No high order generics binding

[MOZGIII]

Bug Report

type GenericBinding<
    F extends <T1>(value: T1) => any,  // take a generic fn with T1 parameter
    T2,                                // also accept a T2 parameter
> = F<T2>;                             // bind the generic of F to T2

This does not work, although #47607 claims to have solved #40542 which is essentially this.

Test:

function myfn<T1>(value: T1) {};

const assert1a: typeof myfn extends (<T>(value: T) => void) ? true : false = true;
const assert1b: (<T>(value: T) => void) extends typeof myfn ? true : false = true;

type Test = GenericBinding<typeof myfn, string>; // bind `T1` at `myfn` to `string`, should get `(value: string) => void`

const assert2a: Test extends ((value: string) => void) ? true : false = true;
const assert2b: ((value: string) => void) extends Test ? true : false = true;

const assert2c: Test extends (<T>(value: T) => void) ? true : false = false;
const assert2d: (<T>(value: T) => void) extends Test ? true : false = false; // broken

🔎 Search Terms

High order generics.
#40542
#47607
#37181

🕗 Version & Regression Information

4.6 till 4.9.

⏯ Playground Link

Playground link with relevant code

💻 Code

See above.

🙁 Actual behavior

Compiler error Type 'F' is not generic.ts(2315).

🙂 Expected behavior

Actual evaluation of generics.

[andrewbranch]

F is a type, while #47607 and #40542 are about values.

[typescript-bot]

This issue has been marked 'Working as Intended' and has seen no recent activity. It has been automatically closed for house-keeping purposes.

[MOZGIII]

#40542 is clearly about types, #47607 only partially solves the issue described. If you follow what's going on at the code that is mentioned at #40542, the devs there were unable to meaningfully use the limited solution provided by #47607. I'd say that issue has to be reopened, as well as this one, which poses the same issue but in an explicitly broader sense.

This issue is marked with Working as intended, is it because it was submitted as a bug?