[Bug c++/23826] New: invalid use of constructor as a template

[Bug c++/23826] New: invalid use of constructor as a template

[harold at alum dot mit dot edu]

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The following code compiled in g++ 3.3.4, but does not compile in the latest 4.0.x
Seems like a regression testing oversight.
 
 
template <typename T, typename ID_TYPE=long>
class db_reference {
  private:
    T r;
  public:
    ID_TYPE &id;
    db_reference(ID_TYPE req_id=0);
    T &get();
    std::string print(int full_subtables=0, int show_ids=1, int no_refs=0) const;
    std::string print_xml(int full_subtables=1, int show_ids=0, int no_refs=1,
        const char *tag=0) const;
    void parse_xml(std::string &buf, const char *tag);
    void parse(const std::string &buf);
    void parse(const SQL_ROW &buf);
    operator T() const;
    T *operator ->();
    const T *operator ->() const;
    db_reference<T,ID_TYPE> &operator =(T &t);
    db_reference<T,ID_TYPE> &operator =(const db_reference<T,ID_TYPE> &t);
};
 
template <typename T, typename ID_TYPE>
db_reference<T,ID_TYPE>::db_reference<T,ID_TYPE>(ID_TYPE req_id) : id(*(ID_TYPE
*)(&(r.id))) {
  id=req_id;
}
 
The error is
  error: invalid use of constructor as a template
  note: use ‘db_reference<T, ID_TYPE>::db_reference’ instead of ‘db_reference<T,
ID_TYPE>::db_reference<T, ID_TYPE>’ to name the constructor in a qualified name

-- 
           Summary: invalid use of constructor as a template
           Product: gcc
           Version: 4.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: harold at alum dot mit dot edu
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: 4.0.x
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23826

[Bug c++/23826] invalid use of constructor as a template

[pinskia at gcc dot gnu dot org]

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------- Additional Comments From pinskia at gcc dot gnu dot org  2005-09-11 23:39 -------
(In reply to comment #0)
> The following code compiled in g++ 3.3.4, but does not compile in the latest 4.0.x
> Seems like a regression testing oversight.
Nope, see below.

> The error is
>   error: invalid use of constructor as a template
>   note: use ‘db_reference<T, ID_TYPE>::db_reference’ instead of ‘db_reference<T,
> ID_TYPE>::db_reference<T, ID_TYPE>’ to name the constructor in a qualified name

The error even says how to fix your code.  In fact the note part was added so people don't confuse
what the error message meant.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23826

[Bug c++/23826] invalid use of constructor as a template

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2005-09-11 23:46 -------
For the reporter: what the compiler is telling you is that your code is not 
valid ISO C++.  What it is not telling you is that G++ 3.3.4 did not really 
actually know what is valid C++ and what is not. 
 
In GCC 3.4 and later there is a new C++ parser that is ISO C++ conforming.  
Sadly for you, this means that while older G++ versions accepted your invalid 
C++, newer G++ releases do not, and you have to fix your code to make it work. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23826