C++ named requirements: NullablePointer (since C++11)

Specifies that the type is a pointer-like object which can be compared to std::nullptr_t objects.

# Notes

Note that dereferencing (operator* or operator->) is not required for a NullablePointer type. A minimalistic type that satisfies these requirements is

# Defect reports

DRApplied toBehavior as publishedCorrect behavior
LWG 2114(P2167R3)C++11contextual convertibility to bool was too weak to reflect the expectation of implementationsrequirements strengthened