[Bug c++/21484] New: [g++] using typename doesn't work in case template : template inheritance

[Bug c++/21484] New: [g++] using typename doesn't work in case template : template inheritance

[smelkov at mph1 dot phys dot spbu dot ru]

Is it just me or what? 
 
===nested_defs.cpp=== 
template<typename T> 
struct A 
{ 
    typedef T value_type; 
}; 
 
 
template<class T> 
struct B : A<T> 
{ 
    using typename A<T>::value_type; 
    value_type  x; 
}; 
 
 
 
int main() 
{ 
    B<int> b; 
    b.x = 0; 
 
    return 0; 
} 
 
=== 
 
[kirr@tugrik tmp]$ g++ -g -c -Wall nested_defs.cpp  
nested_defs.cpp:12: error: 'value_type' does not name a type 
nested_defs.cpp:12: note: (perhaps 'typename A<T>::value_type' was intended) 
nested_defs.cpp: In function 'int main()': 
nested_defs.cpp:20: error: 'struct B<int>' has no member named 'x' 
 
[kirr@tugrik tmp]$ g++ -v 
Using built-in specs. 
Target: i686-pc-linux-gnu 
Configured with: ../gcc-4.0.0/configure --prefix=/usr/local/gcc-4.0.0--nocheck-native 
--with-gnu-as --with-gnu-ld --enable-threads=posix --with-arch=pentium3 
--with-tune=pentium4 --enable-__cxa_atexit --enable-languages=c,c++,java,f95 
--disable-checking --disable-nls 
Thread model: posix 
gcc version 4.0.0 
 
 
 
With Comeau C++ & Intel 8.0 C++ it is ok. 
 
 
--- 
By the way, if i want to access all members of A<T> inside B, without explicit using, typedef, 
etc, what can i do? 
 
damn, if B is not template it works 
 
=== 
template<typename T> 
struct A 
{ 
    typedef T value_type; 
}; 
 
 
struct B : A<int> 
{ 
    value_type  x; 
}; 
=== 
 
if A is not template it also works: 
 
=== 
struct A 
{ 
    typedef int value_type; 
}; 
 
 
template<typename T> 
struct B : A 
{ 
    value_type  x; 
}; 
=== 
 
only for template : template case it doesn't compile (g++, Comeau), although intel C++ 8.0 
works ok: 
 
=== 
template<typename T> 
struct A 
{ 
    typedef T value_type; 
}; 
 
 
template<typename T> 
struct B : A<T> 
{ 
    value_type  x; 
}; 
 
 
 
int main() 
{ 
    B<int> b; 
    b.x = 0; 
 
    return 0; 
} 
=== 
 
[kirr@tugrik tmp]$ /opt/intel_cc_80/bin/icc -c nested_defs.cpp  
[kirr@tugrik tmp]$ echo $? 
0

-- 
           Summary: [g++] using typename doesn't work in case template :
                    template inheritance
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: smelkov at mph1 dot phys dot spbu dot ru
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21484

[Bug c++/21484] [g++] using typename doesn't work in case template : template inheritance

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-10 16:35 -------
Your first example is valid code.

And the second.
And the third.

But the fourth is invalid code and ICC in strict mode also rejects it.

Confirmed, based on the first example, this comes down to using semantics which G++ does not 
always get right, there might be already a bug about this somewhere.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |rejects-valid
      Known to fail|                            |2.95.3 3.0.4 3.2.3 3.3.3
                   |                            |3.4.0 4.0.0 4.1.0
   Last reconfirmed|0000-00-00 00:00:00         |2005-05-10 16:35:14
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21484

[Bug c++/21484] [g++] using typename doesn't work in case template : template inheritance

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-10 17:42 -------
And I was right, there was a bug about this already, see PR 14258 which I am going to mark this bug as 
a dup of.

*** This bug has been marked as a duplicate of 14258 ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21484

[Bug c++/21484] [g++] using typename doesn't work in case template : template inheritance

[smelkov at mph1 dot phys dot spbu dot ru]

------- Additional Comments From smelkov at mph1 dot phys dot spbu dot ru  2005-05-11 05:09 -------
Excuse me. The following is unconditionally offtopic, but 
 
is there a way to use whole base namespace, say something like 
 
template<typename T> 
struct A { ... } 
 
template<typename T> 
struct B : A<T> 
{ 
    using A<T>::* ; 
 
   or  
   using A<T>::; 
}; 
 
/none of these works, but i think the idea is clear/ 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21484