https://issues.dlang.org/show_bug.cgi?id=16197

--- Comment #1 from Eyal <eyal@weka.io> ---
Specifically, the call to slice bit-blits the elements into the array but does not call postblit!

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https://issues.dlang.org/show_bug.cgi?id=16197

Steven Schveighoffer <schveiguy@yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[The D Bug Tracker]         |Postblit not being called
                   |                            |properly

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https://issues.dlang.org/show_bug.cgi?id=16197

--- Comment #2 from Eyal <eyal@weka.io> ---
Oops, this is an ldc bug, not a dmd bug.

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https://issues.dlang.org/show_bug.cgi?id=16197

David Nadlinger <code@klickverbot.at> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |code@klickverbot.at

--- Comment #3 from David Nadlinger <code@klickverbot.at> ---
DMD from Git master (v2.072.0-devel-20e1c81) seems to call too many postblits/ctors, though, when initialising the Ctr instances and then assigning the Elem literals:
---
construct Ctr {
POSTBLIT -1 (7FFF5C07F598)
POSTBLIT -1 (7FFF5C07F59C)
POSTBLIT -1 (7FFF5C07F5A0)
}
assign arr {
CTOR 1 (7FFF5C07F5B4)
CTOR 2 (7FFF5C07F5C0)
CTOR 3 (7FFF5C07F5C4)
}
slice rval -> arr {
POSTBLIT 1 (7FFF5C07F5D0)
POSTBLIT 2 (7FFF5C07F5D4)
POSTBLIT 3 (7FFF5C07F5D8)
}
DTOR 3 (7FFF5C07F5D8)
DTOR 2 (7FFF5C07F5D4)
DTOR 1 (7FFF5C07F5D0)
arr rval -> arr {
POSTBLIT 1 (7FFF5C07F520)
POSTBLIT 2 (7FFF5C07F524)
POSTBLIT 3 (7FFF5C07F528)
}
DTOR 3 (7FFF5C07F5F0)
DTOR 2 (7FFF5C07F5EC)
DTOR 1 (7FFF5C07F5E8)
DTOR 3 (7FFF5C07F5A0)
DTOR 2 (7FFF5C07F59C)
DTOR 1 (7FFF5C07F598)
---

Note that the CTOR-created instances (7FFF5C07F5B4 and so on) are never
destructed.

(The output is from a slightly modified test case that prints the struct address in parens:

---
import std.stdio:writeln;

struct Elem {
    int x = -1;
    this(int x) { this.x = x; writeln("CTOR ", x, " (", cast(void*)&this, ")");
}
    this(this) { writeln("POSTBLIT ", x, " (", cast(void*)&this, ")"); }
    ~this()    { if (x!=-1) writeln("DTOR "    , x, " (", cast(void*)&this,
")"); }
}

struct Ctr {
    Elem[3] arr;
    Elem[] slice() { return arr; }
    Elem[3] arrVal() { return arr; }
}

void main() {
    writeln("construct Ctr {");
    auto p = Ctr();
    writeln("}");
    writeln("assign arr {");
    p.arr = [Elem(1), Elem(2), Elem(3)];
    writeln("}");
    {
        writeln("slice rval -> arr {");
        Elem[3] _arr = p.slice;
        writeln("}");
    }
    {
        writeln("arr rval -> arr {");
        Elem[3] _arr = p.arrVal();
        writeln("}");
    }
}
---
)

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https://issues.dlang.org/show_bug.cgi?id=16197

David Nadlinger <code@klickverbot.at> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Postblit not being called   |Constructors/postblits and
                   |properly                    |destructors don't match up
                   |                            |for array initialisation

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https://issues.dlang.org/show_bug.cgi?id=16197

Steven Schveighoffer <schveiguy@yahoo.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |schveiguy@yahoo.com

--- Comment #4 from Steven Schveighoffer <schveiguy@yahoo.com> ---
(In reply to David Nadlinger from comment #3)
> Note that the CTOR-created instances (7FFF5C07F5B4 and so on) are never
> destructed.

I don't think this is really a sign of anything, since the compiler is free to move around instances of the struct.

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https://issues.dlang.org/show_bug.cgi?id=16197

--- Comment #5 from David Nadlinger <code@klickverbot.at> ---
(In reply to Steven Schveighoffer from comment #4)
> I don't think this is really a sign of anything, since the compiler is free to move around instances of the struct.

I'm not sure how to reconcile the number of ctor/postblit calls with the number of dtor calls, though.

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https://issues.dlang.org/show_bug.cgi?id=16197

--- Comment #6 from Steven Schveighoffer <schveiguy@yahoo.com> ---
I'm not saying there's no issue here, just that the fact that you are not matching the addresses of the structs together doesn't necessarily mean anything bad. The compiler could be running the ctor on some piece of memory, and then just moving into the right spot without calling postblit or dtor (seems wasteful, but certainly legal).

BTW, things can likely get a lot clearer if we reduce the array size to 1. No reason to triple the output!

BTW, the postblit for the -1 values seems incorrect...

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https://issues.dlang.org/show_bug.cgi?id=16197

ZombineDev <petar.p.kirov@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |petar.p.kirov@gmail.com

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https://issues.dlang.org/show_bug.cgi?id=16197

Max Samukha <maxsamukha@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |maxsamukha@gmail.com

--- Comment #7 from Max Samukha <maxsamukha@gmail.com> ---
(In reply to Steven Schveighoffer from comment #6)

> 
> BTW, the postblit for the -1 values seems incorrect...

Definitely incorrect (dmd):

struct Elem {
    int x = -1;
    this(this) { writeln("POSTBLIT ", x); }
    ~this()    { writeln("DTOR "    , x); }
}

struct Ctr {
    Elem[1] arr;
}

void main() {
    auto p = Ctr();
}

prints:

POSTBLIT DTOR


Should be either two destructors or no postblit. For "Elem arr" instead of "Elem[1] arr", only the destructor is correctly called once.

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