GCC Bugzilla Bug 20357

The following code produces the assembler message: 
"Error: symbol `_ZN1XIXadL_Z1fvEEEC1Ev' is already defined". 
If the declaration of f in main is omitted, everything is fine. 
 
typedef void (*Func) (); 
template <Func f> 
struct X { X () {} }; 
void f () {} 
X<f> x; 
int main () { 
  void f (); 
  X<f> x; 
}

Confirm as a bug.  It's still present in the mainline.

What is happening here is that multiple decls for f is getting in the way. 
Either we have to look at the 
DECL_UID or change the C++ front-end to only have one decl for f.