[compiler][newinference] Error handling and related fixes

Lots of small fixes related to error handling. InferMutationAliasRanges now tracks transitive calls that may mutate frozen or global values. We properly populate and track the reason each value has the kind it has, to use when throwing errors for invalid mutations (can't mutate state vs can't mutate a captured jsx value, etc). When we infer mutation effects for inner functions, we populate the location of mutations as the location where the mutation occurred, not the declaration of the captured value (aside: this was quite involved to do in the old inference, it's trivial here). A bunch of other small fixes that make sense in context.

And some of our "bug-*" fixtures output changes...becasue the new inference fixes the bugs. One example included here.

ghstack-source-id: 2c11291351
Pull Request resolved: https://github.com/facebook/react/pull/33458

compiler/.gitignore

@@ -6,6 +6,9 @@
 debug/
 target/
 
+nocommit*.js
+nocommit*.expect.md
+
 # These are backup files generated by rustfmt
 **/*.rs.bk
 

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

@@ -115,6 +115,14 @@ export class CompilerErrorDetail {
 export class CompilerError extends Error {
   details: Array<CompilerErrorDetail> = [];
 
+  static from(details: Array<CompilerErrorDetailOptions>): CompilerError {
+    const error = new CompilerError();
+    for (const detail of details) {
+      error.push(detail);
+    }
+    return error;
+  }
+
   static invariant(
     condition: unknown,
     options: Omit<CompilerErrorDetailOptions, 'severity'>,

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

@@ -104,6 +104,8 @@ import {validateNoImpureFunctionsInRender} from '../Validation/ValidateNoImpureF
 import {CompilerError} from '..';
 import {validateStaticComponents} from '../Validation/ValidateStaticComponents';
 import {validateNoFreezingKnownMutableFunctions} from '../Validation/ValidateNoFreezingKnownMutableFunctions';
+import {inferMutationAliasingEffects} from '../Inference/InferMutationAliasingEffects';
+import {inferMutationAliasingRanges} from '../Inference/InferMutationAliasingRanges';
 
 export type CompilerPipelineValue =
   | {kind: 'ast'; name: string; value: CodegenFunction}
@@ -226,15 +228,27 @@ function runWithEnvironment(
   analyseFunctions(hir);
   log({kind: 'hir', name: 'AnalyseFunctions', value: hir});
 
-  const fnEffectErrors = inferReferenceEffects(hir);
-  if (env.isInferredMemoEnabled) {
-    if (fnEffectErrors.length > 0) {
-      CompilerError.throw(fnEffectErrors[0]);
+  if (!env.config.enableNewMutationAliasingModel) {
+    const fnEffectErrors = inferReferenceEffects(hir);
+    if (env.isInferredMemoEnabled) {
+      if (fnEffectErrors.length > 0) {
+        CompilerError.throw(fnEffectErrors[0]);
+      }
+    }
+    log({kind: 'hir', name: 'InferReferenceEffects', value: hir});
+  } else {
+    const mutabilityAliasingErrors = inferMutationAliasingEffects(hir);
+    log({kind: 'hir', name: 'InferMutationAliasingEffects', value: hir});
+    if (env.isInferredMemoEnabled) {
+      if (mutabilityAliasingErrors.isErr()) {
+        throw mutabilityAliasingErrors.unwrapErr();
+      }
     }
   }
-  log({kind: 'hir', name: 'InferReferenceEffects', value: hir});
 
-  validateLocalsNotReassignedAfterRender(hir);
+  if (!env.config.enableNewMutationAliasingModel) {
+    validateLocalsNotReassignedAfterRender(hir);
+  }
 
   // Note: Has to come after infer reference effects because "dead" code may still affect inference
   deadCodeElimination(hir);
@@ -248,8 +262,20 @@ function runWithEnvironment(
   pruneMaybeThrows(hir);
   log({kind: 'hir', name: 'PruneMaybeThrows', value: hir});
 
-  inferMutableRanges(hir);
-  log({kind: 'hir', name: 'InferMutableRanges', value: hir});
+  if (!env.config.enableNewMutationAliasingModel) {
+    inferMutableRanges(hir);
+    log({kind: 'hir', name: 'InferMutableRanges', value: hir});
+  } else {
+    const mutabilityAliasingErrors = inferMutationAliasingRanges(hir, {
+      isFunctionExpression: false,
+    });
+    log({kind: 'hir', name: 'InferMutationAliasingRanges', value: hir});
+    if (env.isInferredMemoEnabled) {
+      if (mutabilityAliasingErrors.isErr()) {
+        throw mutabilityAliasingErrors.unwrapErr();
+      }
+    }
+  }
 
   if (env.isInferredMemoEnabled) {
     if (env.config.assertValidMutableRanges) {

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

@@ -47,7 +47,7 @@ import {
   makeType,
   promoteTemporary,
 } from './HIR';
-import HIRBuilder, {Bindings} from './HIRBuilder';
+import HIRBuilder, {Bindings, createTemporaryPlace} from './HIRBuilder';
 import {BuiltInArrayId} from './ObjectShape';
 
 /*
@@ -179,6 +179,7 @@ export function lower(
       loc: GeneratedSource,
       value: lowerExpressionToTemporary(builder, body),
       id: makeInstructionId(0),
+      effects: null,
     };
     builder.terminateWithContinuation(terminal, fallthrough);
   } else if (body.isBlockStatement()) {
@@ -208,6 +209,7 @@ export function lower(
         loc: GeneratedSource,
       }),
       id: makeInstructionId(0),
+      effects: null,
     },
     null,
   );
@@ -218,6 +220,7 @@ export function lower(
     fnType: parent == null ? env.fnType : 'Other',
     returnTypeAnnotation: null, // TODO: extract the actual return type node if present
     returnType: makeType(),
+    returns: createTemporaryPlace(env, func.node.loc ?? GeneratedSource),
     body: builder.build(),
     context,
     generator: func.node.generator === true,
@@ -225,6 +228,7 @@ export function lower(
     loc: func.node.loc ?? GeneratedSource,
     env,
     effects: null,
+    aliasingEffects: null,
     directives,
   });
 }
@@ -285,6 +289,7 @@ function lowerStatement(
         loc: stmt.node.loc ?? GeneratedSource,
         value,
         id: makeInstructionId(0),
+        effects: null,
       };
       builder.terminate(terminal, 'block');
       return;
@@ -1235,6 +1240,7 @@ function lowerStatement(
           kind: 'Debugger',
           loc,
         },
+        effects: null,
         loc,
       });
       return;
@@ -1892,6 +1898,7 @@ function lowerExpression(
           place: leftValue,
           loc: exprLoc,
         },
+        effects: null,
         loc: exprLoc,
       });
       builder.terminateWithContinuation(
@@ -2827,6 +2834,7 @@ function lowerOptionalCallExpression(
           args,
           loc,
         },
+        effects: null,
         loc,
       });
     } else {
@@ -2840,6 +2848,7 @@ function lowerOptionalCallExpression(
           args,
           loc,
         },
+        effects: null,
         loc,
       });
     }
@@ -3466,9 +3475,10 @@ function lowerValueToTemporary(
   const place: Place = buildTemporaryPlace(builder, value.loc);
   builder.push({
     id: makeInstructionId(0),
-    value: value,
-    loc: value.loc,
     lvalue: {...place},
+    value: value,
+    effects: null,
+    loc: value.loc,
   });
   return place;
 }

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

@@ -243,6 +243,11 @@ export const EnvironmentConfigSchema = z.object({
    */
   enableUseTypeAnnotations: z.boolean().default(false),
 
+  /**
+   * Enable a new model for mutability and aliasing inference
+   */
+  enableNewMutationAliasingModel: z.boolean().default(true),
+
   /**
    * Enables inference of optional dependency chains. Without this flag
    * a property chain such as `props?.items?.foo` will infer as a dep on

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

@@ -13,6 +13,7 @@ import {Environment, ReactFunctionType} from './Environment';
 import type {HookKind} from './ObjectShape';
 import {Type, makeType} from './Types';
 import {z} from 'zod';
+import {AliasingEffect} from '../Inference/InferMutationAliasingEffects';
 
 /*
  * *******************************************************************************************
@@ -100,6 +101,7 @@ export type ReactiveInstruction = {
   id: InstructionId;
   lvalue: Place | null;
   value: ReactiveValue;
+  effects?: Array<AliasingEffect> | null; // TODO make non-optional
   loc: SourceLocation;
 };
 
@@ -278,12 +280,14 @@ export type HIRFunction = {
   params: Array<Place | SpreadPattern>;
   returnTypeAnnotation: t.FlowType | t.TSType | null;
   returnType: Type;
+  returns: Place;
   context: Array<Place>;
   effects: Array<FunctionEffect> | null;
   body: HIR;
   generator: boolean;
   async: boolean;
   directives: Array<string>;
+  aliasingEffects?: Array<AliasingEffect> | null;
 };
 
 export type FunctionEffect =
@@ -300,6 +304,10 @@ export type FunctionEffect =
       places: ReadonlySet<Place>;
       effect: Effect;
       loc: SourceLocation;
+    }
+  | {
+      kind: 'CaptureEffect';
+      places: ReadonlySet<Place>;
     };
 
 /*
@@ -449,6 +457,7 @@ export type ReturnTerminal = {
   value: Place;
   id: InstructionId;
   fallthrough?: never;
+  effects: Array<AliasingEffect> | null;
 };
 
 export type GotoTerminal = {
@@ -609,6 +618,7 @@ export type MaybeThrowTerminal = {
   id: InstructionId;
   loc: SourceLocation;
   fallthrough?: never;
+  effects: Array<AliasingEffect> | null;
 };
 
 export type ReactiveScopeTerminal = {
@@ -645,12 +655,18 @@ export type Instruction = {
   lvalue: Place;
   value: InstructionValue;
   loc: SourceLocation;
+  effects: Array<AliasingEffect> | null;
 };
 
+export function todoPopulateAliasingEffects(): Array<AliasingEffect> | null {
+  return null;
+}
+
 export type TInstruction<T extends InstructionValue> = {
   id: InstructionId;
   lvalue: Place;
   value: T;
+  effects: Array<AliasingEffect> | null;
   loc: SourceLocation;
 };
 

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

@@ -165,6 +165,7 @@ export default class HIRBuilder {
           handler: exceptionHandler,
           id: makeInstructionId(0),
           loc: instruction.loc,
+          effects: null,
         },
         continuationBlock,
       );

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

@@ -12,6 +12,7 @@ import {
   GeneratedSource,
   HIRFunction,
   Instruction,
+  Place,
 } from './HIR';
 import {markPredecessors} from './HIRBuilder';
 import {terminalFallthrough, terminalHasFallthrough} from './visitors';
@@ -80,20 +81,22 @@ export function mergeConsecutiveBlocks(fn: HIRFunction): void {
         suggestions: null,
       });
       const operand = Array.from(phi.operands.values())[0]!;
+      const lvalue: Place = {
+        kind: 'Identifier',
+        identifier: phi.place.identifier,
+        effect: Effect.ConditionallyMutate,
+        reactive: false,
+        loc: GeneratedSource,
+      };
       const instr: Instruction = {
         id: predecessor.terminal.id,
-        lvalue: {
-          kind: 'Identifier',
-          identifier: phi.place.identifier,
-          effect: Effect.ConditionallyMutate,
-          reactive: false,
-          loc: GeneratedSource,
-        },
+        lvalue: {...lvalue},
         value: {
           kind: 'LoadLocal',
           place: {...operand},
           loc: GeneratedSource,
         },
+        effects: [{kind: 'Alias', from: {...operand}, into: {...lvalue}}],
         loc: GeneratedSource,
       };
       predecessor.instructions.push(instr);

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

@@ -6,10 +6,21 @@
  */
 
 import {CompilerError} from '../CompilerError';
-import {Effect, ValueKind, ValueReason} from './HIR';
+import {AliasingSignature} from '../Inference/InferMutationAliasingEffects';
+import {
+  Effect,
+  GeneratedSource,
+  makeDeclarationId,
+  makeIdentifierId,
+  makeInstructionId,
+  Place,
+  ValueKind,
+  ValueReason,
+} from './HIR';
 import {
   BuiltInType,
   FunctionType,
+  makeType,
   ObjectType,
   PolyType,
   PrimitiveType,
@@ -179,6 +190,9 @@ export type FunctionSignature = {
   impure?: boolean;
 
   canonicalName?: string;
+
+  aliasing?: AliasingSignature | null;
+  todo_aliasing?: AliasingSignature | null;
 };
 
 /*
@@ -302,6 +316,30 @@ addObject(BUILTIN_SHAPES, BuiltInArrayId, [
       returnType: PRIMITIVE_TYPE,
       calleeEffect: Effect.Store,
       returnValueKind: ValueKind.Primitive,
+      aliasing: {
+        receiver: makeIdentifierId(0),
+        params: [],
+        rest: makeIdentifierId(1),
+        returns: makeIdentifierId(2),
+        temporaries: [],
+        effects: [
+          // Push directly mutates the array itself
+          {kind: 'Mutate', value: signatureArgument(0)},
+          // The arguments are captured into the array
+          {
+            kind: 'Capture',
+            from: signatureArgument(1),
+            into: signatureArgument(0),
+          },
+          // Returns the new length, a primitive
+          {
+            kind: 'Create',
+            into: signatureArgument(2),
+            value: ValueKind.Primitive,
+            reason: ValueReason.KnownReturnSignature,
+          },
+        ],
+      },
     }),
   ],
   [
@@ -332,6 +370,61 @@ addObject(BUILTIN_SHAPES, BuiltInArrayId, [
       returnValueKind: ValueKind.Mutable,
       noAlias: true,
       mutableOnlyIfOperandsAreMutable: true,
+      aliasing: {
+        receiver: makeIdentifierId(0),
+        params: [makeIdentifierId(1)],
+        rest: null,
+        returns: makeIdentifierId(2),
+        temporaries: [
+          // Temporary representing captured items of the receiver
+          signatureArgument(3),
+          // Temporary representing the result of the callback
+          signatureArgument(4),
+          /*
+           * Undefined `this` arg to the callback. Note the signature does not
+           * support passing an explicit thisArg second param
+           */
+          signatureArgument(5),
+        ],
+        effects: [
+          // Map creates a new mutable array
+          {
+            kind: 'Create',
+            into: signatureArgument(2),
+            value: ValueKind.Mutable,
+            reason: ValueReason.KnownReturnSignature,
+          },
+          // The first arg to the callback is an item extracted from the receiver array
+          {
+            kind: 'CreateFrom',
+            from: signatureArgument(0),
+            into: signatureArgument(3),
+          },
+          // The undefined this for the callback
+          {
+            kind: 'Create',
+            into: signatureArgument(5),
+            value: ValueKind.Primitive,
+            reason: ValueReason.KnownReturnSignature,
+          },
+          // calls the callback, returning the result into a temporary
+          {
+            kind: 'Apply',
+            receiver: signatureArgument(5),
+            args: [signatureArgument(3), {kind: 'Hole'}, signatureArgument(0)],
+            function: signatureArgument(1),
+            into: signatureArgument(4),
+            signature: null,
+            mutatesFunction: false,
+          },
+          // captures the result of the callback into the return array
+          {
+            kind: 'Capture',
+            from: signatureArgument(4),
+            into: signatureArgument(2),
+          },
+        ],
+      },
     }),
   ],
   [
@@ -479,6 +572,32 @@ addObject(BUILTIN_SHAPES, BuiltInSetId, [
       calleeEffect: Effect.Store,
       // returnValueKind is technically dependent on the ValueKind of the set itself
       returnValueKind: ValueKind.Mutable,
+      aliasing: {
+        receiver: makeIdentifierId(0),
+        params: [],
+        rest: makeIdentifierId(1),
+        returns: makeIdentifierId(2),
+        temporaries: [],
+        effects: [
+          // Set.add returns the receiver Set
+          {
+            kind: 'Assign',
+            from: signatureArgument(0),
+            into: signatureArgument(2),
+          },
+          // Set.add mutates the set itself
+          {
+            kind: 'Mutate',
+            value: signatureArgument(0),
+          },
+          // Captures the rest params into the set
+          {
+            kind: 'Capture',
+            from: signatureArgument(1),
+            into: signatureArgument(0),
+          },
+        ],
+      },
     }),
   ],
   [
@@ -1169,3 +1288,22 @@ export const DefaultNonmutatingHook = addHook(
   },
   'DefaultNonmutatingHook',
 );
+
+export function signatureArgument(id: number): Place {
+  const place: Place = {
+    kind: 'Identifier',
+    effect: Effect.Unknown,
+    loc: GeneratedSource,
+    reactive: false,
+    identifier: {
+      declarationId: makeDeclarationId(id),
+      id: makeIdentifierId(id),
+      loc: GeneratedSource,
+      mutableRange: {start: makeInstructionId(0), end: makeInstructionId(0)},
+      name: null,
+      scope: null,
+      type: makeType(),
+    },
+  };
+  return place;
+}

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

@@ -35,6 +35,10 @@ import type {
   Type,
 } from './HIR';
 import {GotoVariant, InstructionKind} from './HIR';
+import {
+  AliasingEffect,
+  AliasingSignature,
+} from '../Inference/InferMutationAliasingEffects';
 
 export type Options = {
   indent: number;
@@ -67,13 +71,15 @@ export function printFunction(fn: HIRFunction): string {
         })
         .join(', ') +
       ')';
+  } else {
+    definition += '()';
   }
   if (definition.length !== 0) {
     output.push(definition);
   }
-  output.push(printType(fn.returnType));
-  output.push(printHIR(fn.body));
+  output.push(`: ${printType(fn.returnType)} @ ${printPlace(fn.returns)}`);
   output.push(...fn.directives);
+  output.push(printHIR(fn.body));
   return output.join('\n');
 }
 
