Is fullyQualifiedName supposed to work on templates? The
following fails:

struct MsgPack(T ...) {
}

struct TestPoint {
   float x, y;
}

alias TestPack = MsgPack!TestPoint;

void main() {
	
	import std.traits;
	import std.stdio;
	
	//writeln(fullyQualifiedName!TestPack);	          //Fails
	writeln(fullyQualifiedName!(MsgPack!TestPoint));  //Fails
}


with error:

/opt/compilers/dmd2/include/std/traits.d(340): Error: forward
reference of variable parentPrefix
/opt/compilers/dmd2/include/std/traits.d(501): Error: template
instance
std.traits.fullyQualifiedNameImplForSymbols!(MsgPack!(TestPoint))
error instantiating
/opt/compilers/dmd2/include/std/traits.d(292):
instantiated from here:
fullyQualifiedNameImplForTypes!(MsgPack!(TestPoint), false,
false, false, false)
/d112/f728.d(19):        instantiated from here:
fullyQualifiedName!(MsgPack!(TestPoint))
/opt/compilers/dmd2/include/std/traits.d(292): Error: template
instance
std.traits.fullyQualifiedNameImplForTypes!(MsgPack!(TestPoint),
false, false, false, false) error instantiating
/d112/f728.d(19):        instantiated from here:
fullyQualifiedName!(MsgPack!(TestPoint))
/d112/f728.d(19): Error: template instance
std.traits.fullyQualifiedName!(MsgPack!(TestPoint)) error
instantiating

https://d.puremagic.com/issues/show_bug.cgi?id=10502

On 01/24/2014 03:20 AM, "Øivind" wrote:
> Is fullyQualifiedName supposed to work on templates?

Yes.

> The following fails:

Compiler bug.

On Friday, 24 January 2014 at 09:38:24 UTC, Timon Gehr wrote:
>> The following fails:
>
> Compiler bug.

More like "Phobos bug that is very hard to fix because of compiler bug"

On Friday, 24 January 2014 at 09:40:32 UTC, Dicebot wrote:
> On Friday, 24 January 2014 at 09:38:24 UTC, Timon Gehr wrote:
>>> The following fails:
>>
>> Compiler bug.
>
> More like "Phobos bug that is very hard to fix because of compiler bug"

The bug hasn't been updated in half a year. Can we help with fixing it?
It's quite an issue if you want to copy a method with a mixin and you can't reliably stringify the return type.

On Friday, 24 January 2014 at 14:08:45 UTC, Martin Cejp wrote:
> It's quite an issue if you want to copy a method with a mixin and you can't reliably stringify the return type.

In general, you can't reliably stringify types for use in string mixins anyway. Just insert ReturnType!(…) or whatever you need directly into your mixin string.

Dvid

On Friday, 24 January 2014 at 14:31:01 UTC, David Nadlinger wrote:
> In general, you can't reliably stringify types for use in string mixins anyway.

May I ask why?
Anyway, thanks for the workaround.

On Friday, 24 January 2014 at 09:40:32 UTC, Dicebot wrote:
> On Friday, 24 January 2014 at 09:38:24 UTC, Timon Gehr wrote:
>>> The following fails:
>>
>> Compiler bug.
>
> More like "Phobos bug that is very hard to fix because of compiler bug"

Looking at the code, it does not seem like it pays any attention
to template parameters at all? I would expect that for a template
instantiation

A!(B, C)

it would resolve parents, etc. for A, B and C in turn..

How would I do that if I were to give it a go? E.g. for a
template instance A!(B, C), how do I use __traits or std.traits
to get the plain type A, and B and C so I can use e.g.
__traits(parent...) to figure out where they come from?

That is really all I need. For me C can be defined inside a
struct, so (A!(B, C)).stringof is not sufficient.. I would need a
result like e.g A!(B, X.C)

On 01/25/2014 02:06 AM, "Øivind" wrote:
> On Friday, 24 January 2014 at 09:40:32 UTC, Dicebot wrote:
>> On Friday, 24 January 2014 at 09:38:24 UTC, Timon Gehr wrote:
>>>> The following fails:
>>>
>>> Compiler bug.
>>
>> More like "Phobos bug that is very hard to fix because of compiler bug"
>
> Looking at the code, it does not seem like it pays any attention
> to template parameters at all? I would expect that for a template
> instantiation
>
> A!(B, C)
>
> it would resolve parents, etc. for A, B and C in turn..
>
> How would I do that if I were to give it a go? E.g. for a
> template instance A!(B, C), how do I use __traits or std.traits
> to get the plain type A, and B and C so I can use e.g.
> __traits(parent...) to figure out where they come from?
>
> That is really all I need. For me C can be defined inside a
> struct, so (A!(B, C)).stringof is not sufficient.. I would need a
> result like e.g A!(B, X.C)

alias Seq(T...)=T;

struct A(T...){}
struct B{}
struct C{}

alias T=A!(B,C);


static if(is(T==X!Y,alias X,Y...)){
    static assert(__traits(isSame, X, A));
    static assert(is(Y==Seq!(B,C)));
}

On Saturday, 25 January 2014 at 08:53:19 UTC, Timon Gehr wrote:
> alias Seq(T...)=T;
>
> struct A(T...){}
> struct B{}
> struct C{}
>
> alias T=A!(B,C);
>
>
> static if(is(T==X!Y,alias X,Y...)){
>     static assert(__traits(isSame, X, A));
>     static assert(is(Y==Seq!(B,C)));
> }

It won't work for templated function type though and probably some other cases I have forgotten by today. That was the problem locking fullyQualifiedName update as such functionality in Phobos is suppose to be generic.

That said, probably adding simple special case for aggregate types is worth it as it seems most common thing to encounter.