Re: [boost] [tti] compiler error: shadows template param `class T`

Subject: Re: [boost] [tti] compiler error: shadows template param `class T`
From: Edward Diener (eldiener_at_[hidden])
Date: 2011-08-10 22:19:48

On 8/10/2011 9:37 PM, Lorenzo Caminiti wrote:
> Hello,
>
> The TTI library macros expand to code that uses naive template
> parameter names like "T", "F", "U", etc. The library implementation
> should be changed to use library reserved names to avoid clashing with
> user template parameter names. For example, the library use a name
> like boost_tti_aux_T (or even better BOOST_PP_CAT(boost_tti_aux_T_,
> __LINE__)) instead of T and state in the documentation that any name
> prefixed by boost_tti_aux (in any namespace) is reserved for the
> library implementation. The same should be done for any other
> implementation symbol defined by the TTI library.
>
> This is an issue if the macros are expanded for example within a class
> (which is and should be possible after changing them not to expand in
> the boost::tti namespace). For example, assuming
> BOOST_TTI_HAS_COMP_MEMBER_FUNCTION is fixed not to expand in
> boost::tti then the following:
>
> template<  typename T>
> struct myvector {
>      BOOST_TTI_HAS_COMP_MEMBER_FUNCTION_TRAIT(has_push_back, push_back)
> // expand to code using a template parameter naively named T
>      ...
> };
>
> Will generate a compiler error on GCC "error: shadows template param class T".

This is a good suggestion, which I will implement. Thanks for bringing 
it up.