A single non-default case of a switch, paired with the scope captured
right after the case condition was processed (which already excludes the
values matched by earlier terminating cases).
Virtual node emitted once per switch statement. It pairs the switch subject
with each non-default case condition so rules can inspect the loose ==
comparison the switch performs, using the scope captured at each case
(which already excludes the values matched by earlier cases).
All local-variable write sites of a function-like body, with the set of
those whose written value was read on some path afterwards, and the set of
variable names the body mentions at all.