Template + alias + basic type depends on another parameter = broken?

[Paul Backus]

On Wednesday, 22 February 2023 at 20:20:46 UTC, Dark Hole wrote:
> ```d
> template Foo(T, alias T[] Array) {
>     // ...
> }
> // ...
> Bar[] arr;
> Foo!(Bar, arr);
> ```
>
> This is valid D, but it doesn't work. It gives error "Error: 
> template instance `Foo!(Bar, arr)` does not match template 
> declaration `Foo(T, alias T[] Array)`".
>
> Of course, there is some ways to avoid this error (e.g. check 
> Array type in if), but I don't undestand why this code doesn't 
> compiles.

Pretty sure this is just a bug. There are a lot of edge-case bugs 
like this where template instantiation doesn't work the way it's 
supposed to.

I've submitted a bug report for this on issues.dlang.org: 
https://issues.dlang.org/show_bug.cgi?id=23733