• cal (14/14) Jun 23 2013 What is going on here?
• Anthony Goins (21/35) Jun 23 2013 import std.stdio, std.typecons;
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (22/42) Jun 23 2013 I think the OP is asking about the difference from when foo() is a
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (20/21) Jun 23 2013 Make that a Phobos bug. :)
• cal (3/26) Jun 23 2013 Actually I hadn't tried with free functions, but this test
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (4/5) Jun 24 2013 Thanks for filing:

"cal" <callumenator gmail.com> writes:

What is going on here?

import std.stdio, std.typecons;

struct S
{
     int x;
     Tuple!(S) foo() { return tuple(this); }
}

void main()
{
     S s;
     s.x = 8;
     writeln((s.foo()));     //output: Tuple!(S)(S(8))
     writeln((s.foo())[0]);  //output: S(0)
}

"Anthony Goins" <neontotem gmail.com> writes:

On Monday, 24 June 2013 at 01:22:12 UTC, cal wrote:
 What is going on here?

 import std.stdio, std.typecons;

 struct S
 {
     int x;
     Tuple!(S) foo() { return tuple(this); }
 }

 void main()
 {
     S s;
     s.x = 8;
     writeln((s.foo()));     //output: Tuple!(S)(S(8))
     writeln((s.foo())[0]);  //output: S(0)
 }

import std.stdio, std.typecons;

struct S
{
     int x;
     int y;
     int z;

     auto foo() { return tuple(this.tupleof); }
}

void main()
{
     S s;
     s.x = 8;
     s.y = 9;
     s.z = 10;
     writeln((s.foo()));     //output: Tuple!(int, int, int)(8, 9, 
10)

     writeln(s.foo()[2]);  //output: 10
}

Is this what you expected?
I would explain what's going on but I'd be wrong.

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 06/23/2013 09:40 PM, Anthony Goins wrote:

 On Monday, 24 June 2013 at 01:22:12 UTC, cal wrote:

     Tuple!(S) foo() { return tuple(this); }


 import std.stdio, std.typecons;

 struct S
 {
      int x;
      int y;
      int z;

      auto foo() { return tuple(this.tupleof); }
 }

 void main()
 {
      S s;
      s.x = 8;
      s.y = 9;
      s.z = 10;
      writeln((s.foo()));     //output: Tuple!(int, int, int)(8, 9, 10)

      writeln(s.foo()[2]);  //output: 10
 }

 Is this what you expected?

I think the OP is asking about the difference from when foo() is a 
non-member function:

import std.stdio, std.typecons;

struct S
{
     int x;
}

Tuple!(S) foo(S s)
{
     return tuple(s);
}

void main()
{
     S s;
     s.x = 8;
     writeln((s.foo()));     //output: Tuple!(S)(S(8))
     writeln((s.foo())[0]);  //output: S(8)
}

This time the output is S(8).

I think it is a compiler bug.

Ali

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 06/23/2013 10:07 PM, Ali Çehreli wrote:

 I think it is a compiler bug.

Make that a Phobos bug. :)

The following is a reduced program that exhibits the problem. The 
presence or absence of the unused member function makes a difference:

import std.typecons;

struct S
{
     int x;

     // Bizarre: Comment-out this function to pass the assert in main.
     Tuple!(S) unused()
     {
         return tuple(S(7));
     }
}

void main()
{
     auto s = S(8);

     assert(tuple(s).expand[0] == S(8));
}

Ali

"cal" <callumenator gmail.com> writes:

On Monday, 24 June 2013 at 05:31:29 UTC, Ali Çehreli wrote:
 On 06/23/2013 10:07 PM, Ali Çehreli wrote:

 I think it is a compiler bug.

 Make that a Phobos bug. :)

 The following is a reduced program that exhibits the problem. 
 The presence or absence of the unused member function makes a 
 difference:

 import std.typecons;

 struct S
 {
     int x;

     // Bizarre: Comment-out this function to pass the assert in 
 main.
     Tuple!(S) unused()
     {
         return tuple(S(7));
     }
 }

 void main()
 {
     auto s = S(8);

     assert(tuple(s).expand[0] == S(8));
 }

 Ali

Actually I hadn't tried with free functions, but this test 
captures my problem. I'll file it now. Thanks!

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 06/23/2013 11:11 PM, cal wrote:

 I'll file it now. Thanks!

Thanks for filing:

   http://d.puremagic.com/issues/show_bug.cgi?id=10458

Ali