diff --git a/src/org/rascalmpl/library/Type.java b/src/org/rascalmpl/library/Type.java
index 3cd470b715a..3ad86926a25 100644
--- a/src/org/rascalmpl/library/Type.java
+++ b/src/org/rascalmpl/library/Type.java
@@ -17,9 +17,12 @@
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.stream.Collectors;
 
 import org.rascalmpl.exceptions.RuntimeExceptionFactory;
 import org.rascalmpl.types.TypeReifier;
+import org.rascalmpl.values.IRascalValueFactory;
+import org.rascalmpl.values.RascalValueFactory;
 
 import io.usethesource.vallang.IBool;
 import io.usethesource.vallang.IConstructor;
@@ -36,10 +39,10 @@
 import io.usethesource.vallang.type.TypeStore;
 
 public class Type {
-	private final IValueFactory vf;
+	private final IRascalValueFactory vf;
 	private final IMap emptyMap;
 
-	public Type(IValueFactory vf) {
+	public Type(IRascalValueFactory vf) {
 		this.vf = vf;
 		emptyMap = vf.mapWriter().done();
 	}
@@ -122,38 +125,25 @@ public IValue make(IValue type, IString name, IList args, IMap keywordParameters
 	}
 
 	public IValue make(IConstructor cons, IList args, IMap keywordParameters) {
-		io.usethesource.vallang.type.Type constructor = new TypeReifier(vf).productionToConstructorType(cons);
-
-		assert constructor != null;
-		
-		IValue[] children = new IValue[args.length()];
-		io.usethesource.vallang.type.Type[] argsTypes = new io.usethesource.vallang.type.Type[args.length()];
-
-		for (int i = 0; i < args.length(); i++) {
-			children[i] = args.get(i);
-			argsTypes[i] = children[i].getType();
+		Map<String, IValue> kwMap = keywordParameters
+			.stream()
+			.map(v -> (ITuple) v)
+			.collect(Collectors.toMap(t -> ((IString) t.get(0)).getValue(), t -> t.get(1)));
+
+		if (cons.getConstructorType() == RascalValueFactory.Production_Default) {
+			// this is a parse tree production. We can just return the tree, and add the keyword parameters
+			return vf.appl(cons, args).asWithKeywordParameters().setParameters(kwMap);
 		}
-		
-		Map<String, IValue> kwmap;
-		
-		if(keywordParameters.size() == 0){
-			kwmap = Collections.emptyMap();
-		} else {
-			Iterator<Entry<IValue, IValue>> iter = keywordParameters.entryIterator();
-			kwmap = new HashMap<String, IValue>();
-			while(iter.hasNext()){
-				Entry<IValue, IValue> entry = iter.next();
-				kwmap.put(((IString) entry.getKey()).getValue(), entry.getValue());
-			}
+
+		if (cons.getConstructorType() != RascalValueFactory.Production_Cons) {
+			throw RuntimeExceptionFactory.illegalArgument(cons, "must be a cons or a prod rule.");
 		}
-		
-		try {
-			if (constructor == null) {
-				// TODO: improve error messaging, using specialized exception
-				throw RuntimeExceptionFactory.illegalArgument(cons, null, null);
-			}
-			return vf.constructor(constructor, children, kwmap);
 
+		io.usethesource.vallang.type.Type constructor = new TypeReifier(vf).productionToConstructorType(cons);
+	
+		try {
+			IValue[] children = args.stream().toArray(IValue[]::new);
+			return vf.constructor(constructor, children, kwMap);
 		}
 		catch (FactTypeUseException e) {
 			// TODO: improve error messaging, using specialized exception