[ fix ] invalid Cast instances
[ fix ] invalid Cast instances

integerToNat is only equal to `believe_me` at runtime, not at compile
time. You'd believe it cannot be a problem given that the implementation
of `Cast` is not exported but the REPL reduces everything.

mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm,mmhelloworld/idris-jvm