[Boost-users] RE [date_time] error with g++-4.3.2

Subject: [Boost-users] RE [date_time] error with g++-4.3.2
From: frederic.bron_at_[hidden]
Date: 2009-01-07 11:15:46

boost-users-bounces_at_[hidden] a écrit sur 07/01/2009 13:37:18 :
>
> In file included from boost/date_time/local_time/tz_database.hpp:14,
>                  from boost/date_time/local_time/local_time.hpp:19,
>                  from boost/date_time.hpp:15,
> boost/date_time/tz_db_base.hpp:161: error: declaration of 'typedef
> class boost::date_time::dst_adjustment_offsets<typename
> time_zone_type::time_duration_type>
> boost::date_time::tz_db_base<time_zone_type, rule_type>::
> dst_adjustment_offsets'
> boost/date_time/time_zone_base.hpp:76: error: changes meaning of
> 'dst_adjustment_offsets' from 'class boost::date_time::
> dst_adjustment_offsets<typename time_zone_type::time_duration_type>'

Here is the code that gives an error:

namespace boost { namespace date_time {

template<class time_duration_type> class dst_adjustment_offsets { } ; // in date_time/time_zone_base.hpp

template<class time_zone_type, class rule_type> class tz_db_base { // in date_time/tz_db_base.hpp
      typedef dst_adjustment_offsets<time_duration_type> dst_adjustment_offsets;
} ;

}

I do not understand clearly if this should be allowed (i.e. to give a typedef the same name of a class template) but the standard (2003) says:

7.1.3 The typedef specifier [dcl.typedef]
§2:
In a given non-class scope, a typedef specifier can be used to redefine the name of any type declared in
that scope to refer to the type to which it already refers. [Example:
typedef struct s { /* ... */ } s;
typedef int I;
typedef int I;
typedef I I;
—end example]

but we are in a class scope

§3:
In a given scope, a typedef specifier shall not be used to redefine the name of any type declared in that
scope to refer to a different type. [Example:
class complex { /* ... */ };
typedef int complex; // error: redefinition
—end example] Similarly, in a given scope, a class or enumeration shall not be declared with the same
name as a typedef-name that is declared in that scope and refers to a type other than the class or enumeration
itself. [Example:
typedef int complex;
class complex { /* ... */ }; // error: redefinition
—end example]

are we in the same scope?

F. Bron

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