On Tuesday, 25 October 2022 at 14:53:50 UTC, Adam D Ruppe wrote:
But just don't do this. Only basic values and immutable strings
are good to initialize this way. With the array or class
objects, you're liable to get some shared thing.
If you change this to be initialized in a constructor (which
will require an argument in D) or factory function, you'll get
far more consistent behavior as each instance will have its own
array.
I'd like to tune default ctor but structs can't have custom one.
Adding a ctor with parameter seems a hack to me - and compiler
still allows default construction even when default ctor is
disabled:
```d
struct A
{
int[] i;
}
struct B
{
A[] a;
@disable this();
this(bool)
{
A[] a = [A.init];
}
}
void main()
{
auto b1 = B.init;
b1.a[0].i ~= 1;
b1.a ~= A.init;
b1.a[0].i ~= 11;
b1.a[1].i ~= 12;
b1.writeln;
auto b2 = B.init;
b2.writeln;
}
```
This fails in run time, not compile time:
```
[email protected](19): index [0] is out
of bounds for array of length 0
----------------
??:? _d_arraybounds_indexp [0x55b558b8ec55]
./onlineapp.d:19 _Dmain [0x55b558b6bd5f]
```
As for why B() and B.init are different here... i don't know,
probably some subtly of the compiler's implementation.
Actually `auto b = B.init;` behaves the same way as `auto b =
B();` but they don't do the same as `B b;`
