template question

[Alexander Sieb]

Zoltan Nagy wrote:
> 
> Hi,
> 
> I tried to compile the small code below using the g++-3.2.1 but I got
> the following error message:
> 
> test.cc: In member function `void C<TTT>::ff() [with TTT = double]':
> test.cc:31:   instantiated from here
> test.cc:20: no matching function for call to `A<double>::f(B<const
> double&, double>&, double&)'
> 
> Is it a bug in the compiler or I do something wrong?
> 


Seems like T1 is ambiguous. 

  template<class T1, class T2>
  void f(const B<T1,T2>&, T1){}
                 ^^       ^^
                 ||       ||
 const double& from b.   double from function call
                      ||
                      \/
              What should T1 really be?

In b you define what becomes T1 as const double& while in the member function call
the second parameter is double. T1 cannot be both at the same time.

-- 
Regards,
	Alexander