diff --git a/main-settings/src/test/scala/sbt/SlashSyntaxSpec.scala b/main-settings/src/test/scala/sbt/SlashSyntaxSpec.scala
index 929d48b93..8432a3f54 100644
--- a/main-settings/src/test/scala/sbt/SlashSyntaxSpec.scala
+++ b/main-settings/src/test/scala/sbt/SlashSyntaxSpec.scala
@@ -57,29 +57,20 @@ object BuildDSLInstances {
   implicit def arbAttrKey[A: Manifest]: Arbitrary[AttributeKey[_]] =
     Arbitrary(Gen.identifier map (AttributeKey[A](_)))
 
-  implicit def arbInputKey[A: Manifest]: Arbitrary[InputKey[A]] = Arbitrary {
-    val keyGen = Gen.identifier map (InputKey[A](_))
-    Gen.frequency(
+  def withScope[K <: Scoped.ScopingSetting[K]](keyGen: Gen[K]): Arbitrary[K] =
+    Arbitrary(Gen.frequency(
       50 -> keyGen,
       1 -> (for (key <- keyGen; scope <- arbitrary[Scope]) yield key in scope)
-    )
-  }
+    ))
 
-  implicit def arbSettingKey[A: Manifest]: Arbitrary[SettingKey[A]] = Arbitrary {
-    val keyGen = Gen.identifier map (SettingKey[A](_))
-    Gen.frequency(
-      50 -> keyGen,
-      1 -> (for (key <- keyGen; scope <- arbitrary[Scope]) yield key in scope)
-    )
-  }
+  implicit def arbInputKey[A: Manifest]: Arbitrary[InputKey[A]] =
+    withScope(Gen.identifier map (InputKey[A](_)))
 
-  implicit def arbTaskKey[A: Manifest]: Arbitrary[TaskKey[A]] = Arbitrary {
-    val keyGen = Gen.identifier map (TaskKey[A](_))
-    Gen.frequency(
-      50 -> keyGen,
-      1 -> (for (key <- keyGen; scope <- arbitrary[Scope]) yield key in scope)
-    )
-  }
+  implicit def arbSettingKey[A: Manifest]: Arbitrary[SettingKey[A]] =
+    withScope(Gen.identifier map (SettingKey[A](_)))
+
+  implicit def arbTaskKey[A: Manifest]: Arbitrary[TaskKey[A]] =
+    withScope(Gen.identifier map (TaskKey[A](_)))
 
   implicit def arbKey[A: Manifest]: Arbitrary[Key[_]] = Arbitrary {
     Gen.frequency[Key[_]](