@@ -151,7 +157,10 @@ export function printMixedHIR(
 
 export function printInstruction(instr: ReactiveInstruction): string {
   const id = `[${instr.id}]`;
-  const value = printInstructionValue(instr.value);
+  let value = printInstructionValue(instr.value);
+  if (instr.effects != null) {
+    value += `\n    ${instr.effects.map(printAliasingEffect).join('\n    ')}`;
+  }
 
   if (instr.lvalue !== null) {
     return `${id} ${printPlace(instr.lvalue)} = ${value}`;
@@ -213,6 +222,9 @@ export function printTerminal(terminal: Terminal): Array<string> | string {
       value = `[${terminal.id}] Return${
         terminal.value != null ? ' ' + printPlace(terminal.value) : ''
       }`;
+      if (terminal.effects != null) {
+        value += `\n    ${terminal.effects.map(printAliasingEffect).join('\n    ')}`;
+      }
       break;
     }
     case 'goto': {
@@ -281,6 +293,9 @@ export function printTerminal(terminal: Terminal): Array<string> | string {
     }
     case 'maybe-throw': {
       value = `[${terminal.id}] MaybeThrow continuation=bb${terminal.continuation} handler=bb${terminal.handler}`;
+      if (terminal.effects != null) {
+        value += `\n    ${terminal.effects.map(printAliasingEffect).join('\n    ')}`;
+      }
       break;
     }
     case 'scope': {
@@ -546,17 +561,31 @@ export function printInstructionValue(instrValue: ReactiveValue): string {
       const effects =
         instrValue.loweredFunc.func.effects
           ?.map(effect => {
-            if (effect.kind === 'ContextMutation') {
-              return `ContextMutation places=[${[...effect.places]
-                .map(place => printPlace(place))
-                .join(', ')}] effect=${effect.effect}`;
-            } else {
-              return `GlobalMutation`;
+            switch (effect.kind) {
+              case 'ContextMutation': {
+                return `ContextMutation places=[${[...effect.places]
+                  .map(place => printPlace(place))
+                  .join(', ')}] effect=${effect.effect}`;
+              }
+              case 'GlobalMutation': {
+                return 'GlobalMutation';
+              }
+              case 'ReactMutation': {
+                return 'ReactMutation';
+              }
+              case 'CaptureEffect': {
+                return `CaptureEffect places=[${[...effect.places]
+                  .map(place => printPlace(place))
+                  .join(', ')}]`;
+              }
             }
           })
           .join(', ') ?? '';
-      const type = printType(instrValue.loweredFunc.func.returnType).trim();
-      value = `${kind} ${name} @context[${context}] @effects[${effects}]${type !== '' ? ` return${type}` : ''}:\n${fn}`;
+      const aliasingEffects =
+        instrValue.loweredFunc.func.aliasingEffects
+          ?.map(printAliasingEffect)
+          ?.join(', ') ?? '';
+      value = `${kind} ${name} @context[${context}] @effects[${effects}] @aliasingEffects=[${aliasingEffects}]\n${fn}`;
       break;
     }
     case 'TaggedTemplateExpression': {
@@ -720,7 +749,7 @@ function isMutable(range: MutableRange): boolean {
 }
 
 const DEBUG_MUTABLE_RANGES = false;
-function printMutableRange(identifier: Identifier): string {
+export function printMutableRange(identifier: Identifier): string {
   if (DEBUG_MUTABLE_RANGES) {
     // if debugging, print both the identifier and scope range if they differ
     const range = identifier.mutableRange;
@@ -922,3 +951,101 @@ function getFunctionName(
       return defaultValue;
   }
 }
+
+export function printAliasingEffect(effect: AliasingEffect): string {
+  switch (effect.kind) {
+    case 'Assign': {
+      return `Assign ${printPlaceForAliasEffect(effect.into)} = ${printPlaceForAliasEffect(effect.from)}`;
+    }
+    case 'Alias': {
+      return `Alias ${printPlaceForAliasEffect(effect.into)} = ${printPlaceForAliasEffect(effect.from)}`;
+    }
+    case 'Capture': {
+      return `Capture ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;
+    }
+    case 'ImmutableCapture': {
+      return `ImmutableCapture ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;
+    }
+    case 'Create': {
+      return `Create ${printPlaceForAliasEffect(effect.into)} = ${effect.value}`;
+    }
+    case 'CreateFrom': {
+      return `Create ${printPlaceForAliasEffect(effect.into)} = kindOf(${printPlaceForAliasEffect(effect.from)})`;
+    }
+    case 'CreateFunction': {
+      return `Function ${printPlaceForAliasEffect(effect.into)} = Function captures=[${effect.captures.map(printPlaceForAliasEffect).join(', ')}]`;
+    }
+    case 'Apply': {
+      const receiverCallee =
+        effect.receiver.identifier.id === effect.function.identifier.id
+          ? printPlaceForAliasEffect(effect.receiver)
+          : `${printPlaceForAliasEffect(effect.receiver)}.${printPlaceForAliasEffect(effect.function)}`;
+      const args = effect.args
+        .map(arg => {
+          if (arg.kind === 'Identifier') {
+            return printPlaceForAliasEffect(arg);
+          } else if (arg.kind === 'Hole') {
+            return ' ';
+          }
+          return `...${printPlaceForAliasEffect(arg.place)}`;
+        })
+        .join(', ');
+      let signature = '';
+      if (effect.signature != null) {
+        if (effect.signature.aliasing != null) {
+          signature = printAliasingSignature(effect.signature.aliasing);
+        } else {
+          signature = JSON.stringify(effect.signature, null, 2);
+        }
+      }
+      return `Apply ${printPlaceForAliasEffect(effect.into)} = ${receiverCallee}(${args})${signature != '' ? '\n     ' : ''}${signature}`;
+    }
+    case 'Freeze': {
+      return `Freeze ${printPlaceForAliasEffect(effect.value)} ${effect.reason}`;
+    }
+    case 'Mutate':
+    case 'MutateConditionally':
+    case 'MutateTransitive':
+    case 'MutateTransitiveConditionally': {
+      return `${effect.kind} ${printPlaceForAliasEffect(effect.value)}`;
+    }
+    case 'MutateFrozen': {
+      return `MutateFrozen ${printPlaceForAliasEffect(effect.place)} reason=${JSON.stringify(effect.error.reason)}`;
+    }
+    case 'MutateGlobal': {
+      return `MutateGlobal ${printPlaceForAliasEffect(effect.place)} reason=${JSON.stringify(effect.error.reason)}`;
+    }
+    default: {
+      assertExhaustive(effect, `Unexpected kind '${(effect as any).kind}'`);
+    }
+  }
+}
+
+function printPlaceForAliasEffect(place: Place): string {
+  return printIdentifier(place.identifier);
+}
+
+export function printAliasingSignature(signature: AliasingSignature): string {
+  const tokens: Array<string> = ['function '];
+  if (signature.temporaries.length !== 0) {
+    tokens.push('<');
+    tokens.push(
+      signature.temporaries.map(temp => `$${temp.identifier.id}`).join(', '),
+    );
+    tokens.push('>');
+  }
+  tokens.push('(');
+  tokens.push('this=$' + String(signature.receiver));
+  for (const param of signature.params) {
+    tokens.push(', $' + String(param));
+  }
+  if (signature.rest != null) {
+    tokens.push(`, ...$${String(signature.rest)}`);
+  }
+  tokens.push('): ');
+  tokens.push('$' + String(signature.returns) + ':');
+  for (const effect of signature.effects) {
+    tokens.push('\n  ' + printAliasingEffect(effect));
+  }
+  return tokens.join('');
+}

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

@@ -735,6 +735,7 @@ export function mapTerminalSuccessors(
         loc: terminal.loc,
         value: terminal.value,
         id: makeInstructionId(0),
+        effects: terminal.effects,
       };
     }
     case 'throw': {
@@ -842,6 +843,7 @@ export function mapTerminalSuccessors(
         handler,
         id: makeInstructionId(0),
         loc: terminal.loc,
+        effects: terminal.effects,
       };
     }
     case 'try': {

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

@@ -10,7 +10,9 @@ import {
   Effect,
   HIRFunction,
   Identifier,
+  IdentifierId,
   LoweredFunction,
+  Place,
   isRefOrRefValue,
   makeInstructionId,
 } from '../HIR';
@@ -19,6 +21,15 @@ import {inferReactiveScopeVariables} from '../ReactiveScopes';
 import {rewriteInstructionKindsBasedOnReassignment} from '../SSA';
 import {inferMutableRanges} from './InferMutableRanges';
 import inferReferenceEffects from './InferReferenceEffects';
+import DisjointSet from '../Utils/DisjointSet';
+import {
+  eachInstructionLValue,
+  eachInstructionValueOperand,
+} from '../HIR/visitors';
+import {assertExhaustive, Iterable_some} from '../Utils/utils';
+import {inferMutationAliasingEffects} from './InferMutationAliasingEffects';
+import {inferMutationAliasingFunctionEffects} from './InferMutationAliasingFunctionEffects';
+import {inferMutationAliasingRanges} from './InferMutationAliasingRanges';
 
 export default function analyseFunctions(func: HIRFunction): void {
   for (const [_, block] of func.body.blocks) {
@@ -26,8 +37,12 @@ export default function analyseFunctions(func: HIRFunction): void {
       switch (instr.value.kind) {
         case 'ObjectMethod':
         case 'FunctionExpression': {
-          lower(instr.value.loweredFunc.func);
-          infer(instr.value.loweredFunc);
+          if (!func.env.config.enableNewMutationAliasingModel) {
+            const aliases = lower(instr.value.loweredFunc.func);
+            infer(instr.value.loweredFunc, aliases);
+          } else {
+            lowerWithMutationAliasing(instr.value.loweredFunc.func);
+          }
 
           /**
            * Reset mutable range for outer inferReferenceEffects
@@ -44,11 +59,82 @@ export default function analyseFunctions(func: HIRFunction): void {
   }
 }
 
-function lower(func: HIRFunction): void {
+function lowerWithMutationAliasing(fn: HIRFunction): void {
+  analyseFunctions(fn);
+  inferMutationAliasingEffects(fn, {isFunctionExpression: true});
+  deadCodeElimination(fn);
+  inferMutationAliasingRanges(fn, {isFunctionExpression: true});
+  rewriteInstructionKindsBasedOnReassignment(fn);
+  inferReactiveScopeVariables(fn);
+  const effects = inferMutationAliasingFunctionEffects(fn);
+  fn.env.logger?.debugLogIRs?.({
+    kind: 'hir',
+    name: 'AnalyseFunction (inner)',
+    value: fn,
+  });
+  if (effects != null) {
+    fn.aliasingEffects ??= [];
+    fn.aliasingEffects?.push(...effects);
+  }
+
+  const capturedOrMutated = new Set<IdentifierId>();
+  for (const effect of effects ?? []) {
+    switch (effect.kind) {
+      case 'Assign':
+      case 'Alias':
+      case 'Capture':
+      case 'CreateFrom': {
+        capturedOrMutated.add(effect.from.identifier.id);
+        break;
+      }
+      case 'Apply': {
+        CompilerError.invariant(false, {
+          reason: `[AnalyzeFunctions] Expected Apply effects to be replaced with more precise effects`,
+          loc: effect.function.loc,
+        });
+      }
+      case 'Mutate':
+      case 'MutateConditionally':
+      case 'MutateTransitive':
+      case 'MutateTransitiveConditionally': {
+        capturedOrMutated.add(effect.value.identifier.id);
+        break;
+      }
+      case 'MutateFrozen':
+      case 'MutateGlobal':
+      case 'CreateFunction':
+      case 'Create':
+      case 'Freeze':
+      case 'ImmutableCapture': {
+        // no-op
+        break;
+      }
+      default: {
+        assertExhaustive(
+          effect,
+          `Unexpected effect kind ${(effect as any).kind}`,
+        );
+      }
+    }
+  }
+
+  for (const operand of fn.context) {
+    if (
+      capturedOrMutated.has(operand.identifier.id) ||
+      operand.effect === Effect.Capture
+    ) {
+      operand.effect = Effect.Capture;
+    } else {
+      operand.effect = Effect.Read;
+    }
+  }
+}
+
+function lower(func: HIRFunction): DisjointSet<Identifier> {
   analyseFunctions(func);
   inferReferenceEffects(func, {isFunctionExpression: true});
   deadCodeElimination(func);
-  inferMutableRanges(func);
+  const aliases = inferMutableRanges(func);
   rewriteInstructionKindsBasedOnReassignment(func);
   inferReactiveScopeVariables(func);
   func.env.logger?.debugLogIRs?.({
@@ -56,9 +142,61 @@ function lower(func: HIRFunction): void {
     name: 'AnalyseFunction (inner)',
     value: func,
   });
+  inferAliasesForCapturing(func, aliases);
+  return aliases ?? new DisjointSet();
 }
 
-function infer(loweredFunc: LoweredFunction): void {
+/**
+ * The alias sets returned by InferMutableRanges() accounts only for aliases that
+ * are known to mutate together. Notably this skips cases where a value is captured
+ * into some other value, but neither is subsequently mutated. An example is pushing
+ * a mutable value onto an array, where neither the array or value are subsequently
+ * mutated.
+ *
+ * This function extends the aliases sets to account for such capturing, so that we
+ * can detect cases where one of the values in a set is mutated later (in an outer function)
+ * we can correctly infer them as mutating together.
+ */
+function inferAliasesForCapturing(
+  fn: HIRFunction,
+  aliases: DisjointSet<Identifier>,
+): void {
+  for (const block of fn.body.blocks.values()) {
+    for (const instr of block.instructions) {
+      const {lvalue, value} = instr;
+      const hasCapture =
+        lvalue.effect === Effect.Store ||
+        Iterable_some(
+          eachInstructionValueOperand(value),
+          operand => operand.effect === Effect.Capture,
+        );
+      if (!hasCapture) {
+        continue;
+      }
+      const operands: Array<Identifier> = [];
+      for (const lvalue of eachInstructionLValue(instr)) {
+        operands.push(lvalue.identifier);
+      }
+      for (const operand of eachInstructionValueOperand(instr.value)) {
+        if (
+          operand.effect === Effect.Store ||
+          operand.effect === Effect.Mutate ||
+          operand.effect === Effect.Capture
+        ) {
+          operands.push(operand.identifier);
+        }
+      }
+      if (operands.length > 1) {
+        aliases.union(operands);
+      }
+    }
+  }
+}
+
+function infer(
+  loweredFunc: LoweredFunction,
+  aliases: DisjointSet<Identifier>,
+): void {
   for (const operand of loweredFunc.func.context) {
     const identifier = operand.identifier;
     CompilerError.invariant(operand.effect === Effect.Unknown, {
@@ -85,6 +223,23 @@ function infer(loweredFunc: LoweredFunction): void {
       operand.effect = Effect.Read;
     }
   }
+  const contextIdentifiers = new Map(
+    loweredFunc.func.context.map(place => [place.identifier, place]),
+  );
+  for (const set of aliases.buildSets()) {
+    const contextOperands: Set<Place> = new Set(
+      [...set]
+        .map(identifier => contextIdentifiers.get(identifier))
+        .filter(place => place != null) as Array<Place>,
+    );
+    if (contextOperands.size !== 0) {
+      loweredFunc.func.effects ??= [];
+      loweredFunc.func.effects?.push({
+        kind: 'CaptureEffect',
+        places: contextOperands,
+      });
+    }
+  }
 }
 
 function isMutatedOrReassigned(id: Identifier): boolean {

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

@@ -197,6 +197,7 @@ function makeManualMemoizationMarkers(
         deps: depsList,
         loc: fnExpr.loc,
       },
+      effects: null,
       loc: fnExpr.loc,
     },
     {
@@ -208,6 +209,7 @@ function makeManualMemoizationMarkers(
         decl: {...memoDecl},
         loc: fnExpr.loc,
       },
+      effects: null,
       loc: fnExpr.loc,
     },
   ];

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

@@ -60,6 +60,10 @@ function inferInstr(
       alias = instrValue.value;
       break;
     }
+    case 'IteratorNext': {
+      alias = instrValue.collection;
+      break;
+    }
     default:
       return;
   }

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

@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {HIRFunction, Identifier} from '../HIR/HIR';
+import DisjointSet from '../Utils/DisjointSet';
+
+export function inferAliasForFunctionCaptureEffects(
+  func: HIRFunction,
+  aliases: DisjointSet<Identifier>,
+): void {
+  for (const [_, block] of func.body.blocks) {
+    for (const instr of block.instructions) {
+      const {value} = instr;
+      if (
+        value.kind !== 'FunctionExpression' &&
+        value.kind !== 'ObjectMethod'
+      ) {
+        continue;
+      }
+      const loweredFunction = value.loweredFunc.func;
+      for (const effect of loweredFunction.effects ?? []) {
+        if (effect.kind !== 'CaptureEffect') {
+          continue;
+        }
+        aliases.union([...effect.places].map(place => place.identifier));
+      }
+    }
+  }
+}

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

@@ -29,6 +29,7 @@ import {
   isSetStateType,
   isFireFunctionType,
   makeScopeId,
+  todoPopulateAliasingEffects,
 } from '../HIR';
 import {collectHoistablePropertyLoadsInInnerFn} from '../HIR/CollectHoistablePropertyLoads';
 import {collectOptionalChainSidemap} from '../HIR/CollectOptionalChainDependencies';
@@ -236,9 +237,10 @@ export function inferEffectDependencies(fn: HIRFunction): void {
 
             newInstructions.push({
               id: makeInstructionId(0),
-              loc: GeneratedSource,
               lvalue: {...depsPlace, effect: Effect.Mutate},
+              effects: todoPopulateAliasingEffects(),
               value: deps,
+              loc: GeneratedSource,
             });
 
             // Step 2: push the inferred deps array as an argument of the useEffect
@@ -249,9 +251,10 @@ export function inferEffectDependencies(fn: HIRFunction): void {
             // Global functions have no reactive dependencies, so we can insert an empty array
             newInstructions.push({
               id: makeInstructionId(0),
-              loc: GeneratedSource,
               lvalue: {...depsPlace, effect: Effect.Mutate},
+              effects: todoPopulateAliasingEffects(),
               value: deps,
+              loc: GeneratedSource,
             });
             value.args.push({...depsPlace, effect: Effect.Freeze});
             rewriteInstrs.set(instr.id, newInstructions);
@@ -316,21 +319,25 @@ function writeDependencyToInstructions(
   const instructions: Array<Instruction> = [];
   let currValue = createTemporaryPlace(env, GeneratedSource);
   currValue.reactive = reactive;
+  const dependencyPlace: Place = {
+    kind: 'Identifier',
+    identifier: dep.identifier,
+    effect: Effect.Capture,
+    reactive,
+    loc: loc,
+  };
   instructions.push({
     id: makeInstructionId(0),
     loc: GeneratedSource,
     lvalue: {...currValue, effect: Effect.Mutate},
     value: {
       kind: 'LoadLocal',
-      place: {
-        kind: 'Identifier',
-        identifier: dep.identifier,
-        effect: Effect.Capture,
-        reactive,
-        loc: loc,
-      },
+      place: {...dependencyPlace},
       loc: loc,
     },
+    effects: [
+      {kind: 'Alias', from: {...dependencyPlace}, into: {...currValue}},
+    ],
   });
   for (const path of dep.path) {
     if (path.optional) {
@@ -359,6 +366,7 @@ function writeDependencyToInstructions(
         property: path.property,
         loc: loc,
       },
+      effects: [{kind: 'Capture', from: {...currValue}, into: {...nextValue}}],
     });
     currValue = nextValue;
   }

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

@@ -95,45 +95,58 @@ function inheritFunctionEffects(
 
   return effects
     .flatMap(effect => {
-      if (effect.kind === 'GlobalMutation' || effect.kind === 'ReactMutation') {
-        return [effect];
-      } else {
-        const effects: Array<FunctionEffect | null> = [];
-        CompilerError.invariant(effect.kind === 'ContextMutation', {
-          reason: 'Expected ContextMutation',
-          loc: null,
-        });
-        /**
-         * Contextual effects need to be replayed against the current inference
-         * state, which may know more about the value to which the effect applied.
-         * The main cases are:
-         * 1. The mutated context value is _still_ a context value in the current scope,
-         *    so we have to continue propagating the original context mutation.
-         * 2. The mutated context value is a mutable value in the current scope,
-         *    so the context mutation was fine and we can skip propagating the effect.
-         * 3. The mutated context value  is an immutable value in the current scope,
-         *    resulting in a non-ContextMutation FunctionEffect. We propagate that new,
-         *    more detailed effect to the current function context.
-         */
-        for (const place of effect.places) {
-          if (state.isDefined(place)) {
-            const replayedEffect = inferOperandEffect(state, {
-              ...place,
-              loc: effect.loc,
-              effect: effect.effect,
-            });
-            if (replayedEffect != null) {
-              if (replayedEffect.kind === 'ContextMutation') {
-                // Case 1, still a context value so propagate the original effect
-                effects.push(effect);
-              } else {
-                // Case 3, immutable value so propagate the more precise effect
-                effects.push(replayedEffect);
-              }
-            } // else case 2, local mutable value so this effect was fine
-          }
+      switch (effect.kind) {
+        case 'GlobalMutation':
+        case 'ReactMutation': {
+          return [effect];
+        }
+        case 'ContextMutation': {
+          const effects: Array<FunctionEffect | null> = [];
+          CompilerError.invariant(effect.kind === 'ContextMutation', {
+            reason: 'Expected ContextMutation',
+            loc: null,
+          });
+          /**
+           * Contextual effects need to be replayed against the current inference
+           * state, which may know more about the value to which the effect applied.
+           * The main cases are:
+           * 1. The mutated context value is _still_ a context value in the current scope,
+           *    so we have to continue propagating the original context mutation.
+           * 2. The mutated context value is a mutable value in the current scope,
+           *    so the context mutation was fine and we can skip propagating the effect.
+           * 3. The mutated context value  is an immutable value in the current scope,
+           *    resulting in a non-ContextMutation FunctionEffect. We propagate that new,
+           *    more detailed effect to the current function context.
+           */
+          for (const place of effect.places) {
+            if (state.isDefined(place)) {
+              const replayedEffect = inferOperandEffect(state, {
+                ...place,
+                loc: effect.loc,
+                effect: effect.effect,
+              });
+              if (replayedEffect != null) {
+                if (replayedEffect.kind === 'ContextMutation') {
+                  // Case 1, still a context value so propagate the original effect
+                  effects.push(effect);
+                } else {
+                  // Case 3, immutable value so propagate the more precise effect
+                  effects.push(replayedEffect);
+                }
+              } // else case 2, local mutable value so this effect was fine
+            }
+          }
+          return effects;
+        }
+        case 'CaptureEffect': {
+          return [];
+        }
+        default: {
+          assertExhaustive(
+            effect,
+            `Unexpected effect kind '${(effect as any).kind}'`,
+          );
         }
-        return effects;
       }
     })
     .filter((effect): effect is FunctionEffect => effect != null);
@@ -298,33 +311,38 @@ export function inferTerminalFunctionEffects(
 export function transformFunctionEffectErrors(
   functionEffects: Array<FunctionEffect>,
 ): Array<CompilerErrorDetailOptions> {
-  return functionEffects.map(eff => {
-    switch (eff.kind) {
-      case 'ReactMutation':
-      case 'GlobalMutation': {
-        return eff.error;
+  return functionEffects
+    .map(eff => {
+      switch (eff.kind) {
+        case 'ReactMutation':
+        case 'GlobalMutation': {
+          return eff.error;
+        }
+        case 'ContextMutation': {
+          return {
+            severity: ErrorSeverity.Invariant,
+            reason: `Unexpected ContextMutation in top-level function effects`,
+            loc: eff.loc,
+          };
+        }
+        case 'CaptureEffect': {
+          return null;
+        }
+        default:
+          assertExhaustive(
+            eff,
+            `Unexpected function effect kind \`${(eff as any).kind}\``,
+          );
       }
-      case 'ContextMutation': {
-        return {
-          severity: ErrorSeverity.Invariant,
-          reason: `Unexpected ContextMutation in top-level function effects`,
-          loc: eff.loc,
-        };
-      }
-      default:
-        assertExhaustive(
-          eff,
-          `Unexpected function effect kind \`${(eff as any).kind}\``,
-        );
-    }
-  });
+    })
+    .filter(eff => eff != null) as Array<CompilerErrorDetailOptions>;
 }
 
 function isEffectSafeOutsideRender(effect: FunctionEffect): boolean {
   return effect.kind === 'GlobalMutation';
 }
 
