Fix Issue 17684 - [REG 2.062] static alias this

[JinShil]

No description provided.

[dlang-bot]

Thanks for your pull request, @JinShil! We are looking forward to reviewing it, and you should be hearing from a maintainer soon.

Some tips to help speed things up:

• smaller, focused PRs are easier to review than big ones

• try not to mix up refactoring or style changes with bug fixes or feature enhancements

• provide helpful commit messages explaining the rationale behind each change

Bear in mind that large or tricky changes may require multiple rounds of review and revision.

Please see CONTRIBUTING.md for more information.

Bugzilla references

Auto-close	Bugzilla	Description
✓	17684	[REG 2.062] static alias this bug or incomplete implementation?

[PetarKirov]

It looks like the Jenkins failure was due to network issues, so I've restarted the test pipeline there.

[PetarKirov]

Missing final end of line. Consider setting up EditorConfig on your text editor, so that repo text editor settings - https://github.com/dlang/dmd/blob/master/.editorconfig - are automatically applied.

[JinShil]

Done. Thanks for the review.

[PetarKirov]

Looks good to me on a first glance, though expect more thorough review from the dmd devs.

[MartinNowak]

Weird language feature, but rather have it fully-working that half-working. Any specific use-case in mind?

[JinShil]

Any specific use-case in mind?

Yes, it's for my memory-mapped-io library where all registers and bitfields are modeled as static entities. I currently have to put a .value any time I use a register or bitfield, which is verbose, redundant, and monotonous especially given the number of times registers must be used in a typical embedded board support package (BSP). static alias this allows me to write int baudRate = UART.BR; instead of int baudRate = UART.BR.value;, making the code more pleasant to use and read.

You'd probably question the pattern I've used in that library, but it was chosen due to other limitations in the D language (e.g. modules-must-be-files and a few others). It would take a detailed blog post to explain it, so if you really want to know, contact me offline. Long story short...it wasn't arrived at thoughtlessly.