• olivier (18/18) Dec 02 2010 Hi,
• Adam Burton (8/32) Dec 02 2010 I don't believe the failing code uses opAssign. I believe that is
• Don (5/38) Dec 02 2010 My guess is that it's doing:
• olivier (4/5) Dec 03 2010 Yes, opAssign() is called. I can easily see that by adding a writefln()

olivier <h h.invalid> writes:

Hi,

This program, compiled with dmd 1.065 under Linux, crashes:

void main() {
	Num a = 1;
}

struct Num {
	int[] d;

	Num opAssign( int v ) {
		d.length = 1;
		d[0] = v;
		return *this;
	}
}

It looks like d is not initialized before opAssign() is called.
It doesn't crash if I replace "Num a = 1" with:
Num a;
a = 1;

Is this normal behaviour?

Adam Burton <adz21c gmail.com> writes:

olivier wrote:

 Hi,
 
 This program, compiled with dmd 1.065 under Linux, crashes:
 
 void main() {
 Num a = 1;
 }
 
 struct Num {
 int[] d;
 
 Num opAssign( int v ) {
 d.length = 1;
 d[0] = v;
 return *this;
 }
 }
 
 It looks like d is not initialized before opAssign() is called.
 It doesn't crash if I replace "Num a = 1" with:
 Num a;
 a = 1;
 
 Is this normal behaviour?

I don't believe the failing code uses opAssign. I believe that is 
initialization. In D2 "Num a = 1;" would be initialization or call a 
constructor if appropriate and "Num a; a = 1;" would use opAssign. Based on 
http://www.digitalmars.com/d/1.0/struct.html I am thinking it does the same 
(minus the constructors). So I think this might be a bug with struct 
initialization in D1, I don't think you should be able to just assign 1 to 
it.

Don <nospam nospam.com> writes:

Adam Burton wrote:
 olivier wrote:
 
 Hi,

 This program, compiled with dmd 1.065 under Linux, crashes:

 void main() {
 Num a = 1;
 }

 struct Num {
 int[] d;

 Num opAssign( int v ) {
 d.length = 1;
 d[0] = v;
 return *this;
 }
 }

 It looks like d is not initialized before opAssign() is called.
 It doesn't crash if I replace "Num a = 1" with:
 Num a;
 a = 1;

 Is this normal behaviour?

 I don't believe the failing code uses opAssign. I believe that is 
 initialization. In D2 "Num a = 1;" would be initialization or call a 
 constructor if appropriate and "Num a; a = 1;" would use opAssign. Based on 
 http://www.digitalmars.com/d/1.0/struct.html I am thinking it does the same 
 (minus the constructors). So I think this might be a bug with struct 
 initialization in D1, I don't think you should be able to just assign 1 to 
 it.

My guess is that it's doing:
a.d[] = 1;
and since d.length==0, that's a no-op.
It shouldn't compile.

olivier <h h.invalid> writes:

On Thu, 02 Dec 2010 17:32:41 +0000, Adam Burton wrote:

 I don't believe the failing code uses opAssign.

Yes, opAssign() is called. I can easily see that by adding a writefln() 
in it.
I guess I should file a bug report...