Hello,

I got stuck with a weird array setting behaviour and I need help. Just have a look at the example.

OS: Win 8.1 Pro
DMD: v2.071.0
Build-cmd: dmd main.d -ofconsole-app.exe -debug -unittest -g -wi -m64

module dmain;
import std.stdio;

struct Vec {
	float a;
}

void main(string[] args) {
	Vec[] array = new Vec[4];

	writeln("before: ", array); //  prints [Vec(nan), Vec(nan), Vec(nan), Vec(nan)]
	
	array[] = Vec(24);

	writeln("after: ", array); // prints [Vec(0), Vec(0), Vec(0), Vec(0)]
}

Seems like slicing is broken in general. All the following variations produce different results but they are all wrong.
array[] = Vec(24);
array[0 .. 1] = Vec(24);
array[0 .. $] = Vec(24);

It works as expected if I do one of the following things:
1. Get rid of -m64. If I compile with -m32 flag then I cannot replicate the issue.

2. Changing the type of the Vec.a field from float to real, int, uint, long, ulong fixes the issue. Double still causes the issues.

3. Adding new fields to the Vec struct.

3.1. Vec {float a, b; } still does not work but the result is slightly different.
array[] = Vec(24, 5);
writeln("after: ", array); // [Vec(5, 0), Vec(5, 0), Vec(5, 0), Vec(5, 0)]

3.2. Vec { float a, b, c; } works fine.

4. Using index operator: array[0] = Vec(24) works fine

On 14/04/2016 2:49 AM, ref2401 wrote:
> Hello,
>
> I got stuck with a weird array setting behaviour and I need help. Just
> have a look at the example.
>
> OS: Win 8.1 Pro
> DMD: v2.071.0
> Build-cmd: dmd main.d -ofconsole-app.exe -debug -unittest -g -wi -m64
>
> module dmain;
> import std.stdio;
>
> struct Vec {
>      float a;
> }
>
> void main(string[] args) {
>      Vec[] array = new Vec[4];
>
>      writeln("before: ", array); //  prints [Vec(nan), Vec(nan),
> Vec(nan), Vec(nan)]
>
>      array[] = Vec(24);
>
>      writeln("after: ", array); // prints [Vec(0), Vec(0), Vec(0), Vec(0)]
> }
>
> Seems like slicing is broken in general. All the following variations
> produce different results but they are all wrong.
> array[] = Vec(24);
> array[0 .. 1] = Vec(24);
> array[0 .. $] = Vec(24);
>
> It works as expected if I do one of the following things:
> 1. Get rid of -m64. If I compile with -m32 flag then I cannot replicate
> the issue.
>
> 2. Changing the type of the Vec.a field from float to real, int, uint,
> long, ulong fixes the issue. Double still causes the issues.
>
> 3. Adding new fields to the Vec struct.
>
> 3.1. Vec {float a, b; } still does not work but the result is slightly
> different.
> array[] = Vec(24, 5);
> writeln("after: ", array); // [Vec(5, 0), Vec(5, 0), Vec(5, 0), Vec(5, 0)]
>
> 3.2. Vec { float a, b, c; } works fine.
>
> 4. Using index operator: array[0] = Vec(24) works fine

Verified that it is a codegen problem for Win64 and not *nix.
Please file a bug report.

On Wednesday, 13 April 2016 at 15:07:09 UTC, rikki cattermole wrote:

> Verified that it is a codegen problem for Win64 and not *nix.
> Please file a bug report.

https://issues.dlang.org/show_bug.cgi?id=15921
Done, Thanks