Upstreaming: More extensive assumptions of determinism

[cpovirk]

ad7d132

Unless I got confused, both that and -AassumePure/-AassumeSideEffectFree are necessary in order to get the results I'm hoping for.

When we look to upstream this, we should try the obvious alternative to my blunt approach: Instead of hardcoding if (true), make sure to propagate the value of allowNonDeterministic (which we always set to true and I don't think any framework code calls) to recursive fromNode and fromTree calls. Perhaps CF would even consider it a bug that they don't do this at present -- but I'm unsure, since I haven't thought through all the implications of undoing our purity/side-effect-free assumption.

[cpovirk]

The difference between -AassumePure and -AassumeSideEffectFree turns out not to matter in any of our samples or the internal projects we've been testing against (at least if I tested right :)). It's still possible that this is the case only because of other things we've done (like our persistent use of /*allowNonDeterministic=*/ true); I haven't tried to dig further.