Thread overview
Is this a bug in __traits(hasMember..)?
Nov 08, 2011
Tobias Pankrath
Nov 08, 2011
Robert Clipsham
Nov 08, 2011
Tobias Pankrath
November 08, 2011
Please take a look at this code

--------------------
struct Bag(S...)
{
    alias S Types;
}

template Test(alias i, B)
{
    void fn() {
        foreach(t; B.Types)
        {
            switch(i) {
                case IndexOf!(t, B.Types):
                {
                    pragma(msg, __traits(allMembers, t));
                    pragma(msg, __traits(hasMember, t, "m"));
                    break;
                }
                default: {}
            }

        }
    }
}

struct A
{
    int m;
}


void main()
{

    int i;
    alias Test!(i, Bag!(A)).fn func;
}
-----------------

If I compile this, DMD will print
------------------
dmd test.d
tuple("m")
false
------------------

which is very confusing to me. Guess this is a bug?

Tobias
November 08, 2011
On 08/11/2011 20:09, Tobias Pankrath wrote:
> which is very confusing to me. Guess this is a bug?
>
> Tobias

Looks like a bug to me. This works:
----
struct Bag(S...)
{
    alias S Types;
}

template Test(/*alias i,*/ B)
{
    void fn() {
        foreach(t; B.Types)
        {
            pragma(msg, t.stringof);
            pragma(msg, __traits(allMembers, t));
            pragma(msg, __traits(hasMember, t, "m"));
        }
    }
}

struct A
{
    int m;
}
void main()
{
    /*int i;*/
    alias Test!(/*i,*/ Bag!(A)).fn func;
}
----

But if you uncomment everything I've commented then it fails. Definitely worth a bug report when you have time - http://d.puremagic.com/issues/

-- 
Robert
http://octarineparrot.com/
November 08, 2011
http://d.puremagic.com/issues/show_bug.cgi?id=6910