Defined in header
move_constructible is satisfied if
T is a reference type, or if it is an object type where an object of that type can be constructed from an rvalue of that type in both direct- and copy-initialization contexts, with the usual semantics.
 Semantic requirements
T is an object type, then
move_constructible<T> is modeled only if given
rv, an rvalue of type
u2, a distinct object of type
the following are true:
- After the definition T u = rv;,
uis equal to
T(rv)is equal to
Tis not const-qualified, then
rv's resulting state (after the definition/expression is evaluated in either bullets above) is valid but unspecified; otherwise, it is unchanged.
 See also
| checks if a type can be constructed from an rvalue reference |