Compiler wraps else/catch statements into comments

[TheOtterlord]

Describe the bug

Writing a comment on the same line as a closing if statement, but the line before an else statement fails, as the else statement is wrapped into the comment.

This begins happening in Svelte 5.35.0

<script>
	if (true) {
		console.log('a')
	} // This breaks things
	else {
		console.log('b')
	}
</script>

<p>
	Hello
</p>

import 'svelte/internal/disclose-version';
import 'svelte/internal/flags/legacy';
import * as $ from 'svelte/internal/client';

var root = $.from_html(`<p>Hello</p>`);

export default function App($$anchor) {
	if (true) {
		console.log('a');
	} // This breaks things else {
		console.log('b');
	}

	var p = root();

	$.append($$anchor, p);
}

Reproduction

https://svelte.dev/playground/hello-world?version=5.35.0#H4sIAAAAAAAAA22PwQ6CQAxEf2XTC5AYuBNi4s0P8CYeFii6se5uaBUN4d_dGhMvHue1M9Mu4O0NoYY9EgUzh4kGk-PgBIcCNjA6Qob6uIC8ou4pSPzr2sVY8gNJlHWW8R_vgxf0kmKg4X5yUbatb8WNJpfpjoVZVLaS9jgQlhTOeWazQulqqsocLo5NN6G9spGL82fWERLjX2v3tba-qX59vomf2s-jOlKZrhN8CtR6yHpKyjqanR-gHm3KX99b7N01IAEAAA==

Logs

Failed to parse source for import analysis because the content contains invalid JS syntax. If you are using JSX, make sure to name the file with the .jsx or .tsx extension.
file: /home/otterlord/repos/.../src/components/CommentWidget.svelte:17:0

15: 
16:   $.append($$anchor, div);
17: }

System Info

System:
    OS: Linux 6.15 Arch Linux
    CPU: (8) x64 11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz
    Memory: 20.81 GB / 31.13 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 22.11.0 - /run/user/1000/fnm_multishells/31167_1751477101541/bin/node
    npm: 10.9.0 - /run/user/1000/fnm_multishells/31167_1751477101541/bin/npm
    pnpm: 10.12.3 - ~/.local/share/pnpm/pnpm
    bun: 1.1.38 - ~/.bun/bin/bun
  Browsers:
    Chromium: 137.0.7151.119
  npmPackages:
    svelte: 5.35.0 => 5.35.0

Severity

annoyance

[dummdidumm]

99% sure this is an upstream esrap issue

[dominikg]

likely caused by the change to esrap 2.0 in #16240 which slipped in to 5.35.0 without a changeset

[knd775]

Also running into this in khromov/svelte-render-scan

setTimeout(() => {
	this.#element.remove();
	activeHighlights.delete(this);
}, 250); // Match the CSS transition duration

becomes

setTimeout(
	() => {
		this.#element.remove();
		activeHighlights.delete(this);
	} // Match the CSS transition duration,
	250
)

leading to

Expected ',', got 'numeric literal (250, 250)'

[sp00m]

Very similar to an issue I'm facing with Svelecte if that helps: mskocik/svelecte#300

[dominikg]

single line comments in svelecte: https://github.com/search?q=repo%3Amskocik%2Fsvelecte+path%3A*.svelte+%2F%5C%2F%5C%2F%2F&type=code