Clippy complained that it could be derived, but what we actually want is
for developers to be explicit about what rotations they are using, for
which `Rotation::cur()` is provided.
Due to this error being detected and returned early, in practice
`minimum_k` would always be `current_k + 1`, and the error would be
returned repeatedly (as more of the circuit could be processed) until
`k` was set large enough. We now simply suggest that the user try a
larger value of `k`.
In most places within `CircuitLayout`, we are flexible on `k`. However,
for tracking selectors we need to know the number of rows. We could
change this, but given that we also want the number of rows to be
accurate for rendering unusable rows, we can instead use this as an
opportunity to inform the user that they will need to bump `k`.
We `impl From<io::Error> for Error` to return `Error::TranscriptError`
because the transcript is the only source of `io::Error`.
`Error` no longer implements `PartialEq` because `io::Error` does not.
Tests can check for specific error cases with `assert!(matches!(..))`.
str4d
Carlos Pérez
Sean Bowe