Typescript: Arrow function: Block-scoped variable used before its declaration

[endel]

It's not possible to use arrow functions + inheritance anymore.

More info: https://basarat.gitbooks.io/typescript/content/docs/arrow-functions.html#tip-arrow-functions-and-inheritance

TypeScript Version: 2.2.1 / nightly (2.2.0-dev.201xxxxx)

Code

// A *self-contained* demonstration of the problem follows...
class Base {
    f = () => {
        console.log("one");
    }
}

class Child extends Base {
    super_f = this.f;
    f = () => {
        this.super_f();
        console.log("two");
    }
}

let c = new Child();
c.f();

Expected behavior:

Should output

one
two

Actual behavior:

index.ts(8,20): error TS2448: Block-scoped variable 'f' used before its declaration.

[RyanCavanaugh]

@basarat why did you write this down 😢 😭

[RyanCavanaugh]

Extra check we need is "You are allowed to access your own properties before they are initialized as long as your base class declares them"

[basarat]

why did you write this down 😢 😭

sowee :rose: but they asked how : https://github.com/basarat/typescript-book/issues/125#issue-163820339 :heart:

[broij]

This bug is also present in 2.2.2. I am also trying to use arrow functions inheritance and it fails with:
"Block-scoped variable '**' used before its declaration."

[rsaouti]

Yes,I use the version 2.2.2 and I have the same issue