Thank you for the comments. Based on these discussions, I went ahead and proposed a SIP. The main differences of the SIP compared to the proposal here are:
- Default names for context bound witnesses were dropped and deferred to a later SIP. There’s no consensus yet on what is the best technique for supporting such names in the presence of multiple context bounds.
- The improvements to the deferred givens were incorporated.
- There is some discussion regarding the alternative of dropping context bounds and restricting the language to just using clauses.