| 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 {CompilerDiagnostic, CompilerError, SourceLocation} from '..'; |
| 9 | import {ErrorCategory} from '../CompilerError'; |
| 10 | import { |
| 11 | CallExpression, |
| 12 | Effect, |
| 13 | Environment, |
| 14 | FinishMemoize, |
| 15 | FunctionExpression, |
| 16 | HIRFunction, |
| 17 | IdentifierId, |
| 18 | Instruction, |
| 19 | InstructionId, |
| 20 | InstructionValue, |
| 21 | LoadGlobal, |
| 22 | LoadLocal, |
| 23 | ManualMemoDependency, |
| 24 | MethodCall, |
| 25 | Place, |
| 26 | PropertyLoad, |
| 27 | SpreadPattern, |
| 28 | StartMemoize, |
| 29 | TInstruction, |
| 30 | getHookKindForType, |
| 31 | makeInstructionId, |
| 32 | } from '../HIR'; |
| 33 | import {createTemporaryPlace, markInstructionIds} from '../HIR/HIRBuilder'; |
| 34 | |
| 35 | type ManualMemoCallee = { |
| 36 | kind: 'useMemo' | 'useCallback'; |
| 37 | loadInstr: TInstruction<LoadGlobal> | TInstruction<PropertyLoad>; |
| 38 | }; |
| 39 | |
| 40 | type IdentifierSidemap = { |
| 41 | functions: Map<IdentifierId, TInstruction<FunctionExpression>>; |
| 42 | manualMemos: Map<IdentifierId, ManualMemoCallee>; |
| 43 | react: Set<IdentifierId>; |
| 44 | maybeDepsLists: Map<IdentifierId, {loc: SourceLocation; deps: Array<Place>}>; |
| 45 | maybeDeps: Map<IdentifierId, ManualMemoDependency>; |
| 46 | optionals: Set<IdentifierId>; |
| 47 | }; |
| 48 | |
| 49 | /** |
| 50 | * Collect loads from named variables and property reads from @value |
| 51 | * into `maybeDeps` |
| 52 | * Returns the variable + property reads represented by @instr |
| 53 | */ |
| 54 | export function collectMaybeMemoDependencies( |
| 55 | value: InstructionValue, |
| 56 | maybeDeps: Map<IdentifierId, ManualMemoDependency>, |
| 57 | optional: boolean, |
| 58 | ): ManualMemoDependency | null { |
| 59 | switch (value.kind) { |
| 60 | case 'LoadGlobal': { |
| 61 | return { |
| 62 | root: { |
| 63 | kind: 'Global', |
| 64 | identifierName: value.binding.name, |
| 65 | }, |
| 66 | path: [], |
| 67 | loc: value.loc, |
| 68 | }; |
| 69 | } |
| 70 | case 'PropertyLoad': { |
| 71 | const object = maybeDeps.get(value.object.identifier.id); |
| 72 | if (object != null) { |
| 73 | return { |
| 74 | root: object.root, |
| 75 | // TODO: determine if the access is optional |
| 76 | path: [ |
| 77 | ...object.path, |
| 78 | {property: value.property, optional, loc: value.loc}, |
| 79 | ], |
| 80 | loc: value.loc, |
| 81 | }; |
| 82 | } |
| 83 | break; |
| 84 | } |
| 85 | |
| 86 | case 'LoadLocal': |
| 87 | case 'LoadContext': { |
| 88 | const source = maybeDeps.get(value.place.identifier.id); |
| 89 | if (source != null) { |
| 90 | return source; |
| 91 | } else if ( |
| 92 | value.place.identifier.name != null && |
| 93 | value.place.identifier.name.kind === 'named' |
| 94 | ) { |
| 95 | return { |
| 96 | root: { |
| 97 | kind: 'NamedLocal', |
| 98 | value: {...value.place}, |
| 99 | constant: false, |
| 100 | }, |
| 101 | path: [], |
| 102 | loc: value.place.loc, |
| 103 | }; |
| 104 | } |
| 105 | break; |
| 106 | } |
| 107 | case 'StoreLocal': { |
| 108 | /* |
| 109 | * Value blocks rely on StoreLocal to populate their return value. |
| 110 | * We need to track these as optional property chains are valid in |
| 111 | * source depslists |
| 112 | */ |
| 113 | const lvalue = value.lvalue.place.identifier; |
| 114 | const rvalue = value.value.identifier.id; |
| 115 | const aliased = maybeDeps.get(rvalue); |
