add reusability checks; 3 test failures remaining
single stack is sufficient and desirable, because support checks done in support of another evaluation should see its hint set
add phase to Frame
correction, which introduces 1 more failure and 2 errors :/
warning
clean up 2 test errors by ensuring different position objects used per map entry
centralize and simplify result caching
cleanups
don't reuse position, enabling caching
inline variable