NFC: Use enum class for ActionClass.

[davidungar]

A small driver change inspired by batch mode: replacing an enum with an enum class to better enable future refactoring.

[davidungar]

@swift-ci please smoke test

[davidungar]

@swift-ci please smoke test

[shahmishal]

@swift-ci please smoke test

[jrose-apple]

:-/ I wish disabling implicit conversions wasn't tied to redundant scoping. Can we rename it to Kind or something so that "Action" isn't in the name twice?

[davidungar]

There's already an instance variable called Kind, otherwise Kind would be a great name. I could a) let the names collide, which might be confusing, b) rename the instance variable to MyKind, or c) rename ActionClass to ActionKind, which fails to eliminate the redundancy. Which would fit your stye the best?

[gottesmm]

@davidungar Have you considered making this a struct enum instead? The struct enum pattern allows for one to add methods to enums. Or is this used more as a pure enum?

[jrose-apple]

This is a Kind enum like the ones used for dyn_cast. I don't think the struct enum pattern is relevant here.

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For the name, I might suggest cheating by calling the field "RawKind", since it's being stored as an unsigned. It's definitely a downside of this naming style to have types and members conflict like this, though!

[davidungar]

@swift-ci please smoke test

[davidungar]

@gottesmm Thanks for the idea! Will keep it this way for now, since it's @jrose-apple 's code.
@jrose-apple Thanks for the concrete suggestions. Have taken them.

[gottesmm]

@davidungar I did not read the code, so I accepted Jordan's explanation. If you guys add a bunch of helper functions, it may make sense to perform that transition to change the helper functions to methods on a struct enum. But if you are only using it for dyn_cast, I feel that there is less strength in the case.