| 116 | if (aliased != null && lvalue.name?.kind !== 'named') { |
| 117 | maybeDeps.set(lvalue.id, aliased); |
| 118 | return aliased; |
| 119 | } |
| 120 | break; |
| 121 | } |
| 122 | } |
| 123 | return null; |
| 124 | } |
| 125 | |
| 126 | function collectTemporaries( |
| 127 | instr: Instruction, |
| 128 | env: Environment, |
| 129 | sidemap: IdentifierSidemap, |
| 130 | ): void { |
| 131 | const {value, lvalue} = instr; |
| 132 | switch (value.kind) { |
| 133 | case 'FunctionExpression': { |
| 134 | sidemap.functions.set( |
| 135 | instr.lvalue.identifier.id, |
| 136 | instr as TInstruction<FunctionExpression>, |
| 137 | ); |
| 138 | break; |
| 139 | } |
| 140 | case 'LoadGlobal': { |
| 141 | const global = env.getGlobalDeclaration(value.binding, value.loc); |
| 142 | const hookKind = global !== null ? getHookKindForType(env, global) : null; |
| 143 | const lvalId = instr.lvalue.identifier.id; |
| 144 | if (hookKind === 'useMemo' || hookKind === 'useCallback') { |
| 145 | sidemap.manualMemos.set(lvalId, { |
| 146 | kind: hookKind, |
| 147 | loadInstr: instr as TInstruction<LoadGlobal>, |
| 148 | }); |
| 149 | } else if (value.binding.name === 'React') { |
| 150 | sidemap.react.add(lvalId); |
| 151 | } |
| 152 | break; |
| 153 | } |
| 154 | case 'PropertyLoad': { |
| 155 | if (sidemap.react.has(value.object.identifier.id)) { |
| 156 | const property = value.property; |
| 157 | if (property === 'useMemo' || property === 'useCallback') { |
| 158 | sidemap.manualMemos.set(instr.lvalue.identifier.id, { |
| 159 | kind: property as 'useMemo' | 'useCallback', |
| 160 | loadInstr: instr as TInstruction<PropertyLoad>, |
| 161 | }); |
| 162 | } |
| 163 | } |
| 164 | break; |
| 165 | } |
| 166 | case 'ArrayExpression': { |
| 167 | if (value.elements.every(e => e.kind === 'Identifier')) { |
| 168 | sidemap.maybeDepsLists.set(instr.lvalue.identifier.id, { |
| 169 | loc: value.loc, |
| 170 | deps: value.elements as Array<Place>, |
| 171 | }); |
| 172 | } |
| 173 | break; |
| 174 | } |
| 175 | } |
| 176 | const maybeDep = collectMaybeMemoDependencies( |
| 177 | value, |
| 178 | sidemap.maybeDeps, |
| 179 | sidemap.optionals.has(lvalue.identifier.id), |
| 180 | ); |
| 181 | // We don't expect named lvalues during this pass (unlike ValidatePreservingManualMemo) |
| 182 | if (maybeDep != null) { |
| 183 | sidemap.maybeDeps.set(lvalue.identifier.id, maybeDep); |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | function makeManualMemoizationMarkers( |
| 188 | fnExpr: Place, |
| 189 | env: Environment, |
| 190 | depsList: Array<ManualMemoDependency> | null, |
| 191 | depsLoc: SourceLocation | null, |
| 192 | memoDecl: Place, |
| 193 | manualMemoId: number, |
| 194 | ): [TInstruction<StartMemoize>, TInstruction<FinishMemoize>] { |
| 195 | return [ |
| 196 | { |
| 197 | id: makeInstructionId(0), |
| 198 | lvalue: createTemporaryPlace(env, fnExpr.loc), |
| 199 | value: { |
| 200 | kind: 'StartMemoize', |
| 201 | manualMemoId, |
| 202 | /* |
| 203 | * Use deps list from source instead of inferred deps |
| 204 | * as dependencies |
| 205 | */ |
| 206 | deps: depsList, |
| 207 | depsLoc, |
| 208 | loc: fnExpr.loc, |
| 209 | }, |
| 210 | effects: null, |
| 211 | loc: fnExpr.loc, |
| 212 | }, |
| 213 | { |
| 214 | id: makeInstructionId(0), |
| 215 | lvalue: createTemporaryPlace(env, fnExpr.loc), |
| 216 | value: { |
| 217 | kind: 'FinishMemoize', |
| 218 | manualMemoId, |
| 219 | decl: {...memoDecl}, |
| 220 | loc: fnExpr.loc, |
| 221 | }, |