-function getWriteErrorReason(abstractValue: AbstractValue): string {
+export function getWriteErrorReason(abstractValue: AbstractValue): string {
   if (abstractValue.reason.has(ValueReason.Global)) {
     return 'Writing to a variable defined outside a component or hook is not allowed. Consider using an effect';
   } else if (abstractValue.reason.has(ValueReason.JsxCaptured)) {

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

@@ -5,16 +5,21 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import prettyFormat from 'pretty-format';
 import {HIRFunction, Identifier} from '../HIR/HIR';
+import DisjointSet from '../Utils/DisjointSet';
 import {inferAliasForUncalledFunctions} from './InerAliasForUncalledFunctions';
 import {inferAliases} from './InferAlias';
+import {inferAliasForFunctionCaptureEffects} from './InferAliasesForFunctionCaptureEffects';
 import {inferAliasForPhis} from './InferAliasForPhis';
 import {inferAliasForStores} from './InferAliasForStores';
 import {inferMutableLifetimes} from './InferMutableLifetimes';
 import {inferMutableRangesForAlias} from './InferMutableRangesForAlias';
+import {inferMutableRangesForComutation} from './InferMutableRangesForComutation';
 import {inferTryCatchAliases} from './InferTryCatchAliases';
+import {printIdentifier} from '../HIR/PrintHIR';
 
-export function inferMutableRanges(ir: HIRFunction): void {
+export function inferMutableRanges(ir: HIRFunction): DisjointSet<Identifier> {
   // Infer mutable ranges for non fields
   inferMutableLifetimes(ir, false);
 
@@ -30,18 +35,22 @@ export function inferMutableRanges(ir: HIRFunction): void {
    * Eagerly canonicalize so that if nothing changes we can bail out
    * after a single iteration
    */
-  let prevAliases: Map<Identifier, Identifier> = aliases.canonicalize();
+  let prevAliases: Map<Identifier, string> = canonicalize(aliases);
   while (true) {
     // Infer mutable ranges for aliases that are not fields
     inferMutableRangesForAlias(ir, aliases);
 
+    inferMutableRangesForComutation(ir);
+
     // Update aliasing information of fields
     inferAliasForStores(ir, aliases);
 
+    inferAliasForFunctionCaptureEffects(ir, aliases);
+
     // Update aliasing information of phis
     inferAliasForPhis(ir, aliases);
 
-    const nextAliases = aliases.canonicalize();
+    const nextAliases = canonicalize(aliases);
     if (areEqualMaps(prevAliases, nextAliases)) {
       break;
     }
@@ -73,20 +82,58 @@ export function inferMutableRanges(ir: HIRFunction): void {
    * but does not modify values that `y` "contains" such as the
    * object literal or `z`.
    */
-  prevAliases = aliases.canonicalize();
+  prevAliases = canonicalize(aliases);
   while (true) {
     inferMutableRangesForAlias(ir, aliases);
+    inferMutableRangesForComutation(ir);
     inferAliasForPhis(ir, aliases);
     inferAliasForUncalledFunctions(ir, aliases);
-    const nextAliases = aliases.canonicalize();
+    const nextAliases = canonicalize(aliases);
     if (areEqualMaps(prevAliases, nextAliases)) {
       break;
     }
     prevAliases = nextAliases;
   }
+
+  return aliases;
 }
 
-function areEqualMaps<T>(a: Map<T, T>, b: Map<T, T>): boolean {
+export function debugAliases(aliases: DisjointSet<Identifier>): void {
+  console.log(
+    prettyFormat(
+      aliases
+        .buildSets()
+        .map(set =>
+          [...set].map(
+            ident =>
+              `${printIdentifier(ident)}:${ident.mutableRange.start}:${ident.mutableRange.end}`,
+          ),
+        ),
+    ),
+  );
+}
+
+/**
+ * Canonicalizes the alias set and mutable range information calculated at the current time.
+ * The returned value maps each identifier in the program to the root identifier of its alias
+ * set and the the mutable range of that set.
+ *
+ * This ensures that we fixpoint the mutable ranges themselves and not just the alias sets.
+ */
+export function canonicalize(
+  aliases: DisjointSet<Identifier>,
+): Map<Identifier, string> {
+  const entries = new Map<Identifier, string>();
+  aliases.forEach((item, root) => {
+    entries.set(
+      item,
+      `${root.id}:${root.mutableRange.start}:${root.mutableRange.end}`,
+    );
+  });
+  return entries;
+}
+
+export function areEqualMaps<T, U>(a: Map<T, U>, b: Map<T, U>): boolean {
   if (a.size !== b.size) {
     return false;
   }

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

@@ -0,0 +1,91 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {
+  HIRFunction,
+  Identifier,
+  isRefOrRefValue,
+  makeInstructionId,
+} from '../HIR';
+import {eachInstructionOperand} from '../HIR/visitors';
+import {isMutable} from '../ReactiveScopes/InferReactiveScopeVariables';
+
+/**
+ * Finds instructions with operands that co-mutate and extends all their mutable ranges
+ * to end at the same point (the highest `end` value of the group). Note that the
+ * alias sets used in InferMutableRanges are meant for values that strictly alias:
+ * a mutation of one value in the set would directly modify the same object as some
+ * other value in the set.
+ *
+ * However, co-mutation can cause an alias to one object to be stored within another object,
+ * for example:
+ *
+ * ```
+ * const a = {};
+ * const b = {};
+ * const f = () => b.c; //
+ * setProperty(a, 'b', b); // equiv to a.b = b
+ *
+ * a.b.c = 'c'; // this mutates b!
+ * ```
+ *
+ * Here, the co-mutation in `setProperty(a, 'b', b)` means that a reference to b may be stored
+ * in a, vice-versa, or both. We need to extend the mutable range of both a and b to reflect
+ * the fact the values may mutate together.
+ *
+ * Previously this was implemented in InferReactiveScopeVariables, but that is too late:
+ * we need this to be part of the InferMutableRanges fixpoint iteration to account for functions
+ * like `f` in the example, which capture a reference to a value that may change later. `f`
+ * cannot be independently memoized from the `setProperty()` call due to the co-mutation.
+ *
+ * See aliased-capture-mutate and aliased-capture-aliased-mutate fixtures for examples.
+ */
+export function inferMutableRangesForComutation(fn: HIRFunction): void {
+  for (const block of fn.body.blocks.values()) {
+    for (const instr of block.instructions) {
+      let operands: Array<Identifier> | null = null;
+      for (const operand of eachInstructionOperand(instr)) {
+        if (
+          isMutable(instr, operand) &&
+          operand.identifier.mutableRange.start > 0
+        ) {
+          if (
+            instr.value.kind === 'FunctionExpression' ||
+            instr.value.kind === 'ObjectMethod'
+          ) {
+            if (operand.identifier.type.kind === 'Primitive') {
+              continue;
+            }
+          }
+          operands ??= [];
+          operands.push(operand.identifier);
+        }
+      }
+      if (operands != null) {
+        // Find the last instruction which mutates any of the mutable operands
+        let lastMutatingInstructionId = makeInstructionId(0);
+        for (const id of operands) {
+          if (id.mutableRange.end > lastMutatingInstructionId) {
+            lastMutatingInstructionId = id.mutableRange.end;
+          }
+        }
+
+        /**
+         * Update all mutable operands's mutable ranges to end at the same point
+         */
+        for (const id of operands) {
+          if (
+            id.mutableRange.end < lastMutatingInstructionId &&
+            !isRefOrRefValue(id)
+          ) {
+            id.mutableRange.end = lastMutatingInstructionId;
+          }
+        }
+      }
+    }
+  }
+}

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

@@ -0,0 +1,185 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {HIRFunction, IdentifierId, Place, ValueKind, ValueReason} from '../HIR';
+import {getOrInsertDefault} from '../Utils/utils';
+import {AliasingEffect} from './InferMutationAliasingEffects';
+
+export function inferMutationAliasingFunctionEffects(
+  fn: HIRFunction,
+): Array<AliasingEffect> | null {
+  const effects: Array<AliasingEffect> = [];
+
+  /**
+   * Map used to identify tracked variables: params, context vars, return value
+   * This is used to detect mutation/capturing/aliasing of params/context vars
+   */
+  const tracked = new Map<IdentifierId, Place>();
+  tracked.set(fn.returns.identifier.id, fn.returns);
+  for (const operand of [...fn.context, ...fn.params]) {
+    const place = operand.kind === 'Identifier' ? operand : operand.place;
+    tracked.set(place.identifier.id, place);
+  }
+
+  /**
+   * Track capturing/aliasing of context vars and params into each other and into the return.
+   * We don't need to track locals and intermediate values, since we're only concerned with effects
+   * as they relate to arguments visible outside the function.
+   *
+   * For each aliased identifier we track capture/alias/createfrom and then merge this with how
+   * the value is used. Eg capturing an alias => capture. See joinEffects() helper.
+   */
+  type AliasedIdentifier = {
+    kind: AliasingKind;
+    place: Place;
+  };
+  const dataFlow = new Map<IdentifierId, Array<AliasedIdentifier>>();
+
+  /*
+   * Check for aliasing of tracked values. Also joins the effects of how the value is
+   * used (@param kind) with the aliasing type of each value
+   */
+  function lookup(
+    place: Place,
+    kind: AliasedIdentifier['kind'],
+  ): Array<AliasedIdentifier> | null {
+    if (tracked.has(place.identifier.id)) {
+      return [{kind, place}];
+    }
+    return (
+      dataFlow.get(place.identifier.id)?.map(aliased => ({
+        kind: joinEffects(aliased.kind, kind),
+        place: aliased.place,
+      })) ?? null
+    );
+  }
+
+  // todo: fixpoint
+  for (const block of fn.body.blocks.values()) {
+    for (const phi of block.phis) {
+      const operands: Array<AliasedIdentifier> = [];
+      for (const operand of phi.operands.values()) {
+        const inputs = lookup(operand, 'Alias');
+        if (inputs != null) {
+          operands.push(...inputs);
+        }
+      }
+      if (operands.length !== 0) {
+        dataFlow.set(phi.place.identifier.id, operands);
+      }
+    }
+    for (const instr of block.instructions) {
+      if (instr.effects == null) continue;
+      for (const effect of instr.effects) {
+        if (
+          effect.kind === 'Assign' ||
+          effect.kind === 'Capture' ||
+          effect.kind === 'Alias' ||
+          effect.kind === 'CreateFrom'
+        ) {
+          const from = lookup(effect.from, effect.kind);
+          if (from == null) {
+            continue;
+          }
+          const into = lookup(effect.into, 'Alias');
+          if (into == null) {
+            getOrInsertDefault(dataFlow, effect.into.identifier.id, []).push(
+              ...from,
+            );
+          } else {
+            for (const aliased of into) {
+              getOrInsertDefault(
+                dataFlow,
+                aliased.place.identifier.id,
+                [],
+              ).push(...from);
+            }
+          }
+        } else if (
+          effect.kind === 'Create' ||
+          effect.kind === 'CreateFunction'
+        ) {
+          getOrInsertDefault(dataFlow, effect.into.identifier.id, [
+            {kind: 'Alias', place: effect.into},
+          ]);
+        } else if (
+          effect.kind === 'MutateFrozen' ||
+          effect.kind === 'MutateGlobal'
+        ) {
+          effects.push(effect);
+        }
+      }
+    }
+    if (block.terminal.kind === 'return') {
+      const from = lookup(block.terminal.value, 'Alias');
+      if (from != null) {
+        getOrInsertDefault(dataFlow, fn.returns.identifier.id, []).push(
+          ...from,
+        );
+      }
+    }
+  }
+
+  // Create aliasing effects based on observed data flow
+  let hasReturn = false;
+  for (const [into, from] of dataFlow) {
+    const input = tracked.get(into);
+    if (input == null) {
+      continue;
+    }
+    for (const aliased of from) {
+      if (
+        aliased.place.identifier.id === input.identifier.id ||
+        !tracked.has(aliased.place.identifier.id)
+      ) {
+        continue;
+      }
+      const effect = {kind: aliased.kind, from: aliased.place, into: input};
+      effects.push(effect);
+      if (
+        into === fn.returns.identifier.id &&
+        (aliased.kind === 'Assign' || aliased.kind === 'CreateFrom')
+      ) {
+        hasReturn = true;
+      }
+    }
+  }
+  // TODO: more precise return effect inference
+  if (!hasReturn) {
+    effects.unshift({
+      kind: 'Create',
+      into: fn.returns,
+      value:
+        fn.returnType.kind === 'Primitive'
+          ? ValueKind.Primitive
+          : ValueKind.Mutable,
+      reason: ValueReason.KnownReturnSignature,
+    });
+  }
+
+  return effects;
+}
+
+export enum MutationKind {
+  None = 0,
+  Conditional = 1,
+  Definite = 2,
+}
+
+type AliasingKind = 'Alias' | 'Capture' | 'CreateFrom' | 'Assign';
+function joinEffects(
+  effect1: AliasingKind,
+  effect2: AliasingKind,
+): AliasingKind {
+  if (effect1 === 'Capture' || effect2 === 'Capture') {
+    return 'Capture';
+  } else if (effect1 === 'Assign' || effect2 === 'Assign') {
+    return 'Assign';
+  } else {
+    return 'Alias';
+  }
+}

