prog.cpp: In function 'int main()':
prog.cpp:15:4: error: use of deleted function 'foo& foo::operator=(const foo&)'
a = move(b);
^
prog.cpp:3:7: note: 'foo& foo::operator=(const foo&)' is implicitly deleted because the default definition would be ill-formed:
class foo
^
prog.cpp:3:7: error: use of deleted function 'std::unique_ptr<_Tp, _Dp>& std::unique_ptr<_Tp, _Dp>::operator=(const std::unique_ptr<_Tp, _Dp>&) [with _Tp = int; _Dp = std::default_delete<int>]'
In file included from /usr/include/c++/5/memory:81:0,
from prog.cpp:1:
/usr/include/c++/5/bits/unique_ptr.h:357:19: note: declared here
unique_ptr& operator=(const unique_ptr&) = delete;
^