The C API currently allows creating immutable types from mutable bases. I can't find a case where this breaks things, but it's very hard to think about (and easy to skip thinking about) how this edge case affects things like cache invalidation.
I also don't immediately see a use case for this, so I think it's best to deprecate it, wait for 2 releases to see if anyone needs it, and remove it.
The C API currently allows creating immutable types from mutable bases. I can't find a case where this breaks things, but it's very hard to think about (and easy to skip thinking about) how this edge case affects things like cache invalidation.
I also don't immediately see a use case for this, so I think it's best to deprecate it, wait for 2 releases to see if anyone needs it, and remove it.