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Merge pull request #28965 from Microsoft/simplifyIndexedAccess

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Simplify indexed access types applied to mapped types
This commit is contained in:
Anders Hejlsberg 2018-12-11 17:56:03 -08:00 committed by GitHub
commit fecbdb68bd
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10 changed files with 120 additions and 36 deletions
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19
src/compiler/checker.ts
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@ -9686,26 +9686,15 @@ namespace ts {
// If the object type is a mapped type { [P in K]: E }, where K is generic, instantiate E using a mapper
// that substitutes the index type for P. For example, for an index access { [P in K]: Box<T[P]> }[X], we
// construct the type Box<T[X]>. We do not further simplify the result because mapped types can be recursive
// and we might never terminate.
// construct the type Box<T[X]>.
if (isGenericMappedType(objectType)) {
return type.simplified = substituteIndexedMappedType(objectType, type);
}
if (objectType.flags & TypeFlags.TypeParameter) {
const constraint = getConstraintOfTypeParameter(objectType as TypeParameter);
if (constraint && isGenericMappedType(constraint)) {
return type.simplified = substituteIndexedMappedType(constraint, type);
}
const mapper = createTypeMapper([getTypeParameterFromMappedType(objectType)], [type.indexType]);
const templateMapper = combineTypeMappers(objectType.mapper, mapper);
return type.simplified = mapType(instantiateType(getTemplateTypeFromMappedType(objectType), templateMapper), getSimplifiedType);
}
return type.simplified = type;
}
function substituteIndexedMappedType(objectType: MappedType, type: IndexedAccessType) {
const mapper = createTypeMapper([getTypeParameterFromMappedType(objectType)], [type.indexType]);
const templateMapper = combineTypeMappers(objectType.mapper, mapper);
return instantiateType(getTemplateTypeFromMappedType(objectType), templateMapper);
}
function getIndexedAccessType(objectType: Type, indexType: Type, accessNode?: ElementAccessExpression | IndexedAccessTypeNode | PropertyName, missingType = accessNode ? errorType : unknownType): Type {
if (objectType === wildcardType || indexType === wildcardType) {
return wildcardType;

8
tests/baselines/reference/keyofAndIndexedAccess.js
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@ -484,10 +484,10 @@ function onChangeGenericFunction<T>(handler: Handler<T & {preset: number}>) {
function updateIds<T extends Record<K, string>, K extends string>(
obj: T,
idFields: K[],
idMapping: { [oldId: string]: string }
idMapping: Partial<Record<T[K], T[K]>>
): Record<K, string> {
for (const idField of idFields) {
const newId = idMapping[obj[idField]];
const newId: T[K] | undefined = idMapping[obj[idField]];
if (newId) {
obj[idField] = newId;
}
@ -1312,9 +1312,7 @@ declare type Handler<T> = {
declare function onChangeGenericFunction<T>(handler: Handler<T & {
preset: number;
}>): void;
declare function updateIds<T extends Record<K, string>, K extends string>(obj: T, idFields: K[], idMapping: {
[oldId: string]: string;
}): Record<K, string>;
declare function updateIds<T extends Record<K, string>, K extends string>(obj: T, idFields: K[], idMapping: Partial<Record<T[K], T[K]>>): Record<K, string>;
declare function updateIds2<T extends {
[x: string]: string;
}, K extends keyof T>(obj: T, key: K, stringMap: {

