[@typescript-eslint/no-unused-vars] define interface in declare global namespace

[tjx666]

Repro

const { resolve } = require;
const OFF = 0;
const ERROR = 2;

module.exports = {
    env: {
        browser: true,
        es6: true,
        node: true,
        webextensions: true,
    },
    extends: [
        'airbnb',
        'airbnb/hooks',
        'plugin:eslint-comments/recommended',
        'plugin:import/typescript',
        'plugin:react/recommended',
        'plugin:@typescript-eslint/recommended',
        'plugin:unicorn/recommended',
        'plugin:promise/recommended',
        'prettier',
        'prettier/react',
        'prettier/@typescript-eslint',
    ],
    globals: {
        Atomics: 'readonly',
        SharedArrayBuffer: 'readonly',
    },
    parser: '@typescript-eslint/parser',
    parserOptions: {
        ecmaFeatures: {
            jsx: true,
        },
        ecmaVersion: 2020,
        sourceType: 'module',
    },
    plugins: ['@typescript-eslint', 'react', 'unicorn', 'promise'],
    settings: {
        'import/resolver': {
            node: {
                extensions: ['.ts', '.tsx', '.js', '.json'],
            },
            typescript: {
                directory: [resolve('./src/tsconfig.json'), resolve('./server/tsconfig.json')],
            },
        },
    },
    rules: {
        'eslint-comments/disable-enable-pair': [ERROR, { allowWholeFile: true }],

        'import/extensions': OFF,

        'react/jsx-indent': [ERROR, 4],
        'react/jsx-filename-extension': [ERROR, { extensions: ['.ts', '.tsx', '.json', '.js'] }],

        'unicorn/filename-case': [
            ERROR,
            {
                cases: {
                    camelCase: true,
                    pascalCase: true,
                },
            },
        ],
        'unicorn/no-process-exit': OFF,
        'unicorn/prevent-abbreviations': OFF,

        '@typescript-eslint/explicit-function-return-type': OFF,
        '@typescript-eslint/no-explicit-any': OFF,
        '@typescript-eslint/no-non-null-assertion': OFF,
        '@typescript-eslint/no-useless-constructor': ERROR,

        'func-names': OFF,
        'lines-between-class-members': OFF,
        'max-classes-per-file': OFF,
        'no-console': OFF,
        'no-empty': OFF,
        'no-underscore-dangle': OFF,
        'no-unused-expressions': OFF,
        'no-useless-constructor': OFF,
    },
    overrides: [
        {
            files: ['**/*.d.ts'],
            rules: {
                'import/no-duplicates': OFF,
            },
        },
        {
            files: ['server/**/*.ts'],
            rules: {
                'global-require': OFF,

                '@typescript-eslint/no-var-requires': OFF,

                'import/no-dynamic-require': OFF,
                'import/no-extraneous-dependencies': OFF,
            },
        },
    ],
};

import Path from 'path';
import puppeteer, { Browser } from 'puppeteer';

declare global {
    namespace NodeJS {
      interface Global {
        browser: Browser;
      }
    }
}

Expected Result

no error and warning.

Actual Result

'Browser' is defined but never used.

Additional Info

Did eslint throw an exception?

No.

Please run your lint again with the --debug flag, and dump the output below.
i.e. eslint --ext ".ts,.js" src --debug

Versions

package	version
@typescript-eslint/eslint-plugin	3.6.0
@typescript-eslint/parser	3.6.0
TypeScript	3.9.6
ESLint	7.4.0
node	12.18.2
npm	6.14.5
yarn	1.21.1

[bradzacher]

Please use the search before filing new issues
#2026, #2287, #1678, #1596, #1302, etc.

https://github.com/typescript-eslint/typescript-eslint/issues?q=is%3Aissue+%22no-unused-vars%22+global+

Also please read the pinned issues before filing new issues - #1856