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

@@ -0,0 +1,629 @@
+/**
+ * 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 prettyFormat from 'pretty-format';
+import {CompilerError, SourceLocation} from '..';
+import {
+  BlockId,
+  Effect,
+  HIRFunction,
+  Identifier,
+  IdentifierId,
+  InstructionId,
+  makeInstructionId,
+  Place,
+} from '../HIR/HIR';
+import {
+  eachInstructionLValue,
+  eachInstructionValueOperand,
+  eachTerminalOperand,
+} from '../HIR/visitors';
+import {assertExhaustive, getOrInsertWith} from '../Utils/utils';
+import {printFunction} from '../HIR';
+import {printIdentifier, printPlace} from '../HIR/PrintHIR';
+import {MutationKind} from './InferMutationAliasingFunctionEffects';
+import {Result} from '../Utils/Result';
+
+const DEBUG = false;
+const VERBOSE = false;
+
+/**
+ * Infers mutable ranges for all values.
+ */
+export function inferMutationAliasingRanges(
+  fn: HIRFunction,
+  {isFunctionExpression}: {isFunctionExpression: boolean},
+): Result<void, CompilerError> {
+  if (VERBOSE) {
+    console.log();
+    console.log(printFunction(fn));
+  }
+  /**
+   * Part 1: Infer mutable ranges for values. We build an abstract model of
+   * values, the alias/capture edges between them, and the set of mutations.
+   * Edges and mutations are ordered, with mutations processed against the
+   * abstract model only after it is fully constructed by visiting all blocks
+   * _and_ connecting phis. Phis are considered ordered at the time of the
+   * phi node.
+   *
+   * This should (may?) mean that mutations are able to see the full state
+   * of the graph and mark all the appropriate identifiers as mutated at
+   * the correct point, accounting for both backward and forward edges.
+   * Ie a mutation of x accounts for both values that flowed into x,
+   * and values that x flowed into.
+   */
+  const state = new AliasingState();
+  type PendingPhiOperand = {from: Place; into: Place; index: number};
+  const pendingPhis = new Map<BlockId, Array<PendingPhiOperand>>();
+  const mutations: Array<{
+    index: number;
+    id: InstructionId;
+    transitive: boolean;
+    kind: MutationKind;
+    place: Place;
+  }> = [];
+
+  let index = 0;
+
+  const errors = new CompilerError();
+
+  for (const param of [...fn.params, ...fn.context, fn.returns]) {
+    const place = param.kind === 'Identifier' ? param : param.place;
+    state.create(place, {kind: 'Object'});
+  }
+  const seenBlocks = new Set<BlockId>();
+  for (const block of fn.body.blocks.values()) {
+    for (const phi of block.phis) {
+      state.create(phi.place, {kind: 'Phi'});
+      for (const [pred, operand] of phi.operands) {
+        if (!seenBlocks.has(pred)) {
+          // NOTE: annotation required to actually typecheck and not silently infer `any`
+          const blockPhis = getOrInsertWith<BlockId, Array<PendingPhiOperand>>(
+            pendingPhis,
+            pred,
+            () => [],
+          );
+          blockPhis.push({from: operand, into: phi.place, index: index++});
+        } else {
+          state.assign(index++, operand, phi.place);
+        }
+      }
+    }
+    seenBlocks.add(block.id);
+
+    for (const instr of block.instructions) {
+      if (
+        instr.value.kind === 'FunctionExpression' ||
+        instr.value.kind === 'ObjectMethod'
+      ) {
+        state.create(instr.lvalue, {
+          kind: 'Function',
+          function: instr.value.loweredFunc.func,
+        });
+      } else {
+        for (const lvalue of eachInstructionLValue(instr)) {
+          state.create(lvalue, {kind: 'Object'});
+        }
+      }
+
+      if (instr.effects == null) continue;
+      for (const effect of instr.effects) {
+        if (effect.kind === 'Create') {
+          state.create(effect.into, {kind: 'Object'});
+        } else if (effect.kind === 'CreateFunction') {
+          state.create(effect.into, {
+            kind: 'Function',
+            function: effect.function.loweredFunc.func,
+          });
+        } else if (effect.kind === 'CreateFrom') {
+          state.createFrom(index++, effect.from, effect.into);
+        } else if (effect.kind === 'Assign' || effect.kind === 'Alias') {
+          state.assign(index++, effect.from, effect.into);
+        } else if (effect.kind === 'Capture') {
+          state.capture(index++, effect.from, effect.into);
+        } else if (
+          effect.kind === 'MutateTransitive' ||
+          effect.kind === 'MutateTransitiveConditionally'
+        ) {
+          mutations.push({
+            index: index++,
+            id: instr.id,
+            transitive: true,
+            kind:
+              effect.kind === 'MutateTransitive'
+                ? MutationKind.Definite
+                : MutationKind.Conditional,
+            place: effect.value,
+          });
+        } else if (
+          effect.kind === 'Mutate' ||
+          effect.kind === 'MutateConditionally'
+        ) {
+          mutations.push({
+            index: index++,
+            id: instr.id,
+            transitive: false,
+            kind:
+              effect.kind === 'Mutate'
+                ? MutationKind.Definite
+                : MutationKind.Conditional,
+            place: effect.value,
+          });
+        } else if (
+          effect.kind === 'MutateFrozen' ||
+          effect.kind === 'MutateGlobal'
+        ) {
+          errors.push(effect.error);
+        }
+      }
+    }
+    const blockPhis = pendingPhis.get(block.id);
+    if (blockPhis != null) {
+      for (const {from, into, index} of blockPhis) {
+        state.assign(index, from, into);
+      }
+    }
+    if (block.terminal.kind === 'return') {
+      state.assign(index++, block.terminal.value, fn.returns);
+    }
+
+    if (
+      (block.terminal.kind === 'maybe-throw' ||
+        block.terminal.kind === 'return') &&
+      block.terminal.effects != null
+    ) {
+      for (const effect of block.terminal.effects) {
+        if (effect.kind === 'Alias') {
+          state.assign(index++, effect.from, effect.into);
+        } else {
+          CompilerError.invariant(effect.kind === 'Freeze', {
+            reason: `Unexpected '${effect.kind}' effect for MaybeThrow terminal`,
+            loc: block.terminal.loc,
+          });
+        }
+      }
+    }
+  }
+
+  if (VERBOSE) {
+    console.log(state.debug());
+    console.log(pretty(mutations));
+  }
+  for (const mutation of mutations) {
+    state.mutate(
+      mutation.index,
+      mutation.place.identifier,
+      makeInstructionId(mutation.id + 1),
+      mutation.transitive,
+      mutation.kind,
+      mutation.place.loc,
+      errors,
+    );
+  }
+  if (VERBOSE) {
+    console.log(state.debug());
+  }
+  fn.aliasingEffects ??= [];
+  for (const param of [...fn.context, ...fn.params]) {
+    const place = param.kind === 'Identifier' ? param : param.place;
+    const node = state.nodes.get(place.identifier);
+    if (node == null) {
+      continue;
+    }
+    let mutated = false;
+    if (node.local != null) {
+      if (node.local.kind === MutationKind.Conditional) {
+        mutated = true;
+        fn.aliasingEffects.push({
+          kind: 'MutateConditionally',
+          value: {...place, loc: node.local.loc},
+        });
+      } else if (node.local.kind === MutationKind.Definite) {
+        mutated = true;
+        fn.aliasingEffects.push({
+          kind: 'Mutate',
+          value: {...place, loc: node.local.loc},
+        });
+      }
+    }
+    if (node.transitive != null) {
+      if (node.transitive.kind === MutationKind.Conditional) {
+        mutated = true;
+        fn.aliasingEffects.push({
+          kind: 'MutateTransitiveConditionally',
+          value: {...place, loc: node.transitive.loc},
+        });
+      } else if (node.transitive.kind === MutationKind.Definite) {
+        mutated = true;
+        fn.aliasingEffects.push({
+          kind: 'MutateTransitive',
+          value: {...place, loc: node.transitive.loc},
+        });
+      }
+    }
+    if (mutated) {
+      place.effect = Effect.Capture;
+    }
+  }
+
+  /**
+   * Part 2
+   * Add legacy operand-specific effects based on instruction effects and mutable ranges.
+   * Also fixes up operand mutable ranges, making sure that start is non-zero if the value
+   * is mutated (depended on by later passes like InferReactiveScopeVariables which uses this
+   * to filter spurious mutations of globals, which we now guard against more precisely)
+   */
+  for (const block of fn.body.blocks.values()) {
+    for (const phi of block.phis) {
+      // TODO: we don't actually set these effects today!
+      phi.place.effect = Effect.Store;
+      const isPhiMutatedAfterCreation: boolean =
+        phi.place.identifier.mutableRange.end >
+        (block.instructions.at(0)?.id ?? block.terminal.id);
+      for (const operand of phi.operands.values()) {
+        operand.effect = isPhiMutatedAfterCreation
+          ? Effect.Capture
+          : Effect.Read;
+      }
+      if (
+        isPhiMutatedAfterCreation &&
+        phi.place.identifier.mutableRange.start === 0
+      ) {
+        /*
+         * TODO: ideally we'd construct a precise start range, but what really
+         * matters is that the phi's range appears mutable (end > start + 1)
+         * so we just set the start to the previous instruction before this block
+         */
+        const firstInstructionIdOfBlock =
+          block.instructions.at(0)?.id ?? block.terminal.id;
+        phi.place.identifier.mutableRange.start = makeInstructionId(
+          firstInstructionIdOfBlock - 1,
+        );
+      }
+    }
+    for (const instr of block.instructions) {
+      for (const lvalue of eachInstructionLValue(instr)) {
+        lvalue.effect = Effect.ConditionallyMutate;
+        if (lvalue.identifier.mutableRange.start === 0) {
+          lvalue.identifier.mutableRange.start = instr.id;
+        }
+        if (lvalue.identifier.mutableRange.end === 0) {
+          lvalue.identifier.mutableRange.end = makeInstructionId(
+            Math.max(instr.id + 1, lvalue.identifier.mutableRange.end),
+          );
+        }
+      }
+      for (const operand of eachInstructionValueOperand(instr.value)) {
+        operand.effect = Effect.Read;
+      }
+      if (instr.effects == null) {
+        continue;
+      }
+      const operandEffects = new Map<IdentifierId, Effect>();
+      for (const effect of instr.effects) {
+        switch (effect.kind) {
+          case 'Assign':
+          case 'Alias':
+          case 'Capture':
+          case 'CreateFrom': {
+            const isMutatedOrReassigned =
+              effect.into.identifier.mutableRange.end > instr.id;
+            if (isMutatedOrReassigned) {
+              operandEffects.set(effect.from.identifier.id, Effect.Capture);
+              operandEffects.set(effect.into.identifier.id, Effect.Store);
+            } else {
+              operandEffects.set(effect.from.identifier.id, Effect.Read);
+              operandEffects.set(effect.into.identifier.id, Effect.Store);
+            }
+            break;
+          }
+          case 'ImmutableCapture': {
+            operandEffects.set(effect.from.identifier.id, Effect.Read);
+            break;
+          }
+          case 'CreateFunction':
+          case 'Create': {
+            break;
+          }
+          case 'Mutate': {
+            operandEffects.set(effect.value.identifier.id, Effect.Store);
+            break;
+          }
+          case 'Apply': {
+            CompilerError.invariant(false, {
+              reason: `[AnalyzeFunctions] Expected Apply effects to be replaced with more precise effects`,
+              loc: effect.function.loc,
+            });
+          }
+          case 'MutateTransitive':
+          case 'MutateConditionally':
+          case 'MutateTransitiveConditionally': {
+            operandEffects.set(
+              effect.value.identifier.id,
+              Effect.ConditionallyMutate,
+            );
+            break;
+          }
+          case 'Freeze': {
+            operandEffects.set(effect.value.identifier.id, Effect.Freeze);
+            break;
+          }
+          case 'MutateFrozen':
+          case 'MutateGlobal': {
+            // no-op
+            break;
+          }
+          default: {
+            assertExhaustive(
+              effect,
+              `Unexpected effect kind ${(effect as any).kind}`,
+            );
+          }
+        }
+      }
+      for (const lvalue of eachInstructionLValue(instr)) {
+        const effect =
+          operandEffects.get(lvalue.identifier.id) ??
+          Effect.ConditionallyMutate;
+        lvalue.effect = effect;
+      }
+      for (const operand of eachInstructionValueOperand(instr.value)) {
+        if (
+          operand.identifier.mutableRange.end > instr.id &&
+          operand.identifier.mutableRange.start === 0
+        ) {
+          operand.identifier.mutableRange.start = instr.id;
+        }
+        const effect = operandEffects.get(operand.identifier.id) ?? Effect.Read;
+        operand.effect = effect;
+      }
+    }
+    if (block.terminal.kind === 'return') {
+      block.terminal.value.effect = isFunctionExpression
+        ? Effect.Read
+        : Effect.Freeze;
+    } else {
+      for (const operand of eachTerminalOperand(block.terminal)) {
+        operand.effect = Effect.Read;
+      }
+    }
+  }
+
+  if (VERBOSE) {
+    console.log(printFunction(fn));
+  }
+  return errors.asResult();
+}
+
+function appendFunctionErrors(errors: CompilerError, fn: HIRFunction): void {
+  for (const effect of fn.aliasingEffects ?? []) {
+    switch (effect.kind) {
+      case 'MutateFrozen':
+      case 'MutateGlobal': {
+        errors.push(effect.error);
+        break;
+      }
+    }
+  }
+}
+
+type Node = {
+  id: Identifier;
+  createdFrom: Map<Identifier, number>;
+  captures: Map<Identifier, number>;
+  aliases: Map<Identifier, number>;
+  edges: Array<{index: number; node: Identifier; kind: 'capture' | 'alias'}>;
+  transitive: {kind: MutationKind; loc: SourceLocation} | null;
+  local: {kind: MutationKind; loc: SourceLocation} | null;
+  value:
+    | {kind: 'Object'}
+    | {kind: 'Phi'}
+    | {kind: 'Function'; function: HIRFunction};
+};
+class AliasingState {
+  nodes: Map<Identifier, Node> = new Map();
+
+  create(place: Place, value: Node['value']): void {
+    this.nodes.set(place.identifier, {
+      id: place.identifier,
+      createdFrom: new Map(),
+      captures: new Map(),
+      aliases: new Map(),
+      edges: [],
+      transitive: null,
+      local: null,
+      value,
+    });
+  }
+
+  createFrom(index: number, from: Place, into: Place): void {
+    this.create(into, {kind: 'Object'});
+    const fromNode = this.nodes.get(from.identifier);
+    const toNode = this.nodes.get(into.identifier);
+    if (fromNode == null || toNode == null) {
+      if (VERBOSE) {
+        console.log(
+          `skip: createFrom ${printPlace(from)}${!!fromNode} -> ${printPlace(into)}${!!toNode}`,
+        );
+      }
+      return;
+    }
+    fromNode.edges.push({index, node: into.identifier, kind: 'alias'});
+    if (!toNode.createdFrom.has(from.identifier)) {
+      toNode.createdFrom.set(from.identifier, index);
+    }
+  }
+
+  capture(index: number, from: Place, into: Place): void {
+    const fromNode = this.nodes.get(from.identifier);
+    const toNode = this.nodes.get(into.identifier);
+    if (fromNode == null || toNode == null) {
+      if (VERBOSE) {
+        console.log(
+          `skip: capture ${printPlace(from)}${!!fromNode} -> ${printPlace(into)}${!!toNode}`,
+        );
+      }
+      return;
+    }
+    fromNode.edges.push({index, node: into.identifier, kind: 'capture'});
+    if (!toNode.captures.has(from.identifier)) {
+      toNode.captures.set(from.identifier, index);
+    }
+  }
+
+  assign(index: number, from: Place, into: Place): void {
+    const fromNode = this.nodes.get(from.identifier);
+    const toNode = this.nodes.get(into.identifier);
+    if (fromNode == null || toNode == null) {
+      if (VERBOSE) {
+        console.log(
+          `skip: assign ${printPlace(from)}${!!fromNode} -> ${printPlace(into)}${!!toNode}`,
+        );
+      }
+      return;
+    }
+    fromNode.edges.push({index, node: into.identifier, kind: 'alias'});
+    if (!toNode.aliases.has(from.identifier)) {
+      toNode.aliases.set(from.identifier, index);
+    }
+  }
+
+  mutate(
+    index: number,
+    start: Identifier,
+    end: InstructionId,
+    transitive: boolean,
+    kind: MutationKind,
+    loc: SourceLocation,
+    errors: CompilerError,
+  ): void {
+    const seen = new Set<Identifier>();
+    const queue: Array<{
+      place: Identifier;
+      transitive: boolean;
+      direction: 'backwards' | 'forwards';
+    }> = [{place: start, transitive, direction: 'backwards'}];
+    while (queue.length !== 0) {
+      const {place: current, transitive, direction} = queue.pop()!;
+      if (seen.has(current)) {
+        continue;
+      }
+      seen.add(current);
+      const node = this.nodes.get(current);
+      if (node == null) {
+        if (DEBUG) {
+          console.log(
+            `no node! ${printIdentifier(start)} for identifier ${printIdentifier(current)}`,
+          );
+        }
+        continue;
+      }
+      if (DEBUG) {
+        console.log(
+          `[${end}] mutate index=${index} ${printIdentifier(start)}: ${printIdentifier(node.id)}`,
+        );
+      }
+      node.id.mutableRange.end = makeInstructionId(
+        Math.max(node.id.mutableRange.end, end),
+      );
+      if (
+        node.value.kind === 'Function' &&
+        node.transitive == null &&
+        node.local == null
+      ) {
+        appendFunctionErrors(errors, node.value.function);
+      }
+      if (transitive) {
+        if (node.transitive == null || node.transitive.kind < kind) {
+          node.transitive = {kind, loc};
+        }
+      } else {
+        if (node.local == null || node.local.kind < kind) {
+          node.local = {kind, loc};
+        }
+      }
+      /**
+       * all mutations affect "forward" edges by the rules:
+       * - Capture a -> b, mutate(a) => mutate(b)
+       * - Alias a -> b, mutate(a) => mutate(b)
+       */
+      for (const edge of node.edges) {
+        if (edge.index >= index) {
+          break;
+        }
+        queue.push({place: edge.node, transitive, direction: 'forwards'});
+      }
+      for (const [alias, when] of node.createdFrom) {
+        if (when >= index) {
+          continue;
+        }
+        queue.push({place: alias, transitive: true, direction: 'backwards'});
+      }
+      if (direction === 'backwards' || node.value.kind !== 'Phi') {
+        /**
+         * all mutations affect backward alias edges by the rules:
+         * - Alias a -> b, mutate(b) => mutate(a)
+         * - Alias a -> b, mutateTransitive(b) => mutate(a)
+         *
+         * However, if we reached a phi because one of its inputs was mutated
+         * (and we're advancing "forwards" through that node's edges), then
+         * we know we've already processed the mutation at its source. The
+         * phi's other inputs can't be affected.
+         */
+        for (const [alias, when] of node.aliases) {
+          if (when >= index) {
+            continue;
+          }
+          queue.push({place: alias, transitive, direction: 'backwards'});
+        }
+      }
+      /**
+       * but only transitive mutations affect captures
+       */
+      if (transitive) {
+        for (const [capture, when] of node.captures) {
+          if (when >= index) {
+            continue;
+          }
+          queue.push({place: capture, transitive, direction: 'backwards'});
+        }
+      }
+    }
+    if (DEBUG) {
+      const nodes = new Map();
+      for (const id of seen) {
+        const node = this.nodes.get(id);
+        nodes.set(id.id, node);
+      }
+      console.log(pretty(nodes));
+    }
+  }
+
+  debug(): string {
+    return pretty(this.nodes);
+  }
+}
+
+export function pretty(v: any): string {
+  return prettyFormat(v, {
+    plugins: [
+      {
+        test: v =>
+          v !== null && typeof v === 'object' && v.kind === 'Identifier',
+        serialize: v => printPlace(v),
+      },
+      {
+        test: v =>
+          v !== null &&
+          typeof v === 'object' &&
+          typeof v.declarationId === 'number',
+        serialize: v =>
+          `${printIdentifier(v)}:${v.mutableRange.start}:${v.mutableRange.end}`,
+      },
+    ],
+  });
+}

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

@@ -31,13 +31,13 @@ import {
   isArrayType,
   isMapType,
   isMutableEffect,
-  isObjectType,
   isSetType,
+  isObjectType,
 } from '../HIR/HIR';
 import {FunctionSignature} from '../HIR/ObjectShape';
 import {
   printIdentifier,
-  printMixedHIR,
+  printInstructionValue,
   printPlace,
   printSourceLocation,
 } from '../HIR/PrintHIR';
@@ -48,7 +48,7 @@ import {
   eachTerminalOperand,
   eachTerminalSuccessor,
 } from '../HIR/visitors';
-import {assertExhaustive} from '../Utils/utils';
+import {assertExhaustive, retainWhere, Set_isSuperset} from '../Utils/utils';
 import {
   inferTerminalFunctionEffects,
   inferInstructionFunctionEffects,
@@ -521,7 +521,7 @@ class InferenceState {
          *   `expected valueKind to be 'Mutable' but found to be \`${valueKind}\``
          * );
          */
-        effect = isObjectType(place.identifier) ? Effect.Store : Effect.Mutate;
+        effect = Effect.Store;
         break;
       }
       case Effect.Capture: {
@@ -669,7 +669,10 @@ class InferenceState {
     }
     for (const [value, kind] of this.#values) {
       const id = identify(value);
-      result.values[id] = {kind, value: printMixedHIR(value)};
+      result.values[id] = {
+        abstract: this.debugAbstractValue(kind),
+        value: printInstructionValue(value),
+      };
     }
     for (const [variable, values] of this.#variables) {
       result.variables[`$${variable}`] = [...values].map(identify);
@@ -677,6 +680,14 @@ class InferenceState {
     return result;
   }
 
+  debugAbstractValue(value: AbstractValue): any {
+    return {
+      kind: value.kind,
+      context: [...value.context].map(printPlace),
+      reason: [...value.reason],
+    };
+  }
+
   inferPhi(phi: Phi): void {
     const values: Set<InstructionValue> = new Set();
     for (const [_, operand] of phi.operands) {
@@ -779,7 +790,7 @@ function inferParam(
  * │         Mutable          │───┘
  * └──────────────────────────┘
  */
-function mergeValues(a: ValueKind, b: ValueKind): ValueKind {
+export function mergeValueKinds(a: ValueKind, b: ValueKind): ValueKind {
   if (a === b) {
     return a;
   } else if (a === ValueKind.MaybeFrozen || b === ValueKind.MaybeFrozen) {
@@ -821,28 +832,16 @@ function mergeValues(a: ValueKind, b: ValueKind): ValueKind {
   }
 }
 
-/**
- * @returns `true` if `a` is a superset of `b`.
- */
-function isSuperset<T>(a: ReadonlySet<T>, b: ReadonlySet<T>): boolean {
-  for (const v of b) {
-    if (!a.has(v)) {
-      return false;
-    }
-  }
-  return true;
-}
-
 function mergeAbstractValues(
   a: AbstractValue,
   b: AbstractValue,
 ): AbstractValue {
-  const kind = mergeValues(a.kind, b.kind);
+  const kind = mergeValueKinds(a.kind, b.kind);
   if (
     kind === a.kind &&
     kind === b.kind &&
-    isSuperset(a.reason, b.reason) &&
-    isSuperset(a.context, b.context)
+    Set_isSuperset(a.reason, b.reason) &&
+    Set_isSuperset(a.context, b.context)
   ) {
     return a;
   }
@@ -902,19 +901,11 @@ function inferBlock(
         break;
       }
       case 'ArrayExpression': {
-        const contextRefOperands = getContextRefOperand(state, instrValue);
-        const valueKind: AbstractValue =
-          contextRefOperands.length > 0
-            ? {
-                kind: ValueKind.Context,
-                reason: new Set([ValueReason.Other]),
-                context: new Set(contextRefOperands),
-              }
-            : {
-                kind: ValueKind.Mutable,
-                reason: new Set([ValueReason.Other]),
-                context: new Set(),
-              };
+        const valueKind: AbstractValue = {
+          kind: ValueKind.Mutable,
+          reason: new Set([ValueReason.Other]),
+          context: new Set(),
+        };
 
         for (const element of instrValue.elements) {
           if (element.kind === 'Spread') {
@@ -935,6 +926,7 @@ function inferBlock(
             let _: 'Hole' = element.kind;
           }
         }
+
         state.initialize(instrValue, valueKind);
         state.define(instr.lvalue, instrValue);
         instr.lvalue.effect = Effect.Store;
@@ -954,19 +946,11 @@ function inferBlock(
         break;
       }
       case 'ObjectExpression': {
-        const contextRefOperands = getContextRefOperand(state, instrValue);
-        const valueKind: AbstractValue =
-          contextRefOperands.length > 0
-            ? {
-                kind: ValueKind.Context,
-                reason: new Set([ValueReason.Other]),
-                context: new Set(contextRefOperands),
-              }
-            : {
-                kind: ValueKind.Mutable,
-                reason: new Set([ValueReason.Other]),
-                context: new Set(),
-              };
+        const valueKind: AbstractValue = {
+          kind: ValueKind.Mutable,
+          reason: new Set([ValueReason.Other]),
+          context: new Set(),
+        };
 
         for (const property of instrValue.properties) {
           switch (property.kind) {
@@ -1190,6 +1174,35 @@ function inferBlock(
           );
           hasMutableOperand ||= isMutableEffect(operand.effect, operand.loc);
         }
+
+        /*
+         * Filter CaptureEffects to remove values that are immutable and don't
+         * need to be tracked for aliasing
+         */
+        const effects = instrValue.loweredFunc.func.effects;
+        if (effects != null && effects.length !== 0) {
+          retainWhere(effects, effect => {
+            if (effect.kind !== 'CaptureEffect') {
+              return true;
+            }
+            const places: Set<Place> = new Set();
+            for (const place of effect.places) {
+              const kind = state.kind(place);
+              if (
+                kind.kind === ValueKind.Context ||
+                kind.kind === ValueKind.MaybeFrozen ||
+                kind.kind === ValueKind.Mutable
+              ) {
+                places.add(place);
+              }
+            }
+            if (places.size === 0) {
+              return false;
+            }
+            effect.places = places;
+            return true;
+          });
+        }
         /*
          * If a closure did not capture any mutable values, then we can consider it to be
          * frozen, which allows it to be independently memoized.
@@ -1280,20 +1293,18 @@ function inferBlock(
         break;
       }
       case 'PropertyStore': {
-        const effect =
-          state.kind(instrValue.object).kind === ValueKind.Context
-            ? Effect.ConditionallyMutate
-            : Effect.Capture;
         state.referenceAndRecordEffects(
           freezeActions,
           instrValue.value,
-          effect,
+          Effect.Capture,
           ValueReason.Other,
         );
         state.referenceAndRecordEffects(
           freezeActions,
           instrValue.object,
-          Effect.Store,
+          isObjectType(instrValue.object.identifier)
+            ? Effect.Store
+            : Effect.Mutate,
           ValueReason.Other,
         );
 
