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Scala ADT encoding improvements

See original GitHub issue

For best practice with Scala ADTS:

All case class definitions should be marked as final to avoid subclassing
ADT trait should be marked extends Product with Serializable The reason for this is that the calculated LUB for the subtypes is not just the trait, due to the extra code mixed in by case class or case object. We want the inferred type to be just the trait, this especially helps when using code which has invariant type parameters.

Issue Analytics

State:
Created 7 years ago
Comments:5 (1 by maintainers)

Top GitHub Comments

1reaction

mbryzekcommented, May 22, 2020

case classes are final - closing issue

1reaction

fiadlielcommented, Apr 23, 2018

Making case classes final is best practice, for many reasons.

Some people discuss this issue at https://stackoverflow.com/questions/37184528/mock-case-class-in-scala-mockito

In general, these case classes model data. Data doesn’t need to be mocked, it just is (you can create a value at any time). You probably want to be looking at the interfaces that return data, and perhaps mocking them instead.

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