| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | */ |
| 7 | |
| 8 | import { |
| 9 | CompilerDiagnostic, |
| 10 | CompilerError, |
| 11 | ErrorCategory, |
| 12 | } from '../CompilerError'; |
| 13 | import { |
| 14 | DeclarationId, |
| 15 | Effect, |
| 16 | GeneratedSource, |
| 17 | Identifier, |
| 18 | IdentifierId, |
| 19 | InstructionValue, |
| 20 | ManualMemoDependency, |
| 21 | PrunedReactiveScopeBlock, |
| 22 | ReactiveFunction, |
| 23 | ReactiveInstruction, |
| 24 | ReactiveScopeBlock, |
| 25 | ReactiveScopeDependency, |
| 26 | ReactiveValue, |
| 27 | ScopeId, |
| 28 | SourceLocation, |
| 29 | } from '../HIR'; |
| 30 | import {Environment} from '../HIR/Environment'; |
| 31 | import {printIdentifier, printManualMemoDependency} from '../HIR/PrintHIR'; |
| 32 | import { |
| 33 | eachInstructionValueLValue, |
| 34 | eachInstructionValueOperand, |
| 35 | } from '../HIR/visitors'; |
| 36 | import {collectMaybeMemoDependencies} from '../Inference/DropManualMemoization'; |
| 37 | import { |
| 38 | ReactiveFunctionVisitor, |
| 39 | visitReactiveFunction, |
| 40 | } from '../ReactiveScopes/visitors'; |
| 41 | import {getOrInsertDefault} from '../Utils/utils'; |
| 42 | |
| 43 | /** |
| 44 | * Validates that all explicit manual memoization (useMemo/useCallback) was accurately |
| 45 | * preserved, and that no originally memoized values became unmemoized in the output. |
| 46 | * |
| 47 | * This can occur if a value's mutable range somehow extended to include a hook and |
| 48 | * was pruned. |
| 49 | */ |
| 50 | export function validatePreservedManualMemoization(fn: ReactiveFunction): void { |
| 51 | const state = { |
| 52 | env: fn.env, |
| 53 | manualMemoState: null, |
| 54 | }; |
| 55 | visitReactiveFunction(fn, new Visitor(), state); |
| 56 | } |
| 57 | |
| 58 | const DEBUG = false; |
| 59 | |
| 60 | type ManualMemoBlockState = { |
| 61 | /** |
| 62 | * Tracks reassigned temporaries. |
| 63 | * This is necessary because useMemo calls are usually inlined. |
| 64 | * Inlining produces a `let` declaration, followed by reassignments |
| 65 | * to the newly declared variable (one per return statement). |
| 66 | * Since InferReactiveScopes does not merge scopes across reassigned |
| 67 | * variables (except in the case of a mutate-after-phi), we need to |
| 68 | * track reassignments to validate we're retaining manual memo. |
| 69 | */ |
| 70 | reassignments: Map<DeclarationId, Set<Identifier>>; |
| 71 | // The source of the original memoization, used when reporting errors |
| 72 | loc: SourceLocation; |
| 73 | |
| 74 | /** |
| 75 | * Values produced within manual memoization blocks. |
| 76 | * We track these to ensure our inferred dependencies are |
| 77 | * produced before the manual memo block starts |
| 78 | * |
| 79 | * As an example: |
| 80 | * ```js |
| 81 | * // source |
| 82 | * const result = useMemo(() => { |
| 83 | * return [makeObject(input1), input2], |
| 84 | * }, [input1, input2]); |
| 85 | * ``` |
| 86 | * Here, we record inferred dependencies as [input1, input2] |
| 87 | * but not t0 |
| 88 | * ```js |
| 89 | * // StartMemoize |
| 90 | * let t0; |
| 91 | * if ($[0] != input1) { |
| 92 | * t0 = makeObject(input1); |
| 93 | * // ... |
| 94 | * } else { ... } |
| 95 | * |
| 96 | * let result; |
