[Bug c++/36982] New: Unfolding of template function (in namesspace) using overloads (in same namespace) requires forward declarations

["lfn dot privat at mail dot dk" <gcc-bugzilla at gcc dot gnu dot org>]

// The following self-contained code (see below, I dont know how to 
// attach files to this report) produces the bug (see embedded comments).
// 
// The command compiler command line and output is as this:
//
//   g++ -c -O2 -I . -DSTATIC_BUILD -Wall x.cpp
//   x.cpp: In function bool ReadSpace::Read(const char*, 
//   std::vector<T, // std::allocator<_Tp1> >&) [with T = MyType]:
//   x.cpp:58: instantiated from here
//   x.cpp:34: error: invalid initialization of reference of type 
//             int& from expression of type MyType
//   x.cpp:27: error: in passing argument 2 of 
//             bool ReadSpace::Read(const char*, int&)
//
// Source code (x.cpp) ...
//

#include <vector>

/* <- Uncoment this block for GCC 4.3.1 workaround

//----------------------------------------------------------------------------
// Forward declarations needed by new GCC 4.3.1 compiler ...
//
// - Not needed by GCC 4.0.2 and previous versions !
// - Not needed by (Windows) MSC 8.0 (VS 2005) and previous versions !
//
// Note furthermore that IF everything is kept in the GLOBAL namespace,
// there is NO error - this, to me, indicates a GCC 4.3.1 compiler bug.
//
// LFN, 2008-07-31
//----------------------------------------------------------------------------

struct MyType;
namespace ReadSpace
{
  static inline bool Read( const char* Str, MyType& v );
};

*/

namespace ReadSpace
{
  static inline bool Read( const char* Str, int& v )
    { v = 0; return true; }

  template< class T >
  static inline bool Read( const char* Str, std::vector< T >& v )
  {
    T Help;
    if ( !Read( Str, Help ) )
      return false;
    v.push_back( Help );
    return true;
  }
}

struct MyType
{
  int i;
};

namespace ReadSpace // Extend the namespace ...
{
  static inline bool Read( const char* Str, MyType& v )
    { return Read( Str, v.i ); }
}

using namespace ReadSpace;

int main()
{
  std::vector< MyType > v;
  const char* Str = "25";
  return Read( Str, v ) ? 0 : 1;
}


-- 
           Summary: Unfolding of template function (in namesspace) using
                    overloads (in same namespace) requires forward
                    declarations
           Product: gcc
           Version: 4.3.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: lfn dot privat at mail dot dk
 GCC build triplet: Configured with: ../configure --prefix=/usr --with-
                    local-prefix=
  GCC host triplet: gcc version 4.3.1 20080507 (prerelease) [gcc-4_3-branch
                    revision
GCC target triplet: Target: i586-suse-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36982