| 222 | effects: null, |
| 223 | loc: fnExpr.loc, |
| 224 | }, |
| 225 | ]; |
| 226 | } |
| 227 | |
| 228 | function getManualMemoizationReplacement( |
| 229 | fn: Place, |
| 230 | loc: SourceLocation, |
| 231 | kind: 'useMemo' | 'useCallback', |
| 232 | ): LoadLocal | CallExpression { |
| 233 | if (kind === 'useMemo') { |
| 234 | /* |
| 235 | * Replace the hook callee with the fn arg. |
| 236 | * |
| 237 | * before: |
| 238 | * $1 = LoadGlobal useMemo // load the useMemo global |
| 239 | * $2 = FunctionExpression ... // memo function |
| 240 | * $3 = ArrayExpression [ ... ] // deps array |
| 241 | * $4 = Call $1 ($2, $3 ) // invoke useMemo w fn and deps |
| 242 | * |
| 243 | * after: |
| 244 | * $1 = LoadGlobal useMemo // load the useMemo global (dead code) |
| 245 | * $2 = FunctionExpression ... // memo function |
| 246 | * $3 = ArrayExpression [ ... ] // deps array (dead code) |
| 247 | * $4 = Call $2 () // invoke the memo function itself |
| 248 | * |
| 249 | * Note that a later pass (InlineImmediatelyInvokedFunctionExpressions) will |
| 250 | * inline the useMemo callback along with any other immediately invoked IIFEs. |
| 251 | */ |
| 252 | return { |
| 253 | kind: 'CallExpression', |
| 254 | callee: fn, |
| 255 | /* |
| 256 | * Drop the args, including the deps array which DCE will remove |
| 257 | * later. |
| 258 | */ |
| 259 | args: [], |
| 260 | loc, |
| 261 | }; |
| 262 | } else { |
| 263 | /* |
| 264 | * Instead of a Call, just alias the callback directly. |
| 265 | * |
| 266 | * before: |
| 267 | * $1 = LoadGlobal useCallback |
| 268 | * $2 = FunctionExpression ... // the callback being memoized |
| 269 | * $3 = ArrayExpression ... // deps array |
| 270 | * $4 = Call $1 ( $2, $3 ) // invoke useCallback |
| 271 | * |
| 272 | * after: |
| 273 | * $1 = LoadGlobal useCallback // dead code |
| 274 | * $2 = FunctionExpression ... // the callback being memoized |
| 275 | * $3 = ArrayExpression ... // deps array (dead code) |
| 276 | * $4 = LoadLocal $2 // reference the function |
| 277 | */ |
| 278 | return { |
| 279 | kind: 'LoadLocal', |
| 280 | place: { |
| 281 | kind: 'Identifier', |
| 282 | identifier: fn.identifier, |
| 283 | effect: Effect.Unknown, |
| 284 | reactive: false, |
| 285 | loc, |
| 286 | }, |
| 287 | loc, |
| 288 | }; |
| 289 | } |
| 290 | } |
| 291 | |
| 292 | function extractManualMemoizationArgs( |
| 293 | instr: TInstruction<CallExpression> | TInstruction<MethodCall>, |
| 294 | kind: 'useCallback' | 'useMemo', |
| 295 | sidemap: IdentifierSidemap, |
| 296 | env: Environment, |
| 297 | ): { |
| 298 | fnPlace: Place; |
| 299 | depsList: Array<ManualMemoDependency> | null; |
| 300 | depsLoc: SourceLocation | null; |
| 301 | } | null { |
| 302 | const [fnPlace, depsListPlace] = instr.value.args as Array< |
| 303 | Place | SpreadPattern | undefined |
| 304 | >; |
| 305 | if (fnPlace == null || fnPlace.kind !== 'Identifier') { |
| 306 | env.recordError( |
| 307 | CompilerDiagnostic.create({ |
| 308 | category: ErrorCategory.UseMemo, |
| 309 | reason: `Expected a callback function to be passed to ${kind}`, |
| 310 | description: |
| 311 | kind === 'useCallback' |
| 312 | ? 'The first argument to useCallback() must be a function to cache' |
| 313 | : 'The first argument to useMemo() must be a function that calculates a result to cache', |
| 314 | suggestions: null, |
| 315 | }).withDetails({ |
| 316 | kind: 'error', |
| 317 | loc: instr.value.loc, |
| 318 | message: |
