diff --git a/compile/inc/src/main/scala/sbt/inc/Compilations.scala b/compile/inc/src/main/scala/sbt/inc/Compilations.scala
index 86ab145d2..038984429 100644
--- a/compile/inc/src/main/scala/sbt/inc/Compilations.scala
+++ b/compile/inc/src/main/scala/sbt/inc/Compilations.scala
@@ -12,6 +12,7 @@ trait Compilations {
 object Compilations {
   val empty: Compilations = new MCompilations(Seq.empty)
   def make(s: Seq[Compilation]): Compilations = new MCompilations(s)
+	def merge(s: Traversable[Compilations]): Compilations = make((s flatMap { _.allCompilations }).toSeq.distinct)
 }
 
 private final class MCompilations(val allCompilations: Seq[Compilation]) extends Compilations {