Parsing fails on scriptless Vue files with typescript-eslint parser

When using an eslint config that specifies parserOptions.parser.ts, eslint errors while parsing files that do not have at least an empty <script lang="ts"></script>.

The eslint error is:

Error: Error while loading rule '@typescript-eslint/await-thenable': You have used a rule which requires parserServices to be generated. You must therefore provide a value for the "parserOptions.project" property for @typescript-eslint/parser.
Occurred while linting /src/error.vue
    at Object.getParserServices (/node_modules/@typescript-eslint/experimental-utils/dist/eslint-utils/getParserServices.js:16:15)
    at create (/node_modules/@typescript-eslint/eslint-plugin/dist/rules/await-thenable.js:41:37)
    at Object.create (/node_modules/@typescript-eslint/experimental-utils/dist/eslint-utils/RuleCreator.js:13:24)
    at createRuleListeners (/node_modules/eslint/lib/linter/linter.js:761:21)
    at /node_modules/eslint/lib/linter/linter.js:931:31
    at Array.forEach (<anonymous>)
    at runRules (/node_modules/eslint/lib/linter/linter.js:876:34)
    at Linter._verifyWithoutProcessors (/node_modules/eslint/lib/linter/linter.js:1175:31)
    at Linter._verifyWithConfigArray (/node_modules/eslint/lib/linter/linter.js:1273:21)
    at Linter.verify (/node_modules/eslint/lib/linter/linter.js:1228:25)

Config:

module.exports = {
    env: {
        es6: true,
        browser: true,
        node: true,
    },
    overrides: [
        {
            files: [
                '*.vue',
            ],
            plugins: [
                'vue', // With or without this, the error occurs
                '@typescript-eslint',
            ],
            parser: 'vue-eslint-parser',
            parserOptions: {
                parser: {
                    '<template>': 'espree',
                    ts: '@typescript-eslint/parser',
                },
                project: ['./tsconfig.json'],
                extraFileExtensions: ['.vue'],
            },
            rules: {
                '@typescript-eslint/await-thenable': 'error',
            },
        },
    ],
}

Reproduction: https://github.com/MatthiasKunnen/eslint-plugin-vue-ts-script.

[LinusBorg]

When you say “the same error”, are you referring to the error about the typescript-eslint rule?

That would be expected. A JS parser like spree can’t provide type informaiton to a type-aware rule. Using typescript-eslint - at the very least when using type-aware rules - will always require the typescript-eslint parser to be set.

[MatthiasKunnen]

A JS parser like spree can’t provide type informaiton to a type-aware rule.

I’m well aware. I was just remarking that a .vue file without <script> is currently parsed with a JS/TS parser while it would not need to be. While this is not a problem for me as I set js: '@typescript-eslint/parser', it might catch people off-guard as they could expect a file without script to not perform script parsing. Now I understand that due to ESLint limitations, selecting a JS/TS parser could be required. However, documenting the need for js: '@typescript-eslint/parser' would be beneficial for users that make the same assumption I did.