diff --git a/src/org/rascalmpl/library/Prelude.java b/src/org/rascalmpl/library/Prelude.java
index 7de9444aeaa..e82d718052d 100644
--- a/src/org/rascalmpl/library/Prelude.java
+++ b/src/org/rascalmpl/library/Prelude.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2009-2013 CWI
+ * Copyright (c) 2009-2017 CWI
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -15,6 +15,8 @@
 
 package org.rascalmpl.library;
 
+import static org.rascalmpl.values.uptr.RascalValueFactory.TYPE_STORE_SUPPLIER;
+
 import java.io.BufferedReader;
 import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
@@ -79,6 +81,18 @@
 import org.rascalmpl.uri.LogicalMapResolver;
 import org.rascalmpl.uri.URIResolverRegistry;
 import org.rascalmpl.uri.URIUtil;
+import org.rascalmpl.values.uptr.ITree;
+import org.rascalmpl.values.uptr.ProductionAdapter;
+import org.rascalmpl.values.uptr.RascalValueFactory;
+import org.rascalmpl.values.uptr.SymbolAdapter;
+import org.rascalmpl.values.uptr.TreeAdapter;
+import org.rascalmpl.values.uptr.visitors.TreeVisitor;
+
+import com.ibm.icu.text.SimpleDateFormat;
+import com.ibm.icu.util.Calendar;
+import com.ibm.icu.util.TimeZone;
+import com.ibm.icu.util.ULocale;
+
 import io.usethesource.vallang.IBool;
 import io.usethesource.vallang.IConstructor;
 import io.usethesource.vallang.IDateTime;
@@ -105,23 +119,9 @@
 import io.usethesource.vallang.io.old.BinaryValueReader;
 import io.usethesource.vallang.io.old.BinaryValueWriter;
 import io.usethesource.vallang.random.RandomValueGenerator;
-import io.usethesource.vallang.random.util.TypeParameterBinder;
 import io.usethesource.vallang.type.Type;
 import io.usethesource.vallang.type.TypeFactory;
 import io.usethesource.vallang.type.TypeStore;
-import org.rascalmpl.values.uptr.ITree;
-import org.rascalmpl.values.uptr.ProductionAdapter;
-import org.rascalmpl.values.uptr.RascalValueFactory;
-import org.rascalmpl.values.uptr.SymbolAdapter;
-import org.rascalmpl.values.uptr.TreeAdapter;
-import org.rascalmpl.values.uptr.visitors.TreeVisitor;
-
-import com.ibm.icu.text.SimpleDateFormat;
-import com.ibm.icu.util.Calendar;
-import com.ibm.icu.util.TimeZone;
-import com.ibm.icu.util.ULocale;
-
-import static org.rascalmpl.values.uptr.RascalValueFactory.TYPE_STORE_SUPPLIER;
 
 @SuppressWarnings("deprecation")
 public class Prelude {
@@ -1054,7 +1054,7 @@ public ISet charsets() {
 		return w.done();
 	} 
 	
-	public IValue readFile(ISourceLocation sloc){
+	public IString readFile(ISourceLocation sloc){
 		if(trackIO) System.err.println("readFile: " + sloc);
 		try (Reader reader = URIResolverRegistry.getInstance().getCharacterReader(sloc);){
 			return consumeInputStream(reader);