| 97 | * if ($[1] != t0 || $[2] != input2) { |
| 98 | * result = [t0, input2]; |
| 99 | * } else { ... } |
| 100 | * ``` |
| 101 | */ |
| 102 | decls: Set<DeclarationId>; |
| 103 | |
| 104 | /* |
| 105 | * normalized depslist from useMemo/useCallback |
| 106 | * callsite in source |
| 107 | */ |
| 108 | depsFromSource: Array<ManualMemoDependency> | null; |
| 109 | manualMemoId: number; |
| 110 | }; |
| 111 | |
| 112 | type VisitorState = { |
| 113 | env: Environment; |
| 114 | manualMemoState: ManualMemoBlockState | null; |
| 115 | }; |
| 116 | |
| 117 | function prettyPrintScopeDependency(val: ReactiveScopeDependency): string { |
| 118 | let rootStr; |
| 119 | if (val.identifier.name?.kind === 'named') { |
| 120 | rootStr = val.identifier.name.value; |
| 121 | } else { |
| 122 | rootStr = '[unnamed]'; |
| 123 | } |
| 124 | return `${rootStr}${val.path.map(v => `${v.optional ? '?.' : '.'}${v.property}`).join('')}`; |
| 125 | } |
| 126 | |
| 127 | enum CompareDependencyResult { |
| 128 | Ok = 0, |
| 129 | RootDifference = 1, |
| 130 | PathDifference = 2, |
| 131 | Subpath = 3, |
| 132 | RefAccessDifference = 4, |
| 133 | } |
| 134 | |
| 135 | function merge( |
| 136 | a: CompareDependencyResult, |
| 137 | b: CompareDependencyResult, |
| 138 | ): CompareDependencyResult { |
| 139 | return Math.max(a, b); |
| 140 | } |
| 141 | |
| 142 | function getCompareDependencyResultDescription( |
| 143 | result: CompareDependencyResult, |
| 144 | ): string { |
| 145 | switch (result) { |
| 146 | case CompareDependencyResult.Ok: |
| 147 | return 'Dependencies equal'; |
| 148 | case CompareDependencyResult.RootDifference: |
| 149 | case CompareDependencyResult.PathDifference: |
| 150 | return 'Inferred different dependency than source'; |
| 151 | case CompareDependencyResult.RefAccessDifference: |
| 152 | return 'Differences in ref.current access'; |
| 153 | case CompareDependencyResult.Subpath: |
| 154 | return 'Inferred less specific property than source'; |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | function compareDeps( |
| 159 | inferred: ManualMemoDependency, |
| 160 | source: ManualMemoDependency, |
| 161 | ): CompareDependencyResult { |
| 162 | const rootsEqual = |
| 163 | (inferred.root.kind === 'Global' && |
| 164 | source.root.kind === 'Global' && |
| 165 | inferred.root.identifierName === source.root.identifierName) || |
| 166 | (inferred.root.kind === 'NamedLocal' && |
| 167 | source.root.kind === 'NamedLocal' && |
| 168 | inferred.root.value.identifier.id === source.root.value.identifier.id); |
| 169 | if (!rootsEqual) { |
| 170 | return CompareDependencyResult.RootDifference; |
| 171 | } |
| 172 | |
| 173 | let isSubpath = true; |
| 174 | for (let i = 0; i < Math.min(inferred.path.length, source.path.length); i++) { |
| 175 | if (inferred.path[i].property !== source.path[i].property) { |
| 176 | isSubpath = false; |
| 177 | break; |
| 178 | } else if (inferred.path[i].optional !== source.path[i].optional) { |
| 179 | /** |
| 180 | * The inferred path must be at least as precise as the manual path: |
| 181 | * if the inferred path is optional, then the source path must have |
| 182 | * been optional too. |
| 183 | */ |
| 184 | return CompareDependencyResult.PathDifference; |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | if ( |
