Test case:
------------------------
static assert(!{
auto p = null;
return p !is null;
}());
------------------------
x.d(1): Error: static assert (!true) is false
------------------------
The problem is the strange statement 'cmp ^= -1' in https://github.com/D-Programming-Language/dmd/blob/master/src/interpret.c#L2338. When two pointers are both null, 'cmp' will be 1, and 'cmp ^ -1' is -2 which is also true.
(In reply to comment #0)
> Test case:
>
> ------------------------
> static assert(!{
> auto p = null;
> return p !is null;
> }());
> ------------------------
> x.d(1): Error: static assert (!true) is false
> ------------------------
>
> The problem is the strange statement 'cmp ^= -1' in
> https://github.com/D-Programming-Language/dmd/blob/master/src/interpret.c#L2338.
> When two pointers are both null, 'cmp' will be 1, and 'cmp ^ -1' is -2 which is
> also true.
IIRC that was copied from Equals() in constfold.c. The bug probably exists there as well.