Defined function becomes undefined #17393
Description
Describe the bug
I've been migrating my app to Svelte 5 and found a declared function becomes undefined in some cases
I can avoid the issue by declaring it as a variable (const f = () => >..). Also this doesn't occur in the rune mode
Reproduction
https://svelte.dev/playground/32fe25bdf13a4cbe8bdf053d68dfe777?version=5.46.0
<script>
$: items = [];
function myFunction(value) {
}
console.log(typeof myFunction); // => undefined
</script>
{#each items.filter(myFunction) as item}
<input bind:value={item.value} />
{/each}
<style>
</style>Error: undefined is not a function
in <unknown>
in __wrapper.svelte
at Array.filter (<anonymous>)
at eval (playground:output:5734:31)
at untrack (playground:output:4402:11)
at eval (playground:output:5734:6)
at eval (playground:output:5066:21)
at update_reaction (playground:output:4010:17)
at execute_derived (playground:output:2244:13)
at update_derived (playground:output:2260:15)
at get (playground:output:4326:5)
at eval (playground:output:5100:32)
Logs
System Info
System:
OS: Linux 6.14 Ubuntu 24.04.2 LTS 24.04.2 LTS (Noble Numbat)
CPU: (4) x64 Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz
Memory: 9.94 GB / 15.42 GB
Container: Yes
Shell: 5.2.21 - /bin/bash
Binaries:
Node: 20.19.6 - /home/ubuntu/.nvm/versions/node/v20.19.6/bin/node
npm: 3.10.10 - /home/ubuntu/***/node_modules/.bin/npm
npmPackages:
svelte: ^5.46.0 => 5.46.0Severity
annoyance