@@ -1320,25 +1331,21 @@ function inferBlock(
         state.referenceAndRecordEffects(
           freezeActions,
           instrValue.object,
-          Effect.Read,
+          Effect.Capture,
           ValueReason.Other,
         );
         const lvalue = instr.lvalue;
-        lvalue.effect = Effect.ConditionallyMutate;
+        lvalue.effect = Effect.Store;
         state.initialize(instrValue, state.kind(instrValue.object));
         state.define(lvalue, instrValue);
         continuation = {kind: 'funeffects'};
         break;
       }
       case 'ComputedStore': {
-        const effect =
-          state.kind(instrValue.object).kind === ValueKind.Context
-            ? Effect.ConditionallyMutate
-            : Effect.Capture;
         state.referenceAndRecordEffects(
           freezeActions,
           instrValue.value,
-          effect,
+          Effect.Capture,
           ValueReason.Other,
         );
         state.referenceAndRecordEffects(
@@ -1350,7 +1357,9 @@ function inferBlock(
         state.referenceAndRecordEffects(
           freezeActions,
           instrValue.object,
-          Effect.Store,
+          isObjectType(instrValue.object.identifier)
+            ? Effect.Store
+            : Effect.Mutate,
           ValueReason.Other,
         );
 
@@ -1387,7 +1396,7 @@ function inferBlock(
         state.referenceAndRecordEffects(
           freezeActions,
           instrValue.object,
-          Effect.Read,
+          Effect.Capture,
           ValueReason.Other,
         );
         state.referenceAndRecordEffects(
@@ -1397,7 +1406,7 @@ function inferBlock(
           ValueReason.Other,
         );
         const lvalue = instr.lvalue;
-        lvalue.effect = Effect.ConditionallyMutate;
+        lvalue.effect = Effect.Store;
         state.initialize(instrValue, state.kind(instrValue.object));
         state.define(lvalue, instrValue);
         continuation = {kind: 'funeffects'};
@@ -1811,7 +1820,9 @@ function inferBlock(
         state.isDefined(operand) &&
         ((operand.identifier.type.kind === 'Function' &&
           state.isFunctionExpression) ||
-          state.kind(operand).kind === ValueKind.Context)
+          state.kind(operand).kind === ValueKind.Context ||
+          (state.kind(operand).kind === ValueKind.Mutable &&
+            state.isFunctionExpression))
       ) {
         /**
          * Returned values should only be typed as 'frozen' if they are both (1)
@@ -1838,22 +1849,6 @@ function inferBlock(
   );
 }
 
-function getContextRefOperand(
-  state: InferenceState,
-  instrValue: InstructionValue,
-): Array<Place> {
-  const result = [];
-  for (const place of eachInstructionValueOperand(instrValue)) {
-    if (
-      state.isDefined(place) &&
-      state.kind(place).kind === ValueKind.Context
-    ) {
-      result.push(place);
-    }
-  }
-  return result;
-}
-
 export function getFunctionCallSignature(
   env: Environment,
   type: Type,

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

@@ -235,6 +235,7 @@ function rewriteBlock(
       type: null,
       loc: terminal.loc,
     },
+    effects: null,
   });
   block.terminal = {
     kind: 'goto',
@@ -263,5 +264,6 @@ function declareTemporary(
       type: null,
       loc: result.loc,
     },
+    effects: null,
   });
 }

compiler/packages/babel-plugin-react-compiler/src/Optimization/InlineJsxTransform.ts

@@ -27,6 +27,7 @@ import {
   Place,
   promoteTemporary,
   SpreadPattern,
+  todoPopulateAliasingEffects,
 } from '../HIR';
 import {
   createTemporaryPlace,
@@ -151,6 +152,7 @@ export function inlineJsxTransform(
               type: null,
               loc: instr.value.loc,
             },
+            effects: todoPopulateAliasingEffects(),
             loc: instr.loc,
           };
           currentBlockInstructions.push(varInstruction);
@@ -167,6 +169,7 @@ export function inlineJsxTransform(
               },
               loc: instr.value.loc,
             },
+            effects: todoPopulateAliasingEffects(),
             loc: instr.loc,
           };
           currentBlockInstructions.push(devGlobalInstruction);
@@ -220,6 +223,7 @@ export function inlineJsxTransform(
               type: null,
               loc: instr.value.loc,
             },
+            effects: todoPopulateAliasingEffects(),
             loc: instr.loc,
           };
           thenBlockInstructions.push(reassignElseInstruction);
@@ -292,6 +296,7 @@ export function inlineJsxTransform(
               ],
               loc: instr.value.loc,
             },
+            effects: todoPopulateAliasingEffects(),
             loc: instr.loc,
           };
           elseBlockInstructions.push(reactElementInstruction);
@@ -309,6 +314,7 @@ export function inlineJsxTransform(
               type: null,
               loc: instr.value.loc,
             },
+            effects: todoPopulateAliasingEffects(),
             loc: instr.loc,
           };
           elseBlockInstructions.push(reassignConditionalInstruction);
@@ -436,6 +442,7 @@ function createSymbolProperty(
       binding: {kind: 'Global', name: 'Symbol'},
       loc: instr.value.loc,
     },
+    effects: todoPopulateAliasingEffects(),
     loc: instr.loc,
   };
   nextInstructions.push(symbolInstruction);
@@ -450,6 +457,7 @@ function createSymbolProperty(
       property: makePropertyLiteral('for'),
       loc: instr.value.loc,
     },
+    effects: todoPopulateAliasingEffects(),
     loc: instr.loc,
   };
   nextInstructions.push(symbolForInstruction);
@@ -463,6 +471,7 @@ function createSymbolProperty(
       value: symbolName,
       loc: instr.value.loc,
     },
+    effects: todoPopulateAliasingEffects(),
     loc: instr.loc,
   };
   nextInstructions.push(symbolValueInstruction);
@@ -478,6 +487,7 @@ function createSymbolProperty(
       args: [symbolValueInstruction.lvalue],
       loc: instr.value.loc,
     },
+    effects: todoPopulateAliasingEffects(),
     loc: instr.loc,
   };
   const $$typeofProperty: ObjectProperty = {
@@ -508,6 +518,7 @@ function createTagProperty(
           value: componentTag.name,
           loc: instr.value.loc,
         },
+        effects: todoPopulateAliasingEffects(),
         loc: instr.loc,
       };
       tagProperty = {
@@ -634,6 +645,7 @@ function createPropsProperties(
           elements: [...children],
           loc: instr.value.loc,
         },
+        effects: todoPopulateAliasingEffects(),
         loc: instr.loc,
       };
       nextInstructions.push(childrenPropInstruction);
@@ -657,6 +669,7 @@ function createPropsProperties(
         value: null,
         loc: instr.value.loc,
       },
+      effects: todoPopulateAliasingEffects(),
       loc: instr.loc,
     };
     refProperty = {
@@ -678,6 +691,7 @@ function createPropsProperties(
         value: null,
         loc: instr.value.loc,
       },
+      effects: todoPopulateAliasingEffects(),
       loc: instr.loc,
     };
     keyProperty = {
@@ -711,6 +725,7 @@ function createPropsProperties(
         properties: props,
         loc: instr.value.loc,
       },
+      effects: todoPopulateAliasingEffects(),
       loc: instr.loc,
     };
     propsProperty = {

compiler/packages/babel-plugin-react-compiler/src/Optimization/LowerContextAccess.ts

@@ -29,6 +29,7 @@ import {
   markInstructionIds,
   promoteTemporary,
   reversePostorderBlocks,
+  todoPopulateAliasingEffects,
 } from '../HIR';
 import {createTemporaryPlace} from '../HIR/HIRBuilder';
 import {enterSSA} from '../SSA';
@@ -146,6 +147,7 @@ function emitLoadLoweredContextCallee(
     id: makeInstructionId(0),
     loc: GeneratedSource,
     lvalue: createTemporaryPlace(env, GeneratedSource),
+    effects: todoPopulateAliasingEffects(),
     value: loadGlobal,
   };
 }
@@ -192,6 +194,7 @@ function emitPropertyLoad(
     lvalue: object,
     value: loadObj,
     id: makeInstructionId(0),
+    effects: todoPopulateAliasingEffects(),
     loc: GeneratedSource,
   };
 
@@ -206,6 +209,7 @@ function emitPropertyLoad(
     lvalue: element,
     value: loadProp,
     id: makeInstructionId(0),
+    effects: todoPopulateAliasingEffects(),
     loc: GeneratedSource,
   };
   return {
@@ -237,6 +241,7 @@ function emitSelectorFn(env: Environment, keys: Array<string>): Instruction {
       kind: 'return',
       loc: GeneratedSource,
       value: arrayInstr.lvalue,
+      effects: null,
     },
     preds: new Set(),
     phis: new Set(),
@@ -250,6 +255,7 @@ function emitSelectorFn(env: Environment, keys: Array<string>): Instruction {
     params: [obj],
     returnTypeAnnotation: null,
     returnType: makeType(),
+    returns: createTemporaryPlace(env, GeneratedSource),
     context: [],
     effects: null,
     body: {
@@ -278,6 +284,7 @@ function emitSelectorFn(env: Environment, keys: Array<string>): Instruction {
       loc: GeneratedSource,
     },
     lvalue: createTemporaryPlace(env, GeneratedSource),
+    effects: todoPopulateAliasingEffects(),
     loc: GeneratedSource,
   };
   return fnInstr;
@@ -294,6 +301,7 @@ function emitArrayInstr(elements: Array<Place>, env: Environment): Instruction {
     id: makeInstructionId(0),
     value: array,
     lvalue: arrayLvalue,
+    effects: todoPopulateAliasingEffects(),
     loc: GeneratedSource,
   };
   return arrayInstr;

compiler/packages/babel-plugin-react-compiler/src/Optimization/OutlineJsx.ts

@@ -26,6 +26,7 @@ import {
   Place,
   promoteTemporary,
   promoteTemporaryJsxTag,
+  todoPopulateAliasingEffects,
 } from '../HIR/HIR';
 import {createTemporaryPlace} from '../HIR/HIRBuilder';
 import {printIdentifier} from '../HIR/PrintHIR';
@@ -297,6 +298,7 @@ function emitOutlinedJsx(
       },
       loc: GeneratedSource,
     },
+    effects: null,
   };
   promoteTemporaryJsxTag(loadJsx.lvalue.identifier);
   const jsxExpr: Instruction = {
@@ -312,6 +314,7 @@ function emitOutlinedJsx(
       openingLoc: GeneratedSource,
       closingLoc: GeneratedSource,
     },
+    effects: todoPopulateAliasingEffects(),
   };
 
   return [loadJsx, jsxExpr];
@@ -353,6 +356,7 @@ function emitOutlinedFn(
       kind: 'return',
       loc: GeneratedSource,
       value: instructions.at(-1)!.lvalue,
+      effects: null,
     },
     preds: new Set(),
     phis: new Set(),
@@ -366,6 +370,7 @@ function emitOutlinedFn(
     params: [propsObj],
     returnTypeAnnotation: null,
     returnType: makeType(),
+    returns: createTemporaryPlace(env, GeneratedSource),
     context: [],
     effects: null,
     body: {
@@ -517,6 +522,7 @@ function emitDestructureProps(
       loc: GeneratedSource,
       value: propsObj,
     },
+    effects: todoPopulateAliasingEffects(),
   };
   return destructurePropsInstr;
 }

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

@@ -44,7 +44,7 @@ import {
   getHookKind,
   makeIdentifierName,
 } from '../HIR/HIR';
-import {printIdentifier, printPlace} from '../HIR/PrintHIR';
+import {printIdentifier, printInstruction, printPlace} from '../HIR/PrintHIR';
 import {eachPatternOperand} from '../HIR/visitors';
 import {Err, Ok, Result} from '../Utils/Result';
 import {GuardKind} from '../Utils/RuntimeDiagnosticConstants';
@@ -1183,7 +1183,7 @@ function codegenTerminal(
               ? codegenPlaceToExpression(cx, case_.test)
               : null;
           const block = codegenBlock(cx, case_.block!);
-          return t.switchCase(test, [block]);
+          return t.switchCase(test, block.body.length === 0 ? [] : [block]);
         }),
       );
     }
@@ -1310,7 +1310,7 @@ function codegenInstructionNullable(
         });
         CompilerError.invariant(value?.type === 'FunctionExpression', {
           reason: 'Expected a function as a function declaration value',
-          description: null,
+          description: `Got ${value == null ? String(value) : value.type} at ${printInstruction(instr)}`,
           loc: instr.value.loc,
           suggestions: null,
         });

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

@@ -31,6 +31,7 @@ import {
   NonLocalImportSpecifier,
   Place,
   promoteTemporary,
+  todoPopulateAliasingEffects,
 } from '../HIR';
 import {createTemporaryPlace, markInstructionIds} from '../HIR/HIRBuilder';
 import {getOrInsertWith} from '../Utils/utils';
@@ -436,6 +437,7 @@ function makeLoadUseFireInstruction(
     value: instrValue,
     lvalue: {...useFirePlace},
     loc: GeneratedSource,
+    effects: todoPopulateAliasingEffects(),
   };
 }
 
@@ -460,6 +462,7 @@ function makeLoadFireCalleeInstruction(
     },
     lvalue: {...loadedFireCallee},
     loc: GeneratedSource,
+    effects: todoPopulateAliasingEffects(),
   };
 }
 
@@ -483,6 +486,7 @@ function makeCallUseFireInstruction(
     value: useFireCall,
     lvalue: {...useFireCallResultPlace},
     loc: GeneratedSource,
+    effects: todoPopulateAliasingEffects(),
   };
 }
 
@@ -511,6 +515,7 @@ function makeStoreUseFireInstruction(
     },
     lvalue: fireFunctionBindingLValuePlace,
     loc: GeneratedSource,
+    effects: todoPopulateAliasingEffects(),
   };
 }
 

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

@@ -121,6 +121,21 @@ export function Set_intersect<T>(sets: Array<ReadonlySet<T>>): Set<T> {
   return result;
 }
 
+/**
+ * @returns `true` if `a` is a superset of `b`.
+ */
+export function Set_isSuperset<T>(
+  a: ReadonlySet<T>,
+  b: ReadonlySet<T>,
+): boolean {
+  for (const v of b) {
+    if (!a.has(v)) {
+      return false;
+    }
+  }
+  return true;
+}
+
 export function Iterable_some<T>(
   iter: Iterable<T>,
   pred: (item: T) => boolean,
@@ -133,6 +148,19 @@ export function Iterable_some<T>(
   return false;
 }
 
+export function Iterable_filter<T>(
+  iter: Iterable<T>,
+  pred: (item: T) => boolean,
+): Array<T> {
+  const result: Array<T> = [];
+  for (const item of iter) {
+    if (pred(item)) {
+      result.push(item);
+    }
+  }
+  return result;
+}
+
 export function nonNull<T extends NonNullable<U>, U>(
   value: T | null | undefined,
 ): value is T {

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

@@ -112,6 +112,31 @@ export function validateNoFreezingKnownMutableFunctions(
           );
           if (knownMutation && knownMutation.kind === 'ContextMutation') {
             contextMutationEffects.set(lvalue.identifier.id, knownMutation);
+          } else if (
+            fn.env.config.enableNewMutationAliasingModel &&
+            value.loweredFunc.func.aliasingEffects != null
+          ) {
+            const context = new Set(
+              value.loweredFunc.func.context.map(p => p.identifier.id),
+            );
+            effects: for (const effect of value.loweredFunc.func
+              .aliasingEffects) {
+              switch (effect.kind) {
+                case 'Mutate':
+                case 'MutateTransitive': {
+                  if (context.has(effect.value.identifier.id)) {
+                    contextMutationEffects.set(lvalue.identifier.id, {
+                      kind: 'ContextMutation',
+                      effect: Effect.Mutate,
+                      loc: effect.value.loc,
+                      places: new Set([effect.value]),
+                    });
+                    break effects;
+                  }
+                  break;
+                }
+              }
+            }
           }
           break;
         }

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/aliased-capture-aliased-mutate.expect.md

@@ -0,0 +1,71 @@
+
+## Input
+
+```javascript
+// @flow @enableTransitivelyFreezeFunctionExpressions:false
+import {arrayPush, setPropertyByKey, Stringify} from 'shared-runtime';
+
+function useFoo({a, b}: {a: number, b: number}) {
+  const x = [];
+  const y = {value: a};
+
+  arrayPush(x, y); // x and y co-mutate
+  const y_alias = y;
+  const cb = () => y_alias.value;
+  setPropertyByKey(x[0], 'value', b); // might overwrite y.value
+  return <Stringify cb={cb} shouldInvokeFns={true} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{a: 2, b: 10}],
+  sequentialRenders: [
+    {a: 2, b: 10},
+    {a: 2, b: 11},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { arrayPush, setPropertyByKey, Stringify } from "shared-runtime";
+
+function useFoo(t0) {
+  const $ = _c(3);
+  const { a, b } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b) {
+    const x = [];
+    const y = { value: a };
+
+    arrayPush(x, y);
+    const y_alias = y;
+    const cb = () => y_alias.value;
+    setPropertyByKey(x[0], "value", b);
+    t1 = <Stringify cb={cb} shouldInvokeFns={true} />;
+    $[0] = a;
+    $[1] = b;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{ a: 2, b: 10 }],
+  sequentialRenders: [
+    { a: 2, b: 10 },
+    { a: 2, b: 11 },
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
+<div>{"cb":{"kind":"Function","result":11},"shouldInvokeFns":true}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/aliased-capture-aliased-mutate.js

@@ -0,0 +1,22 @@
+// @flow @enableTransitivelyFreezeFunctionExpressions:false
+import {arrayPush, setPropertyByKey, Stringify} from 'shared-runtime';
+
+function useFoo({a, b}: {a: number, b: number}) {
+  const x = [];
+  const y = {value: a};
+
+  arrayPush(x, y); // x and y co-mutate
+  const y_alias = y;
+  const cb = () => y_alias.value;
+  setPropertyByKey(x[0], 'value', b); // might overwrite y.value
+  return <Stringify cb={cb} shouldInvokeFns={true} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{a: 2, b: 10}],
+  sequentialRenders: [
+    {a: 2, b: 10},
+    {a: 2, b: 11},
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/aliased-capture-mutate.expect.md

@@ -5,19 +5,6 @@
 // @flow @enableTransitivelyFreezeFunctionExpressions:false
 import {setPropertyByKey, Stringify} from 'shared-runtime';
 
