diff --git a/main/Append.scala b/main/Append.scala
index 8278b544a..1e42b5ebf 100644
--- a/main/Append.scala
+++ b/main/Append.scala
@@ -38,4 +38,12 @@ object Append
 		def appendValues(a: Classpath, b: Seq[File]): Classpath = a ++ Attributed.blankSeq(b)
 		def appendValue(a: Classpath, b: File): Classpath = a :+ Attributed.blank(b)
 	}
+	implicit def appendSet[T, V <: T]: Sequence[Set[T], Set[V], V] = new Sequence[Set[T], Set[V], V] {
+		def appendValues(a: Set[T], b: Set[V]): Set[T] = a ++ b
+		def appendValue(a: Set[T], b: V): Set[T] = a + b
+	}
+	implicit def appendMap[A,B, X <: A, Y <: B]: Sequence[Map[A,B], Map[X,Y], (X,Y)] = new Sequence[Map[A,B], Map[X,Y], (X,Y)] {
+		def appendValues(a: Map[A,B], b: Map[X,Y]): Map[A,B] = a ++ b
+		def appendValue(a: Map[A,B], b: (X,Y)): Map[A,B] = a + b
+	}
 }
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