swc/crates/swc_ecma_parser/tests/tsc/genericRestParameters3.ts

// @strict: true
// @declaration: true

declare let f1: (x: string, ...args: [string] | [number, boolean]) => void;
declare let f2: (x: string, y: string) => void;
declare let f3: (x: string, y: number, z: boolean) => void;
declare let f4: (...args: [string, string] | [string, number, boolean]) => void;

declare const t1: [string] | [number, boolean];
declare const t2: readonly [string] | [number, boolean];
declare const t3: [string] | readonly [number, boolean];
declare const t4: readonly [string] | readonly [number, boolean];

f1("foo", "abc");
f1("foo", 10, true);
f1("foo", ...t1);
f1("foo", ...t2);
f1("foo", ...t3);
f1("foo", ...t4);
f1("foo", 10);  // Error
f1("foo");  // Error

f2 = f1;
f3 = f1;
f4 = f1;
f1 = f2;  // Error
f1 = f3;  // Error
f1 = f4;

// Repro from #26110

interface CoolArray<E> extends Array<E> { 
    hello: number;
}

declare function foo<T extends any[]>(cb: (...args: T) => void): void;

foo<CoolArray<any>>();     // Error
foo<CoolArray<any>>(100);  // Error
foo<CoolArray<any>>(foo);  // Error

function bar<T extends any[]>(...args: T): T {
    return args;
}

let a = bar(10, 20);
let b = bar<CoolArray<number>>(10, 20);  // Error

declare function baz<T>(...args: CoolArray<T>): void;
declare const ca: CoolArray<number>;

baz();       // Error
baz(1);      // Error
baz(1, 2);   // Error
baz(...ca);  // Error

// Repro from #26491

declare function hmm<A extends [] | [number, string]>(...args: A): void;
hmm(); // okay, A = []
hmm(1, "s"); // okay, A = [1, "s"]
hmm("what"); // no error?  A = [] | [number, string] ?

// Repro from #35066

declare function foo2(...args: string[] | number[]): void;
let x2: ReadonlyArray<string> = ["hello"];
foo2(...x2);

// Repros from #47754

type RestParams = [y: string] | [y: number];

type Signature = (x: string, ...rest: RestParams) => void;

type MergedParams = Parameters<Signature>;  // [x: string, y: string] | [x: string, y: number]

declare let ff1: (...rest: [string, string] | [string, number]) => void;
declare let ff2: (x: string, ...rest: [string] | [number]) => void;

ff1 = ff2;
ff2 = ff1;

function ff3<A extends unknown[]>(s1: (...args: [x: string, ...rest: A | [number]]) => void, s2: (x: string, ...rest: A | [number]) => void) {
    s1 = s2;
    s2 = s1;
}