diff --git a/packages/compiler/src/frontend/type-mapper.ts b/packages/compiler/src/frontend/type-mapper.ts index 1e3954586e..7a40d4e249 100644 --- a/packages/compiler/src/frontend/type-mapper.ts +++ b/packages/compiler/src/frontend/type-mapper.ts @@ -5139,11 +5139,15 @@ function mapGenericIndexedAccess(type: ts.Type, ctx: TypeMapperCtx): IrType | nu const obj = type.getObjectType(); if (obj === undefined || !(obj.flags & ts.TypeFlags.TypeParameter)) return null; const bound = resolveTypeParam(obj); + const idx = type.getIndexType(); + if (idx === undefined) return null; + // `T[keyof T]` over a T bound to an unknown-valued record view + // (`Record` maps to the checked-dynamic value, see + // mapRecordType): every member reads as unknown. + if (bound?.kind === "dyn" && idx.isIndexType() && idx.getTarget() === obj) return DYN; if (!bound || bound.kind !== "record") return null; const shape = shapes.get(bound.shapeId); if (!shape || shape.tuple) return null; - const idx = type.getIndexType(); - if (idx === undefined) return null; let covered: IrType[] | null = null; if (idx.isStringLiteralType()) { const f = shape.fields.find((x) => x.name === idx.value); @@ -5199,6 +5203,17 @@ function mapBoundKeyofNeverConditional(type: ts.Type, ctx: TypeMapperCtx): IrTyp const target = check.getTarget(); if (!target || !(target.flags & ts.TypeFlags.TypeParameter)) return null; const bound = resolveTypeParam(target); + // A T bound to the checked-dynamic value (`Record`, an + // unknown-valued record view) has no static key set to decide the + // branch, but both branches of the lib's `keyof T extends never ? + // unknown : T[keyof T]` read as unknown there: one answer either way. + if (bound?.kind === "dyn") { + const whenEmpty = type.getTrueType(); + const otherwise = type.getFalseType(); + const a = whenEmpty ? mapType(whenEmpty, ctx) : null; + const b = otherwise ? mapType(otherwise, ctx) : null; + return a && b && typeEquals(a, b) ? a : null; + } if (bound?.kind !== "record") return null; const shape = shapes.get(bound.shapeId); if (!shape || shape.tuple) return null; diff --git a/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6468-generic-unknown-record-entries.ts.json b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6468-generic-unknown-record-entries.ts.json new file mode 100644 index 0000000000..0b4118c70e --- /dev/null +++ b/packages/compiler/test/ts7/baselines/order-parity/tests/corpus/6468-generic-unknown-record-entries.ts.json @@ -0,0 +1,6 @@ +{ + "order": [ + "/tests/corpus/6468-generic-unknown-record-entries.ts" + ], + "diags": [] +} diff --git a/tests/corpus/6468-generic-unknown-record-entries.ts b/tests/corpus/6468-generic-unknown-record-entries.ts new file mode 100644 index 0000000000..f0e57756a2 --- /dev/null +++ b/tests/corpus/6468-generic-unknown-record-entries.ts @@ -0,0 +1,33 @@ +// Inside a generic body, `Object.entries(tags)` over `T extends +// Record` reads `[string, T[keyof T]]` elements. An +// instance whose T is the unknown-valued record view reads every member +// as unknown; a record instance reads the union of its member types. +function upper(text: string): string { + return text.toUpperCase(); +} + +function scrub(text: string): string { + return text.replace(/secret/g, "***"); +} + +function describe>(tags: T): string[] { + return Object.entries(tags).map( + ([key, value]) => `${key}=${typeof value === "string" ? upper(value) : String(value)}`, + ); +} + +function redact>(tags: T): T { + return Object.fromEntries( + Object.entries(tags).map(([key, value]) => [key, typeof value === "string" ? scrub(value) : value]), + ) as T; +} + +function flatten(value: unknown): Record { + return typeof value === "object" && value !== null ? (value as Record) : { value }; +} + +console.log(describe(flatten({ b: 1, a: "x", c: true }))); +console.log(describe(flatten(5))); +console.log(describe({ name: "n", size: 3 })); +const cleaned = redact(flatten({ token: "secret", count: 2 })); +console.log(cleaned, Object.keys(cleaned));