| 319 | kind === 'useCallback' |
| 320 | ? `Expected a callback function` |
| 321 | : `Expected a memoization function`, |
| 322 | }), |
| 323 | ); |
| 324 | return null; |
| 325 | } |
| 326 | if (depsListPlace == null) { |
| 327 | return { |
| 328 | fnPlace, |
| 329 | depsList: null, |
| 330 | depsLoc: null, |
| 331 | }; |
| 332 | } |
| 333 | const maybeDepsList = |
| 334 | depsListPlace.kind === 'Identifier' |
| 335 | ? sidemap.maybeDepsLists.get(depsListPlace.identifier.id) |
| 336 | : null; |
| 337 | if (maybeDepsList == null) { |
| 338 | env.recordError( |
| 339 | CompilerDiagnostic.create({ |
| 340 | category: ErrorCategory.UseMemo, |
| 341 | reason: `Expected the dependency list for ${kind} to be an array literal`, |
| 342 | description: `Expected the dependency list for ${kind} to be an array literal`, |
| 343 | suggestions: null, |
| 344 | }).withDetails({ |
| 345 | kind: 'error', |
| 346 | loc: |
| 347 | depsListPlace?.kind === 'Identifier' ? depsListPlace.loc : instr.loc, |
| 348 | message: `Expected the dependency list for ${kind} to be an array literal`, |
| 349 | }), |
| 350 | ); |
| 351 | return null; |
| 352 | } |
| 353 | const depsList: Array<ManualMemoDependency> = []; |
| 354 | for (const dep of maybeDepsList.deps) { |
| 355 | const maybeDep = sidemap.maybeDeps.get(dep.identifier.id); |
| 356 | if (maybeDep == null) { |
| 357 | env.recordError( |
| 358 | CompilerDiagnostic.create({ |
| 359 | category: ErrorCategory.UseMemo, |
| 360 | reason: `Expected the dependency list to be an array of simple expressions (e.g. \`x\`, \`x.y.z\`, \`x?.y?.z\`)`, |
| 361 | description: `Expected the dependency list to be an array of simple expressions (e.g. \`x\`, \`x.y.z\`, \`x?.y?.z\`)`, |
| 362 | suggestions: null, |
| 363 | }).withDetails({ |
| 364 | kind: 'error', |
| 365 | loc: dep.loc, |
| 366 | message: `Expected the dependency list to be an array of simple expressions (e.g. \`x\`, \`x.y.z\`, \`x?.y?.z\`)`, |
| 367 | }), |
| 368 | ); |
| 369 | } else { |
| 370 | depsList.push(maybeDep); |
| 371 | } |
| 372 | } |
| 373 | return { |
| 374 | fnPlace, |
| 375 | depsList, |
| 376 | depsLoc: maybeDepsList.loc, |
| 377 | }; |
| 378 | } |
| 379 | |
| 380 | /* |
| 381 | * Removes manual memoization using the `useMemo` and `useCallback` APIs. This pass is designed |
| 382 | * to compose with InlineImmediatelyInvokedFunctionExpressions, and needs to run prior to entering |
| 383 | * SSA form (alternatively we could refactor and re-EnterSSA after inlining). Therefore it cannot |
| 384 | * rely on type inference to find useMemo/useCallback invocations, and instead does basic tracking |
| 385 | * of globals and property loads to find both direct calls as well as usage via the React namespace, |
| 386 | * eg `React.useMemo()`. |
| 387 | * |
| 388 | * This pass also validates that useMemo callbacks return a value (not void), ensuring that useMemo |
| 389 | * is only used for memoizing values and not for running arbitrary side effects. |
| 390 | */ |
| 391 | export function dropManualMemoization(func: HIRFunction): void { |
| 392 | const isValidationEnabled = |
| 393 | func.env.config.validatePreserveExistingMemoizationGuarantees || |
| 394 | func.env.config.validateNoSetStateInRender || |
| 395 | func.env.config.enablePreserveExistingMemoizationGuarantees; |
| 396 | const optionals = findOptionalPlaces(func); |
| 397 | const sidemap: IdentifierSidemap = { |
| 398 | functions: new Map(), |
| 399 | manualMemos: new Map(), |