-/**
- * Variation of bug in `bug-aliased-capture-aliased-mutate`
- * Found differences in evaluator results
- * Non-forget (expected):
- *   (kind: ok)
- *   <div>{"cb":{"kind":"Function","result":2},"shouldInvokeFns":true}</div>
- *   <div>{"cb":{"kind":"Function","result":3},"shouldInvokeFns":true}</div>
- * Forget:
- *   (kind: ok)
- *   <div>{"cb":{"kind":"Function","result":2},"shouldInvokeFns":true}</div>
- *   <div>{"cb":{"kind":"Function","result":2},"shouldInvokeFns":true}</div>
- */
-
 function useFoo({a}: {a: number, b: number}) {
   const arr = [];
   const obj = {value: a};
@@ -46,7 +33,7 @@ import { c as _c } from "react/compiler-runtime";
 import { setPropertyByKey, Stringify } from "shared-runtime";
 
 function useFoo(t0) {
-  const $ = _c(4);
+  const $ = _c(2);
   const { a } = t0;
   let t1;
   if ($[0] !== a) {
@@ -55,15 +42,7 @@ function useFoo(t0) {
 
     setPropertyByKey(obj, "arr", arr);
     const obj_alias = obj;
-    let t2;
-    if ($[2] !== obj_alias.arr.length) {
-      t2 = () => obj_alias.arr.length;
-      $[2] = obj_alias.arr.length;
-      $[3] = t2;
-    } else {
-      t2 = $[3];
-    }
-    const cb = t2;
+    const cb = () => obj_alias.arr.length;
     for (let i = 0; i < a; i++) {
       arr.push(i);
     }
@@ -84,4 +63,7 @@ export const FIXTURE_ENTRYPOINT = {
 };
 
 ```
-      
+      
+### Eval output
+(kind: ok) <div>{"cb":{"kind":"Function","result":2},"shouldInvokeFns":true}</div>
+<div>{"cb":{"kind":"Function","result":3},"shouldInvokeFns":true}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/aliased-capture-mutate.js

@@ -1,19 +1,6 @@
 // @flow @enableTransitivelyFreezeFunctionExpressions:false
 import {setPropertyByKey, Stringify} from 'shared-runtime';
 
-/**
- * Variation of bug in `bug-aliased-capture-aliased-mutate`
- * Found differences in evaluator results
- * Non-forget (expected):
- *   (kind: ok)
- *   <div>{"cb":{"kind":"Function","result":2},"shouldInvokeFns":true}</div>
- *   <div>{"cb":{"kind":"Function","result":3},"shouldInvokeFns":true}</div>
- * Forget:
- *   (kind: ok)
- *   <div>{"cb":{"kind":"Function","result":2},"shouldInvokeFns":true}</div>
- *   <div>{"cb":{"kind":"Function","result":2},"shouldInvokeFns":true}</div>
- */
-
 function useFoo({a}: {a: number, b: number}) {
   const arr = [];
   const obj = {value: a};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/array-map-captures-receiver-noAlias.expect.md

@@ -23,34 +23,18 @@ export const FIXTURE_ENTRYPOINT = {
 ```javascript
 import { c as _c } from "react/compiler-runtime";
 function Component(props) {
-  const $ = _c(6);
+  const $ = _c(2);
   let t0;
   if ($[0] !== props.a) {
-    t0 = { a: props.a };
+    const item = { a: props.a };
+    const items = [item];
+    t0 = items.map(_temp);
     $[0] = props.a;
     $[1] = t0;
   } else {
     t0 = $[1];
   }
-  const item = t0;
-  let t1;
-  if ($[2] !== item) {
-    t1 = [item];
-    $[2] = item;
-    $[3] = t1;
-  } else {
-    t1 = $[3];
-  }
-  const items = t1;
-  let t2;
-  if ($[4] !== items) {
-    t2 = items.map(_temp);
-    $[4] = items;
-    $[5] = t2;
-  } else {
-    t2 = $[5];
-  }
-  const mapped = t2;
+  const mapped = t0;
   return mapped;
 }
 function _temp(item_0) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/block-scoping-switch-variable-scoping.expect.md

@@ -50,8 +50,7 @@ function Component(props) {
       console.log(handlers.value);
       break bb0;
     }
-    default: {
-    }
+    default:
   }
 
   t0 = handlers;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-aliased-capture-aliased-mutate.expect.md

@@ -1,107 +0,0 @@
-
-## Input
-
-```javascript
-// @flow @enableTransitivelyFreezeFunctionExpressions:false
-import {arrayPush, setPropertyByKey, Stringify} from 'shared-runtime';
-
-/**
- * 1. `InferMutableRanges` derives the mutable range of identifiers and their
- *     aliases from `LoadLocal`, `PropertyLoad`, etc
- *   - After this pass, y's mutable range only extends to `arrayPush(x, y)`
- *   - We avoid assigning mutable ranges to loads after y's mutable range, as
- *     these are working with an immutable value. As a result, `LoadLocal y` and
- *     `PropertyLoad y` do not get mutable ranges
- * 2. `InferReactiveScopeVariables` extends mutable ranges and creates scopes,
- *    as according to the 'co-mutation' of different values
- *   - Here, we infer that
- *     - `arrayPush(y, x)` might alias `x` and `y` to each other
- *     - `setPropertyKey(x, ...)` may mutate both `x` and `y`
- *   - This pass correctly extends the mutable range of `y`
- *   - Since we didn't run `InferMutableRange` logic again, the LoadLocal /
- *     PropertyLoads still don't have a mutable range
- *
- * Note that the this bug is an edge case. Compiler output is only invalid for:
- *  - function expressions with
- *    `enableTransitivelyFreezeFunctionExpressions:false`
- *  - functions that throw and get retried without clearing the memocache
- *
- * Found differences in evaluator results
- * Non-forget (expected):
- *   (kind: ok)
- *   <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
- *   <div>{"cb":{"kind":"Function","result":11},"shouldInvokeFns":true}</div>
- * Forget:
- *   (kind: ok)
- *   <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
- *   <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
- */
-function useFoo({a, b}: {a: number, b: number}) {
-  const x = [];
-  const y = {value: a};
-
-  arrayPush(x, y); // x and y co-mutate
-  const y_alias = y;
-  const cb = () => y_alias.value;
-  setPropertyByKey(x[0], 'value', b); // might overwrite y.value
-  return <Stringify cb={cb} shouldInvokeFns={true} />;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: useFoo,
-  params: [{a: 2, b: 10}],
-  sequentialRenders: [
-    {a: 2, b: 10},
-    {a: 2, b: 11},
-  ],
-};
-
-```
-
-## Code
-
-```javascript
-import { c as _c } from "react/compiler-runtime";
-import { arrayPush, setPropertyByKey, Stringify } from "shared-runtime";
-
-function useFoo(t0) {
-  const $ = _c(5);
-  const { a, b } = t0;
-  let t1;
-  if ($[0] !== a || $[1] !== b) {
-    const x = [];
-    const y = { value: a };
-
-    arrayPush(x, y);
-    const y_alias = y;
-    let t2;
-    if ($[3] !== y_alias.value) {
-      t2 = () => y_alias.value;
-      $[3] = y_alias.value;
-      $[4] = t2;
-    } else {
-      t2 = $[4];
-    }
-    const cb = t2;
-    setPropertyByKey(x[0], "value", b);
-    t1 = <Stringify cb={cb} shouldInvokeFns={true} />;
-    $[0] = a;
-    $[1] = b;
-    $[2] = t1;
-  } else {
-    t1 = $[2];
-  }
-  return t1;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: useFoo,
-  params: [{ a: 2, b: 10 }],
-  sequentialRenders: [
-    { a: 2, b: 10 },
-    { a: 2, b: 11 },
-  ],
-};
-
-```
-      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-aliased-capture-aliased-mutate.js

@@ -1,53 +0,0 @@
-// @flow @enableTransitivelyFreezeFunctionExpressions:false
-import {arrayPush, setPropertyByKey, Stringify} from 'shared-runtime';
-
-/**
- * 1. `InferMutableRanges` derives the mutable range of identifiers and their
- *     aliases from `LoadLocal`, `PropertyLoad`, etc
- *   - After this pass, y's mutable range only extends to `arrayPush(x, y)`
- *   - We avoid assigning mutable ranges to loads after y's mutable range, as
- *     these are working with an immutable value. As a result, `LoadLocal y` and
- *     `PropertyLoad y` do not get mutable ranges
- * 2. `InferReactiveScopeVariables` extends mutable ranges and creates scopes,
- *    as according to the 'co-mutation' of different values
- *   - Here, we infer that
- *     - `arrayPush(y, x)` might alias `x` and `y` to each other
- *     - `setPropertyKey(x, ...)` may mutate both `x` and `y`
- *   - This pass correctly extends the mutable range of `y`
- *   - Since we didn't run `InferMutableRange` logic again, the LoadLocal /
- *     PropertyLoads still don't have a mutable range
- *
- * Note that the this bug is an edge case. Compiler output is only invalid for:
- *  - function expressions with
- *    `enableTransitivelyFreezeFunctionExpressions:false`
- *  - functions that throw and get retried without clearing the memocache
- *
- * Found differences in evaluator results
- * Non-forget (expected):
- *   (kind: ok)
- *   <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
- *   <div>{"cb":{"kind":"Function","result":11},"shouldInvokeFns":true}</div>
- * Forget:
- *   (kind: ok)
- *   <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
- *   <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
- */
-function useFoo({a, b}: {a: number, b: number}) {
-  const x = [];
-  const y = {value: a};
-
-  arrayPush(x, y); // x and y co-mutate
-  const y_alias = y;
-  const cb = () => y_alias.value;
-  setPropertyByKey(x[0], 'value', b); // might overwrite y.value
-  return <Stringify cb={cb} shouldInvokeFns={true} />;
-}
-
-export const FIXTURE_ENTRYPOINT = {
-  fn: useFoo,
-  params: [{a: 2, b: 10}],
-  sequentialRenders: [
-    {a: 2, b: 10},
-    {a: 2, b: 11},
-  ],
-};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-separate-memoization-due-to-callback-capturing.expect.md

@@ -0,0 +1,171 @@
+
+## Input
+
+```javascript
+import {ValidateMemoization} from 'shared-runtime';
+
+const Codes = {
+  en: {name: 'English'},
+  ja: {name: 'Japanese'},
+  ko: {name: 'Korean'},
+  zh: {name: 'Chinese'},
+};
+
+function Component(a) {
+  let keys;
+  if (a) {
+    keys = Object.keys(Codes);
+  } else {
+    return null;
+  }
+  const options = keys.map(code => {
+    const country = Codes[code];
+    return {
+      name: country.name,
+      code,
+    };
+  });
+  return (
+    <>
+      <ValidateMemoization inputs={[]} output={keys} onlyCheckCompiled={true} />
+      <ValidateMemoization
+        inputs={[]}
+        output={options}
+        onlyCheckCompiled={true}
+      />
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: false}],
+  sequentialRenders: [
+    {a: false},
+    {a: true},
+    {a: true},
+    {a: false},
+    {a: true},
+    {a: false},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { ValidateMemoization } from "shared-runtime";
+
+const Codes = {
+  en: { name: "English" },
+  ja: { name: "Japanese" },
+  ko: { name: "Korean" },
+  zh: { name: "Chinese" },
+};
+
+function Component(a) {
+  const $ = _c(13);
+  let keys;
+  let t0;
+  let t1;
+  if ($[0] !== a) {
+    t1 = Symbol.for("react.early_return_sentinel");
+    bb0: {
+      if (a) {
+        keys = Object.keys(Codes);
+      } else {
+        t1 = null;
+        break bb0;
+      }
+
+      t0 = keys.map(_temp);
+    }
+    $[0] = a;
+    $[1] = t0;
+    $[2] = t1;
+    $[3] = keys;
+  } else {
+    t0 = $[1];
+    t1 = $[2];
+    keys = $[3];
+  }
+  if (t1 !== Symbol.for("react.early_return_sentinel")) {
+    return t1;
+  }
+  const options = t0;
+  let t2;
+  if ($[4] === Symbol.for("react.memo_cache_sentinel")) {
+    t2 = [];
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  let t3;
+  if ($[5] !== keys) {
+    t3 = (
+      <ValidateMemoization inputs={t2} output={keys} onlyCheckCompiled={true} />
+    );
+    $[5] = keys;
+    $[6] = t3;
+  } else {
+    t3 = $[6];
+  }
+  let t4;
+  if ($[7] === Symbol.for("react.memo_cache_sentinel")) {
+    t4 = [];
+    $[7] = t4;
+  } else {
+    t4 = $[7];
+  }
+  let t5;
+  if ($[8] !== options) {
+    t5 = (
+      <ValidateMemoization
+        inputs={t4}
+        output={options}
+        onlyCheckCompiled={true}
+      />
+    );
+    $[8] = options;
+    $[9] = t5;
+  } else {
+    t5 = $[9];
+  }
+  let t6;
+  if ($[10] !== t3 || $[11] !== t5) {
+    t6 = (
+      <>
+        {t3}
+        {t5}
+      </>
+    );
+    $[10] = t3;
+    $[11] = t5;
+    $[12] = t6;
+  } else {
+    t6 = $[12];
+  }
+  return t6;
+}
+function _temp(code) {
+  const country = Codes[code];
+  return { name: country.name, code };
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ a: false }],
+  sequentialRenders: [
+    { a: false },
+    { a: true },
+    { a: true },
+    { a: false },
+    { a: true },
+    { a: false },
+  ],
+};
+
+```
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-separate-memoization-due-to-callback-capturing.js

@@ -0,0 +1,47 @@
+import {ValidateMemoization} from 'shared-runtime';
+
+const Codes = {
+  en: {name: 'English'},
+  ja: {name: 'Japanese'},
+  ko: {name: 'Korean'},
+  zh: {name: 'Chinese'},
+};
+
+function Component(a) {
+  let keys;
+  if (a) {
+    keys = Object.keys(Codes);
+  } else {
+    return null;
+  }
+  const options = keys.map(code => {
+    const country = Codes[code];
+    return {
+      name: country.name,
+      code,
+    };
+  });
+  return (
+    <>
+      <ValidateMemoization inputs={[]} output={keys} onlyCheckCompiled={true} />
+      <ValidateMemoization
+        inputs={[]}
+        output={options}
+        onlyCheckCompiled={true}
+      />
+    </>
+  );
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: false}],
+  sequentialRenders: [
+    {a: false},
+    {a: true},
+    {a: true},
+    {a: false},
+    {a: true},
+    {a: false},
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/dominator.expect.md

@@ -67,8 +67,7 @@ function Component(props) {
     case "b": {
       break bb1;
     }
-    case "c": {
-    }
+    case "c":
     default: {
       x = 6;
     }

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-repro-named-function-with-shadowed-local-same-name.expect.md

