Svelte warning (unused export) displayed at wrong line since switching to typescript

[dominic-simplan]

Describe the bug
I have just switched my svelte project from js to typescript. Since then, a warning about an unused export is displayed at the wrong line.

I don't actually know if this is caused by the language-tools or if I should open this somewhere else?

Expected behavior
Warning should be displayed for the correct line.

Screenshots

First lines of the component:

<script lang="ts">
    import * as d3 from "d3";
    import * as formatDe from "d3-format/locale/de-DE.json";
    import { createEventDispatcher } from "svelte";

    export const NodeDetailsEvent = Object.freeze({
        LINK_EMPHASIZE: "linkEmphasize",
    });

    const dispatch = createEventDispatcher();

    export let width = "100%";
    export let height = "200px";
    export let responsive = false;
    export let selectedNode;

System (please complete the following information):

• OS: Windows 10
• IDE: VSCode 1.47.2
• Plugin/Package: "Svelte for VSCode"

"svelte": "^3.22.3",
"svelte-check": "^0.1.55",
"svelte-loader": "^2.13.6",
"svelte-preprocess": "^4.0.8",
"typescript": "^3.9.7",

[jasonlyu123]

Can you check if your tsconfig has sourcemap: false?

[dominic-simplan]

It doesn't, this is my tsconfig.json:

{
    "extends": "@tsconfig/svelte/tsconfig.json",
    "include": [
        "src/**/*",
        "src/node_modules"
    ],
    "exclude": [
        "node_modules/*",
        "dist/*"
    ],
    "compilerOptions": {
        "strict": false,
        "resolveJsonModule": true
    }
}

[dominic-simplan]

After adding "sourceMap": true to my tsconfig, it seems that the correct line is underlined, even though I wonder why it doesn't underline the whole line.

So is this the expected behaviour? If yes, maybe the sourceMap option could be added to the tsconfig in the blog post?

[jasonlyu123]

The problem is that if the preprocessed script doesn't have a sourcemap the warning would be targeting the transpiled javascript. @orta what do you think, should it default in the @tsconfig module?

[orta]

We should!

[dummdidumm]

"sourceMap": true now part of the base config.