libawful 
A collection of awful archetypes for testing generic code
Overview
When writing a generic library, one often needs to test generic components with
types having infrequent characteristics. This is to make sure that a generic
component is not assuming more about its inputs than it should. libawful
is a collection of types with unusual properties that can be used to check for
corner cases when implementing generic components. The project contains a single
header, <awful.hpp>, which defines all the archetypes.
#include <awful.hpp>
#include <utility>
template <typename T, typename U>
struct naive_pair {
T first;
U second;
naive_pair() = default;
template <typename Other, typename = decltype(std::declval<Other>().first),
typename = decltype(std::declval<Other>().second)>
naive_pair(Other&& other)
: first(std::forward<Other>(other).first),
second(std::forward<Other>(other).second)
{ }
};
int main() {
naive_pair<awful::trapconstructible, int> pair;
auto copy = pair; // ERROR: naive_pair tries to copy-construct its first
// member from a non-const reference to `pair.first`.
}Compiler requirements
This is a C++14 library, and no effort whatsoever will be made to accommodate nonconforming compilers.