Concepts

Concept is a term that describes a set of characteristics of a type. Concepts are a more convenient way to specify both what properties are expected from a type, and what properties a type has.

There was a proposal to include formal specification of concepts into the C++ language, so that the compiler could check the type requirements before template instantiation and in turn could produce much more sensible error messages in case a type did not fulfill the template requirements. This proposal was later dropped for various reasons. However, there are unofficial plans to add concepts to a future revision of the C++ language.

Basic concepts
DefaultConstructible	specifies that type has default constructor (concept)
CopyConstructible	specifies that type has copy constructor (concept)
MoveConstructible (C++11)	specifies that type has move constructor (concept)
CopyAssignable	specifies that type has copy assignment operator (concept)
MoveAssignable (C++11)	specifies that type can move assignment operator (concept)