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AndaristAndarist
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Fixed an issue with apparent mapped type keys
1 parent a9460c8 commit 1a27fd9

8 files changed

Lines changed: 620 additions & 1 deletion

‎src/compiler/checker.ts‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -22486,7 +22486,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
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/*stringsOnly*/ false,
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t => void mappedKeys.push(instantiateType(nameType, appendTypeMapping(targetType.mapper, getTypeParameterFromMappedType(targetType), t))),
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);
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return getUnionType(mappedKeys);
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return mappedKeys.length ? getUnionType(mappedKeys) : stringNumberSymbolType;
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}
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function structuredTypeRelatedToWorker(source: Type, target: Type, reportErrors: boolean, intersectionState: IntersectionState, saveErrorInfo: ReturnType<typeof captureErrorCalculationState>): Ternary {

tests/baselines/reference/keyRemappingKeyofResult.js renamed to tests/baselines/reference/keyRemappingKeyofResult(strict=false).js

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -71,6 +71,19 @@ function g<T>() {
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x = "str";
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}
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// https://github.com/microsoft/TypeScript/issues/57827
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type StringKeys<T> = Extract<
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keyof {
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[P in keyof T as T[P] extends string ? P : never]: any;
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},
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string
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>;
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function test_57827<T>(z: StringKeys<T>) {
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const f: string = z;
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}
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export {};
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//// [keyRemappingKeyofResult.js]
@@ -98,4 +111,7 @@ function g() {
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x = sym;
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x = "str";
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}
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function test_57827(z) {
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const f = z;
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}
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export {};

tests/baselines/reference/keyRemappingKeyofResult.symbols renamed to tests/baselines/reference/keyRemappingKeyofResult(strict=false).symbols

Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -192,4 +192,35 @@ function g<T>() {
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>x : Symbol(x, Decl(keyRemappingKeyofResult.ts, 65, 7))
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}
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// https://github.com/microsoft/TypeScript/issues/57827
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type StringKeys<T> = Extract<
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>StringKeys : Symbol(StringKeys, Decl(keyRemappingKeyofResult.ts, 68, 1))
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>T : Symbol(T, Decl(keyRemappingKeyofResult.ts, 72, 16))
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>Extract : Symbol(Extract, Decl(lib.es5.d.ts, --, --))
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keyof {
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[P in keyof T as T[P] extends string ? P : never]: any;
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>P : Symbol(P, Decl(keyRemappingKeyofResult.ts, 74, 5))
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>T : Symbol(T, Decl(keyRemappingKeyofResult.ts, 72, 16))
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>T : Symbol(T, Decl(keyRemappingKeyofResult.ts, 72, 16))
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>P : Symbol(P, Decl(keyRemappingKeyofResult.ts, 74, 5))
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>P : Symbol(P, Decl(keyRemappingKeyofResult.ts, 74, 5))
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},
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string
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>;
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function test_57827<T>(z: StringKeys<T>) {
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>test_57827 : Symbol(test_57827, Decl(keyRemappingKeyofResult.ts, 77, 2))
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>T : Symbol(T, Decl(keyRemappingKeyofResult.ts, 79, 20))
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>z : Symbol(z, Decl(keyRemappingKeyofResult.ts, 79, 23))
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>StringKeys : Symbol(StringKeys, Decl(keyRemappingKeyofResult.ts, 68, 1))
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>T : Symbol(T, Decl(keyRemappingKeyofResult.ts, 79, 20))
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const f: string = z;
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>f : Symbol(f, Decl(keyRemappingKeyofResult.ts, 80, 7))
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>z : Symbol(z, Decl(keyRemappingKeyofResult.ts, 79, 23))
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}
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export {};

tests/baselines/reference/keyRemappingKeyofResult.types renamed to tests/baselines/reference/keyRemappingKeyofResult(strict=false).types

