c++ - Construct container with initializer list of iterators -

it's possible construct vector iterator range, this:

std::vector<std::string> vec(std::istream_iterator<std::string>{std::cin},                              std::istream_iterator<std::string>{}); 

but can compile , run code using c++11 uniform initialization syntax (note bracers), this:

std::vector<std::string> vec{std::istream_iterator<std::string>{std::cin},                              std::istream_iterator<std::string>{}}; 

what's going on here?

i know constructor taking initializer list gets priority on other forms of construction. shouldn't compiler resolve constructor taking initializer list containing 2 elements of std::istream_iterator? should error std::istream_iterator can't converted vectors value type std::string, right?

from §13.3.2/1 ([over.match.list])

when objects of non-aggregate class type t list-initialized (8.5.4), overload resolution selects constructor in 2 phases:

— initially, candidate functions initializer-list constructors (8.5.4) of class t , argument list consists of initializer list single argument.

— if no viable initializer-list constructor found, overload resolution performed again, candidate functions constructors of class t , argument list consists of elements of initializer list.

in case initializer list constructor deemed non-viable (because std::istream_iterator<std::string> not convertible std::string), , second condition applies. results in constructor taking 2 iterators selected.