Re: Error compiling program with nested template classes

Re: Error compiling program with nested template classes

[Dara Hazeghi]

Hello,

aside from the fact that line 3 should read:
static const int value = 0;

I don't see anything wrong. Intel's C++ accepts it as
valid (with the above change). Perhaps you've found a
bug. You can submit it through gcc's bugzilla.

Dara

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Error compiling program with nested template classes

[Dan May]

Hello,
   I have been having a problem compiling a program that has a templated 
structure inside of a templated structure.  here is some code that 
generates the compiler errors:

template<class T>
struct traits{
   static const int i = 0;
};

template<int i>
struct outer
{
   template<class T>
   struct inner{
     static void do_something(){
       //perform an action
     }
   };
};

template<class T>
void func(T t){
   outer< ::traits<T>::value>::inner<T>::do_something();
}

int main(int,char**){
   func('c');
}

there error messages are as follows:
temp.cc: In function `void func(T) [with T = char]':
temp.cc:23:   instantiated from here
temp.cc:19: error: type/value mismatch at argument 1 in template 
parameter list
    for `template<int i> struct outer'
temp.cc:19: error:   expected a constant of type `int', got `char'
temp.cc:19: error: type/value mismatch at argument 1 in template 
parameter list
    for `template<int i> template<class T> struct outer<i>::inner'
temp.cc:19: error:   expected a constant of type `int', got `char'
temp.cc:10: confused by earlier errors, bailing out

% gcc --version
gcc (GCC) 3.3.2
Copyright (C) 2003 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

I believe I am passing the correct template parameters.  If anyone could 
show me what I am doing wrong, or, if this is a bug, how to work around 
it I would be grateful.
Thanks,
-Dan May