Warning about multiple identical attributes in Svelte code

[oatymart]

In my Svelte component (code below) I have the following warning from this addon:

JSX elements cannot have multiple attributes with the same name. svelte-type-checker(17001)

However my code appears to be valid Svelte and works as expected.

<input type="text"
    on:focus|once={() => visited = true}
    on:focus={handleInput}
/>