For the following class with only move constructor:

class Foo {
   public:
    Foo(const Foo& foo) = delete;
    Foo(Foo&& foo) = default;
    Foo() = default;
};

Why would initializing a vector with an initializing list like vector<Foo> vec{Foo()}; cause compilation error:

In file included from /usr/include/c++/11/vector:66,
                 from test_rand.cpp:3:
/usr/include/c++/11/bits/stl_uninitialized.h: In instantiation of ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = const Foo*; _ForwardIterator = Foo*]’:
/usr/include/c++/11/bits/stl_uninitialized.h:333:37:   required from ‘_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>&) [with _InputIterator = const Foo*; _ForwardIterator = Foo*; _Tp = Foo]’
/usr/include/c++/11/bits/stl_vector.h:1585:33:   required from ‘void std::vector<_Tp, _Alloc>::_M_range_initialize(_ForwardIterator, _ForwardIterator, std::forward_iterator_tag) [with _ForwardIterator = const Foo*; _Tp = Foo; _Alloc = std::allocator<Foo>]’
/usr/include/c++/11/bits/stl_vector.h:629:21:   required from ‘std::vector<_Tp, _Alloc>::vector(std::initializer_list<_Tp>, const allocator_type&) [with _Tp = Foo; _Alloc = std::allocator<Foo>; std::vector<_Tp, _Alloc>::allocator_type = std::allocator<Foo>]’
test_rand.cpp:13:23:   required from here
/usr/include/c++/11/bits/stl_uninitialized.h:138:72: error: static assertion failed: result type must be constructible from value type of input range
  138 |       static_assert(is_constructible<_ValueType2, decltype(*__first)>::value,
      |                                                                        ^~~~~
/usr/include/c++/11/bits/stl_uninitialized.h:138:72: note: ‘std::integral_constant<bool, false>::value’ evaluates to false

While there are no problems if I initialize an array in the same way as array<Foo, 1> arr{Foo()};.

I’d like to know:

1. What does this error message actually mean: I’ve searched the usage of is_constructible, and it seems like it is testing whether you can construct an object with certain parameters. Then what are the parameters that vector is trying to verify for type Foo?
2. Why are the behaviors for vector and array different?
3. What is the internal process when constructing vector like this: I thought that it would be the same as calling .push_back with an rvalue passed in, so that the move constructor could be called and it will induce no error.
4. Is it possible to make some modifications to the class Foo to make it work when constructing a vector with the initializing list? (without providing a copy constructor)