: true},
-    {cond: true},
-    {cond: false},
-    {cond: true},
-    {cond: false},
-    {cond: true},
-  ],
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/useMemo-multiple-if-else.expect.md

@@ -33,16 +33,17 @@ import { c as _c } from "react/compiler-runtime";
 import { useMemo } from "react";
 
 function Component(props) {
-  const $ = _c(5);
+  const $ = _c(6);
   let t0;
-  if (
-    $[0] !== props.a ||
-    $[1] !== props.b ||
-    $[2] !== props.cond ||
-    $[3] !== props.cond2
-  ) {
-    bb0: {
-      const y = [];
+  bb0: {
+    let y;
+    if (
+      $[0] !== props.a ||
+      $[1] !== props.b ||
+      $[2] !== props.cond ||
+      $[3] !== props.cond2
+    ) {
+      y = [];
       if (props.cond) {
         y.push(props.a);
       }
@@ -52,15 +53,17 @@ function Component(props) {
       }
 
       y.push(props.b);
-      t0 = y;
+      $[0] = props.a;
+      $[1] = props.b;
+      $[2] = props.cond;
+      $[3] = props.cond2;
+      $[4] = y;
+      $[5] = t0;
+    } else {
+      y = $[4];
+      t0 = $[5];
     }
-    $[0] = props.a;
-    $[1] = props.b;
-    $[2] = props.cond;
-    $[3] = props.cond2;
-    $[4] = t0;
-  } else {
-    t0 = $[4];
+    t0 = y;
   }
   const x = t0;
   return x;

compiler/packages/snap/src/sprout/shared-runtime-type-provider.ts

@@ -198,51 +198,6 @@ export function makeSharedRuntimeTypeProvider({
           },
         },
       };
-    } else if (moduleName === 'ReactCompilerKnownIncompatibleTest') {
-      /**
-       * Fake module used for testing validation of known incompatible
-       * API validation
-       */
-      return {
-        kind: 'object',
-        properties: {
-          useKnownIncompatible: {
-            kind: 'hook',
-            positionalParams: [],
-            restParam: EffectEnum.Read,
-            returnType: {kind: 'type', name: 'Any'},
-            knownIncompatible: `useKnownIncompatible is known to be incompatible`,
-          },
-          useKnownIncompatibleIndirect: {
-            kind: 'hook',
-            positionalParams: [],
-            restParam: EffectEnum.Read,
-            returnType: {
-              kind: 'object',
-              properties: {
-                incompatible: {
-                  kind: 'function',
-                  positionalParams: [],
-                  restParam: EffectEnum.Read,
-                  calleeEffect: EffectEnum.Read,
-                  returnType: {kind: 'type', name: 'Any'},
-                  returnValueKind: ValueKindEnum.Mutable,
-                  knownIncompatible: `useKnownIncompatibleIndirect returns an incompatible() function that is known incompatible`,
-                },
-              },
-            },
-          },
-          knownIncompatible: {
-            kind: 'function',
-            positionalParams: [],
-            restParam: EffectEnum.Read,
-            calleeEffect: EffectEnum.Read,
-            returnType: {kind: 'type', name: 'Any'},
-            returnValueKind: ValueKindEnum.Mutable,
-            knownIncompatible: `useKnownIncompatible is known to be incompatible`,
-          },
-        },
-      };
     } else if (moduleName === 'ReactCompilerTest') {
       /**
        * Fake module used for testing validation that type providers return hook

compiler/scripts/copy-fixtures.sh

@@ -1,20 +0,0 @@
-#!/bin/bash
-# Create the output directory if it doesn't exist
-mkdir -p ./preserve-existing-memoization-guarantees
-# Store the results of the rg command into a variable
-rg_results=$(rg enablePreserveExistingMemoizationGuarantees -l)
-# Iterate over each line stored in the variable
-while IFS= read -r path; do
-  # Skip if not a .js file
-  if [[ "$path" != *.js ]]; then
-    continue
-  fi
-  # Remove the .js extension
-  base="${path%.js}"
-  # Construct destination paths
-  preserve="./preserve-existing-memoization-guarantees/${base}-preserve.js"
-  dont_preserve="./preserve-existing-memoization-guarantees/${base}-dont-preserve.js"
-  # Copy the file to both destinations
-  cp "$path" "$preserve"
-  cp "$path" "$dont_preserve"
-done <<< "$rg_results"

packages/eslint-plugin-react-hooks/README.md

@@ -22,22 +22,15 @@ yarn add eslint-plugin-react-hooks --dev
 
 #### >= 6.0.0
 
-For users of 6.0 and beyond, add the `recommended` config.
+For users of 6.0 and beyond, simply add the `recommended` config.
 
 ```js
-// eslint.config.js
-import reactHooks from 'eslint-plugin-react-hooks';
-import { defineConfig } from 'eslint/config';
+import * as reactHooks from 'eslint-plugin-react-hooks';
 
-export default defineConfig([
-  {
-    files: ["src/**/*.{js,jsx,ts,tsx}"],
-    plugins: {
-      'react-hooks': reactHooks,
-    },
-    extends: ['react-hooks/recommended'],
-  },
-]);
+export default [
+  // ...
+  reactHooks.configs.recommended,
+];
 ```
 
 #### 5.2.0
@@ -45,18 +38,12 @@ export default defineConfig([
 For users of 5.2.0 (the first version with flat config support), add the `recommended-latest` config.
 
 ```js
-import reactHooks from 'eslint-plugin-react-hooks';
-import { defineConfig } from 'eslint/config';
+import * as reactHooks from 'eslint-plugin-react-hooks';
 
-export default defineConfig([
-  {
-    files: ["src/**/*.{js,jsx,ts,tsx}"],
-    plugins: {
-      'react-hooks': reactHooks,
-    },
-    extends: ['react-hooks/recommended-latest'],
-  },
-]);
+export default [
+  // ...
+  reactHooks.configs['recommended-latest'],
+];
 ```
 
 ### Legacy Config (.eslintrc)