| 189 | isSubpath && |
| 190 | (source.path.length === inferred.path.length || |
| 191 | (inferred.path.length >= source.path.length && |
| 192 | !inferred.path.some(token => token.property === 'current'))) |
| 193 | ) { |
| 194 | return CompareDependencyResult.Ok; |
| 195 | } else { |
| 196 | if (isSubpath) { |
| 197 | if ( |
| 198 | source.path.some(token => token.property === 'current') || |
| 199 | inferred.path.some(token => token.property === 'current') |
| 200 | ) { |
| 201 | return CompareDependencyResult.RefAccessDifference; |
| 202 | } else { |
| 203 | return CompareDependencyResult.Subpath; |
| 204 | } |
| 205 | } else { |
| 206 | return CompareDependencyResult.PathDifference; |
| 207 | } |
| 208 | } |
| 209 | } |
| 210 | |
| 211 | /** |
| 212 | * Validate that an inferred dependency either matches a source dependency |
| 213 | * or is produced by earlier instructions in the same manual memoization |
| 214 | * call. |
| 215 | * Inferred dependency `rootA.[pathA]` matches a source dependency `rootB.[pathB]` |
| 216 | * when: |
| 217 | * - rootA and rootB are loads from the same named identifier. Note that this |
| 218 | * identifier must be also named in source, as DropManualMemoization, which |
| 219 | * runs before any renaming passes, only records loads from named variables. |
| 220 | * - and one of the following holds: |
| 221 | * - pathA and pathB are identifical |
| 222 | * - pathB is a subpath of pathA and neither read into a `ref` type* |
| 223 | * |
| 224 | * We do not allow for partial matches on ref types because they are not immutable |
| 225 | * values, e.g. |
| 226 | * ref_prev === ref_new does not imply ref_prev.current === ref_new.current |
| 227 | */ |
| 228 | function validateInferredDep( |
| 229 | dep: ReactiveScopeDependency, |
| 230 | temporaries: Map<IdentifierId, ManualMemoDependency>, |
| 231 | declsWithinMemoBlock: Set<DeclarationId>, |
| 232 | validDepsInMemoBlock: Array<ManualMemoDependency>, |
| 233 | env: Environment, |
| 234 | memoLocation: SourceLocation, |
| 235 | ): void { |
| 236 | let normalizedDep: ManualMemoDependency; |
| 237 | const maybeNormalizedRoot = temporaries.get(dep.identifier.id); |
| 238 | if (maybeNormalizedRoot != null) { |
| 239 | normalizedDep = { |
| 240 | root: maybeNormalizedRoot.root, |
| 241 | path: [...maybeNormalizedRoot.path, ...dep.path], |
| 242 | loc: maybeNormalizedRoot.loc, |
| 243 | }; |
| 244 | } else { |
| 245 | CompilerError.invariant(dep.identifier.name?.kind === 'named', { |
| 246 | reason: |
| 247 | 'ValidatePreservedManualMemoization: expected scope dependency to be named', |
| 248 | loc: GeneratedSource, |
| 249 | }); |
| 250 | normalizedDep = { |
| 251 | root: { |
| 252 | kind: 'NamedLocal', |
| 253 | value: { |
| 254 | kind: 'Identifier', |
| 255 | identifier: dep.identifier, |
| 256 | loc: GeneratedSource, |
| 257 | effect: Effect.Read, |
| 258 | reactive: false, |
| 259 | }, |
| 260 | constant: false, |
| 261 | }, |
| 262 | path: [...dep.path], |
| 263 | loc: GeneratedSource, |
| 264 | }; |
| 265 | } |
| 266 | for (const decl of declsWithinMemoBlock) { |
| 267 | if ( |
| 268 | normalizedDep.root.kind === 'NamedLocal' && |
| 269 | decl === normalizedDep.root.value.identifier.declarationId |
