Can't use `bind:checked` on radio input

[brandonpittman]

Describe the bug

I should be able to use bind:checked on radio inputs but I can't.

Reproduction

https://svelte.dev/playground/2517d8b9c0b94cf1bf850f2f96b71dc9?version=5.39.6

Logs

System Info

System:
    OS: macOS 15.7.1
    CPU: (10) arm64 Apple M1 Pro
    Memory: 113.45 MB / 16.00 GB
    Shell: 4.0.2 - /opt/homebrew/bin/fish
  Binaries:
    Node: 24.4.0 - ~/Library/pnpm/node
    Yarn: 1.22.19 - ~/Library/pnpm/yarn
    npm: 11.4.2 - ~/Library/pnpm/npm
    pnpm: 10.10.0 - ~/Library/pnpm/pnpm
    Deno: 2.3.1 - /opt/homebrew/bin/deno
  Browsers:
    Chrome: 140.0.7339.208
    Chrome Canary: 142.0.7441.0
    Safari: 26.0.1
  npmPackages:
    svelte: ^5.39.6 => 5.39.6

Severity

blocking all usage of svelte

[PatrickG]

Seems like the docs are incorrect.
And the error message could be better. In svelte 4 it was:
'checked' binding can only be used with <input type="checkbox"> — for <input type="radio">, use 'group' binding

[brandonpittman]

Okay. I expected check to work since it's a valid attribute for radio input. 🤷🏻‍♂️

[PatrickG]

Reopening. The docs need to be fixed. And maybe a better error message.

Okay. I expected check to work since it's a valid attribute for radio input. 🤷🏻‍♂️

I guess bind:checked does not work, because there is no event fired when a radio input gets unchecked by checking another radio input with the same name.