[trombonechamp]

Glad you like Paranoid Scientist, and thanks for the link to your project!

Yes, you're right that it only works on immutable data types. At first I had implemented something which copies the object, but this used way too much ram and ended up being quite buggy with a lot of edge cases.

I didn't invent the term hyperproperties (sadly). If you do end up implementing hyperproperties in runtime checks, you'll definitely want to look into to doing a statistical approach. The key to making this work is reservoir sampling (https://en.wikipedia.org/wiki/Reservoir_sampling) - there are some more details of how I did this in the Paranoid Scientist paper (https://arxiv.org/abs/1909.00427).