| 270 | ) { |
| 271 | return; |
| 272 | } |
| 273 | } |
| 274 | let errorDiagnostic: CompareDependencyResult | null = null; |
| 275 | for (const originalDep of validDepsInMemoBlock) { |
| 276 | const compareResult = compareDeps(normalizedDep, originalDep); |
| 277 | if (compareResult === CompareDependencyResult.Ok) { |
| 278 | return; |
| 279 | } else { |
| 280 | errorDiagnostic = merge(errorDiagnostic ?? compareResult, compareResult); |
| 281 | } |
| 282 | } |
| 283 | env.recordError( |
| 284 | CompilerDiagnostic.create({ |
| 285 | category: ErrorCategory.PreserveManualMemo, |
| 286 | reason: 'Existing memoization could not be preserved', |
| 287 | description: [ |
| 288 | 'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. ', |
| 289 | 'The inferred dependencies did not match the manually specified dependencies, which could cause the value to change more or less frequently than expected. ', |
| 290 | DEBUG || |
| 291 | // If the dependency is a named variable then we can report it. Otherwise only print in debug mode |
| 292 | (dep.identifier.name != null && dep.identifier.name.kind === 'named') |
| 293 | ? `The inferred dependency was \`${prettyPrintScopeDependency( |
| 294 | dep, |
| 295 | )}\`, but the source dependencies were [${validDepsInMemoBlock |
| 296 | .map(dep => printManualMemoDependency(dep, true)) |
| 297 | .join(', ')}]. ${ |
| 298 | errorDiagnostic |
| 299 | ? getCompareDependencyResultDescription(errorDiagnostic) |
| 300 | : 'Inferred dependency not present in source' |
| 301 | }` |
| 302 | : '', |
| 303 | ] |
| 304 | .join('') |
| 305 | .trim(), |
| 306 | suggestions: null, |
| 307 | }).withDetails({ |
| 308 | kind: 'error', |
| 309 | loc: memoLocation, |
| 310 | message: 'Could not preserve existing manual memoization', |
| 311 | }), |
| 312 | ); |
| 313 | } |
| 314 | |
| 315 | class Visitor extends ReactiveFunctionVisitor<VisitorState> { |
| 316 | /** |
| 317 | * Records all completed scopes (regardless of transitive memoization |
| 318 | * of scope dependencies) |
| 319 | * |
| 320 | * Both @scopes and @prunedScopes are live sets. We rely on iterating |
| 321 | * the reactive-ir in evaluation order, as they are used to determine |
| 322 | * whether scope dependencies / declarations have completed mutation. |
| 323 | */ |
| 324 | scopes: Set<ScopeId> = new Set(); |
| 325 | prunedScopes: Set<ScopeId> = new Set(); |
| 326 | temporaries: Map<IdentifierId, ManualMemoDependency> = new Map(); |
| 327 | |
| 328 | /** |
| 329 | * Recursively visit values and instructions to collect declarations |
| 330 | * and property loads. |
| 331 | * @returns a @{ManualMemoDependency} representing the variable + |
| 332 | * property reads represented by @value |
| 333 | */ |
| 334 | recordDepsInValue(value: ReactiveValue, state: VisitorState): void { |
| 335 | switch (value.kind) { |
| 336 | case 'SequenceExpression': { |
| 337 | for (const instr of value.instructions) { |
| 338 | this.visitInstruction(instr, state); |
| 339 | } |
| 340 | this.recordDepsInValue(value.value, state); |
| 341 | break; |
| 342 | } |
| 343 | case 'OptionalExpression': { |
| 344 | this.recordDepsInValue(value.value, state); |
| 345 | break; |
| 346 | } |
| 347 | case 'ConditionalExpression': { |
