[boost] lexical_cast: even more warnings now

From: John Maddock (john_at_[hidden])
Date: 2006-08-05 11:46:29

We seem to have acquired even more intrusive warnings from lexical_cast now, 
for example a quickbook build yields:

/cygdrive/c/data/boost/develop/boost/boost/lexical_cast.hpp: In constructor 
`boo
st::detail::lexical_stream<Target, Source>::lexical_stream() [with Target = 
int,
 Source = std::basic_string<char, std::char_traits<char>, 
std::allocator<char> >
]':
/cygdrive/c/data/boost/develop/boost/boost/lexical_cast.hpp:230: 
instantiated
from `Target boost::detail::lexical_cast(typename 
boost::call_traits<T2>::value_
type) [with Target = int, Source = std::basic_string<char, 
std::char_traits<char
>, std::allocator<char> >]'
/cygdrive/c/data/boost/develop/boost/boost/lexical_cast.hpp:256: 
instantiated
from `Target boost::lexical_cast(const Source&) [with Target = int, Source = 
std
::basic_string<char, std::char_traits<char>, std::allocator<char> >]'
/cygdrive/c/data/boost/develop/boost/boost/program_options/detail/value_semantic
.hpp:83:   instantiated from `void 
boost::program_options::validate(boost::any&,
 const std::vector<std::basic_string<charT, std::char_traits<_CharT>, 
std::alloc
ator<_T2> >, std::allocator<std::basic_string<charT, 
std::char_traits<_CharT>, s
td::allocator<_T2> > > >&, T*, long int) [with T = int, charT = char]'
/cygdrive/c/data/boost/develop/boost/boost/program_options/detail/value_semantic
.hpp:151:   instantiated from `void boost::program_options::typed_value<T, 
charT
>::xparse(boost::any&, const std::vector<std::basic_string<charT, 
>std::char_trai
ts<_CharT>, std::allocator<_T2> >, std::allocator<std::basic_string<charT, 
std::
char_traits<_CharT>, std::allocator<_T2> > > >&) const [with T = int, charT 
= ch
ar]'
/cygdrive/c/data/boost/develop/boost/tools/quickbook/detail/quickbook.cpp:521:
 instantiated from here
/cygdrive/c/data/boost/develop/boost/boost/lexical_cast.hpp:150: warning: 
statem
ent has no effect

which is pretty unpleasant :-(

At least previously the warning only struct at level 4 in MSVC, now they 
seem to hit everything unfortunately.  Of course there may not be a solution 
that suites everyone!

John.