@@ -22,7 +22,7 @@ function Component(props) {
    7 |     return hasErrors;
    8 |   }
 >  9 |   return hasErrors();
-     |          ^^^^^^^^^ Invariant: [hoisting] Expected value for identifier to be initialized. hasErrors_0$14 (9:9)
+     |          ^^^^^^^^^ Invariant: [hoisting] Expected value for identifier to be initialized. hasErrors_0$15 (9:9)
   10 | }
   11 |
 ```

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/array-filter.expect.md

@@ -0,0 +1,93 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component({value}) {
+  const arr = [{value: 'foo'}, {value: 'bar'}, {value}];
+  useIdentity(null);
+  const derived = arr.filter(Boolean);
+  return (
+    <Stringify>
+      {derived.at(0)}
+      {derived.at(-1)}
+    </Stringify>
+  );
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function Component(t0) {
+  const $ = _c(13);
+  const { value } = t0;
+  let t1;
+  let t2;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    t1 = { value: "foo" };
+    t2 = { value: "bar" };
+    $[0] = t1;
+    $[1] = t2;
+  } else {
+    t1 = $[0];
+    t2 = $[1];
+  }
+  let t3;
+  if ($[2] !== value) {
+    t3 = [t1, t2, { value }];
+    $[2] = value;
+    $[3] = t3;
+  } else {
+    t3 = $[3];
+  }
+  const arr = t3;
+  useIdentity(null);
+  let t4;
+  if ($[4] !== arr) {
+    t4 = arr.filter(Boolean);
+    $[4] = arr;
+    $[5] = t4;
+  } else {
+    t4 = $[5];
+  }
+  const derived = t4;
+  let t5;
+  if ($[6] !== derived) {
+    t5 = derived.at(0);
+    $[6] = derived;
+    $[7] = t5;
+  } else {
+    t5 = $[7];
+  }
+  let t6;
+  if ($[8] !== derived) {
+    t6 = derived.at(-1);
+    $[8] = derived;
+    $[9] = t6;
+  } else {
+    t6 = $[9];
+  }
+  let t7;
+  if ($[10] !== t5 || $[11] !== t6) {
+    t7 = (
+      <Stringify>
+        {t5}
+        {t6}
+      </Stringify>
+    );
+    $[10] = t5;
+    $[11] = t6;
+    $[12] = t7;
+  } else {
+    t7 = $[12];
+  }
+  return t7;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/array-filter.js

@@ -0,0 +1,12 @@
+// @enableNewMutationAliasingModel
+function Component({value}) {
+  const arr = [{value: 'foo'}, {value: 'bar'}, {value}];
+  useIdentity(null);
+  const derived = arr.filter(Boolean);
+  return (
+    <Stringify>
+      {derived.at(0)}
+      {derived.at(-1)}
+    </Stringify>
+  );
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/array-map-captures-receiver-noAlias.expect.md

@@ -0,0 +1,71 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component(props) {
+  // This item is part of the receiver, should be memoized
+  const item = {a: props.a};
+  const items = [item];
+  const mapped = items.map(item => item);
+  // mapped[0].a = null;
+  return mapped;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: {id: 42}}],
+  isComponent: false,
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function Component(props) {
+  const $ = _c(6);
+  let t0;
+  if ($[0] !== props.a) {
+    t0 = { a: props.a };
+    $[0] = props.a;
+    $[1] = t0;
+  } else {
+    t0 = $[1];
+  }
+  const item = t0;
+  let t1;
+  if ($[2] !== item) {
+    t1 = [item];
+    $[2] = item;
+    $[3] = t1;
+  } else {
+    t1 = $[3];
+  }
+  const items = t1;
+  let t2;
+  if ($[4] !== items) {
+    t2 = items.map(_temp);
+    $[4] = items;
+    $[5] = t2;
+  } else {
+    t2 = $[5];
+  }
+  const mapped = t2;
+  return mapped;
+}
+function _temp(item_0) {
+  return item_0;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ a: { id: 42 } }],
+  isComponent: false,
+};
+
+```
+      
+### Eval output
+(kind: ok) [{"a":{"id":42}}]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/array-map-captures-receiver-noAlias.js

@@ -0,0 +1,15 @@
+// @enableNewMutationAliasingModel
+function Component(props) {
+  // This item is part of the receiver, should be memoized
+  const item = {a: props.a};
+  const items = [item];
+  const mapped = items.map(item => item);
+  // mapped[0].a = null;
+  return mapped;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: {id: 42}}],
+  isComponent: false,
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/array-push.expect.md

@@ -0,0 +1,57 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component({a, b, c}) {
+  const x = [];
+  x.push(a);
+  const merged = {b}; // could be mutated by mutate(x) below
+  x.push(merged);
+  mutate(x);
+  const independent = {c}; // can't be later mutated
+  x.push(independent);
+  return <Foo value={x} />;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function Component(t0) {
+  const $ = _c(6);
+  const { a, b, c } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b || $[2] !== c) {
+    const x = [];
+    x.push(a);
+    const merged = { b };
+    x.push(merged);
+    mutate(x);
+    let t2;
+    if ($[4] !== c) {
+      t2 = { c };
+      $[4] = c;
+      $[5] = t2;
+    } else {
+      t2 = $[5];
+    }
+    const independent = t2;
+    x.push(independent);
+    t1 = <Foo value={x} />;
+    $[0] = a;
+    $[1] = b;
+    $[2] = c;
+    $[3] = t1;
+  } else {
+    t1 = $[3];
+  }
+  return t1;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/array-push.js

@@ -0,0 +1,11 @@
+// @enableNewMutationAliasingModel
+function Component({a, b, c}) {
+  const x = [];
+  x.push(a);
+  const merged = {b}; // could be mutated by mutate(x) below
+  x.push(merged);
+  mutate(x);
+  const independent = {c}; // can't be later mutated
+  x.push(independent);
+  return <Foo value={x} />;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/basic-mutation-via-function-expression.expect.md

@@ -0,0 +1,49 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = {a};
+  const y = [b];
+  const f = () => {
+    y.x = x;
+    mutate(y);
+  };
+  f();
+  return <div>{x}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function Component(t0) {
+  const $ = _c(3);
+  const { a, b } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b) {
+    const x = { a };
+    const y = [b];
+    const f = () => {
+      y.x = x;
+      mutate(y);
+    };
+
+    f();
+    t1 = <div>{x}</div>;
+    $[0] = a;
+    $[1] = b;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  return t1;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/basic-mutation-via-function-expression.js

@@ -0,0 +1,11 @@
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = {a};
+  const y = [b];
+  const f = () => {
+    y.x = x;
+    mutate(y);
+  };
+  f();
+  return <div>{x}</div>;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/basic-mutation.expect.md

@@ -0,0 +1,42 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = {a};
+  const y = [b];
+  y.x = x;
+  mutate(y);
+  return <div>{x}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function Component(t0) {
+  const $ = _c(3);
+  const { a, b } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b) {
+    const x = { a };
+    const y = [b];
+    y.x = x;
+    mutate(y);
+    t1 = <div>{x}</div>;
+    $[0] = a;
+    $[1] = b;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  return t1;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/basic-mutation.js

@@ -0,0 +1,8 @@
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = {a};
+  const y = [b];
+  y.x = x;
+  mutate(y);
+  return <div>{x}</div>;
+}

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

@@ -0,0 +1,87 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+import {identity, mutate} from 'shared-runtime';
+
+/**
+ * Bug: copy of error.todo-object-expression-computed-key-modified-during-after-construction-sequence-expr
+ * with the mutation hoisted to a named variable instead of being directly
+ * inlined into the Object key.
+ *
+ * Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok) [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   Forget:
+ *   (kind: ok) [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe","wat2":"joe"}]
+ */
+function Component(props) {
+  const key = {};
+  const tmp = (mutate(key), key);
+  const context = {
+    // Here, `tmp` is frozen (as it's inferred to be a primitive/string)
+    [tmp]: identity([props.value]),
+  };
+  mutate(key);
+  return [context, key];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 42}],
+  sequentialRenders: [{value: 42}, {value: 42}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+import { identity, mutate } from "shared-runtime";
+
+/**
+ * Bug: copy of error.todo-object-expression-computed-key-modified-during-after-construction-sequence-expr
+ * with the mutation hoisted to a named variable instead of being directly
+ * inlined into the Object key.
+ *
+ * Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok) [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   Forget:
+ *   (kind: ok) [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe","wat2":"joe"}]
+ */
+function Component(props) {
+  const $ = _c(2);
+  let t0;
+  if ($[0] !== props.value) {
+    const key = {};
+    const tmp = (mutate(key), key);
+    const context = { [tmp]: identity([props.value]) };
+
+    mutate(key);
+    t0 = [context, key];
+    $[0] = props.value;
+    $[1] = t0;
+  } else {
+    t0 = $[1];
+  }
+  return t0;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ value: 42 }],
+  sequentialRenders: [{ value: 42 }, { value: 42 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+[{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]

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

@@ -0,0 +1,32 @@
+// @enableNewMutationAliasingModel
+import {identity, mutate} from 'shared-runtime';
+
+/**
+ * Bug: copy of error.todo-object-expression-computed-key-modified-during-after-construction-sequence-expr
+ * with the mutation hoisted to a named variable instead of being directly
+ * inlined into the Object key.
+ *
+ * Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok) [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   Forget:
+ *   (kind: ok) [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe"}]
+ *   [{"[object Object]":[42]},{"wat0":"joe","wat1":"joe","wat2":"joe"}]
+ */
+function Component(props) {
+  const key = {};
+  const tmp = (mutate(key), key);
+  const context = {
+    // Here, `tmp` is frozen (as it's inferred to be a primitive/string)
+    [tmp]: identity([props.value]),
+  };
+  mutate(key);
+  return [context, key];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 42}],
+  sequentialRenders: [{value: 42}, {value: 42}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/capture-backedge-phi-with-later-mutation.expect.md

@@ -0,0 +1,105 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+import {arrayPush, Stringify} from 'shared-runtime';
+
+function Component({prop1, prop2}) {
+  'use memo';
+
+  // we'll ultimately extract the item from this array as z, and mutate later
+  let x = [{value: prop1}];
+  let z;
+  while (x.length < 2) {
+    // there's a phi here for x (value before the loop and the reassignment later)
+
+    // this mutation occurs before the reassigned value
+    arrayPush(x, {value: prop2});
+
+    // this condition will never be true, so x doesn't get reassigned
+    if (x[0].value === null) {
+      x = [{value: prop2}];
+      const y = x;
+      z = y[0];
+    }
+  }
+  // the code is set up so that z will always be the value from the original x
+  z.other = true;
+  return <Stringify z={z} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{prop1: 0, prop2: 0}],
+  sequentialRenders: [
+    {prop1: 0, prop2: 0},
+    {prop1: 1, prop2: 0},
+    {prop1: 1, prop2: 1},
+    {prop1: 0, prop2: 1},
+    {prop1: 0, prop2: 0},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+import { arrayPush, Stringify } from "shared-runtime";
+
+function Component(t0) {
+  "use memo";
+  const $ = _c(5);
+  const { prop1, prop2 } = t0;
+  let z;
+  if ($[0] !== prop1 || $[1] !== prop2) {
+    let x = [{ value: prop1 }];
+    while (x.length < 2) {
+      arrayPush(x, { value: prop2 });
+      if (x[0].value === null) {
+        x = [{ value: prop2 }];
+        const y = x;
+        z = y[0];
+      }
+    }
+
+    z.other = true;
+    $[0] = prop1;
+    $[1] = prop2;
+    $[2] = z;
+  } else {
+    z = $[2];
+  }
+  let t1;
+  if ($[3] !== z) {
+    t1 = <Stringify z={z} />;
+    $[3] = z;
+    $[4] = t1;
+  } else {
+    t1 = $[4];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ prop1: 0, prop2: 0 }],
+  sequentialRenders: [
+    { prop1: 0, prop2: 0 },
+    { prop1: 1, prop2: 0 },
+    { prop1: 1, prop2: 1 },
+    { prop1: 0, prop2: 1 },
+    { prop1: 0, prop2: 0 },
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) [[ (exception in render) TypeError: Cannot set properties of undefined (setting 'other') ]]
+[[ (exception in render) TypeError: Cannot set properties of undefined (setting 'other') ]]
+[[ (exception in render) TypeError: Cannot set properties of undefined (setting 'other') ]]
+[[ (exception in render) TypeError: Cannot set properties of undefined (setting 'other') ]]
+[[ (exception in render) TypeError: Cannot set properties of undefined (setting 'other') ]]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/capture-backedge-phi-with-later-mutation.js

@@ -0,0 +1,35 @@
+// @enableNewMutationAliasingModel
+import {arrayPush, Stringify} from 'shared-runtime';
+
+function Component({prop1, prop2}) {
+  'use memo';
+
+  let x = [{value: prop1}];
+  let z;
+  while (x.length < 2) {
+    // there's a phi here for x (value before the loop and the reassignment later)
+
+    // this mutation occurs before the reassigned value
+    arrayPush(x, {value: prop2});
+
+    if (x[0].value === prop1) {
+      x = [{value: prop2}];
+      const y = x;
+      z = y[0];
+    }
+  }
+  z.other = true;
+  return <Stringify z={z} />;
+}
+
+// export const FIXTURE_ENTRYPOINT = {
+//   fn: Component,
+//   params: [{prop1: 0, prop2: 0}],
+//   sequentialRenders: [
+//     {prop1: 0, prop2: 0},
+//     {prop1: 1, prop2: 0},
+//     {prop1: 1, prop2: 1},
+//     {prop1: 0, prop2: 1},
+//     {prop1: 0, prop2: 0},
+//   ],
+// };

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

@@ -0,0 +1,43 @@
+
+## Input
+
+```javascript
+// @validatePreserveExistingMemoizationGuarantees @enableNewMutationAliasingModel
+import {useCallback} from 'react';
+import {makeArray} from 'shared-runtime';
+
+// This case is already unsound in source, so we can safely bailout
+function Foo(props) {
+  let x = [];
+  x.push(props);
+
+  // makeArray() is captured, but depsList contains [props]
+  const cb = useCallback(() => [x], [x]);
+
+  x = makeArray();
+
+  return cb;
+}
+export const FIXTURE_ENTRYPOINT = {
+  fn: Foo,
+  params: [{}],
+};
+
+```
+
+
+## Error
+
+```
+   9 |
+  10 |   // makeArray() is captured, but depsList contains [props]
+> 11 |   const cb = useCallback(() => [x], [x]);
+     |                                      ^ CannotPreserveMemoization: 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 (11:11)
+
+CannotPreserveMemoization: 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. (11:11)
+  12 |
+  13 |   x = makeArray();
+  14 |
+```
+          
+      

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

@@ -0,0 +1,20 @@
+// @validatePreserveExistingMemoizationGuarantees @enableNewMutationAliasingModel
+import {useCallback} from 'react';
+import {makeArray} from 'shared-runtime';
+
+// This case is already unsound in source, so we can safely bailout
+function Foo(props) {
+  let x = [];
+  x.push(props);
+
+  // makeArray() is captured, but depsList contains [props]
+  const cb = useCallback(() => [x], [x]);
+
+  x = makeArray();
+
+  return cb;
+}
+export const FIXTURE_ENTRYPOINT = {
+  fn: Foo,
+  params: [{}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/error.mutate-frozen-value.expect.md

@@ -0,0 +1,28 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = {a};
+  useFreeze(x);
+  x.y = true;
+  return <div>error</div>;
+}
+
+```
+
+
+## Error
+
+```
+  3 |   const x = {a};
+  4 |   useFreeze(x);
+> 5 |   x.y = true;
+    |   ^ InvalidReact: This mutates a variable that React considers immutable (5:5)
+  6 |   return <div>error</div>;
+  7 | }
+  8 |
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/error.mutate-frozen-value.js

@@ -0,0 +1,7 @@
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = {a};
+  useFreeze(x);
+  x.y = true;
+  return <div>error</div>;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/iife-return-modified-later-phi.expect.md

@@ -0,0 +1,58 @@
+
+## Input
+
+```javascript
+function Component(props) {
+  const items = (() => {
+    if (props.cond) {
+      return [];
+    } else {
+      return null;
+    }
+  })();
+  items?.push(props.a);
+  return items;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: {}}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+function Component(props) {
+  const $ = _c(3);
+  let items;
+  if ($[0] !== props.a || $[1] !== props.cond) {
+    let t0;
+    if (props.cond) {
+      t0 = [];
+    } else {
+      t0 = null;
+    }
+    items = t0;
+
+    items?.push(props.a);
+    $[0] = props.a;
+    $[1] = props.cond;
+    $[2] = items;
+  } else {
+    items = $[2];
+  }
+  return items;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ a: {} }],
+};
+
+```
+      
+### Eval output
+(kind: ok) null

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/iife-return-modified-later-phi.js

@@ -0,0 +1,16 @@
+function Component(props) {
+  const items = (() => {
+    if (props.cond) {
+      return [];
+    } else {
+      return null;
+    }
+  })();
+  items?.push(props.a);
+  return items;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: {}}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/mutate-through-boxing-unboxing-function-call-indirections-2.expect.md

@@ -0,0 +1,67 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+import {Stringify} from 'shared-runtime';
+
+function Component({a, b}) {
+  const x = {a, b};
+  const f = () => {
+    const y = [x];
+    return y[0];
+  };
+  const x0 = f();
+  const z = [x0];
+  const x1 = z[0];
+  x1.key = 'value';
+  return <Stringify x={x} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: 0, b: 1}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+import { Stringify } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(3);
+  const { a, b } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b) {
+    const x = { a, b };
+    const f = () => {
+      const y = [x];
+      return y[0];
+    };
+
+    const x0 = f();
+    const z = [x0];
+    const x1 = z[0];
+    x1.key = "value";
+    t1 = <Stringify x={x} />;
+    $[0] = a;
+    $[1] = b;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ a: 0, b: 1 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"x":{"a":0,"b":1,"key":"value"}}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/mutate-through-boxing-unboxing-function-call-indirections-2.js

@@ -0,0 +1,20 @@
+// @enableNewMutationAliasingModel
+import {Stringify} from 'shared-runtime';
+
+function Component({a, b}) {
+  const x = {a, b};
+  const f = () => {
+    const y = [x];
+    return y[0];
+  };
+  const x0 = f();
+  const z = [x0];
+  const x1 = z[0];
+  x1.key = 'value';
+  return <Stringify x={x} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: 0, b: 1}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/mutate-through-boxing-unboxing-function-call-indirections.expect.md

@@ -0,0 +1,67 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+import {Stringify} from 'shared-runtime';
+
+function Component({a, b}) {
+  const x = {a, b};
+  const y = [x];
+  const f = () => {
+    const x0 = y[0];
+    return [x0];
+  };
+  const z = f();
+  const x1 = z[0];
+  x1.key = 'value';
+  return <Stringify x={x} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: 0, b: 1}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+import { Stringify } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(3);
+  const { a, b } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b) {
+    const x = { a, b };
+    const y = [x];
+    const f = () => {
+      const x0 = y[0];
+      return [x0];
+    };
+
+    const z = f();
+    const x1 = z[0];
+    x1.key = "value";
+    t1 = <Stringify x={x} />;
+    $[0] = a;
+    $[1] = b;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ a: 0, b: 1 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"x":{"a":0,"b":1,"key":"value"}}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/mutate-through-boxing-unboxing-function-call-indirections.js

@@ -0,0 +1,20 @@
+// @enableNewMutationAliasingModel
+import {Stringify} from 'shared-runtime';
+
+function Component({a, b}) {
+  const x = {a, b};
+  const y = [x];
+  const f = () => {
+    const x0 = y[0];
+    return [x0];
+  };
+  const z = f();
+  const x1 = z[0];
+  x1.key = 'value';
+  return <Stringify x={x} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: 0, b: 1}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/mutate-through-boxing-unboxing-indirections.expect.md

@@ -0,0 +1,60 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+import {Stringify} from 'shared-runtime';
+
+function Component({a, b}) {
+  const x = {a, b};
+  const y = [x];
+  const x0 = y[0];
+  const z = [x0];
+  const x1 = z[0];
+  x1.key = 'value';
+  return <Stringify x={x} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: 0, b: 1}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+import { Stringify } from "shared-runtime";
+
+function Component(t0) {
+  const $ = _c(3);
+  const { a, b } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b) {
+    const x = { a, b };
+    const y = [x];
+    const x0 = y[0];
+    const z = [x0];
+    const x1 = z[0];
+    x1.key = "value";
+    t1 = <Stringify x={x} />;
+    $[0] = a;
+    $[1] = b;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ a: 0, b: 1 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"x":{"a":0,"b":1,"key":"value"}}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/mutate-through-boxing-unboxing-indirections.js

@@ -0,0 +1,17 @@
+// @enableNewMutationAliasingModel
+import {Stringify} from 'shared-runtime';
+
+function Component({a, b}) {
+  const x = {a, b};
+  const y = [x];
+  const x0 = y[0];
+  const z = [x0];
+  const x1 = z[0];
+  x1.key = 'value';
+  return <Stringify x={x} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: 0, b: 1}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/mutate-through-propertyload.expect.md

@@ -0,0 +1,39 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = {};
+  const y = {x};
+  const z = y.x;
+  z.true = false;
+  return <div>{z}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function Component(t0) {
+  const $ = _c(1);
+  let t1;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    const x = {};
+    const y = { x };
+    const z = y.x;
+    z.true = false;
+    t1 = <div>{z}</div>;
+    $[0] = t1;
+  } else {
+    t1 = $[0];
+  }
+  return t1;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/mutate-through-propertyload.js

@@ -0,0 +1,8 @@
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = {};
+  const y = {x};
+  const z = y.x;
+  z.true = false;
+  return <div>{z}</div>;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/nullable-objects-assume-invoked-direct-call.expect.md

@@ -0,0 +1,75 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+import {useState} from 'react';
+import {useIdentity} from 'shared-runtime';
+
+function useMakeCallback({obj}: {obj: {value: number}}) {
+  const [state, setState] = useState(0);
+  const cb = () => {
+    if (obj.value !== state) setState(obj.value);
+  };
+  useIdentity();
+  cb();
+  return [cb];
+}
+export const FIXTURE_ENTRYPOINT = {
+  fn: useMakeCallback,
+  params: [{obj: {value: 1}}],
+  sequentialRenders: [{obj: {value: 1}}, {obj: {value: 2}}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+import { useState } from "react";
+import { useIdentity } from "shared-runtime";
+
+function useMakeCallback(t0) {
+  const $ = _c(5);
+  const { obj } = t0;
+  const [state, setState] = useState(0);
+  let t1;
+  if ($[0] !== obj.value || $[1] !== state) {
+    t1 = () => {
+      if (obj.value !== state) {
+        setState(obj.value);
+      }
+    };
+    $[0] = obj.value;
+    $[1] = state;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  const cb = t1;
+
+  useIdentity();
+  cb();
+  let t2;
+  if ($[3] !== cb) {
+    t2 = [cb];
+    $[3] = cb;
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  return t2;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useMakeCallback,
+  params: [{ obj: { value: 1 } }],
+  sequentialRenders: [{ obj: { value: 1 } }, { obj: { value: 2 } }],
+};
+
+```
+      
+### Eval output
+(kind: ok) ["[[ function params=0 ]]"]
+["[[ function params=0 ]]"]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/nullable-objects-assume-invoked-direct-call.js

@@ -0,0 +1,18 @@
+// @enableNewMutationAliasingModel
+import {useState} from 'react';
+import {useIdentity} from 'shared-runtime';
+
+function useMakeCallback({obj}: {obj: {value: number}}) {
+  const [state, setState] = useState(0);
+  const cb = () => {
+    if (obj.value !== state) setState(obj.value);
+  };
+  useIdentity();
+  cb();
+  return [cb];
+}
+export const FIXTURE_ENTRYPOINT = {
+  fn: useMakeCallback,
+  params: [{obj: {value: 1}}],
+  sequentialRenders: [{obj: {value: 1}}, {obj: {value: 2}}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/potential-mutation-in-function-expression.expect.md

@@ -0,0 +1,64 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component({a, b, c}) {
+  const x = [a, b];
+  const f = () => {
+    maybeMutate(x);
+    // different dependency to force this not to merge with x's scope
+    console.log(c);
+  };
+  return <Foo onClick={f} value={x} />;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function Component(t0) {
+  const $ = _c(9);
+  const { a, b, c } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b) {
+    t1 = [a, b];
+    $[0] = a;
+    $[1] = b;
+    $[2] = t1;
+  } else {
+    t1 = $[2];
+  }
+  const x = t1;
+  let t2;
+  if ($[3] !== c || $[4] !== x) {
+    t2 = () => {
+      maybeMutate(x);
+
+      console.log(c);
+    };
+    $[3] = c;
+    $[4] = x;
+    $[5] = t2;
+  } else {
+    t2 = $[5];
+  }
+  const f = t2;
+  let t3;
+  if ($[6] !== f || $[7] !== x) {
+    t3 = <Foo onClick={f} value={x} />;
+    $[6] = f;
+    $[7] = x;
+    $[8] = t3;
+  } else {
+    t3 = $[8];
+  }
+  return t3;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/potential-mutation-in-function-expression.js

@@ -0,0 +1,10 @@
+// @enableNewMutationAliasingModel
+function Component({a, b, c}) {
+  const x = [a, b];
+  const f = () => {
+    maybeMutate(x);
+    // different dependency to force this not to merge with x's scope
+    console.log(c);
+  };
+  return <Foo onClick={f} value={x} />;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/reactive-ref.expect.md

@@ -0,0 +1,54 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function ReactiveRefInEffect(props) {
+  const ref1 = useRef('initial value');
+  const ref2 = useRef('initial value');
+  let ref;
+  if (props.foo) {
+    ref = ref1;
+  } else {
+    ref = ref2;
+  }
+  useEffect(() => print(ref));
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function ReactiveRefInEffect(props) {
+  const $ = _c(4);
+  const ref1 = useRef("initial value");
+  const ref2 = useRef("initial value");
+  let ref;
+  if ($[0] !== props.foo) {
+    if (props.foo) {
+      ref = ref1;
+    } else {
+      ref = ref2;
+    }
+    $[0] = props.foo;
+    $[1] = ref;
+  } else {
+    ref = $[1];
+  }
+  let t0;
+  if ($[2] !== ref) {
+    t0 = () => print(ref);
+    $[2] = ref;
+    $[3] = t0;
+  } else {
+    t0 = $[3];
+  }
+  useEffect(t0);
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/reactive-ref.js

@@ -0,0 +1,12 @@
+// @enableNewMutationAliasingModel
+function ReactiveRefInEffect(props) {
+  const ref1 = useRef('initial value');
+  const ref2 = useRef('initial value');
+  let ref;
+  if (props.foo) {
+    ref = ref1;
+  } else {
+    ref = ref2;
+  }
+  useEffect(() => print(ref));
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/repro-capturing-func-maybealias-captured-mutate.expect.md

@@ -0,0 +1,125 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+import {makeArray, mutate} from 'shared-runtime';
+
+/**
+ * Bug repro:
+ * Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok)
+ *   {"bar":4,"x":{"foo":3,"wat0":"joe"}}
+ *   {"bar":5,"x":{"foo":3,"wat0":"joe"}}
+ *   Forget:
+ *   (kind: ok)
+ *   {"bar":4,"x":{"foo":3,"wat0":"joe"}}
+ *   {"bar":5,"x":{"foo":3,"wat0":"joe","wat1":"joe"}}
+ *
+ * Fork of `capturing-func-alias-captured-mutate`, but instead of directly
+ * aliasing `y` via `[y]`, we make an opaque call.
+ *
+ * Note that the bug here is that we don't infer that `a = makeArray(y)`
+ * potentially captures a context variable into a local variable. As a result,
+ * we don't understand that `a[0].x = b` captures `x` into `y` -- instead, we're
+ * currently inferring that this lambda captures `y` (for a potential later
+ * mutation) and simply reads `x`.
+ *
+ * Concretely `InferReferenceEffects.hasContextRefOperand` is incorrectly not
+ * used when we analyze CallExpressions.
+ */
+function Component({foo, bar}: {foo: number; bar: number}) {
+  let x = {foo};
+  let y: {bar: number; x?: {foo: number}} = {bar};
+  const f0 = function () {
+    let a = makeArray(y); // a = [y]
+    let b = x;
+    // this writes y.x = x
+    a[0].x = b;
+  };
+  f0();
+  mutate(y.x);
+  return y;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{foo: 3, bar: 4}],
+  sequentialRenders: [
+    {foo: 3, bar: 4},
+    {foo: 3, bar: 5},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+import { makeArray, mutate } from "shared-runtime";
+
+/**
+ * Bug repro:
+ * Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok)
+ *   {"bar":4,"x":{"foo":3,"wat0":"joe"}}
+ *   {"bar":5,"x":{"foo":3,"wat0":"joe"}}
+ *   Forget:
+ *   (kind: ok)
+ *   {"bar":4,"x":{"foo":3,"wat0":"joe"}}
+ *   {"bar":5,"x":{"foo":3,"wat0":"joe","wat1":"joe"}}
+ *
+ * Fork of `capturing-func-alias-captured-mutate`, but instead of directly
+ * aliasing `y` via `[y]`, we make an opaque call.
+ *
+ * Note that the bug here is that we don't infer that `a = makeArray(y)`
+ * potentially captures a context variable into a local variable. As a result,
+ * we don't understand that `a[0].x = b` captures `x` into `y` -- instead, we're
+ * currently inferring that this lambda captures `y` (for a potential later
+ * mutation) and simply reads `x`.
+ *
+ * Concretely `InferReferenceEffects.hasContextRefOperand` is incorrectly not
+ * used when we analyze CallExpressions.
+ */
+function Component(t0) {
+  const $ = _c(3);
+  const { foo, bar } = t0;
+  let y;
+  if ($[0] !== bar || $[1] !== foo) {
+    const x = { foo };
+    y = { bar };
+    const f0 = function () {
+      const a = makeArray(y);
+      const b = x;
+
+      a[0].x = b;
+    };
+
+    f0();
+    mutate(y.x);
+    $[0] = bar;
+    $[1] = foo;
+    $[2] = y;
+  } else {
+    y = $[2];
+  }
+  return y;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ foo: 3, bar: 4 }],
+  sequentialRenders: [
+    { foo: 3, bar: 4 },
+    { foo: 3, bar: 5 },
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) {"bar":4,"x":{"foo":3,"wat0":"joe"}}
+{"bar":5,"x":{"foo":3,"wat0":"joe"}}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/repro-capturing-func-maybealias-captured-mutate.ts

@@ -0,0 +1,49 @@
+// @enableNewMutationAliasingModel
+import {makeArray, mutate} from 'shared-runtime';
+
+/**
+ * Bug repro:
+ * Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok)
+ *   {"bar":4,"x":{"foo":3,"wat0":"joe"}}
+ *   {"bar":5,"x":{"foo":3,"wat0":"joe"}}
+ *   Forget:
+ *   (kind: ok)
+ *   {"bar":4,"x":{"foo":3,"wat0":"joe"}}
+ *   {"bar":5,"x":{"foo":3,"wat0":"joe","wat1":"joe"}}
+ *
+ * Fork of `capturing-func-alias-captured-mutate`, but instead of directly
+ * aliasing `y` via `[y]`, we make an opaque call.
+ *
+ * Note that the bug here is that we don't infer that `a = makeArray(y)`
+ * potentially captures a context variable into a local variable. As a result,
+ * we don't understand that `a[0].x = b` captures `x` into `y` -- instead, we're
+ * currently inferring that this lambda captures `y` (for a potential later
+ * mutation) and simply reads `x`.
+ *
+ * Concretely `InferReferenceEffects.hasContextRefOperand` is incorrectly not
+ * used when we analyze CallExpressions.
+ */
+function Component({foo, bar}: {foo: number; bar: number}) {
+  let x = {foo};
+  let y: {bar: number; x?: {foo: number}} = {bar};
+  const f0 = function () {
+    let a = makeArray(y); // a = [y]
+    let b = x;
+    // this writes y.x = x
+    a[0].x = b;
+  };
+  f0();
+  mutate(y.x);
+  return y;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{foo: 3, bar: 4}],
+  sequentialRenders: [
+    {foo: 3, bar: 4},
+    {foo: 3, bar: 5},
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/set-add-mutate.expect.md

@@ -0,0 +1,54 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function useHook({el1, el2}) {
+  const s = new Set();
+  const arr = makeArray(el1);
+  s.add(arr);
+  // Mutate after store
+  arr.push(el2);
+
+  s.add(makeArray(el2));
+  return s.size;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function useHook(t0) {
+  const $ = _c(5);
+  const { el1, el2 } = t0;
+  let s;
+  if ($[0] !== el1 || $[1] !== el2) {
+    s = new Set();
+    const arr = makeArray(el1);
+    s.add(arr);
+
+    arr.push(el2);
+    let t1;
+    if ($[3] !== el2) {
+      t1 = makeArray(el2);
+      $[3] = el2;
+      $[4] = t1;
+    } else {
+      t1 = $[4];
+    }
+    s.add(t1);
+    $[0] = el1;
+    $[1] = el2;
+    $[2] = s;
+  } else {
+    s = $[2];
+  }
+  return s.size;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/set-add-mutate.js

@@ -0,0 +1,11 @@
+// @enableNewMutationAliasingModel
+function useHook({el1, el2}) {
+  const s = new Set();
+  const arr = makeArray(el1);
+  s.add(arr);
+  // Mutate after store
+  arr.push(el2);
+
+  s.add(makeArray(el2));
+  return s.size;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/ssa-renaming-ternary-destruction.expect.md

@@ -0,0 +1,70 @@
+
+## Input
+
+```javascript
+// @enablePropagateDepsInHIR @enableNewMutationAliasingModel
+function useFoo(props) {
+  let x = [];
+  x.push(props.bar);
+  // todo: the below should memoize separately from the above
+  // my guess is that the phi causes the different `x` identifiers
+  // to get added to an alias group. this is where we need to track
+  // the actual state of the alias groups at the time of the mutation
+  props.cond ? (({x} = {x: {}}), ([x] = [[]]), x.push(props.foo)) : null;
+  return x;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{cond: false, foo: 2, bar: 55}],
+  sequentialRenders: [
+    {cond: false, foo: 2, bar: 55},
+    {cond: false, foo: 3, bar: 55},
+    {cond: true, foo: 3, bar: 55},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enablePropagateDepsInHIR @enableNewMutationAliasingModel
+function useFoo(props) {
+  const $ = _c(5);
+  let x;
+  if ($[0] !== props.bar) {
+    x = [];
+    x.push(props.bar);
+    $[0] = props.bar;
+    $[1] = x;
+  } else {
+    x = $[1];
+  }
+  if ($[2] !== props.cond || $[3] !== props.foo) {
+    props.cond ? (([x] = [[]]), x.push(props.foo)) : null;
+    $[2] = props.cond;
+    $[3] = props.foo;
+    $[4] = x;
+  } else {
+    x = $[4];
+  }
+  return x;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{ cond: false, foo: 2, bar: 55 }],
+  sequentialRenders: [
+    { cond: false, foo: 2, bar: 55 },
+    { cond: false, foo: 3, bar: 55 },
+    { cond: true, foo: 3, bar: 55 },
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) [55]
+[55]
+[3]

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/ssa-renaming-ternary-destruction.js

@@ -0,0 +1,21 @@
+// @enablePropagateDepsInHIR @enableNewMutationAliasingModel
+function useFoo(props) {
+  let x = [];
+  x.push(props.bar);
+  // todo: the below should memoize separately from the above
+  // my guess is that the phi causes the different `x` identifiers
+  // to get added to an alias group. this is where we need to track
+  // the actual state of the alias groups at the time of the mutation
+  props.cond ? (({x} = {x: {}}), ([x] = [[]]), x.push(props.foo)) : null;
+  return x;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{cond: false, foo: 2, bar: 55}],
+  sequentialRenders: [
+    {cond: false, foo: 2, bar: 55},
+    {cond: false, foo: 3, bar: 55},
+    {cond: true, foo: 3, bar: 55},
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/transitive-mutation-before-capturing-value-created-earlier.expect.md

@@ -0,0 +1,50 @@
+
+## Input
+
+```javascript
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = [a];
+  const y = {b};
+  mutate(y);
+  y.x = x;
+  return <div>{y}</div>;
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @enableNewMutationAliasingModel
+function Component(t0) {
+  const $ = _c(5);
+  const { a, b } = t0;
+  let t1;
+  if ($[0] !== a) {
+    t1 = [a];
+    $[0] = a;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  const x = t1;
+  let t2;
+  if ($[2] !== b || $[3] !== x) {
+    const y = { b };
+    mutate(y);
+    y.x = x;
+    t2 = <div>{y}</div>;
+    $[2] = b;
+    $[3] = x;
+    $[4] = t2;
+  } else {
+    t2 = $[4];
+  }
+  return t2;
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/new-mutability/transitive-mutation-before-capturing-value-created-earlier.js

@@ -0,0 +1,8 @@
+// @enableNewMutationAliasingModel
+function Component({a, b}) {
+  const x = [a];
+  const y = {b};
+  mutate(y);
+  y.x = x;
+  return <div>{y}</div>;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/object-access-assignment.expect.md

@@ -0,0 +1,83 @@
+
+## Input
+
+```javascript
+function Component({a, b, c}) {
+  // This is an object version of array-access-assignment.js
+  // Meant to confirm that object expressions and PropertyStore/PropertyLoad with strings
+  // works equivalently to array expressions and property accesses with numeric indices
+  const x = {zero: a};
+  const y = {zero: null, one: b};
+  const z = {zero: {}, one: {}, two: {zero: c}};
+  x.zero = y.one;
+  z.zero.zero = x.zero;
+  return {zero: x, one: z};
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: 1, b: 20, c: 300}],
+  sequentialRenders: [
+    {a: 2, b: 20, c: 300},
+    {a: 3, b: 20, c: 300},
+    {a: 3, b: 21, c: 300},
+    {a: 3, b: 22, c: 300},
+    {a: 3, b: 22, c: 301},
+  ],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+function Component(t0) {
+  const $ = _c(6);
+  const { a, b, c } = t0;
+  let t1;
+  if ($[0] !== a || $[1] !== b || $[2] !== c) {
+    const x = { zero: a };
+    let t2;
+    if ($[4] !== b) {
+      t2 = { zero: null, one: b };
+      $[4] = b;
+      $[5] = t2;
+    } else {
+      t2 = $[5];
+    }
+    const y = t2;
+    const z = { zero: {}, one: {}, two: { zero: c } };
+    x.zero = y.one;
+    z.zero.zero = x.zero;
+    t1 = { zero: x, one: z };
+    $[0] = a;
+    $[1] = b;
+    $[2] = c;
+    $[3] = t1;
+  } else {
+    t1 = $[3];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ a: 1, b: 20, c: 300 }],
+  sequentialRenders: [
+    { a: 2, b: 20, c: 300 },
+    { a: 3, b: 20, c: 300 },
+    { a: 3, b: 21, c: 300 },
+    { a: 3, b: 22, c: 300 },
+    { a: 3, b: 22, c: 301 },
+  ],
+};
+
+```
+      
+### Eval output
+(kind: ok) {"zero":{"zero":20},"one":{"zero":{"zero":20},"one":{},"two":{"zero":300}}}
+{"zero":{"zero":20},"one":{"zero":{"zero":20},"one":{},"two":{"zero":300}}}
+{"zero":{"zero":21},"one":{"zero":{"zero":21},"one":{},"two":{"zero":300}}}
+{"zero":{"zero":22},"one":{"zero":{"zero":22},"one":{},"two":{"zero":300}}}
+{"zero":{"zero":22},"one":{"zero":{"zero":22},"one":{},"two":{"zero":301}}}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/object-access-assignment.js

@@ -0,0 +1,23 @@
+function Component({a, b, c}) {
+  // This is an object version of array-access-assignment.js
+  // Meant to confirm that object expressions and PropertyStore/PropertyLoad with strings
+  // works equivalently to array expressions and property accesses with numeric indices
+  const x = {zero: a};
+  const y = {zero: null, one: b};
+  const z = {zero: {}, one: {}, two: {zero: c}};
+  x.zero = y.one;
+  z.zero.zero = x.zero;
+  return {zero: x, one: z};
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{a: 1, b: 20, c: 300}],
+  sequentialRenders: [
+    {a: 2, b: 20, c: 300},
+    {a: 3, b: 20, c: 300},
+    {a: 3, b: 21, c: 300},
+    {a: 3, b: 22, c: 300},
+    {a: 3, b: 22, c: 301},
+  ],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-local-mutation-incorrectly-flagged-as-context-mutation.expect.md

@@ -0,0 +1,89 @@
+
+## Input
+
+```javascript
+// @validateNoFreezingKnownMutableFunctions
+
+import {useCallback, useEffect, useRef} from 'react';
+import {useHook} from 'shared-runtime';
+
+function Component() {
+  const params = useHook();
+  const update = useCallback(
+    partialParams => {
+      const nextParams = {
+        ...params,
+        ...partialParams,
+      };
+      // Due to how we previously represented ObjectExpressions in InferReferenceEffects,
+      // this was recorded as a mutation of a context value (`params`) which then made
+      // the function appear ineligible for freezing when passing to useEffect below.
+      nextParams.param = 'value';
+      console.log(nextParams);
+    },
+    [params]
+  );
+  const ref = useRef(null);
+  useEffect(() => {
+    if (ref.current === null) {
+      update();
+    }
+  }, [update]);
+
+  return 'ok';
+}
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoFreezingKnownMutableFunctions
+
+import { useCallback, useEffect, useRef } from "react";
+import { useHook } from "shared-runtime";
+
+function Component() {
+  const $ = _c(5);
+  const params = useHook();
+  let t0;
+  if ($[0] !== params) {
+    t0 = (partialParams) => {
+      const nextParams = { ...params, ...partialParams };
+
+      nextParams.param = "value";
+      console.log(nextParams);
+    };
+    $[0] = params;
+    $[1] = t0;
+  } else {
+    t0 = $[1];
+  }
+  const update = t0;
+
+  const ref = useRef(null);
+  let t1;
+  let t2;
+  if ($[2] !== update) {
+    t1 = () => {
+      if (ref.current === null) {
+        update();
+      }
+    };
+
+    t2 = [update];
+    $[2] = update;
+    $[3] = t1;
+    $[4] = t2;
+  } else {
+    t1 = $[3];
+    t2 = $[4];
+  }
+  useEffect(t1, t2);
+  return "ok";
+}
+
+```
+      
+### Eval output
+(kind: exception) Fixture not implemented

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-local-mutation-incorrectly-flagged-as-context-mutation.js

@@ -0,0 +1,30 @@
+// @validateNoFreezingKnownMutableFunctions
+
+import {useCallback, useEffect, useRef} from 'react';
+import {useHook} from 'shared-runtime';
+
+function Component() {
+  const params = useHook();
+  const update = useCallback(
+    partialParams => {
+      const nextParams = {
+        ...params,
+        ...partialParams,
+      };
+      // Due to how we previously represented ObjectExpressions in InferReferenceEffects,
+      // this was recorded as a mutation of a context value (`params`) which then made
+      // the function appear ineligible for freezing when passing to useEffect below.
+      nextParams.param = 'value';
+      console.log(nextParams);
+    },
+    [params]
+  );
+  const ref = useRef(null);
+  useEffect(() => {
+    if (ref.current === null) {
+      update();
+    }
+  }, [update]);
+
+  return 'ok';
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/reverse-postorder.expect.md

@@ -50,10 +50,8 @@ function Component(props) {
       case 1: {
         break bb0;
       }
-      case 2: {
-      }
-      default: {
-      }
+      case 2:
+      default:
     }
   } else {
     if (props.cond2) {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/ssa-switch.expect.md

@@ -41,8 +41,7 @@ function foo() {
     case 2: {
       break bb0;
     }
-    default: {
-    }
+    default:
   }
 }
 

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/switch-with-fallthrough.expect.md

@@ -43,22 +43,17 @@ export const FIXTURE_ENTRYPOINT = {
 ```javascript
 function foo(x) {
   bb0: switch (x) {
-    case 0: {
-    }
-    case 1: {
-    }
+    case 0:
+    case 1:
     case 2: {
       break bb0;
     }
     case 3: {
       break bb0;
     }
-    case 4: {
-    }
-    case 5: {
-    }
-    default: {
-    }
+    case 4:
+    case 5:
+    default:
   }
 }
 