| 348 | this.recordDepsInValue(value.test, state); |
| 349 | this.recordDepsInValue(value.consequent, state); |
| 350 | this.recordDepsInValue(value.alternate, state); |
| 351 | break; |
| 352 | } |
| 353 | case 'LogicalExpression': { |
| 354 | this.recordDepsInValue(value.left, state); |
| 355 | this.recordDepsInValue(value.right, state); |
| 356 | break; |
| 357 | } |
| 358 | default: { |
| 359 | collectMaybeMemoDependencies(value, this.temporaries, false); |
| 360 | if ( |
| 361 | value.kind === 'StoreLocal' || |
| 362 | value.kind === 'StoreContext' || |
| 363 | value.kind === 'Destructure' |
| 364 | ) { |
| 365 | for (const storeTarget of eachInstructionValueLValue(value)) { |
| 366 | state.manualMemoState?.decls.add( |
| 367 | storeTarget.identifier.declarationId, |
| 368 | ); |
| 369 | if (storeTarget.identifier.name?.kind === 'named') { |
| 370 | this.temporaries.set(storeTarget.identifier.id, { |
| 371 | root: { |
| 372 | kind: 'NamedLocal', |
| 373 | value: storeTarget, |
| 374 | constant: false, |
| 375 | }, |
| 376 | path: [], |
| 377 | loc: storeTarget.loc, |
| 378 | }); |
| 379 | } |
| 380 | } |
| 381 | } |
| 382 | break; |
| 383 | } |
| 384 | } |
| 385 | } |
| 386 | |
| 387 | recordTemporaries(instr: ReactiveInstruction, state: VisitorState): void { |
| 388 | const temporaries = this.temporaries; |
| 389 | const {lvalue, value} = instr; |
| 390 | const lvalId = lvalue?.identifier.id; |
| 391 | if (lvalId != null && temporaries.has(lvalId)) { |
| 392 | return; |
| 393 | } |
| 394 | const isNamedLocal = lvalue?.identifier.name?.kind === 'named'; |
| 395 | if (lvalue !== null && isNamedLocal && state.manualMemoState != null) { |
| 396 | state.manualMemoState.decls.add(lvalue.identifier.declarationId); |
| 397 | } |
| 398 | |
| 399 | this.recordDepsInValue(value, state); |
| 400 | if (lvalue != null) { |
| 401 | temporaries.set(lvalue.identifier.id, { |
| 402 | root: { |
| 403 | kind: 'NamedLocal', |
| 404 | value: {...lvalue}, |
| 405 | constant: false, |
| 406 | }, |
| 407 | path: [], |
| 408 | loc: lvalue.loc, |
| 409 | }); |
| 410 | } |
| 411 | } |
| 412 | |
| 413 | override visitScope( |
| 414 | scopeBlock: ReactiveScopeBlock, |
| 415 | state: VisitorState, |
| 416 | ): void { |
| 417 | this.traverseScope(scopeBlock, state); |
| 418 | |
| 419 | if ( |
| 420 | state.manualMemoState != null && |
| 421 | state.manualMemoState.depsFromSource != null |
| 422 | ) { |
| 423 | for (const dep of scopeBlock.scope.dependencies) { |
| 424 | validateInferredDep( |
| 425 | dep, |
| 426 | this.temporaries, |
| 427 | state.manualMemoState.decls, |
| 428 | state.manualMemoState.depsFromSource, |
| 429 | state.env, |
| 430 | state.manualMemoState.loc, |
| 431 | ); |
| 432 | } |
| 433 | } |
| 434 | |
| 435 | this.scopes.add(scopeBlock.scope.id); |
| 436 | for (const id of scopeBlock.scope.merged) { |
| 437 | this.scopes.add(id); |
| 438 | } |
| 439 | } |
| 440 | |
| 441 | override visitPrunedScope( |
| 442 | scopeBlock: PrunedReactiveScopeBlock, |
| 443 | state: VisitorState, |
| 444 | ): void { |
| 445 | this.traversePrunedScope(scopeBlock, state); |
| 446 | this.prunedScopes.add(scopeBlock.scope.id); |
| 447 | } |
| 448 | |
| 449 | override visitInstruction( |
| 450 | instruction: ReactiveInstruction, |
| 451 | state: VisitorState, |
