Fix Issue 19070 - Deprecate octal literal 00 through 07

[kubo39]

No description provided.

[dlang-bot]

Thanks for your pull request and interest in making D better, @kubo39! We are looking forward to reviewing it, and you should be hearing from a maintainer soon.
Please verify that your PR follows this checklist:

• My PR is fully covered with tests (you can see the annotated coverage diff directly on GitHub with CodeCov's browser extension
• My PR is as minimal as possible (smaller, focused PRs are easier to review than big ones)
• I have provided a detailed rationale explaining my changes
• New or modified functions have Ddoc comments (with Params: and Returns:)

Please see CONTRIBUTING.md for more information.

---

If you have addressed all reviews or aren't sure how to proceed, don't hesitate to ping us with a simple comment.

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	19070	trivial	Invalid octal literals 01 through 07 allowed

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub fetch digger
dub run digger -- build "master + dmd#8490"

[kubo39]

Octal literals widely used than I thought. It's better to allow only 01 through 07 as decimal literals, maybe.

[Geod24]

@kubo39 : D has a long history of not imposing unnecessary restrictions. This is a goof example of it IMO.
I don't think we are going to get rid of the error message, since it would break compatibility with C code, but disallowing 01 through 07 doesn't seem to add any value for the end user.

[kubo39]

I think so too, okay, close this.