Surprising behaviour of std.experimental.allocator

[svv1999]

On Thursday, 24 December 2020 at 16:12:31 UTC, Saurabh Das wrote:
> This causes a segfault when run with rdmd -gx:
[...]
On my machine its a "realloc(): invalid pointer".
 From what does the allocator know, that `p' is somehow an array?