no error when importing non-existent .svelte file

[DetachHead]

Describe the bug

when a .svelte file doesn't exist, no error is reported by svelte-check or by vscode

Reproduction

<script lang="ts">
    import Foo from 'Foo.svelte' //non-existent file
</script>

<main>
    <Foo />
</main>

Logs

> svelte-check --tsconfig ./tsconfig.json


====================================
Loading svelte-check in workspace: c:\Users\amogus\network-chungus
Getting Svelte diagnostics...

====================================
svelte-check found 0 errors, 0 warnings, and 0 hints

System Info

System:
    OS: Windows 10 10.0.19042
    CPU: (6) x64 Intel(R) Core(TM) i5-8600 CPU @ 3.10GHz
    Memory: 1.79 GB / 15.78 GB
  Binaries:
    Node: 16.9.1 - C:\Program Files\nodejs\node.EXE     
    npm: 7.24.1 - C:\Program Files\nodejs\npm.CMD       
  Browsers:
    Chrome: 99.0.4844.84
    Edge: Spartan (44.19041.1266.0), Chromium (99.0.1150.55)
    Internet Explorer: 11.0.19041.1566
  npmPackages:
    svelte: ^3.47.0 => 3.47.0

Severity

annoyance

[dummdidumm]

The problem is the

declare module "*.svelte";

definition inside Svelte core, which tells TS to treat every file ending with .svelte as if it exists. It can't be removed because people would get errors for all their Svelte file imports inside TypeScript files if they don't enable the TS plugin. I'm not sure how to make the diagnostic errors appear in another way. If there was a way to somehow ignore/exclude that ambient file definition (we know where inside the Svelte package it is located) that could be a way to do it - but it won't work using tsconfig.json's exclude setting because the ambient file is part of the Svelte file definition. We would have to remove it from the list of our files in the SnapshotManager maybe. We would also need to remove our similar module declaration inside svelte2tsx

[DetachHead]

It can't be removed because people would get errors for all their Svelte file imports inside TypeScript files if they don't enable the TS plugin.

is there a good reason to be using typescript without also using the plugin though? that just sounds to me like their project isn't set up correctly