diff --git a/src/org/rascalmpl/core/library/lang/rascalcore/compile/Compile.rsc b/src/org/rascalmpl/core/library/lang/rascalcore/compile/Compile.rsc
index 9cec7751..b5f53e99 100644
--- a/src/org/rascalmpl/core/library/lang/rascalcore/compile/Compile.rsc
+++ b/src/org/rascalmpl/core/library/lang/rascalcore/compile/Compile.rsc
@@ -6,6 +6,7 @@ import String;
 import util::Reflective;
 import util::Benchmark;
 import IO;
+import Set;
 import ValueIO;
 import util::Monitor;