rest parameter does not play well with generic array

[amir-arad]

TypeScript Version: 2.3.4

Code

// error, defined as ???
type Method<A extends Array<any>, R = void> = (...args: A) => R;

// this is still passed
const foo: Method<[number, string], string> = (a: string, b: number) => a + b;
// ^^^^^^ ^^^^^^ ^ ^

Expected behavior:
pass validation
Actual behavior:
Error:(1, 47) TS2370:A rest parameter must be of an array type.

[amir-arad]

my current replacement solution is:

 type Method<R = void> = (...args:any[]) => R;
 type Method0<R = void> = () => R;
 type Method1<T1, R = void> = (t1: T1) => R;
 type Method2<T1, T2, R = void> = (t1: T1, t2: T2) => R;
 type Method3<T1, T2, T3, R = void> = (t1: T1, t2: T2, t3: T3) => R;
 type Method4<T1, T2, T3, T4, R = void> = (t1: T1, t2: T2, t3: T3, t4: T4) => R;

[ikatyang]

It seems duplicate of #5331 and #5453?

Edit:

// error, defined as ???
type Method<A extends Array<any>, R = void> = (...args: A) => R;

// this is still passed
const foo: Method<[number, string], string> = (a: string, b: number) => a + b;
// ^^^^^^ ^^^^^^ ^ ^

[amir-arad]

thanks for the edit Ika (@ikatyang) . seems like a duplicate indeed.