Incorrectly parses Svelte 5 snippets' returns

[lishaduck]

Before You File a Bug Report Please Confirm You Have Done The Following...

• I'm using eslint-plugin-svelte. (*.svelte file linting does not work with the parser alone. You should also use eslint-plugin-svelte with it.)
• I'm sure the problem is a parser problem. (If you are not sure, search for the issue in eslint-plugin-svelte repo and open the issue in eslint-plugin-svelte repo if there is no solution.
• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.

What version of ESLint are you using?

9.19.0

What version of eslint-plugin-svelte and svelte-eslint-parser are you using?

• svelte-eslint-parser@0.43.0
• eslint-plugin-svelte@3.0.0-next.16

What did you do?

Configuration

export default ts.config([
  ...ts.configs.recommendedTypeChecked,
  ...sveltePlugin.configs.recommended,
  {
    files: ["**/*.svelte"],
    languageOptions: {
      parserOptions: {
        extraFileExtensions: [".svelte"],
        parser: ts.parser,
        project: "./tsconfig.json",
      },
    },
    rules: {
      "@typescript-eslint/no-confusing-void-expression": "warn",
    },
  },
]);

{#snippet text(string: string)}
	{string}
{/snippet}

{@render text('Whoa')}

What did you expect to happen?

No errors.

What actually happened?

Placing a void expression inside another expression is forbidden. Move it to its own statement instead. eslint(@typescript-eslint/no-confusing-void-expression)

Link to GitHub Repo with Minimal Reproducible Example

https://github.com/lishaduck/sv-esl-prs-repro

Additional comments

sonarjs/no-use-of-empty-return-value also fails, so it's not just a types issue.

[baseballyama]

@ota-meshi

Reading the typescript-eslint source code, it appears that the following line always reports SvelteRenderTag. Since this issue cannot be resolved with parser tweaks, I believe the only option is to implement an extended rule in eslint-plugin-svelte. What do you think?

https://github.com/typescript-eslint/typescript-eslint/blob/662e62baca4ed8910d09b24db64ec3535e53863d/packages/eslint-plugin/src/rules/no-confusing-void-expression.ts#L360-L362

[ota-meshi]

Yeah, I think we need an extended rule, as you say.