compiler/packages/snap/src/SproutTodoFilter.ts

@@ -453,8 +453,6 @@ const skipFilter = new Set([
   'inner-function/nullable-objects/bug-invalid-array-map-manual',
   'bug-object-expression-computed-key-modified-during-after-construction-hoisted-sequence-expr',
   `bug-capturing-func-maybealias-captured-mutate`,
-  'bug-aliased-capture-aliased-mutate',
-  'bug-aliased-capture-mutate',
   'bug-functiondecl-hoisting',
   'bug-type-inference-control-flow',
   'fbt/bug-fbt-plural-multiple-function-calls',
@@ -485,6 +483,7 @@ const skipFilter = new Set([
   'todo.lower-context-access-array-destructuring',
   'lower-context-selector-simple',
   'lower-context-acess-multiple',
+  'bug-separate-memoization-due-to-callback-capturing',
 ]);
 
 export default skipFilter;

compiler/packages/snap/src/sprout/index.ts

@@ -42,6 +42,7 @@ export function runSprout(
     (globalThis as any).__SNAP_EVALUATOR_MODE = undefined;
   }
   if (forgetResult.kind === 'UnexpectedError') {
+    console.log(forgetCode);
     return makeError('Unexpected error in Forget runner', forgetResult.value);
   }
   if (originalCode.indexOf('@disableNonForgetInSprout') === -1) {