T.init, struct destructors and invariants - should they be called?

[Stanislav Blinov]

On Sunday, 18 November 2018 at 14:47:51 UTC, FeepingCreature 
wrote:
> On Sunday, 18 November 2018 at 14:38:09 UTC, Stanislav Blinov 
> wrote:
>> @safe unittest {
>>     Nullable!S a; // Look ma, no assert!
>> }
>
> a = S(new Object); // Look pa, assert!

...i.e. it should be:

// ...

     @property @trusted
     void value(T val) {
         if (!_hasValue) {
             import std.conv : emplace;
             auto addr = () @trusted { return &_payload(); } ();
             emplace(addr, val);
             _hasValue = true;
         } else
             _payload = val;
     }


// ...

since otherwise that calls opAssign. Unless you'd propose to not 
call invariants for that one too :*)