mx00s

You're right, there are several notable improvements in Idris2. I was mainly referring to the amount of code from the book that must be adapted. The QTT features, as you say, are opt-in; by default no new constraints are imposed.

There are some minor changes, but they are documented in detail [1]. The Idris2 repository maintains tests to detect any further divergence from the book [2].

I highly recommend the book. Typing in examples and getting experience collaborating with the compiler on edits is worthwhile. Even if you never use Idris(2) again after reading it, the demos on creating state machine DSLs with contextual invariants will leave a lasting impression.

[1] https://idris2.readthedocs.io/en/latest/typedd/typedd.html

[2] https://github.com/idris-lang/Idris2/tree/master/tests/typed...