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -172,4 +172,24 @@ function g<T>() {
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>"str" : "str"
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}
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// https://github.com/microsoft/TypeScript/issues/57827
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type StringKeys<T> = Extract<
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>StringKeys : StringKeys<T>
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keyof {
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[P in keyof T as T[P] extends string ? P : never]: any;
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},
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string
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>;
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function test_57827<T>(z: StringKeys<T>) {
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>test_57827 : <T>(z: StringKeys<T>) => void
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>z : Extract<keyof { [P in keyof T as T[P] extends string ? P : never]: any; }, string>
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const f: string = z;
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>f : string
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>z : Extract<keyof { [P in keyof T as T[P] extends string ? P : never]: any; }, string>
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}
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export {};

‎tests/baselines/reference/keyRemappingKeyofResult(strict=true).js‎

Lines changed: 117 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,117 @@
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//// [tests/cases/compiler/keyRemappingKeyofResult.ts] ////
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//// [keyRemappingKeyofResult.ts]
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const sym = Symbol("")
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type Orig = { [k: string]: any, str: any, [sym]: any }
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type Okay = Exclude<keyof Orig, never>
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// type Okay = string | number | typeof sym
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type Remapped = { [K in keyof Orig as {} extends Record<K, any> ? never : K]: any }
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/* type Remapped = {
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str: any;
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[sym]: any;
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} */
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// no string index signature, right?
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type Oops = Exclude<keyof Remapped, never>
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declare let x: Oops;
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x = sym;
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x = "str";
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// type Oops = typeof sym <-- what happened to "str"?
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// equivalently, with an unresolved generic (no `exclude` shenanigans, since conditions won't execute):
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function f<T>() {
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type Orig = { [k: string]: any, str: any, [sym]: any } & T;
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type Okay = keyof Orig;
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let a: Okay;
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a = "str";
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a = sym;
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a = "whatever";
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// type Okay = string | number | typeof sym
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type Remapped = { [K in keyof Orig as {} extends Record<K, any> ? never : K]: any }
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/* type Remapped = {
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str: any;
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[sym]: any;
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} */
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// no string index signature, right?
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type Oops = keyof Remapped;
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let x: Oops;
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x = sym;
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x = "str";
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}
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// and another generic case with a _distributive_ mapping, to trigger a different branch in `getIndexType`
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function g<T>() {
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type Orig = { [k: string]: any, str: any, [sym]: any } & T;
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type Okay = keyof Orig;
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let a: Okay;
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a = "str";
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a = sym;
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a = "whatever";
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// type Okay = string | number | typeof sym
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type NonIndex<T extends PropertyKey> = {} extends Record<T, any> ? never : T;
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type DistributiveNonIndex<T extends PropertyKey> = T extends unknown ? NonIndex<T> : never;
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type Remapped = { [K in keyof Orig as DistributiveNonIndex<K>]: any }
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/* type Remapped = {
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str: any;
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[sym]: any;
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} */
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// no string index signature, right?
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type Oops = keyof Remapped;
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let x: Oops;
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x = sym;
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x = "str";
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}
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// https://github.com/microsoft/TypeScript/issues/57827
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type StringKeys<T> = Extract<
77+
keyof {
78+
[P in keyof T as T[P] extends string ? P : never]: any;
79+
},
80+
string
81+
>;
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83+
function test_57827<T>(z: StringKeys<T>) {
84+
const f: string = z;
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}
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export {};
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//// [keyRemappingKeyofResult.js]
90+
const sym = Symbol("");
91+
x = sym;
92+
x = "str";
93+
// type Oops = typeof sym <-- what happened to "str"?
94+
// equivalently, with an unresolved generic (no `exclude` shenanigans, since conditions won't execute):
95+
function f() {
96+
let a;
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a = "str";
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a = sym;
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a = "whatever";
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let x;
101+
x = sym;
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x = "str";
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}
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// and another generic case with a _distributive_ mapping, to trigger a different branch in `getIndexType`
105+
function g() {
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let a;
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a = "str";
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a = sym;
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a = "whatever";
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let x;
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x = sym;
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x = "str";
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}
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function test_57827(z) {
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const f = z;
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}
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export {};

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