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## Case 1: value class as parameter of method
$ copy-file changes/A0.scala src/main/scala/A.scala
$ copy-file changes/B0.scala src/main/scala/B.scala
$ copy-file changes/C0.scala src/main/scala/C.scala
# A is a normal class. B.foo accepts a parameter of type A. C calls B.foo, giving it `null`.
> compile
> run
# Make A a value class.
$ copy-file changes/A1.scala src/main/scala/A.scala
# The code no longer compiles because B.foo no longer accepts `null` as an argument.
# This means that we have invalidated C.scala, as expected!
-> compile
## Case 2: value class as return type of method with no parameter lists
$ copy-file changes/A0.scala src/main/scala/A.scala
$ copy-file changes/B1.scala src/main/scala/B.scala
$ copy-file changes/C1.scala src/main/scala/C.scala
# A is a normal class. B.bar takes no arguments and returns an instance of A. C calls B.bar.
> compile
> run
# Make A a value class.
$ copy-file changes/A1.scala src/main/scala/A.scala
# The code compiles. It will run iff C is recompiled because the signature of B.bar has changed,
# because A is now a value class.
> run
## Case 3: value class as return type of method with multiple parameter lists
$ copy-file changes/A0.scala src/main/scala/A.scala
$ copy-file changes/B2.scala src/main/scala/B.scala
$ copy-file changes/C2.scala src/main/scala/C.scala
# A is a normal class. B.bar takes two dummy arguments and returns an instance of A. C calls B.bar("")("").
> compile
> run
# Make A a value class.
$ copy-file changes/A1.scala src/main/scala/A.scala
# The code compiles. It will run iff C is recompiled because the signature of B.bar has changed,
# because A is now a value class.
> run
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