13
tests/baselines/reference/keyofAndIndexedAccess.symbols
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@ -1767,9 +1767,14 @@ function updateIds<T extends Record<K, string>, K extends string>(
>idFields : Symbol(idFields, Decl(keyofAndIndexedAccess.ts, 483, 11))
>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 482, 47))
idMapping: { [oldId: string]: string }
idMapping: Partial<Record<T[K], T[K]>>
>idMapping : Symbol(idMapping, Decl(keyofAndIndexedAccess.ts, 484, 18))
>oldId : Symbol(oldId, Decl(keyofAndIndexedAccess.ts, 485, 18))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 482, 19))
>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 482, 47))
>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 482, 19))
>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 482, 47))
): Record<K, string> {
>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
@ -1779,8 +1784,10 @@ function updateIds<T extends Record<K, string>, K extends string>(
>idField : Symbol(idField, Decl(keyofAndIndexedAccess.ts, 487, 14))
>idFields : Symbol(idFields, Decl(keyofAndIndexedAccess.ts, 483, 11))
const newId = idMapping[obj[idField]];
const newId: T[K] | undefined = idMapping[obj[idField]];
>newId : Symbol(newId, Decl(keyofAndIndexedAccess.ts, 488, 13))
>T : Symbol(T, Decl(keyofAndIndexedAccess.ts, 482, 19))
>K : Symbol(K, Decl(keyofAndIndexedAccess.ts, 482, 47))
>idMapping : Symbol(idMapping, Decl(keyofAndIndexedAccess.ts, 484, 18))
>obj : Symbol(obj, Decl(keyofAndIndexedAccess.ts, 482, 66))
>idField : Symbol(idField, Decl(keyofAndIndexedAccess.ts, 487, 14))

21
tests/baselines/reference/keyofAndIndexedAccess.types
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@ -1731,7 +1731,7 @@ function onChangeGenericFunction<T>(handler: Handler<T & {preset: number}>) {
// Repro from #13285
function updateIds<T extends Record<K, string>, K extends string>(
>updateIds : <T extends Record<K, string>, K extends string>(obj: T, idFields: K[], idMapping: { [oldId: string]: string; }) => Record<K, string>
>updateIds : <T extends Record<K, string>, K extends string>(obj: T, idFields: K[], idMapping: Partial<Record<T[K], T[K]>>) => Record<K, string>
obj: T,
>obj : T
@ -1739,32 +1739,31 @@ function updateIds<T extends Record<K, string>, K extends string>(
idFields: K[],
>idFields : K[]
idMapping: { [oldId: string]: string }
>idMapping : { [oldId: string]: string; }
>oldId : string
idMapping: Partial<Record<T[K], T[K]>>
>idMapping : Partial<Record<T[K], T[K]>>
): Record<K, string> {
for (const idField of idFields) {
>idField : K
>idFields : K[]
const newId = idMapping[obj[idField]];
>newId : { [oldId: string]: string; }[T[K]]
>idMapping[obj[idField]] : { [oldId: string]: string; }[T[K]]
>idMapping : { [oldId: string]: string; }
const newId: T[K] | undefined = idMapping[obj[idField]];
>newId : T[K] | undefined
>idMapping[obj[idField]] : Partial<Record<T[K], T[K]>>[T[K]]
>idMapping : Partial<Record<T[K], T[K]>>
>obj[idField] : T[K]
>obj : T
>idField : K
if (newId) {
>newId : { [oldId: string]: string; }[T[K]]
>newId : T[K] | undefined
obj[idField] = newId;
>obj[idField] = newId : { [oldId: string]: string; }[T[K]]
>obj[idField] = newId : T[K]
>obj[idField] : T[K]
>obj : T
>idField : K
>newId : { [oldId: string]: string; }[T[K]]
>newId : T[K]
}
}
return obj;

