CODEWITHSUNDEEP
scalavalue-class
J Pullar
J Pullar

Reputation: 1935

Scala Prohibit allocation of value classes

According to the documentation on value classes, they may be allocated under a number of circumstances:

Allocation Summary

a value class is treated as another type.

a value class is assigned to an array.

doing runtime type tests, such as pattern matching.

Is there anyway to say,throw a compilation error if these circumstances occur?

Upvotes: 5

Views: 137

Answers (1)

Alexey Romanov
Alexey Romanov

Reputation: 170745

There is nothing built-in (AFAIK).

You could write an SBT plugin which inspects the .class files after compile task finishes (using a library like BCEL, ASM, etc.) and fails if it finds any value class constructor calls.

Alternately, you should be able to do the same with a compiler plugin (unfortunately, documentation I was able to find is quite old) with a little more difficulty.

Upvotes: 1

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