| 400 | react: new Set(), |
| 401 | maybeDeps: new Map(), |
| 402 | maybeDepsLists: new Map(), |
| 403 | optionals, |
| 404 | }; |
| 405 | let nextManualMemoId = 0; |
| 406 | |
| 407 | /** |
| 408 | * Phase 1: |
| 409 | * - Overwrite manual memoization from |
| 410 | * CallExpression callee="useMemo/Callback", args=[fnArg, depslist]) |
| 411 | * to either |
| 412 | * CallExpression callee=fnArg |
| 413 | * LoadLocal fnArg |
| 414 | * - (if validation is enabled) collect manual memoization markers |
| 415 | */ |
| 416 | const queuedInserts: Map< |
| 417 | InstructionId, |
| 418 | TInstruction<StartMemoize> | TInstruction<FinishMemoize> |
| 419 | > = new Map(); |
| 420 | for (const [_, block] of func.body.blocks) { |
| 421 | for (let i = 0; i < block.instructions.length; i++) { |
| 422 | const instr = block.instructions[i]!; |
| 423 | if ( |
| 424 | instr.value.kind === 'CallExpression' || |
| 425 | instr.value.kind === 'MethodCall' |
| 426 | ) { |
| 427 | const id = |
| 428 | instr.value.kind === 'CallExpression' |
| 429 | ? instr.value.callee.identifier.id |
| 430 | : instr.value.property.identifier.id; |
| 431 | |
| 432 | const manualMemo = sidemap.manualMemos.get(id); |
| 433 | if (manualMemo != null) { |
| 434 | const memoDetails = extractManualMemoizationArgs( |
| 435 | instr as TInstruction<CallExpression> | TInstruction<MethodCall>, |
| 436 | manualMemo.kind, |
| 437 | sidemap, |
| 438 | func.env, |
| 439 | ); |
| 440 | |
| 441 | if (memoDetails == null) { |
| 442 | continue; |
| 443 | } |
| 444 | const {fnPlace, depsList, depsLoc} = memoDetails; |
| 445 | |
| 446 | instr.value = getManualMemoizationReplacement( |
| 447 | fnPlace, |
| 448 | instr.value.loc, |
| 449 | manualMemo.kind, |
| 450 | ); |
| 451 | if (isValidationEnabled) { |
| 452 | /** |
| 453 | * Explicitly bail out when we encounter manual memoization |
| 454 | * without inline instructions, as our current validation |
| 455 | * assumes that source depslists closely match inferred deps |
| 456 | * due to the `exhaustive-deps` lint rule (which only provides |
| 457 | * diagnostics for inline memo functions) |
| 458 | * ```js |
| 459 | * useMemo(opaqueFn, [dep1, dep2]); |
| 460 | * ``` |
| 461 | * While we could handle this by diffing reactive scope deps |
| 462 | * of the opaque arg against the source depslist, this pattern |
| 463 | * is rare and likely sketchy. |
| 464 | */ |
| 465 | if (!sidemap.functions.has(fnPlace.identifier.id)) { |
| 466 | func.env.recordError( |
| 467 | CompilerDiagnostic.create({ |
| 468 | category: ErrorCategory.UseMemo, |
| 469 | reason: `Expected the first argument to be an inline function expression`, |
| 470 | description: `Expected the first argument to be an inline function expression`, |
| 471 | suggestions: [], |
| 472 | }).withDetails({ |
| 473 | kind: 'error', |
| 474 | loc: fnPlace.loc, |
| 475 | message: `Expected the first argument to be an inline function expression`, |
| 476 | }), |
| 477 | ); |
| 478 | continue; |
| 479 | } |
| 480 | const memoDecl: Place = |
| 481 | manualMemo.kind === 'useMemo' |
| 482 | ? instr.lvalue |
| 483 | : { |
| 484 | kind: 'Identifier', |
| 485 | identifier: fnPlace.identifier, |
| 486 | effect: Effect.Unknown, |
| 487 | reactive: false, |
| 488 | loc: fnPlace.loc, |
| 489 | }; |
| 490 | |
| 491 | const [startMarker, finishMarker] = makeManualMemoizationMarkers( |
| 492 | fnPlace, |
| 493 | func.env, |
| 494 | depsList, |
| 495 | depsLoc, |
| 496 | memoDecl, |
