<input type='number' /> value isn't parsed as a number when `type='number'` attribute is spread instead of being explicitly written

Describe the bug An input like <input type='number' /> will parse the value as a number, however if you were to spread the type='number' onto the input it will be parsed as a string instead

Logs N/A

To Reproduce https://svelte.dev/repl/1d4158ad6d4f4203a7fe2bfbfa4c05ec?version=3.23.2

Expected behavior Regardless of spreading the type='number' attribute or explicitly defining it, both should result in the value being parsed as a number.

Stacktraces N/A

Information about your Svelte project: REPL link uses v3.23.2

Severity There is a work around, and that’s to explicitly put the type='number' attribute. It’s just annoying that I can’t use the spread and results in a lot of duplication.

Additional context N/A

[Rich-Harris]

It’s technically impossible. It’s not just spread attributes, it’s any type attribute that could potentially change at runtime, as seen here:

The only potential solution (which isn’t something that’s currently on the roadmap, though the roadmap is always subject to change!) is to allow people to opt in to chunkier bundles in cases where type is dynamic. Not sure exactly what that would look like in terms of syntax etc; either way that should probably be a new issue, if someone were to raise it.

[Conduitry]

The bundle size would be increased. If the compiler can’t tell at compile time what the type of an <input> is (which it can’t when type is set by a spread) then it would need to include the relevant handling for type=text, type=number, type=radio, type=checkbox, etc.