https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83264
Bug ID: 83264
Summary: std::initializer_list with a single element selects
the wrong overload
Product: gcc
Version: 7.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rustamabd at gmail dot com
Target Milestone: ---
Consider the following:
#include <iostream>
#include <initializer_list>
using namespace std;
template<typename T>
struct A {
A(int) {
cout << "A(int)\n";
}
A(std::initializer_list<T>) {
cout << "A(initializer_list)\n";
}
};
struct UdfInt {
UdfInt(int) {}
};
int main() {
A<UdfInt> obj({ 10 });
return 0;
}
GCC (any version) prints "A(initializer_list)". Other compilers (clang, MSVC)
print "A(int)".
According to [dcl.init.list]/3.9, a single-element braced-init-list should be
unwrapped which means the A(int) overload is the best viable alternative since
the other one needs a user-defined conversion.
