Re: [boost] Re: FC++ Formal review is now in progress (2/13-2/23)

From: boost_at_[hidden]
Date: 2004-02-13 18:30:14

At 21:53 13/02/2004, you wrote:

>Mat Marcus wrote:

<snip>

>(while compiling monad3.cpp)
>monad3.cpp:82: error: no type named `second_type' in `struct
>OutputMonad<std::string>'
>This is a template shadow parameter issue, related to the fact that
>OutputMonad<> defines an inner type called "M", but a template member 
>functions
>uses M as template parameter as well:
>
>struct A {
>   typedef int M;
>
>   template <class M>    //*
>   void foo(void)  {
>      M m;   // which M is this?
>   }
>};
>
>I know the C++ committe is discussing this issue at this moment. The argument
>would be that "M" names the typedef because it's "more stable" than the
>template parameter (which could get renamed in an out-of-class 
>definition). See
>also http://gcc.gnu.org/PR13967 for a detailed discussion. It's possible that
>GCC will emit a warning about this borderline case of shadowing, one day. This
>is worked around easily, by renaming the innest template parameter, in 
>line 107
>and 110, and all its subsequent uses.

I can't believe that???

So for

int i = 12;
{
         int i = 123;    //*
         std::cout << i;
}

should I expect an output of 12 because the other i is more stable?

Maybe I'm wrong, but it seems stupid to have one rule for one case, and a 
different rule for the effectively the same case.

The sensible opinion seems that the lines marked //* take precedence, 
albeit ideally with a warning.


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