`@typescript-eslint/no-confusing-void-expression` conflicts with snippet/render in the same file

[KieranP]

Describe the bug

When a snippet is defined in the same Svelte component as the render call, the @typescript-eslint/no-confusing-void-expression ESLint rule throws the following error:

However, when a snippet is defined outside of the component, such as children, @render has no issues with it. For some reason, snippets defined in the component are typed differently than snippets defined outside and passed in via props.

The main difference I see is that the inline snippets type is ReturnType<import("svelte").Snippet> whereas children prop type is Snippet. Because the #snippet/@render is compiled and syntax specific, I have not found a way to disable the rule or work around it, e.g. this is not possible because the svelte compiler doesn't support type declarations in the #snippet call:

<script lang="ts">
  import type { Snippet } from 'svelte'
</script>

{#snippet heading(label: string): Snippet}
  <h1>{label}</h1>
{/snippet}

{@render heading('Welcome!')}

Reproduction

Install eslint and @typescript-eslint/eslint-plugin, enable the rule @typescript-eslint/no-confusing-void-expression, then use this snippet in a Svelte file:

{#snippet heading(label: string)}
  <h1>{label}</h1>
{/snippet}

{@render heading('Welcome!')}

Logs

System Info

System:
    OS: macOS 15.6.1
    CPU: (14) arm64 Apple M4 Pro
    Memory: 1.19 GB / 24.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.15.1 - ~/.asdf/installs/nodejs/22.15.1/bin/node
    Yarn: 4.9.3 - ~/.asdf/installs/nodejs/22.15.1/bin/yarn
    npm: 10.9.2 - ~/.asdf/plugins/nodejs/shims/npm
  Browsers:
    Brave Browser: 139.1.81.136
    Chrome: 139.0.7258.139
    Safari: 18.6
  npmPackages:
    svelte: ^5.38.3 => 5.38.3

Severity

annoyance