[Bug c++/15980] New: parse error caused by default initializer for a template type function argument

[Bug c++/15980] New: parse error caused by default initializer for a template type function argument

[schoenebeck at software-engineering dot org]

We encountered that gcc fails to compile with a parse error if a template 
based function argument is assigned a default initializer in the function 
prototype. Here is a stand alone test case for the exact problem: 
 
 
#define BUG 
 
template<typename A, typename B> 
struct C {}; 
  
typedef C<int, int> C_int_int; 
  
int w_typedef(C<int,int> arg = C_int_int()) { 
        return 0; 
} 
  
int wo_typedef(C<int,int> arg = C<int,int>()) { 
        return 0; 
} 
  
struct S { 
        int w_typedef(C_int_int arg = C_int_int()) { 
                return 0; 
        } 
  
        #ifdef BUG 
        int wo_typedef(C<int, int> arg = C<int,int>()) { 
                return 0; 
        } 
        #endif 
}; 
  
int main(int argc, char* argv[]) { 
        w_typedef(); 
        wo_typedef(); 
  
        S s; 
        s.w_typedef(); 
        #ifdef BUG 
        s.wo_typedef(); 
        #endif 
  
        return 0; 
} 
 
 
It compiles fine when BUG is not defined though. This code failed with 
gcc 3.2.2, 3.3.3 and also with 3.4, using various distributions (e.g. Debian 
and RedHat).

-- 
           Summary: parse error caused by default initializer for a template
                    type function argument
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: schoenebeck at software-engineering dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15980

[Bug c++/15980] parse error caused by default initializer for a template type function argument

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-13 22:55 -------
This is a dup of bug 57, one of the oldest bugs in GCC which is suspended because there is a DR report 
about the problem and no can agrue of what the standard says.

A simple workaround is to do: 
        int wo_typedef(C<int, int> arg = (C<int,int>()))

note the parentheses around the default argument.

*** This bug has been marked as a duplicate of 57 ***

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15980

[Bug c++/15980] parse error caused by default initializer for a template type function argument

[schoenebeck at software-engineering dot org]

------- Additional Comments From schoenebeck at software-engineering dot org  2004-06-13 23:22 -------
Does it? Trying your proposed workaround gives me a "parse error before `;' 
token" (currently tested with gcc 3.2.2). 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15980

[Bug c++/15980] parse error caused by default initializer for a template type function argument

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-06-13 23:26 -------
oh, the workaround only works on 3.4.0 and above then.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15980