Fix: Error location mismatches after loader processing

[log101]

What kind of change does this PR introduce?

Fixes #12025

Updates error locations for modules processed by loaders. Previously, processing caused error locations to be mismatched with the original file. This PR solves this issue by updating error locations using source map information.

Did you add tests for your changes?

Yes, added a new stat test.

Does this PR introduce a breaking change?

This PR is not expected to introduce any breaking changes. It only effects error messages of modules with compilation errors.

What needs to be documented once your changes are merged?

This fix does not need to be documented. But it should be noted that loaders should also support source maps such as ts-loader for this fix to work.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: log101 / name: Furkan Erdem (9765c36, 7291ad6, 421a2af)

[webpack-bot]

For maintainers only:

• This needs to be documented (issue in webpack/webpack.js.org will be filed when merged)
• This needs to be backported to webpack 4 (issue will be created when merged)

[alexander-akait]

Why closed? 😞

[log101]

Why closed? 😞

I was planning to add updateErrorLocation function to webpack-sources repo and then open this again after it got merged. Should I keep it open?

[alexander-akait]

@log101 got it, but let's keep it open until we resolve