Cannot reserve, resize nor emplace_back in std::vector<te::poly<Type>>

[ArekPiekarz]

It's not possible to change internal or external size of std::vector that stores te::poly objects, nor emplace_back objects into it.

Example with reserving space in the vector:

#include "external/te/include/te.hpp"
#include <vector>

struct Drawable
{
    auto draw() -> REQUIRES(void, draw)
};

int main()
{
    std::vector<te::poly<Drawable>> drawables;
    drawables.reserve(1);
}

Its compilation fails with:

/usr/include/c++/7/type_traits:1162: error: invalid use of incomplete type ‘struct std::is_constructible<te::v1::poly<Drawable>, te::v1::poly<Drawable, te::v1::dynamic_storage, te::v1::static_vtable>&&>’
     struct __is_move_constructible_impl<_Tp, true>
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

When we change reserve to resize, we get the same error and additionally this one:

/usr/include/c++/7/bits/stl_construct.h:75: error: no matching function for call to ‘te::v1::poly<Drawable>::poly()’
     { ::new(static_cast<void*>(__p)) _T1(std::forward<_Args>(__args)...); }
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

When we change the code to test emplace_back with a potentially drawable object:

struct Circle
{
    void draw() {}
};

int main()
{
    std::vector<te::poly<Drawable>> drawables;
    drawables.emplace_back(Circle{});
}

we get the same error as in the reserve case.

Environment OS: Ubuntu 17.10 x64 Compiler: GCC 7.2 x64

[ArekPiekarz]

Thanks! resize(x) on vector still doesn't work, is it by design to not have an empty object? If so, it's worth noting it at least here.

The current compilation error is:

/usr/include/c++/7/bits/stl_construct.h:75: error: no matching function for call to ‘te::v1::poly<Drawable>::poly()’
     { ::new(static_cast<void*>(__p)) _T1(std::forward<_Args>(__args)...); }
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~