| 497 | nextManualMemoId++, |
| 498 | ); |
| 499 | |
| 500 | /** |
| 501 | * Insert StartMarker right after the `useMemo`/`useCallback` load to |
| 502 | * ensure all temporaries created when lowering the inline fn expression |
| 503 | * are included. |
| 504 | * e.g. |
| 505 | * ``` |
| 506 | * 0: LoadGlobal useMemo |
| 507 | * 1: StartMarker deps=[var] |
| 508 | * 2: t0 = LoadContext [var] |
| 509 | * 3: function deps=t0 |
| 510 | * ... |
| 511 | * ``` |
| 512 | */ |
| 513 | queuedInserts.set(manualMemo.loadInstr.id, startMarker); |
| 514 | queuedInserts.set(instr.id, finishMarker); |
| 515 | } |
| 516 | } |
| 517 | } else { |
| 518 | collectTemporaries(instr, func.env, sidemap); |
| 519 | } |
| 520 | } |
| 521 | } |
| 522 | |
| 523 | /** |
| 524 | * Phase 2: Insert manual memoization markers as needed |
| 525 | */ |
| 526 | if (queuedInserts.size > 0) { |
| 527 | let hasChanges = false; |
| 528 | for (const [_, block] of func.body.blocks) { |
| 529 | let nextInstructions: Array<Instruction> | null = null; |
| 530 | for (let i = 0; i < block.instructions.length; i++) { |
| 531 | const instr = block.instructions[i]; |
| 532 | const insertInstr = queuedInserts.get(instr.id); |
| 533 | if (insertInstr != null) { |
| 534 | nextInstructions = nextInstructions ?? block.instructions.slice(0, i); |
| 535 | nextInstructions.push(instr); |
| 536 | nextInstructions.push(insertInstr); |
| 537 | } else if (nextInstructions != null) { |
| 538 | nextInstructions.push(instr); |
| 539 | } |
| 540 | } |
| 541 | if (nextInstructions !== null) { |
| 542 | block.instructions = nextInstructions; |
| 543 | hasChanges = true; |
| 544 | } |
| 545 | } |
| 546 | |
| 547 | if (hasChanges) { |
| 548 | markInstructionIds(func.body); |
| 549 | } |
| 550 | } |
| 551 | } |
| 552 | |
| 553 | function findOptionalPlaces(fn: HIRFunction): Set<IdentifierId> { |
| 554 | const optionals = new Set<IdentifierId>(); |
| 555 | for (const [, block] of fn.body.blocks) { |
| 556 | if (block.terminal.kind === 'optional' && block.terminal.optional) { |
| 557 | const optionalTerminal = block.terminal; |
| 558 | let testBlock = fn.body.blocks.get(block.terminal.test)!; |
| 559 | loop: while (true) { |
| 560 | const terminal = testBlock.terminal; |
| 561 | switch (terminal.kind) { |
| 562 | case 'branch': { |
| 563 | if (terminal.fallthrough === optionalTerminal.fallthrough) { |
| 564 | // found it |
| 565 | const consequent = fn.body.blocks.get(terminal.consequent)!; |
| 566 | const last = consequent.instructions.at(-1); |
| 567 | if (last !== undefined && last.value.kind === 'StoreLocal') { |
| 568 | optionals.add(last.value.value.identifier.id); |
| 569 | } |
| 570 | break loop; |
| 571 | } else { |
| 572 | testBlock = fn.body.blocks.get(terminal.fallthrough)!; |
| 573 | } |
| 574 | break; |
| 575 | } |
| 576 | case 'optional': |
| 577 | case 'logical': |
| 578 | case 'sequence': |
| 579 | case 'ternary': { |
| 580 | testBlock = fn.body.blocks.get(terminal.fallthrough)!; |
| 581 | break; |
| 582 | } |
| 583 | case 'maybe-throw': { |
| 584 | testBlock = fn.body.blocks.get(terminal.continuation)!; |
| 585 | break; |
| 586 | } |
| 587 | default: { |
| 588 | CompilerError.invariant(false, { |
| 589 | reason: `Unexpected terminal in optional`, |
| 590 | message: `Unexpected ${terminal.kind} in optional`, |
| 591 | loc: terminal.loc, |
| 592 | }); |
| 593 | } |
| 594 | } |
| 595 | } |
| 596 | } |
| 597 | } |
| 598 | return optionals; |
| 599 | } |