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Don't reduce 'keyof M' for mapped types with non-distributive 'as' clauses (#41186)
* Don't reduce 'keyof M' for mapped types with non-distributive as clauses * Add regression test * Accept new baselines
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+223
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‎src/compiler/checker.ts

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -13475,6 +13475,19 @@ namespace ts {
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constraint;
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}
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// Ordinarily we reduce a keyof M where M is a mapped type { [P in K as N<P>]: X } to simply N<K>. This however presumes
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// that N distributes over union types, i.e. that N<A | B | C> is equivalent to N<A> | N<B> | N<C>. That presumption is
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// generally true, except when N is a non-distributive conditional type or an instantiable type with non-distributive
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// conditional type as a constituent. In those cases, we cannot reduce keyof M and need to preserve it as is.
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function isNonDistributiveNameType(type: Type | undefined): boolean {
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return !!(type && (
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type.flags & TypeFlags.Conditional && !(<ConditionalType>type).root.isDistributive ||
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type.flags & (TypeFlags.UnionOrIntersection | TypeFlags.TemplateLiteral) && some((<UnionOrIntersectionType | TemplateLiteralType>type).types, isNonDistributiveNameType) ||
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type.flags & (TypeFlags.Index | TypeFlags.StringMapping) && isNonDistributiveNameType((<IndexType | StringMappingType>type).type) ||
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type.flags & TypeFlags.IndexedAccess && isNonDistributiveNameType((<IndexedAccessType>type).indexType) ||
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type.flags & TypeFlags.Substitution && isNonDistributiveNameType((<SubstitutionType>type).substitute)));
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}
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function getLiteralTypeFromPropertyName(name: PropertyName) {
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if (isPrivateIdentifier(name)) {
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return neverType;
@@ -13522,7 +13535,7 @@ namespace ts {
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type = getReducedType(type);
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return type.flags & TypeFlags.Union ? getIntersectionType(map((<IntersectionType>type).types, t => getIndexType(t, stringsOnly, noIndexSignatures))) :
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type.flags & TypeFlags.Intersection ? getUnionType(map((<IntersectionType>type).types, t => getIndexType(t, stringsOnly, noIndexSignatures))) :
13525-
type.flags & TypeFlags.InstantiableNonPrimitive || isGenericTupleType(type) ? getIndexTypeForGenericType(<InstantiableType | UnionOrIntersectionType>type, stringsOnly) :
13538+
type.flags & TypeFlags.InstantiableNonPrimitive || isGenericTupleType(type) || isGenericMappedType(type) && isNonDistributiveNameType(getNameTypeFromMappedType(type)) ? getIndexTypeForGenericType(<InstantiableType | UnionOrIntersectionType>type, stringsOnly) :
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getObjectFlags(type) & ObjectFlags.Mapped ? getIndexTypeForMappedType(<MappedType>type, noIndexSignatures) :
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type === wildcardType ? wildcardType :
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type.flags & TypeFlags.Unknown ? neverType :

‎tests/baselines/reference/mappedTypeAsClauses.js

Lines changed: 54 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -57,6 +57,35 @@ const e1: T1 = {
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};
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type T2 = keyof T1;
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const e2: T2 = "foo";
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// Repro from #41133
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interface Car {
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name: string;
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seats: number;
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engine: Engine;
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wheels: Wheel[];
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}
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interface Engine {
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manufacturer: string;
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horsepower: number;
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}
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interface Wheel {
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type: "summer" | "winter";
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radius: number;
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}
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type Primitive = string | number | boolean;
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type OnlyPrimitives<T> = { [K in keyof T as T[K] extends Primitive ? K : never]: T[K] };
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let primitiveCar: OnlyPrimitives<Car>; // { name: string; seats: number; }
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let keys: keyof OnlyPrimitives<Car>; // "name" | "seats"
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type KeysOfPrimitives<T> = keyof OnlyPrimitives<T>;
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let carKeys: KeysOfPrimitives<Car>; // "name" | "seats"
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//// [mappedTypeAsClauses.js]
@@ -66,6 +95,9 @@ var e1 = {
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foo: "hello"
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};
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var e2 = "foo";
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var primitiveCar; // { name: string; seats: number; }
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var keys; // "name" | "seats"
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var carKeys; // "name" | "seats"
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//// [mappedTypeAsClauses.d.ts]
@@ -135,3 +167,25 @@ declare type T1 = PickByValueType<Example, string>;
135167
declare const e1: T1;
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declare type T2 = keyof T1;
137169
declare const e2: T2;
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interface Car {
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name: string;
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seats: number;
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engine: Engine;
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wheels: Wheel[];
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}
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interface Engine {
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manufacturer: string;
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horsepower: number;
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}
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interface Wheel {
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type: "summer" | "winter";
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radius: number;
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}
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declare type Primitive = string | number | boolean;
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declare type OnlyPrimitives<T> = {
186+
[K in keyof T as T[K] extends Primitive ? K : never]: T[K];
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};
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declare let primitiveCar: OnlyPrimitives<Car>;
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declare let keys: keyof OnlyPrimitives<Car>;
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declare type KeysOfPrimitives<T> = keyof OnlyPrimitives<T>;
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declare let carKeys: KeysOfPrimitives<Car>;

