https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87824
--- Comment #19 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
On another look, (In reply to Iain Buclaw from comment #15)
> Still to do are:
>
> - runnable/cppa.d: (Remove struct __c_{u}long detection and tests)
> - runnable/eh.d: (Have -fno-reorder-blocks-and-partitions default for D)
> - runnable/nulltype.d (Set TYPE_TRANSPARENT_AGGR for D associative arrays)
>
> I'm still unsure about setting TYPE_TRANSPARENT_AGGR, it seems like its more
> masking something else on x86. Though as I've said, associative arrays are
> just a `struct{void*}` and treated as if it were a pointer anyway.
On another look, the D language implementation is treating `typeof(null)
function()` as being covariant with `int[int] function()`.
The former is a function that returns `void*`, the latter returns
`struct{void*}`.
There is no difference on x86_64, but on others the difference is subtle.
---
ret_typeof_null:
mov eax, 0
ret
ret_aa_null:
mov eax, DWORD PTR 4[esp]
mov DWORD PTR [eax], 0
ret 4
---
I'm going to send a change upstream that these types should not be covariant,
rather than changing the ABI of associative arrays by setting
TYPE_TRANSPARENT_AGGR.
