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puffnfresh/NoValueDiscarding.scala

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Define my own Unit which doesn't obey the crazy "value discarding" Scala rules.
Raw
NoValueDiscarding.scala
import language.implicitConversions
object Main {
object Unit
type Unit = Unit.type
implicit def unit2scalaunit(a: Unit): scala.Unit = ()
implicit def scalaunit2unit(a: scala.Unit): Unit = Unit
def printHelloWorld: Unit = {
println("Hello World")
// Won't compile
// 100
}
def main(args: Array[String]) {
printHelloWorld
printHelloWorld
}
}
@retronym
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retronym commented Jan 6, 2013 

% scala -Ywarn-value-discard 
Welcome to Scala version 2.9.1.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_27).
Type in expressions to have them evaluated.
Type :help for more information.

scala> def foo: Unit = 10
<console>:7: warning: discarded non-Unit value
       def foo: Unit = 10
                       ^
foo: Unit

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