‎tests/baselines/reference/mappedTypeAsClauses.symbols

Lines changed: 76 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -188,3 +188,79 @@ const e2: T2 = "foo";
188188
>e2 : Symbol(e2, Decl(mappedTypeAsClauses.ts, 57, 5))
189189
>T2 : Symbol(T2, Decl(mappedTypeAsClauses.ts, 55, 2))
190190

191+
// Repro from #41133
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interface Car {
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>Car : Symbol(Car, Decl(mappedTypeAsClauses.ts, 57, 21))
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name: string;
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>name : Symbol(Car.name, Decl(mappedTypeAsClauses.ts, 61, 15))
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seats: number;
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>seats : Symbol(Car.seats, Decl(mappedTypeAsClauses.ts, 62, 17))
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engine: Engine;
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>engine : Symbol(Car.engine, Decl(mappedTypeAsClauses.ts, 63, 18))
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>Engine : Symbol(Engine, Decl(mappedTypeAsClauses.ts, 66, 1))
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wheels: Wheel[];
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>wheels : Symbol(Car.wheels, Decl(mappedTypeAsClauses.ts, 64, 19))
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>Wheel : Symbol(Wheel, Decl(mappedTypeAsClauses.ts, 71, 1))
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}
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interface Engine {
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>Engine : Symbol(Engine, Decl(mappedTypeAsClauses.ts, 66, 1))
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manufacturer: string;
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>manufacturer : Symbol(Engine.manufacturer, Decl(mappedTypeAsClauses.ts, 68, 18))
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horsepower: number;
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>horsepower : Symbol(Engine.horsepower, Decl(mappedTypeAsClauses.ts, 69, 25))
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}
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interface Wheel {
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>Wheel : Symbol(Wheel, Decl(mappedTypeAsClauses.ts, 71, 1))
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type: "summer" | "winter";
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>type : Symbol(Wheel.type, Decl(mappedTypeAsClauses.ts, 73, 17))
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radius: number;
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>radius : Symbol(Wheel.radius, Decl(mappedTypeAsClauses.ts, 74, 30))
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}
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type Primitive = string | number | boolean;
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>Primitive : Symbol(Primitive, Decl(mappedTypeAsClauses.ts, 76, 1))
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type OnlyPrimitives<T> = { [K in keyof T as T[K] extends Primitive ? K : never]: T[K] };
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>OnlyPrimitives : Symbol(OnlyPrimitives, Decl(mappedTypeAsClauses.ts, 78, 43))
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>T : Symbol(T, Decl(mappedTypeAsClauses.ts, 79, 20))
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>K : Symbol(K, Decl(mappedTypeAsClauses.ts, 79, 28))
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>T : Symbol(T, Decl(mappedTypeAsClauses.ts, 79, 20))
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>T : Symbol(T, Decl(mappedTypeAsClauses.ts, 79, 20))
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>K : Symbol(K, Decl(mappedTypeAsClauses.ts, 79, 28))
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>Primitive : Symbol(Primitive, Decl(mappedTypeAsClauses.ts, 76, 1))
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>K : Symbol(K, Decl(mappedTypeAsClauses.ts, 79, 28))
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>T : Symbol(T, Decl(mappedTypeAsClauses.ts, 79, 20))
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>K : Symbol(K, Decl(mappedTypeAsClauses.ts, 79, 28))
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let primitiveCar: OnlyPrimitives<Car>; // { name: string; seats: number; }
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>primitiveCar : Symbol(primitiveCar, Decl(mappedTypeAsClauses.ts, 81, 3))
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>OnlyPrimitives : Symbol(OnlyPrimitives, Decl(mappedTypeAsClauses.ts, 78, 43))
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>Car : Symbol(Car, Decl(mappedTypeAsClauses.ts, 57, 21))
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let keys: keyof OnlyPrimitives<Car>; // "name" | "seats"
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>keys : Symbol(keys, Decl(mappedTypeAsClauses.ts, 82, 3))
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>OnlyPrimitives : Symbol(OnlyPrimitives, Decl(mappedTypeAsClauses.ts, 78, 43))
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>Car : Symbol(Car, Decl(mappedTypeAsClauses.ts, 57, 21))
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type KeysOfPrimitives<T> = keyof OnlyPrimitives<T>;
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>KeysOfPrimitives : Symbol(KeysOfPrimitives, Decl(mappedTypeAsClauses.ts, 82, 36))
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>T : Symbol(T, Decl(mappedTypeAsClauses.ts, 84, 22))
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>OnlyPrimitives : Symbol(OnlyPrimitives, Decl(mappedTypeAsClauses.ts, 78, 43))
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>T : Symbol(T, Decl(mappedTypeAsClauses.ts, 84, 22))
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let carKeys: KeysOfPrimitives<Car>; // "name" | "seats"
263+
>carKeys : Symbol(carKeys, Decl(mappedTypeAsClauses.ts, 86, 3))
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>KeysOfPrimitives : Symbol(KeysOfPrimitives, Decl(mappedTypeAsClauses.ts, 82, 36))
265+
>Car : Symbol(Car, Decl(mappedTypeAsClauses.ts, 57, 21))
266+

