No support for move-only types #3
Description
te doesn't seem to support move-only types, even though in the presence of move constructor and rvalue it will move the object and not use the copy constructor.
For example, given the following code that prints all calls to member functions of a tested class Circle:
#include "external/te/include/te.hpp"
#include <iostream>
using std::cout;
struct Drawable
{
void draw(std::ostream &out) const
{
te::call([](auto const &self, auto &out) { self.draw(out); }, *this, out);
}
};
struct Circle
{
Circle() { cout << "Circle()\n"; }
Circle(const Circle&) { cout << "Circle(const Circle&) ctor\n"; }
Circle& operator=(const Circle&) { cout << "operator=(const Circle&)\n"; }
Circle(Circle&&) { cout << "Circle(Circle&&)\n"; }
Circle& operator=(Circle&&) { cout << "operator=(Circle&&)\n"; }
~Circle() { cout << "~Circle()\n"; }
void draw(std::ostream &out) const { out << "Circle::draw\n"; }
};
void draw(const te::poly<Drawable>& drawable) { drawable.draw(cout); }
int main()
{
Circle circle{};
draw(std::move(circle));
}
we will get this output:
Circle()
Circle(Circle&&)
Circle::draw
~Circle()
~Circle()
But when we try to mark the copy constructor and copy assignment operator as deleted as below:
struct Circle
{
Circle() { cout << "Circle()\n"; }
Circle(const Circle&) = delete;
Circle& operator=(const Circle&) = delete;
Circle(Circle&&) { cout << "Circle(Circle&&)\n"; }
Circle& operator=(Circle&&) { cout << "operator=(Circle&&)\n"; }
~Circle() { cout << "~Circle()\n"; }
void draw(std::ostream &out) const { out << "Circle::draw\n"; }
};
we will get a compilation error:
main.cpp:33:19: error: invalid initialization of reference of type ‘const te::v1::poly<Drawable>&’ from expression of type ‘std::remove_reference<Circle&>::type {aka Circle}’
draw(std::move(circle));
~~~~~~~~~^~~~~~~~
main.cpp:28:6: note: in passing argument 1 of ‘void draw(const te::v1::poly<Drawable>&)’
void draw(const te::poly<Drawable>& drawable) { drawable.draw(cout); }
^~~~
Are there any plans to support noncopyable types?
Environment
OS: Ubuntu 17.10 x64
Compiler: GCC 7.2 x64