Dynamic (@vite-ignore'd) import with // breaks JS transform

[gluck]

Describe the bug

Importing a dynamic URL with '//' in it will break the output JS:

// works
import(/*@vite-ignore*/ `https://unpkg.com/lodash`);

// works
import(/*@vite-ignore*/ `https://unpkg.com/${'lodash'}`);

// doesn't work (unexpected end of input)
import(/*@vite-ignore*/ `https://unpkg.com//${'lodash'}`);

This is cause by regex replacement here:

vite/packages/vite/src/node/plugins/importAnalysis.ts

Line 617 in 7d20580

.replace(/\/\*[\s\S]*?\*\/|([^\\:]|^)\/\/.*$/gm, '')

// raw === "/*@vite-ignore*/ `https://unpkg.com//${'lodash'}`"
          const url = rawUrl
            .replace(/\/\*[\s\S]*?\*\/|([^\\:]|^)\/\/.*$/gm, '')
            .trim()
// url === "`https://unpkg.co"

Reproduction

Minimal reproduction is here:
https://stackblitz.com/edit/vite-pgxelk?file=main.js

System Info

No plugin, both local & stackblitz webcontainer.
Vite@2.5.10

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/vue-next instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[Ontopic]

Ah, thanks, thought I was going mad.

[bluwy]

Still reproducible with Vite 2.9.0-beta.4, but it's not crashing the server now. Instead it gives a false warning that the vite-ignore comment is needed, even though already specified:

00:43:27 [vite] warning: 
/home/projects/vite-bbsbsc/main.js
2  |  
3  |  // works
4  |  import(/*@vite-ignore*/ `https://unpkg.com/${'lodash'}`);
   |                          ^
5  |  
6  |  // works
The above dynamic import cannot be analyzed by vite.
See https://github.com/rollup/plugins/tree/master/packages/dynamic-import-vars#limitations for supported dynamic import formats. If this is intended to be left as-is, you can use the /* @vite-ignore */ comment inside the import() call to suppress this warning.

  Plugin: vite:import-analysis
  File: /home/projects/vite-bbsbsc/main.js

[stackblitz]

Start a new pull request in StackBlitz Codeflow.

• vite-pgxelk (Open reproduction)