10
tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt
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@ -321,4 +321,14 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(142,5): error
~~~~
!!! error TS2322: Type 'number[]' is not assignable to type 'T[K]'.
}
// Repro from #28839
function f30<T, K extends keyof T>() {
let x: Partial<Record<keyof T, string>>[K] = "hello";
}
function f31<T, K extends keyof T>() {
let x: Partial<Partial<Partial<Partial<Partial<Partial<Partial<Record<keyof T, string>>>>>>>>[K] = "hello";
}

17
tests/baselines/reference/keyofAndIndexedAccessErrors.js
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@ -142,6 +142,16 @@ function test1<T extends Record<string, any>, K extends keyof T>(t: T, k: K) {
t[k] = "hello"; // Error
t[k] = [10, 20]; // Error
}
// Repro from #28839
function f30<T, K extends keyof T>() {
let x: Partial<Record<keyof T, string>>[K] = "hello";
}
function f31<T, K extends keyof T>() {
let x: Partial<Partial<Partial<Partial<Partial<Partial<Partial<Record<keyof T, string>>>>>>>>[K] = "hello";
}
//// [keyofAndIndexedAccessErrors.js]
@ -215,3 +225,10 @@ function test1(t, k) {
t[k] = "hello"; // Error
t[k] = [10, 20]; // Error
}
// Repro from #28839
function f30() {
var x = "hello";
}
function f31() {
var x = "hello";
}

36
tests/baselines/reference/keyofAndIndexedAccessErrors.symbols
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@ -486,3 +486,39 @@ function test1<T extends Record<string, any>, K extends keyof T>(t: T, k: K) {
>k : Symbol(k, Decl(keyofAndIndexedAccessErrors.ts, 138, 70))
}
// Repro from #28839
function f30<T, K extends keyof T>() {
>f30 : Symbol(f30, Decl(keyofAndIndexedAccessErrors.ts, 142, 1))
>T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 146, 13))
>K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 146, 15))
>T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 146, 13))
let x: Partial<Record<keyof T, string>>[K] = "hello";
>x : Symbol(x, Decl(keyofAndIndexedAccessErrors.ts, 147, 7))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
>T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 146, 13))
>K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 146, 15))
}
function f31<T, K extends keyof T>() {
>f31 : Symbol(f31, Decl(keyofAndIndexedAccessErrors.ts, 148, 1))
>T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 150, 13))
>K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 150, 15))
>T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 150, 13))
let x: Partial<Partial<Partial<Partial<Partial<Partial<Partial<Record<keyof T, string>>>>>>>>[K] = "hello";
>x : Symbol(x, Decl(keyofAndIndexedAccessErrors.ts, 151, 7))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
>T : Symbol(T, Decl(keyofAndIndexedAccessErrors.ts, 150, 13))
>K : Symbol(K, Decl(keyofAndIndexedAccessErrors.ts, 150, 15))
}

18
tests/baselines/reference/keyofAndIndexedAccessErrors.types
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@ -465,3 +465,21 @@ function test1<T extends Record<string, any>, K extends keyof T>(t: T, k: K) {
>20 : 20
}
// Repro from #28839
function f30<T, K extends keyof T>() {
>f30 : <T, K extends keyof T>() => void
let x: Partial<Record<keyof T, string>>[K] = "hello";
>x : Partial<Record<keyof T, string>>[K]
>"hello" : "hello"
}
function f31<T, K extends keyof T>() {
>f31 : <T, K extends keyof T>() => void
let x: Partial<Partial<Partial<Partial<Partial<Partial<Partial<Record<keyof T, string>>>>>>>>[K] = "hello";
>x : Partial<Partial<Partial<Partial<Partial<Partial<Partial<Record<keyof T, string>>>>>>>>[K]
>"hello" : "hello"
}

4
tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
View File

@ -486,10 +486,10 @@ function onChangeGenericFunction<T>(handler: Handler<T & {preset: number}>) {
function updateIds<T extends Record<K, string>, K extends string>(
obj: T,
idFields: K[],
idMapping: { [oldId: string]: string }
idMapping: Partial<Record<T[K], T[K]>>
): Record<K, string> {
for (const idField of idFields) {
const newId = idMapping[obj[idField]];
const newId: T[K] | undefined = idMapping[obj[idField]];
if (newId) {
obj[idField] = newId;
}

10
tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts
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@ -141,3 +141,13 @@ function test1<T extends Record<string, any>, K extends keyof T>(t: T, k: K) {
t[k] = "hello"; // Error
t[k] = [10, 20]; // Error
}
// Repro from #28839
function f30<T, K extends keyof T>() {
let x: Partial<Record<keyof T, string>>[K] = "hello";
}
function f31<T, K extends keyof T>() {
let x: Partial<Partial<Partial<Partial<Partial<Partial<Partial<Record<keyof T, string>>>>>>>>[K] = "hello";
}