Dear all,
I try to use type erasure on the free function foo. However, VS 2015
failed to compile the following code, which is OK with GCC and CLang.
=========================================================
#include
#include
#include <typeindex>
std::type_index foo(int);
BOOST_TYPE_ERASURE_FREE((HasGetField), foo, 1)
using Type = boost::type_erasure::any<
HasGetField,
boost::type_erasure::_self const&
;
std::type_index foo(int) {
return typeid(int);
}
int main() {
Type x{ 1 };
foo(x);
return 0;
}
=========================================================
Source.cpp
C:\Program Files\Microsoft Visual Studio 14.0\VC\INCLUDE\xlocale(341):
warning C4530: C++ exception handler used, but unwind semantics are not
enabled. Specify /EHsc
Source.cpp(20): error C2668: 'boost::type_erasure::injectHasGetField>::foo': ambiguous call to
overloaded function
with
[
R=std::type_index,
Base=boost::type_erasure::any_base,boost::type_erasure::_self &&>>
]
Source.cpp(7): note: could be 'std::type_index
boost::type_erasure::injectHasGetField>::foo(eval_if_c<0,boost::type_erasure::detail::maybe_const_this_param,boost::type_erasure::as_param>::type)' [found using argument-dependent
lookup]
with
[
R=std::type_index,
Base=boost::type_erasure::any_base,boost::type_erasure::_self &&>>
]
Source.cpp(7): note: or 'std::type_index
boost::type_erasure::injectHasGetField>::foo(eval_if_c<0,boost::type_erasure::detail::maybe_const_this_param,boost::type_erasure::as_param>::type)' [found using argument-dependent
lookup]
with
[
R=std::type_index,
Base=boost::type_erasure::any_base,boost::type_erasure::_self &>>
]
Source.cpp(7): note: or 'std::type_index
boost::type_erasure::injectHasGetField>::foo(eval_if_c<0,boost::type_erasure::detail::maybe_const_this_param,boost::type_erasure::as_param>::type)' [found using argument-dependent
lookup]
with
[
R=std::type_index,
Base=boost::type_erasure::any_base,boost::type_erasure::_self>>
]
Source.cpp(7): note: or 'std::type_index
boost::type_erasure::injectHasGetField>::foo(eval_if_c<0,boost::type_erasure::detail::maybe_const_this_param,boost::type_erasure::as_param>::type)' [found using argument-dependent
lookup]
with
[
R=std::type_index,
Base=boost::type_erasure::any_base,const boost::type_erasure::_self &>>
]
Source.cpp(14): note: or 'std::type_index foo(int)'
Source.cpp(20): note: while trying to match the argument list '(Type)'
=========================================================
Moreover, I wonder whether the declaration is a must?
Thank you!
