C++ named requirements: LessThanComparable

The type must work with < operator and the result should have standard semantics.

# Notes

To satisfy this requirement, types that do not have built-in comparison operators have to provide a user-defined operator<.

For the types that are both EqualityComparable and LessThanComparable, the C++ standard library makes a distinction between

# Defect reports

DRApplied toBehavior as publishedCorrect behavior
LWG 2114(P2167R3)C++98convertibility to bool was too weak to reflect the expectation of implementationsrequirements strengthened

# See also