When I try to compile the code below, g++ reports "error: assuming cast to type
'bool (*)(evaluator&)' from overloaded function" on the line indicated. I have
isolated the comparison to the pointer to the template function "stop" as the
source of the problem. Is this the correct behavior?
#include <iostream>
struct evaluator { bool (*eval)(evaluator&); };
template <typename T>
bool stop(T &e) { return true; }
bool eval(evaluator &e) { return true; }
int main() {
typedef bool (*evalf)(evaluator&);
struct evaluator e = { stop<evaluator> };
// error: assuming cast to type 'bool (*)(evaluator&)' from
// overloaded function
std::cout << (e.eval == stop<evaluator>) << '\n';
// ok--eval is not templated
std::cout << (e.eval == eval) << '\n';
// ok--explicitly cast to correct type
std::cout << (e.eval == static_cast<evalf>(stop<evaluator>)) << '\n';
return 0;
}
I compiled this using the MinGW port of g++ 3.4.2 on W2kSP4. I unfortunately do
not have easy access to g++ 4.1.1, however Kai-Uwe Bux reports the same result
from that version via comp.lang.c++ (discussion archived at
http://groups.google.com/group/comp.lang.c++/browse_frm/thread/b25fee316ec891b6).
--
Summary: Comparison with Pointer to Template Function Requires
Explicit Cast
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: justin dot piper at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29187