| 452 | ): void { |
| 453 | /** |
| 454 | * We don't invoke traverseInstructions because `recordDepsInValue` |
| 455 | * recursively visits ReactiveValues and instructions |
| 456 | */ |
| 457 | this.recordTemporaries(instruction, state); |
| 458 | const value = instruction.value; |
| 459 | // Track reassignments from inlining of manual memo |
| 460 | if ( |
| 461 | value.kind === 'StoreLocal' && |
| 462 | value.lvalue.kind === 'Reassign' && |
| 463 | state.manualMemoState != null |
| 464 | ) { |
| 465 | // Complex cases of inlining end up with a temporary that is reassigned |
| 466 | const ids = getOrInsertDefault( |
| 467 | state.manualMemoState.reassignments, |
| 468 | value.lvalue.place.identifier.declarationId, |
| 469 | new Set(), |
| 470 | ); |
| 471 | ids.add(value.value.identifier); |
| 472 | } |
| 473 | if ( |
| 474 | value.kind === 'LoadLocal' && |
| 475 | value.place.identifier.scope != null && |
| 476 | instruction.lvalue != null && |
| 477 | instruction.lvalue.identifier.scope == null && |
| 478 | state.manualMemoState != null |
| 479 | ) { |
| 480 | // Simpler cases of inlining assign to the original IIFE lvalue |
| 481 | const ids = getOrInsertDefault( |
| 482 | state.manualMemoState.reassignments, |
| 483 | instruction.lvalue.identifier.declarationId, |
| 484 | new Set(), |
| 485 | ); |
| 486 | ids.add(value.place.identifier); |
| 487 | } |
| 488 | if (value.kind === 'StartMemoize') { |
| 489 | CompilerError.invariant(state.manualMemoState == null, { |
| 490 | reason: 'Unexpected nested StartMemoize instructions', |
| 491 | description: `Bad manual memoization ids: ${state.manualMemoState?.manualMemoId}, ${value.manualMemoId}`, |
| 492 | loc: value.loc, |
| 493 | }); |
| 494 | |
| 495 | if (value.hasInvalidDeps === true) { |
| 496 | /* |
| 497 | * ValidateExhaustiveDependencies already reported an error for this |
| 498 | * memo block, skip validation to avoid duplicate errors |
| 499 | */ |
| 500 | return; |
| 501 | } |
| 502 | |
| 503 | let depsFromSource: Array<ManualMemoDependency> | null = null; |
| 504 | if (value.deps != null) { |
| 505 | depsFromSource = value.deps; |
| 506 | } |
| 507 | |
| 508 | state.manualMemoState = { |
| 509 | loc: instruction.loc, |
| 510 | decls: new Set(), |
| 511 | depsFromSource, |
| 512 | manualMemoId: value.manualMemoId, |
| 513 | reassignments: new Map(), |
| 514 | }; |
| 515 | |
| 516 | /** |
| 517 | * We check that each scope dependency is either: |
| 518 | * (1) Not scoped |
| 519 | * Checking `identifier.scope == null` is a proxy for whether the dep |
| 520 | * is a primitive, global, or other guaranteed non-allocating value. |
| 521 | * Non-allocating values do not need memoization. |
| 522 | * Note that this is a conservative estimate as some primitive-typed |
| 523 | * variables do receive scopes. |
| 524 | * (2) Scoped (a maybe newly-allocated value with a mutable range) |
| 525 | * Here, we check that the dependency's scope has completed before |
| 526 | * the manual useMemo as a proxy for mutable-range checking. This |
| 527 | * validates that there are no potential rule-of-react violations |
| 528 | * in source. |
| 529 | * Note that scope range is an overly conservative proxy as we merge |
| 530 | * overlapping ranges. |
