I guess one solution would be to use a temporary mortal instead of the targ

i just tried that. It doesn't work, because the mortals get freed on the return from the FETCH routine. I should have realised that would happen.

Ouch! I wonder how it can be fixed then?

Update: for completeness I should point out that, although it is indeed true that mortals get freed on return from the FETCH routine, that isn't the (only) reason this doesn't fix the problem. A correct (I hope!) diagnosis and patch can be found in the node below.

Update: This diagnosis is mistaken — see below.

Thanks for the pointer.

Update: In case it isn't clear, Rafael was talking about my fix when he said that it's fixed in bleadperl.

There is truth in what dave_the_m says, but the fact is that this behaviour is highly surprising, and can be fixed. It's better to make things behave sensibly than to spin elaborate explanations of why they don't. :-)