On Monday, 11 April 2022 at 12:12:39 UTC, Salih Dincer wrote:
It worked for me in a different way.
1 is (about to be) alive!
2 is (already) dead.
2 is (already) dead.
2 is (already) dead.
2 is (already) dead.
2 is (already) dead.
Hello D!
1 is (already) dead.
Because I changed the code like this.
```d
struct S
{
. . .
string toString() { return ""; }
}
//S test(inout S s)/*
S test(S s)//*/
{
s.i = 2;
return s;
}
void main()
{
immutable s = S(1);
test(s).writeln;
"Hello".writefln!"%s D!";
}
```
If the inout is set, it does not allow compilation.
Because `S` does not contain any pointers or references, you are
allowed to create a mutable *copy* of an `S` from an `immutable`
source. That's what happens when you pass it to `test`.
The extra destructor calls come from the copies made by `test`
and `writeln`. If you add a copy constructor, you can see this
happening in the output:
```d
struct S {
/* ... */
this(ref inout typeof(this) other) inout {
this.i = other.i;
writeln(i, " was copied.");
}
}
```
```
1 is (about to be) alive!
1 was copied.
2 was copied.
2 is (already) dead.
2 was copied.
2 was copied.
2 was copied.
2 is (already) dead.
2 is (already) dead.
2 is (already) dead.
2 is (already) dead.
Hello D!
1 is (already) dead.
```
1 constructor call + 5 copies = 6 destructor calls.
