From the D Blog: Driving with D

[Iain Buclaw]

On Sunday, 6 June 2021 at 20:11:04 UTC, Max Samukha wrote:
> On Sunday, 6 June 2021 at 18:57:06 UTC, Max Samukha wrote:
>
>> 2) 'align' is mishandled
>
> GCC's bugzilla won't let me register.
>

You'd have to use a non-gmail account IIRC, not sure if there's 
any others that are in the "typically spam" blacklist.

> align(4)
> struct S {
>     ubyte[4] bytes;
> }
>
> static assert (S.alignof == 4); // fail, S.alignof == 1
>
> It's not specific to AVR. Worked around by placing 'align' 
> inside the struct.

That sounds a lot like this issue: 
https://issues.dlang.org/show_bug.cgi?id=17857

Can backport that for GCC-11.