std::initializer_list ambiguity in Visual Studio

Question

I'm trying to accept a std::initializer_list into a generic constructor like so:

template<typename T>
class Test{
  std::vector<T> V;

  Test(std::initializer_list<T>& list) : V(list){}

};

using

Test<int> test{ 1, 2, 3, 4 };

But I get the error:

error C2440: 'initializing' : cannot convert from 'initializer-list' to 'Test<int>' No constructor could take the source type, or constructor overload resolution was ambiguous

I'm just not sure what I'm doing wrong here.

Answer 1

Test(std::initializer_list<T>& list) : V(list){}

This takes the std::initializer_list by non-const reference, but you then try to bind a temporary to it, which is illegal

std::initializer_list is designed to be lightweight, so you can just pass it by value:

Test(std::initializer_list<T> list) : V(list){}
//                           ^ no &