implicit_cast in python/include/boost/python/opaque_pointer_converter.hpp should be boost:: qualified

[Paul Pluzhnikov <ppluzhnikov@…>]

The following test case fails to compile:

template <typename T>
inline T implicit_cast (void *) {
  // In reality there is an actual ::implicit_cast implementation in a header file
  return 0;  
}

#include <boost/python.hpp>

int main() {
  return 0;
}

The error is:

In file included from ./python/include/boost/python.hpp:49:0,
                 from /tmp/implicit_cast.cc:6:
./python/include/boost/python/opaque_pointer_converter.hpp: In static member function ‘static void* boost::python::opaque<Pointee>::extract(PyObject*)’:
./python/include/boost/python/opaque_pointer_converter.hpp:66:68: error: call of overloaded ‘implicit_cast(PyObject*&)’ is ambiguous
             ? static_cast<python_instance*>(implicit_cast<void*>(op))->x
                                                                    ^
./python/include/boost/python/opaque_pointer_converter.hpp:66:68: note: candidates are:
In file included from ./python/include/boost/python/converter/builtin_converters.hpp:11:0,
                 from ./python/include/boost/python/converter/arg_to_python.hpp:17,
                 from ./python/include/boost/python/call.hpp:15,
                 from ./python/include/boost/python/object_core.hpp:14,
                 from ./python/include/boost/python/args.hpp:25,
                 from ./python/include/boost/python.hpp:11,
                 from /tmp/implicit_cast.cc:6:
./conversion/include/boost/implicit_cast.hpp:25:10: note: T boost::implicit_cast(typename boost::detail::icast_identity<T>::type) [with T = void*; typename boost::detail::icast_identity<T>::type = void*]
 inline T implicit_cast (typename boost::detail::icast_identity<T>::type x) {
          ^
/tmp/implicit_cast.cc:2:10: note: T implicit_cast(void*) [with T = void*]
 inline T implicit_cast (void *) {
          ^

Proposed fix:

diff --git a/include/boost/python/opaque_pointer_converter.hpp b/include/boost/python/opaque_pointer_converter.hpp
index 10eb423..70ab1fe 100644
--- a/include/boost/python/opaque_pointer_converter.hpp
+++ b/include/boost/python/opaque_pointer_converter.hpp
@@ -63,7 +63,7 @@ private:
     static void* extract(PyObject* op)
     {
         return PyObject_TypeCheck(op, &type_object)
-            ? static_cast<python_instance*>(implicit_cast<void*>(op))->x
+            ? static_cast<python_instance*>(boost::implicit_cast<void*>(op))->x
             : 0
             ;
     }

[Paul Pluzhnikov <ppluzhnikov@…>]

Google ref: b/21321370