Fix Issue 20465 - Dynamic + static array declaration fail

[MoonlightSentinel]

Implements a cleaner solution for issue 10562 which tries to match the assigned expression against all dimensions of the target (instead of simply rewriting to keep type safety).

Rewrites the original test to orderly check all possible combinations.

[dlang-bot]

Thanks for your pull request and interest in making D better, @MoonlightSentinel! 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 coverage diff by visiting the details link of the codecov check)
• 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
✓	20465	regression	Dynamic + static array declaration fail

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 "stable + dmd#10698"

[Geod24]

Looks like you botched the rebase.

[Geod24]

Isn't it a bit too lax tho ?We always had the ability to assign a value to a slice, but never to assign a value to a multi dimensional array. Also, does it work with int[][] ?

[MoonlightSentinel]

Looks like you botched the rebase.

Fixed

Isn't it a bit too lax tho ?We always had the ability to assign a value to a slice, but never to assign a value to a multi dimensional array.

Maybe, but there was always a discrepancy between the initial construction and further usage of static arrays

int[2][3] x = 2; // Valid
x = 3;           // Invalid

Also, does it work with int[][] ?

This change applies to assignment/construction of an static array, do you have a specific example?

[Geod24]

This change applies to assignment/construction of an static array, do you have a specific example?

For starter:

int[3][] arr = new int[3][5];
arr = 42;

But you can extend it to int[][].

EDIT: Also, there's a reason why the discrepancy is possible. When you construct the array, you specify the type, while when you assign it, you don't.

[MoonlightSentinel]

This change applies to assignment/construction of an static array, do you have a specific example?

For starter:

int[3][] arr = new int[3][5];
arr = 42;

But you can extend it to int[][].

These are dynamic arrays and hence unaffected by this patch.
arr = 42 cannot be rewritten as an int[15] since the length is (usually) unknown at compile time (but maybe it would be possible to track it in this case)

[MoonlightSentinel]

Lets defer the discussion about the differences between construction and assignment to another PR as its not required to fix this regression (unless the test suite disagrees).

Got kinda carried away there ...

[MoonlightSentinel]

@Geod24 Restored the original restriction to non-assignments and adapted the test accordingly

[MoonlightSentinel]

Can this be merged or should we revert the faulty PR until we come to a conclusion? (Since the next release is due in a few days)