Re: What is the case against a struct post-blit default constructor?

[Era Scarecrow]

On Friday, 12 October 2012 at 08:20:42 UTC, Jonathan M Davis 
wrote:

Really, I think that it's a bad design decision to require that 
the invariant be called before opAssign. It does _not_ play 
nice with some of D's other features, and the result is likely 
to be that invariants get used less, meaning that code is more 
likely to be buggy.

 You make a good argument, but you can also override opAssign for 
things that are not it's type exact type. So...

 struct S {
   float x;

   ref S opAssign(int y) {
     x = y;
     return this;
   }
 }

 S s;
 int i;
 s = i; //opAssign, correct?


 In cases like this opAssign would need an invariant before and 
after the call. But if you were just replacing the whole object 
you wouldn't.

 I'll say a @novariant is the better answer, and automatically 
used on the default copy/opAssign/postblitz (before the call, but 
still needed after).