‎tests/baselines/reference/mappedTypeAsClauses.types

Lines changed: 50 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -120,3 +120,53 @@ const e2: T2 = "foo";
120120
>e2 : "foo"
121121
>"foo" : "foo"
122122

123+
// Repro from #41133
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125+
interface Car {
126+
name: string;
127+
>name : string
128+
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seats: number;
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>seats : number
131+
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engine: Engine;
133+
>engine : Engine
134+
135+
wheels: Wheel[];
136+
>wheels : Wheel[]
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}
138+
139+
interface Engine {
140+
manufacturer: string;
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>manufacturer : string
142+
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horsepower: number;
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>horsepower : number
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}
146+
147+
interface Wheel {
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type: "summer" | "winter";
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>type : "summer" | "winter"
150+
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radius: number;
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>radius : number
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}
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type Primitive = string | number | boolean;
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>Primitive : Primitive
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type OnlyPrimitives<T> = { [K in keyof T as T[K] extends Primitive ? K : never]: T[K] };
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>OnlyPrimitives : OnlyPrimitives<T>
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let primitiveCar: OnlyPrimitives<Car>; // { name: string; seats: number; }
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>primitiveCar : OnlyPrimitives<Car>
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let keys: keyof OnlyPrimitives<Car>; // "name" | "seats"
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>keys : "name" | "seats"
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type KeysOfPrimitives<T> = keyof OnlyPrimitives<T>;
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>KeysOfPrimitives : keyof OnlyPrimitives<T>
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let carKeys: KeysOfPrimitives<Car>; // "name" | "seats"
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>carKeys : "name" | "seats"
172+

‎tests/cases/conformance/types/mapped/mappedTypeAsClauses.ts

Lines changed: 29 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -59,3 +59,32 @@ const e1: T1 = {
5959
};
6060
type T2 = keyof T1;
6161
const e2: T2 = "foo";
62+
63+
// Repro from #41133
64+
65+
interface Car {
66+
name: string;
67+
seats: number;
68+
engine: Engine;
69+
wheels: Wheel[];
70+
}
71+
72+
interface Engine {
73+
manufacturer: string;
74+
horsepower: number;
75+
}
76+
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interface Wheel {
78+
type: "summer" | "winter";
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radius: number;
80+
}
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82+
type Primitive = string | number | boolean;
83+
type OnlyPrimitives<T> = { [K in keyof T as T[K] extends Primitive ? K : never]: T[K] };
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85+
let primitiveCar: OnlyPrimitives<Car>; // { name: string; seats: number; }
86+
let keys: keyof OnlyPrimitives<Car>; // "name" | "seats"
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type KeysOfPrimitives<T> = keyof OnlyPrimitives<T>;
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let carKeys: KeysOfPrimitives<Car>; // "name" | "seats"

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