* Move all getIndexedAccessType flags to AccessFlags enum * Preserve generics in contextual types for rest arguments * Add regression test
142 lines
2.7 KiB
TypeScript
142 lines
2.7 KiB
TypeScript
// @strict: true
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function f1<T extends string | undefined>(x: T, y: { a: T }, z: [T]): string {
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if (x) {
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x;
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x.length;
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return x;
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}
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if (y.a) {
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y.a.length;
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return y.a;
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}
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if (z[0]) {
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z[0].length;
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return z[0];
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}
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return "hello";
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}
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function f2<T>(x: Extract<T, string | undefined> | null): string {
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if (x) {
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x;
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x.length;
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return x;
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}
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return "hello";
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}
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interface Box<T> {
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item: T;
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}
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declare function isBox(x: any): x is Box<unknown>;
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declare function isUndefined(x: unknown): x is undefined;
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declare function unbox<T>(x: Box<T>): T;
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function g1<T extends Box<T> | undefined>(x: T) {
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if (isBox(x)) {
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unbox(x);
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}
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}
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function g2<T extends Box<T> | undefined>(x: T) {
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if (!isUndefined(x)) {
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unbox(x);
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}
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}
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function g3<T extends Box<T> | undefined>(x: T) {
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if (!isBox(x)) {
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unbox(x); // Error
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}
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}
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function g4<T extends Box<T> | undefined>(x: T) {
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if (isUndefined(x)) {
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unbox(x); // Error
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}
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}
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// Repro from #13995
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declare function takeA(val: 'A'): void;
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export function bounceAndTakeIfA<AB extends 'A' | 'B'>(value: AB): AB {
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if (value === 'A') {
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takeA(value);
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return value;
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}
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else {
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return value;
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}
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}
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// Repro from #13995
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type Common = { id: number };
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type AA = { tag: 'A', id: number };
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type BB = { tag: 'B', id: number, foo: number };
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type MyUnion = AA | BB;
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const fn = (value: MyUnion) => {
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value.foo; // Error
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if ('foo' in value) {
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value.foo;
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}
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if (value.tag === 'B') {
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value.foo;
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}
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};
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const fn2 = <T extends MyUnion>(value: T): MyUnion => {
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value.foo; // Error
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if ('foo' in value) {
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value.foo;
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}
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if (value.tag === 'B') {
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value.foo;
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}
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};
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// Repro from #13995
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type A1 = {
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testable: true
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doTest: () => void
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}
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type B1 = {
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testable: false
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};
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type Union = A1 | B1
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function notWorking<T extends Union>(object: T) {
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if (!object.testable) return;
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object.doTest();
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}
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// Repro from #42939
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interface A {
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a: number | null;
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};
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function get<K extends keyof A>(key: K, obj: A): number {
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const value = obj[key];
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if (value !== null) {
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return value;
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}
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return 0;
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};
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// Repro from #44093
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class EventEmitter<ET> {
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off<K extends keyof ET>(...args: [K, number] | [unknown, string]):void {}
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}
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function once<ET, T extends EventEmitter<ET>>(emittingObject: T, eventName: keyof ET): void {
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emittingObject.off(eventName, 0);
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emittingObject.off(eventName as typeof eventName, 0);
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}
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