Flow annotations and no-undef + no-unused-vars

[pnevyk]

Hi,

I'd like to ask what is the status of handling no-undef and no-unused-vars of Flow type annotations directly in babel-eslint. If I understand it correctly, you started to use new eslint's scope API in lib/analyze-scope.js to implement a custom Referencer which should address these issues (or at least no-undef).

With babel-eslint@8.2.3, I identified these snippets as violating no-undef rule:

opaque type Foo = number;
type Foo = { foo<T>(x: T): T };
declare type Foo = number;
declare interface IFoo {}

And these are causing no-unused-vars error:

declare class Foo {}
declare module Foo {}
declare var Foo: number;
declare function foo(): void;

If babel-eslint implements these, corresponding rules in eslint-plugin-flowtype can be deprecated and removed eventually, as mentioned in this issue.

Is this a possibility or I am missing something?

[pascalduez]

I'm having a similar issue:

// @flow

import type { Foo } from './foo';

type Whatever<F = Foo> = {
  foo: F,
};

error  'Foo' is defined but never used  no-unused-vars

[kaicataldo]

Thank you for the issue. Now that @babel/eslint-parser has been released, we are making this repository read-only. If this is a change you would still like to advocate for, please reopen this in the babel/babel monorepo.