"declare global" prevents accessing parent scope (no-undef)

[JamesHenry]

This issue was initially reported here: eslint/typescript-eslint-parser#579

---

What version of TypeScript are you using?
3.1.3

What version of typescript-eslint-parser are you using?
21.0.2

What code were you trying to parse?

import React from 'react';

declare global {
  interface Global {
    __r: typeof React;
  }
}

// To complement `global.__r = React;`

What did you expect to happen?
No lint errors

What happened?

6:18 error 'React' is not defined no-undef

typescript-eslint-parser/analyze-scope.js:Referencer.visitGlobalAugmentation seems to replace the current scope with the global one, which makes accessing React in the above example
incorrectly say it's not defined.

@mysticatea (via #540): what case does visitGlobalAugmentation solve?

[ifiokjr]

@JamesHenry I'm running into the same error. It only happens a few times in my codebase so it's easy enough to ignore, but I'm wondering if there's a workaround or if there are any plans to update the rule.

[bradzacher]

Recommendation is to turn off the rule, as the typescript compiler itself should handle everything that the rule covers.

Otherwise - no plans right now. It involves adding scope analysis support, which is a huge piece of work none of the core maintainers have time to work on right now.

[bradzacher]

Merging into #1856