signed/unsigned mismatch #95

1>cppformat\format.cc(628): error C2220: warning treated as error - no 'object' file generated
1>          cppformat\format.cc(879) : see reference to function template instantiation 'void fmt::BasicWriter<char>::write_str<char>(const fmt::internal::Value::StringValue<char> &,const fmt::FormatSpec &)' being compiled
1>          cppformat\format.cc(879) : see reference to function template instantiation 'void fmt::BasicWriter<char>::write_str<char>(const fmt::internal::Value::StringValue<char> &,const fmt::FormatSpec &)' being compiled
1>          cppformat\format.cc(745) : while compiling class template member function 'void fmt::internal::PrintfFormatter<Char>::format(fmt::BasicWriter<Char> &,fmt::BasicStringRef<Char>,const fmt::ArgList &)'
1>          with
1>          [
1>              Char=char
1>          ]
1>          c:\users\sean\documents\projects\cppformat\format.h(2178) : see reference to function template instantiation 'void fmt::internal::PrintfFormatter<Char>::format(fmt::BasicWriter<Char> &,fmt::BasicStringRef<Char>,const fmt::ArgList &)' being compiled
1>          with
1>          [
1>              Char=char
1>          ]
1>          cppformat\format.cc(1120) : see reference to class template instantiation 'fmt::internal::PrintfFormatter<Char>' being compiled
1>          with
1>          [
1>              Char=char
1>          ]
1>cppformat\format.cc(628): warning C4018: '<' : signed/unsigned mismatch