| 531 | * See fixture `error.false-positive-useMemo-overlap-scopes` |
| 532 | */ |
| 533 | for (const {identifier, loc} of eachInstructionValueOperand( |
| 534 | value as InstructionValue, |
| 535 | )) { |
| 536 | if ( |
| 537 | identifier.scope != null && |
| 538 | !this.scopes.has(identifier.scope.id) && |
| 539 | !this.prunedScopes.has(identifier.scope.id) |
| 540 | ) { |
| 541 | state.env.recordError( |
| 542 | CompilerDiagnostic.create({ |
| 543 | category: ErrorCategory.PreserveManualMemo, |
| 544 | reason: 'Existing memoization could not be preserved', |
| 545 | description: [ |
| 546 | 'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. ', |
| 547 | 'This dependency may be mutated later, which could cause the value to change unexpectedly', |
| 548 | ].join(''), |
| 549 | }).withDetails({ |
| 550 | kind: 'error', |
| 551 | loc, |
| 552 | message: 'This dependency may be modified later', |
| 553 | }), |
| 554 | ); |
| 555 | } |
| 556 | } |
| 557 | } |
| 558 | if (value.kind === 'FinishMemoize') { |
| 559 | if (state.manualMemoState == null) { |
| 560 | // StartMemoize had invalid deps, skip validation |
| 561 | return; |
| 562 | } |
| 563 | CompilerError.invariant( |
| 564 | state.manualMemoState.manualMemoId === value.manualMemoId, |
| 565 | { |
| 566 | reason: 'Unexpected mismatch between StartMemoize and FinishMemoize', |
| 567 | description: `Encountered StartMemoize id=${state.manualMemoState.manualMemoId} followed by FinishMemoize id=${value.manualMemoId}`, |
| 568 | loc: value.loc, |
| 569 | }, |
| 570 | ); |
| 571 | const reassignments = state.manualMemoState.reassignments; |
| 572 | state.manualMemoState = null; |
| 573 | if (!value.pruned) { |
| 574 | for (const {identifier, loc} of eachInstructionValueOperand( |
| 575 | value as InstructionValue, |
| 576 | )) { |
| 577 | let decls; |
| 578 | if (identifier.scope == null) { |
| 579 | /** |
| 580 | * If the manual memo was a useMemo that got inlined, iterate through |
| 581 | * all reassignments to the iife temporary to ensure they're memoized. |
| 582 | */ |
| 583 | decls = reassignments.get(identifier.declarationId) ?? [identifier]; |
| 584 | } else { |
| 585 | decls = [identifier]; |
| 586 | } |
| 587 | |
| 588 | for (const identifier of decls) { |
| 589 | if (isUnmemoized(identifier, this.scopes)) { |
| 590 | state.env.recordError( |
| 591 | CompilerDiagnostic.create({ |
| 592 | category: ErrorCategory.PreserveManualMemo, |
| 593 | reason: 'Existing memoization could not be preserved', |
| 594 | description: [ |
| 595 | 'React Compiler has skipped optimizing this component because the existing manual memoization could not be preserved. This value was memoized in source but not in compilation output', |
| 596 | DEBUG |
| 597 | ? `${printIdentifier(identifier)} was not memoized.` |
| 598 | : '', |
| 599 | ] |
| 600 | .join('') |
| 601 | .trim(), |
| 602 | }).withDetails({ |
| 603 | kind: 'error', |
| 604 | loc, |
| 605 | message: 'Could not preserve existing memoization', |
| 606 | }), |
| 607 | ); |
| 608 | } |
| 609 | } |
| 610 | } |
| 611 | } |
| 612 | } |
| 613 | } |
| 614 | } |
| 615 | |
| 616 | function isUnmemoized(operand: Identifier, scopes: Set<ScopeId>): boolean { |
| 617 | return operand.scope != null && !scopes.has(operand.scope.id); |
| 618 | } |