Re: gcc 4.1.2 bug?

From:

Alberto Ganesh Barbati <AlbertoBarbati@libero.it>

Newsgroups:

comp.lang.c++.moderated

Date:

7 Nov 2006 19:00:37 -0500

Message-ID:

<Uq84h.33663$Fk1.67323@twister2.libero.it>

Greg Herlihy ha scritto:

Tarjan Denes wrote:

So the expectation is that is RD<T,v> when instantiated with
Attr::i_record_descriptor class template (defined below) will use a
specialization whenever T is the same type as Attr's own type
parameter.

The problem with this expectation, as I see it, is this: how can the
compiler tell what Attr's type parameter is when instantiating just the
Table record class template above? There is no way of recovering RD's
enclosing class template (or even to tell whether it has one) from the
template template parameter used to instantiate RD - and being able to
recover Attr's type parameter is necessary in order to match the
i_record_descriptor specialization. So without any way of testing
whether the specialization is a match, the compiler instantiates RD
with its general class template and not the provided specialization.

Nonsense. Consider the Attr ctor that references TableRecord:

     Attr()
     {
         TableRecord<A, 1, i_record_descriptor> tr;
     }

In this scope, A indicates the template parameter used to instantiate
the template Attr and i_record_descriptor clearly binds to
Attr<A>::i_record_descriptor. So what TableRecord gets is
Attr<A>::i_record_descriptor which provides all information needed to
match the partial specialization.

I'm prone to consider this a gcc bug.

Ganesh

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