dillon1000/react

Repro for nonproblematic unreachable code

This case is specific to early return inside an inlined IIFE (which can often 
occur as a result of dropping manual memoization). When we inline IIFEs, as a 
reminder we wrap the body in a labeled block and convert returns to assignment 
of a temporary + break out of the label. 

Those reassignments themselves are getting a reactive scope assigned since the 
reassigned value has a mutable range. They don't really need a mutable range or 
scope, though. And then the presence of the `break` statements means that we can 
sometimes exit out of the scope before reaching the end - leading to unreachable 
code. 

This can only occur though where _all the values are already memoized_. So the 
code works just fine and even memoizes just fine - it's just that we have some 
extraneous scopes and there is technically unreachable code. I'll fix in a 
follow-up, adding a repro here.