Necessary for evaluating the coproduct of exportable instances (allowing any type
which implements the appropriate methods to count as, in some sense, defining an
import. Inspired by this implementation:
https://github.com/circe/circe/blob/backport/0.9.3/modules/shapes/src/main/scala/io/circe/shapes/CoproductInstances.scala
Necessary for evaluating the coproduct of exportable instances (allowing any type which implements the appropriate methods to count as, in some sense, defining an import. Inspired by this implementation: https://github.com/circe/circe/blob/backport/0.9.3/modules/shapes/src/main/scala/io/circe/shapes/CoproductInstances.scala