Svelte: HTML comment causes misaligned sourcemap

[btamas]

In our project we should add license headers to source files, but when I did that in our first .svelte file, I experienced the generated sourcemap is incorrect and it ignores the comments.
It makes the debugging more difficult and the test coverage result is useless as well.

Svelte version: 3.14.0

Example .svelte source:

<!-- Some comment
and more
and more details -->
<script>
  const test = () => {
    console.log('test');
  }
</script>

When I want to debug test variable it points to the 2. line of the .svelte file.
This tool can help to visualize source map: http://evanw.github.io/source-map-visualization/

If I add the comment into the script tag, it works without any problem, but it looks stupid.

[tionkje]

Seems like anu svelte file where the script tag is not on the first line the sourcemap is off.
Like when adding a second script tag with context="module" the second script tag in the file is off by the amount of lines before that script tag.

[red8012]

Confirmed. Anything (even a blank line) goes before the script tag will cause the sourcemap line number to be incorrect.