dillon1000/react

Transitive mixed type, take 2

This is a redo of #1640 now that we've established the necessary infrastructure, 
most notably `Effect.ConditionallyMutate` and `noAlias` from #2103 earlier in 
this stack. We can now understand the semantics of hooks that return deeply 
readonly values composed of primitives, arrays, or objects such that any 
`.map()` or `.filter()` calls are guaranteed to be the corresponding array 
methods. That further allows us to refine, since we know that the lambdas passed 
to these calls can't alias, are conditionally mutable, etc. All in all this 
should let us memoize less in practice.